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

栖息地破碎化、全球传粉媒介的减少和土地利用的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中，植物与其传粉者之间的相互作用正在被破坏，导致植物自花受精率增加（种子由来自同一朵花的花粉产生，而不是来自另一株植物）。由于自花受精产生的后代更有可能减少生存和繁殖，一个主要的保护问题涉及到是否以及如何损失授粉服务的个别植物规模扩大，影响植物种群的增长和持久性。本研究将通过实验评估不同生态条件下自花受精频率的变化对种群增长的影响。重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。这些发现将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夏令营中领导植物授粉者相互作用的教育计划。民间科学家将收集野生种群的年度调查数据。博士后助理，研究生和许多本科生将接受研究和推广技能的培训。本项目采用了一个强大的实验人口统计学方法来评估交配系统（模式的近亲繁殖）的影响，一个自我兼容的植物，Sabatia angularis（rosepin），在竞争环境中的人口增长。通过人工授粉和对比刈割制度，直接控制实验种群的自交率（0%，25%，50%，75%，100%）和竞争环境（高与低种间竞争）。所有人的人口命运将在三代人的时间内得到跟踪。人口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、存活、繁殖力）和种群增长率的影响，包括非线性关系。将通过额外的人口统计学分析研究在实验治疗中观察到的生长速率变化（或相似性）的根本原因。还将构建人口统计学模型，通过将先前的静态近交衰退估计纳入计算机模拟和与实验结果相比的结果，来模拟实验交配系统梯度。研究结果将进一步解决遗传负荷的生态影响，选择的人口成本，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.