NCEAS Project Summaries Format: Samples

How Species Coexist in a Competitive World

Principal Investigator: T. Jonathan Davies


Scientific Summary (Long Version):

Explaining species coexistence is one of the principal goals of ecology. Competition is thought to inhibit coexistence among species occupying the same ecological niche. Hence species sharing similar ecological traits are predicted to overlap less in their geographical range. However, the lack of robust null models and the scarcity of appropriate data have meant that the importance of competition in structuring ecological communities has proven hard to evaluate and remains controversial. In addition, other factors may dominate patterns of species overlap and trait similarity; for example, sympatric species might be similar due to convergent evolution as a consequence of sharing a similar environment or they may have only recently diverged, and therefore be similar by descent. Phylogenetic approaches enable the confounding influence of evolutionary history to be controlled for, and provide a simple null model for evaluating the relationship between coexistence and character divergence. This project uses new species-level phylogenetic trees along with extensive databases on species traits and distributions within mammals, to perform global analyses of species overlap and divergence across multiple carnivore and primate communities. Specifically, this project aims to evaluate whether divergence in ecological traits facilitates coexistence in these clades.

Scientific Summary (Short Version):

This project aims to evaluate whether species co-occurrence can be explained by evolutionary divergence in ecological traits. The study will synthesize ecological and evolutionary theory to explore species coexistence for primates and carnivores. Using phylogenetic methods and geographic and biological databases, this research will provide the first global analysis of species coexistence and divergence across multiple communities. This research will address fundamental question s relevant to our understanding of the origin and distribution of biodiversity; for example, what are the ecological and evolutionary limits to local species richness, and do regions of high richness also represent regions of high character diversity?

Public Summary:

Natural communities may consist of hundreds of species. How do all these species coexist and why do some regions support more species than others? Where there is competition for limited resources, such as food, theory predicts that strong competitors will tend to displace competitively inferior species. However, through the evolution of traits that allow initially similar organisms to focus on different food items, competition between species may be reduced, and the numbers of species coexisting in any one area can be increased. This project aims to address two questions. First, which biological traits are important in allowing species coexistence? In particular, the research will focus on traits that might be important in detecting differences in food-use, for example dentition. Second, does coexistence drive evolutionary divergence in biological traits, or does evolutionary divergence in traits allow later coexistence? Assembling information on the evolution, geography and biology of the world's carnivores and primates, this research will provide the first global analysis of species coexistence and divergence across multiple communities. This work will help us to understand the distribution of species richness, and the diversity of form and function found in the natural world.

Number of carnivore species found in different regions across the globe

 Number of carnivore species found in different regions across the globe.

carnivore skull and dentition


Typical carnivore skull and dentition, focussing on the cheek teeth, used in carnivores for slicing meat and thought to be a good indicator of diet.