Department of Entomology, University of California, Riverside, CA, 92521, USA.
Oecologia. 2022 Mar;198(3):773-783. doi: 10.1007/s00442-022-05135-6. Epub 2022 Feb 24.
In human-modified landscapes, understanding how habitat characteristics influence the diversity and composition of beneficial organisms is critical to conservation efforts and modeling ecosystem services. Assessing turnover, or the magnitude of change in species composition across sites or through time, is crucial to said efforts, yet is often overlooked. For pollinators such as wild bees, variables influencing temporal turnover, particularly across seasons within a year, remain poorly understood. To investigate how local and landscape characteristics correlate with bee diversity and turnover across seasons, we recorded wild bee and flowering ornamental plant assemblages at 13 plant nurseries in California between spring and autumn over 2 years. Nurseries cultivate a broad diversity of flowering plant species that differ widely across sites and seasons, providing an opportunity to test for correlations between turnover and diversity of plants and bees. As expected, we documented strong seasonal trends in wild bee diversity and composition. We found that local habitat factors, such as increased cultivation of native plants, were positively associated with bee diversity in sweep netting collections, whereas we detected moderate influences of landscape level factors such as proportion of surrounding natural area in passive trap collections. We also detected a moderate positive correlation between the magnitude of turnover in plant species and that of bee species (as number of taxa gained) across consecutive seasons. Our results have implications for the conservation of wild bees in ornamental plant landscapes, and highlight the utility of plant nurseries for investigating hypotheses related to diversity and turnover in plant-pollinator systems.
在人类改造的景观中，了解栖息地特征如何影响有益生物的多样性和组成对于保护工作和生态系统服务建模至关重要。评估物种组成在地点或时间上的变化程度（即周转率）对于这些努力至关重要，但往往被忽视。对于传粉媒介如野生蜜蜂，影响时间周转率的变量，特别是在一年中的不同季节之间，仍然知之甚少。为了研究本地和景观特征如何与蜜蜂多样性和季节间周转率相关，我们在加利福尼亚的 13 家苗圃中，在两年内的春季和秋季之间，记录了野生蜜蜂和开花观赏植物的组合。苗圃种植了广泛的开花植物物种，这些物种在不同地点和季节差异很大，为检验植物和蜜蜂周转率与多样性之间的相关性提供了机会。正如预期的那样，我们记录了野生蜜蜂多样性和组成的强烈季节性趋势。我们发现，本地生境因素，如增加本土植物的种植，与网捕收集的蜜蜂多样性呈正相关，而我们在被动诱捕收集的景观水平因素（如周围自然区域的比例）中检测到适度的影响。我们还在连续季节的植物物种周转率和蜜蜂物种周转率（以获得的分类群数量为指标）之间检测到适度的正相关。我们的研究结果对观赏植物景观中野生蜜蜂的保护具有重要意义，并强调了植物苗圃在研究与植物-传粉媒介系统多样性和周转率相关的假设方面的效用。
