Present address: School of Biological Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK. E-mail: firstname.lastname@example.org
The life-history basis of latitudinal diversity gradients: how do species traits vary from the poles to the equator?
Article first published online: 5 MAR 2002
Journal of Animal Ecology
Volume 71, Issue 1, pages 79–87, January 2002
How to Cite
Cardillo, M. (2002), The life-history basis of latitudinal diversity gradients: how do species traits vary from the poles to the equator?. Journal of Animal Ecology, 71: 79–87. doi: 10.1046/j.0021-8790.2001.00577.x
- Issue published online: 5 MAR 2002
- Article first published online: 5 MAR 2002
- Received 12 March 2001; revision received 20 September 2001
- geographical range;
- phylogenetically independent contrasts;
- species richness
1.Latitudinal variation among species in life-history traits is often suggested to contribute to high tropical species richness. However, traditional methods of analysing such variation rarely control for phylogeny and latitudinal range overlap between species, potentially giving misleading results.
2.Using a method of pairwise independent contrasts which overcomes these problems, I tested for latitudinal variation among bird species in a number of traits which have been linked, theoretically or empirically, with both latitude and species richness.
3.This method indicates strong support for Rapoport’s Rule and decreasing clutch size towards the equator in both hemispheres, but only partial support for decreasing body size and ecological generalism towards the equator.
4.Indirect measures of sexual selection (sexual dichromatism and size dimorphism) show no variation with latitude; an apparent increase in dichromatism towards the equator is shown to be an artefact of phylogeny.
5.Many of the associations between life history and latitude were not detected by traditional cross-species analyses, highlighting the importance of incorporating phylogeny and overlap in studies of geographical life-history variation. Establishing associations between life-history traits and latitude does not prove, but is a necessary prerequisite for, a link between these traits and latitudinal diversity gradients.