The Role of Keystone Herbivores in Regulating Ecosystem Function: An Experimental Approach Using Long-Term Herbivore Removals

摘要/ abstract摘要：本文研究了两种主要食虫动物对小松松柏林地生态系统功能的影响。针蚧虫使幼松落叶，而钻茎蛾则杀死成熟树木的嫩枝。这些草食动物的影响具有区域广泛性，并且似乎与环境压力呈正相关。利用两个长期的除蛾和除鳞实验（分别为15年和13年），我们建议在三种类型的试验田中研究草食对生态系统的影响：1)被蛾或蚧虫侵染的易感树木，2)每年至少清除这些草食动物13年的易感树木，3)对蛾或鳞有天然抗性的树木。通过比较有和没有慢性草食的树木/土壤系统，我们可以更好地了解草食动物如何影响美国西南部主要植被类型松树-杜松林地的生产力和养分循环。

ABSTRACT9816001KochThe Role of Keystone Herbivores in Regulating Ecosystem Function: An Experimental Approach Using Long-Term Herbivore RemovalsThis study examines how two major insect herbivores impact pinyon pine-juniper woodlands. The pinyon needle scale insect defoliates juvenile pines while the stem-boring moth kills shoots of mature trees. The impact of these herbivores is regionally extensive and appears to be positively correlated with environmental stress. Taking advantage of two long-term moth and scale removal experiments (15 and 13 years, respectively) we propose to examine the ecosystem effects of herbivory in experimental plots with three classes of trees, 1) susceptible trees infested with moth or scale insects, 2) susceptible trees from which these herbivores have been removed annually for at lease 13 years and 3) trees that are naturally resistant to moth or scales. By comparing tree/soil systems with and without chronic herbivory, we can better understand how herbivores affect productivity and nutrient cycling in pinyon-juniper woodlands, a major vegetation type of the southwestern United States.