Range Limits and Population Dynamics in Estuarine Animals

 

About half of the lab studies the evolutionary ecology of range limits, which are critical to our understanding of basic ecology and evolutionary biology, and also to predict ecosystem response to ongoing climate change.  The limits to the range of a species may be set by extreme physical conditions that cannot be tolerated, by biological interactions (a lack of food, or presence of a dominant competitor), and by barriers to migration (a species cannot physically make it to more distant locations where suitable habitat is found).  Understanding the genetic constraints preventing adaptation to conditions beyond the range edge is a major goal of evolutionary biologists.  From a conservation perspective, species all over the planet have undergone dramatic shifts in their ranges in recent decades in response to climate change, with ranges typically shifting poleward as organisms track their climate niche - i.e., the temperature range within which they can survive.  Predicting ecosystem response to climate change requires a detailed understanding of the various factors that interact to set range boundaries, yet we know relatively little about such factors for marine coastal animals.

 

 

 

 

 

 

 

 

 

 

 

 

Our goal is to better understand how tolerance for the physical environmental, biological interactions, and delivery of larvae by coastal currents together set limits to the geographical range of species along the U.S. Pacific coast.  We are studying the physiological and ecological basis for range limits in estuarine animals, which are exposed to both high temperatures in spring/summer, and low salinity during winter rains, when low tides expose mudflats to the harsh physical environment.  Our model system comprises two sea slugs in the genus Alderia, common on mudflats where they eat the dark green alga Vaucheria.