Trait-mediated density-dependence and community level eco-evolutionary dynamics

科学家们通过观察、实验和数学建模的结合，对一个系统有了很好的了解。如果生物学家能够建立一个模型，用来准确地预测野外种群和群落的行为，他们就对这个系统有了很好的了解。不幸的是，对于大多数自由生活的人群和社区来说，构建这样的模型是一个真正的挑战。这有几个原因。首先，收集足够多的观测数据来对模型进行鲁棒参数化是费时且昂贵的。其次，大多数自然系统不容易进行实验操作，而实验操作对于获得无法仅通过观察获得的见解是无价的。第三，当系统受到干扰时，种群和社区的多个方面通常会同时发生变化，包括种群规模的动态、幼崽和成年崽的平均体型、基因频率和出生时预期寿命等生活史特征。直到最近，生物学家才成功地同时对种群、基因和性状的动态进行建模。这些模型被称为积分投影模型。虽然整体投影模型为理解自然系统的动态提供了巨大的潜力，但它们的发展仍处于起步阶段。特别是对待同一物种的个体之间的竞争的态度是天真的。此外，使用这些模型来探索群落内物种相互作用的方式还有大量的工作要做。在这个提议中，我们将从已经发表的包括同一物种个体之间竞争的整体预测模型开始，并将使用新的方法来分析它们，以获得关于个体之间不同类型的竞争如何同时影响种群规模、体型和生活史的动态的一般见解。接下来，我们将使用特立尼达淡水鱼群落的一些非常详细的实验数据来建立物种相互作用的模型。我们将使用这些模型来预测自然溪流的动态，这些动态已经被观察了很多年。因此，拟议的工作非常物有所值，因为我们将使用如此广泛的现有数据。通过对我们的模型进行一系列分析，并可能进行一些额外的实验，我们希望建立能够准确捕捉自然溪流群落动态的模型。到工作结束时，我们期望对这个系统的动力学比研究中任何其他自由生活的社区都有更好的了解。

Scientists achieve good understanding about a system through a mixture of observation, experimentation and mathematical modeling. If biologists can build a model that can be used to accurately predict the behavior of populations and communities in the wild, they have a good understanding of the system. Unfortunately constructing such models is a real challenge for most free-living populations and communities. There are several reasons for this. First, it is time consuming and expensive to collect a sufficiently large quantity of observational data to robustly parameterize models. Second, most natural systems do not easily lend themselves to experimental manipulation that are invaluable in gaining insight that cannot be reached from observation alone. Third, multiple aspects of populations and communities often change together when the system is perturbed, including the dynamics of population size, average body size of juveniles and adults, gene frequencies and life history traits like life expectancy at birth. It is only recently that biologists have worked out to simultaneously model the dynamics of populations, genes and traits. These models are called integral projection models.Although integral projection models offer enormous potential for understanding the dynamics of natural systems, their development is still in its infancy. In particular the treatment of competition between individuals of the same species is treated naively. In addition, there is considerable work to be done to use these models to explore the way species within a community interact. In this proposal we will start by taking already published integral projection models that include competition between individuals of the same species and will use novel methods to analyze them to gain general insight into how different types of competition between individuals simultaneously impacts the dynamics of population size, body size and life history. Next, we will use some exceptional detailed experimental data from a freshwater fish community in Trinidad to build models of interacting species. We will use these models to predict the dynamics of natural streams where dynamics have been observed for many years. The proposed work is consequently exceptionally good value for money because we will use such extensive existing data. Through a series of analyses of our models, and potentially some additional experiments, we expect to build models that accurately capture the dynamics of the natural stream community. By the end of the work we expect to have achieved a better understanding of the dynamics of this system than of any other free-living community under study.