Modeling Salmonid Population Persistence Across the Streamscape

Date: Thursday, March 22, 2012, 12:00 noon - 1:00 p.m.

Title: Modeling Population Persistence Across the Streamscape

Presenter: Ben Letcher, Population Ecologist, Silvio O. Conte Anadromous Fish Research Center, USGS

Abstract: Accelerating environmental change resulting from population pressures and climate shifts makes reliable forecasts of population response to change now more important than ever. Reliable and useful forecasts identify the magnitude, direction and uncertainty of predicted population response under a variety of future scenarios across a range of habitats. Working with the North Atlantic Landscape Conservation Cooperative (LCC), we are developing models that can reliably forecast effects of future scenarios on population growth and persistence of stream dwelling salmonids. The major environmental drivers for stream fish are stream temperature and stream flow, which respond in complex ways to the physical forcing factors local geology, land use, water withdrawals, air temperature and precipitation. We have developed stream temperature and flow models that respond to these physical forcing factors and provide the necessary link between physical forcing on the landscape and fish population response. We have also developed detailed demographic models that culminate in an estimate of population growth (can be positive or negative) based on the responses of fish body growth, movement, survival and reproduction to temperature and flow. With these linked, integrated models we can forecast population response to changes in land use (provided by the terrestrial North Atlantic LCC project), climate change (acting through air temperature and precipitation) and other disturbances (including water withdrawal or mitigation strategies). Importantly, these linked models provide forecasts of the magnitude, direction and uncertainty of population growth. These forecasts will be useful for both evaluation of alternate management strategies and creation of maps of susceptible and resilient watersheds. In phase I of this project, we are applying these models to selected watersheds within the North Atlantic LCC. We will describe the models and provide preliminary results.

Bio: Ben Letcher is the head of the Ecology Section at the USGS Conte Anadromous Fish Research Center and an adjunct associate professor in the Department of Environmental Conservation at the University of Massachusetts Amherst. He is interested in demography and evolution of stream fishes and in the development of tools for natural resource management. Since 1997, he has led efforts to collect data on individual stream fishes in a number of study areas and in the development of technologies to study fish in the field (e.g. PIT tag antenna design and implementation). Current research focusses on development of integrated population models, forecasting climate change effects, estimating fitness in the wild, and on combining survey-based occupancy models with demographic models.