Dissertation Research: Does the Presence and Spatial Arrangement of Co-flowering Species Affect Threshold Critical Population Densities in Plants?

小种群或稀疏种群的植物可能没有足够的授粉者访问，以产生足够的种子来取代垂死的个体。 因此，低于某一阈值大小或密度的种群可能注定要灭绝。 如果一个共同出现的植物物种共享传粉者，它的存在可能会增加访问和种子生产的植物在稀疏的人口增加当地的花密度。 这可能会降低阈值密度，高于阈值密度的种群会持续存在。 提出的实验将确定条件下，植物物种可以降低或提高阈值人口密度的其他植物物种，使用实验阵列的植物在不同的密度，有和没有共同发生的植物，并测量传粉者的访问，花粉接收的花朵，和数量的水果和种子生产。 实验数据与自然种群中个体的生长和存活数据相结合，将用于种群模型，以确定每种密度和物种处理的种群是否持续存在。 该项目将告知生态学家和自然资源保护主义者，在其他物种存在的情况下，小种群或稀疏种群是否更有可能持续存在。 此外，该项目还将为在恢复地区重建本土植物种群的土地管理人员提供信息。

Plants in small or sparse populations may receive insufficient pollinator visits to produce enough seeds to replace dying individuals. Thus, populations below some threshold size or density may be doomed to extinction. If a co-occurring plant species shares pollinators, its presence may increase both visitation and seed production of plants in sparse populations by increasing local flower density. This may lower the threshold density above which populations persist. Experiments proposed will determine conditions under which plant species can lower or raise threshold population densities of other plant species, using experimental arrays of plants at different densities, with and without co-occurring plants, and measuring pollinator visitation, pollen receipt by flowers, and the numbers of fruits and seeds produced. Experimental data, combined with data on growth and survival of individuals in natural populations, will be used in population models to determine whether populations of each density and species treatment persist.Plant populations will likely become smaller and sparser as the landscape becomes more fragmented and degraded. This project will inform ecologists and conservationists about whether small or sparse populations are more likely to persist in the presence of other species. Also, this project will inform land managers working to re-establish populations of native plants in restored areas.