Modeling controlled burning and trampling reduction for conservation of Hudsonia montana

Populations of mountain golden heather (Hudsonia montana), a threatened Nor th Carolina shrub, are declining due to the suppression of natural fires an d increased trampling by hikers and campers. Consequently, proposed managem ent strategies have focused on conducting controlled burns and restricting human traffic To help design an optimal management plan, we used demographi c data from a 5-year field study Of H. montana-which included a controlled burn-to construct size-based population projection matrices Using these mat rices, we projected the consequences of instituting controlled burns and hi king and camping restrictions separately and in tandem. We also determined the burn frequency that would maximise H. montana's population growth rate. Finally, we used a stochastic model to determine how environmental fluctua tions could alter the efficacy of conservation measures. Our results sugges t that, although neither burning nor trampling reduction alone can reverse H. montana's decline, a judicious combination of the two has an excellent c hance of doing so. A burn frequency of once every 6-8 years should maximize H. montana's population growth, although the interburn interval could be i ncreased to 12-16 years without significantly jeopardizing the success of t he management plan. Our results show that even with the limited data availa ble, size-based projection matrix models can be useful tools for identifyin g promising combinations of multiple management strategies for most threate ned plants.