Laidig, K. J. and R. A. Zampella. 1999. Community attributes of Atlantic white cedar (Chamaecyparis thyoides) swamps in disturbed and undisturbed Pinelands watersheds. Wetlands 19:35-49. (Summary)
In this study, we examined the relationship of regional watershed conditions to plant species composition and richness, the occurrence of plant species with different biogeographic and wetland affinities, cedar reproduction, and environmental conditions in Atlantic white cedar (Chamaecyparis thyoides) swamps of the New Jersey Pinelands (Pine Barrens). These attributes were evaluated with respect to high, moderate, and low watershed disturbance, defined as the percentage of combined developed and agricultural land cover in a basin. High watershed disturbance was associated with elevated pH, specific conductance, and nutrient concentrations in streams adjacent to our cedar swamp study sites. Cedar swamps in the high-disturbance class generally had fewer understory plant species and differed from other sites in overall understory species composition. Only one plant considered uncharacteristic of the Pinelands was associated with high-disturbance sites, and exotic plants (plants not native to New Jersey) were absent at all sites. Unlike previous, similar studies in the Pinelands, the high-disturbance sites did not support a unique group of plants. Although Sphagnum moss cover, which is an indication of optimal cedar seedbed conditions, was lowest in disturbed-basin swamps, there were no significant differences in overall seedbed conditions and cedar seedling density between the three disturbance classes. High-disturbance swamps contained more red maple (Acer rubrum) in the canopy. Because other environmental variables did not differ significantly between disturbance types and red maple is a common associate of cedar throughout the Pinelands, we suggested that differences in species composition and richness may be related to canopy conditions and regional differences in biogeography rather than the effects of watershed disturbance. We concluded that cedar swamps located a distance from upgradient watershed disturbances and not affected by overbank flooding from the adjacent stream seem to be buffered from the impacts of regional land-use disturbances.