Dissertation Research: Interspecific Interactions in Stage Structured Population Models: The Effects of Herbivores and Pollinators on Trillium grandiflorum

阶段结构种群模型中的种间相互作用：草食动物和传粉者对大花梗的影响植物种群的生长速度取决于其与草食动物和传粉者相互作用的强度，以及这些相互作用发生在植物生命周期中的阶段。因此，植物种群之间与食草动物和传粉者相互作用程度的变化可能导致自然植物种群之间生长速率的变化。如果有高密度开花植物的种群对食草动物和传粉者都更有吸引力，那么它们与食草动物和传粉者的相互作用的大小可能会随着植物种群的增长或减少而发生决定性的变化。我收集了一种多年生森林草本植物Trillium grandflorum的12个种群的初步数据。其与哺乳食草动物白尾鹿和昆虫传粉者大黄蜂的相互作用程度在这些种群中差异很大，这些相互作用主要影响植物生命周期的生殖阶段。在一项控制植物密度的试点实验中，发现植物-食草动物和植物-传粉者相互作用的幅度发生了显著变化。在这项工作中，我将量化由食草动物和传粉者相互作用的变化引起的种群之间的数量变化。此外，在几个种群中，我将通过实验操纵植物密度，以更充分地量化草食动物和传粉者对万里草存活、生长和繁殖力的密度依赖影响。我将使用一个建模框架来综合所有这些信息，并评估种间相互作用变化对植物种群生长率的影响。

Proposal 0105000DIG: Interspecific interactions in stage structured population models: The effects of herbivores and pollinators on Trillium grandiflorumSusan Kalisz , Tiffany KnightThe growth rate of a plant population depends on the strength of its interactions with herbivores and pollinators, as well as the stage in the plant life-cycle in which these interactions take place. Thus, variation in the magnitude of interactions with herbivores and pollinators among plant populations can cause variation in the rates of growth among natural plant populations. If populations that have a high density of flowering plants are more attractive to both herbivores and pollinators, then the magnitude of their interactions with both herbivores and pollinators may be expected to change deterministically as plant populations grow or decline in time. I have collected preliminary data on 12 populations of Trillium grandiflorum, a perennial forest herb. The magnitude of its interactions with its mammalian herbivore, white tailed deer, and insect pollinator, bumblebees, vary highly among these populations, and these interactions primarily influence the reproductive stage in the plant life-cycle. In a pilot experiment that manipulated plant density, significant changes in the magnitude of both plant-herbivore and plant-pollinator interactions were found. In this proposed work, I will quantify the amount variation among populations that is caused by variation in herbivore and pollinator interactions. In addition, among several populations, I will experimentally manipulate the plant density to more fully quantify the density-dependent influences of herbivores and pollinators on Trillium survival, growth and fecundity. I will use a modeling framework to synthesize all of this information and assess the effects of changes in interspecific interactions on the growth rate of plant populations.