Project: CAREER: Source-sink dynamics in a restored oyster metapopulation

NSF Award Abstract:
Populations of organisms in different locations are connected by the dispersal of offspring, such as seeds or larvae. Dispersal from populations in favorable environments ('sources') to populations in poor environments ('sinks') can allow the latter to persist where they would otherwise fail to survive. Knowledge about source-sink dynamics is important to conservation and natural resource management. For instance, protecting important source habitats or restoring habitats in locations that enhance connectivity with sinks can improve regional population stability and resilience. Environmental variability and climate change may alter the dynamics of source-sink populations, but the effects of these changes are not well resolved, challenging effective decision-making for habitat conservation and restoration. This CAREER project is using long-term data, multiyear field experiments, biophysical dispersal simulations, and mathematical population models to address several gaps in the understanding of source-sink dynamics in oysters. By partnering with restoration practitioners, the investigator is generating knowledge to optimize oyster reef management in Virginia coastal bays, where the marine environment is rapidly changing. Research methods, data, and specimens are being used to develop a 5th-grade lesson plan on oyster restoration ecology and a 7th-grade field-trip module on oyster biology for public-school students in a rural, high-poverty area of coastal Virginia. Research is also incorporated into an undergraduate restoration ecology class and a course-based research experience for community college students. Research and teaching in this CAREER award are integrated such that students generate data used to advance the science, students receive hands-on training in marine ecology, and scientific samples and findings are used to develop classroom lesson plans.

Temporal variation in the demography and connectivity of source-sink populations has rarely been explored empirically beyond straightforward lab studies. In this CAREER project, the investigator is resolving the patterns, causes, and consequences of temporal dynamics in oyster (Crassostrea virginica) source-sink structure and informing oyster restoration in coastal Virginia. The investigator is testing the hypothesis that temporal heterogeneity -- variation, autocorrelation, and trends over time -- in reproductive output, reproductive timing, and oceanographic forcing alters demographic connectivity through development of a biophysical model of oyster larval dispersal that is parameterized using two decades of environmental and population time series data. Five years of field observations and experiments are determining the drivers of spatial and temporal heterogeneity in the demographic rates that govern source-sink structure -- oyster recruitment, survival, growth, and fecundity. A Bayesian state-space integral projection model parameterized with dispersal estimates and empirical data is being used to test the hypothesis that temporal heterogeneity in dispersal and demography determine regional oyster population dynamics. The investigator is combining models and data with feedback from restoration practitioners to develop spatial planning scenarios that improve oyster population size and stability under future climate conditions.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.