Davinack Research Group @ Wheaton College
BARCODE Program: incorporating DNA barcoding into biomonitoring surveys
The ability to detect a non-indigenous species as early as possible in its recipient environment is a crucial part of preventing an invasion event. As a result routine biomonitoring is often a recommended step for environmental authorities when assessing community and ecosystem health. However, cryptic complexes can complicate biomonitoring of certain taxa, especially those that exhibit high levels of diversity. Consequentially, the incorporation of molecular data becomes an invaluable tool for developing more robust presence/absence data either through traditional DNA barcoding methods or metabarcoding/e-DNA barcoding pipelines. The incorporation of DNA barcoding into the New England Rapid Assessment Surveys, sponsored by the Massachusetts Office of Coastal Zone Management has resulted in the detection of several polychaete species that were either overlooked in past surveys due to lack of taxonomic expertise or were recent arrivals to the region. In the Adirondack Park, the largest protected forested reserve in the contiguous United States, undergraduates in the Davinack Lab used DNA barcoding to make several important discoveries which included the first report of the freshwater gastropod, Sinotaia cf. quadrata in the United States and showed that two mystery snails, not one (as was previously thought) was present in the lakes and rivers in the region. The BARCODE program is an excellent way to get undergraduate students interested in molecular biology as it allows them to design their own questions and hypotheses, while also working with real animals
CONNECT Program: Exploring cryptic dispersal in aquatic environments
The large-scale anthropogenic movement of marine and freshwater fauna across different biogeographic regions is one of the greatest threats facing global biodiversity. While the ecological impacts of these introductions have been well documented and are often the main focus of invasion biology research, a more hidden threat, specifically the genetic homogenization of species, has garnered much less attention. The presence of dispersal barriers across seascapes and riverscapes maintains the genetic structure of a species and over time allows for the diversification of lineages. Limited dispersal across these barriers (‘leakage’) may allow for the maintenance of a coherent but diverse evolutionary unit. In nature, these patterns are often in flux, and large scale changes can only occur over geological time scales where events such as sea level rises, can change the course of a species’ evolutionary trajectory. However, with increases in marine traffic across the globe and the growing aquaculture industry, marine organisms are being moved across natural barriers at a breathtaking pace. Such rapid and consistent bidirectional movement across these barriers have the potential for skewing phylogeographic patterns of a species towards a panmictic state. As a consequence, detecting whether a specific genetic pattern is due to natural movement, anthropogenic movement or both is crucial for making conservation decisions
CLIMATE Program: Experimental investigation into the physiological effects of climate change stressors on aquatic invasive species
While phylogeography and molecular barcoding allows us to detect new invasive species and track their spread, it does not tell us why a non-native species thrives in its introduced range. To answer this question, the David Lab has been investigating the physiological tolerance of invasive species by culturing animals under climate change stressors and measuring responses. We have used indirect methods for measuring tolerance such as regeneration rates of polychaete worms after amputation under varying salinity regimes, larval survivorship and developmental of polychaetes under varying temperature regimes and shell repair rates of freshwater gastropods that were intentionally damaged under varying pH regimes
Photographs showing shell regeneration in a freshwater gastropod under elevated carbon-dioxide induced acidification (pH drop of 0.5). Adopted from David et al. 2020 Journal of Molluscan Studies 86: 259-262.
Photographs showing regeneration of anterior tissue after amputation in spionid Marenzelleria viridis under varying levels of salinity. Note that pigmentation patterns varied significantly and was different from the original anterior end, indicating that this morphological trait may not be taxonomically formative for this species. Adopted from David and Williams 2016 Marine Ecology 37: 821-830.