Roland Jens
Ontario Region, Forestry Canada, 1219 Queen St. East, Sault Ste. Marie, Ontario, Canada.
Department of Zoology, University of Alberta, T6G 2E9, Edmonton, Alberta, Canada.
Oecologia. 1993 Feb;93(1):25-30. doi: 10.1007/BF00321186.
I examined historical data (1950-1984) on the duration of outbreaks of the forest tent caterpillar (Malacosoma disstria) in northern Ontario, Canada. Outbreak duration was compared to host tree species dominance and forest structure over large areas of boreal forest partially cleared for agriculture. Abundance of the principal host tree species Populus tremuloides had no consistent effect on duration of outbreak within forest districts, and was negatively correlated with duration of outbreaks among the eight forest districts examined. The amount of forest edge per km was the best, and most consistent, predictor of the duration of tent caterpillar outbreaks both within individual forest districts and among forest districts. Because forest tent caterpillar populations are driven largely by the impact of parasitoids and pathogens, results here suggest that large-scale increase in forest fragmentation affects the interaction between these natural enemies and forest tent caterpillar. Increased clearing and fragmentation of boreal forests, by agriculture and forestry, may be exacerbating outbreaks of this forest defoliator.
我研究了加拿大安大略省北部森林天幕毛虫（Malacosoma disstria）爆发持续时间的历史数据（1950 - 1984年）。将爆发持续时间与大面积因农业用途而部分砍伐的北方森林中的寄主树种优势度和森林结构进行了比较。主要寄主树种颤杨的丰度对林区内爆发持续时间没有一致影响，并且在所研究的八个林区中，它与爆发持续时间呈负相关。每公里森林边缘的数量是单个林区内以及林区之间天幕毛虫爆发持续时间的最佳且最一致的预测指标。由于森林天幕毛虫种群主要受寄生蜂和病原体的影响，这里的结果表明森林破碎化的大规模增加影响了这些天敌与森林天幕毛虫之间的相互作用。农业和林业导致北方森林的砍伐和破碎化加剧，可能正在加剧这种森林食叶害虫的爆发。
