Arthropod decline in grasslands and forests is associated with landscape-level drivers
Arthropod decline in grasslands and forests is associated with landscape-level drivers
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DOI：
10.1038/s41586-019-1684-3
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发表时间：
2019-10-31
期刊：
影响因子：
64.8
通讯作者：
Weisser, Wolfgang W.
中科院分区：
文献类型：
--
作者：
Seibold, Sebastian;Gossner, Martin M.;Weisser, Wolfgang W.
最近关于节肢动物物种局部灭绝的报告(1)和节肢动物生物量大幅下降的报告(2)指出，土地利用集约化是生物多样性减少的主要驱动因素。然而，据我们所知，没有跨土地利用强度梯度的节肢动物出现的多点时间序列来证实因果关系。此外，目前还不清楚哪些土地利用类型和节肢动物群体受到影响，以及所观察到的生物量和多样性下降是否相互关联。在这里，我们分析了超过100万只节肢动物(约2700种)的数据，这些数据来自2008至2017年间在德国3个地区的150个草原和140个森林地点进行的标准化清查。草原和森林的总体伽马多样性随着时间的推移而下降，表明不同地点和地区的物种正在丧失。在每年采样的草地中，生物量、丰度和物种数量分别下降了67%、78%和34%。这种下降在营养水平上是一致的，主要影响稀有物种；其幅度与当地土地利用强度无关。然而，嵌入农地覆盖率较高的景观中的地点显示出更强的时间衰退。在有年度清单的30个林地中，生物量和物种数量--但不是丰度--分别下降了41%和36%。这得到了对每三年抽样的所有森林地点的分析的支持。这种下降影响了稀有和丰富的物种，而且不同营养级别的趋势有所不同。我们的结果表明，节肢动物的生物量、丰度和物种数量在营养水平上普遍下降。森林中节肢动物的减少表明，损失并不局限于开阔的栖息地。我们的结果表明，节肢动物衰退的主要驱动因素在更大的空间尺度上起作用，并且(至少对草原而言)与景观水平上的农业有关。这意味着，政策需要解决景观规模问题，以减轻土地利用做法的负面影响。
Recent reports of local extinctions of arthropod species(1), and of massive declines in arthropod biomass(2), point to land-use intensification as a major driver of decreasing biodiversity. However, to our knowledge, there are no multisite time series of arthropod occurrences across gradients of land-use intensity with which to confirm causal relationships. Moreover, it remains unclear which land-use types and arthropod groups are affected, and whether the observed declines in biomass and diversity are linked to one another. Here we analyse data from more than 1 million individual arthropods (about 2,700 species), from standardized inventories taken between 2008 and 2017 at 150 grassland and 140 forest sites in 3 regions of Germany. Overall gamma diversity in grasslands and forests decreased over time, indicating loss of species across sites and regions. In annually sampled grasslands, biomass, abundance and number of species declined by 67%, 78% and 34%, respectively. The decline was consistent across trophic levels and mainly affected rare species; its magnitude was independent of local land-use intensity. However, sites embedded in landscapes with a higher cover of agricultural land showed a stronger temporal decline. In 30 forest sites with annual inventories, biomass and species number-but not abundance-decreased by 41% and 36%, respectively. This was supported by analyses of all forest sites sampled in three-year intervals. The decline affected rare and abundant species, and trends differed across trophic levels. Our results show that there are widespread declines in arthropod biomass, abundance and the number of species across trophic levels. Arthropod declines in forests demonstrate that loss is not restricted to open habitats. Our results suggest that major drivers of arthropod decline act at larger spatial scales, and are (at least for grasslands) associated with agriculture at the landscape level. This implies that policies need to address the landscape scale to mitigate the negative effects of land-use practices.