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  • 1
    Electronic Resource
    Electronic Resource
    Biodiversity Resources for Restoration Ecology (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Restoration ecology 2 (1994), S. 0 
    Details
    ISSN: 1526-100X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Biological resources can be more usefully incorporated into many aspects of restoration ecology. During the planning and design stage, the wide genotypic variation in natural plant populations must be recognized and exploited. This will ensure that genotypes used on a site are best adapted to local conditions and have a greater probability of survivorship than arbitrarily chosen material. Also, certain unusual genotypes can be located using the principles of evolutionary ecology and can be installed in areas with extreme conditions, such as soils contaminated with heavy metals, in areas where rapid colonizing ability (high seed set and/or clonal growth) is particularly advantageous, or where soils are of poor quality. Similarly, where high herbivore pressure is a threat to restoration, genotypes that are well defended, chemically or mechanically, against animal enemies should be selected to initiate the restoration process. The nursery industry can be encouraged to supply an ecologically wider selection of material for restoration, originating from local biological reserves and natural habitats. During the management phase of a restoration, local natural habitats are critical as reservoirs of biological control agents, seed sources for plant species, and members of higher trophic levels and additional plant species needed during succession. Mutualists such as pollinators, seed dispersers, and mycorrhizal fungi are vital to the success of a restoration project, and these must invade from nearby natural habitats or must be deliberately introduced. During the evaluation phase of restoration, local natural areas should be used as templates of community composition and structure from which one measures success. A functioning restoration project will interact biologically with surrounding areas, the exchange of species and genes being particularly important. Analysis of the microbial and invertebrate communities that have invaded the installed plant community may be useful and accurate determinants of ecological function. For these latter stages of the restoration process, the value of preserving local habitat remnants is high and complements their usefulness as a source of ecologically precise material for installation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1526-100X.1994.tb00055.x
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  • 2
    Electronic Resource
    Electronic Resource
    Impacts of grazing and burning on spider assemblages in dry eucalypt forests of north-eastern New South Wales, Australia (2003)
    Oxford, UK : Blackwell Science Pty
    Austral ecology 28 (2003), S. 0 
    Details
    ISSN: 1442-9993
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract In the dry eucalypt forests of north-eastern New South Wales, Australia, cattle grazing occurs at low intensities and is accompanied by frequent low-intensity burning. This study investigated the combined effects of this management practice on the ground-dwelling and arboreal (low vegetation) spider assemblages. Spiders were sampled at 49 sites representing a range of grazing intensities, using pitfall trapping, litter extraction and sweep sampling. A total of 237 spider morphospecies from 37 families were collected using this composite sampling strategy. The abundance, richness, composition and structure of spider assemblages in grazed and ungrazed forest sites were compared and related to a range of environmental variables. Spider assemblages responded to a range of environmental factors at the landscape, habitat and microhabitat scales. Forest type, spatial relationships and habitat variability at the site scale were more important in determining spider assemblages than localized low-intensity grazing and burning. However, it is possible that a threshold intensity of grazing may exist, above which spiders respond to grazing and burning. Although low-intensity grazing and burning may not affect spider assemblages below a threshold stocking rate, that stocking rate has yet to be established.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1442-9993.2003.01310.x
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  • 3
    Electronic Resource
    Electronic Resource
    Patterns of invertebrate biodiversity across a natural edge (2003)
    Oxford, UK : Blackwell Science Pty
    Austral ecology 28 (2003), S. 0 
    Details
    ISSN: 1442-9993
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Most ecologists are comfortable with the notion of habitats as recognizable entities and also with situations where the junction between two adjacent habitats forms a discrete edge. Such edges form naturally because of sharp changes in important edaphic, geomorphological, climatic or chemical properties to which plants, in particular, respond. Less clear is the effect of such edges on assemblages of mobile organisms, especially invertebrates that operate at relatively small spatial scales. The objective of the present study was to sample invertebrate composition across a natural edge between a well-developed riparian habitat on fluvial sands and a saltbush habitat developed on a stony gibber plain in a semi-arid region of New South Wales, Australia. A total of 150 pitfall traps on five 1-km-long transects that straddled the edge produced more than 13 000 adult specimens from 21 ordinal invertebrate taxa. A total of 10 446 beetle, ant, wasp, fly and springtail specimens were further sorted into 426 morphospecies. Comparisons and estimates of trends in abundance and richness were made, along with computation of multivariate dissimilarity and permutation statistics, to determine if the land system edge was coincident with changes in invertebrate abundance and composition. These analyses were unable to detect disjunctions in diversity coincident with the edge. The data suggest that many taxa are either present consistently in both habitats or are mostly found in one habitat but ‘leak’ several hundred metres across into the other. Few taxa were unique to either habitat. The result is that assemblage composition for invertebrates changes gradually over distances of up to 400 m either side of the edge and that the distance to a recognizable change in composition is taxon dependent. Even sharp habitat edges, as defined by discrete changes in soils and plants, are not edges but broad transition zones for many invertebrate taxa. There are several implications of these results, especially for landscape ecology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1442-9993.2003.01240.x
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  • 4
    Electronic Resource
    Electronic Resource
    Contribution of oribatid and mesostigmatid soil mites in ecologically based estimates of global species richness (2001)
    Melbourne, Australia : Blackwell Science Pty
    Austral ecology 26 (2001), S. 0 
    Details
    ISSN: 1442-9993
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Erwin’s method for estimating total global species richness assumes some host-specificity among the canopy arthropods. This study examined possible host habitat specialization in two major groups of soil arthropods, the oribatid and mesostigmatid mites, by sampling beneath three tree species: Eucalyptus pilularis Smith, Eucalyptus propinqua Deane and Maiden and Allocasuarina torulosa (Aiton) L. Johnson. The sample sites were in the Lansdowne State Forest, New South Wales, Australia and the three tree species were selected on the basis of their known differential effects on soil. Sampling was conducted over three seasons, and 79 oribatid and 34 mesostigmatid species were identified from 25 196 and 3634 individuals, respectively. Tree species had little effect on mite species composition with only three oribatid species and no mesostigmatid species identified as host-habitat specialists using a niche breadth measure. Of mite species found under E. pilularis, E. propinqua and A. torulosa trees, 2%, 1% and 0% were defined as host-habitat specialists, respectively. In contrast, tree species had significant and consistent effects on mite community structure, which differed in relative abundance of the oribatid species, their size class distributions and species rankings. In the mesostigmatid communities, there was a difference in the ranking of the mite species among tree species. Although it was demonstrated that tree species have an impact on the soil environment, the differences between tree species were insufficient to change species composition. The low degree of host-habitat specialization suggested that other factors were more important for determining mite species composition at a site, and soil mite host-habitat specialization may not make a large contribution to estimates of total global species richness using methods such as those proposed by Erwin (1982).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1442-9993.2001.01088.pp.x
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  • 5
    Electronic Resource
    Electronic Resource
    Inhumation: how ants and other invertebrates help seeds (1982)
    [s.l.] : Nature Publishing Group
    Nature 297 (1982), S. 627-627 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] WHAT happens to seeds once tl/ey come to rest following dispersal? Seeds are scattered widely in the environment by wind, water, animals and explosive mechanisms and yet the sites where successful germination and growth can occur are often patchy, scarce and limiting1'2. Some possess mechanisms ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/297627a0
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  • 6
    Electronic Resource
    Electronic Resource
    Spatial scaling of microbial eukaryote diversity (2004)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 432 (2004), S. 747-750 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Patterns in the spatial distribution of organisms provide important information about mechanisms that regulate the diversity of life and the complexity of ecosystems. Although microorganisms may comprise much of the Earth's biodiversity and have critical roles in biogeochemistry and ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature03034
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  • 7
    Electronic Resource
    Electronic Resource
    Population consequences of changes in an ant-seed mutualism in Sanguinaria canadensis (1980)
    Springer
    Oecologia 46 (1980), S. 32-37 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Seed dispersal by ants was studied in three populations of the myrmecochore, Sanguinaria canadensis, located in three habitats, each of which showed a different level of disturbance. Frequency of seed removal and the distances seeds were carried by ants were related to plant density, dispersion and the relative proportions of sexual and asexual reproduction in each population. Seeds in the least disturbed habitat were removed frequently and carried, by a wide variety of ants, distances of up to 12 m. Plant density was low and clone size was small. There was a relatively low level of sexual (seed) reproduction but seeds were generally transported well beyond the boundaries of the parent clones. By contrast, at the most disturbed site, plant density was high and clone size was very large. While there was a high level of seed production, seeds were rarely moved by ants and since removal distances were short, the probability of a seed being relocated beyond the limits of the parent clone was miniscule. The third population from a habitat which was intermediate in disturbance yielded data intermediate to the others. The data show that habitat disturbance, in disrupting the ant fauna and hence the ant-seed mutualism, has profound effects upon population density, dispersion and patterns of reproduction. Density-dependent regulation of sexual output predicted, for example, by the Strawberry-Coral model (Williams 1975), is maladaptive when the antseed mutualism is disturbed. We discuss the implications of this for theoretical modeling, the significance of mutualisms and the assessment of disturbance for conservation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00346962
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  • 8
    Electronic Resource
    Electronic Resource
    The nest chemistry of two seed-dispersing ant species (1983)
    Springer
    Oecologia 56 (1983), S. 99-103 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Nests of Myrmica discontinua and Formica canadensis from meadows in the vicinity of the Rocky Mountain Biological Laboratory, Colorado, USA were analysed for fifteen plant macronutrients, micronutrients and heavy metals. Nest samples were compared with control samples taken from surrounding soils. Principal components analysis and discriminant function analysis show that the nest chemistry of F. canadensis differs significantly from that of M. discontinua. Also, nest chemistry differs from that of the surrounding soils. Both kinds of nests contain elevated levels of phosphorus relative to adjacent soils, but F. canadensis nests may be deficient in the micronutrients zinc, iron and manganese. On the other hand, the nests of M. discontinua are also richer in ammonium and percent organic matter. These results are discussed with respect to the hypothesis that relocation of ant-dispersed seeds into ant nests may be advantageous to the plant species involved. It is suggested the relocation to Myrmica nests, rich in phosphorus, potassium and nitrogen, may result in greater survivorship of seedlings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00378223
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  • 9
    Electronic Resource
    Electronic Resource
    Adverse effects on pollen exposed to Atta texana and other North American ants: implications for ant pollination (1988)
    Springer
    Oecologia 75 (1988), S. 153-155 
    Details
    ISSN: 1432-1939
    Keywords: Ant ; Pollination ; Atta ; Antibiotic ; Membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effects of the surface secretions of eight species of ants on three types of pollen were bioassayed by exposure to the integument of undisturbed, living individuals for 20 min. Ant species included Atta texana which cultures fungi by means of various types of secretions. The frequency of grains showing membrane dysfunction, and therefore reduced viability, was quantified by means of a fluorochromatic test. Comparisons of treated and control samples showed that in 46 out of 50 bioassays there was a reduction in pollen viability following exposure to ants, 38 being statistically significant. Variation in the outcome of bioassays showed differential potency among ant species and differential vulnerability among pollen types. Ant pollination may be uncommon because surface secretions, often from the metapleural glands, cause membrane dysfunction in pollen. Ant species without metapleural glands may be pollinators, but ant pollinated plants may have pollen resistant to the secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00378829
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  • 10
    Electronic Resource
    Electronic Resource
    The significance of ant and plant traits for ant pollination in Leporella fimbriata (1990)
    Springer
    Oecologia 84 (1990), S. 457-460 
    Details
    ISSN: 1432-1939
    Keywords: Ant ; Pollination ; Pollen ; Metapleural gland ; Antibiotic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ant metapleural glands secrete surface antibiotics that affect pollen as well as bacteria and fungi. This may be one reason why ant pollination is rare. It is predicted that pollination by ants is possible only in the presence of certain ant and/or plant traits. Two traits are investigated; first, absence of the metapleural glands, and second, the presence of stigmatic secretions that insulate pollen from the ant integument. The pollinator of the orchid Leporella fimbriata is the ant Myrmecia urens. Only one caste is involved, the winged males, and they differ significantly from the queen and worker castes in that they do not possess metapleural glands. This paper reports experiments which test for differential effects on pollen between the males and other castes and evaluates the importance of stigmatic secretions. The results show that the absence of metapleural glands makes no difference as all three castes have strong disruptive effect on pollen artificially applied to the integument. However, during pollination the orchid secures the pollen mass to the ant surface by stigmatic secretions and normal pollen function, fruit production and seed set occur. It appears that both ant and plant traits are pre-adaptive having evolved for functions other than ant pollination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00328160
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