How do anthropogenic threats reorganise insect communities?

昆虫在自然和人工管理的生态系统中发挥着至关重要的作用。在世界上的一些地方，它们正在迅速减少，但这种减少的程度和原因尚未完全了解。这个项目旨在了解选定的威胁是如何重塑昆虫群落的——从结构上和总体多样性上——从而提高对哪些地方可能出现昆虫数量下降以及它们可能产生的生态影响的理解。“预测”数据库整理了数千个面临土地利用变化威胁的陆生昆虫群落的现场数据，可以对土地利用和相关压力如何影响不同的昆虫分类和功能群体进行详细建模。GLiTRS是一个由nerc资助的大型合作项目，旨在开发和验证昆虫的威胁-反应模型，它正在扩大开发一个也考虑其他威胁的数据库的方法。然而，由于这些数据库中的大多数数据源仅使用单一抽样方法对单个群体进行抽样，因此分析不能考虑群体之间的关联响应，从而限制了更机械模型的发展。这是一个问题，因为机械模型可以提供比纯粹的相关模型更丰富的生态理解，后者往往更具描述性。通过整理和综合在面临威胁的地点取样多种相互作用的昆虫（甚至非昆虫）功能群的数据集，该项目将对昆虫群落如何以及为什么发生变化提供更深入的见解。相关模型，如一般线性混合效应模型（glmm），可以测试不同的分类群或功能群对威胁的反应是否不同，甚至可以确定哪种分类方式能最大限度地提高解释力。结构方程模型等方法可以进一步测试各种可能的影响途径，包括直接和间接影响，以及在数据允许的情况下多种威胁之间的相互作用。通过访问来自GLiTRS和predict项目的数据（包括功能性状数据）以及NHM昆虫学专业知识的广度和深度，将促进这项工作。

Insects play crucial roles in natural and managed ecosystems. They have been in rapid decline in some places around the world, but the extent of and reasons for this decline are not yet fully understood. This project aims to understand how selected threats reshape insect communities - structurally as well as in terms of overall diversity - thereby improving understanding of where declines would be expected and the ecological impacts they are likely to have. The PREDICTS database, which has collated site-level data on many thousands of terrestrial insect communities facing threats relating to land-use change, allows detailed modelling of how land use and related pressures affect different taxonomic and functional groups of insects. GLiTRS, a large NERC-funded collaboration to develop and validate a threat-response model for insects, is broadening the approach in developing a database that also considers other threats. However, because most of the data sources in those databases have sampled only single groups using single sampling methods, analyses cannot consider linked responses among groups, restricting the development of more mechanistic models. This is a problem because mechanistic models can provide a much richer ecological understanding than purely correlational models, which tend to be more descriptive. By collating and then synthesising datasets that have sampled multiple interacting insect (and even non-insect) functional groups in sites facing threats, this project will deliver deeper insights into how and why insect communities are changing. Correlational models such as general linear mixed-effects models (GLMMs) can test whether different taxa or functional groups respond differently to threats, and even to determine which ways of grouping species maximise explanatory power. Approaches such as Structural Equation Modelling can go further towards testing among alternative possible impact pathways, including both direct and indirect effects plus, where data permit, interactions among multiple threats. This work will be facilitated by access to the data (including functional trait data) from the GLiTRS and PREDICTS projects and the breadth and depth of entomological expertise at NHM.