Professor Oregon State University Corvallis, Oregon, United States
Abstract: Understanding how disturbance events impact community organization is crucial for management and conservation of aquatic species. Predictable natural disturbance regimes (NDR), such as the seasonal filling and drying of ponds, play a central role in shaping the evolutionary life histories of organisms. We posit that NDRs prime communities with resilience mechanisms such as species and trait diversity, to better respond to climate change disturbance. Heightened species richness increases the number of possible functional traits and asynchronous species responses available in a system, enhancing the chance of resistant species able to compensate for the loss of vulnerable species. Body size is an important trait regulating physiological and behavioral outcomes and can shift in response to environmental cues, producing feedback across ecological scales in both aquatic and terrestrial systems. Thus, body size provides an ecologically important metric for phenotypic flexibility that can be easily measured across taxa. To compare diversity mechanisms in temporary and permanent ponds, we measured species richness (species diversity) and body size (trait diversity) in fish, amphibians, and aquatic macroinvertebrates in ponds across the Willamette Valley, OR. We hypothesized that communities in temporary ponds, experiencing more frequent NDRs, will be more species rich and exhibit higher body size variability compared to communities in permanent ponds. We used MRPP and NMS to test for and visualize differences in community structure. We found inverse differences in species and trait diversity between the two pond types. These observations will inform mesocosm experiments examining community-level climate change resiliency thresholds. Altogether, this in situ comparison of species richness and size structure, paired with future experimental exploration of resiliency thresholds will provide insight into community-level response to disturbance, with implications for the importance of phenotypic flexibility, species diversity, or the convergence of both mechanisms in resilience to climate change.
