Collaborative Research: Demographic heterogeneity in landscapes and communities

种群中的个体是不相同的。相反，由于基因组成和成长环境的差异，包括父母对待他们的方式，他们在身体上和行为上都存在差异。这导致种群中的个体有不同的出生和死亡机会，这种现象被称为人口异质性。尽管这一现象很普遍，但在动物或植物种群的研究中很少考虑到这一现象。主持该项目的研究人员先前的理论工作表明，人口异质性可以提高人口的增长率和环境所能支持的最大个体数量，从而降低人口灭绝的风险。该项目的新工作将扩展这一理论，包括物种之间的相互作用，并用它来预测一种受保护的野生种群——佛罗里达灌丛鸦的未来。首先，理论模型将被扩展，以解释生物种群不是孤立的，而是通过竞争、吃和被吃与其他物种相互作用的事实。研究将有助于了解异质性是使物种共存更容易还是更困难，以及竞争或捕食能力的个体差异如何影响不同物种群落的动态和长期持久性。其次，空间模型将用于研究当个体主要与其近邻（如植物）相互作用时，人口异质性如何影响种群动态。为了将模型应用于实际种群，该项目将使用从佛罗里达州中部收集的灌丛鸦种群数据，其他研究人员自1969年以来一直在研究这些数据。佛罗里达灌丛鸦有一种不同寻常的社会结构，促进了人口的异质性：年轻的成年鸟经常帮助它们的父母抚养年幼的兄弟姐妹，这既提高了父母的繁殖成功率，也提高了自己随后的繁殖成功率。利用最近的统计进展，该项目将测量人口中人口异质性的数量，并预测这种异质性对人口未来增长和生存的影响。该项目将培养一名博士后研究员和一名研究生，提高对个体与种群之间联系的科学认识，并帮助开发保护生物多样性的工具。

Individuals within a population are not identical. Instead, they differ from one another physically and in their behavior, due to differences in their genetic make-up and in the environments in which they grow up, including how they are treated by their parents. This causes individuals in a population to have different chances of birth and death, a phenomenon known as demographic heterogeneity. Although widespread, this phenomenon has rarely been considered in studies of populations of animals or plants. Previous theoretical work by the researchers heading this project has suggested that demographic heterogeneity can increase the rate of growth of a population and the maximum number of individuals that the environment can support, reducing the risk that the population will go extinct. The new work for the project will expand this theory to include interactions between species and use it to predict the future of a wild population of conservation concern, the Florida scrub jay. First, the theoretical model will be extended to account for the fact that biological populations are not isolated, but interact with other species through competition and through eating and being eaten. Research will help understand whether heterogeneity makes it easier or harder for species to coexist, and how individual variation in competitive or predatory ability affects the dynamics and long-term persistence of a community of different species. Second, spatial models will be used to examine how demographic heterogeneity affects population dynamics when individuals mainly interact with their immediate neighbors, as in plants. To start to apply the models to real populations, the project will use data collected on a population of scrub jays in central Florida, which other researchers have studied since 1969. Florida scrub jays have an unusual social structure that promotes demographic heterogeneity: young adults often help their parents raise younger siblings, improving both the breeding success of their parents and their own subsequent breeding. Using recent statistical advances, the project will measure the amount of demographic heterogeneity in the population and project the impact of that heterogeneity on the population's future growth and survival. The project will train a post-doctoral researcher and a graduate student, improve scientific understanding of the link between individuals and populations, and help develop tools for the conservation of biodiversity.