Deceased 30 August 2008
Explaining abundance–occupancy relationships in specialists and generalists: a case study on aquatic macroinvertebrates in standing waters
Article first published online: 19 FEB 2010
© 2010 The Authors. Journal compilation © 2010 British Ecological Society
Journal of Animal Ecology
Volume 79, Issue 3, pages 589–601, May 2010
How to Cite
Verberk, W. C. E. P., Van Der Velde, G. and Esselink, H. (2010), Explaining abundance–occupancy relationships in specialists and generalists: a case study on aquatic macroinvertebrates in standing waters. Journal of Animal Ecology, 79: 589–601. doi: 10.1111/j.1365-2656.2010.01660.x
- Issue published online: 22 MAR 2010
- Article first published online: 19 FEB 2010
- Received 15 May 2009; accepted 10 January 2010 Handling Editor: Tom Webb
- aquatic insects;
- biological traits;
- causal mechanisms;
- core–satellite hypothesis;
- metapopulation dynamics;
- niche breadth
1. A positive interspecific abundance–occupancy relationship is one of the most robust patterns in macroecology. Yet, the mechanisms driving this pattern are poorly understood. Here, we use biological traits of freshwater macroinvertebrates to gain a mechanistic understanding and disentangle the various explanations. We ask whether mechanisms underlying the abundance–occupancy relationship differ between species, and whether information on individual species can be used to explain their contribution to the interspecific relationship.
2. We test the hypothesis that the importance of metapopulation dynamics or niche differences in explaining the relationship differs between species, varying in relation to their habitat breadth. In addition, we analyse how a species’ biological traits shape its habitat breadth and its abundance and occupancy.
3. The abundance and occupancy of the 234 different aquatic macroinvertebrate species were strongly and positively related. Marked differences were found between habitat specialists and habitat generalists in the goodness-of-fit of abundance–occupancy relationships. The occupancy-frequency distribution was bimodal for habitat generalists, allowing ‘satellite species’ to be distinguished from ‘core species’.
4. Habitat generalists appeared to be more widespread but less abundant than habitat specialists, suggesting that the jack-of-all-trades may be master-of-none. Species traits (trophic position and other life-history traits) explained a significant part of the variation around the general relationship. Among habitat specialists, more species showed synchronized life cycles, a low dispersal capacity or clustered oviposition, being better adapted to predictable habitats. Among habitat generalists, more species had long-lived adults, spreading reproductive effort in time and space, and were strong dispersers, being better adapted to unpredictable habitats.
5. Interspecific abundance–occupancy relationships can be best understood by examining the contribution of individual species. For habitat specialists, the interplay between niche differences (diet and habitat use) and the underlying spatial distribution of environmental conditions result in competitive displacement and differences in species’ success. For habitat generalists, differences in colonization and extinction rates between species are more important. Therefore, both metapopulation dynamics and niche differences can operate simultaneously but apply to different species, thus constituting different endpoints of the same continuum.