Allometric models of spatial meta-community food webs

该项目将解决复杂的空间和营养网络的相互作用。营养网络由物种组成，这些物种通过它们在当地栖息地的摄食相互作用联系在一起。空间网络由局部栖息地组成，作为非连续景观的斑块。这些斑块是由物种的斑块间分散联系在一起的。一个物种的丰度和生存取决于局部斑块内的摄食相互作用以及斑块之间的分散。一方面，斑块空间网络的结构影响当地种群密度，最终影响物种相互作用的营养网络。另一方面，营养网络的结构影响当地种群密度和生存，并对分散率和相连生境斑块的空间网络产生连锁效应。拟议的项目将有三个主要的工作包，解决(1)自然生态系统的经验模式，(2)空间网络对营养网络的影响，(3)反之亦然。实证分析将解决(1)体重与扩散距离之间的关系（即大型物种可以跨越更大距离的定量描述），(2)栖息地斑块自然网络的结构（卫星图像分析栖息地斑块如何在景观中分布），以及(3)复杂营养网络在空间上的周转。我们将在我们提出的项目的理论部分使用这些经验模式，并继续使它们可用于本研究单元的其他项目。我们项目的模型分析将基于描述斑块内（例如，生物量生产，营养相互作用）和斑块间过程（扩散）的常微分方程（ODE）系统。这些ode的整合将产生物种生物量密度的时间序列，将对持久性（生存）、种群稳定性（例如，生物量密度变异系数）以及当地（在斑块上）和全球（在所有斑块上整合）的营养网络结构进行分析。本文主要研究两个问题：(1)空间网络结构和斑块异质性在联系和非生物变量方面如何影响营养网络的持久性、稳定性和结构；(2)物种之间以及物种与非生物环境之间的营养相互作用如何塑造营养网络中涌现的空间网络及其空间变异性？

This project will address the interplay of complex spatial and trophic networks. Trophic networks are composed of species that are linked by their feeding interactions in local habitats. Spatial networks comprise local habitat as patches of a non-continuous landscape. These patches are linked by the inter-patch dispersal of the species. The abundance and survival of a species depend on the feeding interactions within the local patches as well as on the dispersal between patches. On the one hand, the structure of the spatial network of patches has effects on the local population densities and eventually the trophic network of species interactions. On the other hand, the structure of the trophic network affects local population densities and survival with knock-on effects on dispersal rates and the spatial network of connected habitat patches. The proposed project will have three major work packages addressing (1) empirical patterns in natural ecosystems, (2) spatial network effects on trophic networks and (3) vice versa. The empirical analyses will address (1) the relationships between body masses and dispersal distances (i.e., quantitative descriptions that large species can bridge larger distances), (2) the structure of natural networks of habitat patches (satellite image analyses how habitat patches are distributed across landscapes), and (3) the turnover of complex trophic networks across space. We will employ these empirical patterns in the theoretical parts of our proposed project and also continue to make them available for the other projects of this research unit. The model analyses of our project will be based on systems of ordinary differential equations (ODE) describing intra-patch (e.g., biomass production, trophic interactions) and inter-patch processes (dispersal). Integration of these ODEs will yield time series of species biomass densities that will be analysed for persistence (survival), population stability (e.g., coefficient of variation in biomass densities), and the local (on patches) and global (integrated across all patches) trophic network structures. We will address two main questions: (1) how does the structure of the spatial network and patch heterogeneity in terms of linkedness as well as abiotic variables affect the persistence stability and structure of the trophic networks; (2) how do trophic interactions among species and between species and the abiotic environment shape the emergent spatial network and the resulting spatial variability in the trophic network?