Meeting Abstract
Land conversion alters water quality variables in freshwater habitats and may have negative consequences on population health of aquatic organisms. Populations exposed to land use conversion may have different abilities to modulate their stress response and their ability to recover (resilience) from stressors. Glucocorticoids, such as corticosterone, play a role in modulation of the immune system, and the level of corticosterone can be used to assess the overall stress and health of their populations. We measured baseline, stress response, and resilience corticosterone release rates in common toad, Bufo Bufo, tadpoles from ponds in agricultural, urban, and rural habitats. We also reared eggs from the ponds in a common garden design and measured corticosterone in the developed tadpoles. We hypothesized that tadpole corticosterone release rates would differ between converted habitats and rural habitats. We found that corticosterone was highest in tadpoles from urban ponds and lower in rural and agricultural ponds. All populations showed a stress response and resilience indicating that they are not chronically stressed. The fitness consequences (body condition) to resilience and stress response varied across populations. Corticosterone release rates were repeatable, indicating the ability of this trait to respond to selection. Corticosterone was lower in tadpoles from mesocosms and did not differ by original land use type, suggesting that differences observed in the natural populations were primarily associated with environmental conditions.
