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  • Articles  (162)
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  • Books  (3)
  • Articles  (162)
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  • 1
    Publication Date: 2022-05-27
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Aguado, M. T., Ponz-Segrelles, G., Glasby, C. J., Ribeiro, R. P., Nakamura, M., Oguchi, K., Omori, A., Kohtsuka, H., Fisher, C., Ise, Y., Jimi, N., & Miura, T. Ramisyllis kingghidorahi n. Sp., a new branching annelid from Japan. Organisms Diversity & Evolution. (2022), https://doi.org/10.1007/s13127-021-00538-4.
    Description: Among over 20,000 species of Annelida, only two branching species with a highly modified body-pattern are known until now: the Syllidae Syllis ramosa McIntosh, 1879, and Ramisyllis multicaudata Glasby et al. (Zoological Journal of the Linnean Society, 164, 481–497, 2012). Both have unusual ramified bodies with one head and multiple branches and live inside the canals of host sponges. Using an integrative approach (combining morphology, internal anatomy, ecology, phylogeny, genetic divergence, and the complete mitochondrial genome), we describe a new branching species from Japan, Ramisyllis kingghidorahi n. sp., inhabiting an undescribed species of Petrosia (Porifera: Demospongiae) from shallow waters. We compare the new species with its closest relative, R. multicaudata; emend the diagnosis of Ramisyllis; and discuss previous reports of S. ramosa. This study suggests a much higher diversity of branching syllids than currently known. Finally, we discuss possible explanations for the feeding behaviour in the new species in relation to its highly ciliated wall of the digestive tubes (especially at the distal branches and anus), and provide a hypothesis for the evolution of branching body patterns as the result of an adaptation to the host sponge labyrinthic canal system.
    Description: Open Access funding enabled and organized by Projekt DEAL. This study was financed by the Biodiversitätsmuseum (PI:MTA), Georg August University, Göttingen, and by Grant-in Aid for Scientific Research A (No. 18H04006) (PI:TM) from the Ministry of Education, Culture, Sports, Science and Technology of Japan. GP-S was supported by the “Contratos Predoctorales para la Formación de Doctores 2016” program of MINECO, Spain (code: BES-2016–076419), co-financed by the European Social Found. RPR was supported by the program “Contratos predoctorales para Formación de Personal Investigador, FPI-UAM,” Universidad Autónoma de Madrid.
    Keywords: Mitochondrial genome ; Phylogenetics ; Sponge ; Syllidae ; Symbiosis ; Morphology ; Anatomy ; Ecology
    Repository Name: Woods Hole Open Access Server
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  • 2
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    Springer Nature | Springer
    Publication Date: 2024-04-05
    Description: This open access book describes the serious threat of invasive species to native ecosystems. Invasive species have caused and will continue to cause enormous ecological and economic damage with ever increasing world trade. This multi-disciplinary book, written by over 100 national experts, presents the latest research on a wide range of natural science and social science fields that explore the ecology, impacts, and practical tools for management of invasive species. It covers species of all taxonomic groups from insects and pathogens, to plants, vertebrates, and aquatic organisms that impact a diversity of habitats in forests, rangelands and grasslands of the United States. It is well-illustrated, provides summaries of the most important invasive species and issues impacting all regions of the country, and includes a comprehensive primary reference list for each topic. This scientific synthesis provides the cultural, economic, scientific and social context for addressing environmental challenges posed by invasive species and will be a valuable resource for scholars, policy makers, natural resource managers and practitioners.
    Keywords: Ecosystems ; Environment, general ; Terrestial Ecology ; Landscape Ecology ; Ecology ; Environmental Sciences ; Freshwater and Marine Ecology ; Invasive species in the United States ; USDA Forest Service Technical Report ; Terrestial and aquatic systems ; Invasive species science ; Invasive pests, climate and social sciences ; Forest and rangeland management in the United States ; Open Access ; Ecological science, the Biosphere ; The environment ; Botany & plant sciences ; thema EDItEUR::P Mathematics and Science::PS Biology, life sciences::PSA Life sciences: general issues::PSAF Ecological science, the Biosphere ; thema EDItEUR::R Earth Sciences, Geography, Environment, Planning::RN The environment ; thema EDItEUR::P Mathematics and Science::PS Biology, life sciences::PST Botany and plant sciences
    Language: English
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  • 3
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    Springer Nature | Springer
    Publication Date: 2024-04-05
    Description: This open access book presents and analyzes the results of more than 30 years of long-term ecological research in riparian forest ecosystems with the aim of casting light on changes in the dynamics of riparian forests over time. The research, focusing on the Ooyamazawa riparian forest, one of the remaining old-growth forests in Japan, has yielded a number of interesting outcomes. First, it shows that large-scale disturbances afford various trees opportunities for regeneration and are thus the driving force for the coexistence of canopy trees in riparian forests. Second, it identifies changes in reproductive patterns, highlighting that seed production has in fact quantitatively increased over the past two decades. Third, it describes the decline in forest floor vegetation caused by deer grazing and reveals how this decline has affected bird and insect populations. The book illustrates the interconnectedness of phenomena within an ecosystem and the resultant potential for cascade effects and also stresses the need for long-term ecological studies of climate change impacts on forests. It will be of interest to both professionals and academics in the field of forest science.
    Keywords: Ecology ; Forestry ; Plant Ecology ; Ecosystems ; Environment, general ; Riparian Ecology ; Environmental Sciences ; Changes in forest vegetation ; Long-term ecological research ; Life history of trees ; Riparian forest ; Natural disturbance ; Masting behavior ; Forest decline ; Ecological science, the Biosphere ; Forestry & silviculture: practice & techniques ; Botany & plant sciences ; The environment ; thema EDItEUR::P Mathematics and Science::PS Biology, life sciences::PSA Life sciences: general issues::PSAF Ecological science, the Biosphere ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TV Agriculture and farming::TVR Forestry and silviculture ; thema EDItEUR::P Mathematics and Science::PS Biology, life sciences::PST Botany and plant sciences ; thema EDItEUR::R Earth Sciences, Geography, Environment, Planning::RN The environment
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  • 4
    Keywords: Biomass conversion ; Biotechnology ; Chemical Engineering ; Chemistry industry ; Industrial Chemistry ; Kent ; Riegel ; biochemical engineering
    Description / Table of Contents: Substantially revising and updating the classic reference in the field, this handbook offers a valuable overview and myriad details on current chemical processes, products, and practices. No other source offers as much data on the chemistry, engineering, economics, and infrastructure of the industry. The Handbook serves a spectrum of individuals, from those who are directly involved in the chemical industry to others in related industries and activities. It provides not only the underlying science and technology for important industry sectors, but also broad coverage of critical supporting topics. Industrial processes and products can be much enhanced through observing the tenets and applying the methodologies found in chapters on Green Engineering and Chemistry (specifically, biomass conversion), Practical Catalysis, and Environmental Measurements; as well as expanded treatment of Safety, chemistry plant security, and Emergency Preparedness. Understanding these factors allows them to be part of the total process and helps achieve optimum results in, for example, process development, review, and modification. Important topics in the energy field, namely nuclear, coal, natural gas, and petroleum, are covered in individual chapters. Other new chapters include energy conversion, energy storage, emerging nanoscience and technology. Updated sections include more material on biomass conversion, as well as three chapters covering biotechnology topics, namely, Industrial Biotechnology, Industrial Enzymes, and Industrial Production of Therapeutic Proteins.
    Pages: Online-Ressource (XIV, 1562 pages)
    ISBN: 9780387278438
    Language: English
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  • 5
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    Agriculture and human values 17 (2000), S. 125-139 
    ISSN: 1572-8366
    Keywords: Environment ; Fisheries ; Fordism ; Nation-State ; Regulation ; Supranational State ; Transnational corporations ; Transnational State
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This analysis uses an analytical frameworkgrounded in political economy perspectives of theglobalization of the agro-food sector combined with acase study approach focusing on the Marine StewardshipCouncil (MSC) to inform discussions regarding thecharacteristics of societal regulation in thepost-Fordist era. More specifically, this analysisuses the case of the emergence of the MSC toinvestigate propositions regarding the existence of,and location of, nascent forms of a transnationalState. The MSC proposes to regulate the certificationof sustainable fisheries at the global level throughan eco-labeling program. The MSC was created in 1996by the transnational environmental organization theWorld Wildlife Fund and the transnational corporationUnilever. The emergence of the MSC has generatedheated discussion in fisheries management circles thatis in general divided along North/South lines. Thisanalysis indicates that the case of the MSC providesvaluable insights into the possible characteristics ofsupranational regulatory mechanisms that might emulatethe role of the nation-State in the post-Fordist era.
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  • 6
    ISSN: 1573-5117
    Keywords: Ecology ; macrophytes ; mesotrophic lake ; planktonic ciliates ; Protozoa ; shallow lake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The species richness and seasonal development of planktonic ciliates were studied and compared in two shallow mesotrophic lakes, one covered with dense submerged macrophytes, the other macrophyte poor. Considerable differences in ciliate species composition, dominant taxa, abundance and biomass were observed. Ciliates were much more species rich in the macrophyte-rich lake, while they were more abundant numerically in the macrophyte-poor lake. Altogether, 96 species, included in 53 genera, 14 orders were identified. Among them, 80 species (included in 45 genera, 14 orders) observed from the macrophyte-rich lake, against 49 species (36 genera, 12 orders) were from the macrophyte-poor lake. In the macrophyte-rich lake, the mean abundance and biomass were 13.5 cells ml-1 and 547.10 μg l-1 f.w.; abundance and biomass were higher in spring and winter; naked oligotrichs dominated total ciliate abundance and Peritrichida dominated the biomass. In the macrophyte-poor lake, ciliate mean abundance and biomass were 35.5 cells ml-1 and 953.39 μg l-1 f.w.; abundances peaked in autumn; Scuticociliates dominated the abundance and Tintinnids dominated the biomass. Possible causes for the observed differences are discussed.
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  • 7
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    Environment, development and sustainability 2 (2000), S. 277-304 
    ISSN: 1573-2975
    Keywords: Systems of Knowledge ; Local Knowledge ; Fisheries ; Resource Management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Sociology
    Notes: Abstract During the last 20 years, the existence of rich systems of local knowledge, and their vital support to resource use and management regimes, has been demonstrated in a wide range of biological, physical and geographical domains, such as agriculture, animal husbandry, forestry and agroforestry, medicine, and marine science and fisheries. Local knowledge includes empirical and practical components that are fundamental to sustainable resource management. Among coastal-marine fishers, for example, regular catches and, often, long-term resource sustainment are ensured through the application of knowledge that encompasses empirical information on fish behaviour, marine physical environments, fish habitats and the interactions among ecosystem components, as well as complex fish taxonomies. Local knowledge is therefore an important cultural resource that guides and sustains the operation of customary management systems. The sets of rules that compose a fisheries management system derive directly from local concepts and knowledge of the resources on which the fishery is based. Beyond the practical and the empirical, it is essential to recognise the fundamental socio-cultural importance of local knowledge to any society. It is through knowledge transmission and socialisation that worldviews are constructed, social institutions perpetuated, customary practices established, and social roles defined. In this manner, local knowledge and its transmission, shape society and culture, and culture and society shape knowledge. Local knowledge is of great potential practical value. It can provide an important information base for local resources management, especially in the tropics, where conventionally-used data are usually scarce to non-existent, as well as providing a shortcut to pinpoint essential scientific research needs. To be useful for resources management, however, it must be systematically collected and scientifically verified, before being blended with complementary information derived from Western-based sciences. But local knowledge should not be looked on with only a short-term utilitarian eye. Arguments widely accepted for conserving biodiversity, for example, are also applicable to the intellectual cultural diversity encompassed in local knowledge systems: they should be conserved because their utility may only be revealed at some later date or owing to their intrinsic value as part of the world's global heritage. At least in cultures with a Western liberal tradition, more than lip-service is now being paid to alternative systems of knowledge. The denigration of alternative knowledge systems as backward, inefficient, inferior, and founded on myth and ignorance has recently begun to change. Many such practices are a logical, sophisticated and often still-evolving adaptation to risk, based on generations of empirical experience and arranged according to principles, philosophies and institutions that are radically different from those prevailing in Western scientific circles, and hence all-but incomprehensible to them. But steadfastly held prejudices remain powerful. In this presentation I describe the 'design principles' of local knowledge systems, with particular reference to coastal-marine fishing communities, and their social and practical usefulness. I then examine the economic, ideological and institutional factors that combine to perpetuate the marginalisation and neglect of local knowledge, and discuss some of the requirements for applying local knowledge in modern management.
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  • 8
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    Agriculture and human values 16 (1999), S. 161-167 
    ISSN: 1572-8366
    Keywords: Biotechnology ; Culture ; Dependency ; Ecology ; Food systems ; Organism ; Restructuring ; Seeds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract It is important to talk about corporations as a class, about trade agreements, and about government policy; but without examining specific examples of how real corporations actually shape the world to suit their purposes, we stand little chance of understanding the determinative forces behind government policy and trade agreements, and even less chance of affecting them. This article uses the metaphor of “genetics” (inherent character) to examine two major transnational corporations operating at the extremes of restructuring life.
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  • 9
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    AI & society 12 (1998), S. 21-28 
    ISSN: 1435-5655
    Keywords: Ecology ; Organisational design ; Production ; Quality of work
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Produktion 2000 is a German federal framework programme which supports the development of technology, organisation and qualification for production in industry. The Programme was launched in 1995 in view of the urgent need for improvement felt by industry itself after a very careful analysis and definition phase. The Programme is managed by a special Agency on behalf of the Federal Ministry. Their staff offers support in defining, implementing, running and controlling collaborative industry-driven projects and by awarding financial grants to the project partners. Strategic projects and first results are reported.
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  • 10
    ISSN: 1432-1890
    Keywords: Key words Ectomycorrhizas ; Abies alba ; Characterization ; Ecology ; Confocal microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Naturally occurring ectomycorrhizas of silver fir (Abies alba Miller) were studied in two stands, one natural and one artificial, situated in Central Italy. A total of 25 mycorrhizal types was classified, for eight of which the mycobiont was identified at the species level. Analysis of macroscopic and microscopic features and matching of field-collected carpophores with associated mycorrhizas led to the tentative identification of several other types encountered during this study, at least at the genus level. No significant differences were noticed between natural and artificial stands in the relative richness of mycorrhizal types found on A. alba, indicating the maturity of the artificial stand with regard to succession of ectomycorrhizal fungi. Confocal laser scanning microscopy was used for visualization of mycorrhizal structures formed by Lactarius spp., without the need for specific staining with a fluorochrome, thanks to latex autofluorescence. This technique allowed observation of several structures in greater detail than with conventional light microscopy.
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  • 11
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    Plant ecology 138 (1998), S. 89-96 
    ISSN: 1573-5052
    Keywords: Ecology ; Functional groups ; Diversity ; Herbivory ; Heterogeneity ; Patch dynamics ; Pattern ; Plant-animal interaction ; Rangelands ; Redundancy ; Scale ; Shifting mosaic ; Succession
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Grassland patches within a semi-arid savanna were evaluated over 45-years for (1) local temporal dynamics of basal area for five dominant grass species within long-term heavily grazed and ungrazed treatments, (2) the influence of soil depth (resource availability) on vegetation dynamics, and (3) the applicability of community-level grazing response groups over fine-scale patterns of soil heterogeneity. Temporal patterns in species composition and basal area were dependent upon soil depth. In the heavy grazed treatment, Hilaria belangeri dominated deep soils while Erioneuron pilosum and Bouteloua trifida were restricted to shallow soils. In the ungrazed treatment, removal of grazing resulted in successional changes that were significantly different across soil depths. After 45 years without grazing, Eriochloa sericea was most abundant on deep soils while Bouteloua curtipendula was more abundant on intermediate and shallow soils. Community-level functional groups that are based on grazing were not appropriate when multiple pattern-driving variables were considered across multiple scales indicating that functional groups should only be applied to certain processes at specific scales. Within the ungrazed treatments, variable soil depths have resulted in a shifting mosaic in time and space where early- and late-successional species co-exist continuously but spatially separated within the community. In the heavily grazed treatment, species are somewhat spatially arranged by soil depths, but much of the inherent heterogeneity is eliminated and species composition is dominated by the three grazing-resistant short-grasses. Broad scale successional changes may appear linear and predictable while at finer scales, the same changes may be described as non-linear and dependent upon soil depth resulting in thresholds that are partially explained by weather patterns, seed bank limitations and competitive inhibitions.
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  • 12
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    Artificial life and robotics 1 (1997), S. 21-26 
    ISSN: 1614-7456
    Keywords: Evolution ; Software ; Artificial life ; Natural selection ; Artificial selection ; Evolvability ; Ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract A review of efforts to implement the process of evolution in a computational medium. The review will cover prominent examples, and discuss the major classes of implementations, their successes, and the obstacles they face.
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  • 13
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    Plant ecology 130 (1997), S. 101-109 
    ISSN: 1573-5052
    Keywords: Distribution ; Ecology ; Morphology ; Nothofagus ; South American
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The morphology of the 11 taxa of South American Nothofagus are compared. Thirty eight characteristics were taken into account: 12 from leaves, 3 from stipules, 3 from buds, 6 from cupules, 7 from fruits, 4 from petioles and 3 from male flowers. The data matrix, with average values of 100 measurements per taxon, was analyzed with multivariate statistical methods of classification and polar and spatial ordination. Five groups were established: The first one (Nothofagus obliqua, N. obliqua var. macrocarpa, N. leoni and N. alessandrii), with deciduous leaves, is adapted to mediterranean climatic conditions. The second groups (N. dombeyi, N. nitida and N. antarctica), with small leaves which are evergreen for the first two species and deciduous for the last, develops under temperate humid conditions typical of the Valdivian region. The three remaining groups correspond to isolated species with different requirements: N. glauca, has large deciduous leaves and colonizes the most xerophytic biotope that a Nothofagus in central Chile can tolerate. N. pumilio, with mid-sized deciduous leaves, is adapted to the cold and dry zones of the southern Andes. Finally, N. betuloides, with small evergreen leaves, grows in the cold/humid somewhat boggy conditions of the Magellanic region.
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  • 14
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    Mycorrhiza 6 (1996), S. 215-225 
    ISSN: 1432-1890
    Keywords: Key words Mycorrhiza ; Ericales ; Hosts ; Specificity ; Ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Ericoid mycorrhiza, found in plants belonging to a few families of the Ericales, is seen as the most specific of mycorrhizas, and this has generated much research into the basis of the specificity. Recently, however, non-vascular plants have been found to be able to form the same type of mycorrhiza, and the diversity of the fungal partners has expanded. This review assesses the present state of host and ecological specificity of ericoid mycorrhizas and discusses future lines of research.
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  • 15
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    Oecologia 108 (1996), S. 552-561 
    ISSN: 1432-1939
    Keywords: Drosophila ; Colonization ; Ecology ; Succession ; Guild
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The guild of “cosmopolitan” Drosophila coexist almost worldwide and yet the mechanisms that underlie this coexistence are unknown. The larval resource of the guild is decaying fruit and vegetables, but the species show little specialization and can coexist on a single resource, such as oranges. In southern California the guild includes D. simulans (SIM), D. melanogaster (MEL), D. pseudoobscura (OBS), D. immigrans (IMM), D. hydei (HYD) and D. busckii (BUS). These species show consistent differences in their colonization of decaying organges, differences that may promote their coexistence. This study tested whether the colonization pattern of a species is determined primarily by attraction to specific resource types (decayed or fresh organges), by ability to colonize new resource patches, or by dependence on a successional sequence of Drosophila species. The experiments compared oranges that were pre-aged prior to a colonization period and showed that the colonization pattern of each species (except OBS) was driven primarily by its decay-dependent attraction to oranges. While OBS exhibited a pattern of colonization independent of pre-aging, the remaining species all showed some preference for older (7-day pre-aged) over fresh oranges. Their overall pattern of attraction, ordered by high relative abundance on fresher organges, was SIM〉MEL=IMM〉HYD=BUS. BUS, a specialist on decaying plant material, was the only species that showed a preference for 11-day over 7-day oranges. Pre-aging the oranges under covers, to prevent prior colonization by Drosophila, did not change the interspecific pattern of colonization, indicating that microbial decay was driving the changes in attraction. The patterns of attraction separated two ecologically similar pairs (SIM from MEL; IMM from HYD) and published data on ethanol tolerance show that, in each pair, the earliest colonizer has the lower tolerance. This suggests an important interplay between colonization patterns and physiological optima.
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    Oecologia 105 (1996), S. 329-335 
    ISSN: 1432-1939
    Keywords: Carnivora ; Ecology ; Population density ; Scale ; Spatial pattern
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A large part of ecological theory has been developed with the assumption that intra- and inter-specific patterns of density and spatial distribution can be consistently and reliably compared, and that these patterns have represented populations across nonstudied landscapes. These assumptions are erroneous. We found that log10 population density estimates consistently decreased linearly with log10 spatial extent of study areas for species of terrestrial Carnivora. The size of the study area accounted for most of the variation in population estimates, and study areas increased with the female body mass of the study species. But study sites consistently had higher densities than can be expected for nonstudy sites, regardless of the size of the study area, because study sites are typically chosen based on a priori knowledge of high density. Inter-specific comparisons of density and distribution might provide more insight into community organization after intra-specific density estimates have been scaled by the study areas, and related to the nonstudied landscapes within each species' geographic range.
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    Oecologia 107 (1996), S. 588-594 
    ISSN: 1432-1939
    Keywords: Allometry ; Carnivora ; Density ; Ecology ; Scale
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A regression slope of −0.75 between log10 density and log10 body mass is thought to express equivalence of energy conversion among species' populations of similar taxonomic and trophic status. Using larger sample sizes than the usual 1–3 density estimates per species, we estimated a regression slope of −0.71 for terrestrial mammalian carnivores. We investigated the sampling variation in this estimate, and those derived from smaller intra-specific subsets, using 1000-iteration bootstrap analyses to obtain 90% confidence intervals. As expected, these widened as random subsets were reduced in size, but always contained the postulated −0.75. However, log10 density also declined as 3/4 of the log10 spatial extent of study area, and study area accounted for virtually all of the variation in density that was previously thought due to body mass. We removed the effect of study area by using the species-specific regression models between density and study area to predict density at a common scale of 400 km2. These common-scale densities regressed against body mass with a slope of −0.16, but separated into body mass classes less than and greater than 11 kg, they produced slopes that were not significantly different from zero. We show that the allometry of density could be a case of circular logic, whereby body mass has influenced the investigator's choice of study area, and the resulting scale-dependent densities are related back to body mass. To test the allometry hypothesis, the effect of study area on density estimates needs to be removed. This requires conducting larger-scale studies of the smaller-bodied species so that all species compared are represented by an average study area that is near the common scale. Furthermore, study sites need to be selected and designed to represent more than the local detail in species' density.
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    Environmental management 20 (1996), S. 831-840 
    ISSN: 1432-1009
    Keywords: Adaptive management ; Biodiversity ; Hydropower ; Glen Canyon Dam ; Ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Adaptive management is a policy framework within which an iterative process of decision making is followed based on the observed responses to and effectiveness of previous decisions. The use of adaptive management allows science-based research and monitoring of natural resource and ecological community responses, in conjunction with societal values and goals, to guide decisions concerning man's activities. The adaptive management process has been proposed for application to hydropower operations at Glen Canyon Dam on the Colorado River, a situation that requires complex balancing of natural resources requirements and competing human uses. This example is representative of the general increase in public interest in the operation of hydropower facilities and possible effects on downstream natural resources and of the growing conflicts between uses and users of river-based resources. This paper describes the adaptive management process, using the Glen Canyon Dam example, and discusses ways to make the process work effectively in managing downstream natural resources and biodiversity.
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    Environmental management 20 (1996), S. 523-539 
    ISSN: 1432-1009
    Keywords: Water control ; Floodplain ; Fisheries ; Bangladesh ; Chandpur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Bangladesh is a very flat delta built up by the Ganges—Brahmaputra—Meghna/Barak river systems. Because of its geographical location, floods cause huge destruction of lives and properties almost every year. Water control programs have been undertaken to enhance development through mitigating the threat of disasters. This structural approach to flood hazard has severely affected floodplain fisheries that supply the major share of protein to rural Bangladesh, as exemplified by the Chandpur Irrigation Project. Although the regulated environment of the Chandpur project has become favorable for closed-water cultured fish farming, the natural open-water fishery loss has been substantial. Results from research show that fish yields were better under preproject conditions. Under project conditions per capita fish consumption has dropped significantly, and the price of fish has risen beyond the means of the poor people, so that fish protein in the diet of poor people is gradually declining. Bangladesh is planning to expand water control facilities to the remaining flood-prone areas in the next 15–20 years. This will cause further loss of floodplain fisheries. If prices for closed-water fish remain beyond the buying power of the poor, alternative sources of cheap protein will be required.
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    Plant systematics and evolution 203 (1996), S. 181-281 
    ISSN: 1615-6110
    Keywords: Poaceae ; Aveneae ; Helictotrichon ; Avenula ; Ecology ; biogeography ; chromosome numbers ; polyploidy ; Mediterranean Region
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The geographical distribution of the grass genusHelictotrichon in the Mediterranean Region is analysed and mapped for 33 taxa. Based on only a single life form (perennial herb), a variety of edaphically, climatically and altitudinally differently adapted species complexes has evolved in the area. Most of these complexes show west-east disjunctions and contain geographically, sometimes even edaphically vicarious taxa with complementary distribution. A transition from mesomorphic to xeromorphic habit occurred independently in different species groups and led to the establishment of the “modern” Mediterranean taxa which are in part highly polyploid derivatives of more mesophilic diploids. The significance of polyploidy, patterns of parapatric and sympatric distribution, biogeographical borders, and centres of species diversity are discussed in context with the history of the Mediterranean vegetation. New combinations are:Helictotrichon setaceum subsp.petzense, H. pratense subsp.lusitanicum, H. praetutianum.
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    Environmental biology of fishes 45 (1996), S. 219-235 
    ISSN: 1573-5133
    Keywords: Ecology ; Behaviour ; Evolution ; Cichlids ; Fisheries ; Conservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Ecological conditions in tropical lacustrine systems are considered by focusing on the evolution, maintenance, exploitation and vulnerability of fish communities in the African Great Lakes. The exceptionally high biodiversities in the littoral/sublittoral zones of the very ancient, deep, clear, permanently stratified rift lakes Tanganyika and Malawi, are contrasted with the simpler systems in their pelagic zones, also with biodiversity in the much younger, shallower Victoria, the world's largest tropical lake.
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  • 22
    ISSN: 1573-5133
    Keywords: Estuaries ; Ecology ; Hermaphroditism ; Diet ; Age ; Growth ; Distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Sharp declines in catches prompted a detailed study of the commercially and culturally important ‘terubok’ Tenualosa toli, which lives in the fast-flowing, turbid estuaries and adjacent shallow coastal waters of Sarawak. Its reproduction, diet, age and growth were investigated. An absence of small females and large males, together with histological data showing transitional gonads, suggest that T. toli is a protandrous hermaphrodite. Ageing based on otoliths indicates that individuals may not live more than about two years. Male fish spawn towards the end of their first year, change sex (transitional gonads were recorded in fish from 14 to 31 cm SL) and spawn as females in their second year. Spawning takes place in the middle reaches of estuaries and females deposit all their eggs at once. Fecundity is linearly related to fish length but shows significant seasonal and site variations. Hermaphroditism is discussed in relation to possible environmental and isolating mechanisms. T. toli is a zooplanktivore eating mainly calanoid copepods. Laser-ablation inductively-coupled plasma mass spectroscopy of trace elements across otoliths revealed that the species does not move into full seawater or freshwater, but completes its life cycle in estuarine and adjacent coastal waters. Therefore T. toli populations in each estuary and adjacent coastal waters may be relatively isolated from one another, and hence particularly susceptible to overfishing.
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  • 23
    ISSN: 1573-0832
    Keywords: C. neoformans ; Ecology ; Epidemiology ; Fungus isolation
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    Topics: Biology , Medicine
    Notes: Abstract The presence ofCryptococcus neoformans in various natural sources, such as bird droppings, fruits and vegetables, was investigated. A total of 711 samples were analyzed;C. neoformans var.neoformans was isolated from seven out of 74 bird droppings (9.5%), with parrots as one of the most significant sources. Fruits were positive in 9.5% of the 169 samples studied, specially citrus fruits, particularly grapefruit, in which the highest frequency was found. From the 468 vegetable samples, only 20 were positive (4.2%). It is emphasized that five of the positive vegetables species are autochthonous to Mexico: avocado (Nectandra salicifolia), beet (Beta vulgaris var.quinopodiace), chayote (Sechium edule), stringbean (Cassia sp), and nopal (Opuntia ficus-indica).
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  • 24
    ISSN: 1432-1009
    Keywords: Reservoir ; Fisheries ; Breeding and wintering waterbirds ; Raising water levels ; Habitat change
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A new, higher dam was installed at Kerkini Reservoir in 1982, causing habitat and landscape disruption. A decrease in the area of grassland and shallow water areas, the rapid disappearance of reedbeds, the appearance of beds ofNymphaea, and the disappearance of half the forest area were all observed between 1982 and 1991. With the new hydrological regime, a lacustrine system was created, with an extensive, rather deep (4–8 m), pelagic zone favorable for the development of coarse fish species throughout the year. After 1982, an increase in fishing effort and a change in the relative abundance of fish species in the catch, including the disappearance of eels and wels, were observed. The impact of the rise in the water level of breeding aquatic birds led to a general decline in species typical of marshy habitats in favor of species preferring deeper open water habitats. A decrease was recorded in bird species that feed largely on invertebrates and to a lesser extent fish (e.g., glossy ibis) and that require extensive shallow feeding areas. There was a decline in geese, whose nests were regularly flooded, and a major increase in piscivorous birds, particularly diving birds (e.g., cormorants), which prefer deeper open water and benefitted directly from the large increase in coarse fish biomass. The disappearance of birds breeding in flooded meadows (e.g., black-winged stilts) and of those restricted to reedbeds (e.g., marsh harrier) occurred from 1983. Over the same period, the changes in populations of wintering birds at Kerkini were different from those occurring in other wetlands in northern Greece. The changes recorded in the populations of wintering birds at Kerkini did not therefore result from overall regional trends but from the major habitat modifications that occurred to this wetland. As for breeding birds, strictly piscivorous species increased greatly as a result of the increased availability of fish, but also due to the appearance of many suitable night roosting sites (flooded trees) and to the great increase in the area of open water greater than 2 m deep. Today, Kerkini has become the most important breeding site in Greece for a majority of colonial waterbirds. In contrast, wintering shorebirds practically disappeared. The many changes recorded in the status of breeding and wintering birds at Kerkini can mostly be explained by the changes that occurred in the functioning of the ecosystem and in the habitat structure following the inauguration of the new hydrological regime. These changes did not all occur at the same time: some were immediate and others required a delay before they could be detected.
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  • 25
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    Environmental management 19 (1995), S. 27-37 
    ISSN: 1432-1009
    Keywords: Aquaculture ; Ecology ; Coastal zone ; Marine shrimp ; Thailand
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Rising demand for shrimp in the developed nations has helped to foster a dramatic growth in marine shrimp aquaculture, particularly in South America and South Asia. In Thailand, Marine shrimp aquaculture is now an important earmer of foreign exchange. The growth in Production has been achieved through the expansion of the culture area and the adoption of intensive production methods. The conversion of near-shore areas to shrimp culture, however, is proving to have many consequences that impinge on the environmental integrity of coastal areas. This paper reviews the development of Thailand's marine shrimp culture industry and examines the nature of the environmental impacts that are emerging. It then discusses the implications these have for rural poor and the long-term viability of the culture industry.
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    Plant ecology 116 (1995), S. 7-23 
    ISSN: 1573-5052
    Keywords: Altitudinal distribution ; Ecology ; Guatemala ; Pine communities ; Phytosociology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A phytosociological study of the juniper (locally called huito), pine (locally called sacch), pine-alder and fir forests of the Sierra de los Cuchumatanes and Cadena Volcánica in Guatemala was carried out. The Zürich-Montpellier approach was followed. In total 119 relevés were sampled and the data were organised in phytosociological tables to distinguish vegetation clusters. TWINSPAN was used to evaluate major differences among plant communities. Seven zonal plant communities were distinguished and described, namely: (1)Relbunium microphyllum-Agrostis tolucensis, (2)Werneria nubigena-Agrostis exserta, (3)Lachemilla vulcanica-Pinus hartwegii, (4)Holodiscus argenteus-Pinus hartwegii, (5)Hypnum cypressiforme-Juniperus standleyi, (6)Agave hurteri-Alnus firmifolia and (7)Sabazia pinetorum-Abies guatemalensis. This paper provides a thorough floristic characterisation of each community and outlines the major anthropogenic activities. To conclude, ecologic and floristic (dis)similarities between plant communities of the study area and those of Central Mexico, like the different altitudinal distribution of fir forests and the establishment of mid-successional communities such as theAgave hurteri-Alnus firmifolia were discussed.
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  • 27
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    Environmental biology of fishes 44 (1995), S. 263-283 
    ISSN: 1573-5133
    Keywords: Comparative methods ; Character evolution ; Phylogenetic autocorrelation ; Independent contrasts ; Least squares parsimony ; Labridae ; Feeding ; Ecology ; Functional morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Research in all fields of biology increasingly uses phylogenetic systematics to interpret biological data in an evolutionary context. It is becoming widely accepted that comparative studies of the correlation of biological features, such as ecomorphological studies, must frame their analyses within the context of a phylogenetic hierarchy rather than treating each taxonomic unit as an independent replicate. Recent methods for the interpretation of ecological and functional data in the framework of a phylogeny can reveal the degree to which ecomorphological characters are correlated with one another, and are congruent with hierarchical cladistic groups. An example of the ecomorphology of labrid fishes is used here to illustrate the application of several of these methods. The structural design and mechanics of the jaws of labrids are tested for ecomorphological associations with the natural diets of these fishes. Methods for analysis of the correlated evolution of both discrete and continuous quantitative characters within a phylogeny are practiced on a single ecomorphological data set. Techniques used include character coding, character mapping, phylogenetic autocorrelation, independent contrasts, and squared change parsimony. These approaches to diverse biological data allow the study of ecomorphology to account for patterns of phylogenetic ancestry. Biomechanics or functional morphology also plays a vital role in the determination of ecomorphological relationships by clarifying the mechanisms by which morphologies can perform behaviors important to the organism's ecology. The synthesis of systematics with biomechanics is an example of interdisciplinary study in which information exchange can elucidate patterns of evolution in ecomorphology.
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  • 28
    ISSN: 1572-9702
    Keywords: Ecology ; ticks ; Ixodes ricinus ; France
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A longitudinal survey was carried out during a 2 year period in Western France to assess the infestation level of grazing pastures byIxodes ricinus ticks. Four farms were visited once a month and each of the grazing pastures was sampled in the centre and at the border using the blanket dragging method. A total of 3562I. ricinus (34 adults, 900 nymphs and 2628 larvae) were collected and the infestation was significantly higher during the first year (p〈0.0001). The infestation level byI. ricinus varied between grazing pastures and farms. Grazing pastures in the vicinity of forest were more infested than the others, all through the study. The seasonal distribution of ticks showed peaks, with low fluctuations between farms, years and stages. Tick abundance could not be related to vegetation, but only to the vicinity of woods.
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  • 29
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    Environmental biology of fishes 43 (1995), S. 1-27 
    ISSN: 1573-5133
    Keywords: Conservation ; Extinction ; Rarity ; Biodiversity ; Breeding guilds ; Endemism ; Speciation ; Habitat degradation ; Environmental management ; Invasive fishes ; Genetics ; Ecology ; Stenotopy ; Captive propagation ; Legislation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The conservation status and factors threatening fishes worldwide are reviewed in order to introduce a series of one-page articles on ‘Threatened fishes of the world’, and to encourage the incorporation of information on threatened fishes into international conservation programmes. Information on fish extinction and threat rates are compared with those of other animal groups, and the unique characteristics of fish conservation problems are highlighted. At present 979 species of fishes are listed as threatened in the IUCN Red List and at least 36 species and three subspecies are listed as recently extinct. It is argued that these figures are probably gross underestimates and that they may mislead conservation authorities and resource users about the seriousness of the situation. Freshwater fishes may be the most threatened group of vertebrates after the Amphibia. Urgent action is required to save many narrowly endemic, stenotopic species from extinction, especially in Africa, Asia and South America. The conservation of common species that drive essential ecological processes is also important. Anthropogenic pressures, especially habitat degradation, the introduction of invasive species and pollution, on inland and coastal waters are particularly severe and many major fish communities are threatened with elimination throughout the world. The conservation of marine fishes is complicated by the fact that it is difficult to ascertain their rarity. The importance of the retention of genetic variation is highlighted, and both orthodox and innovative conservation measures are encouraged. Further research on minimum viable populations, genetics, and the factors that cause fishes to become vulnerable to extinction, is urgently required.
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  • 30
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    Environmental biology of fishes 44 (1995), S. 11-20 
    ISSN: 1573-5133
    Keywords: Morphology ; Ecology ; Form ; Biological role ; Performance ; Ontogeny ; Optimization ; Phylogeny ; Constraints ; Adaptation ; Fundamental niche ; Realized niche
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The field of ecomorphology has a long history with early roots in Europe. In this half of the century the application of ecomorphology to the biology of fishes has developed in the former Soviet Union, Poland and Czechoslovakia, The Netherlands, and in North America. While the specific approaches vary among countries, many North American studies begin by comparing morphological variation with variation in ecological characteristics at the intra or interspecific levels. These initial correlative studies form the ground work for hypotheses that explore the mechanistic underpinnings of the observed ecomorphological associations. Supporting these mechanistic hypotheses are insights from functional studies which demonstrate the limits to potential resource use resulting from a particular morphology; however, the actual resource use is likely to be more limited due to additional constraints provided by internal (e.g., behavior, physiology) and external (e.g., resource abundance, predator distribution) factors. The results from performance studies in the laboratory or field can be used to test specific ecomorphological hypotheses developed from the initial correlational and functional studies. Such studies may, but rarely do, incorporate an ontogenetic analysis of the ecomorphological association to determine their effect on performance. Finally, input from phylogenetic analyses allow an investigator to examine the evolution of specific features and to assess the rates and directionality of character evolution. The structural and ecological diversity of fishes provides a fertile ground to investigate these interactions. The contributions in this volume highlight some of the specific directions for ecomorphological research covering a variety of biological processes in fishes. These include foraging, locomotion, reproduction, respiration, and sensory systems. Running through these papers are new insights into universal ecomorphological issues, i.e., the relationships between form and ecological role and the factors that modify these relationships.
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    Environmental biology of fishes 43 (1995), S. 381-391 
    ISSN: 1573-5133
    Keywords: Fisheries ; Irrigation ; Reproductive seasonality ; Sarotherodon galilaeus ; Species richness ; Water quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis A preliminary study of the ecology and commercial fish catches was carried out in the Toho-Todougba, Ahouangan and Dati lakes (1500 ha) in southern Benin (West Africa) over a period of 18 consecutive months. Water quality, species richness, and the reproductive biology of the dominant species, Sarotherodon galilaeus, were examined. Unlike Lagoon Toho-Todougba, lakes Ahouangan and Dati are less favourable for fish production because of their high total iron content and their relative low pH. The study revealed the existence of 19 species belonging to eleven (11) families: 16 species in Lagoon Toho-Todougba,12 in Lake Ahouangan, and 7 in Lake Dati. Lakes Ahouangan and Dati had a relatively high faunal similarity whereas Lagoon Toho-Todougba exhibited a relatively low faunal similarity with the former systems. In Lagoon Toho-Todougba, six cichlid species were the most important component of the fishery: Sarotherodon galilaeus, Tilapia guineensis, T. zillii, T. mariae, Chromidotilapia guntheri, Hemichromis fasciatus. Three catfish species Chrysichthys auratus, Clarias agboyiensis, and Clarias lazera were harvested in low abundances. Some other fish, such as Polypterus senegalus senegalus, Protopterus annectens and Heterotis niloticus were captured sporadically, with H. niloticus appearing more consistently in catches than the others. Although not abundant, Gymnarchus niloticus and the African pike, Hepsetus odoe, were almost always present in the catches. Ctenopoma kingsleyae appeared only in Ahouangan. Some predatory species, such as Notopterus afer and Xenomystus nigri, are encountered only in lakes Ahouangan and Dati. In Lagoon Toho-Todougba, Sarotherodon galilaeus had a sex ratio (♂: ♀) of 0.49:1, and size at maturation was estimated as 12.3 cm TL. The spawning period extended from May to September with the peak occurring in July. Fecundity was correlated to log-body length (r = 0.74) and log-body weight (r = 0.76). Fish catches were estimated at 389 kg ha−1 year−1; about 73% of which was Sarotherodon galilaeus. The overexploitation of juvenile fish and the use of this lagoon for the irrigation of palm tree plantations have reduced fish recruitment and mean size.
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    Journal of comparative physiology 174 (1994), S. 461-467 
    ISSN: 1432-1351
    Keywords: Ecology ; Great Barrier Reef ; Lutjanidae ; Microspectrophotometry ; Visual pigments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The visual pigments in the retinal photoreceptors of 12 species of snappers of the genus Lutjanus (Teleostei; Perciformes; Lutjanidae) were measured by microspectrophotometry. All the species were caught on the Great Barrier Reef (Australia) but differ in the colour of the water in which they live. Some live in the clear blue water of the outer reef, some in the greener water of the middle and inshore reefs and some in the more heavily stained mangrove and estuarine water. All the species had double cones, each member of the pair containing a different visual pigment. Using Baker's and Smith's (1982) model to predict the spectral distribution of ambient light from chlorophyll and dissolved organic matter it was found that the absorption spectra of the visual pigments in the double cones were close to those that confer the maximum sensitivity in the different water types. Single cones contained a blue or violet-sensitive visual pigment. The visual pigments in the rods showed little variation, their wavelength of maximum absorption always being in the region 489–502 nm.
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  • 33
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    Oecologia 100 (1994), S. 397-405 
    ISSN: 1432-1939
    Keywords: Evolution of sex ; Ecology ; Clones ; Lepidoaactylus lugubris ; Gekkonidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We report differences in the thermal biology, elevational, temporal and geographic distributions of sympatric clones of the widespread asexual house gecko, Lepidodactylus lugubris. The two most common L. lugubris clones in Fiji, clones 2NA and 2NB, differ significantly in preferred temperature as measured in a laboratory heat gradient, but were similar in critical thermal maximum and minimum. Significant differences were found in the relative frequency of clones 2NA, 2NB, and a third Fijian clone, clone 3NB, at seven sites along an elevational gradient in Fiji. Clone 2NB was not collected at sites above 235 m, consistent with its higher preferred temperature, whereas clone 2NA was captured as high as 835 m. Clone 3NB was extremely rare at sealevel (1% of all individuals at three sites below 100 m), but predominated at the two highest-elevation sites (42% and 100%). Clones 2NA and 2NB did not differ significantly in their activity time or ambient activity temperature at low-elevation sites. Clone 3NB however, was active on significantly cooler nights at two of those sites. These significant inter-clonal differences in spatial and temporal distribution should allow a more complete utilization of resources by the assemblage of clones than by any single clonal genotype, and may promote coexistence of clones at a within-island and within-site scale. Clone 2NA, which is the most common clone in Fiji and has the broadest elevational distribution, also has the widest geographic distribution. It was the predominant clone at 27 of 34 sites surveyed in nine Pacific archipelagoes. This suggests that the ecological attributes that favor this clone in Fiji also favor it elsewhere in the Pacific despite differing environmental conditions and clonal composition in those areas.
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  • 34
    ISSN: 1573-5052
    Keywords: Biogeography ; Cryptogam ; Ecology ; Moss ; Plant dispersal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The distribution and frequency of bryophyte and lichen vegetation on ice-free regions of the Windmill Islands are presented using data derived from aerial photography and ground surveying. The qualitative and quantitative plant cover of sites are listed and related to the topography and major soil characteristics of each site. The richest associations of macrolichens and bryophytes occurred on the metamorphic northern peninsulas. Species richness and frequency was generally reduced on the charnockitic southern peninsula and the islands which have been deglaciated longer. Salinity varied significantly throughout the region with the highest levels in the northern islands reflecting the presence of penguin colonies. In such sites bryophytes and lichens were virtually absent. Wind blown sea-spray contributed far less salts than direct excretion from penguins. On the peninsulas snow cover and site exposure appeared to delimit plant distribution. Higher salt levels from sea-spray on the northern aspects of the peninsulas seemed to have negligible impact on vegetation patterns with the possible exception ofBiatorella cerebriformis which was encountered only inland. The total phosphorus and nitrogen levels of the skeletal soils were generally low except in eutrophic sites adjacent to penguin colonies. The vegetation patterns are discussed in terms of the climate, topography and species autecology.
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  • 35
    ISSN: 0032-8332
    Keywords: Rhinopithecus ; Distribution ; Population ; Ecology ; Conservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Yunnan snub-nosed monkey (Rhinopithecus bieti), an endangered species in China, has received more protection in theory than in practice. Therefore it is on the very verge of extinction. The population of the species was estimated less than 2,000 individuals spread in 19 distinct groups. It was confirmed that the monkey was confined to the Yunling Mountain System, the area between the Yangtze River (Changjiang, aka Jinshajiang) to the east and the Mekong River (Lancangjiang) to the west. We further concluded that a lowland belt to the east, about 100 km long and 20 – 30 km wide was not suitable habitat for the monkeys, and appeared to serve as the natural ecogeologic barrier for the species. Our results indicated that the southern limit of the distribution was at Longma (26°14′N), and that the northern limit of the distribution was at Xiaochangdu (29°20′N). The distribution area of the species was substantially smaller than previously estimated. There were substantial ecological differences between the southern and northern parts of the species range. The monkey was found only in fir-larch forest.
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    Environmental biology of fishes 39 (1994), S. 329-338 
    ISSN: 1573-5133
    Keywords: Management ; Ecology ; Traditional fishing ; Nile perch ; Tilapias ; Introduced species ; Haplochromines ; Predator-prey relationships ; Economics ; Agriculture ; Wichlum Beach ; Yala Swamp ; Conservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The introduction of the Nile perch into Lake Victoria has dramatically altered the fishery in that lake and contributed to the decline of the fishery for indigenous tilapias. One sector of the fishery in Lake Victoria has benefitted from the Nile perch introduction, although catches have declined in recent years. Inefficient enforcement of fisheries regulations has had a detrimental effect on indigenous species but may also have contributed to the recent decline in Nile perch catches. Fisheries development plans have tended to favour capital-intensive fisheries and to ignore small scale subsistence fisheries. A case study at Wichlum Beach on the Kenyan shores of Lake Victoria has revealed the efficiency of traditional fishing and fish drying methods as well as the high ecological costs of the practice of kiln-drying Nile perch. Forty-five tons of firewood are used per month at Wichlum Beach alone for kiln-drying perch. The increased economic viability of the fishery has attracted professionals into the industry and resulted in the development of an export-oriented trade. The Yala Swamp adjacent to Lake Victoria has been extensively drained as part of a large land reclamation scheme and more draining is planned. Increased environmental awareness in Kenya, and Kenya's membership in the Convention on Wetlands of International Importance, has resulted in a critical review of these plans.
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    Environmental biology of fishes 40 (1994), S. 159-174 
    ISSN: 1573-5133
    Keywords: Gulf of Carpentaria ; Estuary ; Feeding guilds ; Ecology ; Coexistence ; Molluscs ; Polychaetes ; Ariidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The diets of 13 species of ariid catfishes from the tropical waters of the Gulf of Carpentaria are described and compared. Fishes were collected from two estuaries and inshore and offshore marine areas. Up to 10 species have been recorded from a single estuary. Although all are carnivorous and consume a variety of prey, diet analyses and statistical ordination reveal three feeding guilds - piscivores, polychaete-eaters and molluscivores. The diets of most species are similar between sites. There are strong relationships between dietary guild and the size and arrangement of the palatine teeth. The piscivorous group of catfish (guild 1) have large mouths with relatively large multiple palatine tooth plates, either in a band or in a triangular pattern and armed with sharp recurved teeth. The primarily polychaete-feeding group (guild 2) have a variable mouth size but it is usually smaller than that of guild 1 fish; their palatine teeth plates are fewer and smaller, and they have small, sharp recurved teeth. Guild 3 eat mainly molluscs, and have a small mouth and large posteriorly situated palatine plates with globular, truncated teeth. Overlaps in diet between species are probably reduced by differential distribution patterns within estuaries and different habitat preferences. The mouth-width and tooth-plate arrangements of ariids in tropical Australia are suitable for dealing with broad classes of prey rather than specific items, conferring dietary flexibility. This probably optimizes the trade-off for most species between occupation of broad feeding niches and the ability to shift diet easily.
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  • 38
    ISSN: 1573-5133
    Keywords: Cyprinids ; Ethiopia ; Morphotypes ; Food-niche ; Biodiversity ; Feeding ; Evolution ; Fisheries ; Resource partitioning ; Piscivory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis In October–December 1990, the large barbs (Barbus) that contribute more than 35% of the catch in lake Tana (northern Ethiopia) were studied. Previous authors (Rüppell 1837, Boulenger 1902,1911, Bini 1940) described from 6 to 23 (sub)species for the lake. Banister (1973) lumped all of these into one subspecies: Barbus intermedius intermedius Rüppell,1837. We found that the Lake Tana Barbus could be readily categorized in at least 13 discrete morphotypes, some of which were already distinguished by local fishermen. None of the known descriptions are adequate to distinguish the barbs unambiguously, which is important for monitoring and management of developing fisheries. Intermediates between morphotypes were rare (〈 10%). By applying canonical discriminant analysis on a set of 17 morphometric characters (including some directly associated with feeding) our initial morphotype-distinction was confirmed. Also, differences between the morphotypes in distribution, related to depth and substratum were found, as well as differences in intestinal contents, a key to the food-niche. The high number of piscivorous morphotypes (8 out of 13) was striking as piscivory is relatively rare among cyprinids. Piscivory was found to be highly correlated with morphological (feeding related) characters. The presence of discrete morphotypes, that also differ in food-niche and distribution, strongly suggests that several distinct populations exist, that may be (partly or completely) reproductively segregated. Knowledge about these populations, that may represent separate units of fish stock, is of crucial importance for the management of sustainable fisheries and protection of the biodiversity in Lake Tana. It is possible that several species or even a unique cyprinid species flock are present, that urgently need protection.
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  • 39
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    AI & society 7 (1993), S. 117-126 
    ISSN: 1435-5655
    Keywords: Ecology ; Causal science ; Human-centred technology ; Human purpose ; Taylorism ; Belief systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract If one interprets the ‘ecology of technology’ as the study of technology in relation to its environment, there are two important levels at which this study can be made. It is possible to consider the different environments in Europe, Japan and the USA, and look for the different technological influences which accompany them. At a more general level, one can look at those factors which are common to all three environments, and which are associated with generic similarities in the technology of all three areas. The paper considers both aspects as they have been experienced in Europe in some attempts to develop a ‘human-centred technology’.
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    Oecologia 93 (1993), S. 349-355 
    ISSN: 1432-1939
    Keywords: Vesicular-arbuscular mycorrhizas ; Ecology ; Infectivity ; Specificity ; Selection
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    Topics: Biology
    Notes: Abstract Specificity in vesicular-arbuscular mycorrhizas (VAM), arising from selection favouring host plant/mycorrhizal fungus associations in which both organisms receive benefit, might have a significant influence on interactions between co-existing plant species. In an attempt to detect such specificity root inoculum of four tempt to detect such specificity root inoculum of four plant species, harvested from a species-rich grassland on three dates during the plant growth season, was used to infect the same plant species grown in pots. The rate and overall level of infection was different according to inoculum source and the time of year in which the inoculum was harvested, i.e. temporal variation in VAM infectivity occurs. However, there was no evidence for either specificity or mycorrhizal benefit. Inoculum produced during this experiment was used to infect “bait” Trifolium pratense plants and protein patterns of these roots indicated that a number of biochemically different endophytes were present, both within the inoculum of the four plant species but also within inoculum from one plant species. Temporal variation in mycorrhizal infectivity could be important for mycorrhizal propagation in the field. However, the lack of evidence, in this study, for specificity of VAM or an obvious nutritional benefit to plants with mycorrhizas make the role of mycorrhizas in this community difficult to interpret.
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    Plant ecology 107-108 (1993), S. 3-13 
    ISSN: 1573-5052
    Keywords: Ecology ; Frugivory ; Seed dispersal ; Tropics
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    Topics: Biology
    Notes: Abstract I explore the ‘specialization’ versus ‘generalization’ paradigm in frugivory and seed dispersal. This view predicts that some tropical trees produce nutritious fruits adapted for use by a small coterie of specialized frugivores that provide reliable seed dissemination. Other tree species are expected to offer superabundant fruits of lower nutritional reward, relying instead on common opportunistic frugivores that are individually less reliable, but collectively disperse seeds effectively. Though widely referenced, many aspects of ‘the paradigm’ are untested with tropical trees and avian frugivores, primarily because plant ecologists rarely determine whether ‘specialist’ or ‘generalist’ foragers are responsible for different patterns of seed distribution, while students of foraging behavior rarely determine the effects seed dispersal by different animals for survival of seeds or seedlings of ‘specialist’ or ‘generalist’ trees. Ecological paradigms provide alternative hypotheses, without evolutionary arguments. ‘Keystone’ species have ecological effects disproportionate to their abundance; it is important for management considerations to know whether fruiting trees or frugivores serve as keystone mutualists in tropical forests. Alternatively, the extent to which vertebrate seed dispersers influence density-dependent seed, seedling, sapling, or adult mortality may have important consequences for spatial dispersion and population dynamics of tree species in tropical forests.
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    Biology and philosophy 8 (1993), S. 359-384 
    ISSN: 1572-8404
    Keywords: Ecology ; evolution ; competition ; theory testing ; modeling
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    Topics: Biology , Philosophy
    Notes: Abstract There is a long history of controversy in ecology over the role of competition in determining patterns of distribution and abundance, and over the significance of the mathematical modeling of competitive interactions. This paper examines the controversy. Three kinds of considerations have been involved at one time or another during the history of this debate. There has been dispute about the kinds of regularities ecologists can expect to find, about the significance of evolutionary considerations for ecological inquiry, and about the empirical credentials of theoretical studies of competition. Each of these elements is examined with an eye toward gaining philosophical clarification of the issues involved. In the process, certain shortcomings of contemporary philosophical theories are revealed. In particular, I argue that plausibility arguments based on background considerations are an important part of the model building tradition, but that current accounts of the structure and evaluation of scientific theories do little to illuminate this side of theoretical ecology.
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    Plant ecology 107-108 (1993), S. 149-162 
    ISSN: 1573-5052
    Keywords: Ecology ; Frugivory ; Herbivory ; Seed dispersal ; Seedling Ecology ; Virola
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    Topics: Biology
    Notes: Abstract This paper explores the causes and consequences of seed and seedling mortality of the tree Virola nobilis (Myristicaceae) Central Panama in order to understand the advantage to local seed dispersal by birds and monkeys. Post-dispersal mortality due to insects (primarily Conotrachelus spp., Curculionidae) accounts for 30–35% of seed and seedling death during the first 12 weeks after seed fall. Because more seeds and seedlings are killed under and near fruiting trees than 15–45 m away, seed dispersal confers a 20–40 fold advantage on seeds carried 45 m from fruiting adults. In contrast, 〉60% of seed and seedling death during the first year is due to seed predation by mammals, with 〉90% due to mammals among the 〈2% seeds that survive until maternal endosperm is exhausted ±12 weeks after seed fall. Mortaliy due to mammals is independent of distance from parent trees, confering no advantage to seed dispersal. Insects account for variation in mortality attributable to distance effects, mammals to between site effects. Early weevil infestations put a premium on seed removal by large birds (Ramphastos swainsonii, R. sulfuratus, Penelope purpurascens), which carry 〉50% of the seeds that they eat 〉40 m, as compared with smaller birds (Baryphthengus martii, Tityra semifasciata, Trogon massena) and monkeys (Ateles geoffroyi), which leave most or all of the seeds that they eat under or near the tree crown.
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    AI & society 7 (1993), S. 109-116 
    ISSN: 1435-5655
    Keywords: Ecology ; Technology ; Demilitarisation ; Euro-centrism ; Techno-giants ; Humancentred
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    Topics: Computer Science
    Notes: Abstract Science and technology are on trial due to the rapid changes — neither university nor science lead developments in technology, the most advanced military technology has lost linkages with industries, the widened North-South gaps — they are all sources of crisis in the global ecological balance. The Euro-centric universalism is useless to solve the global technology problems.
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    Environmental biology of fishes 37 (1993), S. 25-46 
    ISSN: 1573-5133
    Keywords: Ecology ; Seasonality ; Catch-rates ; Lake levels ; Oxygen ; Predators ; Size-at-maturity ; Growth ; Mortalities
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    Topics: Biology
    Notes: Synopsis Three observed dynamic aspects of the Nile tilapia population around Ferguson's Gulf at Lake Turkana, Kenya are evaluated and discussed: the seasonality in catch rates, the enormous inter-annual abundance variations, and the large changes in median size at first maturity. A clear understanding of the regulating mechanisms behind these features has never been achieved, although seasonal changes in the hydrology of shallow sheltered refuges seems to play an important role. This paper suggests a further holistic approach taking the impacts and interrelationships of both the primary productivity and the various predators into account. A synthesizing ecological hypothesis is elaborated, which concludes that most observations on the tilapia dynamics can be explained from changes in the oxygen concentrations and size-specific mortality pressures. Variations in these two proximate factors can ultimately be explained by the floodplain-type fluctuations in the Ferguson's Gulf environment.
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  • 46
    ISSN: 0032-8332
    Keywords: Macaca sylvanus ; Ecology ; Demography ; Migration ; Group fission ; Population genetics
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    Topics: Biology
    Notes: Abstract Over a 9-year period from 1982 to 1990 ecological and demographic data were collected on two genetic isolates of Barbary macaques (Macaca sylvanus) in Algeria, from the deciduous oak-forest of Akfadou and from the evergreen cedar-oak forest of the National Park Djurdjura. Macaques at Djurdjura profit from more suitable ecological conditions and have a higher rate of population increase as well as a higher male migration rate than those at Akfadou. Genetic data, gained from 23 genetic markers (blood proteins), proved to be highly influenced by the demographic structure of the groups. The macaque populations of Akfadou and Djurdjura have become genetically differentiated. Group fission, coupled with founder effect (genetic drift) and kin-structured (matrilineal) separation, resulted in a priori genetic diversity between one newly-established group and its parent group.
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  • 47
    ISSN: 1432-1009
    Keywords: Fisheries ; Phosphorus ; Contaminants ; Ecosystem ; Management ; Simulation model ; Great Lakes
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    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A simulation model was developed to describe linkages among fish food web, nutrient cycling, and contaminant processes in the southern basin of Lake Michigan. The model was used to examine possible effects of management actions and an exotic zooplankter (Bythotrephes) on Lake Michigan food web and contaminant dynamics. The model predicts that contaminant concentrations in salmonines will decrease by nearly 20% ifBythotrephes successfully establishes itself in the lake. The model suggests that this decrease will result from lowered transfer efficiencies within the food web and increased flux of contaminants to the hypolimnion. The model also indicates that phosphorus management will have little effect on contaminant concentrations in salmonines. The modeling exercise helped identify weaknesses in the data base (e.g., incomplete information on contaminant loadings and on the biomass, production, and ecological efficiencies of dominant organisms) that should be corrected in order to make reliable management decisions.
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    Journal of mathematical biology 30 (1992), S. 413-436 
    ISSN: 1432-1416
    Keywords: Travelling waves ; Integrodifferenceequations ; Bifurcations ; Diffusion ; Ecology
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    Topics: Biology , Mathematics
    Notes: Abstract Integrodifference equations are discrete-time models that possess many of the attributes of continuous-time reaction-diffusion equations. They arise naturally in population biology as models for organisms with discrete nonoverlapping generations and well-defined growth and dispersal stages. I examined the varied travelling waves that arise in some simple ecologically-interesting integrodifference equations. For a scalar equation with compensatory growth, I observed only simple travelling waves. For carefully chosen redistribution kernels, one may derive the speed and approximate the shape of the observed waveforms. A model with overcompensation exhibited flip bifurcations and travelling cycles in addition to simple travelling waves. Finally, a simple predator-prey system possessed periodic wave trains and a variety of travelling waves.
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    Plant ecology 98 (1992), S. 33-41 
    ISSN: 1573-5052
    Keywords: Chorology ; Ecology ; Lithology ; New association ; Numerical classification ; Saxifraga depressa ; Saxifragetum depressae ; Scree ; Syntaxonomy
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    Topics: Biology
    Notes: Abstract Saxifraga depressa grows only on the summits of eleven siliceous massives in the western Dolomites. It is restricted to the habitat of steep N-faced screes lying above 2000 m. Syntaxonomically, Saxifraga depressa characterizes the association Saxifragetum depressae which is here described for the first time with two subassociations. With respect to the closely allied Oxyrietum digynae, the Saxifragetum depressae colonizes debris richer in fine material. The soil pH in the habitats of the Saxifragetum depressae varies from acid to slightly basic, mainly as a result of lithological differences in the parent rocks. The habitats having a subneutral or basic soil are colonized by a well-defined subassociation of the Saxifragetum depressae, which is differentiated by some basiphilous species.
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    Plant ecology 99-100 (1992), S. 19-34 
    ISSN: 1573-5052
    Keywords: Biogeography ; Ecology ; Paleoecology ; Variability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Quercus ilex sensu lato plays an important role in Western Mediterranean ecosystems, but is poorly developed in the Eastern Mediterranean where it is often replaced by Quercus calliprinos. The occurrence of Quercus ilex in the different bioclimates and their thermic subdivisions is presented on a small scale. Under certain geographical and ecological conditions, Quercus ilex participates in the organization of vegetation ecosystems from the meso-Mediterranean to the oro-Mediterranean altitudinal zones. Quercus ilex imposes microclimatic constraints on its associated species; it thus organizes and original understory vegetation structure (ethological groups) which will be defined in this study. One of the reasons for the success of Quercus ilex stems from its remarkable resistance to ecological constraints. A broad synthetic presentation of foliar area index variations in relation to different types of stress serve as a basis for an explanation of the sclerophyllous model in the Mediterranean region. Finally, historical factors are outlined as being critical characteristics in the determination of the present organization and spatial structure of Quercus ilex ecosystems. These considerations will be analyzed from a paleobioclimatical point of view, including data related to human pressure.
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    Primates 33 (1992), S. 305-314 
    ISSN: 0032-8332
    Keywords: Infant development ; Parental care ; Propithecus ; Reproductive costs ; Ecology
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    Topics: Biology
    Notes: Abstract This paper reports the results of a three-month field study on parental care and infant development in the diademed sifaka (Propithecus diadema edwardsi) in the primary rain-forest of south-eastern Madagascar. They are compared with a three-and-a-half-month study of captive white sifaka (Propithecus verreauxi coquereli) in the Duke University Primate Centre. Records were taken by means of focal animal and instantaneous sampling. In both species the mother was the primary carrier and caretaker; theP. verreauxi father carried the infant significantly more than did any animal other than the mother in theP. diadema group. The infantP. verreauxi spent less time off the mother than didP. diadema from week 4 through week 10. It is concluded thatP. verreauxi shows more non-maternal care thanP. diadema and also develops at a slower rate. The difference in the two species' habitats is discussed as a possible cause.
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    Environmental biology of fishes 33 (1992), S. 153-165 
    ISSN: 1573-5133
    Keywords: Neuroanatomy ; Ecology ; Vision ; Olfaction ; Gustation ; Plasticity ; Adaptation ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The size of seven neural structures was compared in 51 species of Notropis, Pteronotropis, Cyprinella, Luxilus, Lythrurus, and Hybopsis, and related to the turbidity of the species& habitat. This last parameter was assessed for each species by personal communication with 42 ichthyologists. To control for size differences among species, all analyses were performed on the residuals from a regression of each character on standard length. Principal components analysis (PCA) of the residuals produced four significant PC-axes that together explained 65% of the total variation represented in the original variables. The size of brain structures concerned with vision, olfaction, and gustation was correlated with habitat turbidity. Two-way Analyses of Covariance (ANCOVAs) revealed significant differences between species in the size of all structures. Sexual dimorphism was found in the size of the olfactory bulb and the cerebellum, and significant two-way interactions (species vs. sex) were detected for the telencephalon, optic lobes, cerebellum, vagal lobe, and the eye. Cluster analysis indicated that neither similar turbidity preference nor shared phylogeny is alone sufficient to explain the observed differences in brain morphology.
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    Environmental biology of fishes 35 (1992), S. 187-203 
    ISSN: 1573-5133
    Keywords: California ; Elasmobranchs ; Exploitation ; Fisheries ; Life history ; Tagging ; Triakidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The age, growth, and sexual maturation of the leopard shark, Triakis semifasciata, from central California were studied. Growth band counts in vertebral centra of 162 leopard sharks produced von Bertalanffy growth curves with L∞, K. and to parameters of 1536 mm. 0.082, and -2.31, respectively, for both sexes combined. The L8 value for females (1602 mm TL) was slightly but insignificantly higher than for males (1499 mm TL), but the K and to values were almost identical. Seasonal changes in size modes of young-of-the-year leopard sharks, centrum edge characteristics, and growth and tetracycline mark-recapture from the field were used to validate annual deposition of vertebral centrum band pairs. Sexual maturity was evaluated by the gonads and presence of sperm and eggs; males mature at 7 yr and at about 63% of asymptotic length, and females mature at 10 yr, and at about 72% of asymptotic length. This slow growth, late maturity, and relatively low fecundity may increase their susceptibility to over-exploitation.
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    International journal of biometeorology 35 (1991), S. 239-251 
    ISSN: 1432-1254
    Keywords: Modelling ; Ecology ; Response functions
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    Topics: Geography , Physics
    Notes: Abstract This article describes the further development and new applications of the already well-known method of response functions. This method is used to present the quantitative evaluation of the reactions of various ecological and biological systems to environmental impacts. Two ecological problems were chosen as examples: the model of growth and development of cereal crops and the model of pollutant dynamics in the elementary ecosystem. In each case the results are given of the evaluation of parameters and the testing of models. It is shown that the method of response functions allows resolution of the wide range of ecological problems with sufficient accuracy, and some new theoretical results are presented. For example, based on the existing hypotheses of higher plant development, a biological time scale has been worked out. The method was elaborated to determine the minimum time of development, which is a genetically stipulated characteristic of a species and is realized when all environmental factors are optimal.
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  • 55
    ISSN: 1432-1939
    Keywords: Ecology ; Butterfly ; Oeneis chryxus ; Population structure ; Population dynamics
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    Topics: Biology
    Notes: Summary This paper describes temporally varying determinants of the spatial distribution of adults in an insect population and the relationship between that distribution and the mating system. Male Oeneis chryxus butterflies were distributed nonrandomly throughout a sloping Colorado meadow divided horizontally by a dirt road into an upper and lower slope. Over an eight-year period of intensive study, the proportion of males located on the road, the upper slope, and the lower slope varied as a function of population size and sex ratio. In each year, more than half of the male population aggregated on sections of the road in a distinct and recurring pattern that was not correlated with the distribution of any food resource or thermal regime. Females were usually extremely scarce and not distributed in any pattern apparent from the few observations of them. Areas densely occupied by males were associated with visual landmarks. We hypothesize that the male distribution is determined by a pattern of movement of receptive females toward these landmarks. The road offers a thermally favorable environment with an unobstructed view in which to await the passage of scarce females. The mating system in this population has several lek-like features and supports the prediction that landmark mating is a favored strategy under conditions of female scarcity and wide dispersal of resources.
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  • 56
    ISSN: 1432-1939
    Keywords: Mangroves ; N2-fixation ; Ecology ; Nutrient cycling ; Rhizosphere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Heterotrophic dinitrogen fixation in root associations of successional stages of the tropical mangrove plant community at the Ganges river estuary in India was investigated by excised-root acetylene reduction assay, and enumeration and identification of diazotrophic bacteria from sediment, root and tidal water samples. High to very high rates of nitrogenase activity (64–130 nmol C2H4/g dry root/h) were associated with washed excised roots of seven common early-successional mangrove species at the inundated swamps. Declining, late-successional mangroves at the occasionally inundated ridges had considerably lower values and the “declined” mangroves and other non-littoral species at embankment protected highlands had very low to insignificant values of root nitrogenase activity. Total and inorganic nitrogen contents of the mangrove sediments were low and were positively related to the stages of physiographic succession. Plant-associated sediments of particularly the old formation swamps had very high C/N ratios. Nine isolates of nitrogen-fixing bacteria belonging to all known O2 response groups were distinguished from a large population of diazotrophs associated with roots of mangroves and other associate plant species of the community. The isolates differed with respect to their N2-fixation efficiency and halotolerance in pure culture. There was no specificity of any of the bacterial isolates to any of the plant species of the community but a higher number of efficient isolates were seen to be associated with mangroves at the swampy succession. Sediment-free tidal water also contained a large population of microaerophilic and anaerobic N2-fixing bacteria.
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  • 57
    ISSN: 0032-8332
    Keywords: Crested gibbons ; China ; Behavior ; Ecology ; Monogamy
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    Topics: Biology
    Notes: Abstract The black-crested gibbon,Hylobates concolor, is one of the few species of gibbons that has not yet been the subject of a long term field study. Field observations in the Ai Lao and Wu Liang Mountains of Yunnan Province, China indicate that in this area the habitat and ecology of this species differ markedly from those of other gibbons that have been studied to date. These differences are correlated with some behavioral differences. In particular, these gibbons apparently have greater day ranges than other gibbons. It has also been suggested that this species lives in polygynous groups. To demonstrate this requires observation of groups with two or more females with young. Our own observations and those from other recent studies suggest that there are alternative explanations consistent with available data.
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    Environmental biology of fishes 30 (1991), S. 253-271 
    ISSN: 1573-5133
    Keywords: Rockfish ; Longevity ; Reproductive value ; Fisheries ; Scorpaenidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The characteristics of lightly and heavily exploited Pacific ocean perch,Sebastes alutus, stocks are evaluated relative to the predictions of life history theory. These long-lived species (50–100 year lifespan) show limited phenotypic plasticity and have little buffering against the effects of reduced lifespan. Reduced stock abundance has generated some compensatory increase in growth rate. Length at first maturity varies only slightly with increased growth rate, although age at maturity may decrease by 1–4 years. Grooth increases yield larger (15–20%) size at age and increased reproductive effort at younger ages, but lower size-specific fecundity for these faster-growing fish. This suggests an energy allocation protocol favouring growth over reproduction in these long-lived animals. Rockfishes have late recruitment to fisheries (ages 10–15), and the detection time for results of management actions is equally long. Their vulnerability to overfishing means that indices of population changes, more representative of fishing effects than the catch rate index presently used, are required. Reproductive value indices are shown to be extremely sensitive and continuous with population abundance changes. Their incorporation into monitoring programs would permit more timely evaluation of management actions. Management policies developed for shorter-lived species are shown to be inappropriate for rockfishes. The need for an improved match in the time frame of the species' life history, and that of management strategies, is stressed.
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    Environmental biology of fishes 31 (1991), S. 55-74 
    ISSN: 1573-5133
    Keywords: Floodplain fisheries ; Subsistence fisheries ; Feeding ; Condition ; Reproduction ; Ecology ; Niches ; Arius ; Hemipimelodus ; Pisces ; Ariidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Ariids accounted for approximately 25% of the weight of catches and landings from rivers and lakes in the floodplain region (= 50% weight of native species). Habitat preferences were:A. solidus, lakes and rivers;A. utarus, rivers and occasionally lakes;A. coatesi andA. velutinus, rivers only;A. nox, lakes and floodplain.A. solidus andA. utarus occasionally entered the floodplain but onlyA. nox exhibited any, albeit modest, affinity for this environment. In general, the fishes showed no marked seasonality relating to the flood cycle: in four species slight increases in feeding, condition, breeding and fat deposition occurred during the dry season whilst onlyA. nox showed modest increases in these parameters during the flood season due to its increased feeding on the floodplain at that time. All species are omnivorous but diets differed according to morphology and habitat preferences. Diet overlap was greatest amongstA. coatesi, A. solidus andA. utarus which fed mainly on prawns and a variety of other plant and animal matter.A. nox is a specialised filter-feeder consuming mainly small crustaceans and small insect larvae.A. velutinus fed mainly on large insect larvae and emergent and terrestrial insects and its diet excluded prawns.A. solidus and, especially,A. utarus also fed on fish scales. Feeding commenced immediately after hatching while free embryos were still in the male parent's mouth. Large amounts of fat were stored prior to brooding during which time males fast. The reproductive style of ariid catfishes limits their colonisation of the floodplain and is a constraint to increased fisheries exploitation of the stocks. The importance of ariids to the local fishery and nutrition (fat) for the local people should be recognised.
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    Biology and fertility of soils 9 (1990), S. 93-94 
    ISSN: 1432-0789
    Keywords: Voucher specimens ; Biology ; Ecology ; Taxonomy ; Soil animals ; Soil biologist
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Voucher specimens ensure that the identity of organisms studied in the field or in laboratory experiments can be verified, and ensure that new species concepts can be applied to past research. Guidelines on the collection, preparation, and deposition of voucher specimens and means of referral to them are given. Type specimens and the nomenclature of species names are briefly described.
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    Oecologia 83 (1990), S. 14-19 
    ISSN: 1432-1939
    Keywords: Nematodes ; Maturity ; Ecology ; Colonization ; Biomonitoring
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Nematode assemblages constitute a potential instrument for assessing the quality of submersed, temporarily submersed, and terrestrial soils and for the development of an ecological typology and biomonitoring system. Interpretation of physical or pollution-induced disturbances has hitherto mainly been based on changes in diversity, dominance patterns or percentage of dorylaimids (Adenophorea). The maturity index, based on the nematode fauna, is proposed as a gauge of the condition of the soil ecosystem. Values on a coloniser/persister scale are given for nematodes that occur in The Netherlands. The possibilities of the use of this index are demonstrated by a retrospective interpretation of some literature data. The use of nematodes in environmental studies is discussed.
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    Environmental management 14 (1990), S. 359-365 
    ISSN: 1432-1009
    Keywords: Planning ; Ecology ; Rest camp ; Natural Resources ; Zoning ; Landscape facets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The premise of this article is that the planning and design of new rest camps in conservation areas should be based on ecological principles in such a way that the plant ecology within the camp be an integral part and extension of the natural ecology of its immediate vicinity. This is desirable so that visitors to the camp will be provided not only with facilities for resting, eating, and sleeping, but also be able to enjoy and study the natural environment in a relaxed atmosphere. The Berg-en-Dal rest camp, which was established in Kruger National Park, was planned in such a way and designed according to the principles outlined by the authors in a companion article. The planning included six zones: a control zone, day visitor zone, overnight visitor zone, staff accommodation zone, recreation zone, and service zone. The point is stressed that plant species selected to be used as additional vegetation to those already growing in the camp were endemic to the nine landscape facets identified in the camp. The design allowed for separation of the various land-use zones in such a way that they would complement each other rather than be a hindrance to each other. The camp has been built according to the plans included in this article and has proved to be a great success. The conclusion is drawn that the planning principles are sound and should be used in the future for the planning and design of rest camps for conservation areas in South Africa.
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    Environmental management 14 (1990), S. 349-358 
    ISSN: 1432-1009
    Keywords: Conservation ; Ecology ; Planning ; Land use ; Zoning ; Camp siting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract This article discusses an application of the ecological planning model proposed by Van Riet and Cooks. The various steps outlined in this model have been applied to Kruger National Park in South Africa. The natural features of Kruger National Park, which form the basis of such an ecological planning exercise and from which the various land use categories, values, and zoning classes can be determined, are discussed in detail. The suitability of each of the various features is analyzed and a final zoning proposal for Kruger National Park is suggested. Furthermore a method for selecting a site for a new camp is illustrated by referring to the site for the new Mopane rest camp which is now under construction in the Kruger National Park. The conclusion is reached that the proposed ecological planning model can be used successfully in planning conservation areas such as Kruger National Park and for the selection of the most desirable sites for the establishment of new rest camps. Its suitability as a practical model in such planning exercises is proven by the fact that the siting proposals of two new camps based on this model have been accepted by the National Parks Board, the controlling body of Kruger National Park.
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  • 64
    ISSN: 1432-1343
    Keywords: Analysis of variance ; Choropleth map ; Ecology ; Genetics ; Geography ; Permutation test ; Spatial autocorrelation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Description / Table of Contents: Résumé Cet article présente une solution au problème de l'analyse de variance, pour certains cas où la variable à analyser est spatialement autocorr élée alors que le critère de classification représente des sous-régions connexes du territoire à l'étude. On sait que les méthodes classiques d'analyse de variance ne sont pas applicables dans ce type de situation puisque la condition d'indépendance des échantillons n'est pas respectée; l'autocorrélation positive réduit la variabilité intragroupe, si bien que la quantité relative de variabilité intergroupe s'en trouve artificiellement augmentée. Cette situation correspond en réalité à une vaste catégorie de problèmes en génétique des populations, en écologie et dans d'autres branches de la biologie, ainsi qu'en épidémiologie, en géographie, en géologie, en science économique, en science politique et en sociologie. Ce nouveau test appartient à la famille des tests par permutation. Nous calculons la somme des dispersions intragroupes et testons contre une distribution de référence obtenue en permutant les régions géographiques un grand nombre de fois sur la carte. La véritable difficulté de ce test est d'ordre algorithmique, puisqu'il n'est pas facile de permuter des régions sur une carte, de façon à ce que chaque groupe demeure connexe, et que la carte permutée occupe le même espace total que la carte d'origine. Cet article présente la théorie, les algorithmes, ainsi que des résultats obtenus par cette méthode. Un programme écrit en PASCAL est disponible.
    Notes: Abstract The classical method for analysis of variance of data divided in geographic regions is impaired if the data are spatially autocorrelated within regions, because the condition of independence of the observations is not met. Positive autocorrelation reduces within-group variability, thus artificially increasing the relative amount of among-group variance. Negative autocorrelation may produce the opposite effect. This difficulty can be viewed as a loss of an unknown number of degrees of freedom. Such problems can be found in population genetics, in ecology and in other branches of biology, as well as in economics, epidemiology, geography, geology, marketing, political science, and sociology. A computer-intensive method has been developed to overcome this problem in certain cases. It is based on the computation of pooled within-group sums of squares for sampled permutations of internally connected areas on a map. The paper presents the theory, the algorithms, and results obtained using this method. A computer program, written in PASCAL, is available.
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    Environmental biology of fishes 28 (1990), S. 33-75 
    ISSN: 1573-5133
    Keywords: Sharks ; Rays ; Chimaeras ; Chondrichthyes ; Evolution ; Success ; Diversity ; Ecology ; Ecomorphotypes ; Reproductive modes ; Conservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Cartilaginous fishes, the sharks, rays and chimaeras (class Chondrichthyes), are a very old and successful group of jawed fishes that currently contains between 900 and 1100 known living species. Chondrichthyians show a high morphological diversity during most of their evolutionary career from the Paleozoic to the present day. They are relatively large predators which have remained a major, competitive element of marine ecosystems despite the varied rivalry of numerous other marine vertebrate groups over at least 400 million years. Although restricted in their ecological roles by morphology, reproduction and other factors, the living cartilaginous fishes are highly diverse and show numerous alternative life-history styles which are multiple answers to exploiting available niches permitted by chondrichthyian limitations. Chondrichthyians living and fossil can be divided into at least eighteen ecomorphotypes, of which the littoral ecomorphotype is perhaps the most primitive and can serve as an evolutionary origin for numerous specialist ecomorphotypes with benthic, high-speed, superpredatory, deep-slope and oceanic components. Reproductive modes in cartilaginous fishes are of six types, ranging from primitive extended oviparity through retained oviparity and yolk-sac viviparity (previously ovoviviparity) to three derived forms of viviparity. Reproductive modes are not strongly correlated with ecomorphotypes and with the phylogeny of living elasmobranchs. The success and importance of cartilaginous fishes is largely underrated by marine biologists and by the public, and requires new and ‘heretical’ emphasis to overcome the present inadequacies of chondrichthyian research and the problems of overexploitation that cartilaginous fishes face.
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  • 66
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    Environmental biology of fishes 28 (1990), S. 179-187 
    ISSN: 1573-5133
    Keywords: Lakes ; Floodplains ; Rivers ; Perturbation ; Resilience ; Resistance ; Guarders ; Non-guarders ; Bearers ; Altricial ; Precocial ; Predictable ; Unpredictable ; Ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The continent of Africa has a wide variety of inland waters ranging from rift valley lakes to endorheic and coastal lakes, floodplains and rivers. This paper makes a preliminary comparison of the number of species in different eco-ethological sections of the reproductive guild categories of non-guarders, guarders and bearers in ancient African Great Lakes (Malawi, Victoria and Tanganyika), fluctuating endorheic lakes (Ngami, Chad and Chilwa), typical rivers (Orange-Vaal, Limpopo, Phongolo, Sabi-Lundi, Middle and Lower Zambezi, Kafue, Cunene, Okavango, Niger, Luongo, Lower Zaire) and wetlands (Okavango Delta and Kafue floodplain). The results indicate that the highest percentage of bearers and guarders is found in the ancient African Great Lakes, which are characterised by relatively predictable physico-chemical regimes, whereas a higher percentage of non-guarders is found in the rivers and wetlands, which have less predictable physico-chemical regimes. The management implications of this observation are discussed, and the usefulness of the species as a unit in ecology is assessed.
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  • 67
    ISSN: 1573-5133
    Keywords: Exotic fishes ; Overfishing ; Predation ; Competition ; Fisheries management ; Conservation ; Ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis There has been a decline, and in some cases an almost total disappearance, of many of the native fish species of lakes Victoria and Kyoga in East Africa since the development of the fisheries of these lakes was initiated at the beginning of this century. The Nile perch, Lates niloticus, a large, voracious predator which was introduced into these lakes about the middle of the century along with several tilapiine species, is thought to have caused the reduction in the stocks of several species. But overfishing and competition between different species also appear to have contributed to this decline. By the time the Nile perch had become well established, stocks of the native tilapiine species had already been reduced by overfishing. The Labeo victorianus fishery had also deteriorated following intensive gillnetting of gravid individuals on breeding migrations. L. niloticus is, however, capable of preying on the species which haven been overfished and could have prevented their stocks from recovering from overfishing. L. niloticus is also directly responsible for the decline in populations of haplochromine cichlids which were abundant in these lakes before the Nile perch became established. Even without predation by Nile perch, it has been shown that the haplochromine cichlids could not have withstood heavy commercial exploitation if a trawl fishery had been established throughout Lake Victoria. Their utilisation for human food has also posed some problems. The abundance of the native tilapiine species may also have been reduced through competition with introduced species which have similar ecological requirements. At present, the Nile perch and one of the introduced tilapiine species, Oreochromis niloticus, form the basis of the fisheries of lakes Victoria and Kyoga.
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  • 68
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    Environmental biology of fishes 27 (1990), S. 273-283 
    ISSN: 1573-5133
    Keywords: Ecology ; Larvae ; Juveniles ; Recruitment ; Nursery areas
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    Topics: Biology
    Notes: Synopsis Several freshwater species use the Kyrönjoki River estuary as a spawning and nursery area. The main reasons for this seem to be the morphology of the estuary, the abundance of shelter provided by aquatic macrophytes, high food production and favourable temperature conditions. Acidification of the estuary due to drainage from acidic soils has made part of the estuary unsuitable for fish reproduction. In addition, year to year fluctuations in the acidity of the estuarine water have affected the reproductive success of several species. The severity of the effects of the acidification at the population level is determined by the spatial and temporal distribution of the larvae and juveniles.
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  • 69
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    Environmental biology of fishes 27 (1990), S. 303-308 
    ISSN: 1573-5133
    Keywords: Fish introductions ; Africa ; Cichlids ; Barbus ; Haplochromis ; Lake management ; Fisheries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Cyprinid fishes apparently constituted the major part of the original fish fauna in Lake Luhondo, Rwanda, at least until 1934. At that time only three species, all cyprinids, were known from the lake:Barbus neumayeri, a small barbel, very common in the lake (described from the lake asBarbus luhondo) and two larger cyprinid species:Barbus microbarbis andVaricorhinus ruandae. These two large species were probably not very common in the lake. Between 1935 and 1938 some youngTilapia were introduced into Lake Luhondo. Since then and certainly since 1952 the large cyprinids seem to have disappeared completely from the lake. The smallBarbus neumayeri has become extremely rare; at present it survives only in some small tributaries of the lake. In the lake itselfTilapia andHaplochromis species are now the dominant fauna. A survey of the available information is given.
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    Aquatic sciences 51 (1989), S. 235-248 
    ISSN: 1420-9055
    Keywords: Ecology ; ciliates ; river ; water quality ; sphaerotilus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Since sewage treatment plants are most effective in Switzerland, the micro-benthic communities in receiving running waters have changed considerably. From January 1980 to September 1981 the periphyton communities in 13 Swiss streams and rivers were monthly investigated. The NH4-N concentration in these waters varied between 0.015 and 1.0 mg/l. Four typical communities of microorganisms were found: In unpolluted running waters mainly small vagile ciliates were abundant; in slightly polluted waters peritricha (in the presence of bacteria) were found; in moderatly polluted waters peritricha in combination of few hymenostomata and Sphaerotilus could grow when bacteria and some degredable organic material where present; in polluted waters the well-known Spaerotilus-community (after Liebmann) could be found. The microscopic as well as the macroscopic aspect should be considered to qualify the degree of pollution in streams and rivers.
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  • 71
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    Oecologia 79 (1989), S. 417-426 
    ISSN: 1432-1939
    Keywords: Demography ; Ecology ; Frugivory ; Seed dispersal ; Tropics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Fruit-eating animals deposit viable seeds in patterns that determine the conditions under which seeds and seedlings live or die. Many tree species are scatter-dispersed by birds, bats, or other small frugivores that regurgitate, defecate, or drop seeds singly or in pairs. These scatterdispersed plant species normally recruit as isolated individuals, and are unlikely to evolve exceptional resistance to herbivores, pathogens, or to other sources of density-dependent seed or seedling mortality. Other tree species are clump-dispersed by larger terrestrial or arboreal frugivores that defecate seeds in masses which produce bouquets of seedlings. Because their seeds invariably germinate in close proximity to other seedlings, clump-dispersed species necessarily evolve chemical or mechanical defenses against seed predators, pathogens, and herbivores that act in a densitydependent manner. Population and genetic attributes should reflect this basic dichotomy in the conditions of seedling recruitment. I predict that seedlings of scatter-dispersed species rarely survive near parents or in dense aggregations under frugivore roosts. Seed dispersal should be mandatory, often to light gaps or other special habitats. Outbred adults and juveniles are expected to exist at low densities in loose aggregations or random distributions. Seedlings of clump-dispersed trees are pre-adapted for survival in dense aggregations near parents, as well as in fecal clumps. Substantial recruitment of juveniles and young adults should occur from undispersed seeds under and near parent trees. Such species should be common, highly aggregated, and show strong genetic family structure. Because recruitment requires dispersal, scatter-dispersed plant species should be especially vulnerable to loss of dispersal agents. Because offspring consistently recruit near parents, clump-dispersed plants should be less vulnerable to temporary loss of dispersal agents.
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  • 72
    ISSN: 1432-1939
    Keywords: Phacophyta ; Inorganic carbon assimilation ; Carbonic anhydrase ; Carbon dioxide compensation concentration ; Ecology ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Characteristics of inorganic carbon assimilation by photosynthesis in seawater were investigated in six species of the Fucales (five Fucaceae, one Cystoseiraceae) and four species of the Laminariales (three Laminariaceae, one Alariaceae) from Arbroath, Scotland. All of the algae tested could photosynthesise faster at high external pH values than the uncatalysed conversion of HCO 3 - to CO2 can occur, i.e. can “use” external HCO 3 - . They all had detectable extracellular carbonic anhydrase activity, suggesting that HCO 3 - use could involve catalysis of external CO2 production, a view supported to some extent by experiments with an inhibitor of carbonic anhydrase. All of the algae tested had CO2 compensation concentrations at pH 8 which were lower than would be expected from diffusive entry of CO2 supplying RUBISCO as the initial carboxylase, consistent with the operation of energized entry of HCO 3 - and / or CO2 acting as a “CO2 concentrating mechanism”. Quantitative differences among the algae examined were noted with respect to characteristics of inorganic C assimilation. The most obvious distinction was between the eulittoral Fucaceae, which are emersed for part of, or most of, the tidal cycle, and the other three families (Cystoseiraceae, Laminariaceae, Alariaceae) whose representatives are essentially continually submersed. The Fucaceae examined are able to photosynthesise at high pH values, and have lower CO2 compensation concentrations, and lower K1/2 values for inorganic C use in photosynthesis, at pH 8, than the other algae tested. Furthermore, the Fucaceae are essentially saturated with inorganic C for photosynthesis at the normal seawater concentration at pH 8 and 10°C. These characteristics are consistent with the dominant role of a “CO2 concentrating mechanism” in CO2 acquisition by these plants. Other species tested have characteristcs which suggest a less effective HCO 3 - use and “CO2 concentrating mechanism”, with the Laminariaceae being the least effective; unlike the Fucaceae, photosynthesis by these algae is not saturated with inorganic C in normal seawater. Taxonomic and ecological implications of these results are considered in relation to related data in the literature.
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  • 73
    ISSN: 1432-1939
    Keywords: Logging disturbance ; Land gastropods ; Ecology ; Genetics ; Population
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ecological and genetic properties of two North American terrestrial gastropods (Mesomphix spp.) were characterized in paired control and previously logged watersheds in two North Carolina forests (Coweeta and the Great Smoky Mountains National Park) of the Southern Appalachian Biosphere Reserve Cluster. Shell growth was greater in the control sites, but density and mortality were largely independent of prior logging history and forest reserve. Based on starch gel electrophoresis data, both species showed their highest levels of genetic diversity in the Coweeta forest, the component of the reserve cluster which had the most extensive and variable history of logging disturbance. M. subplanus also exhibited higher levels of heterozygosity in logged than in control watersheds, and M. andrewsae showed over twice as many rare alleles in disturbed sites as in control sites. F-statistic analysis depicted both excess levels of homozygosity and moderate genetic differentiation among the populations, reflecting the effects of small population size and perhaps drift and inbreeding. Estimated gene flow was relatively low. These results correspond to the recent finding by Bryant et al. (1987) and others on the effects of bottlenecks, and to the contrasting history of habitat instability of the two major study forests.
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  • 74
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    Environmental management 13 (1989), S. 43-54 
    ISSN: 1432-1009
    Keywords: Sustainable development ; Ecology ; Agroecosystems ; Field research ; Statistical reliability ; Southeast Asia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Farmers attempting to subsist in tropical uplands often rely upon unsustainable resource use practices that lead to soil erosion, declining crop yields, and a loss of soil productivity capacity. Other uses of tropical uplands, including logging and conversion of forest to rangelands, have similar results. The undesirable effects of these actions are felt on-site, at the watershed level, and even nationally. Ecological cause-effect relationships are poorly understood, and few examples exist of the successful integration of ecological knowledge with upland development. It is hypothesized that recent results of ecological research could be applied to uplands management so that stable sustainable systems of human use may be established. A second hypothesis is that statistically reliable data can be obtained from experiments in upland situations, although natural variations of soils, weather, and vegetation are great. To test these hypotheses, research involving multinational collaboration among American and Southeast Asian scientists has begun. The objective of the work is to provide credible quantitative information to help policy and decision makers and resident farmers to plan and implement improved practices based on ecological principles. Some findings to date include: 1. Ecological principles are difficult to relate to the practical context of upland agroecosystems. Indeed, the null hypothesis is necessary for planning experiments and demonstrations. 2. The “signal-to-noise” ratio in these field experiments is low, and the detection of changes due to human intervention in soil erosion, nutrient movement, and plant productivity is difficult. 3. Obstacles to field research in developing countries include logistic, cultural, political, and institutional factors. It is essential that local land managers participate from the start with scientific researchers in designing experiments. 4. Planned collaboration among academic and government scientists facilitates design of relevant research and the implementation of results. 5. The idea of ecologically based management has been well received by researchers and government officials in Asia. There is little argument with the logic of the approach. 6. Pressures for quick responses to urgent problems in the uplands conflict with the need for careful, long-term, statistically valid scientific research. 7. Ecological principles are vaguely understood and poorly articulated in the scientific literature. The transfer and application of ecological science to the developing world would be enhanced by clearer statements of principles.
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    Environmental management 13 (1989), S. 425-433 
    ISSN: 1432-1009
    Keywords: Interdisciplinarity ; Small islands ; Aeolian project ; Ecology ; Economy ; Human factors ; Environmental research methodology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Environmental research is characterized in each of its successive phases by a strong interdisciplinarity. A rotational groups system (RGS) method is proposed as an instrument to encourage interaction among researchers from fields that are traditionally far apart. Meetings conducted with the RGS procedure involve all the researchers, who, in repeated and topical encounters, are able to exchange information on a wide variety of environmental subjects. These meetings can be arranged according to a special calendar, through a series of phases treating different aspects of the same subjects to be discussed, and above all, referring to specific “themes” and “working guidelines” organized on the basis of criteria designed to favor an exchange of ideas and constructive discussion. At the end, the plenary assembly edits an overall resume of the proceedings, and votes on the final resolution, which brings together all the conclusive opinions regarding the themes discussed.
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    Environmental biology of fishes 25 (1989), S. 187-193 
    ISSN: 1573-5133
    Keywords: Foraging ; Ethology ; Ecology ; Chaetodontid ; Territorial ; Corallivore ; Corals ; Reef
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The chevron butterflyfish,Chaetodon trifascialis, is found throughout the Indo-Pacific. It is a territorial, diurnal, corallivore found in close association withAcropora spp. corals. The feeding behavior of 33 individuals was studied over six seasons in three habitats.Chaetodon trifascialis spent one third of its active time feeding. However, there was much individual variation. Fish had significantly higher feeding rates during the early afternoon, and there were no significant differences in the feeding rates between the seasons. Feeding rates were significantly different between the three habitats. TheMontipora-rich habitat had the highest feeding rates (x = 10.74 bites min-1 ± 0.87, all corals combined) and theAcropora-Montipora mixed habitat had the lowest feeding rates (x = 4.58 bites min-1 ± 0.63, all corals combined). Females fed significantly more than males. WhileC. trifascialis had been thought to only eatAcropora spp. corals, it occasionally fed onMontipora spp. andPocillopora sp. corals whenAcropora spp. were scarce.Chaetodon trifascialis exhibited patterns predicted by foraging theory of an energy maximizer. Territory sizes were inversely related to food density and feeding rates were inversely related to intruder rates. This is a promising system for future testing of foraging strategy models.
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    Human evolution 4 (1989), S. 105-116 
    ISSN: 1824-310X
    Keywords: Ecology ; locomotion ; heterochrony ; recognition concept
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Patterson's Recognition Concept of Species has profound implications for the way we analyze the process of species formation. It emphasizes absolute rather than relativistic mechanisms, and concentrates on adaptive processes within population isolates rather than competitive exclusion or competition. Environmental change is seen as a major force initiating speciation. In the case of two species ofGalago, environmental degradation and the breakup of forest blocks is likely to have been the major initiator; while changes in sea-level may have lead to the fragmentation of populations ofTarsius. In both cases, however, the relationships of body size, energetics, heterochrony and species strategies most likely provided the engine for further behavioural and morphological divergence.
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    Journal of industrial microbiology and biotechnology 3 (1988), S. 179-194 
    ISSN: 1476-5535
    Keywords: Aquifer ; Biodegradation, anaerobic ; Pollutant ; Groundwater ; Methanogenesis ; Sulfate-reduction ; Ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Anaerobic microbial communities sampled from either a methanogenic or sulfate-reducing aquifer site have been tested for their ability to degrade a variety of groundwater pollutants, including halogenated aromatic compounds, simple alkyl phenols and tetrachloroethylene. The haloaromatic chemicals were biodegraded in methanogenic incubations but not under sulfate-reducing conditions. The primary degradative event was typically the reductive removal of the aryl halides. Complete dehalogenation of the aromatic moiety was required before substrate mineralization was observed. The lack of dehalogenation activity in sulfatereducing incubations was due, at least in part, to the high levels of sulfate rather than a lack of metabolic potential. In contrast, the degradation of cresol isomers occurred in both types of incubations but proved faster under sulfate-reducing conditions. The requisite microorganisms were enriched and the degradation pathway forp-cresol under the latter conditions involved the anaerobic oxidation of the aryl methyl group. Tetrachloroethylene was also degraded by reductive dehalogenation but under both incubation conditions. The initial conversion of this substrate to trichloroethylene was generally faster under methanogenic conditions. However, the transformation pathway slowed when dichloroethylene was produced and only trace concentrations of vinyl chloride were detected. These results illustrate that pollutant compounds can be biodegraded under anoxic conditions and a knowledge of the predominant ecological conditions is essential for accurate predictions of the transport and fate of such materials in aquifers.
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    Primates 29 (1988), S. 135-137 
    ISSN: 0032-8332
    Keywords: Papio ; Body size ; Ecology ; Climate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Popp (1983) presented an intriguing argument regarding the covariation of body size in baboons and rainfall. However, a reanalysis of the data indicates that “Principle 2” of the model is not supported.
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    Environmental biology of fishes 23 (1988), S. 141-154 
    ISSN: 1573-5133
    Keywords: Cyanide ; Diversity ; Development ; Ecology ; Environment ; Fisheries ; Pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The biological diversity and productivity of Philippine coral reefs are threatened by siltation, destructive fishing methods, coral and shell collecting and overfishing. Destructive fishing includes: the widespread, illegal use of explosives; poisons such as sodium cyanide; muro-ami and kayakas fishing; and trawling. The recent decline in catch rates threatens the livelihood of 700 000 near-shore subsistence fishermen who catch 55% of the total landings. The new government under Corazon Aquino wishes to protect the marine environment through the creation of a viable marine conservation management plan, enforcement of existing laws and through cooperation between government, non-government and international agencies to provide education and research. The Department of Agriculture, which has the authority for fisheries, has designated the International Marinelife Alliance as the lead non-government agency involved with fund raising, net-training and finding alternatives to destructive fishing methods.
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  • 81
    ISSN: 0032-8332
    Keywords: Ecology ; Diet ; Sympatry ; Competition ; Polyspecific groups
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ecologies of two sympatric primates,Saguinus fuscicollis andCallicebus moloch, were compared during a four-month field study in southeastern Peru in order to examine the mechanisms by which these primate frugivores minimize competition for food and space.Saguinus fuscicollis andCallicebus moloch were found to differ dramatically both in diet and in use of the shared habitat. Specifically, tamarins and titis showed very little overlap in their choices of food plants or animal foods and they used distinctive foraging styles, exploiting very different parts of the habitat for animal prey. Significant interspecific differences were found in the use of particular support structures and strata within the forest, and in the density of vegetation preferred. These results suggest that resource competition between saddle-backed tamarins and dusky titis is minimal, a fact that could account for the high frequency of free association between the two species and the benign nature of these interspecific contacts.
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  • 82
    ISSN: 1432-1009
    Keywords: Flushing ; Scouring ; Channel Maintenance ; Fisheries ; Trinity River
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The operation of Trinity and Lewiston Dams on the Trinity River in northern California in the United States, combined with severe watershed erosion, has jeopardized the existence of prime salmonid fisheries. Extreme streamflow depletion and stream sedimentation below Lewiston have resulted in heavy accumulation of coarse sediment on riffle gravel and filling of streambed pools, causing the destruction of spawning, nursery, and overwintering habitat for prized chinook salmon (Salmo gairdnerii) and steelhead trout (Oncorhynchus tschawytscha). Proposals to restore and maintain the degraded habitat include controlled one-time remedial peak flows or annual maintenance peak flows designed to flush the spawning gravel and scour the banks, deltas, and pools. The criteria for effective channel restoration or maintenance by streambed flushing and scouring are examined here, as well as the mechanics involved. The liabilities of releasing mammoth scouring-flushing flows approximating the magnitude that preceded reservoir construction make this option unviable. The resulting damage to fish habitat established under the postproject streamflow regime, as well as damage to human settlements in the floodplain, would be unacceptable, as would the opportunity costs to hydroelectric and irrigation water users. The technical feasibility of annual maintenance flushing flows depends upon associated mechanical and structural measures, particularly instream maintenance dredging of deep pools and construction of a sediment control dam on a tributary where watershed erosion is extreme. The cost effectiveness of a sediment dam with a limited useful economic life, combined with perpetual maintenance dredging, is questionable.
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    Primates 28 (1987), S. 473-496 
    ISSN: 0032-8332
    Keywords: Chimpanzee ; Pan troglodytes ; Tool use ; Biogeography ; Ecology ; Ethology ; Food
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two types of use of “hammers” for cracking nuts by wild-living chimpanzees have been distinguished: (1) Relatively small stones are used by the chimpanzee community at Bossou in Guinea to crack the nuts of oil palms growing on abandoned farmland, while no nuts of wild tree species are cracked. (2) Larger hammer stones (and, at some sites, wooden clubs) are used in a more sophisticated manner to crack the nuts of wild trees, but not of oil palms, in an area ranging from south-east Sierra Leone through Liberia to the south-west of the Ivory Coast. The first author (1986) has proposed that Type I has been copied by the chimpanzees, under pressure of food shortage, from the local human population. New data now indicate that, at Bossou, while habitat deterioration has continued, the number of hammer and anvil stones per utilized oil palm tree has approximately tripled in the last six years. The quantity of food obtained from oil palm nut kernels, however, amounts to only a few percent of the total diet. For the rest these apes depend to a large extent on many other agricultural products cultivated at Bossou which they are allowed freely to consume, including even cassava (manioc) roots and sweet potatoes dug by them from the ground. Some factors determining the chosen size of hammers were analyzed. Two abnormal hammers were found whose wear suggested a tentative, human-like manner of use. No evidence has been found to indicate the use of stone tools by chimpanzees in the adjoining chimpanzee-inhabited areas around the range of the Bossou community. Type II stone tool use was found, however, in a primary forest on a mountain≈13 km west of Bossou. This is especially intriguing because the site is separated by a wide belt of drier rain forest from the belt of very humid rain forest in the south where all the other known Type II sites are located. More research on the geographical distribution of the use of stone tools by chimpanzees and on the underlying ecological factors is recommended.
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  • 84
    ISSN: 1573-5133
    Keywords: Chondrichthyes ; Elasmobranchs ; Fisheries ; Ageing methods ; Growth rates ; Gestation periods ; Maturity ; Vertebral bands ; Weight-length relationships ; Life histories
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The silky shark, Carcharhinus falciformis, and scalloped hammerhead, Sphyrna lewini, represent 〉80% of the shark by-catch of the winter swordfish/tuna longline fishery of the northwestern Gulf of Mexico. This catch represents a potential supplemental fishery, yet little is known of the life histories of the two species. This report relates reproductive biology data to age and growth estimates for 135 C. falciformis and 78 S. lewini. Unlike other regional populations, C. falciformis in the Gulf of Mexico may have a seasonal 12 month gestation period. Males mature at 210–220 cm TL (6–7 yr); females at 〉225 cm TL (7–9 yr). Application of age at length data for combined sexes produced von Bertalanffy growth model parameter estimates of L∞ = 291 cm TL, K = 0.153, t0 = −2.2 yr. Adult male S. lewini outnumbered adult females in catches because of differences in the distributions of the sexually segregated population. Males mature at 180 cm TL (10 yr); females at 250 cm TL (15 yr). von Bertalanffy parameter estimates for combined sexes of this species were L∞ = 329 cm TL, K = 0.073, to = −2.2 yr.
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  • 85
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    Environmental biology of fishes 19 (1987), S. 297-308 
    ISSN: 1573-5133
    Keywords: Ecology ; Fish ; Leiognathids ; Mangroves ; Nekton ; Papua New Guinea ; Periodicity ; Prawns ; Tidal cycles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Using a 3 m beam trawl, catch variation in the fish and prawn assemblage of the Labu estuary, Papua New Guinea was investigated during July and December 1981 and September 1984. About six times more organisms, three and a half times the biomass and twice as many species were caught per trawl at night than during the day. The greatest number of species, individuals and biomass were caught just after dusk. With the exception ofSecutor ruconius, there was no significant difference in the catches trawled at ebbing and flooding tides. Over twice as many individuals ofS. ruconius were caught during ebbing tides. Alignment of trawl direction in relation to the tidal current did not have a significant effect on the fish catch, but affected the prawn (Metapenaeus demani) catch. It is postulated that most species are not carried to and fro by tidal currents, but maintain their position in the estuary with respect to the substratum. Only prawns appeared to be carried by the currents. This study indicates that the most representative trawl results in terms of species diversity and abundance in shallow estuaries may be obtained at night and, that in estuaries with a small tidal range, tidal direction and velocity have little influence on catch. It also indicates that analyses of demersal nekton assemblages from daytime only estuarine trawl surveys must be approached with caution.
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  • 86
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    Environmental biology of fishes 20 (1987), S. 293-300 
    ISSN: 1573-5133
    Keywords: Osmeridae ; Barents Sea ; Ecology ; Temperature ; Length growth ; Otoliths
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis In order to investigate a possible relationship between temperature and fish length growth in the Barents Sea capelin stock, estimates of environmental temperature in the feeding season were compared to estimates of length growth during the same season. The mean temperature of the capelin feeding area was calculated by averaging the temperatures in September for the depth interval 10–200 m in statistical rectangles. The estimates of capelin growth were obtained for the same rectangles using backcalculation of length from otoliths. Correlation coefficients for the relationship between water temperature and growth were 0.70 and 0.53 for two- and three-year-olds, respectively, when all the material was considered, and between 0.85 and 0.91 for within-year data. In addition, a close correspondence between feeding area and growth rates was found.
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  • 87
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    Journal of mathematical biology 24 (1986), S. 479-523 
    ISSN: 1432-1416
    Keywords: Nonlinear dynamics ; Noise ; Chaos ; Ecology
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    Topics: Biology , Mathematics
    Notes: Abstract We investigate effects of random perturbations on the dynamics of one-dimensional maps (single species difference equations) and of finite dimensional flows (differential equations for n species). In particular, we study the effects of noise on the invariant measure, on the “correlation” dimension of the attractor, and on the possibility of detecting the nonlinear deterministic component by applying reconstruction techniques to the time series of population abundances. We conclude that adding noise to maps with a stable fixed-point obscures the underlying determinism. This turns out not to be the case for systems exhibiting complex periodic or chaotic motion, whose essential properties are more robust. In some cases, adding noise reveals deterministic structure which otherwise could not be observed. Simulations suggest that similar results hold for flows whose attractor is almost two-dimensional.
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  • 88
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    Protoplasma 135 (1986), S. 162-165 
    ISSN: 1615-6102
    Keywords: Alga ; Chlorella ; Ecology ; Virus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A tail-less polygonal virus with a prominent capsid of about 140–150 nm in diameter and about 14–15 nm in thickness has been isolated from a freshwater pond. It shows a marked host specificity in attacking only an endosymbioticChlorella sp. isolated fromParamecium bursaria (Ciliata). Viral replication starts in the algal cytoplasm and both autospores and old cells are lysed. The ecology of the virus in the freshwater habitat is discussed. Screening tests for further phycoviruses were not successful.
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  • 89
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    Primates 27 (1986), S. 337-355 
    ISSN: 0032-8332
    Keywords: Prosimians ; Tarsius bancanus ; Locomotion ; Ecology
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    Topics: Biology
    Notes: Abstract Four adultTarsius bancanus were followed for a total of over 120 hrs in Sepilok Forest Reserve, Sabah, using radiotracking techniques. Seven hundred and twenty-two records of locomotor and postural behaviour were gathered.Tarsius bancanus travels a mean of 1,800 m per night, over large (4.5 to 11.25 ha) ranges. They move at a mean height of 0.89 m, utilizing primarily vertical sapling trunks of diametre 2 to 4 cm. Lateral movement is carried out largely by leaping.Tarsius were found on the ground in 5.3% of cases, but movement on the ground is very largely restricted to short investigative movements by walking. Climbing is mostly related to foraging behaviour and characteristically occurs on relatively small supports.Tarsius bancanus' locomotion is similar to, but more specialized than that ofT. spectrum, Galago alleni, andGalago senegalensis, all of which have rather similar patterns of habitat utilization. We suggest that the energetic constraints of small body size together with the need to patrol large home ranges may have lead both toTarsius bancanus extreme degree of locomotor specialization and to its exclusive animalivory.
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  • 90
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    Primates 27 (1986), S. 151-172 
    ISSN: 0032-8332
    Keywords: Presbytis thomasi ; Ecology ; Behavior ; Social change ; Killing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A field study of 23 bisexual troops, ranging in size from 3 to 21 members ( $$\bar x$$ =8), and two all-male groups of the Thomas's leaf monkey (Presbytis thomasi) was conducted in North Sumatra from November 1981 to April 1984. Most troops (N=19 or 82.6%) contained only one adult male. Two troops and one group were most intensively studied. The home range was 12.3–15.7 ha for the two bisexual troops, and only 1.7 ha for the one, all-male, ten-member group. Fruits composed more than 50% of their diets. Vocalizations were classified into 13 types. Births occurred at any time of the year. Among three males of a bisexual troop, serious fights were observed: two males died of wounds and the former beta male became the new alpha male. After this social change, the home range area of this troop gradually shifted eastward. But, 3.5 months after the social change, a 9-month-old infant male stayed alone in the western part of its former range. Thereafter, he became a solitary male and sometimes went into the riverine area of the Bohorok river. The occurrence of male replacement suggests instability of multi-male organization in bisexual troops. Moreover, the different mortality rate between males and females and the unequal sex ratios forced by the formation of one-male troops, maintained high tension levels among males competing on females.
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  • 91
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    Hydrobiologia 132 (1986), S. 295-303 
    ISSN: 1573-5117
    Keywords: Turbellaria ; Meiofauna ; Ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recent data and opinions on meiofaunal ecology are briefly reviewed; and from scattered data, the place of turbellarians in the meiobenthic community is discussed. Turbellarian diversity, density, and biomass are higher in sandy habitats than in muddy bottoms. In sand, turbellarian diversity is of the same magnitude as that of other important meiofaunal taxa, while densities range between 7–25% of the total meiofauna. Mean individual turbellarian dry weight seems to be four times that of nematodes and in sandy habitats turbellarian biomass may be equal to or excede that of nematodes. Most turbellarian species may be considered as predators and in this respect may take the place occupied by macrofaunal species in muddy sediments. mens.
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  • 92
    ISSN: 1573-5133
    Keywords: Fish epigenesis ; Ecology ; Evolution ; Embryonic arrest ; Hatching initiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Developmental patterns as seen in cyprinodontiforms fishes with different reproductive styles are compared, and discussed in relation to ecology and evolutionary significance. The discussion centres around Adinia xenica (its detailed ontogeny presented in two previous sequels to this paper), and, from the existing literature, Fundulus heteroclitus (closely related), Austrofundulus myersi (an annual) and Platypoecilus maculatus (a livebearer). The embryonic resting interval is present in various forms in the first three species, and differences in it and the overall patterns of development are shown to be consistent with ecological conditions. Termination of the resting interval leads immediately to hatching, a process in A. xenica, as in F. heteroclitus, apparently initiated by the appropriate summation of internal and external factors. These factors include any or all of: metabolic changes and increased oxygen requirements, response to light, reduced environmental oxygen, agitation, and increased hydrostatic pressure. They all can cause increased movement by the embryo which is credited with rupturing hatching gland cells and releasing the enzyme(s). Annual fishes experience 3 pronounced resting intervals, termed diapauses. These are discussed in the context of apparent steps and thresholds, and evolutionary ecology. A possible evolutionary sequence, from a simple fractional spawning pattern to diapause, is presented. Morphological differences in primary embryonic respiratory surfaces, as seen in the four species, are related to environmental conditions. The above illustrate ways in which the same basic structures and events are modified to cope with different habitats.
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  • 93
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    Environmental biology of fishes 17 (1986), S. 23-40 
    ISSN: 1573-5133
    Keywords: Cottids ; Ecology ; Littoral ; Marine ; Pacific ; Sculpins ; Tidepools ; Zoogeography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis We examined data from our own and published collections of intertidal and shallow littoral fishes of the North American Pacific Coast with respect to temporal and spatial trends in species composition and dominance. We compared (1) recent and past intertidal collections made five and seven years apart, respectively, for two California localities, (2) intertidal collections from twelve localities in California, Oregon, and British Columbia, and (3) intertidal versus subtidal collections at one California locality. Temporal comparisons indicated substantially lower abundance of the cottid Oligocottus snyderi at two California localities during 1984, at one locality due to depressed abundance of young. Interannual differences in abundances suggested that other tidepool fish assemblages undergo significant changes as well. Geographical comparisons indicated general similarity in species composition, with cottids predominating in tidepools although several other families also were well represented (e.g., Stichaeidae, Scorpaenidae). Eel-shaped stichaeids and pholids occurred at high densities in exposed boulder fields. Both the tidepool and boulder field assemblages showed north-south changes in species abundances. Comparison of collections from the intertidal and subtidal zones at one California locality demonstrated that fishes of these habitats form two essentially distinct assemblages, with most species restricted to or concentrated in one or the other habitat.
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  • 94
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    Plant and soil 90 (1986), S. 117-128 
    ISSN: 1573-5036
    Keywords: Azospirillum ; Bacteriophage ; Chernozemic soil ; Ecology ; Latosol soil ; Podzolic soil ; Population dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary This study examined the ecology and interaction ofAzospirillum brasilense and its bacteriophage in soil. Four Chernozemic soils from Canada, a Latosol and three Podzolic soils from Brazil were assayed for phage. Only the Latosol containedA. brasilense phage. None of the soils contained phage for otherA. brasilense orA. lipoferum strains tested. Recovery of phage from soil depended on the growth of indigenous or added host cells. A phage isolated from the Latosol had a hexagonal head of 100 nm and a tail of 200 nm. This phage was morphologically distinct from previously described Azospirillum phage and its host range was limited toA. brasilense strains 29145 and 29711. Survival and recovery of phage added to phage-free soil was dependent on the phage, the initial phage population, the presence of host cells and nutrients, and the soil. Phage persisted in soils at undetectable levels for at least seven weeks, but were still able to interact with multiplying host cells and exhibit a 1000-fold increase in number. Phage required a host cell population of at least 100–1000 per g of soil in order to multiply. The phage burst detected under these conditions increased as the cell to phage ratio increased. Long term incubation studies showed that the activity of phage in soil closely followed the activity of host cells and thus both were manipulated by appropriate amendments to soil.
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  • 95
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    Plant and soil 92 (1986), S. 249-254 
    ISSN: 1573-5036
    Keywords: Ecology ; Nitrogen fixation ; Rhizobium leguminosarum populations ; Vicia faba
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The size and symbiotic effectiveness, withVicia faba, ofRhizobium leguminosarum populations from five locations in southern Britain has been estimated. Population numbers varied from 4.54×103 to 1.69×105. Nitrogen fixing potential differed by up to 30%. The implications of the results for improving the productivity of field beans are discussed.
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  • 96
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    Plant and soil 95 (1986), S. 285-288 
    ISSN: 1573-5036
    Keywords: Ecology ; Germination ; Seeds ; Soil-water potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Seeds were germinated in soils of known matric potential (ψm) achieved by adding the requisite amount of water to air-dry soil and mixing for several days. The quantity of water was derived from calibration curves of water content against ψm by use of pressureplate extraction equipment. Soils were transferred to plastic Petri dishes in which seeds were sown. Variations of the technique permitted germination counting through the transparent dish lid, or by opening the dish and either resealing or discarding the replicate dish. Measurements of ethylene and carbon dioxide in the soil atmosphere suggest that neither gas accumulated to a level which could interfere with interpretation of results. Some species showed sensitivity of germination to water potential which was correlated with the relative wetness of their habitats.
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  • 97
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    Plant ecology 62 (1985), S. 319-326 
    ISSN: 1573-5052
    Keywords: Atriplex ; Cakile ; Ecology ; Salsola ; Strandline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Factors which affect the vegetation of strandlines on sandy shores were investigated with particular attention to the growth of four annual species Atriplex glabriuscula, Atriplex laciniata, Cakile maritima and Salsola kali which are widely distributed around the coasts of North-West Europe. The response of these species to increases in salinity and sand accretion are reported from laboratory experiments. Field observations were also made of photosynthesis and the availability of, and the response to, nitrogen. The results are used to discuss the adaptation of these plants to growth on strandlines in an attempt to explain their restriction to this habitat.
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  • 98
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    Environmental biology of fishes 13 (1985), S. 173-181 
    ISSN: 1573-5133
    Keywords: Evolution ; Ecology ; Morphometrics ; Morphology ; Electroreception ; Orinoco River ; Venezuela
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Examination of 681 individuals of electric knife-fishes, Eigenmannia macrops, from the Orinoco River, Venezuela, revealed a pattern of morphological diversity which covaried with habitat. Fishes from the caños (small stream tributaries) are on average smaller than those from offshore habitats and lagoons. Even at the same body size the tails of caño fishes are relatively shorter, their bodies are deeper, and their heads are relatively wider than those from other habitats. Caño fishes are more different from fishes of the deep channels than from those of the shallow channels, beaches, or lagoons. Several factors are examined for their possible relationship to the origin of the observed diversity including electrophysiology, locomotory adaptation, growth rate and ecology. The problems of genetic versus physiological bases of morphological variation are addressed.
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  • 99
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    Environmental biology of fishes 13 (1985), S. 211-224 
    ISSN: 1573-5133
    Keywords: Competition ; Food resources ; Habitat ; Ontogeny ; Ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Patterns of food use and food availability were analysed in a species rich summer weedbed community of juvenile lake fish to elucidate ontogenetic and ecological adaptations facilitating species co-existence and rapid growth. It was found that: (a) the community was based on the period of high seasonal invertebrate abundance linked to the spring-summer proliferation of macrophytes: food was not limiting; (b) diet separations of individual fish species were high. In mid-July when nine species were present, Schoener diet overlap values exceeded 0.25 in only ten of 36 pairs of combinations. This contrasted with findings from a preceding May-June community of larval fish (Keast 1980); (c) mouth size helped channel the species towards different diets; and (d) diets of the early juveniles were distinct from those of the larvae, and late juveniles and adults of their species. At both the species and community level, ontogenetic and ecological developments have evolved in response to the opportunities created by an annually repetitive resource base.
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  • 100
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    Environmental biology of fishes 14 (1985), S. 61-72 
    ISSN: 1573-5133
    Keywords: Acipenseridae ; Life history ; Ecology ; Harvest ; Culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The Atlantic sturgeon supported major fisheries along the entire Atlantic coast of North America. These fisheries peaked about 1890 and then suffered almost total collapse by 1905. The Atlantic sturgeon is anadromous and highly susceptible to capture during spawning migrations. Further, this species biological characteristics makes it very vulnerable to man-induced changes in natural habitat and slow to recover. Atlantic sturgeon mature at an advanced age (7–27 year for females, depending on latitude), exhibit a long interspawning period (2–5 year), and require suitable riverine, estuarine, and coastal environments for successful completion of their life cycle. Today, only remnant stocks exist in areas of former abundance. Management regulations vary considerably from state to state and range from full protection to no protection. Biological data are needed to: identify and characterize specific spawning and nursery areas; delineate migratory patterns and recruitment to various stocks; establish stock abundance; and, assess effects of various management strategies. In order to protect remaining stocks, the imposition of a total harvesting moratorium is recommended.
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