Dissertation Research: When Does Propagule Limitation Matter? Interactions Between Propogule Supply and Other Constraints on the Distribution of a Native Annual Forb

繁殖体或种子限制是一个鲜为人知的因素，它可能在决定入侵草原中本土植物物种的分布方面发挥重要作用。 物种的分布通常被认为是由非生物因素（如土壤和气候）和生物因素（如竞争对手，捕食者和种子库动态）控制的。 然而，种子限制是一个额外的限制物种分布，这是知之甚少。 迷人的本地野花天空羽扇豆，Lupinus nanus，是一个很好的模式物种，因为它有几个属性暗示种子限制，它是在广泛的草原栖息地发现。 通过在加州麦克劳克林自然保护区的大规模调查和草地实地实验，我们将具体确定种子的可用性如何与竞争和土壤特性相互作用，以描绘天空羽扇豆在多个尺度上的分布。这项工作具有实际意义的草原恢复，因为它将使我们能够确定的特点，在该网站中，种子添加可能导致在草原化的天空羽扇豆，并可能更丰富和多样的本地植物群落。 鉴于现有资源有限，恢复工作应侧重于最有可能以最少的投资建立长期可生存种群的地区，在这些地区，本地物种的缺乏主要是种子有限的作用。 从我们的实验中，原生植物再入侵的方法将被开发，考虑到相互作用的机制限制原生植物的分布和精确定位合适的网站，以增加恢复成功。

Propagule, or seed limitation, is a little-explored factor that may have an important role in determining the distribution of native plant species in invaded grasslands. Distribution of species is classically considered to be controlled by a combination of abiotic factors, such as soil and climate, and biotic factors, such as competitors, predators, and seed bank dynamics. However, seed limitation is an additional constraint to species distributions that is poorly understood. The charismatic native wildflower sky lupine, Lupinus nanus, is an excellent model species because it has several attributes suggestive of seed limitation and it is found in a wide range of grassland habitats. Through large-scale surveys and field experiments in grasslands at the University of California McLaughlin Natural Reserve, we will determine specifically how seed availability interacts with competition and soil properties to delineate the distribution of sky lupine across multiple scales. This work has practical significance for grassland restoration because it will allow us to determine the characteristics of sites in which seed addition can result in recolonization by sky lupine, and potentially a more abundant and diverse native plant community. Given the limited resources available, restoration efforts should be focused on areas that are most likely to result in the establishment of long-term viable populations with minimal investment, areas in which native species absence is primarily a function of seed limitation. From our experiments, methodologies for native plant reinvasion will be developed that take into account interacting mechanisms limiting native plant distribution and pinpoint suitable sites to increase restoration success.