Is the Rapoport effect widespread? Null models revisited
Article first published online: 24 OCT 2006
Global Ecology and Biogeography
Volume 15, Issue 6, pages 614–624, November 2006
How to Cite
Ribas, C. R. and Schoereder, J. H. (2006), Is the Rapoport effect widespread? Null models revisited. Global Ecology and Biogeography, 15: 614–624. doi: 10.1111/j.1466-8238.2006.00265.x
- Issue published online: 24 OCT 2006
- Article first published online: 24 OCT 2006
- mid-domain effect;
- null models;
- Rapoport effect;
- range size
Aim To test the Rapoport effect using null models and data sets taken from the literature. We propose an improvement on an existing method, testing the Rapoport effect in elevational and latitudinal distributions when distributions are restricted by sampling.
Methods First, we hypothesized that real range size distributions are similar to those expected by null assumptions (expected by only imposing boundaries to species distributions). When these distributions were different from those expected under the null assumptions, we tested the hypothesis that these distributions correspond to those expected when a Rapoport effect occurs. We used two simulation methods, random and pseudo-random, which differed only in that the latter one assumes fixed species mid-points, coinciding with real mid-points. Observed correlations between range size and mid-point were compared with the frequency distribution of 1000 simulations, using both simulation methods. We compared the correlation curves generated by 1000 simulations with those of the observed distributions, testing whether correlations indicated a Rapoport effect.
Results Several significant patterns of correlations between range size and mid-point were observed in the data sets when compared with random and pseudo-random simulations. However, few of these correlations were consistent with a Rapoport effect.
Main conclusions Although some recent studies are consistent with a Rapoport effect, our results suggest that the Rapoport effect is not a widespread pattern in global ecology.