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Mammal community structure in a world of gradients

effects of resourse availability and disturbance across scales and biomes

Wallgren, Märtha (2008). Mammal community structure in a world of gradients. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2008:59
ISBN 978-91-85913-92-3
[Doctoral thesis]

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Functional types are becoming central when searching for generalities in community ecology. They may help in identifying the driving factors that shape communities, as well as in formulating ecological rules. In this thesis I show that functional types of mammal species may determine the species’ responses to various environmental gradients, such as of resource availability and disturbance. My data originate from two contrasting regions of the world, the arid savannas of southern and eastern Africa and the boreal forest of central Sweden, and comprise different spatial and temporal scales. Methods include distance sampling technique, wildlife triangle census, small mammal trapping, vegetation survey and GIS-analysis. Mammal community species richness is lower in the boreal forest than on the savanna. The boreal forest ecosystem is also characterized by few species of herbivores, while the number of predators is high. In the savanna the herbivores dominate. In comparison with savannas the boreal forest is a low productive, homogeneous habitat with a high dominance of two tree species and may thus support merely a low diversity of herbivores. However, the predator diversity seems little affected by prey species diversity and is probably more so by biomass of prey. I found indications that the Jarman-Bell principle, formulated for savanna ungulates, also applies to herbivores in the northern boreal forest. It states that due to metabolic constraints, small-sized herbivores, especially foregut fermenters, will dominate in nutrient-rich areas and large-sized herbivores, especially hindgut fermenters, in nutrient poor areas. The results show that under high-nutrient conditions most boreal herbivores belong to the smaller of two mass classes, while there was no pattern under low-nutrient conditions. The smaller herbivores, as well as the foregut fermenters, also contributed to a larger proportion of the metabolic biomass in the nutrient-rich, compared with the nutrient-poor, area. In summary, my results suggest similarities as well as differences between the structuring factors and processes of mammal communities depending on spatial scale and biome. I recommend that future research in community ecology center around multi-species approaches, including multiple functional types, also for questions which are traditionally restricted to few-species relationships.

Authors/Creators:Wallgren, Märtha
Title:Mammal community structure in a world of gradients
Subtitle:effects of resourse availability and disturbance across scales and biomes
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2008
Number of Pages:46
ALLThis thesis is based on the work contained in the following papers, referred to by Roman numerals in the text: I Wallgren, M., Skarpe, C., Bergström, R., Danell, K., Granlund, L. & Bergström, A. Mammal community structure in relation to disturbance and resource gradients in southern Africa. African Journal of Ecology (In Press, Published electronically). II Wallgren, M., Skarpe, C., Bergström, R., Danell, K., Bergström, A., Jakobsson, T., Carlsson, K. & Strand, T. Influence of land use on the abundance of wildlife and livestock in the Kalahari, Botswana. (Submitted revision). III Wallgren, M., Bergström, R., Danell, K. & Skarpe, C. Wildlife community patterns in relation to environmental gradients and method of monitoring in a Swedish boreal ecosystem. (Submitted manuscript). IV Wallgren, M., Skarpe, C., Stokke, S., Danell, K., Bergström, R., Swenson, J., Motsumi, S. & Røskaft, E. Composition of body masses in two African ungulate communities - A test of the Jarman-Bell principle. (Manuscript). Papers I is reproduced with the permission of the publishers.
Place of Publication:Umeå
ISBN for printed version:978-91-85913-92-3
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:mammals, animal ecology, population ecology, savannas, boreal forests
Keywords:boreal forest, carnivores, community ecology, functional type, herbivores, Jarman-Bell principle, mammal, savanna, ungulate, wildlife
Permanent URL:
ID Code:704
Department:(S) > Dept. of Wildlife, Fish and Environmental Studies
Deposited By: Kristina Johansson
Deposited On:03 Oct 2008 00:00
Metadata Last Modified:02 Dec 2014 10:06

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