Sullivan Lauren L, Danielson Brent J, Harpole W Stanley
Department of Ecology Evolution and Behavior, University of Minnesota, St. Paul, Minnesota, 55108, United States of America.
Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa, 50011, United States of America.
PLoS One. 2016 Feb 5;11(2):e0147715. doi: 10.1371/journal.pone.0147715. eCollection 2016.
Plant-herbivore interactions influence the establishment context of plant species, as herbivores alter the community context in which individual species establish, and the spatial relationship between individuals and their source population as plants invade. This relationship can be described using an establishment kernel, which takes into account movement through seed dispersal, and subsequent establishment of adults. Mammalian herbivores are hypothesized to influence plant population growth and establishment through a combination of consumption of seeds and seedlings, and movement of seeds. While the movement abilities of plants are well known, we have very few empirical mechanistic tests of how biotic factors like mammalian herbivores influence this spread potential. As herbivores of all sizes are abundant on the landscape, we asked the question, how do mammalian herbivores influence the population growth, spatial establishment, and the community establishment context of an early-recruiting native prairie legume, Chamaecrista fasciculata? We planted C. fasciculata in source populations within a four-acre tallgrass prairie restoration in plots with and without herbivores, and monitored its establishment with respect to distance from the source populations. We found that herbivores decreased population growth, and decreased the mean and range establishment distance. Additionally, C. fasciculata established more often without herbivores, and when surrounded by weedy, annual species. Our results provide insight into how the interactions between plants and herbivores can alter the spatial dynamics of developing plant communities, which is vital for colonization and range spread with fragmentation and climate change. Mammalian herbivores have the potential to both slow rates of establishment, but also determine the types of plant communities that surround invading species. Therefore, it is essential to consider the herbivore community when attempting to restore functioning plant communities.
植物与食草动物的相互作用会影响植物物种的建立环境，因为食草动物会改变个体物种建立所处的群落环境，以及植物入侵时个体与其源种群之间的空间关系。这种关系可以用一个建立核来描述，它考虑了通过种子传播的移动以及随后成年植株的建立。据推测，哺乳动物食草动物会通过种子和幼苗的消耗以及种子的移动，来影响植物种群的增长和建立。虽然植物的移动能力是众所周知的，但对于像哺乳动物食草动物这样的生物因素如何影响这种传播潜力，我们几乎没有实证性的机制测试。由于各种体型的食草动物在景观中数量众多，我们提出了一个问题：哺乳动物食草动物如何影响一种早期招募的本地草原豆科植物——束花山蚂蝗（Chamaecrista fasciculata）的种群增长、空间建立以及群落建立环境？我们在一片四英亩高草草原恢复区的源种群中，在有食草动物和没有食草动物的地块上种植了束花山蚂蝗，并监测其相对于源种群的距离的建立情况。我们发现，食草动物降低了种群增长，并减小了平均建立距离和建立距离范围。此外，束花山蚂蝗在没有食草动物且被杂草类一年生植物包围的情况下更常建立。我们的结果为植物与食草动物之间的相互作用如何改变发育中植物群落的空间动态提供了见解，这对于在破碎化和气候变化情况下的殖民化和范围扩展至关重要。哺乳动物食草动物有可能既减缓建立速度，又决定入侵物种周围植物群落的类型。因此，在尝试恢复功能正常的植物群落时，考虑食草动物群落至关重要。
