Evaluating Effects of Historic Agriculture and Current Restoration Activity on Succession and Plant Diversity in the New Jersey Pine Barrens

Restoration Notes have been a distinguishing feature of Ecological Restoration for more than 25 years. This section is geared toward introducing innovative research, tools, technologies, programs, and ideas, as well as providing short-term research results and updates on ongoing efforts. Please direct submissions and inquiries to the editorial staff (ERjournal@aesop.rutgers.edu).

The New Jersey Pine Barrens consists of 400,000 hectares of upland, aquatic, and wetland habitats with sandy, acidic soils (Good and Good 1984, Forman 1998). The area played an important role in New Jersey’s agricultural history, with cranberry (Vaccinium macrocarpon) as one of the state’s staple crops (Procopio 2010, Wen 2010). In the late-1800s and early-1900s, Atlantic white-cedar (Chamaecyparis thyoides) and red maple (Acer rubrum) swamps were often converted into cranberry bogs. Initially, there was little soil alteration because agricultural areas were within floodplains and hydric soils were present. In the mid- to late-1900s, the process of “modernizing” cranberry bogs allowed expansion onto higher elevations including upland and wetland areas on the edges of floodplains. Sites were intensively managed with deep ditches, drains, perforated pipes, and diesel pumps that obtained water from aquifers during droughts. Sand overlaying the organic horizon of wetland soil was leveled to ensure even drainage and compacted to allow heavy equipment access. A new layer of sand was added every few years to bury cuttings and stimulate crop production (Eck 1990, Wen 2010).

There is substantial interest of restoring swamps on retired agricultural sites in the Pine Barrens (Mylecrane et al. 2004). In 2003, the New Jersey Conservation Foundation (NJCF) acquired the title to the Franklin Parker Preserve (FPP): 3,800 ha of forests, swamps, and bogs formerly owned by the AR DeMarco Cranberry Company (39.772444, −74.529383). This area is within the village of Chatsworth (Burlington County, NJ, US). Aerial photographs from 1930 show patches of cranberry bogs within a matrix of swamps prior to modernization (Reiser 2014). Starting in the 1960s, over 405 ha of this area was converted into modernized cranberry bogs, with the last harvest in 2001.

In 2004, with funds from the United States Department of Agriculture Natural Resource Conservation Service’s (USDA NRCS) Wetlands Reserve Program, NJCF began restoring 445 ha of the FPP that were altered by agriculture, encompassing land that was modernized as well as bogs that were less intensively managed. In modernized bogs, restoration included plugging unnatural bypass ditches and drains and returning the original stream flow onto historic floodplains. The NJCF overturned compacted soil to create mounds and expose hydric soil buried beneath the sand. In older, peat-based cranberry bogs that had not been modernized, hydric soil was still at the surface and natural succession was occurring. Therefore, recontouring terrain was unnecessary. The restoration goal was to “deconstruct” agricultural modifications to hydrology so that tributaries could passively return to, and flow across agriculturally modified floodplains throughout the site. As of 2012, most of the 445-ha restored area had reestablished a natural hydrologic regime. In 2013, the wetland experienced its first full growing season under a naturally fluctuating stream corridor hydrology since it was intensively managed.

This study presents pilot research investigating effects of restoration efforts on species recruitment to a 32-ha subsection where hydrologic function was restored by early 2010. Our objectives were twofold: 1) to monitor preliminary effects of restoration activities on species recruitment, and 2) to document vegetative structure that exists within bogs that were modernized versus those that were not modernized. Plant diversity, coverage, tree recruitment, and hydric soil conditions were used as indicators of recovery.

This study focused on three habitats within the FPP: 1) a modernized bog undergoing restoration, 2) a peat-based bog in early succession, and 3) a modernized bog without restoration (control). Nine years after cranberry agriculture ceased, in 2010, we established four 100-m² (10 m × 10 m) plots within each environment, except on the modernized bog control site where its size limited us [End Page...