4 results
FORUM: THE ARBOREAL SUPERHIGHWAY: ARTHROPODS AND LANDSCAPE DYNAMICS
- Neville N. Winchester
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- Journal:
- The Canadian Entomologist / Volume 129 / Issue 4 / August 1997
- Published online by Cambridge University Press:
- 31 May 2012, pp. 595-599
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Species richness of arthropods in northern temperate coastal rain forests far exceeds previous estimates, and the functional significance that these species play in ecosytem processes remains largely unknown. Examination of several species, many of which are not yet described, indicates that these intact ancient rain forests are structurally complex and act as reservoirs for biological diversity. Forest harvesting and resulting fragmentation affects arthropod diversity by altering key patterns of natural processes which are inseparably linked to habitat diversity. Consequences for arthropods may vary but those species which are endemic or inseparably linked to habitat features found only in these forests are particularly vulnerable to fragmentation-induced changes. Several important questions arise. What are the implications of forest fragmentation on ecological processes? What role does dispersal play in arthropod population viability? Given the immense biodiversity of arthropods, what are the functional roles that the species play in these forests and how are these changed when forests are harvested? The lack of empirical evidence makes it difficult to answer these questions and to quantify the functional roles of arthropods in these ecosystems.To address these questions, I suggest that studies should not rely on single-species approaches and the measurement of diversity (i.e. species richness and abundance) but should focus on addressing the functional roles of forest arthropods. To move beyond the basic description of pattern I suggest that studies concentrate on describing species assemblages while including dynamic processes such as dispersal into the framework of how we think about arthropods in ancient forests. The use of feeding guilds in the development of predictive models may give us an understanding of these factors and provide information that could be used to examine functional patterns in community structure.
Diversity of Placusa (Coleoptera: Staphylinidae, Aleocharinae) in Canada, with descriptions of two new species
- Jan Klimaszewski, Georges Pelletier, Carole Germain, Christian Hébert, Lee M. Humble, Neville N. Winchester
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- Journal:
- The Canadian Entomologist / Volume 133 / Issue 1 / February 2001
- Published online by Cambridge University Press:
- 31 May 2012, pp. 1-47
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The Canadian species of the genus Placusa Erichson are reviewed. Eight species are recorded, of which four constitute new Canadian records (P. despecta Erichson, P. incompleta Sjöberg, P. petulans Casey, and P. vaga Casey) and two are new to science (P. pseudosuecica Klimaszewski sp.nov., and P. canadensis Klimaszewski sp.nov.). Placusa turbata Casey, one of the two species previously recorded from British Columbia, is here considered a synonym of P. tachyporoides (Waltl) and is reported for the first time from eastern Canada (New Brunswick, Ontario, Quebec). New data are provided on the systematics, distribution, bionomics, and relationships of selected North American species. A key to the species occurring in Canada is presented with illustrations of the median lobe of the aedeagus, spermatheca, male tergite 8, antennae, and outline drawings of the head and adult forebody for each species. Selected Palearctic species are also illustrated for easy comparison with the closely related Nearctic species. The Canadian distribution is presented on contour maps, and world distribution is discussed for all species. The following lectotypes are designated for the Nearctic species which were described from more than one specimen without former holotype designation: Casey (1893, 1911): P. frosti, P. strata, P. tacomae, P. turbata; Erichson (1840): P. despecta; and Sachse (1852): Oxypoda minuta Sachse. Oxypoda minuta is transferred to the genus Placusa and newly synonymized with P. despecta Erichson (1840).
Ancient temperate rain forest research in British Columbia1
- Neville N. Winchester
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- Journal:
- The Canadian Entomologist / Volume 138 / Issue 1 / February 2006
- Published online by Cambridge University Press:
- 02 April 2012, pp. 72-83
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This paper is a tribute to Dr. R.A. Ring upon his retirement. During the past 12 years (1993–2005), an emerging canopy research program has established a wealth of baseline information on the structure and functioning of temperate rain forest canopy arthropod communities. Studies from research sites on Vancouver Island, British Columbia, have shown that ancient temperate rain forest canopy ecosystems contain a largely undescribed fauna that is specific to habitat features found only in these canopies. In particular, diverse assemblages of free-living mites have been shown to dominate conifer species and canopy microhabitats. For example, oribatid mites are the dominant arthropod fauna on branches, branches with attached lichens, and suspended soil accumulations. Species composition differs significantly between the ground and the canopy at both the family and the species level. Arboreal specificity may be due to intrinsic variation in habitat quality, habitat architecture, patchiness, and (or) resource availability. The prevalent patterns of habitat specialization, low vagility, and restricted distribution displayed by a large percentage of the resident canopy microarthropods are features often associated with forest ecoregions that have enjoyed relatively stable conditions for long periods of time, as have the ancient forests on Vancouver Island. Investigators in the “one-Ring lab” continue to document the diversity and abundance of canopy arthropods of temperate forests in British Columbia. In particular, studies are concerned with defining the organizing principles that elicit community patterns associated with the various levels of complexity in arboreal communities. Our long-term goal is to provide a greater degree of predictability when addressing temperate forest diversity issues. To meet the stated goals of sustainable forest management and retention of biodiversity, an extensive plan of ecological research that features arthropods is needed. This plan, fostered by Dr. Ring, should have as a priority the inventory and cataloguing of species assemblages and should address dynamic processes such as organismal dispersal and the effects of habitat loss and fragmentation on arthropods in ancient forests.
Environmental and spatial influences upon species composition of a termite assemblage across neotropical forest islands
- Richard G. Davies, Luis M. Hernández, Paul Eggleton, Raphael K. Didham, Laura L. Fagan, Neville N. Winchester
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- Journal:
- Journal of Tropical Ecology / Volume 19 / Issue 5 / September 2003
- Published online by Cambridge University Press:
- 23 September 2003, pp. 509-524
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Patterns of species composition in a neotropical termite assemblage were studied in relation to early effects of forest fragmentation as well as other sources of environmental and spatial heterogeneity. Termite diversity surveys were carried out at three mainland forest sites, and 10 islands of varying size, in an area of lowland tropical forest that had been flooded 4 y earlier, during the creation of the Petit Saut hydroelectric project in French Guiana. The ‘ghost forest’ of dead emergent trees in the flooded zone was also studied for its influence on island termite assemblages. Results suggested that the effects of forest fragmentation upon the total assemblage, and upon soil-feeders in particular, were subordinate to the influence of forest understorey palm density, and the closely associated gradients of soil humus depth and soil pH. Moreover, gradients for these three variables were uncorrelated with forest fragmentation and probably reflected spatial environmental heterogeneity pre-dating inundation events. Nevertheless, factors associated with forest fragmentation appeared to have had a significant effect on changes in termite species composition across the study site, primarily in structuring the wood- and leaf-litter-feeder assemblage. Effects upon the latter were not apparently a result of influx of species from the ghost forest. Purely spatial variation also influenced β-diversity changes in species composition across the site. In conclusion, the effects of forest fragmentation upon termites appear to have been relatively mild compared with other faunal groups, 4 y after flooding. Nevertheless, we predict that the effects of fragmentation on termite assemblages will ultimately be negative. This study also points to the importance of Amazonian understorey palms in structuring a tropical forest termite assemblage.