Microhabitat Relationships of the Endangered Hemiparasite Schwalbea americana (American Chaffseed) in the New Jersey Pine Barrens

Abstract - We conducted observational and experimental studies of the endangered hemiparasitic plant species Schwalbea americana (American Chaffseed, hereafter Schwalbea) in the New Jersey pine barrens to better understand its association with fine-scale environmental conditions. Spatial analyses of Schwalbea coordinates revealed a clustered distribution and analyses of environmental variables found clear associations of Schwalbea clusters with various soil, water, and plant community conditions, including several grass and composite (Asteraceae) species, especially Chrysopsis mariana (Maryland Golden-aster) and Schizachyrium scoparium (Little Bluestem). Subsequent experiments found soil from adjacent areas completely inhibited Schwalbea germination, and greater growth and survival occurred when planted with composites than with grass or woody host species. These factors appeared to explain the failures of past propagation and restoration efforts, which did not reflect these microhabitat preferences.