Effects of mating system change on population dynamics: an experimental test across competitive contexts

生境破碎化、全球传粉媒介减少和土地利用变化正在迅速改变植物种群的生态条件。在这个日益变化的世界里，植物种群的命运是什么？在人类干扰的栖息地，植物与其传粉者之间的相互作用被破坏，导致植物自花受精率增加（来自同一花的花粉与来自另一种植物的花粉产生的种子）。由于自花受精产生的后代更有可能降低生存和繁殖能力，因此一个主要的保护问题涉及到单个植物传粉者服务的丧失是否以及如何扩大影响植物种群的生长和持久性。本研究将实验评价不同生态条件下自交受精频率的变化对种群生长的影响。焦点物种受到栖息地破碎化的影响，在几个州被列为濒危物种。研究结果将广泛地有助于我们理解和预测这些和其他类似的植物和动物物种在不断变化的世界中的命运。此外，研究人员将实施推广计划，在每年的K-6夏令营中领导植物与传粉者相互作用的教育计划。每年野生种群的调查数据将由公民科学家收集。一名博士后、研究生和众多本科生将接受研究和拓展技能方面的培训。本项目采用一种强大的实验人口统计学方法来评估交配系统（近亲繁殖模式）对竞争环境下自交植物沙巴atia angularis （rosepin）种群增长的影响。实验群体的自交率（0%、25%、50%、75%、100%）和竞争环境（高与低种间竞争）将通过人工授粉和对比刈割制度直接控制。所有人的人口命运都将延续三代。人口统计数据将用于参数化模型，从中可以得出人口动态。将评估自交率、竞争环境及其相互作用对生命率（生长、生存、繁殖力）和人口增长率的影响，包括非线性关系。在实验处理中观察到的增长率变化（或相似之处）的潜在原因将通过额外的人口统计学分析进行调查。人口统计学模型也将被构建来模拟实验交配系统的梯度，通过结合先前的静态近交下降估计和与实验结果相比较的结果。研究结果将进一步探讨遗传负荷的生态影响、种群选择成本以及种内变异对物种共存的影响。

Habitat fragmentation, global pollinator declines, and land use change are rapidly transforming ecological conditions in plant populations. What is the fate of plant populations in this increasingly altered world? Interactions between plants and their pollinators are being disrupted in human-disturbed habitats, leading to increased rates of self-fertilization (seeds produced with pollen from the same flower vs. from another plant) by plants. Because offspring produced by self-fertilization are more likely to have decreased survival and reproduction, a major conservation concern relates to whether and how loss of pollinator services for individual plants scales up to influence plant population growth and persistence. This research will experimentally evaluate the impact of changes in the frequency of self-fertilization on population growth under different ecological conditions. The focal species is affected by habitat fragmentation and is classified as imperiled in several states. Findings will contribute broadly to our understanding of and ability to predict the fates of these and other similar plant and animal species in a changing world. Additionally, the researcher will implement outreach programs, leading educational programs in plant-pollinator interactions at yearly K-6 summer camps. Yearly survey data of wild populations will be collected by citizen scientists. A postdoctoral associate, graduate student, and numerous undergraduates will be trained in research and outreach skills. This project employs a powerful experimental demographic approach to evaluate the impact of mating system (pattern of inbreeding) on population growth of a self-compatible plant, Sabatia angularis (rosepin), across competitive contexts. Selfing rate (0%, 25%, 50%, 75%, 100%) and competitive context (high vs. low interspecific competition) of experimental populations will be directly manipulated through hand pollinations and contrasting mowing regimes. The demographic fates of all individuals will be followed over three generations. Demographic data will be used to parameterize models from which population dynamics can be derived. The impact of selfing rate, competitive context, and their interaction on vital rates (growth, survival, fecundity) and population growth rate will be evaluated, including non-linear relationships. The underlying causes of observed changes (or similarities) in growth rate across experimental treatments will be investigated with additional demographic analyses. Demographic models will also be constructed to mimic the experimental mating-system gradient by incorporating prior static inbreeding depression estimates in silico and outcomes compared to experimental results. Research findings will further address the ecological impacts of genetic load, demographic costs of selection, and impacts of intraspecific variation on species coexistence.