Corema conradii (Broom crowberry) is a low-growing subshrub found throughout coastal sandplain heathlands of New England, especially within abandoned or current firing ranges of military bases. Current populations are aging and threatened due to land use change, deer browsing, and afforestation occurring with a lack of frequent fire. Disturbances may cause regeneration of Corema conradii, though the germination requirements of this species have not been tested experimentally. We investigated two potential management practices, fire and soil disturbance, to encourage regeneration of reproductive populations of this species. We conducted an experimental restoration of this species at two sandplain heathland sites at Cape Cod National Seashore, Massachusetts. Our treatments were mechanical disturbance and prescribed burns that occurred either in the spring or summer of 2012, with paired controls. We tested the hypotheses that fire and mechanical disturbance in combination promote higher germination levels of this species than each of those treatments individually, and that fire and disturbance treatments individually would have greater germination rates than the control treatment.
Results/Conclusions
The summer and spring fire treatments resulted in significantly greater rates of germination than the mechanical disturbance treatment, however there were no significant differences in germination between the different fire seasons. The mechanical disturbance treatment alone had the same low rates of germination as the controls. We did not find a synergism between the mechanical disturbance treatment and the fire treatments for germination rates of C. conradii, as we had expected. Rather, germination of this species were higher in those plots that had experienced fire, but had not experienced mechanical disturbance. The overall species diversity of the plots with spring and summer burns were significantly higher than plots that had not experienced burns. Furthermore, the species diversity of undisturbed plots that experienced burns was higher than those plots that were mechanically disturbed, suggesting that human disturbance of the soil inhibits the ability of the natural disturbance of fire to reset the successional trajectory of this habitat.