Modeling controlled burning and trampling reduction for conservation of Hudsonia montana

Populations of mountain golden heather (Hudsonia montana), a threatened North Carolina shrub, are declining due to the suppression of natural fires and increased trampling by hikers and campers. Consequently, proposed management strategies have focused on conducting controlled burns and restricting human traffic. To help design an optimal management plan, we used demographic data from a 5-year field study of H. montana-which included a controlled burn-to construct size-based population projection matrices. Using these matrices, we projected the consequences of instituting controlled burns and hiking and camping restrictions separately and in tandem. We also determined the burn frequency that would maximize H. montana's population growth rate. Finally, we used a stochastic model to determine how environmental fluctuations could alter the efficacy of conservation measures. Our results suggest that, although neither burning nor trampling reduction alone can reverse H. montana's decline, a judicious combination of the two has an excellent chance 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 increased to 12-16 years without significantly jeopardizing the success of the management plan. Our results show that, even with the limited data available, size-based projection matrix models can be useful tools for identifying promising combinations of multiple management strategies for most threatened plants.

Duke Scholars

Author William F. Morris Biology