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  • Artikel  (87)
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  • biodiversity
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  • Springer  (87)
  • American Association of Petroleum Geologists
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  • 1995-1999  (87)
  • 1945-1949
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  • 1945
  • Biologie  (77)
  • Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft  (8)
  • Architektur, Bauingenieurwesen, Vermessung  (2)
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  • Artikel  (87)
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  • Springer  (87)
  • American Association of Petroleum Geologists
  • American Geophysical Union
  • American Physical Society
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  • 1995-1999  (87)
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  • 1
    Digitale Medien
    Digitale Medien
    Discrete stability of the Differential System Method evaluated with geostatistical techniques (1998)
    Springer
    Stochastic environmental research and risk assessment 12 (1998), S. 191-204 
    Details
    ISSN: 1436-3259
    Schlagwort(e): Keywords: groundwater flow ; inverse problems ; stability ; geostatistical interpolation ; kriging.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Energietechnik , Geographie , Geologie und Paläontologie
    Notizen: Abstract The Differential System Method (DSM) permits identification of the physical parameters of finite-difference groundwater flow models in a confined aquifer when piezometric head and source terms are known at each point of the finite-difference lattice for at least two independent flow situations for which the hydraulic gradients are not parallel. Since piezometric head data are usually few and sparse, interpolation of the measured data onto a regular grid can be performed with geostatistical techniques. We apply kriging to the sparse data of a synthetic aquifer to evaluate the stability of the DSM with respect to uncorrelated measurement errors and interpolation errors. The numerical results show that the DSM is stable.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004770050017
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  • 2
    Digitale Medien
    Digitale Medien
    Comparative efficacy of Beauveria bassiana, Bacillus thuringiensis, and aldicarb for control of Colorado potato beetle in an irrigated desert agroecosystem and their effects on biodiversity (1999)
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 189-200 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Beauveria bassiana ; Colorado potato beetle ; Leptinotarsa decemlineata ; Bacillus thuringiensis ; biodiversity ; desert cropping system ; microbial control ; nontarget organisms
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Five weekly applications of Beauveria bassiana (Balsamo) Vuillemin, a genetically engineered isolate of Bacillus thuringiensis Berliner (Raven®), and aldicarb (Temik®) were compared for control of Colorado potato beetle, Leptinotarsa decemlineata (Say) in an irrigated desert cropping system. B. thuringiensis was applied using low and high label rates (1.17 and 7.0 l ha−1). B. bassiana was applied at 5×1013 spores ha−1. Aldicarb (Rh^one-Poulenc), applied at 3.37 kg a.i. ha−1 provided the greatest beetle control and potato yields (45 metric tons ha−1), but overall lowest biodiversity in nontarget organisms, particularly predatory Heteroptera. Low and high rates of B. thuringiensis produced fair to excellent beetle control, yielded 33 and 40 metric tons ha−1 and enabled good survival in predatory Heteroptera and other nontargets. Plots treated with B. bassiana resulted in poor control of beetles prior to row closure after which fair to good control was achieved. Yield in the Beauveria-treated plots was 33 metric tons ha−1 and effect on biodiversity was comparable to the Bt-treated plots. The lowest number of overwintering adult L. decemlineata was found in the plots treated with bacteria and fungi (0.68–0.84 adults/0.03 m−3 of soil) and the highest was found in control and aldicarb plots (3.44 and 1.84 adults/0.03 m3 of soil). Aphids and leafhoppers showed higher densities in plots treated with microbial control agents, but were eliminated from plots treated with aldicarb.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003831112208
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  • 3
    Digitale Medien
    Digitale Medien
    A Two-Patch Model of Gambian Sleeping Sickness: Application to Vector Control Strategies in a Village and Plantations (1998)
    Springer
    Acta biotheoretica 46 (1998), S. 207-222 
    Details
    ISSN: 1572-8358
    Schlagwort(e): Epidemiology ; sleeping sickness ; vector controls ; differential equations ; spacialization ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A compartmental model is described for the spread of Gambian sleeping sickness in a spatially heterogeneous environment in which vector and human populations migrate between two "patches": the village and the plantations. The number of equilibrium points depends on two "summary parameters": gr the proportion removed among human infectives, and R0, the basic reproduction number. The origin is stable for R0 〈1 and unstable for R0 〉1. Control strategies are assessed by studying the mix of vector control between the two patches that bring R0 below 1. The results demonstrate the importance of vector control in the plantations. For example if 20 percent of flies are in the village and the blood meal rate in the village is 10 percent, then a 20 percent added vector mortality in the village must be combined with a 9 percent added mortality in the plantations in order to bring R0 below 1. The results are quite insentive to the blood meal rate in the village. Optimal strategies (that minimize the total number of flies trapped in both patches) are briefly discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1001776926167
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  • 4
    Digitale Medien
    Digitale Medien
    Can the ecosystem mimic hypotheses be applied to farms in African savannahs? (1999)
    Springer
    Agroforestry systems 45 (1999), S. 131-158 
    Details
    ISSN: 1572-9680
    Schlagwort(e): competition ; fertility ; microclimate ; risk ; stability ; water
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The first ecosystem mimic hypothesis suggests clear advantages if man-made land use systems do not deviate greatly in their resource use patterns from natural ecosystems typical of a given climatic zone. The second hypothesis claims that additional advantages will accrue if agroecosystems also maintain a substantial part of the diversity of natural systems. We test these hypotheses for the savannah zone of sub-Saharan Africa, with its low soil fertility and variable rainfall. Where annual food crops replace the natural grass understorey of savannah systems, water use will decrease and stream and groundwater flow change, unless tree density increases relative to the natural situation. Increasing tree density, however, will decrease crop yields, unless the trees meet specific criteria. Food crop production in the parkland systems may benefit from lower temperatures under tree canopies, but water use by trees providing this shade will prevent crops from benefiting. In old parkland trees that farmers have traditionally retained when opening fields for crops, water use per unit shade is less than in most fast growing trees introduced for agroforestry trials. Strong competition between plants adapted to years with different rainfall patterns may stabilise total system productivity -- but this will be appreciated by a farmer only if the components are of comparable value. The best precondition for farmers to maintain diversity in their agroecosystem hinges on the availability of a broad basket of choices, without clear winners or 'best bets'.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006245605705
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  • 5
    Digitale Medien
    Digitale Medien
    Indigenous fruit trees of Madagascar: potential components of agroforestry systems to improve human nutrition and restore biological diversity (1999)
    Springer
    Agroforestry systems 46 (1999), S. 289-310 
    Details
    ISSN: 1572-9680
    Schlagwort(e): biodiversity ; domestication ; ethnobotany ; gender ; indigenous knowledge ; non-timber forest product
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Biodiversity in Eastern Madagascar is threatened by slash and burn agriculture, which is resulting in species extinction, land and soil degradation and rural impoverishment. An ethnobotanical study was undertaken to determine the domestication potential of indigenous fruit tree species as components of agroforestry systems. Four major selection criteria were used: nutritional and income needs of the population, diversification of the agroecosystem, and protection of plant and animal diversity. At three sites, Andasibe, Masoala and Ranomafana, in the humid primary forest region of Eastern Madagascar, a total of 150 wild fruit species from 82 genera and 42 families, of which 85% were indigenous and 92% of woody habit, were identified. In contrast to most of the deforested areas in Madagascar, the rural population in these areas possess an intimate knowledge of indigenous plant resources. Most of the indigenous fruits are collected from the forest but for a few species, domestication is initiated by managing naturally established species or by planting individual trees in agricultural fields. Wild fruits supplement the daily diet, substitute for exotic fruits, gain importance during periods of food shortage and are most appreciated by children. Commercialization of wild fruits is mainly undertaken by the poorer section of the population. Gender related differences in knowledge and preferences on species were identified and related to the respective household responsibilities. A list of the 26 priority species was established based on the preferences of children, women and men at the three sites. Local, fruit-eating lemur species are also highly dependent on indigenous fruit trees and are crucial for successful regeneration of forest vegetation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006295530509
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  • 6
    Digitale Medien
    Digitale Medien
    Determination of an Optimal Pitfall Trap Size for Sampling Spiders in a Western Australian Jarrah Forest (1999)
    Springer
    Journal of insect conservation 3 (1999), S. 297-307 
    Details
    ISSN: 1572-9753
    Schlagwort(e): spider ; pitfall traps ; sampling methods ; biodiversity ; invertebrates
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Wissenschaftskunde und Wissenschaftsorganisation, Hochschul- und Universitätswesen, Museumswissenschaft
    Notizen: Abstract Pitfall trapping is a sampling technique extensively used to sample surface foraging invertebrates for biological diversity studies and ecological monitoring. To date, very few invertebrate studies have considered what trap size is optimal for sampling spiders. This study presents preliminary findings from a single short sampling period on the role of trap size in sampling spiders in a Western Australian Jarrah forest. Four different trap diameters (4.3, 7.0, 11.1 and 17.4 cm) were examined (4 trap sizes × 15 replicates = 60 traps). Two-way ANOVAs revealed no significant interaction effects between trap size or the spatial positioning of transects within the study site along which the pitfall traps were arranged. Post-hoc tests revealed abundance, family richness and species richness increased with increasing trap sizes for traps ≥7.0 cm. No significant differences in these dependent variables occurred between 4.3 and 7.0 cm traps, or for species richness between 11.1 and 17.4 cm traps. Determination of an optimal trap size was undertaken by bootstrapping and calculating species accumulation curves for increasing numbers of traps used. Three different criteria were considered: equivalent number of traps (15), standardized sampling intensity (cumulative trap circumference, approximately 207 cm) and standardized cumulative handling time (approximately 1 hour 17 minutes). The largest trap size (17.4 cm) was most efficient in terms of number of traps and trap circumference. For the same number of traps, it caught 19 species whereas all other trap sizes caught ≤ten species. At the standardized circumference, it caught seven species whereas all other trap sizes caught five. For handling time, however, the two largest trap sizes (17.4 and 11.1 cm) were optimal. Both caught nine species whereas all other traps caught 〈eight. These results suggest the largest trap size was optimal. Given that the 11.1 cm trap performed similarly with respect to handling time, however, we tentatively considered this size most appropriate owing to an ethical consideration – smaller trap sizes may decrease the potential for capture of non-target species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009682527012
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  • 7
    Digitale Medien
    Digitale Medien
    A comparison of vacuum sampling versus sweep-netting for arthropod biodiversity measurements in California coastal sage scrub (1998)
    Springer
    Journal of insect conservation 2 (1998), S. 99-106 
    Details
    ISSN: 1572-9753
    Schlagwort(e): vacuum sampler ; sweep-net ; shrubs ; biodiversity ; arthropods.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Wissenschaftskunde und Wissenschaftsorganisation, Hochschul- und Universitätswesen, Museumswissenschaft
    Notizen: Abstract The recent growth of conservation biology has demanded that faster and more effective measures of biodiversity be utilized. Arthropods, due to high levels of diversity and their relative ease of capture, are often the subject of such surveys. The vacuum sampler, used quite often in the context of agricultural arthropod surveys, has never been adequately evaluated or compared to more traditional collection techniques in relatively complex ecosystems. The purpose of this study was to determine whether the vacuum sampler was more or less effective than a sweep-net in measuring arthropod biodiversity in California coastal sage scrub. The results show that significantly more individuals were collected by the vacuum sampler per unit effort for three out of six orders of arthropods examined. In addition, the vacuum sampler collected a significantly greater number of arthropod species than the sweep-net technique for two out of the six orders sampled. There were no significant differences in the number of species collected for the remaining four orders. We feel these findings are important for arthropod biodiversity studies utilized for conservation efforts as the vacuum sampler can attain a level of efficiency and sensitivity (with regard to species detection) that sweep-net techniques cannot. © Rapid Science Ltd. 1998
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009653021706
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  • 8
    Digitale Medien
    Digitale Medien
    Acoustic monitoring of Orthoptera and its potential for conservation (1998)
    Springer
    Journal of insect conservation 2 (1998), S. 217-223 
    Details
    ISSN: 1572-9753
    Schlagwort(e): conservation monitoring ; bioacoustics ; biodiversity ; Orthoptera ; tropical forests.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Wissenschaftskunde und Wissenschaftsorganisation, Hochschul- und Universitätswesen, Museumswissenschaft
    Notizen: Abstract Songs of Orthoptera can be used for inventorying and monitoring of individual species and communities. Acoustic parameters such as carrier frequency and pulse rates allow the definition of recognizable taxonomic units (RTUs) which help to overcome the taxonomic impediment due to our scanty knowledge, particularly of tropical faunas. Bioacoustic diversity is a first estimate for species richness and provides baseline data which can be a prerequisite for conservation. Additional ecological and behavioural information such as habitat preference and singing schedules can be inferred. Many Orthoptera are sensitive indicator species for habitat quality in temperate and tropical ecosystems. Examples are given for evaluation of habitat quality and deterioration by acoustic detection of Orthoptera.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009695813606
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  • 9
    Digitale Medien
    Digitale Medien
    The taxonomic impediment in orthopteran research and conservation (1998)
    Springer
    Journal of insect conservation 2 (1998), S. 151-159 
    Details
    ISSN: 1572-9753
    Schlagwort(e): Orthoptera ; biodiversity ; taxonomy ; conservation.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Wissenschaftskunde und Wissenschaftsorganisation, Hochschul- und Universitätswesen, Museumswissenschaft
    Notizen: Abstract It is estimated that only 10–15% of the world's insect fauna has been described and named. Efforts to inventory insect biodiversity are hampered by this taxonomic impediment, which is compounded by the logistical problems of an insufficient taxonomic workforce and their remote location in museums thousands of miles from the areas of highest biodiversity. Compared to most other invertebrate groups however, the taxonomic impediment is relatively benign in the order Orthoptera. This is a small to medium-sized order (approximately 20 000 described species) which is well known taxonomically, owing to the group's agricultural importance worldwide. Furthermore, orthopteran taxonomists are now fortunate to have a published up-to-date catalogue of all known species, which has just become accessible as a regularly updated database on the World Wide Web. Whilst new information technology, in the form of e-mail networks, World Wide Web sites and CD-ROM information archives, is already enhancing communication between specialists and helping to reduce the logistical problems of documenting orthopteran biodiversity, a major reinvestment in basic taxonomic research is needed if we are to reduce the existing taxonomic impediment significantly. There is general agreement that an internationally coordinated approach will be necessary and priorities must be set to tackle the biodiversity/systematics crisis. In the future, the Orthoptera can make an important contribution to invertebrate faunal surveys and have potential as an indicator taxon. Furthermore, the Orthoptera Species File establishes a taxonomic framework which could be readily enlarged to include geographic data and phenology of species from existing museum specimens.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009633811789
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  • 10
    Digitale Medien
    Digitale Medien
    Emergence of symmetric, modular, and reciprocal connections in recurrent networks with Hebbian learning (1999)
    Springer
    Biological cybernetics 81 (1999), S. 211-225 
    Details
    ISSN: 1432-0770
    Schlagwort(e): Key words: Hebbian learning rule ; attractor dynamics ; symmetric connections ; multiplicative normalization ; self-organization ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Informatik , Physik
    Notizen: Abstract. While learning and development are well characterized in feedforward networks, these features are more difficult to analyze in recurrent networks due to the increased complexity of dual dynamics – the rapid dynamics arising from activation states and the slow dynamics arising from learning or developmental plasticity. We present analytical and numerical results that consider dual dynamics in a recurrent network undergoing Hebbian learning with either constant weight decay or weight normalization. Starting from initially random connections, the recurrent network develops symmetric or near-symmetric connections through Hebbian learning. Reciprocity and modularity arise naturally through correlations in the activation states. Additionally, weight normalization may be better than constant weight decay for the development of multiple attractor states that allow a diverse representation of the inputs. These results suggest a natural mechanism by which synaptic plasticity in recurrent networks such as cortical and brainstem premotor circuits could enhance neural computation and the generation of motor programs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004220050557
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  • 11
    Digitale Medien
    Digitale Medien
    Bicelle-based liquid crystals for NMR-measurement of dipolar couplings at acidic and basic pH values (1999)
    Springer
    Journal of biomolecular NMR 13 (1999), S. 187-191 
    Details
    ISSN: 1573-5001
    Schlagwort(e): alignment ; bicelle ; dipolar coupling ; liquid crystal ; pH ; stability ; ubiquitin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract It is demonstrated that mixtures of ditetradecyl- phosphatidylcholine or didodecyl-phoshatidylcholine and dihexyl- phosphatidylcholine in water form lyotropic liquid crystalline phases under similar conditions as previously reported for bicelles consisting of dimyristoyl-phosphatidylcholine (DMPC) and dihexanoyl- phosphatidylcholine (DHPC). The carboxy-ester bonds present in DMPC and DHPC are replaced by ether linkages in their alkyl analogs, which prevents acid- or base-catalyzed hydrolysis of these compounds. 15N-1H dipolar couplings measured for ubiquitin over the 2.3–10.4pH range indicate that this protein retains a backbone conformation which is very similar to its structure at pH 6.5 over this entire range.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008395916985
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  • 12
    Digitale Medien
    Digitale Medien
    The role of the amateur in mycology—what would we do without them! (1998)
    Springer
    Mycoscience 39 (1998), S. 513-522 
    Details
    ISSN: 1618-2545
    Schlagwort(e): biodiversity ; fungal taxonomy ; history of biology ; natural history ; organismal inventory
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The amateur's role in the history of mycology will be traced from its early roots deeply based in the collection of fungi for food to the amateur's present day activities. Attention will be drawn to the most important key amateur figures studying fungi solely or as a wider part of natural history in the eighteenth and nineteenth centuries, and the early part of the present century. How their work influenced the development of mycology will be demonstrated. It is often forgotten that the authorities attached to fungal names, including those we use in mycology on a daily basis, often belong to amateurs. The true professions of these amateurs, the net-work of correspondents they developed, etc. will be revealed and discussed in the context of an overall understanding of fungi as organisms. In addition the formation of mycological societies, and how they have become a focus of amateur activity and a source of accurate and disciplined information valuable to professional scientists will be plotted. The kind of work undertaken by amateurs I refer to will be demonstrated by documenting the activities of the British Mycological Society which celebrated its centenary in 1996. The continuing work of this band of workers and their counterparts throughout the world in the closing years of the millennium will be described. It is argued that they are nationally important and necessary resources, despite many governments or their advisers, especially the most influential ones, being under the delusion that systematics is not cutting edge science. It is also emphasized that amateurs will have an even more important role to play in the future as custodians of knowledge—until hopefully opinions change.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02460913
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  • 13
    Digitale Medien
    Digitale Medien
    The role of competition in invertebrate community development in a recently formed stream in Glacier Bay National Park, Alaska (1999)
    Springer
    Aquatic ecology 33 (1999), S. 175-184 
    Details
    ISSN: 1573-5125
    Schlagwort(e): Chironomidae ; interspecific competition ; streams ; stability ; succession
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract New streams formed following ice recession in Glacier Bay National Park, southeastern Alaska allow insights into the role of abiotic and biotic interactions in the assemblage of benthic communities. Reductions in abundance of a pioneer chironomid colonizer, Diamesa alpina/lupus, in one new stream, Wolf Point Creek, is considered to be a result of competitive interactions with subsequent colonizers, as opposed to intolerance of warmer water temperature as previously suggested. Reduced densities of potential competitors (25–50 larvae per 500 cm2) in a cobble transplant experiment between streams, allowed persistence of D. alpina/lupus at low densities. In addition, significantly more D. alpina/lupus larvae emigrated from artificial stream channels containing other chironomid taxa than channels without potential competitors while there was no significant correlation of emigration with water temperature. A small number of D. alpina/lupus transplanted from a cold stream (4–6 °C) survived at water temperatures of 10–15 °C for 1 week. These results infer that interference competition is the causal mechanism in the decline of D. alpina/lupus. Complete exclusion of D. alpina/lupus from the stream has not occurred and water temperature may play a role in partitioning D. alpina/lupus from other taxa on a temporal or a spatial basis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009961000854
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  • 14
    Digitale Medien
    Digitale Medien
    Species density of phanerogams and bryophytes in Dutch forests (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 147-157 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; species density ; phanerogams ; bryophytes ; forests
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In Dutch forests the species density of vascular plants ranges from 1 to 61 species per 300 m2. The vascular plant species density is high in the coastal dunes, southern Limburg, river valleys, and fen areas. With the exception of southern Limburg, these areas constitute the Holocene part of the Netherlands. Low species densities occur in the sandy centre of the country. To a large extent, the areas of high species density of vascular plants follow the main river valleys. The bryophyte species densities range from 0 to 21 species per 300 m2. High bryophyte species densities occur mainly in the sandy centre and in the north-eastern part of the Netherlands. The highest species densities occur in fen woodlands and derelict coppices. Bryophyte species density is low in the coastal dunes and the very young woodlands in the recently reclaimed areas (polders). The species density contour maps of vascular plants and bryophytes in the Netherlands have little in common.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008824100823
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  • 15
    Digitale Medien
    Digitale Medien
    Biodiversity of Dutch forest ecosystems as affected by receding groundwater levels and atmospheric deposition (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 221-228 
    Details
    ISSN: 1572-9710
    Schlagwort(e): Forest ; biodiversity ; desiccation ; nitrogen deposition ; acidification ; Netherlands
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Forests in the Netherlands are heavily under stress. Recent surveys suggest that about one-third of the forest area in the Netherlands is affected by desiccation. Generally, plant species of moist situations decline, whereas drought tolerant species tend to increase. Besides desiccation, adverse ecological effects of acidification and nitrogen deposition also occur. Their combined action is held responsible for, among others, the decline of oligotrophic vascular plants, lichens and mycorrhizal fungi. At the same time, N-demanding species increase, which is partly caused by nitrogen deposition, and is partly a secondary effect of desiccation through aeration and concomitant mineralization. Nutrient balance of trees is disrupted. Effects on animals also occur: small snails in forest on acid soil decrease, causing Ca deficiency in birds. Measures to reduce these impacts include restoration of the former hydrology, liming, fertilization and removal of N-saturated littler layers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008888519478
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  • 16
    Digitale Medien
    Digitale Medien
    In search of the best correlates for local organismal biodiversity in cultivated areas (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 297-309 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; species diversity ; correlation ; indicator taxa
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Based on a transect consisting of 19 identical trap stations in cultivated areas and seminatural habitats, the correlation of species numbers of higher taxonomic groups with total species numbers of flowering plants and arthropods per trap site was calculated. A total of 191214 invertebrate specimens and 2221 species of plants and animals were analysed. Considering the value of the correlation coefficient R2 as well as the effort for sorting and identification, a ‘top twenty’ list of indicator groups favours Heteroptera, flowering plants, Symphyta and aculeate Hymenoptera as the best choice for biodiversity evaluation. In general, flight traps rated better than pitfall traps. In most taxonomic groups, diversity indices such as the Shannon and the Simpson index were only weakly correlated with local species diversity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008873510817
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  • 17
    Digitale Medien
    Digitale Medien
    Biodiversity and functioning of polychaetes in benthic sediments (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 1133-1145 
    Details
    ISSN: 1572-9710
    Schlagwort(e): polychaetes ; biodiversity ; marine sediments ; role of polychaetes ; recruitment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Polychaetes are well represented in most marine and estuarine environments, both in terms of number of individuals and species, and they typically contribute a significant percentage of the total macrofaunal diversity. They exhibit considerable variations in recruitment in both time and space, which is then often reflected in adult distributions. Whilst families and genera of polychaetes have wide distributions, normally species have discrete distributions. Polychaetes are often classified according to their diverse feeding guilds. They play a major role in the functioning of benthic communities, in terms of recycling and reworking of benthic sediments, bioturbating sediments and in the burial of organic matter. Some species form dense tubiculous colonies which can radically change recruitment patterns of other infaunal organisms. Polychaetes, by their burrowing and feeding activity, may considerably enhance various sedimentary processes. However, much remains to be learnt as to how benthic communities function, and how they may change in function as they are increasingly being impacted especially in coastal waters adjacent to centres of population.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008871430178
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  • 18
    Digitale Medien
    Digitale Medien
    Biodiversity of Collembola and their functional role in the ecosystem (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 1207-1219 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; biogeography ; life forms ; guilds ; functional role in ecosystems ; Collembola
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract More than 6500 species of Collembola are known from throughout the world and these are only a small part of the still undescribed species. There are many checklists and catalogues of Collembola for smaller territories and entire continents. Biogeographical analyses have been made for some genera and smaller territories. The most serious problems for a global biogeographical analysis is the lack of enough records from immense territories of all continents. Local biodiversity of Collembola can be very high, reaching over 100 species in small mountain ranges. Sampling methods do not impede documenting biodiversity on a global scale. Collembola have well differentiated ecomorphological life-forms and feeding guilds which enable the functional role that Collembola play in ecosystems to be recognised in some degree. Collembola play an important role in plant litter decomposition processes and in forming soil microstructure. They are hosts of many parasitic Protozoa, Nematoda, Trematoda and pathogenic bacteria and in turn are attacked by different predators. They utilise as food Protozoa, Nematoda, Rotatoria, Enchytraeidae, invertebrate carrion, bacteria, fungi, algae, plant litter, live plant tissues, and some plant pathogens. Soil acidification, nitrogen supply, global climate change and intensive farming have greatly impacted collembolan diversity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008887817883
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  • 19
    Digitale Medien
    Digitale Medien
    Freshwater protozoa: biodiversity and ecological function (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 1163-1186 
    Details
    ISSN: 1572-9710
    Schlagwort(e): Protozoa ; freshwater ; biodiversity ; species-number ; ecological function
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The purpose of this article is to pull together various elements from current knowledge regarding the natural history of free-living protozoa in fresh waters. We define their functional role, set the likely limits of ‘biodiversity’, and explore how the two may be related. Protozoa are unicellular, phagotrophic organisms, and 16 phyla of protists contain free-living freshwater protozoan species. They are the most important grazers of microbes in aquatic environments and the only grazers of any importance in anoxic habitats. In sediments, ciliates are usually the dominant protozoans. Benthic ciliate biomass accounts for slightly less than 10% of total benthic invertebrate biomass, but ciliate production may equal or even exceed invertebrate production. Freshwater protozoan species are probably ubiquitous, although many may persist locally for long periods in a cryptic state – as ‘potential’ rather than ‘active’ biodiversity. As protozoa are among the largest and most complex of micro-organisms, it follows that bacteria and all other smaller, more numerous microbes are also ubiquitous. The number of protozoan species recorded in local surveys (232) is about 10% of the estimated global species richness (2390). The 'seedbank’ of protozoan (and microbial) species ensures that local microbial diversity is never so impoverished that it cannot play its full part in ecosystem functions such as carbon fixation and nutrient cycling.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008879616066
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  • 20
    Digitale Medien
    Digitale Medien
    Ant biodiversity and its relationship to ecosystem functioning: a review (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 1221-1244 
    Details
    ISSN: 1572-9710
    Schlagwort(e): ants ; biodiversity ; ecosystem engineers ; mounds ; soil function
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Ants are important components of ecosystems not only because they constitute a great part of the animal biomass but also because they act as ecosystem engineers. Ant biodiversity is incredibly high and these organisms are highly responsive to human impact, which obviously reduces its richness. However, it is not clear how such disturbance damages the maintenance of ant services to the ecosystem. Ants are important in below ground processes through the alteration of the physical and chemical environment and through their effects on plants, microorganisms, and other soil organisms. This review summarizes the information available on ant biodiversity patterns, how it can be quantified, and how biodiversity is affected by human impacts such as land use change, pollution, invasions, and climate change. The role of ants in ecosystems is discussed, mainly from the perspective of the effects of ground-dwelling ants on soil processes and function, emphasizing their role as ecosystem engineers. Some lines of research are suggested after demonstrating the gaps in our current information on ant-soil interactions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008891901953
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  • 21
    Digitale Medien
    Digitale Medien
    From single-species to biodiversity – making the transition in fisheries management (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 45-54 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; fishery management ; fishery status ; incentives ; institutions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Biodiversity protection is a key issue for fishery management, but there are large uncertainties about its implementation. Incentives for biodiversity protection are created and shaped by the institutional environment which establishes the rights, rules and responsibilities of human behavior. Making the institutional transition from an orientation of single-species to one of biodiversity is complicated by the history of fisheries management, the current state of fisheries and the structures and procedures of fishery decision making. Significant challenges to institutional design for biodiversity lie in the agencies, decision bodies, regulations, and enforcement within which management is implemented. Failure to address the institutional issues surrounding biodiversity will lead to poor implementation and continued ecological simplification. Without serious and fresh attention to innovative design, the institutional environment of fisheries is likely to be completely inadequate to the task of protecting biodiversity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008852906430
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  • 22
    Digitale Medien
    Digitale Medien
    Competing Models of Stability in Complex, Evolving Systems: Kauffman vs. Simon (1998)
    Springer
    Biology and philosophy 13 (1998), S. 541-554 
    Details
    ISSN: 1572-8404
    Schlagwort(e): complex natural system ; stability ; evolvability ; decomposable hierarchy ; genetic network ; Random NK Boolean Network
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Philosophie
    Notizen: Abstract I criticize Herbert Simon's argument for the claim that complex natural systems must constitute decomposable, mereological or functional hierarchies. The argument depends on certain assumptions about the requirements for the successful evolution of complex systems, most importantly, the existence of stable, intermediate stages in evolution. Simon offers an abstract model of any process that succeeds in meeting these requirements. This model necessarily involves construction through a decomposable hierarchy, and thus suggests that any complex, natural, i.e., evolved, system is constituted by a decomposable hierarchy. I argue that Stuart Kauffman's recent models of genetic regulatory networks succeed in specifying processes that could meet Simon's requirements for evolvability without requiring construction through a decomposable hierarchy. Since Kauffman's models are at least as plausible as Simon's model, Simon's argument that complex natural systems must constitute decomposable, mereological or functional hierarchies does not succeed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006567306546
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  • 23
    Digitale Medien
    Digitale Medien
    Norway Maple (Acer platanoides) Invasion of a Natural Forest Stand: Understory Consequence and Regeneration Pattern (1999)
    Springer
    Biological invasions 1 (1999), S. 215-222 
    Details
    ISSN: 1573-1464
    Schlagwort(e): Acer platanoides ; Acer saccharum ; biodiversity ; competition ; invasive species ; regeneration ; understory
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Norway maple (Acer platanoidesis) is invasive in a natural stand in suburban Ithaca, NY. To determine the understory pattern and consequences of a Norway maple invasion, I compared density and species richness under Norway maples and sugar maples (Acer saccharum). Mean sapling density was significantly lower (P〈0.0027) under Norway maples (3.64/100 m2±1.6 SE) than under sugar maples (19.4/100 m2±4.4 SE). Mean sapling species richness was significantly lower (P〈0.0018) under Norway maples (0.7/32 m2±0.18 SE) than under sugar maples (2.6/32 m2±0.48 SE). Likewise, Norway maple regeneration is more frequent under sugar maples than sugar maple regeneration: 57% of sugar maple plots had Norway maple saplings while 0% of Norway maple plots had sugar maple saplings. Two significant plot effects were found for presence–absence: Norway maple saplings grow under Norway maples with a significantly lower frequency (P〈0.03) than under sugar maples; sugar maple saplings grow under Norway maples with a significantly lower frequency (P〈0.000) than under sugar maples. Across the site, Norway maple saplings were the most abundant (29 saplings for 480 m2). The success of Norway maple regeneration and the reductions in total stem density beneath Norway maples is most likely the result of its strong competitive abilities, notably its high shade tolerance and abundant seed crops.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010084421858
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  • 24
    Digitale Medien
    Digitale Medien
    Bifurcations in Spherical MHD Models (1998)
    Springer
    Studia geophysica et geodaetica 42 (1998), S. 320-327 
    Details
    ISSN: 1573-1626
    Schlagwort(e): MHD ; stability ; bifurcations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Geologie und Paläontologie , Physik
    Notizen: Abstract A series of numerical studies on the behaviour of magnetic fields and motions in a spherical body of an electrically conducting incompressible fluid have been carried out. The magnetic field was assumed to be maintained by a given electromotive force inside the body and to continue as a potential field in outer space. In view of the motion an external forcing was taken into account, and boundary conditions were considered which correspond to a stress-free surface. The stability of several steady states has been studied as well as the evolutions starting from unstable states. In this paper a configuration with a poloidal magnetic field and a differential rotation, both symmetric about the same axis, is considered. This configuration is stable only for sufficiently small Hartmann numbers but evolves, if disturbed, in the case of larger Hartmann numbers toward a non-axisymmetric state. In this case the well-known symmetrization effect of differential rotation in magnetic fields is destroyed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1023356720631
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  • 25
    Digitale Medien
    Digitale Medien
    Inventorying the fungi of Mexico (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 369-384 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; Mexican fungi ; estimations ; species numbers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Conservation of the vegetation, analysis of the knowledge of the diversity of fungi, new biological methods and estimates of the numbers of species of fungi that grow in Mexico are discussed. The great forest destruction that is occurring and the loss of fungal diversity in the country is seriously depleting total biodiversity, mainly in the tropics. Methods to establish the number of Mexican species of fungi are proposed based on an average of: (1) the numbers of fungal obligates of vascular plants and animals and of the saprobic species; (2) extrapolating the number of the British fungi to Mexico, taking the British mycota as the best known in the world; and (3) extrapolating to the country the number of species known to occur in the State of Veracruz (Mexico), the best known in the country. The average of these three calculations yields about 200 000 species of fungi for Mexico. Of these, only 3.5% are known, despite considerable progress having been made in the inventory of the country's fungi in the last 30 years. It is concluded that it is necessary to place more emphasis on alpha taxonomy, to train more specialists and to prepare monographs of several groups of fungi.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008833829473
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  • 26
    Digitale Medien
    Digitale Medien
    Peatswamp ecology and sustainable development in Borneo (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 651-671 
    Details
    ISSN: 1572-9710
    Schlagwort(e): tropical peatswamps ; peatlands ; conservation ; biodiversity ; Borneo
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract While tropical lowland peatswamp ecosystems are well-represented among the major forest formations of Borneo, they are rare outside South-East Asia. They are richly endowed with biological diversity, including the crocodile (Crocodylus porosus), which is a threatened species, and are characterized by their organic (histosol) soils that have developed recently, approximately within the past 5000 years. Their unique ecological features, as well as logistical difficulties in accessing and utilizing peatswamps, have not, however, deterred exploitation. Some of the tallest, most commercially desirable timber species, such as ramin (Gonystylus bancanus) have been harvested routinely in the peatswamp forests of Sarawak. Also, due to its primary location in coastal lowlands in close proximity to human activity, drained and reclaimed peatswamp land is desirable for development of highways, housing, and industrial and plantation estates. Ecological information is needed urgently by decision-makers and land-owners, who may be contemplating conversion of natural peatswamp ecosystems to other land uses, to undergird conservation policy and best management practices for the wise stewardship and sustainable development of this ecosystem. The paper provides an overview of peatswamp ecology with recommendations for avoiding or reducing potential ecological impacts associated with peatswamp development in Borneo, which include a moratorium on further development until a Borneo peatswamp survey and inventory as well as a holistic, multi-sectoral, integrated environmental assessment and planning procedure are completed; gazetting of pristine peatswamp forest parcels as totally protected areas; implementing highly restricted multiple-use policy that allows development only in degraded areas, and insuring protection of the critical hydrological role of peatswamps in providing fresh water supply for human use as an overriding criterion in assessing any development scheme.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008808519096
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  • 27
    Digitale Medien
    Digitale Medien
    Role of fungi in marine ecosystems (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 1147-1161 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; biogeography ; fungi ; marine ; nutrient cycling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Marine fungi are an ecological rather than a taxonomic group and comprise an estimated 1500 species, excluding those that form lichens. They occur in most marine habitats and generally have a pantropical or pantemperate distribution. Marine fungi are major decomposers of woody and herbaceous substrates in marine ecosystems. Their importance lies in their ability to aggressively degrade lignocellulose. They may be important in the degradation of dead animals and animal parts. Marine fungi are important pathogens of plants and animals and also form symbiotic relationships with other organisms. The effect of disturbances on marine fungi is poorly investigated. Keystone marine species may exist, especially in mutualistic symbioses. However, as many saprophytes appear to carry out the same function simultaneously, they may be functionally redundant. The need for a concerted effort to investigate the biodiversity and role of marine fungi globally and on as many substrata as possible is presented.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008823515157
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  • 28
    Digitale Medien
    Digitale Medien
    Management of biodiversity: natural resources and social institutions (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 1-6 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; decision making ; management ; natural resources ; social institutions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008874120543
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  • 29
    Digitale Medien
    Digitale Medien
    Biodiversity conservation in China: Legislation, Plans and Measures (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 819-837 
    Details
    ISSN: 1572-9710
    Schlagwort(e): action plan ; biodiversity ; database ; germplasm ; legislation ; nature reserve
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract China is one of the “megadiversity” countries with over 30,000 species of higher plants and 6347 species of vertebrates, including numerous endemic species and relict species. The vast territory, with its various climates and landforms have formed complex and manifold habitats and rich diversity of ecosystems. China is a signatory country to several international conventions and agreements related to biodiversity and has established a legislation framework for biodiversity conservation. State, interdepartmental, departmental plans related to biodiversity have been made, such as Chinas Agenda 21, the Chinese Country Study on Biological Diversity, the Chinese Biodiversity Conservation Action Plan, the Chinese Environmental Protection Action Plan, and the Guideline for Nature Reserve Development Planning in China (1996–2010). Great efforts have also been made to protect natural resources and the environment, including policies for in situ and ex situ conservation, ecological construction, scientific research, education and training, and international cooperation. However, under the high pressure of population and economy, severe contradiction exists between conservation and the exploitation of biodiversity. This paper describes such achievements and related problems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008890112636
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  • 30
    Digitale Medien
    Digitale Medien
    Rapid micro-evolution and loss of chromosomal diversity in Drosophila in response to climate warming (1998)
    Springer
    Evolutionary ecology 12 (1998), S. 829-838 
    Details
    ISSN: 1573-8477
    Schlagwort(e): biodiversity ; chromosomal polymorphism ; climate change ; Drosophila subobscura ; micro-evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Concern regarding the ecological impact of rapid global warming has encouraged research on climate-induced changes in biological systems. Critical problems, still poorly understood, are the potential for rapid adaptive responses and their genetic costs to populations. The O chromosomal polymorphisms of Drosophila subobscura have been monitored at a southern Palearctic locality experiencing sustained climate warming since the mid-1970s. Observations suggest that the population is rapidly evolving in response to the new environmental conditions, and has lost a significant amount of chromosomal diversity (18.3% in 16 years). These findings are consistent with results from another population of D. subobscura, which is also undergoing climate warming, and are in accord with what would be expected from latitudinal and seasonal patterns of the various inversions. In addition, data on the O chromosomal polymorphisms from other localities throughout t he range of this species suggest that other populations vary similarly.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006546616462
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  • 31
    Digitale Medien
    Digitale Medien
    Developing elite durum wheat landrace selections (composites) for Ethiopian peasant farm use: Raising productivity while keeping diversity alive (1998)
    Springer
    Euphytica 102 (1998), S. 323-328 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum turgidum ; farmers' varieties ; genetic diversity ; composite ; stability ; durum wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The Ethiopian peasant farms are characterized by highly varied micro-environments differing in characteristics such as topography, soil type, water, temperature and fertility. The bulk of the durum wheat planting material currently in use on these farms is largely represented by traditional farmers' varieties/landraces. These traditional farmers' varieties/landraces generally, are stable but low yielding, and often fail to adequately meet the level of productivity essential for production beyond subsistence level, unless they are enhanced to improve their competitiveness with modern varieties in respect to yield. Improving the productivity of landraces, while maintaining an appreciable level of genetic diversity is crucial to yield stability. This could be achieved by developing composites that are formed by bulking together three or more potentially high yielding spikes (agrotypes) that vary for various morphologic and agronomic characteristics, but due to their similarity in plant height, maturity, glume color and seed color give the composite a uniform field appearance like a modern variety.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1018360432426
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  • 32
    Digitale Medien
    Digitale Medien
    Spatial scale and the diversity of benthic cyanobacteria and diatoms in a salina (1999)
    Springer
    Hydrobiologia 401 (1999), S. 199-206 
    Details
    ISSN: 1573-5117
    Schlagwort(e): hypersaline ; microbial mat ; cyanobacteria ; diatom ; microbial richness ; biodiversity ; 16S rRNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We characterized the richness of benthic cyanobacteria and diatoms in a salina system using traditional and molecular biological methods. After determining the different morphotypes and 16S rRNA genes present in various localities within this hypersaline system, an analysis of the increase of organismal richness as a function of numbers of samples considered was carried out. We found that the spatial scales of sampling yielding significant increases in cumulative richness were those at which significant variations in environmental parameters (salinity, vertical microgradients) are known to exist, indicating that the presence of environmental gradients contributes to increased biodiversity. Additionally, we could use this type of cumulative analysis for the estimation, through asymptotic extrapolation, of the total richness of oxygenic phototrophs present in the entire salina system, and for the estimation of the average degree of dissemination of community members within the system. We found interesting differences between analyses based on morphotypes or 16S rRNA genes. The cumulative number of rRNA gene sequences exceeded that of morphotypes by more than two-fold. This indicates that many organisms possessing distinct 16S rRNA gene sequences could not be distinguished on the basis of morphology. Thus, some of the apparently widely distributed morphotypes may in fact conceal several ecologically independent genotypes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003702814150
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  • 33
    Digitale Medien
    Digitale Medien
    A comparative study of benthic nematodes in two Chinese lakes with contrasting sources of primary production (1999)
    Springer
    Hydrobiologia 411 (1999), S. 31-37 
    Details
    ISSN: 1573-5117
    Schlagwort(e): freshwater lakes ; nematodes ; species composition ; biodiversity ; trophic groups ; macrophytes ; phytoplankton
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Ecological studies on benthic nematodes were conducted in two small, shallow lakes in the middle Yangtze basin, China; Lake Houhu, where the main source of primary production is phytoplankton and Lake Biandantang where it is predominantly macrophytic in origin. Monthly sampling was carried out from April 1996 to March 1997. A total of 36 species of nematodes was found in Lake Houhu and 51 species in Lake Biandantang. The dominant trophic groups of nematodes were algophages in Lake Houhu and bacteriophages associated with omniphages and phytophages in Lake Biandantang. Community analyses based on K-dominance curves, Shannon-Wiener and Simpson diversity indices, demonstrate that the benthic nematodes are more diverse in Lake Biandantang than in Lake Houhu. The results suggest that the abundance of submerged vegetation is essential for maintenance of habitat heterogeneity and biodiversity of nematodes in shallow lakes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003835503175
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  • 34
    Digitale Medien
    Digitale Medien
    Clitellate diversity in Nationalstadsparken, an urban national park in Stockholm, Sweden (1999)
    Springer
    Hydrobiologia 406 (1999), S. 101-110 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Clitellata ; Oligochaeta ; Hirudinea ; biogeography ; biodiversity ; urban habitats
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract To increase the overall faunistic knowledge of Swedish Clitellata, a survey was performed in Nationalstadsparken, a mosaic of fresh and brackish waters, parklands alternating with remnants of natural biota, and areas of urban development, within the cities of Stockholm and Solna on the Baltic coast of Sweden (59° N, 18° E). One hundred and twenty-one species (113 Oligochaeta, 8 Hirudinea) were collected at 31 aquatic and 27 terrestrial or littoral localities; 49 species of Oligochaeta were found at the aquatic localities, 70 species at the terrestrial/littoral sites. Twenty-four species are new records for Sweden, and this urban national park thus features 64% of all non-marine clitellates known from the country. The result is consistent with a view that diversity is enhanced when human activities increase habitat complexity, even in areas in direct contact with a large city.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003747412063
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  • 35
    Digitale Medien
    Digitale Medien
    Diversity of invertebrate fauna in littoral of shallow Myczkowce dam reservoir in comparison with a deep Solina dam reservoir (1999)
    Springer
    Hydrobiologia 408-409 (1999), S. 203-210 
    Details
    ISSN: 1573-5117
    Schlagwort(e): dam reservoirs ; biodiversity ; littoral zone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This is the first assessment of bottom fauna in littoral of shallow dam reservoir Myczkowce (191 ha, 12 m deep) and deep Solina reservoir (2105 ha, 65 m deep). Both reservoirs were formed in the 1960s in Carpathian Mountains. The reservoirs differ much in terms of size, range and regime of water level changes, water exchange rate and temperature. Quantitative samples were taken monthly using Morduchaj-Boltovski cylindrical bottom sampler from 3 stations in Myczkowce and 4 stations in Solina reservoir. In Myczkowce, 8–14 taxonomic groups of invertebrates were found in each site. Numbers of littoral fauna incerased during the season. There was no strong dominance of any particular group during summer, while in spring and autumn there was a slight prevalence of Diptera larvae and Isopoda. Total numbers of fauna in littoral of Solina reservoir were almost 3 times lower than those in the Myczkowce littoral. Only 1–7 taxa (systematic groups) were found in each site, of Solina reservoir. The dominant groups were easily assessed: Diptera larvae (mainly Chironomidae) and, a subdominant group, Oligochaeta. In Myczkowce reservoir, the Shannon-Weaver index of biodiversity was high (0.4–0.95). The index in stations in Solina reservoir was much lower (0.05–0.7). In Myczkowce, the course of index of equitability corresponded closely with that of biodiversity. In Solina, it showed higher values than the Shannon-Weaver index. This may indicate that the potential biodiversity in this environment was utilised by the communities in high degree. In general, the invertebrate fauna of littoral zone of Myczkowce reservoir is richer, both in terms of numbers and diversity than that of Solina reservoir. The main cause of these differences is a different character of water level changes. In Myczkowce, these changes reach 2 m and have a short term character, while in Solina water level varies (up to 10 m) and remains low all winter, this causes destruction of littoral which has to form again next season.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1017015515507
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  • 36
    Digitale Medien
    Digitale Medien
    Spartina patens as a weed in Galician saltmarshes (NW Iberian Peninsula) (1999)
    Springer
    Hydrobiologia 415 (1999), S. 213-222 
    Details
    ISSN: 1573-5117
    Schlagwort(e): biological invasion ; biodiversity ; Spartina versicolor ; Spain
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Spartina patens (Gramineae) is an American coastal grass which grows in a wide range of coastal habitats in its native area. After it was discovered in some Galician wetlands two years ago, we undertook a regional survey whose preliminary results reveal that this grass is actually a rather common species in Southwestern Galicia, being present in several coastal habitats also. Nevertheless, it is in saltmarshes where it seems to compete more successfully, invading rush communities that have been traditionally harvested for cattle bedding. In many estuaries, it tends to form dense monospecific stands and could become a serious threat to high marsh plant diversity. In order to evaluate the impact of S. patens as an invasive weed in saltmarshes, we have performed a transect study, which seems to indicate that S. patens establishes preferentially in the upper marsh (but reaching higher coverages in the uppermost part of its altitudinal rank), where it has a significant negative effect on species diversity as well as on total cover of other species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003835201167
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  • 37
    Digitale Medien
    Digitale Medien
    Do body and fin form affect the abilities of fish to stabilize swimming during maneuvers through vertical and horizontal tubes? (1998)
    Springer
    Environmental biology of fishes 53 (1998), S. 365-371 
    Details
    ISSN: 1573-5133
    Schlagwort(e): Carassius auratus ; Metynnis hypsauchen ; Pterophyllum scalare ; goldfish ; angelfish ; silver dollar ; swimming ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Goldfish, Carassius auratus, silver dollar, Metynnis hypsauchen, and angelfish, Pterophyllum scalare were induced to swim through narrow vertical and horizontal tubes ranging in length from 0 to 20 cm (approximately 0 to 3 times total fish length, FL). The ability to stabilize the body while negotiating these confined spaces was quantified as (1) the minimum width of vertical (wv) and horizontal (wh) tubes traversed, where width is the smaller cross-sectional dimension of the tube, (2) the ratio wv/wh, and (3) transit speed through the tubes. Tube width was expressed as relative width, obtained by dividing tube width by fish length. Minimum relative widths traversed increased from 0.15 to 0.19 in the order silver dollar 〉 angelfish 〉 goldfish for vertical tubes and from 0.17 to 0.18 in the order goldfish=silver dollar 〉 angelfish for horizontal tubes. wv/wh increased from 0.91 to 1.10 in the order silver dollar=angelfish 〉 goldfish. Minimum tube widths generally increased with tube length for vertical tubes. Although significant differences in relative minimum widths among species were found, these were small. In contrast, for horizontal tubes, there was no significant effect of tube length on minimum tube width for any species. Large differences were found in transit speed. Transit speed generally decreased as the tube length increased. The slope of the relationship between transit speed and tube length varied among species generally increasing from − 0.41 to − 1.16 for horizontal tubes in the order goldfish 〉 silver dollar 〉 angelfish and from − 0.42 to − 1.07 in the order silver dollar 〉 goldfish 〉 angelfish for vertical tubes. As a result, goldfish usually took longest to traverse tubes of zero length but the shortest time to traverse the longest tubes. In contrast, angelfish traversed short tubes in the least time and long tubes in the greatest time. Deeper bodied angelfish swam slowly and traversed tubes with difficulty because they required experience during each trial to replace median and paired fin with body and caudal fin swimming. According to our data, goldfish were best able to swim in confined spaces.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1007414911734
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  • 38
    Digitale Medien
    Digitale Medien
    Pattern of land mosaics affecting butterfly assemblage at Mt Ikoma, Osaka, Japan (1999)
    Springer
    Ecological research 14 (1999), S. 105-118 
    Details
    ISSN: 1440-1703
    Schlagwort(e): biodiversity ; butterfly ; conservation ; landscape ecology ; Quercus forests
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: We studied the effects of habitat mosaics on butterfly assemblage on multiple spatial scales: landscape, landscape element, local habitat, and microhabitat, based on the transect counts conducted along a 3.84 km route. The transect route, including 21 local habitats, passed through two distinct areas: 1.65 km of a secondary deciduous Quercus forest and the grove of a shrine in Hiraoka, and 2.19 km of a mosaic of secondary deciduous Quercus forest, grassland, and farmland in Narukawa. The diversity of the landscape elements and species richness were higher in Narukawa than in Hiraoka; the landscape mosaic enhanced the species richness in Narukawa. However, the diversity indices and specialist species (univoltine tree feeder) were decreased in this mosaic landscape. The species richness at local habitats was also increased by the mosaic of microhabitats, such as the herbaceous layer, glade, and mantle in the local habitats, whereas it was decreased by an abundant shrub layer. The ratios of species richness to abundance in the local habitats were lower than expected based on random sampling from the total of Hiraoka and Narukawa. This means that local assemblages were non-random samples from an assemblage on the landscape or regional scale, and were made up by the process of habitat selection of butterfly species in the assemblages on the landscape or regional scale. For conservation of butterfly assemblages, we recommend that woodlands should be kept without fragmentation, but with glades or small grasslands, and with clearance of the shrub layer along the path.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1440-1703.1999.00287.x
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  • 39
    Digitale Medien
    Digitale Medien
    Diversity in specific gravity and water content of wood among Bornean tropical rainforest trees (1999)
    Springer
    Ecological research 14 (1999), S. 211-224 
    Details
    ISSN: 1440-1703
    Schlagwort(e): biodiversity ; Indonesia ; tropical rainforests ; wood specific gravity ; wood water contents
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Wood properties were measured for trees in lowland dipterocarp forests in West Kalimantan. In 1993 and 1994, 353 samples of 286 species were collected from trunk base of trees of approximately 5 cm in diameter, and the specific gravities (SG: oven dry weight/fresh volume) and water contents of wood including bark were measured. The SG of each species ranged from 0.21 to 0.84, and the mean ± SD was 0.53 ± 0.13. The wide range of SG suggests that the forest had a high diversity in wood properties. The most dominant and diversified genus in this area was Shorea, and the SG of 15 species varied from 0.21 to 0.71. The range covered SG of pioneer (six Macaranga, 0.29–0.43) and small trees in primary forests (nine Eugenia and 10 Xanthophyllum, 0.55–0.77). The SG average for tree species of secondary forests of 2–6 years old was 0.31. It was significantly smaller than that of primary forests (0.58). In a primary dipterocarp forest plot, light-wood species grew faster in diameter than heavy-wood species. Water content ranged from 0.26 to 0.76. Heavy wood had low water content. Among light-wood species, some (Shorea, Artocarpus) had low water contents and others (Ficus) had high water contents. Some riverine trees also had high water contents. These wood properties appear strongly related to the life history of trees and successional stage.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1440-1703.1999.143301.x
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  • 40
    Digitale Medien
    Digitale Medien
    Nutrient cycling and growth in forest ecosystems of south western Australia: Relevance to agricultural landscapes (1999)
    Springer
    Agroforestry systems 45 (1999), S. 215-244 
    Details
    ISSN: 1572-9680
    Schlagwort(e): biodiversity ; disturbance ; nitrogen ; phosphorus ; resilience ; resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Nutrient and hydrologic cycles in harvested native forests in southern Australia are largely balanced. For example, we have little or no evidence of any decline in nutrient capital or availability in harvested forests. Short-term and small-scale reductions in evapotranspiration due to loss of leaf area after harvesting are adequately balanced at the landscape scale by large areas of regenerating or older-age forest. In contrast, agricultural systems on similar soils are a) dependent on large inputs of fertilisers to maintain growth and b) frequently subject to increasing salinity and waterlogging or other forms of degradation. The large-scale replacement of long-lived communities of perennial and often deep- rooting native species with annual crops or other communities of shallow-rooting species might be better managed within the framework of knowledge developed from studies of native plant communities. However, application of such a mimic concept to systems of low natural productivity is limited when agricultural systems require continued high productivity. Nonetheless, the mimic concept may help in developing sustainable management of agriculture on marginal lands, and contribute to the nutritional resilience of agroecosystems. Relevant characteristics for mimic agroecosystems in south western Australia include: high species diversity, diversity of rooting attributes, utilisation of different forms of nutrients (especially of N and P) in space and time, and the promotion of practices which increase soil organic matter content.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006267604313
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  • 41
    Digitale Medien
    Digitale Medien
    Rotifera of some freshwater habitats in the floodplain of the River Nan, northern Thailand (1998)
    Springer
    Hydrobiologia 287-388 (1998), S. 27-33 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Rotifera ; biodiversity ; floodplain ; taxonomy ; Thailand
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A survey of 11 freshwater habitats in the floodplain of the River Nan, northern Thailand was carried out during April and September 1996. The rotifer samples were collected qualitatively from paddy fields, ponds, canals and reservoirs, using a 60 μm mesh net. One hundred and eighteen species were identified, four (Lepadella quinquecostata (Lucks), Macrochaetus danneeli Koste & Shiel, Testudinella ahlstromi Hauer and T greeni Koste) of which are new to Thailand and one (L. quinquecostata) is new to Asia. The numbers of species found in two localities are relatively high, with 86 and 73 rotifer taxa. Most of the species recorded are common, cosmopolitan or pantropical and warm-stenotherms. The occurrence of a species previously considered endemic to Australia, M. danneeli provides more evidence illustrating a relation between the rotifer faunas of southeast Asia and Australia. Comments are presented on some insufficiently known taxa in particular on the new records for Thailand.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1017044400183
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  • 42
    Digitale Medien
    Digitale Medien
    Ecological genetics of Brachionus sympatric sibling species (1998)
    Springer
    Hydrobiologia 287-388 (1998), S. 373-384 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Rotifera ; zooplankton ; cyclical parthenogens ; coastal lagoons ; environmental heterogeneity ; allozymes ; mating behavior ; sexual reproduction ; speciation ; biodiversity ; seasonal specialization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In this paper we review previous studies on sympatric Brachionus populations in Torreblanca Marsh as a model of evolutionary and ecological relationships between closely related species. The marsh is a wetland on the Mediterranean coast of Spain with high spatial and temporal heterogeneity. Allozyme and morphometric analysis showed that Brachionus group plicatilis (formerly, Brachionus plicatilis and currently split into B. plicatilis and B. rotundiformis) was composed of three groups of genotypes with no evidence of gene flow between them (B. plicatilis, B. rotundiformis SM and B. rotundiformis SS). Correlations between seasonal and spatial distributions, on one hand, and temperature and salinity, on the other hand, were consistent with the results of experimental studies on population dynamics. Accordingly, B. plicatilis is a euryhaline, low temperature group; B. rotundiformis SM is adapted to high temperature and low salinity conditions; and B. rotundiformis SS is adapted to high temperature and high salinity conditions. The groups had different mictic responses to density, salinity and temperature, which can be explained to some extent as an adaptive escape response, given their different ecological preferences. These differences imply a partial ecological barrier to male–female encounter between groups. Mating experiments showed that most copulations occurred within a group. B. plicatilis has a mating recognition system different from those of either B. rotundiformis SM or SS, whereas the two B. rotundiformis groups had partially differentiated mating preferences. Cross-mating experiments performed in the laboratory failed to produce any detectable hybrids. We conclude that three sympatric sibling species inhabit Torreblanca Marsh. The remarkable association between genetic differences among clonal groups and their ecological preferences, mixis response and mating behavior is hypothesized to play a role in stabilizing sympatry, and gives insight into the evolution of genetic divergence and speciation in rotifers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1017083820908
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  • 43
    Digitale Medien
    Digitale Medien
    Seeding date effects on rough rice yield and head rice and selection for stability (1998)
    Springer
    Euphytica 102 (1998), S. 151-161 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Oryza sativa ; head rice ; seeding date ; rice ; rough rice yield ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The rice (Oryza sativa L.) crop in Arkansas is seeded from late March through early June each year. Farmers need new rice cultivars that not only produce both high rough rice yields and high head rice across this range of seeding dates but do so consistently. Thus, a seeding date study was conducted during 1994 and 1995 at Stuttgart, Arkansas, to study seeding date effects on rough rice yield and head rice and selection for stability. Fourteen rice cultivars were seeded at five dates ranging from late March through mid-June. Kang's yield-stability statistic was used to select cultivars for both high rough rice yields and high head rice as well as stability for both traits. Plant stands from March seedings of each year were significantly lower than for the later seeding dates. Maturity (days to 50 percent heading) was extended at the early seeding dates. Some rice cultivars, such as ‘LaGrue’, had lower and more variable head rice when seeded early. In the June seeding dates each year, ‘Kaybonnet’ produced rough rice yields that were more consistent with yields when planted at the earlier planting dates. ‘Bengal’, ‘Cypress’, ‘Kaybonnet’, and ‘Newbonnet’ were cultivars selected by Kang's stability statistic, which was targeted to select cultivars with stable, high rough rice yields and stable, high head rice. The validity of using Kang's yield-stability statistic for cultivar selection is also evident empirically by the adaptation and wide use of these four cultivars by southern U.S. rice producers. These results indicate that seeding date studies and stability analyses would be useful tools for rice breeders to identify cultivars that will be readily adapted and grown by rice producers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1018344615296
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  • 44
    Digitale Medien
    Digitale Medien
    Breeding for yield and quality in durum wheat (1998)
    Springer
    Euphytica 100 (1998), S. 15-18 
    Details
    ISSN: 1573-5060
    Schlagwort(e): biparental mating ; stability ; Triticum durum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Three populations of an intervarietal durum wheat cross IWP5308/PDW208, F5, F5BIP1 (population derived after intermating in F2) and F5BIP2 (population derived after intermating in BIPF1), were evaluated under three different agronomic environments for mean performance and stability of genotypes for grain yield, yield components and protein content. Though the biparental progenies indicated a higher mean performance, they did not differ significantly from progenies of the pedigree method for almost all characters. The biparental progenies, however, produced a higher number of stable genotypes for grain yield per plant, grains per ear and protein content. The F5 population had a higher number of stable genotypes for 1000 grain weight and number of tillers per plant. The BIP progenies also had a higher number of genotypes with above average mean performance, and many were significantly higher than the checks WH896 and WH542, compared with F5 progenies. Hence, in spite of high G x E interactions, the use of cycles of biparental mating and selection of top yielding lines on the basis of yield components can enable selection of stable genotypes with high protein content. Number of tillers per plant and 1000 grain weight were the yield component characters which made maximum contribution to phenotypic stability of the genotypes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1018335402010
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  • 45
    Digitale Medien
    Digitale Medien
    Stability of performance of tetraploid wheat landraces in the Ethiopian highland (1998)
    Springer
    Euphytica 102 (1998), S. 301-308 
    Details
    ISSN: 1573-5060
    Schlagwort(e): adaptation ; correlations ; genotype-environment interaction ; landraces ; performance ; stability ; tetraploid wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Plant breeding has always been concerned with genotype-environment interaction. Normally high and stable performance are desirable attributes of cultivars. However, this is practically difficult to achieve where environmental variations are high and unpredictable and significant genotype-environment interactions occur. Stability of performance of 13 landraces evaluated at 4 different locations for 3 years in the highlands of Ethiopia was investigated. The testing locations have different climatic and edaphic conditions providing the conditions necessary for the assessment of stability. Stability parameters like b, s2d, s2, r2 and cv which are in common use were employed. Grain yield and 1000-kernel weight were the agronomic traits considered for the stability analysis. There were differences in the ranks of genotypes across the locations. Significant main environmental as well as interaction effects were observed showing the importance of genotype-environment interaction in both traits. Many of the landraces evaluated are rated as stable for these traits within the environmental conditions prevailing in these highland locations. Genotypes with specific adaptation to poor and favourable conditions were also identified. Certain genotypes showed similar manners of adaptation and stability for both of the traits. Grain yield showed low correlations with the stability parameters showing the possibility of attaining high yield and stability. Correlations between the stability parameters were mainly positive and significant for grain yield. Only a few of these correlations were found to be significant for kernel weight. The good adaptability of landraces should be exploited in the improvement of their yield potential.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1018361309207
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  • 46
    Digitale Medien
    Digitale Medien
    Microbial ribulose 1,5-bisphosphate carboxylase/oxygenase: A different perspective (1999)
    Springer
    Photosynthesis research 60 (1999), S. 1-28 
    Details
    ISSN: 1573-5079
    Schlagwort(e): biodiversity ; carboxylase ; genetic selection ; photosynthesis ; regulation ; specificity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Marine and terrestrial photosynthetic and chemoautotrophic microorganisms assimilate considerable amounts of carbon dioxide. Like green plastids, the predominant means by which this process occurs is via the Calvin-Benson-Bassham reductive pentose phosphate pathway, where ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) plays a paramount role. Recent findings indicate that this enzyme is subject to diverse means of control, including specific and elaborate means to guarantee its high rate and extent of synthesis. In addition, powerful and specific means to regulate Rubisco activity is a characteristic feature of many microbial systems. In many respects, the diverse properties of microbial Rubisco enzymes suggest interesting strategies to elucidate the molecular basis of CO2/O2 specificity, the ‘holy grail’ of Rubisco biochemistry. These systems thus provide, as the title suggests, ‘different perspectives’ to this fundamental problem. These include vast possibilities for imaginative biological selection using metabolically versatile organisms with well-defined genetic transfer capabilities to solve important issues of Rubisco specificity and molecular control. This review considers the major issues of Rubisco biochemistry and regulation in photosynthetic microoganisms including proteobacteria, cyanobacteria, marine nongreen algae, as well as other interesting prokaryotic and eukaryotic microbial systems recently shown to possess this enzyme.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006211417981
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  • 47
    Digitale Medien
    Digitale Medien
    The Gyratrix hermaphroditus species complex (Kalyptorhynchia: Polycystididae) in marine habitats of eastern Australia (1998)
    Springer
    Hydrobiologia 383 (1998), S. 287-298 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Platyhelminthes ; Gyratrix species-complex ; Australia ; biodiversity ; chromosomal evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A karyological and morphological analysis of 97 specimens from eastern Australia belonging to the Gyratrix hermaphroditus species complex was performed. Based on karyotype and on details of sclerotized structures of the copulatory organ, the existence of at least eight sibling species in eastern Australia could be recognised. Some of the siblings have a wide distribution across eastern and northern Australia. Populations of wide-ranging species often showed degrees of karyological and morphological differentiation. The diversity of the group is particularly high in tropical Australia. Distribution of siblings appears to be affected by ecological and physical barriers, and determined by sediment texture.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003456102035
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  • 48
    Digitale Medien
    Digitale Medien
    Fifty years of hydrobiological research in India (1998)
    Springer
    Hydrobiologia 384 (1998), S. 267-290 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Benthos ; biodiversity ; biomonitoring ; community ecology ; ecotoxicology ; fisheries ; macrophytes ; microbiology ; phytoplankton ; population ecology ; thermal springs ; zooplankton
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The paper provides an overview of the developments in hydrobiological studies in India during the past fifty years, and links them with a historical perspective of the pre-independence studies. Hydrobiological studies which were well developed in the beginning of this century, gained momentum soon after independence as all kinds of aquatic habitats were investigated for the assessment, conservation and optimum utilization of inland fishery resources of the country. However, the environmental issues which dominated since the 1972 Stockholm Conference, and growing realization of the problem of water pollution, resulted in a rapid proliferation of hydrobiological studies which tend to focus on correlation between the distribution of various organisms and degree of water pollution or the effects of various organic and inorganic pollutants. A sampling of published literature reveals that long-term, analytical and experimental studies of the whole ecosystems (natural or experimental), and studies of population interactions, biomanipulation, food chain dynamics, and energy flows are wholly lacking. The paper calls for the strengthening of field and laboratory facilities, and establishment of regional and national institutes of aquatic ecology which will be necessary for the management of both the water quality and aquatic biological resources for sustainable development.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003280426677
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  • 49
    Digitale Medien
    Digitale Medien
    Dissolved oxygen and thermal regimes of a Ugandan crater lake (1998)
    Springer
    Hydrobiologia 385 (1998), S. 201-211 
    Details
    ISSN: 1573-5117
    Schlagwort(e): hypoxia ; anoxic hypolimnion ; volcanic crater lake ; stratification ; productivity ; heat budget ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This paper quantifies the temporal pattern of thermal stratification and deoxygenation in Lake Nkuruba, a small (3 ha), deep (maximum depth = 38 m) crater lake in western Uganda. Dissolved oxygen penetrated to an average depth of 9 m and a maximum depth of 15 m below which the lake was permanently anoxic over the 2 years of study. Although surface oxygen levels were correlated with both surface water temperature and rainfall, seasonal cycles of dissolved oxygen were not well-defined and may have been obscured by the high frequency of short-term fluctuations and by inter-annual variations caused by shifts in rainfall. Surface water temperature averaged 23.3±0.7 °C (S.D.) and varied directly with air temperature. Both diurnal changes and top-bottom temperature differentials were small averaging 1.7±0.7 °C and 1.6±0.8 °C, respectively. Thermal stability ranged from 101.3 to 499.9 g-cm cm-2 and was positively related to surface water temperature suggesting that this small protected lake responds rapidly to short-term meteorological changes. Because contribution to the annual heat exchange cycle was confined to upper waters, the lake's annual heat budget was low, 1,073.8 cal cm-2 yr-1. However, net primary productivity was relatively high averaging 1.3 g C m-2d-1. The region where Lake Nkuruba is situated experienced a very strong earthquake (6.2 on the Richter scale) on 4 February, 1994. Subsequently, water levels dropped markedly in the lake, falling 3.14 m over a 5-month period.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003527016384
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  • 50
    Digitale Medien
    Digitale Medien
    Dissolved oxygen and thermal regimes of a Ugandan crater lake (1998)
    Springer
    Hydrobiologia 385 (1998), S. 201-211 
    Details
    ISSN: 1573-5117
    Schlagwort(e): hypoxia ; anoxic hypolimnion ; volcanic crater lake ; stratification ; productivity ; heat budget ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This paper quantifies the temporal pattern of thermal stratification and deoxygenation in Lake Nkuruba, a small (3 ha), deep (maximum depth = 38 m) crater lake in western Uganda. Dissolved oxygen penetrated to an average depth of 9 m and a maximum depth of 15 m below which the lake was permanently anoxic over the 2 years of study. Although surface oxygen levels were correlated with both surface water temperature and rainfall, seasonal cycles of dissolved oxygen were not well-defined and may have been obscured by the high frequency of short-term fluctuations and by inter-annual variations caused by shifts in rainfall. Surface water temperature averaged 23.3±0.7 °C (S.D.) and varied directly with air temperature. Both diurnal changes and top-bottom temperature differentials were small averaging 1.7±0.7 °C and 1.6±0.8 °C, respectively. Thermal stability ranged from 101.3 to 499.9 g-cm cm-2 and was positively related to surface water temperature suggesting that this small protected lake responds rapidly to short-term meteorological changes. Because contribution to the annual heat exchange cycle was confined to upper waters, the lake's annual heat budget was low, 1,073.8 cal cm-2 yr-1. However, net primary productivity was relatively high averaging 1.3 g C m-2d-1. The region where Lake Nkuruba is situated experienced a very strong earthquake (6.2 on the Richter scale) on 4 February, 1994. Subsequently, water levels dropped markedly in the lake, falling 3.14 m over a 5-month period.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003527016384
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  • 51
    Digitale Medien
    Digitale Medien
    Stability and resilience in benthic macroinvertebrate assemblages (1999)
    Springer
    Hydrobiologia 403 (1999), S. 123-133 
    Details
    ISSN: 1573-5117
    Schlagwort(e): disturbance ; stability ; resilience ; Trichoptera ; Ephemeroptera ; Psychomyia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Benthic macroinvertebrate assemblages of Bushkill Creek, Northampton County, PA were studied at the same site during the 1970s (11 dates) and 1990s (8 dates) to evaluate stability and resilience. In the 1970s, a Surber sampler was used, and in the 1990s, a Hess sampler. Assemblages appeared stable over a wide range of environmental stresses with the exception of 1994–1995 when total numbers and total Trichoptera decreased. Taxa richness and EPT indices varied little in 1994–1995 from other sampled years. By July 1996, all metrics (Trichoptera numbers, total numbers, taxa richness, EPT index, Bray-Curtis Index) resembled the 1970s exception for lower wet weight. Bray-Curtis indices and taxa composition were similar in July 1972 and July 1996, suggesting assemblage stability over 25 years. The Trichoptera, Psychomyia (Psychomiidae) and Leucotrichia (Hydroptilidae), decreased during the 1990s and never rebounded to 1970s numbers. During winter 1994, the coldest temperatures and greatest cumulative snowfall occurred in the region. These conditions probably stressed the assemblage with low temperatures, anchor/frazil ice and ice break-up. The assemblage was then exposed to four bankful floods in winter/spring 1994 and five bankful floods in winter/spring 1996. Recovery time following these multiple disturbances was 27 months. Previous recovery times from winter and flood disturbances were considerably shorter (2–5 months). The 1990s recovery time (5–9 times previusly recorded) for this assemblage was apparently extended by multiple physical disturbances, outside the predicted range. The assemblages had not been previously exposed to such severe conditions and, therefore, recovery time was extended. Despite severe weather conditions, the assemblage recovered and exhibited both stability and resilience in its return to an assemblage similar to the 1970s.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003711928980
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  • 52
    Digitale Medien
    Digitale Medien
    Ecological genetics of Brachionus sympatric sibling species (1998)
    Springer
    Hydrobiologia 387-388 (1998), S. 373-384 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Rotifera ; zooplankton ; cyclical parthenogens ; coastal lagoons ; environmental heterogeneity ; allozymes ; mating behavior ; sexual reproduction ; speciation ; biodiversity ; seasonal specialization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In this paper we review previous studies on sympatric Brachionus populations in Torreblanca Marsh as a model of evolutionary and ecological relationships between closely related species. The marsh is a wetland on the Mediterranean coast of Spain with high spatial and temporal heterogeneity. Allozyme and morphometric analysis showed that Brachionus group plicatilis (formerly, Brachionus plicatilis and currently split into B. plicatilis and B. rotundiformis) was composed of three groups of genotypes with no evidence of gene flow between them (B. plicatilis, B. rotundiformis SM and B. rotundiformis SS). Correlations between seasonal and spatial distributions, on one hand, and temperature and salinity, on the other hand, were consistent with the results of experimental studies on population dynamics. Accordingly, B. plicatilis is a euryhaline, low temperature group; B. rotundiformis SM is adapted to high temperature and low salinity conditions; and B. rotundiformis SS is adapted to high temperature and high salinity conditions. The groups had different mictic responses to density, salinity and temperature, which can be explained to some extent as an adaptive escape response, given their different ecological preferences. These differences imply a partial ecological barrier to male–female encounter between groups. Mating experiments showed that most copulations occurred within a group. B. plicatilis has a mating recognition system different from those of either B. rotundiformis SM or SS, whereas the two B. rotundiformis groups had partially differentiated mating preferences. Cross-mating experiments performed in the laboratory failed to produce any detectable hybrids. We conclude that three sympatric sibling species inhabit Torreblanca Marsh. The remarkable association between genetic differences among clonal groups and their ecological preferences, mixis response and mating behavior is hypothesized to play a role in stabilizing sympatry, and gives insight into the evolution of genetic divergence and speciation in rotifers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1017083820908
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  • 53
    Digitale Medien
    Digitale Medien
    Rotifera of some freshwater habitats in the floodplain of the River Nan, northern Thailand (1998)
    Springer
    Hydrobiologia 387-388 (1998), S. 27-33 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Rotifera ; biodiversity ; floodplain ; taxonomy ; Thailand
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A survey of 11 freshwater habitats in the floodplain of the River Nan, northern Thailand was carried out during April and September 1996. The rotifer samples were collected qualitatively from paddy fields, ponds, canals and reservoirs, using a 60 μm mesh net. One hundred and eighteen species were identified, four (Lepadella quinquecostata (Lucks), Macrochaetus danneeli Koste & Shiel, Testudinella ahlstromi Hauer and T greeni Koste) of which are new to Thailand and one (L. quinquecostata) is new to Asia. The numbers of species found in two localities are relatively high, with 86 and 73 rotifer taxa. Most of the species recorded are common, cosmopolitan or pantropical and warm-stenotherms. The occurrence of a species previously considered endemic to Australia, M. danneeli provides more evidence illustrating a relation between the rotifer faunas of southeast Asia and Australia. Comments are presented on some insufficiently known taxa in particular on the new records for Thailand.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1017044400183
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  • 54
    Digitale Medien
    Digitale Medien
    Transforming the Integrated Conservation and Development Project (ICDP) Approach: Observations from the Ranomafana National Park Project, Madagascar (1998)
    Springer
    Journal of agricultural and environmental ethics 11 (1998), S. 17-47 
    Details
    ISSN: 1573-322X
    Schlagwort(e): biodiversity ; buffer zone ; conservation ; development ; ethics ; international aid ; Madagascar ; national parks ; protected areas ; slash-and-burn
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Philosophie
    Notizen: Abstract Preservation of the biological diversity and ecosystems in protected areas can be achieved through projects linking conservation of the protected areas with improved standards of living for resident peoples within surrounding buffer zones. This is the hypothetical claim of the integrated conservation and development project (ICDP) approach to protected area management. This paper, based on several years of experience with the Ranomafana National Park Project in Madagascar, questions the major assumptions of this approach from ethical and practical perspectives. The four basic strategies available to ICDPs – protected areas, buffer zones, compensation, and economic development – are analyzed and shown to be deficient or untested in the case of Ranomafana. Recommendations are made to explore conservation models other than the western conception of the national park, to modify the notion of a buffer zone outside the protected area, to redistribute money or other resources directly to the poor people living in and around the protected areas, and to eliminate the middle men in the development business. An appeal is made to focus on local education, organization and discipline in order to promote self-determination and self-reliance among resident peoples of protected areas. The paper argues that a public works program, similar to the Roosevelt administration's Civilian Conservation Corps of the 1930s, funded through a hard-currency endowment or other innovative financing mechanism, should be tried as a replacement for the currently questionable ICDP approach at Ranomafana.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1007796628731
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  • 55
    Digitale Medien
    Digitale Medien
    Procedures for the characterisation of bioaerosol particles. Part I: aerosolisation and recovery agent effects (1999)
    Springer
    Aerobiologia 15 (1999), S. 267-280 
    Details
    ISSN: 1573-3025
    Schlagwort(e): aerosolisation effects ; bioaerosol ; bioaerosol sampling ; effects of recovery agents ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The sampling and assay of bioaerosols are important ina number of industrial and health-care applications. Airborne microorganisms are notoriously difficult toenumerate accurately under such conditions and nosingle procedure is suitable for all applications. Problems are compounded by the differences in assaymethod or sampler type selected, making theinterpretation of results difficult.Understanding the airborne behaviour of microorganismsover a range of environmental conditions is vital ifprocedures are to be defined and recommended for theassessment of bioaerosols. Microorganisms that arerobust over a wide range of conditions are ideal astracer particles. Unfortunately, the large majorityof non-fungal bioaerosols are susceptible to damage. A predictable assessment procedure is required whichwill not affect the viability of the collectedsample. This paper examines how aerosolisation may affect the characteristics of two speciesof microorganism (Pseudomonas fluorescens andMS2 coliphage). It forms part of a larger programmeto develop standards for the assessment of biologicalparticles. The aim of the work was to develop procedures toexamine the effects of aerosolisation onmicroorganisms, with particular reference topre-aerosolisation protocol (spray suspension age) andpost-sampling handling protocol (aerosol age incollection solution). These procedures were then usedto examine the effect of recovery agents, addedto the spray suspension prior to aerosolisation, onthe culturability of E.coli. Aerosolisation reduces the culturability of P. fluorescensand the viability of viability of MS2coliphage. Pre-sampling and post-collection handlingand storage of these aerosolised microorganisms werealso found to have an effect. This and earlierstudies have shown that the culturable fraction ofmicroorganisms can be affected by the same factorsdescribed above. Of five microorganisms tested so farin the main programme, only Penicillium expansumspores were shown to be robust and stable with aconstant culturable fraction. Therefore, recommendinga particular microorganism (apart from P. expansum) as an airborne biological standard foraerosol studies is not advised. It is recommendedthat a microorganism, representative of the envisagedapplication, be characterised it in terms of theaerosolisation parameters, storage time and conditionsin the manner reported in this study. This can beachieved using the experimental equipment described.The addition of 0.1 mM concentrations of the sugarsinositol, trehalose and raffinose to spray suspensionsof Escherichia coli, prior to aerosolisation,made no significant difference to the culturablefraction of the aerosol.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1007638711384
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  • 56
    Digitale Medien
    Digitale Medien
    Vertebrate invaders and their ecological impacts in Chile (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 1427-1445 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biological invasions ; invaders ; vertebrates ; biodiversity ; South America
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The South American country of Chile has been subjected to relatively few invasions in historic times. In comparison to the ca 610 vertebrate species found in continental Chile, only 24 species (3.9%) have invaded the country. Except for two bird and two or three mammal species that expanded their range and crossed the Andean Ranges from Argentina, the remaining 20 species were all introduced, or aided, by humans. Of the 24 invader species that currently occur in Chile, 11 (46%) were first introduced in central Chile, two (8%) in the northern part of the country, nine (38%) in the southern part, and two (8%) in Juan Fernández Archipelago. For ten (42%) of those species there is no information about their effects on the native flora, vegetation, or fauna. For eight species (33%), the information regarding the effects of the invaders is anecdotal. For six species (25%), there is adequate quantitative documentation available on their effects. Of a total of seven convincingly repo rted cases, two involve positive effects (increase in the prey base for native predators) and five have negative effects, of which three are on native vegetation and the remaining two on native fauna.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008825802448
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  • 57
    Digitale Medien
    Digitale Medien
    Amazonian biodiversity: assessing conservation priorities with taxonomic data (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 1577-1587 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; Amazonia ; geographic information system (GIS) ; museum collections ; species diversity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Data from 3991 records of museum collections representing 421 species of plants, arthropods, amphibians, fish, and primates were analyzed with GIS to identify areas of high species diversity and endemism in Amazonia. Of the 472 1 × 1° grid cells in Amazonia, only nine cells are included in the highest species diversity category (43–67 total species) and nine in the highest endemic species diversity category (4–13 endemic species). Over one quarter of the grid cells have no museum records of any of the organisms in our study. Little correspondence exists between the centers of species diversity identified by our collections-based data and those areas recommended for conservation in an earlier qualitative study of Amazonian biodiversity. Museum collections can play a vital role in identifying species-rich areas for potential conservation in Amazonia, but a concerted and structured effort to increase the number and distribution of collections is needed to take maximum advantage of the information they contain.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008889803319
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  • 58
    Digitale Medien
    Digitale Medien
    Enhancing the biodiversity of Scotland's forest resource through the development of a network of forest habitats (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 179-192 
    Details
    ISSN: 1572-9710
    Schlagwort(e): forest ; biodiversity ; habitat network
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Scottish Natural Heritage, the statutory conservation agency, is considering the desirability and feasibility of developing a network of woodland habitats to redress the long term trend of fragmentation and isolation. Woodland conservation has long been based on site protection, but recent changes in policy, attitude and practice have opened up the possibility of recreating native forest cover on a much larger scale. The ECONET approach appears to have much to offer as the basis for enhancing the biodiversity of Scotland's forest resource. A network could be developed from existing woods to form a Scotland-wide network of Core Forest Areas and major landscape links, largely associated with major valleys. To achieve this, existing concentrations of woodland would be extended into poorly wooded districts. Many vulnerable wildlife species are likely to benefit, and there would be other benefits for recreation, landscape and timber production.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008832401731
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  • 59
    Digitale Medien
    Digitale Medien
    Changes in aquatic plant communitieson the island of Valaam due to invasion by the muskrat Ondatra zibethicus L.(Rodentia, Mammalia) (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 673-690 
    Details
    ISSN: 1572-9710
    Schlagwort(e): muskrat introduction ; Ondatra zibethicus L. ; freshwater macrophyte communities ; biodiversity ; ecosystem stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Muskrat invaded Valaam Island (Northern part of European Russia) in the 1970s. Aquatic plant communities of 1962 and 1993 were compared on the same plots. Quantitative changes were tested with the help of jack-knifing estimates of most known inventory (α-) diversity indicators. Qualitative transformations were assessed using β-diversity values. The results demonstrated substantially more discriminant ability of diversity measures than classical methods of mathematical statistics. All of the α-diversity values declined synchronously without exception. Species composition also changed greatly and those species which turn out to be more resistant to muskrat grazing became the main dominant plants. The activity of Ondatra became the over-riding ecological factor connecting the littoral plant communities of the Valaam. It is concluded that the sustainability of this ecosystem was damaged by muskrat's invasion and that the role of muskrat should not be underestimated when studying the ecology of freshwater littoral communities.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008860603166
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  • 60
    Digitale Medien
    Digitale Medien
    Stability of butterfly assemblages in relation to the level of numerical resolution and altitude (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 967-979 
    Details
    ISSN: 1572-9710
    Schlagwort(e): altitude ; biodiversity ; demographic stability ; Lepidoptera ; northern Spain
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Quick studies on biodiversity are frequently used in conservation assessments. Conclusions from these studies would be consistent if assemblages under consideration are stable over time. The stability of butterfly assemblages in the Picos de Europa in northern Spain was examined at several levels of numerical resolution. The survey was carried out in 1993 and 1995, which allowed at least one complete turnover of all individuals in each locality. Butterfly assemblages were usually stable at the levels of number of species and total number of individuals, species presence and absence, and abundance rankings. But, absolute abundances of individual species changed from 1993 to 1995 out of synchrony with one another. Regional distributions and altitudinal ranges of species were also stable. Assemblages were similar in both study years, judging by similar site ordinations by reciprocal averaging. Overall, these results are in accordance with most studies where stability has been examined at several numerical levels; they also suggest that abundances of individual species do not vary enough to disrupt overall assemblage abundance rankings. Butterfly assemblages at sites at higher altitude tended to be more unstable in terms of abundance rankings and absolute abundances. This agrees with ecological theory predicting less stable assemblages in physically ‘harsh’ environments. We concluded that monitoring for a relatively short time period can give a clear picture of both local and regional butterfly biodiversity and species composition.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008885522377
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  • 61
    Digitale Medien
    Digitale Medien
    An evaluation of the gradsect biological survey method (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 1093-1121 
    Details
    ISSN: 1572-9710
    Schlagwort(e): gradsect survey ; biological surveys ; biodiversity ; land facets
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Biological surveys are necessary to gather species distribution data for the identification of priority conservation areas. The rationale of the gradsect method is that sampling (transects) oriented along the steepest environmental gradient should detect the maximum number of species in an area. The efficiency of the gradsect survey method was evaluated by comparing it to random, systematic and habitat-specific survey methods, during faunal field surveys (target groups: birds and dung beetles). Three gradsects were positioned within the study area to follow the major physiographical characteristics, incorporate all environmental strata (land facets) and yet be as logistically convenient as possible. The efficiency of survey methods was expressed as the number of species recorded per sampling unit effort and illustrated using bootstrap estimations to plot species accumulation curves. The gradsect method proved to be as efficient as the habitat-specific survey method and consiste ntly more efficient than the systematic and random surveys for both taxa sampled. The present study therefore illustrates that the gradsect survey method provides a cost-effective and swift representative sample of regional fauna. Moreover, the results indicate that land-form sequences, specifically ‘land facets’, are useful surrogates when sampling environmental diversity where distinct environmental gradients such as altitude and rainfall are absent.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008899802456
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  • 62
    Digitale Medien
    Digitale Medien
    The nature of biodiversity in hypogean waters and how it is endangered (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 1319-1338 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; endangerment ; hypogean waters ; stygobios
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The specialised aquatic hypogean, i.e. stygobiotic, fauna has been recognised in some regions moderately rich. Slovenia, the broader Dinaric region, and Europe are particularly rich with about 7–8% of all Metazoa and about 40% of Crustacea species being stygobionts. The hypogean biotic diversity is in general predominantly a crustacean diversity. The high number of stygobiont Crustacea–Malacostraca species can be explained by the near absence of Insecta as well as by their high endemicity and sometimes additional specialisation, i.e. the spatial and ecological partition of the environment by the species. Although one cave system may exceptionally shelter up to 40 stygobiont species, they are distributed there into separate associations. Among more than 2000 described stygobiontic Malacostraca species, which include close to 950 Amphipoda, the species numbers within some genera are very high (e.g. Niphargus with 275 spp.). With 10 orders represented the higher taxonomic diversity of stygobiont Malacostraca matches that of fresh waters or the sea. Comparison of some faunas shows that the limiting factors for biodiversity might be the lower ecological diversity of habitats and restricted food resources underground, both brought about to a high degree by the darkness and absence of plants. Being K-strategists, stygobionts are endangered by any sudden changes in their environment. In the case of an increased food input by modest organic pollution, they can be outcompeted by energetically demanding but competitively stronger recent immigrants from surface.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008916601121
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  • 63
    Digitale Medien
    Digitale Medien
    Effects of management works on the interstitial fauna of floodplain aquatic systems (River Rhône, France) (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 1179-1204 
    Details
    ISSN: 1572-9710
    Schlagwort(e): backwater ; biodiversity ; groundwater fauna ; management
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Long-term changes in composition, structure and biodiversity (i.e. taxonomic richness, diversity index, species traits and habitat-affinity) of interstitial assemblages were studied in two floodplain systems: a restored backwater and an artificial drainage canal. Before restoration, the backwater, affected by both terrestrialisation and eutrophication, was weakly populated by a low diversified fauna dominated by walkers, macrofauna, detritivores, and stygoxenes (i.e. taxa that occur incidentally in ground waters) that reproduce biparentally and lack parental care. This backwater displayed an upstream–downstream gradient in response to restoration works. Upstream, the dredging of fine organic sediments favoured inputs of nutrient-poor groundwater and exchanges between groundwater and surface water that induced an increase in taxonomic richness (in both herbivores and stygoxenes). Downstream the deposition of fine sediment that was suspended in the water column by restoration work enhanced colmation that induced a decrease in herbivore and swimming taxa, and an increase in mesofaunal taxa, whilst phreatobites (i.e. taxa specialized to interstitial life) remained absent from the system. The drainage canal that was artificially hollowed-out to lower the surrounding water table, harbors mixed assemblages of epigean (i.e. taxa of surface-water habitats) and hypogean (i.e. taxa of groundwater habitats) taxa. The upstream part, which is weakly influenced by surface waters, was colonized by phreatobites as oligotrophic conditions increased. The intermediate part, which is fed by surface water and where mesotrophic conditions occurred as habitats progressively matured and diversified, showed diversification of its fauna. The downstream part of the drainage canal displayed the reverse dynamic – this suggests a reduction in groundwater supply due to the clogging of sediment interstices fine sediments, the deposition of which is linked to the Rossillon backwater restoration works.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008843726483
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  • 64
    Digitale Medien
    Digitale Medien
    Global diversity of land planarians (Platyhelminthes, Tricladida, Terricola): a new indicator-taxon in biodiversity and conservation studies (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 1663-1681 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; conservation biology ; ecology ; hotspots ; indicator ; land planarians ; Terricola
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Biodiversity conservation requires prioritization of areas for in situ conservation. In that perspective, the present study documents the global diversity of a component of the soil macrofauna, the land planarians, and concerns an exploratory analysis of their possible role as indicators of biodiversity. Diversity is described by three quantitative methods: (1) hotspots of species richness, selecting areas richest in species, (2) hotspots of range-size rarity, identifying areas richest in narrowly endemic species, and (3) complementarity, prioritizing areas according to their greatest combined species richness. The biodiversity measures of species richness and range-size rarity show a great correspondence in the identification of hotspots of diversity; both measures identify the following seven areas as the most biodiverse for land planarians: Sao Paulo, Florianopolis, western Java, Tasmania, Sri Lanka, North Island/New Zealand, and Sydney. It is discussed to what extent the results for the land planarians correspond with those obtained in other studies that assessed biodiversity hotspots for taxa on a global scale. It is noteworthy that land planarians identify a few global hotspots of diversity that generally do not feature, or only have low rankings, in other studies: New Zealand, southeastern Australia, and Tasmania.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008994925673
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  • 65
    Digitale Medien
    Digitale Medien
    Notes on the soil ciliate biota (Protozoa, Ciliophora) from the Shimba Hills in Kenya (Africa): diversity and description of three new genera and ten new species (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 319-389 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; new species ; soil ciliates ; soil protozoa ; tropical Africa
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A very diverse ciliate community was found in nine soil samples from the Shimba Hills Nature Reserve in Kenya, equatorial Africa. The ciliates, respectively, their resting cysts, were re-activated from air-dried samples using the non-flooded Petri dish method. Species were determined from life and by silver impregnation. 34 (27%) of the 125 taxa identified had not yet been described in 1985, when the samples were collected and investigated. The richest samples, each containing 59 species, were those from a deciduous primary forest and a young secondary pine forest. The most remarkable species discovered in the Shimba Hills were Krassniggia auxiliaris, Bresslauides terricola, Gigantothrix herzogi, and Afrothrix darbyshirei. They are “flagships” with a very distinct morphology and easy to recognise due to their extraordinarily large body size. Krassniggia auxiliaris occurs also in Australia and probably has a restricted Gondwanan distribution, like some other ciliates. Bresslauides terricola was later found in soils from all main biogeographical regions, except for Antarctica. Gigantothrix herzogi and Afrothrix darbyshirei are still unique to the Shimba Hills. The following taxa are described in detail: Sikorops woronowiczae nov. gen., nov. spec., Arcuospathidium multinucleatum nov. spec., Dileptus similis Foissner, 1995, Plagiocampa bitricha nov. spec., Drepanomonas exigua exigua Penard, 1922, D. exigua bidentata nov. sspec., Parafurgasonia protectissima (Penard, 1922) nov. comb., P. terricola nov. spec., Brachyosoma brachypoda mucosa nov. sspec., Gigantothrix herzogi nov. gen., nov. spec., Afrothrix darbyshirei nov. gen., nov. spec., Oxytricha africana nov. spec., and O. elegans nov. spec.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008854912431
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  • 66
    Digitale Medien
    Digitale Medien
    Conservation regulation: a backward step for biodiversity? (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 679-707 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; environmental ethics ; European and UK conservation and wild animal welfare law ; hunting with hounds ; protected areas
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract An analysis, particularly from the UK and European Community perspectives, of the way in which the law dealing with the conservation of species and habitats has the potential effect, in some cases, of frustrating the comprehensive preservation of biological diversity. It is proposed that this state of affairs may have come about through the emphasis of one species to the detriment of others or through the failure to address comprehensive inter-species and habitat relationships. One of the propositions is that the application of protection to specific species, through conservation and wild animal welfare provisions, has been implemented in an arbitrary manner in the context of biodiversity preservation or in terms of an animal's level of sentiency or position on the phylogenetic scale. Another proposition is that the law has failed to protect and preserve the 'commonplace' in biodiversity and thus risks losing key components of ecosystems. Finally, the analysis examines the way in which traditional practices such as hunting with hounds may contribute to or frustrate biodiversity preservation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008892901324
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  • 67
    Digitale Medien
    Digitale Medien
    Whence useful plants? A direct relationship between biodiversity and useful plants among the Dusun of Mt. Kinabalu (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 797-818 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; conservation ; ethnobotany ; useful plants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Traditionally the Dusun indigenous people of Borneo consider Mt. Kinabalu the home of spirits and ancestors, and they are loath to climb the summit without good cause and plentiful propitiation. In apparent accordance with these beliefs, Projek Etnobotani Kinabalu has recorded few useful plants at high elevations on Mt. Kinabalu. We ask the question: is this an ecological relationship with fewer useful plants being collected at high elevations, or is it an ethnological product of belief with fewer plants collected where people fear to tread? With an indigenous Dusun plant expert (second author) well versed with all areas of Mt. Kinabalu, data on the number and kinds of useful plants were collected for dominant and indicator plant species (168 spp.) among all ecologically identified vegetation types. Results indicate that there are more useful plant species at lower elevations – but there are also more unused species. Once the data are corrected for change in the number of plant species with elevation (useful spp./total spp.), the proportion of useful species are not significantly different over elevation. Thus, useful species are a function of overall biodiversity (i.e., number of useful spp. are correlated with number of plant species, a secondary ecological factor) and not a direct ecological correlate with elevation. The number or kinds of uses also correlates with total number of plant species. In support of direct ecological causation, there is evidence that edaphic conditions (i.e., ultramafic and other poor soils) are associated with reduced proportions of useful species. Ultimately, both ethnological and ecological factors contribute to patterns of people's use of plants with many implications for conservation and biodiversity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008853413930
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  • 68
    Digitale Medien
    Digitale Medien
    Testing the use of specimen collection data and GIS in biodiversity exploration and conservation decision making in Guyana (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 727-751 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; biological collections ; GIS ; Guyana ; protected areas
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This paper presents the results of a study conducted at the request of the Government of Guyana by the Centre for the Study of Biological Diversity at the University of Guyana, and the Smithsonian Institution. The purpose of the study was to evaluate the utility of using systematic collections in identifying areas with a high priority for conservation. A biodiversity database and a gazetteer were assembled and interpreted primarily through the use of maps generated in ARC/INFO and ArcView. The data were examined to determine coverage and completeness, and while in general the results support a continued use of the methodology for making informed decisions in conservation related issues, several recommendations are offered in order to enhance the data. The primary use of the results of this study is in the identification of areas of interest for conservation and in the location of eleven areas covering most ecoregions in Guyana that are in need of additional study. The eleven areas have been chosen to avoid areas that are already allocated to logging and mining concessions or Amerindian lands. While it is true that this study would benefit from additional data and further analysis of those data, it is also true that decisions concerning areas for conservation in Guyana are being made in the near future, and if any data are to be used in this process, it will be those data presented in this paper.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008877222842
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  • 69
    Digitale Medien
    Digitale Medien
    Conservation and monographic research on the flora of Tropical America (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 1007-1015 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; conservation ; monograph ; Neotropics ; plant systematics ; tropics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Monographs provide fundamental data critical to making informed conservation decisions. Do modern monographs, however, contribute to our knowledge of the diversity of the Neotropical flora or has most of the enumeration of species already been accomplished in older monographs, floristic treatments, and other research? How well monographed is the Neotropical flora and what is the approximate number of Neotropical plant species new to science that await description? Authors of 76 recent monographs of the Neotropical flora recognized a total of 8711 species, of which 2487 (29%) were new species described by the author of the monograph during the course of the research. The number of species of flowering plants new to science remaining to be described is estimated to be ca. 22000, or about 25 percent of the total flora. These estimates show the critical importance of the contributions of monographers to an accurate and complete inventory of Neotropical plant diversity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008857429787
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  • 70
    Digitale Medien
    Digitale Medien
    Reversing borealization as a means to restore biodiversity in Central-European mountainforests – an example from the Krkonoše Mountains, Czech Republic (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 229-247 
    Details
    ISSN: 1572-9710
    Schlagwort(e): Norway spruce ; beech ; borealization ; biodiversity ; pioneer tree species ; succession ; forest restoration ; Black Triangle
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Forestry in the Central-European mountains is confronted with a severe forest decline, which is attributed to the combined effects of 'borealization', brought about by large scale continued spruce (mainly Picea abies) monocultures, and atmospheric deposition. Borealization is defined as enhanced soil acidification and litter accumulation, retarded nutrient cycling and changed forest climate in such planted coniferous forest ecosystems. An additional effect of borealization is a major decline in biodiversity of the stands. Based on a comparative study of Norway spruce and European beech stands in the Krkonoše National Park (Czech Republic), it is concluded that traditional management should be abandoned and that management should instead focus on regeneration towards broad-leaved or mixed forest stands, to enhance the stability of forest ecosystems and their biodiversity, and to reverse borealization in lower montane zones. Available surveys of forest typology were evaluated for their suitability in regeneration management and were found to be unsuitable, since they reflect the effects of borealization rather than true site conditions. The two main pioneer tree species, birch (Betula pendula) and mountain ash (Sorbus aucuparia), were found to improve soil conditions and reverse borealization. Furthermore, trends in natural vegetation and soil development in declined forests and clear-cuts, and their relevance for forest restoration management were studied, focusing on borealization and plant species diversity. It is concluded that this natural development offers very good possibilities for a more passive, low-cost restoration management.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008840603549
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  • 71
    Digitale Medien
    Digitale Medien
    Role of fungi in freshwater ecosystems (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 1187-1206 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; biogeography ; ecology ; freshwater ; fungi ; nutrient cycling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract There are more than 600 species of freshwater fungi with a greater number known from temperate, as compared to tropical, regions. Three main groups can be considered which include Ingoldian fungi, aquatic ascomycetes and non-Ingoldian hyphomycetes, chytrids and, oomycetes. The fungi occurring in lentic habitats mostly differ from those occurring in lotic habitats. Although there is no comprehensive work dealing with the biogeography of all groups of freshwater fungi, their distribution probably follows that of Ingoldian fungi, which are either cosmopolitan, restricted to pantemperate or pantropical regions, or in a few cases, have a restricted distribution. Freshwater fungi are thought to have evolved from terrestrial ancestors. Many species are clearly adapted to life in freshwater as their propagules have specialised aquatic dispersal abilities. Freshwater fungi are involved in the decay of wood and leafy material and also cause diseases of plants and animals. These areas are briefly reviewed. Gaps in our knowledge of freshwater fungi are discussed and areas in need of research are suggested.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008883716975
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  • 72
    Digitale Medien
    Digitale Medien
    Integrating biodiversity into decision making (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 7-16 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; decision making ; impact assessment ; institutions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The prominent theme in the debates concerning biodiversity has been the integration of biodiversity into social and economical processes. Integration has meant two different but related things: on one hand, biological phenomena have been contextualized in social and economical processes; on the other hand, biological issues have been incorporated into decision making. These two aspects of integration are related: knowing the context of biodiversity helps in assessing its worth for decision making. In what follows we will first look at the ramifications of decision making, on how to proceed when dealing with apparently incommensurable dimensions. Secondly, we will highlight some key issues in both biological and social impact assessment. Finally, we will propose a process model which takes into account the multiple aspects of biodiversity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008844721451
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  • 73
    Digitale Medien
    Digitale Medien
    Snake communities of moist rainforest and derived savanna sites of Nigeria: biodiversity patterns and conservation priorities (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 629-642 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; conservation ; rainforest ; snakes ; southern Nigeria ; savanna
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The taxonomic composition and the abundance of two communities of snakes were studied in two different areas of southern Nigeria. One community was studied in a derived savanna area (environs of Ejule, 06°54′N, 07°23′E), and one community was studied in a moist rainforest area (environs of Eket, 04°50′N, 07°59′E). Both the specific diversity and the mean frequency of observation of snakes were significantly higher in the forest area than in the savanna area, and the dominance index was higher in the savanna than in the forest site. However, most of the species were found in only one of the two areas, depending on their habitat requirements (e.g. Gastropyxis smaragdina, Dispholidus typus, Thelotornis kirtlandii, Dendroaspis jamesoni, Bitis nasicornis, Causus maculatus, etc). The forest community housed a significant number of arboreal and semiaquatic taxa, but in both sites most of the species were terrestrial. The commonest species in the forest area was an oviparous, semiaquatic, batracophagous natricine snake (Afronatrix anoscopus), whereas the commonest species in the savanna area was an oviparous terrestrial lacertophagous psammophine snake (Psammophis phillipsi). Some conservation implications of our biodiversity analyses are presented. It is suggested that the moist rainforest represents a critically endangered habitat, and should deserve special attention by the international scientific community. Oil industry activity is especially dangerous for snake communities, especially in the southernmost regions of Nigeria.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008849702810
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  • 74
    Digitale Medien
    Digitale Medien
    Effects of climate change on biodiversity: a review and identification of key research issues (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 1383-1397 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; climate change ; research issues
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Current knowledge of effects of climate change on biodiversity is briefly reviewed, and results are presented of a survey of biological research groups in the Netherlands, aimed at identifying key research issues in this field. In many areas of the world, biodiversity is being reduced by humankind through changes in land cover and use, pollution, invasions of exotic species and possibly climate change. Assessing the impact of climate change on biodiversity is difficult, because changes occur slowly and effects of climate change interact with other stress factors already imposed on the environment. Research issues identified by Dutch scientists can be grouped into: (i) spatial and temporal distributions of taxa; (ii) migration and dispersal potentials of taxa; (iii) genetic diversity and viability of (meta) populations of species; (iv) physiological tolerance of species; (v) disturbance of functional interactions between species; and (vi) ecosystem processes. Additional research should be done on direct effects of greenhouse gases, and on interactions between effects of climate change and habitat fragmentation. There are still many gaps in our knowledge of effects of climate change on biodiversity. An interdisciplinary research programme could possibly focus only on one or few of the identified research issues, and should generate input data for predictive models based on climate change scenarios.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008934324223
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  • 75
    Digitale Medien
    Digitale Medien
    Diversity of terrestrial isopod species along a transect through northern Israel (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 1469-1478 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; Isopoda ; Israel ; landscape types ; zoogeographical regions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The distribution of isopod species along a 70 km transect through northern Israel is described. The transect started from the Mediterranean seashore through Mt. Carmel and the Gilboa Mts. to the Jordan Valley. The habitats ranged from grassland, macqui to woodland in the Mediterranean region, onto grassland in the semi-arid region. Thirty isopod species were found, of these only one species was common to all the regions, and two species were found in four out of five regions. The largest number of species inhabited the mountainous habitats of Mt. Carmel and the Gilboa Mts: 20 and 14 species, respectively. Twelve species were found in the Coastal Plain; five of these were found exclusively there. Two of the four species found in the Jordan Valley were characteristic of that semi-arid region. Beta-diversity was found to be low in most cases and especially in the comparison between Mediterranean and semi-arid habitats.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008905729421
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  • 76
    Digitale Medien
    Digitale Medien
    Ecological risk assessment of transgenic plant releases: an Austrian perspective (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 1139-1158 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; cross-breeding partners ; genetically modified organisms ; regional aspects ; risk assessment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Some prerequisites for ecological risk assessment of transgenic plant releases are examined, with the aim of identifying research needs in Austria. Austria harbours high habitat diversity, extending from the Alps to the Pannonian continental lowlands. The Pannonian flora includes potential cross-breeding partners of several crops, which do not occur in western Europe. The border zones of major biogeographical regions contain high biodiversity, both in terms of species and habitat diversity; whether the genetic variability of widespread plant species is also increased in these areas requires further investigation. Especially in Alpine regions, transgenic grasses might eventually cause profound changes in community structure. Ecological risk assessment of transgenic crop releases should not only consider adverse effects on non-target species and ecosystems, but also their likely impact on the agroecosystems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008904525713
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  • 77
    Digitale Medien
    Digitale Medien
    Increase of biodiversity in homogeneous Scots pine stands by an ecologically diversified management (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 249-260 
    Details
    ISSN: 1572-9710
    Schlagwort(e): Scots pine ; biodiversity ; sustainable management
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Three important parameters of biodiversity in first generation Scots pine (Pinus sylvestris) forests on sandy soils have been evaluated: herbal layer diversity, natural regeneration and stand structure. The study took place in the Belgian Campine region, where the original oak–birch forest, degraded to heathlands in the course of time, were finally replaced by monocultures of Scots pine. These first generation pine forests are characterized by a low biodiversity. In maturing stands of this type, however, a spontaneous increase of biodiversity is noticed. Herbal species richness is very limited in all age classes. Different natural regeneration patterns are found. Referring to stand structure, the lengthening of the rotation favours the ingrowth of several hardwood species. As a consequence, the homogenous Scots pine stands are gradually and spontaneously transformed into heterogeneous mixed stands, featuring a noticeable increase in biodiversity. Selected human interventions may further increase biodiversity. The fundamental management principles are discussed: avoidance of major disturbances, lengthening of the rotation period, use of native tree species and natural regeneration, protection of microbiotopes and permanent monitoring.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008892620387
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  • 78
    Digitale Medien
    Digitale Medien
    Wildlife utilization and biodiversity conservation in Namibia: conflicting or complementaryobjectives? (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 549-559 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; wildlife ; Namibia ; valuation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This paper surveys different economic aspects of biodiversity conservation in Namibia's wildlife sector. One of the main causes of biodiversity loss has been the conversion of wildlife habitat to other land uses, notably livestock and crops. However, wildlife utilization strategies potentially yield significantly higher economic rates of return compared to these traditional land uses. Historically, the move towards land use patterns more favourable to wildlife has been hampered by a number of policy and institutional constraints. Since Namibia's independence, many of these constraints have now been removed or are in the process of reform. These moves are already encouraging investment in wildlife utilization, most notably in wildlife tourism and related activities. Some forms of wildlife utilization, particularly ecotourism and photographic safaris, will certainly complement the national and international commitment to biodiversity conservation. Consumptive uses may be economically attractive in some areas and will discourage further habitat conversion. However, uses which involve specialized management for the production of a few species may alter the species composition and functioning of ecosystems, causing conflict between the aims of wildlife utilization and biodiversity conservation. Less tangible components of biodiversity may remain under threat even under a well-designed wildlife utilization policy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008883813644
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  • 79
    Digitale Medien
    Digitale Medien
    Soil nematode biodiversity in terrestrial ecosystems (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 617-630 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; nematode ; species richness ; terrestrial ecosystems
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A review of the literature on nematode diversity (=number of species identified) of soil inhabiting nematodes was undertaken and analysed with regard to distance from the equator, vegetation type and sampling effort. After applying a correction factor for sampling effort the results indicated that species richness was greatest in temperate broadleaf forest (61.7 species per sample) followed by cultivated soil, grassland, tropical rainforest, temperate coniferous forests and polar vegetation. The maintenance of high biodiversity in cultivated soils is unexpected but may reflect the impact of dominance in calculating many indices. Species richness was greatest between latitudes 30–40° (93.9 species per sample) and least above 70°, the mean richness near the equator (i.e. 0–10°) was 80.6 species per sample. While these data would suggest that nematode diversity is not necessarily greatest at the equator, and evidence to support a 'humped back' theory of species richness is not conclusive, they contradict the suggestion that nematode diversity increases with increased latitude.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008852301349
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  • 80
    Digitale Medien
    Digitale Medien
    Biodiversity and the divide between culture and nature (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 165-181 
    Details
    ISSN: 1572-9710
    Schlagwort(e): atomistic vs. processual thinking ; biodiversity ; ecosocial analysis ; nature–culture dualism ; resilience
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The term biodiversity may help us to reach beyond the nature–culture dualism that has a debilitating effect on conservation thinking. This, however, depends on how the term is actually used. The opportunity is that the term connects dialectically together biological entities and their conditions of reproduction and may, consequently, facilitate a shift from atomistic to processual thinking in ecology and conservation. Analogously, the term offers resources for analyzing the dynamic dependence of human activities on natural processes. Health offers a fruitful metaphor for evaluating the resilience and conditions of reproduction of ecosocial systems. On the other hand, problems and contradictions in the application of the term arise from too schematic a perception of the relationship between scientific knowledge and human, social agency. Science influences human agency primarily on the long term, by helping to form new perspectives on what it means to lead a human life. Conservation concerns have a great influence on such perspectives. However, an emphasis on ‘crisis’ may be counterproductive: scientific arguments perform poorly in a crisis situation in which, instead, short-term interests of powerful social actors such as corporations, state agencies or professional groups may gain the upper hand.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008877628720
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  • 81
    Digitale Medien
    Digitale Medien
    Tree diversity and distribution in undisturbed and human-impacted sites of tropical wet evergreen forest in southern Western Ghats, India (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 1365-1381 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; conservation ; human interference ; species abundance ; tropical forest ; Western Ghats
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The composition, abundance, population structure and distribution patterns of all woody species (≥ 30 cm gbh) were investigated in an undisturbed and two adjacent human-impacted sites of a tropical wet evergreen forest in Kalakad National Park, Western Ghats, south India. Three 1-ha plots were established, one each in (i) an undisturbed site (named site UD), (ii) in a site selectively felled 35 years ago (site SF – small stems felled leaving the large trees (as shade) for developing it into a cardamom estate, on the failure of which the site was abandoned) and (iii) a frequently disturbed site (site FD – round woods logged for use in ovens for curing cardamom). These sites are 1 to 3 km apart in the same wet evergreen forest. In the three study plots a total of 2150 stems (mean density 716 ha−1) covering 122 species in 89 genera and 41 families were enumerated. Species richness was greatest (85 species ha−1) in the undisturbed site UD, intermediate (83) in SF and lowest (80) in FD. Tree density was greatest (855 stems ha−1) in site SF, intermediate (720) in UD and lowest (575) in FD. The forest stand was exceptionally voluminous in site UD (basal area 94.64 m2 ha−1), intermediate (66.9 m2) in SF and least (61.7 m2) in FD, due to tree removal for fuel in the latter sites. Species composition and abundance patterns markedly varied between the three sites. In UD and SF, primary forest species (Cryptocarya bourdillonii , Cullenia exarillata Myristica dactyloides etc.) occurred in greater density. In FD heliophilic secondary forest species (Elaeocarpus venustus, Litsea wightiana, Viburnum punctatum and Vitex altissima) were abundant, while these were absent in UD and SF. The species–area curve did not reach an asymptote in any of the sites on the 1-ha scale. The stand population structure was clearly reverse ‘J’ shaped in UD and SF, while small stems were 2- to 3-fold fewer in FD. Most trees exhibited clumped distribution of individuals on the 1-ha scale. Variation in the kind and richness of species and their abundance is related to human interference and the need for forest conservation is emphasized.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008949407385
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  • 82
    Digitale Medien
    Digitale Medien
    High plant diversity of lowland rainforest vestiges in eastern Madagascar (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 273-315 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; biogeography ; conservation biology ; dynamism ; ecology ; flora ; lowland rainforest ; Madagascar ; structure ; multivariate analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Based on cartography, floristic inventory and vegetation analysis in the north and south of the Eastern Domain of Madagascar we identified three original tropical rainforest types which are among the world's most biodiverse known sites for plants: the littoral forest on sand, the lowland forest on gneiss and the lowland forest on basalt. Floristic and structural comparisons were conducted on 37 plots of 50×10m. Multivariate analysis indicates that floristic composition is correlated with abiotic factors of rainfall, latitude, soil composition, and marine influence; the structure of the undergrowth is generally homogeneous and the canopy is more or less open. Many reserves must be created on gneiss, sand and basalt all along the eastern coast to preserve biodiversity from the deforestation process. On basalt, this is especially urgent because about only 10 000 ha of a very ancient forest that shelters numerous botanical novelties remain today.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008880718889
    Standort Signatur Erwartet Verfügbarkeit
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  • 83
    Digitale Medien
    Digitale Medien
    Functional diversity and community structure of micro-organisms in three arctic soils as determined by sole-carbon-source-utilization (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 205-221 
    Details
    ISSN: 1572-9710
    Schlagwort(e): Arctic ; biodiversity ; community ; micro-organisms ; soil
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Functional diversities of micro-organisms in arctic soils at three incubation temperatures were assessed using sole-carbon-source-utilization (SCSU). Soil samples were collected from an area of anthropogenic fertilization (mixed Dorset/Thule/Historic site), an area of animal enrichment (bird rock perches), and unaltered tundra (raised beach; control soil site). The micro-organisms were extracted from the soil samples and inoculated into Gram-negative (GN) Biolog plates incubated at 30°C, 10°C, and 4°C. Calculations of the Shannon index, substrate utilization richness, Shannon evenness, and the Jaccard coefficient of similarity were based upon substrate utilization on the Biolog plates. Principal component analysis distinguished microbial communities in enriched soils from unenriched soils. At 10°C and 4°C, Shannon indices of enriched soil microbial communities (10°C: soils influenced by wild animals=4.28, soils influenced by human activities=4.20; 4°C: soils influenced by wild animals=4.15, soils influenced by human activities=4.03) were significantly higher than unenriched soil microbial communities (10°C: 3.66; 4°C: 3.38). Substrate utilization richness and evenness displayed similar trends. Although Jaccard coefficients showed uniformity across the different soil samples, cluster analysis supported patterns demonstrated by PCA. Lower temperatures (4°C and 10°C) yielded greater resolution between soil microbial communities than 30°C based on Biolog colour development patterns.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008893826597
    Standort Signatur Erwartet Verfügbarkeit
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  • 84
    Digitale Medien
    Digitale Medien
    National biodiversity risk assessment: a composite multivariate and index approach (1998)
    Springer
    Biodiversity and conservation 7 (1998), S. 945-965 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; risk assessment ; national ; index ; multivariate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Due to the shortage of financial resources for international conservation assistance, the setting of priorities for this assistance is an important issue. A national biodiversity risk assessment index (NABRAI) is constructed to quantify national conservation performances and identify nation states of critical conservation concern. The index, which contains measures of biodiversity stock, flow and response measures, attempts to overcome several weaknesses present in other models used to prioritize nations for conservation assistance. Multivariate analyses of the index as well as economic and biodiversity resources reveal significant positive correlations between the NABRAI values and population density as well as land area exposed to high disturbance intensity. The combination of the multivariate analyses and the interpretation of NABRAI values allows for prioritization of biodiversity risk among the global community and can thus serve as an indicator of current priorities for policy makers. The present study also suggests two methods to incorporate a better understanding of biodiversity risk in models of conservation priorities; by including a wider range of variables and by developing a theoretical foundation for the relationship between the categories of variables used in the model.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008881405539
    Standort Signatur Erwartet Verfügbarkeit
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  • 85
    Digitale Medien
    Digitale Medien
    Functional significance of ungulate diversity in African savannas and the ecological implications of the spread of pastoralism (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 1643-1661 
    Details
    ISSN: 1572-9710
    Schlagwort(e): African savannas ; biodiversity ; conservation ; multispecies animal production
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The African savanna biome supports a higher diversity of ungulate species than is found in any other biome or continent. This exceptional faunal diversity and herbivore biomass density is directly linked to the high spatial heterogeneity of African savanna ecosystems. The dependence of herbivore dietary tolerance on body size translates into important size-related differences between savanna ungulate species in terms of habitat specificity, geographical range, and the share of community resources exploited. Intact savanna ungulate communities, with species distributed across body size classes and feeding guilds (grazer/browser), have strong regulatory influences on savanna ecosystem structure and function. Replacement with livestock systems of low diversity and high biomass density within a narrow body size range has occurred through the removal of competitors, pathogens, and predators, and the widespread provisioning of water. Overgrazing by livestock, coupled with episodic droughts, has caused widespread rangeland degradation and loss of floristic and faunal diversity which, by current models, is unlikely to recover to 'climax’ conditions even with destocking. In selected regions where potential still exists, African savanna biodiversity and human economic development will both be best served by the integration of sustainable wildlife utilization into multispecies animal production systems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008959721342
    Standort Signatur Erwartet Verfügbarkeit
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  • 86
    Digitale Medien
    Digitale Medien
    Exploring methods for rapid assessment of woody vegetation in the Batemi Valley, North-central Tanzania (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 447-470 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; ecological mapping ; vegetation classification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Conservation of local biological resources in remote areas requires efficient data and collection methods. This paper describes part of a local conservation initiative in Northern Tanzania in which an indigenous conservation group enlisted the support of outside scientists to explore means of preparing baseline ecological reports. Two factors are seen as important: one is local use of ecological resources and the other is local availability. This paper focuses on the second of these and considers woody species. A variety of ecological field methods, statistical analysis and remote sensing and mapping techniques are used to generate baseline ecological inventories. The fieldwork identified 101 woody species, representing 54 genera and 37 families in the Batemi area. There are three main vegetation types: Vangueria apiculata-Ficus sycomorus-Trichilia emetica type; Croton dictygamous-Euphorbia tirucalli-Grewia bicolor type; and Acacia tortilis-Balanites aegyptica-Euphorbia candelabrum type. The Landsat TM map identified four main land-cover classes: (1) bushland and woodland thicket, (2) woodland (3) wooded grassland, and (4) grassland with scattered trees, which includes agricultural areas and villages. The combination of these data and methods can be useful for conservation planning and long-term monitoring, but it is clear that ground-level local assessment is necessary to detect subtleties of human-environment interaction that are required for conservation planning.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008898331292
    Standort Signatur Erwartet Verfügbarkeit
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  • 87
    Digitale Medien
    Digitale Medien
    The impact of urban development on butterflies within a city region (1999)
    Springer
    Biodiversity and conservation 8 (1999), S. 1261-1279 
    Details
    ISSN: 1572-9710
    Schlagwort(e): biodiversity ; conurbations ; dispersal ; distributions ; habitat use ; lepidoptera ; metapopulations ; resource patches ; species' richness ; urban areas ; vagrants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effect of urban development on butterfly species' richness and species' incidence is tested for the Greater Manchester conurbation and two sample areas, mapped at finer scales, within the southern part of the conurbation. The tests include measures of bias for recording effort (number of visits). Species' richness is found to increase with percentage urban cover for Greater Manchester (tetrad scale) and decrease with urban cover for the two sample areas in South West Manchester (1 km scale) and the Mersey Valley (100 m scale). For Greater Manchester, the increase in species' richness with increased urban cover is largely explained by lower species' richness at higher altitude in the Pennines bounding the conurbation. For the two sample areas, decreasing species' richness associated with increasing urban cover corresponds with reductions in the areas of a number of semi-natural habitats, hostplants and nectar sources. Despite these statistically significant correlations, the impact of urban cover on species' richness is weak. The maximum loss rate identified anywhere within the region is 0.81 species per 10% change in urban cover for South West Manchester. This finding may reflect on the generally low species diversity of the region. However, these results could be influenced by recording and sampling artefacts, particularly the failure of mapping programmes to distinguish vagrant individuals from breeding populations and a bias of records to vagrants. This is supported by the higher correlations between species' incidence and nectar sources than between species' incidence and their hostplants. Adult butterflies are opportunistic nectar users and nectar sources are more widely spread and thus less influenced by urban development than are specific butterfly hostplants. The finding may also reflect on the capacity of most of the butterfly species to breed successfully on tiny areas of hostplant existing within extensively built-up areas. Moreover, the capacity of butterfly species to persist by using small fragments of hostplants would be enhanced by vagrancy. If this is indeed the case, it is a finding that would support the value of small patches in butterfly metapopulations, albeit ones comprising incomplete complements of resources required during the life cycle. The incidence of most species decreases with increase in urban cover. Multivariate analyses indicate that this is owing to corresponding declines in hostplant-habitats and nectar sources. Five species increase with urban cover, but none attain formal significance. Associations among hostplants and habitat variables in a principal components analysis suggest that, in three cases (Pieris brassicae, P. rapae, Celastrina argiolus), this is owing to increasing areas of their hostplants within urban environments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008984905413
    Standort Signatur Erwartet Verfügbarkeit
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