Evol Ecol Res 5: 469-492 (2003)     Full PDF if your library subscribes.

A unified theory for macroecology based on spatial patterns of abundance

Brian McGill1* and Cathy Collins2

1Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721 and 2Yosemite National Park, PO Box 907, CA 95389, USA

Author to whom all correspondence should be addressed.
e-mail: mail@brianmcgill.org


Macroecology proceeds by identifying patterns and then identifying processes that cause those patterns. Most of the processes that macroecologists study are local in nature and tend to involve species interactions and speciation and extinction processes. In contrast, we propose that several important macroecological patterns can be explained by very large-scale processes that are primarily spatial in nature. Specifically, we suggest that the structure of abundance across a species’ entire range combined with interspecific patterns in range location and global abundance can explain the well-known macroecological patterns of: (1) a positive correlation between range size and abundance, (2) the species–area relationship, (3) decay of species similarity with distance and (4) the species abundance distribution. We show that spatial processes produce these patterns through a combination of analytical and Monte Carlo analysis. We also show that the connection is robust (indifferent) to the precise mathematical assumptions. Such a theory might be called a unified theory, because it explains multiple patterns with a few processes. To differentiate among the growing number of unified theories, we suggest that testing additional predictions over and above producing curves of the correct shape is important. To this end, we present several novel, quantitative predictions and provide empirical tests. In short, we provide an empirically grounded and tested theory, which suggests that superimposing individual species ranges across space creates local community patterns.

Keywords: macroecology, species abundance distribution, species–area relationship, species range, unified theory.

IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.


        © 2003 Brian McGill. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

       Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.

       All copies of abstracts and articles must preserve their copyright notice without modification.