Intellectual Merit:

Why does biological diversity tend to increase towards the tropics and decrease towards the poles? The reasons for this pattern have been debated and likely involve a combination of environmental conditions but also the degree of competition among species over shared resources. We set out to answer this question with a unique dataset from the National Ecological Observatory Network (NEON), consisting of small mammals across the United States and measures of their body sizes.  We found that although temperature explained some of the variation in diversity at the continental scale, it was the degree of competition that explained the most variation in diversity, represented by the degree to which species overlapped each other in body sizes. Our findings imply that increased mammal diversity is enabled by species-specific specialization on resources to avoid competition, which tends to be more intense in warmer regions. This insight would not have been possible without explicitly accounting for individual body sizes and leveraging a continent-wide observational network; most classic work on species coexistence used only species mean body size values within a single ecosystem.

Ultimately, understanding and forecasting the patterns of biodiversity across the globe requires incorporating both environmental and biological drivers of species distributions. Yet biological drivers are rarely incorporated into models predicting species distributions. Through a meta-analysis, we identified key knowledge gaps in this area and highlight research needed to advance models through incorporating interactions among species (like predation, competition, and pollination), and dispersal abilities of species. In addition, we developed a framework that connects habitat structure and the configuration of human land use with the ability of species to interact with each other, improving our ability to explain patterns of biodiversity and species distributions from local to global scales. Finally, we improved fundamental understanding of marine predator diversity patterns across the globe, based on predator-prey relationships, animal physiology, and climate.

Broader Impacts:

In all, three peer-reviewed publications resulted from this award, and involved graduate and postdoc authors in addition to the PIs. We placed a high priority on open science, including open access publications, and data and code for analyses deposited in public repositories. Graduate students and postdoctoral associates were involved in this research through data collection, analysis, interpretation, manuscript writing, and presentation of results through peer-reviewed manuscripts and oral and poster presentations at local to international conferences.

We reached scientific audiences through numerous talks at universities and local to international scientific conferences, and through an organized session at the Ecological Society of America, ?Challenges and opportunities for investigating ecological communities across space and time: insights from coordinated research networks.? 

Last Modified: 04/30/2019
Modified by: Angela Strecker