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Assessing the Wildlife Habitat Value of New England Salt Marshes: I. Model and Application
Citation:
MCKINNEY, R. A., M. A. CHARPENTIER, AND C. WIGAND. Assessing the Wildlife Habitat Value of New England Salt Marshes: I. Model and Application. ENVIRONMENTAL MONITORING AND ASSESSMENT. Springer, New York, NY, 154(1-4):29-40, (2009).
Impact/Purpose:
This paper describes an assessment model to quantify the wildlife habitat value of New England salt marshes based on marsh characteristics and the presence of habitat types that influence habitat use by terrestrial wildlife. Wetland assessments currently used by federal, state, and local agencies generally do not focus on quantifying wetland function. Our assessment model specifically targets the wildlife habitat value, one of many important functions and services of coastal marshes. Almost all state and local wetlands regulations include habitat protection goals; of particular interest is whether particular wetlands or classes of wetlands provide habitat for threatened and endangered species. Additionally, wetland protection or restoration goals based on wildlife habitat targets are generally well received and understood by the public, particularly when the species of interest include large charismatic birds and mammals. Our assessment can be used to generate data on wildlife habitat value to supplement comprehensive assessments when assessing areas for which habitat value is of particular importance or concern.
Description:
We developed an assessment model to quantify the wildlife habitat value of New England salt marshes based on marsh characteristics and the presence of habitat types that influence habitat use by terrestrial wildlife. Applying the model to12 salt marshes located in Narragansett Bay, RI resulted in assessment scores that ranged over a factor of 1.5 from lowest to highest. Pre-classifying the results based on marsh size and morphology helped to compare assessment scores between marshes, and demonstrated that even the lower ranking marshes had substantial habitat value. Stepwise multiple regression analysis of assessment scores and model components demonstrated that salt marsh morphology, the degree of anthropogenic modification, and salt marsh vegetative heterogeneity were significant variables and accounted for 91.3% of the variability in component scores. Our results suggest that targeting these components for restoration may lead to improved assessment scores for our study marshes. We also examined the use of lower resolution remote sensing data in the assessment in order to minimize the time and effort required to complete the model. Scores obtained using smaller-scale, lower resolution data were significantly lower than those obtained using larger-scale, higher resolution data (df = 11; t = 2.2; p < 0.001). The difference was significantly positively correlated with the portion of the assessment score that could be attributed to trees, pools, and pannes and marsh size (r2 = 0.50, F = 4.6, p = 0.04), and could indicate a bias against smaller, more heterogeneous marshes. We conclude that potential differences need to be weighed against the time benefit of using this type of data, bearing in mind the marsh size and the goals of the assessment. Overall, our assessment can provide information to aid in prioritizing marshes for protection and restoration, identify marshes that may harbor significant biodiversity, or help monitor changes in habitat value over time.