CAN CAVE ECOSYSTEMS IMPROVE OUR UNDERSTANDING OF KARST PROCESSES?

Patterns in biological communities have long been studied and traced to variability in physical habitat. In subterranean ecosystems, the evolution of unique species and distinct communities is often tied to the lack of connectivity between caves. Although this link between biology and geoscience has long been used to understand biological systems, it has yet to be used to inform the understanding of physical processes and connectivity between caves or karst groundwater basins.

We tested the ability of macro-invertebrate data to reflect patterns in cave development and habitat connectivity. Caves in the Kaweah River Basin, California are formed in thin bands of marble that are distinct from each other, with multiple caves per marble band. We hypothesized that species in caves in the same bands of marble would be more similar to each other than to species in caves in other marble bands as a result of increased connectivity of habitat between caves in the same band. A pair-wise Jaccard analysis was conducted to assess similarity of species composition, using biological inventory data from 30 caves in Sequoia and Kings Canyon National Parks. We then assessed which combination of spatial variables, as a proxy for cave connectivity, best explained patterns in (1) species richness and (2) species composition of each cave.

Results indicate that lower-elevation caves that are in larger bands of marble (a metric of habitat availability) have higher species richness and lower endemism and caves that are in smaller bands of marble and at higher elevations have lower richness and higher endemism. These results suggest that lower-elevation caves have higher connectivity as a result of past speleogenetic processes, which is represented in the biological communities in the caves. This suggests that cave ecosystems have the potential to inform us about speleogenesis and karst hydrologic processes.