Understanding species distribution and diversity: insights from temporal occupancy

Understanding the processes underlying community assembly is one of the primary goals of ecology. Studying communities can be complex because they often encompass a diverse array of interacting taxonomic groups and trophic levels. Additionally, community makeup changes in response to disturbances, environmental factors, interspecies interactions, and anthropogenic alterations to habitat. Despite these challenges, discovering the drivers of community assembly and dynamics will improve our ability to understand how ecosystems function and conserve biodiversity effectively. Typically, characterizing community assembly uses species abundance, which provides information about which species are currently present in the community, but does not address which species are consistent members of a community versus species poorly suited to the habitat they are observed in. This distinction is critical when considering questions such as estimating community biodiversity, community composition, and temporal turnover. One way to address this issue is by using the metric of temporal occupancy, or how frequently a species is observed at a given site within its community. To understand how temporal occupancy affects our understanding of ecological systems, I tested the prevalence and impact of species who appear infrequently in their communities, or transient species, on classic ecological patterns such as species abundance distributions, species richness correlation with environmental heterogeneity, temporal turnover, and species-area relationships using 7 taxonomic groups. Once these patterns have been examined from the perspectives of transient and non-transient species from a diversity of communities, I investigated the abiotic and biotic determinants of avian temporal occupancy in North America. Then, I applied the metric of temporal occupancy to commonly used species distribution models (SDMs) to determine whether avian species distributions are better predicted using temporal occupancy as opposed to presence and absence. Finally, I tested whether temporal occupancy provides robust inferences for identifying core and transient species using simulations. I simulated species dynamics over time with varying habitat heterogeneity and detection to understand core and transient structure within a community without the added noise of a biological system. Together, these studies improve scientific insight into community ecology and allow us to predict how communities will respond to disrupting factors.Doctor of Philosoph