Spiller David A, Schoener Thomas W
Section of Evolution and Ecology and Center for Population Biology, One Shields Avenue, University of California, Davis, California 95616-8755, USA.
Ecology. 2007 Jan;88(1):37-41. doi: 10.1890/0012-9658(2007)88[37:aoifdf]2.0.co;2.
Major abiotic disturbance can be an important factor influencing food-web dynamics, particularly in areas impacted by the recent increase in hurricane activity. We present a unique set of data on key food-web processes occurring on 10 small islands for three relatively calm years and then four subsequent years during which two hurricanes passed directly over the study site. Herbivory, as measured by leaf damage, was 3.2 times higher in the year after the first hurricane (2000) than in the previous year and was 1.7 times higher in the year after the second hurricane (2002) than in 2001. The effect of a top predator (the lizard, Anolis sagrei) on herbivory strengthened continuously after the first hurricane and overall was 2.4 times stronger during the disturbance period than before. Overall abundance of lizards was 30% lower during the disturbance period than before, and abundances of web spiders and hymenopteran parasitoids were 66% and 59% lower, respectively. We suggest that increased herbivory observed on all islands was caused, at least in part, by the overall reduction in predation by both lizards and arthropods, whereas magnification of the lizard effect on herbivory was caused by reduced compensatory predation by arthropods.
重大非生物干扰可能是影响食物网动态的一个重要因素，尤其是在受近期飓风活动增加影响的地区。我们展示了一组独特的数据，这些数据记录了10个小岛上在相对平静的三年以及随后四年（期间有两场飓风直接经过研究地点）中发生的关键食物网过程。以叶片损伤衡量的食草率在第一场飓风过后的年份（2000年）比前一年高出3.2倍，在第二场飓风过后的年份（2002年）比2001年高出1.7倍。顶级捕食者（蜥蜴，安乐蜥）对食草作用的影响在第一场飓风过后持续增强，在干扰期间总体上比之前强2.4倍。在干扰期间，蜥蜴的总体数量比之前低30%，结网蜘蛛和膜翅目寄生蜂的数量分别比之前低66%和59%。我们认为，在所有岛屿上观察到的食草增加至少部分是由蜥蜴和节肢动物捕食的总体减少导致的，而蜥蜴对食草作用的放大效应是由节肢动物补偿性捕食的减少引起的。
