The habitat use by birds and anurans of active and abandoned cranberry farms in the Pine Barrens of New Jersey

Active cranberry farms currently cover 3,600 acres in the riverine wetland areas of the New Jersey Pine Barrens, and many more acres of abandoned farms, deserted during the region’s 150 year tradition of cranberry cultivation, dot the landscape. Both active and abandoned farms are used by various animal communities. However, the community composition and animals’ habitat use is different among active farms and different ages of abandoned farms. Since fall 2004, I monitored the distribution of bird and anuran species in active and abandoned cranberry farms. Bird transect surveys were conducted in three active and one abandoned farms. Each farm was surveyed one to four times a month throughout the year. Anurans were surveyed in two active farms and two abandoned farms (abandoned for five and fifty years, respectively), by identifying their calls and estimating their densities. The result shows bird distributions are determined by different factors in active and abandoned sites. In active sites, their seasonal density varies according to the vegetation type along the transects (MANOVA, Wilk’s λ=0.014), while in abandoned sites, density is determined by the location in the landscape (MANOVA, Wilk’s λ=0.0382). In contrast to bird species, anurans’ limited dispersal ability and sensitivity to water quality drives distributional patterns. The spring peeper, green frog, and carpenter frog were found in all sites; the endangered Pine Barrens treefrog, a water quality sensitive species, was only in abandoned sites; Fowler’s toad, a species that is atypical of the acidic wetland conditions of the Pine Barrens, were only heard in active farms.  Understanding how water quality, vegetation, and hydrology drive bird and anuran distributions will provide important information to inform agricultural management in active farms, as well to increase the efficiency of restoring abandoned farms.