Dissertation Research: The Influence of Herbivory and Compensatory Regrowth on the Demography of Long-Lived Plants

最近，关于陆生植物“补偿”食草动物损害的能力一直存在相当大的争议。如果植物能有效补偿食草动物造成的组织损失，那么这种损害对植物种群动态的影响应该很小。虽然一些研究已经关注了食草动物对半开花（只开一次花）植物的影响，但很少有研究关注食草动物对无开花（每年开花）物种终生后代生产的影响。一项实验将在阿拉斯加的Wrangell山脉进行，研究慢性鳞翅目（扁桃科）取食对矮火草（一种长寿的多年生草本植物）生长、种子产量和幼苗质量的影响。植物将在三年内遭受三种强度的人为破坏，为构建生长和种子产量的概率转移矩阵提供数据。这些模型可以用来估计不同频率和强度的草食对火杂草30 - 40年寿命内植物性能的影响。为了估计再生在减轻草食影响中的重要性，将进行一项控制损害后补偿性再生的实验。这项工作将提供一个对食草对一种无脊椎植物的终生影响的为数不多的估计。

There has recently been considerable controversy over the ability of terrestrial plants to "compensate" for herbivore damage. If plants can effectively compensate for the tissue removal caused by herbivores, damage should have little influence on the population dynamics of plant species. Although several studies have looked at the influence of herbivory on semelparous (Flower only once) plants, little research has addressed the impact of herbivores on the lifetime offspring production of iteroparous (Flowering every year) species. An experiment will be performed in the Wrangell Mountains of Alaska examining the influence of chronic lepidopteran (Tortricidae) feeding on the growth, seed production, and seedling quality of dwarf fireweed, Epilobium latifolium, a long-lived herbaceous perennial. Plants will be subjected to three intensities of artificial damage over three years, giving data to construct probability transition matrices for growth and seed output. These models can then be used to estimate the influence of different frequencies and intensities of herbivory on plant performance over the thirty to forty year life-span of fireweed. An experiment in which compensatory regrowth following damage is controlled, in order to estimate the importance of regrowth in mitigating the impact of herbivory will be performed. This work will give one of the few estimates of the life-time impacts of herbivory on an iteroparous plant species.