Data from: Seasonal bee communities vary in their responses to resources at local and landscape scales: Implication for land managers

Context: There is great interest in land management practices for pollinators; however, a quantitative comparison of landscape and local effects on bee communities is necessary to determine if adding small habitat patches can increase bee abundance or species richness. The value of increasing floral abundance at a site is undoubtedly influenced by the phenology and magnitude of floral resources in the landscape, but due to the complexity of measuring landscape-scale resources, these factors have been understudied. Objectives: To address this knowledge gap, we quantified the relative importance of local versus landscape scale resources for bee communities, identified the most important metrics of local and landscape quality, and evaluated how these relationships vary with season. Methods: We studied season-specific relationships between local and landscape quality and wild-bee communities at 33 sites in the Finger Lakes region of New York, USA. We paired site surveys of wild bees, plants, and soil characteristics with a multi-dimensional assessment of landscape composition, configuration, insecticide toxic load, and a spatio-temporal evaluation of floral resources at local and landscape scales. Results: We found that the most relevant spatial scale and landscape factor varied by season. Early-season bee communities responded primarily to landscape resources, including the presence of flowering trees and wetland habitats. In contrast, mid to late-season bee communities were more influenced by local conditions, though bee diversity was negatively impacted when sites were embedded in highly agricultural landscapes. Soil composition had complex impacts on bee communities, and likely reflects effects on plant community flowering. Conclusions: Early-season bees can be supported by adding flowering trees and wetlands, while mid to late-season bees can be supported by local addition of summer and fall flowering plants. Sites embedded in landscapes with a greater proportion of natural areas will host a greater bee species diversity.Data file 'bee_abundance_richness_all_predictors_toarchive.csv': abundance and richness of wild bees at 33 sites in the Ithaca region of New York, USA with 68 variables of site and landscape quality. Landscape quality variables include topography, landscape-scale floral resources, landscape configuration and composition, and insecticide toxic load. Site quality variables include soil characteristics (texture, fertility, bulk density, water content), plant species richness, plant community composition, and site-scale floral resources. Please see README for a description of column headings in the data file ('bee_abundance_richness_all_predictors_toarchive_Mar2024.csv'). Missing values: For analyses of species richness, we excluded sites with zero abundance of wild bees (either due to compromised traps or poor-quality habitat). In the data file, these instances are indicated as richness of zero.

背景：当前学界对传粉者（pollinators）友好的土地管理实践关注度颇高，但要明确添加小型生境斑块（habitat patches）能否提升蜂类多度（bee abundance）或物种丰富度（species richness），亟需开展景观与局地因子对蜂类群落（bee communities）影响的定量对比研究。提升样地花丰度（floral abundance）的价值，无疑会受到景观中花资源物候（phenology）与总量的影响，但由于景观尺度（landscape-scale）资源的量化难度较高，此类因素尚未得到充分研究。

研究目标：为填补这一认知空白，本研究定量解析了局地与景观尺度花资源对蜂类群落的相对重要性，明确了局地与景观质量的关键指标，并评估了这些关联随季节的变化规律。

研究方法：以美国纽约州五指湖地区的33个样点为研究对象，分析了局地与景观质量和野生蜂类群落间的季节特异性关联。研究将野生蜂类、植物与土壤特征的样地调查数据，与景观组成、配置、杀虫剂毒性负荷的多维度评估结果，以及局地和景观尺度花资源的时空量化分析相结合。

研究结果：本研究发现，最具相关性的空间尺度与景观因子随季节发生显著变化。早春蜂类群落主要响应景观尺度资源，包括开花乔木与湿地生境的分布。与之相反，中晚季蜂类群落更多受局地条件影响，但当样地嵌入高度农业化的景观中时，蜂类多样性会受到负面影响。土壤组成对蜂类群落存在复杂影响，这大概率反映了其对植物群落开花过程的调控作用。

研究结论：通过种植开花乔木与恢复湿地可支撑早春蜂类种群；而通过局地添加夏秋开花植物，则可助力中晚季蜂类种群。样地所在景观的自然生境占比越高，其承载的蜂类物种多样性也就越丰富。

数据集文件`bee_abundance_richness_all_predictors_toarchive.csv`：包含美国纽约州伊萨卡地区33个样点的野生蜂类多度与物种丰富度数据，附带68项样地与景观质量变量。其中景观质量变量涵盖地形、景观尺度花资源、景观配置与组成、杀虫剂毒性负荷；样地质量变量包括土壤特征（质地、肥力、容重、含水量）、植物物种丰富度、植物群落组成以及样地尺度花资源。有关该数据集`bee_abundance_richness_all_predictors_toarchive_Mar2024.csv`的列标题说明，请参阅README文件。

缺失值说明：在物种丰富度分析中，我们排除了野生蜂类多度为0的样点（此类样点可能因诱捕器故障或生境质量不佳导致），在数据文件中此类情况以物种丰富度为0进行标记。