Effects of an agri-environment scheme on bumblebee reproduction at local and landscape scales
Effects of an agri-environment scheme on bumblebee reproduction at local and landscape scales
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DOI：
10.1016/j.baae.2015.05.006
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发表时间：
2015-09-01
影响因子：
3.8
通讯作者：
Heard, Matthew S.
中科院分区：
文献类型：
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作者：
Carvell, Claire;Bourke, Andrew F. G.;Heard, Matthew S.
农业环境计划（AES）已在欧洲各地实施，旨在减轻农业生态系统中栖息地丧失对一系列数量下降物种的影响。这些物种包括授粉昆虫，如大黄蜂，已有研究表明AES对其数量和物种丰富度有积极影响。然而，无论是在局部还是景观尺度上，都缺乏AES对目标物种繁殖影响的证据。我们在呈现农业强度梯度的不同景观中进行了一项大规模研究，以调查种植在三种不同大小斑块中的一种有针对性的花卉混合物对每个景观内重复样带上大黄蜂有性个体（雄蜂和蜂王）总生物量指数的影响。我们将该指数（MQ）用作大黄蜂繁殖的衡量指标。在控制了样带上的花卉密度之后，我们发现在为期三年的研究中，在局部尺度上，播种花卉斑块上的MQ显著高于常规管理的对照斑块。虽然播种花卉斑块并没有显著增加周围景观中的MQ，但在较大（1公顷）播种斑块周围的景观中MQ高于较小（0.25公顷）播种斑块周围的景观。我们的研究结果表明，虽然不同蜂种的反应可能因所种植的植物种类而异，但有针对性的花卉混合物可以通过为觅食距离内蜂巢中的所有等级和性别的大黄蜂提供具有本地吸引力的觅食资源来促进大黄蜂的繁殖。如果建立的规模足够大，播种花卉斑块可能会导致繁殖个体可检测到地扩散到周围景观中。此外，播种斑块对MQ的影响受到景观环境的调节，在耕地比例高的地点检测到最强的积极反应。这支持了先前的研究结果，即AES可以在农业集约化程度更高的景观中为传粉者带来更大的净效益。
Agri-environment schemes (AES) have been implemented across Europe, aiming to mitigate effects of habitat loss in agroecosystems for a range of declining species. These include pollinating insects such as bumblebees, for which positive effects of AES on abundance and species richness have been shown. However, there is a lack of evidence for effects of AES on reproduction of target species, at either local or landscape scales, We conducted a large-scale study across landscapes exhibiting a gradient of agricultural intensity to investigate the effects of a targeted flower mixture, sown in patches of three different sizes, on an index of the total biomass of bumblebee sexuals (males and queens) on replicated transects within each landscape. We used this index (MQ) as a measure of bumblebee reproduction. After controlling for floral density on transects, we found that MQ was significantly higher on sown flower patches than on conventionally managed control patches at local scales throughout the three-year study. While sown flower patches did not significantly increase MQ in surrounding landscapes, MQ was higher in landscapes surrounding larger (I ha) than smaller (0.25 ha) sown patches. Our results suggest that, while responses of different bee species may vary depending on the plant species sown, targeted flower mixtures can enhance bumblebee reproduction by providing locally attractive forage resources to bumblebees of all castes and sexes from nests within foraging distance. If established at large enough scales, sown flower patches may lead to a detectable spill-over of reproductives into surrounding landscapes. Furthermore, effects of sown patches on MQ were moderated by landscape context, the strongest positive responses being detected at sites with high proportions of arable land. This supports previous findings that AES can deliver greater net benefits for pollinators in more intensively farmed landscapes.