March 2012

R5 Science Seminar Series 2012


Date: Thursday, March 8th, 12:00 noon - 1:00 p.m., Northeast Region Office Large Auditorium. This seminar will be broadcast on the internet. You will be able to view the presentation by clicking this link or for closed captioning, please use this link

Title: Patch Metrics, Wild Brook Trout, and the Chesapeake Bay

Presenter: Mark Hudy, National Aquatic Ecologist, USDA Forest Service

Abstract: The wild brook trout resource in the Chesapeake Bay has been significantly reduced over the last 150 years and faces ongoing and future threats from climate change, land use changes, invasive species and loss of genetic integrity (Hudy et al. 2008). Monitoring both short and long term trends on individual brook trout (Salvelinus fontinalis) populations and the resource as a whole are important needs of managers. Past assessments on the 1,443 subwatersheds in the Chesapeake Bay found that 226 had healthy brook trout (intact); 542 had reduced populations and 290 were extirpated (Hudy et al. 2008). However, the subwatershed scale assessment was not fine scale enough to efficiently monitor trends on the ground of interest to many mangers. Standard population estimates using mark-recapture and depletion removal estimates are also not viable for large scale monitoring because of expense, inability to detect trend (i.e. large coefficient in variation), and problems expanding the sample to the entire population. However, fine scale occupancy data (at the catchment level) exist for the majority of the brook trout resource in the Chesapeake Bay. Currently (not counting New York, not completed yet), there are 3,003 catchments containing allopatric brook trout populations; 1,716 catchments containing sympatric populations (with brown or rainbow trout); and 1,966 catchments containing only exotic trout species. We used this fine scale catchment data to identify unique patches of brook trout. We define a "patch" as a group of contiguous catchments occupied by wild brook trout. Patches are not connected physically (separated by a dam, unoccupied warm water habitat, downstream invasive species, etc) and are generally assumed to be genetically isolated. In the Chesapeake Bay there are 868 patches of brook trout habitat with an average patch size of 2,800 ha.

Bio: Mark Hudy is the National Aquatic Ecologist - East at USDA Forest Cervicitis has served on the Eastern Brook Trout Joint Venture (EBTJV) Steering Committee in the past and is currently a member. Mark has been collecting and analyzing data on the wonders of brook trout for the past 30 years, resulting in applied research that has shed light on current and past conservation activities. Hudy received his B.S. in Fisheries from Virginia Tech and his M.S. in Fisheries from Utah State University.

Date: Thursday, March 22, 12:00 noon - 1:00 p.m., Northeast Region Office Large Auditorium. This seminar will be broadcast on the internet. You will be able to view the presentation by clicking this link:

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.

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