Global Change Research Group, Mediterranean Institute for Advanced Studies (UIB-CSIC), Esporles, Spain.
Department of Biology, Laboratory of Botany, Research Group on Plant Biology under Mediterranean Conditions, University of the Balearic Islands, Palma, Spain.
Ecol Appl. 2022 Sep;32(6):e2634. doi: 10.1002/eap.2634. Epub 2022 Jun 26.
Loss of habitats and native species, introduction of invasive species, and changing climate regimes lead to the homogenization of landscapes and communities, affecting the availability of habitats and resources for economically important guilds, such as pollinators. Understanding how pollinators and their interactions vary along resource diversity gradients at different scales may help to determine their adaptability to the current diversity loss related to global change. We used data on 20 plant-pollinator communities along gradients of flower richness (local diversity) and landscape heterogeneity (landscape diversity) to understand how the diversity of resources at local and landscape scales affected (1) wild pollinator abundance and richness (accounting also for honey bee abundance), (2) the structure of plant-pollinator networks, (3) the proportion of actively selected interactions (those not occurring by neutral processes), and (4) pollinator diet breadth and species' specialization in networks. Wild pollinator abundance was higher overall in flower-rich and heterogeneous habitats, while wild pollinator richness increased with flower richness (more strongly for beetles and wild bees) and decreased with honeybee abundance. Network specialization (H '), modularity, and functional complementarity were all positively related to floral richness and landscape heterogeneity, indicating niche segregation as the diversity of resources increases at both scales. Flower richness also increased the proportion of actively selected interactions (especially for wild bees and flies), whereas landscape heterogeneity had a weak negative effect on this variable. Overall, network-level metrics responded to larger landscape scales than pollinator-level metrics did. Higher floral richness resulted in a wider taxonomic and functional diet for all the study guilds, while functional diet increased mainly for beetles. Despite this, specialization in networks (d') increased with flower richness for all the study guilds, because pollinator species fed on a narrower subset of plants as communities became richer in species. Our study indicates that pollinators are able to adapt their diet to resource changes at local and landscape scales. However, resource homogenization might lead to poor and generalist pollinator communities, where functionally specialized interactions are lost. This study highlights the importance of including different scales to understand the effects of global change on pollination service through changes in resource diversity.
生境丧失和本地物种的减少、入侵物种的引入以及气候变化导致景观和群落同质化，影响了对经济上重要类群（如传粉者）可用生境和资源的供给。了解传粉者及其相互作用如何沿着不同尺度的资源多样性梯度变化，可能有助于确定它们对与全球变化相关的当前多样性丧失的适应能力。我们使用了 20 个植物-传粉者群落的数据，这些群落沿着花的丰富度（本地多样性）和景观异质性（景观多样性）梯度变化，以了解本地和景观尺度上资源多样性如何影响（1）野生传粉者的丰度和丰富度（也考虑了蜜蜂的丰度），（2）植物-传粉者网络的结构，（3）主动选择的相互作用的比例（那些不是由中性过程发生的相互作用），以及（4）传粉者的饮食广度和网络中物种的专业化。在花丰富和异质的栖息地中，野生传粉者的丰度总体上较高，而野生传粉者的丰富度则随着花的丰富度增加（对甲虫和野生蜜蜂的影响更强），随着蜜蜂的丰度增加而减少。网络专业化（H '）、模块性和功能互补性都与花的丰富度和景观异质性呈正相关，表明随着资源多样性在两个尺度上的增加，生态位分离。花的丰富度也增加了主动选择的相互作用的比例（特别是对野生蜜蜂和苍蝇），而景观异质性对此变量的影响较弱。总体而言，网络水平的指标对较大的景观尺度的反应比传粉者水平的指标更敏感。较高的花的丰富度导致所有研究类群的分类学和功能饮食范围更广，而功能饮食主要增加了甲虫的饮食范围。尽管如此，由于群落中物种变得更加丰富，传粉者物种只食用植物的一个较窄子集，因此所有研究类群的网络专业化（d'）都随着花的丰富度增加而增加。我们的研究表明，传粉者能够适应本地和景观尺度上的资源变化。然而，资源同质化可能导致传粉者群落质量较差且以广谱为主，功能上专门的相互作用丧失。本研究强调了在不同尺度上包括不同尺度以了解全球变化通过资源多样性的变化对传粉服务的影响的重要性。
