Collaborative Research: Demographic heterogeneity in landscapes and communities

一个种群中的个体并不完全相同。相反，由于他们的基因构成和成长环境的不同，包括父母对待他们的方式，他们在身体上和行为上都不同。这导致群体中的个体有不同的出生和死亡机会，这一现象被称为人口异质性。虽然这种现象普遍存在，但在对动物或植物种群的研究中很少考虑到这种现象。负责该项目的研究人员之前的理论工作表明，人口异质性可以增加种群的增长速度和环境所能支持的最大个体数量，降低种群灭绝的风险。该项目的新工作将扩展这一理论，将物种之间的相互作用包括在内，并用它来预测受到保护关注的野生种群--佛罗里达灌木松鸦的未来。首先，理论模型将被扩展，以解释这样一个事实，即生物种群并不是孤立的，而是通过竞争和通过进食和被吃掉与其他物种相互作用。研究将有助于理解异质性是使物种更容易共存还是更难共存，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，空间模型将被用来研究当个体主要与其近邻互动时，人口异质性如何影响种群动态，例如在植物中。为了开始将模型应用于真实的种群，该项目将使用从佛罗里达州中部的灌木鸟种群收集的数据，其他研究人员自1969年以来一直在研究这些数据。佛罗里达灌木鸦有一种不同寻常的社会结构，这种结构促进了种群的异质性：年轻人经常帮助他们的父母抚养更年轻的兄弟姐妹，既提高了父母的繁殖成功，也提高了他们自己随后的繁殖。利用最近的统计进展，该项目将衡量人口中的人口异质性的数量，并预测这种异质性对人口未来增长和生存的影响。该项目将培训一名博士后研究人员和一名研究生，提高对个人和群体之间联系的科学理解，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.