Aava Olsson, Birgitta
- Department of Animal Ecology, Swedish University of Agricultural Sciences
This thesis focus on the effects of plant productivity on various aspects of geographic range size, resource use, body size and abundance of animal species from different taxa, from a local to a global scale. The aim was to identify putative scales to determine whether it is possible to find functional links between plant productivity and species richness by considering how productivity affects species characteristics for different assemblages, e.g. mammals, insects and birds.
Terrestrial endemic mammal genera in the world appeared to be most common in zoo-geographic regions of intermediate plant productivity (Paper I). I could not find evidence that Australian herbivorous mammals either combine food resources in more ways or are more selective in areas of high plant productivity (Paper II). Although, these Australian herbivorous mammals were larger and more similar in size in biomes of high plant productivity than in low (Paper HI). I further, found that for two families of ground dwelling Coleoptera plant productivity does not have any effect on the relationship between number of individuals and number of species within body size classes in local forest sites (Paper IV). There was a trend that higher productivity sites could hold more individuals of large sized species, but not more species. The reverse trend was observed for small sized species. Breeding forest birds in Sweden had highest average densities in areas of both low and high plant productivity (Paper V). Also, species with a lower than expected from their range size were mainly found in areas of high plant productivity while the reverse was true for species with higher than expected abundance.
Finding functional links between observed patterns of animal characteristics and between species richness and productivity are vital to our understanding of how the transfer of energy from plants to animals affects the distribution of species. The spatial scale at which to study the mechanisms does influence how these proposed functional links will be affected by productivity. In this thesis I show that changes in productivity are likely to induce complex interactive changes in all key attributes, rather than clear linear responses. I therefore suggest that future studies should consider all these attributes in conjunction.
plant productivity; range size; resource use; body size; abundance; endemism; species richness; mammals; insects; birds; forests; scale
Acta Universitatis Agriculturae Sueciae. Silvestria
2001, number: 200
Publisher: Department of Animal Ecology, Swedish University of Agricultural Sciences