NEON organismal data provide a unique opportunity to ask continental-scale questions about how the environment mediates spatial patterns of communities and biodiversity. We used NEON small mammal organismal data at the individual level, and multiple taxa at the species level to understand the potential drivers of such patterns. The goal of the research was twofold: 1) to develop a community measure of individual-level overlap in trait values that maps to niche breadth and overlap, and 2) assess the NEON organismal data for its representation of known patterns of biodiversity at each site and within each climate domain. In developing a community measure of trait overlap, we used individual morphological measurements of small mammal species’ body sizes at each NEON site. We then inferred connections among population-level intraspecific trait variability, niche overlap, and environmental drivers at the continental scale. Species-level occurrence records for available taxonomic groups at each NEON site were assembled to quantify diversity measures within each site and NEON domain, and contrasted with other occurrence data sources (e.g., IUCN range maps). Species accumulation curves were used to assess the degree that NEON organismal data reflect the local species pool.
Results/Conclusions
We 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. This implies that a greater number of species can coexist when they utilize different resources, and that warmer, more stable environments promote specialization that reduces competition. This result provides a possible explanation for the larger number of species found in warmer regions. Observed richness of plant species in NEON vegetation plots aligned reasonably well with the background richness of the regional species pool, but the richness of the mammal regional species pool was a poor predictor of the observed mammal richness in NEON plots. However, species accumulation curves indicated that most NEON sites (all but 3 of 23 sampled) capture the full complement of locally occurring mammal species. The combination of individual-level and species-level data in NEON provides a means to understand how organisms are organized and distribute across major environmental gradients.