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New Lisbon, NJ, United States

The purpose of this study was to estimate changes to aquatic habitat availability and fish and aquatic macroinvertebrate assemblages in coastal plain streams that may result from groundwater withdrawals. Hypothetical streamflow reductions of 5, 10, 20, and 30% of average annual streamflow and the 7-day low flow were calculated for 14 study sites. Using study-site streamflow and channel morphology data, relationships were developed to estimate five physical habitat metrics including average stream width, stream depth, stream cross-sectional area, stream-reach volume, and stream velocity. A second set of relationships was then developed to estimate the percentage reduction to each habitat metric under the hypothetical streamflow reduction scenarios. The average percentage decrease and variability of each habitat metric increased with successive streamflow reductions. Average percentage decreases in stream width, stream depth, stream cross-sectional area, and stream-reach volume were more pronounced for the reductions of average flow, whereas the average percentage decreases in stream velocity were more pronounced for the reductions of low flow. Models derived from a separate fish and macroinvertebrate study were used to estimate assemblage structure responses based on hypothetical reductions in average annual streamflow. The results of this study can be used to estimate the potential impact of groundwater withdrawals and subsequent streamflow reductions on available aquatic habitat and changes to fish and macroinvertebrate assemblages in coastal plain streams. © 2011 John Wiley & Sons, Ltd.

Laidig K.J.,Pinelands Commission | Zampella R.A.,Pinelands Commission | Brown A.M.,Pinelands Commission | Procopio N.A.,Pinelands Commission
Wetlands | Year: 2010

We developed vegetation models that, when linked to groundwater-hydrology models and landscape-level applications, can be used to predict the potential effect of groundwater-level declines on the distribution of wetland-forest communities, individual wetland species, and wetland-indicator groups. An upland-to-wetland vegetation gradient, comprising 201 forest plots located in five different study basins and classified as either upland pine-oak, pitch pine lowland, pine-hardwood lowland, hardwood swamp, or cedar swamp, paralleled variations in water-level. Water levels, woody-species composition, the percentage of wetland- and upland-indicator species, and soil properties varied among the five vegetation types. Because of the functional relationship of hydrology with its correlated soil variables, hydrology represented a good proxy for the complex hydrologic-edaphic gradient associated with the upland-to-wetland vegetation gradient. Two types of vegetation models were developed to predict potential changes in vegetation associated with water-level declines. Logistic regression models predicted the probability of encountering the different vegetation types and 29 community-indicator species in relation to water level. Simple regression models predicted the relative abundance and richness of wetland-and upland-indicator species as a function of water level. © 2010 Society of Wetland Scientists.

Zampella R.A.,Pinelands Commission | Bunnell J.F.,Pinelands Commission | Laidig K.J.,Pinelands Commission | Procopio III N.A.,Pinelands Commission
Ecological Indicators | Year: 2010

The establishment of introduced species in aquatic and wetland habitats is often associated with human-related environmental degradation. In the blackwater streams of the New Jersey Pinelands, the presence of nonnative species drives the relationship between community composition and watershed disturbance associated with developed land and upland agriculture. Most Pinelands lakes are shallow, artificial stream impoundments. In this study, we determined if land-use gradients or thresholds were associated with the presence of nonnative-herbaceous-plant, woody-plant, fish, and anuran species in 30 Pinelands stream impoundments. Correlation and regression analyses indicated that the response of all four taxonomic groups to watershed disturbance was an increase in the number of nonnative species and the proportion of total species richness represented by nonnative species. Native-anuran richness decreased along the watershed-disturbance gradient. We found both linear and nonlinear responses when relating species-richness attributes to the percentage of altered land (combined percentage of upland agriculture and developed land) in the associated watersheds, but the nonlinear responses cannot be considered land-use-related degradation-threshold responses. The breaks in the regression lines describing the relationship between the percentage of total species richness represented by nonnative plants and fish and altered land in our Pinelands watersheds did not represent a degradation threshold because, with the exception of the percentage of total species richness represented by nonnative-anuran species, a progressive decline in aquatic integrity was observed before the break points. Kruskal-Wallis ANOVA revealed significant differences in species-richness attributes only among stream impoundments with contrasting altered-land profiles, providing further evidence that aquatic degradation was progressive. Logistic regression identified the point along the watershed-disturbance gradient at which the probability of encountering nonnative bullfrogs was greater than that for native carpenter frogs. © 2009 Elsevier Ltd. All rights reserved.

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