Functional traits of carabid beetles reveal seasonal variation in community assembly in annual crops - SCRIPT & DATASET

The uploaded documents correspond to the raw data and script of statistical analyses used in the research study "Functional traits of carabid beetles reveal seasonal variation in community assembly in annual crops" currently published as a preprint on bioRxiv (https://doi.org/10.1101/2021.02.04.429696) and under review in PCI Ecology. Here is the abstract of the preprint: <strong>1.</strong> Trait-based community assembly studies have mostly been addressed along spatial gradients, and do not consider explicitly a fundamental dimension governing community assembly, the time. Nevertheless, such consideration seems particularly necessary in systems in which organisms have to face regular disturbances and rapid changes in vegetation phenology, such as in intensively managed farmlands. <strong>2.</strong> In this study, we aimed at understanding how the functional diversity of carabid beetle communities varied across the growing season in response to crop type. We tested three alternative hypotheses on mechanisms underlying the community assembly. <strong>3.</strong> We used data from a long-term monitoring conducted over nine years in an intensively-managed farmland in central western France, in a total of 625 fields. First, we measured morphological traits related to body size, dispersal mode, and resource acquisition on the 13 dominant carabid species (&gt; 85 % of all trapped individuals) and identified three independent dimensions of functional specialization within our species pool along axes of a PCA and highlighted key traits for community assembly. Second, we evaluated the community assembly temporal dynamics and the impact of habitat filtering and niche differentiation in the different crop types with time, using linear mixed-effects models. <strong>4.</strong> We showed that functional species assembly of carabid beetle communities occurring in crop fields varies importantly intra-annually, with strong variations in these dynamics depending on crop type and crop phenology. Each crop acted as a filter on carabid communities for body size and resource-acquisition traits, and functional differentiation between crops increased with time. We did not find any evidence of habitat filtering on traits related to dispersal mode. <strong>5. </strong>Our results emphasize the major role of crop phenology but also disturbances involved by agricultural practices such as crop harvesting on changes in community assembly, likely due to seasonal and inter-annual redistributions of species in agricultural landscapes in response to such changes. The temporal dimension cannot be ignored to understand the assembly of local carabid communities in farmlands.本上传文档对应于研究论文《步甲科甲虫（carabid beetles）功能性状揭示一年生作物群落组装的季节变异》的原始数据与统计分析脚本，该论文目前已在bioRxiv平台发布预印本（DOI: 10.1101/2021.02.04.429696），并正在《PCI Ecology》期刊审稿中。以下为该预印本的摘要： 1. 以性状为基础的群落组装研究大多沿空间梯度开展，并未明确考量调控群落组装的核心维度——时间维度。然而，在生物需频繁应对干扰、植被物候快速变化的生态系统（如集约化农田）中，纳入时间维度的考量显得尤为必要。 2. 本研究旨在明晰步甲科甲虫群落的功能多样性在整个生长季内如何随作物类型发生变化，并针对群落组装的潜在机制提出了3种备择假设。 3. 本研究使用了法国中西部一处集约化农田中为期9年的长期监测数据，共覆盖625块样田。首先，我们对13个优势步甲物种（捕获个体占总捕获量的85%以上）的体型大小、扩散模式与资源获取相关形态性状进行了测定；基于主成分分析（PCA）的轴维度，我们在物种库中识别出功能特化的3个独立维度，并明确了群落组装的关键性状。其次，我们采用线性混合效应模型，评估了不同作物类型下群落组装的时间动态，以及生境过滤与生态位分化随时间的影响。 4. 研究结果表明，农田中步甲科甲虫群落的物种功能组装在年内存在显著变化，且其动态随作物类型与作物物候呈现出强烈差异。各类作物均会对步甲群落的体型与资源获取性状产生过滤作用，且作物间的功能分化随时间推移逐渐加剧。未发现扩散模式相关性状受到生境过滤的证据。 5. 本研究结果凸显了作物物候以及作物收割等农业实践所带来的干扰，在群落组装变化中的核心作用，这一现象可能源于农业景观中物种为响应此类变化而发生的季节间与年际间重新分布。若要理解农田中本地步甲群落的组装机制，时间维度的考量不可或缺。