Background

Coastal-plain ponds are a distinct feature in the New Jersey Pinelands. Because these wetlands are hydrologically connected to local groundwater sources, act as biogeochemical processing systems, and are necessary for the maintenance of regional plant and animal diversity, ponds serve important ecological functions. Like natural ponds, created wetlands can also provide important habitats for wetland-dependent plants and animals, especially in human-dominated landscapes where natural wetlands may have been altered or eliminated. Two types of created wetlands commonly found in the Pinelands are shallow excavations that intercept the groundwater (i.e., excavated ponds) and excavations designed to receive runoff (i.e., stormwater basins).

In 2012 and 2013, the Pinelands Commission obtained EPA funding to study natural ponds, excavated ponds, and stormwater basins in the Pinelands. A summary of the study is below. As a component of the study, scientists from the Commission and the U.S. Geological Survey New Jersey Water Science Center collaborated to investigate differences in current-use pesticides and emerging-amphibian pathogens between the three wetland types. (USGS study)

(click on the report cover to open)

Summary

We identified and mapped 5,850 natural ponds, excavated ponds, and stormwater basins in the Pinelands Area. We assessed the vulnerability of natural and excavated ponds to developed land by simulating a buildout scenario and assessing changes in surrounding developed land, the percentage of non-native plant species, and pH for each pond. Natural ponds were less vulnerable than excavated ponds to future developed land because most natural ponds were located in protected areas of the Pinelands.

We also assessed off-road vehicle damage at natural and excavated ponds and found that ponds that were larger, with greater amounts of open water and herbaceous vegetation cover, near other damaged ponds, and closer to sand or paved roads tended to be damaged by off-road vehicles more often than smaller ponds with greater shrub and tree cover that were either located in developed or farmed landscapes or in less accessible and remote areas of the forest. A greater percentage of excavated ponds were damaged by off-road vehicles compared to natural ponds.

In a small subset of natural ponds, we explored whether or not dragonfly and damselfly species varied with surrounding land-use conditions. Our results showed that these species may be more influenced by forest canopy cover and wetland size rather than surrounding land use, but additional research is needed to fully determine if land use plays a major role in shaping the composition of these species groups in natural ponds or in other types of Pinelands wetlands.

Lastly, we compared 39 environmental and biological variables between natural ponds, excavated ponds, and stormwater basins. Our results showed that both natural and excavated ponds can exhibit high ecological integrity, display characteristic Pinelands water-quality conditions, and support native assemblages of plants and animals, whereas water-quality conditions in stormwater basins are degraded and basins are a major source of non-native and introduced species.

Citation

Bunnell, J.F., K.J. Laidig, P.M. Burritt, and M.C. Sobel. 2018. Vulnerability and comparability of natural and created wetlands. Final report to the U.S. Environmental Protection Agency, Pinelands Commission, New Lisbon, New Jersey, USA.