Assessing the Potential of Bat Guano Accumulations as Ecosystem Archives in VA
The Appalachian Mountains, one of the most biologically diverse regions in the temperate world, have been heavily altered by human activity for millennia, but the roles of human impacts, climate change, and natural disturbances in creating modern Appalachian landscapes are not yet well understood. Holocene paleoenvironmental records are urgently needed for this region to provide a window into past vegetation and landscapes, however such records are severely limited by the paucity of paleoenvironmental indicators, such as natural lakes. Recent research suggests that cave guano deposits, which can accumulate over millennia, can serve as valuable archives of past environmental changes where such records have previously been scarce. Guano records have the additional capacity to provide information about bat communities over time, and therefore have potential to provide archival information about historic species occupancy, abundance, and health of bats (e.g., the appearance of white-nose syndrome, an emerging bat fungal disease).
This pilot study will compare cave guano-derived proxy records with both a cave sediment record and a nearby lake/wetland sediment core record to evaluate the potential of guano cores as ecosystem archives. Our primary research objectives are to 1) conduct site visits and collect preliminary samples to identify the best location for continued work, and 2) evaluate guano derived proxy records compared with those obtained from lake and cave sediments. We are particularly interested in documenting vegetation shifts in southern Appalachia over the past several thousand years and the degree to which the three archives agree. We hypothesize that 1) archives will preserve overlapping information about past environments, but reflect varying spatial scales, with bats foraging at the km scale potentially sourcing material from a larger area (102-103 km2) than a small lake (101-102 km2) or cave (10-2-10-1 km2); and 2) that guano cores will reflect the arrival of P. destructans, the cause of white-nose syndrome, to bat populations in recent time (<10 years), providing validation of the temporal information provided in guano cores by using a pathogen with known arrival dates.
Cave guano deposits represent a promising paleoenvironmental archive that has yet to be explored in Virginia. This project brings together a multidisciplinary group of scientists with expertise in Virginia caves, paleoecology, stable isotope biogeochemistry, and disease biology to characterize the guano record through rigorous comparison with longstanding archives. Based on our findings, we plan to pursue funding to build a network of guano core records from caves throughout the Appalachians to generate quantitative estimates of the relative abundance of forests versus grasslands in the past as well as document past fire history.
Reference citations for project proposal description available upon request.