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

栖息地碎片化、全球传粉者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？在人类干扰的生境中，植物与传粉者之间的相互作用被破坏，导致植物自交受精的比率增加(种子由同一朵花的花粉产生，而不是来自另一种植物)。由于自花受精产生的后代更有可能存活和繁殖减少，一个主要的保护问题涉及到对单个植物的传粉者服务的损失是否以及如何扩大到影响植物种群的增长和持久性。这项研究将从实验上评估不同生态条件下自受精频率的变化对种群增长的影响。重点物种受到栖息地碎片化的影响，在几个州被列为濒危物种。这些发现将有助于我们更广泛地理解和预测这些物种和其他类似动植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。公民科学家将收集野生种群的年度调查数据。一名博士后助理、研究生和许多本科生将接受研究和推广技能方面的培训。这个项目使用了一个强大的实验人口统计学方法来评估交配系统(近亲交配模式)对自交亲和植物Sabatia angularis(Rossepin)在竞争环境中种群增长的影响。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)将通过人工授粉和对比割草制度直接操纵。所有人的人口统计命运将在三代人的时间内得到跟踪。人口统计数据将被用来对模型进行参数化，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来调查实验处理中观察到的增长率变化(或相似)的根本原因。人口统计学模型也将被构建来模拟实验中的交配系统梯度，将先前静态近亲繁殖抑制的估计纳入计算机中，并将结果与实验结果进行比较。研究结果将进一步解决遗传负荷、选择的人口成本以及种内变异对物种共存的影响的生态影响。

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.