Woodland, cropland and hedgerows promote pollinator abundance in intensive grassland landscapes, with saturating benefits of flower cover
Woodland, cropland and hedgerows promote pollinator abundance in intensive grassland landscapes, with saturating benefits of flower cover
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DOI：
10.1111/1365-2664.14058
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发表时间：
2021-11-16
影响因子：
5.7
通讯作者：
Emmett, Bridget A.
中科院分区：
文献类型：
--
作者：
Alison, Jamie;Botham, Marc;Emmett, Bridget A.
传粉昆虫通过提高作物产量提供经济价值。它们在农田以外的生态系统中也具有重要的功能和文化意义。为了了解传粉媒介减少的景观级驱动因素，并指导政策和干预措施以扭转下降，研究必须涵盖(a)多种昆虫和植物分类群和(b)一系列农业和半自然土地利用。此外，在林地恢复倡议和再野化思想的时代，林地和树木线性特征（WLFs，如树篱）对传粉媒介丰度的贡献需要进一步研究。我们展示了来自全国环境调查的高质量、同地测量的精细尺度分析。我们将传粉昆虫样带计数与英国威尔士300平方公里的地面真实栖息地和WLF地图联系起来。研究了生境类型、花覆盖、WLF密度和生境多样性对鳞翅目、膜翅目和双翅目8个昆虫类群夏季（7月和8月）丰度的影响。与改良的草地（威尔士的主要生境）相比，农田和林地——尤其是阔叶林——的传粉媒介丰度始终较高。对于采蜂和两种食蚜蝇，林地生态系统的丰度预计至少比其他地方高1.5倍。此外，我们估计，在农业改善的栖息地中，WLFs对蜜蜂丰度的贡献高达14%，对食蚜蝇的贡献高达21%。所有昆虫类群的丰度都随着花的覆盖而增加，这是林地、农田和草地支持传粉昆虫的关键机制。重要的是，我们观察到增加花覆盖对非apis传粉者群体丰度的回报递减，预计每%花覆盖增加的丰度从0%到5%大约是10%到15%的两倍。然而，对于蜜蜂来说，这种关系的形状是相反的，在更高的花覆盖下，蜜蜂的丰度增加幅度更大。合成与应用。我们提供了威尔士传粉媒介丰富的驱动因素的整体视图，其中花覆盖，林地，树篱和农田是至关重要的。我们提出林地创造、树篱铺设和农田异质性在未来土地管理激励计划中的关键作用。最后，我们建议采取有针对性的干预措施，使非api传粉媒介的利益最大化。具体来说，在现有花卉覆盖较少的地区增加花卉供应——例如，在花卉贫乏的改良草原上——可以有效地增加传粉媒介的丰度和多样性，同时优先考虑野生物种而不是管理物种。
Pollinating insects provide economic value by improving crop yield. They are also functionally and culturally important across ecosystems outside of cropland. To understand landscape-level drivers of pollinator declines, and guide policy and intervention to reverse declines, studies must cover (a) multiple insect and plant taxa and (b) a range of agricultural and semi-natural land uses. Furthermore, in an era of woodland restoration initiatives and rewilding ideologies, the contribution of woodland and woody linear features (WLFs; e.g. hedgerows) to pollinator abundance demands further investigation. We demonstrate fine-scale analysis of high-quality, co-located measurements from a national environmental survey. We relate pollinator transect counts to ground-truth habitat and WLF maps across 300 1 km squares in Wales, UK. We look at effects of habitat type, flower cover, WLF density and habitat diversity on summer abundance (July and August) of eight insect groups, representing three insect orders (Lepidoptera, Hymenoptera and Diptera). Compared with improved grassland (the dominant habitat in Wales), pollinator abundance is consistently higher in cropland and woodland-especially broadleaved woodland. For mining bees and two hoverfly groups, abundance is predicted to be at least 1.5x higher in woodland ecosystems than elsewhere. Furthermore, we estimate contributions of WLFs to abundance in agriculturally improved habitats to be up to 14% for honeybees and up to 21% for hoverflies. The abundance of all insect groups increases with flower cover, which is a key mechanism through which woodland, cropland and grassland support pollinators. Importantly, we observe diminishing returns of increasing flower cover for abundance of non-Apis pollinator groups, expecting roughly twice the increase in abundance per % flower cover from 0% to 5%, as compared with 10% to 15%. However, the shape of the relationship was inverted for honeybees, which showed steeper increases in abundance at higher flower cover. Synthesis and applications. We provide a holistic view of the drivers of pollinator abundance in Wales, in which flower cover, woodland, hedgerows and cropland are critical. We propose a key role for woodland creation, hedge-laying and farmland heterogeneity within future land management incentive schemes. Finally, we suggest targeting of interventions to maximise benefits for non-Apis pollinators. Specifically, increasing floral provision in areas where existing flower cover is low-for example, in flower-poor improved grasslands-could effectively increase pollinator abundance and diversity while prioritising wild over managed species.