| Urbanization is a major cause of wetland loss and degradation in the United States. In the New Jersey Pinelands, suburban development is common on uplands adjacent to forested wetlands, and the uplands are coupled to the wetlands by a shallow aquifer in unconsolidated sandy sediments. Engineering features associated with upland suburban development alter the hydrology and water chemistry of the adjacent wetlands, and these abiotic alterations influence the biotic characteristics of the wetlands.; Pinelands swamps dominated by Atlantic white cedar, Chamaecyparis thyoides (L.) BSP., along a gradient of suburban development defined by the successive addition of engineering features (roads, septic systems, and storm sewers), were monitored for hydrology, water chemistry, vascular plant species composition, community structure, cedar growth and reproduction, and the concentration of nutrients and heavy metals in plant tissues.; Septic systems and especially storm sewers increased the concentration of nitrogen, phosphorus, chloride, lead, and zinc in wetland ground and surface water. Dams and channelized streams eliminated the normal fluctuation of the water table. Wetland drainage ditches lowered the water table. Along the gradient of increasing suburban development indigenous Pinelands cedar swamp species were lost; upland, non-Pineland, and exotic species invaded; Sphagnum cover and total plant cover decreased; cedar seedling density decreased; and the concentration of nutrients and heavy metals in plant tissues increased.; Changes in the hydrological regime and in water chemistry interacted to produce the observed changes in the biotic characteristics. However, water chemistry, especially when altered by storm sewers, had a greater impact on Pinelands cedar swamps than did the hydrological regime.; All Pinelands wetlands are protected by a management plan that recognizes the relationship between hydrology, water quality and wetland community structure. This research provides (1) support for the land-use controls implemented by the Pinelands Commission; (2) a quantitative assessment of the impact of specific engineering features; and (3) a quantitative basis for proposing additional numerical water quality standards. |
