Rodents overlap less in their body size distributions in more diverse communities--could this hold a clue to explaining diversity patterns?

Submitted by editor on 12 March 2018. Get the paper!
Juvenile Microtus pennsylvanicus, North Dakota

By Quentin Read

Ecologists have collected reams of field data, involving much sweat and toil, to explain how competing species — those with similar diets or habitat preferences — can coexist without driving each other to extinction. A longstanding, but difficult to test explanation is that species with different traits have different requirements, or different "niches," which reduces competition for resources and promotes coexistence. For instance, small foxes eat mice and large wolves eat elk; their difference in body size reduces competition for food and allows them to coexist in the same habitat.

Microtus oregoni with a NEON ear tag, Washington.

Measuring the weight of Peromyscus keeni, Washington.

This study examines the issue using a meeker but more diverse group of mammals: rodents. Using individual body size measurements from small mammal trapping conducted across the USA by the National Ecological Observatory Network (NEON), researchers quantified the overlap of rodent body size distributions to understand patterns of diversity. The researchers found that body size distributions of co-occurring rodents tend to overlap less in warmer areas and in places harboring a more diverse rodent community. The results imply that a greater number of species can coexist when they specialize on different resources, and that warmer environments promote specialization that reduces competition. This finding offers an explanation for the global pattern that larger number of species are found in warmer regions.



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