Red-cockaded Woodpecker
Evaluating the impact of alternative timber management plans on red-cockaded woodpeckers
H. Resit Akçakaya
Applied Biomathematics, 100
North Country Road, Setauket, NY 11733
Jerome A. Jackson
Department of Biological Sciences,
Mississippi State University, Mississippi State, MS 39762-5759
Lev R. Ginzburg
Department of Ecology and Evolution,
Stony Brook University, Stony Brook, NY 11794
Red-cockaded Woodpecker (RCW) is an endangered species that lives in mature pine forests from Florida to Virginia and west to ty southeast Oklahoma and eastern Texas. From the late 1800s to the mid 1900s, the Red-cockaded Woodpecker rapidly declined as its mature pine forest habitat was altered for a variety of uses, primarily timber harvest and agriculture. Our analysis involved assessing the effect of a timber harvest plan on the viability of a RCW population in Louisiana. We used GIS maps to estimate a habitat model. Based on this model, and predicted timber harvest plan, we estimated the change in the habitat suitability and other parameters of this RCW population.
Habitat Dynamics Based on GIS
Data:
We used GIS data (raster maps
exported from GRASS) on the habitat characteristics, such as stand type (i.e,
the dominant tree species), basal area and density of pine species and
hardwoods, and distance from streams. Using these data and the locations of
woodpecker nests, we estimated a habitat model with logistic regression.
We validated the model by estimating the habitat function using only data from one population, and predicting the habitat suitability of the nest locations in another population. We entered the habitat model in RAMAS GIS to create a habitat suitability map (see Figure).
We then simulated a timber management plan to create a series of habitat maps, each showing the distribution of suitable RCW habitat in a particular year. We used RAMAS GIS to calculate the change in the carrying capacity of the habitat as a function of time, based on the simulated plan.
Population dynamics:
In a parallel analysis, we used extensive banding
data to estimate demographic parameters (such as survival, fecundity, and
temporal variability in these rates) of a population model. We combined the
population model with the habitat dynamics model.
This habitat-based metapopulation model is being used to evaluate the impact of forest management practices, such as a planned cut, on the carrying capacities of habitat patches and other parameters of the red-cockaded woodpecker populations inhabiting these patches.
The model will then be run with different management options to compare their impacts in terms of the predicted risk of extinction, or rate of recovery of the metapopulation.
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