Inconsistent responses of carabid beetles and spiders to land-use intensity and landscape complexity in Northwestern Europe

Reconciling biodiversity conservation with agricultural production requires a better understanding of how key ecosystem service providing species respond to agricultural intensification. Carabid beetles and spiders represent two widespread guilds providing biocontrol services. Here we surveyed carabid beetles and spiders in 66 winter wheat fields in four Northwestern European countries and analyzed how the activity density and diversity of carabid beetles and spiders were related to crop yield (proxy for land-use intensity), percentage cropland (proxy for landscape complexity) and soil organic carbon content, and whether these patterns differed between dominant and non-dominant species. Less than 17% of carabid or spider species were classified as dominant, which accounted for more than 90% of individuals respectively. We found that carabids and spiders were generally related to different aspects of agricultural intensification. Carabid species richness was positively related with crop ..., We used data on natural enemy communities in 66 paired winter wheat fields in four Northwestern European countries (Germany, the Netherlands, Sweden and United Kingdom) to investigate the response of natural enemy communities to landscape complexity, local land-use intensity and soil organic matter content, and specifically examined whether and how responses differ between dominant and non-dominant species. We focused on carabid beetles and spiders as they represent the two groups of natural enemies in arable fields in Northwestern European and widely used as bioindicators (Lang et al., 1999; Borchard et al., 2014). We used pitfall traps to collect carabids and spiders in field pairs that covered a gradient in land-use intensity and landscape complexity, with fields within pairs having contrasting soil organic carbon content. 
Pitfall traps (polypropylene beakers 155 mm high and 95 mm across) were used to survey ground-dwelling arthropods during the wheat flowering season (late May to e...,

协调生物多样性保护与农业生产，需更深入解析关键生态系统服务提供物种对农业集约化的响应规律。步甲科甲虫与蜘蛛是两类广泛分布的功能群（guild），可提供生物防治服务。本研究在西北欧四国的66块冬小麦田中开展步甲与蜘蛛调查，分析了两类类群的活动密度与多样性如何与作物产量（土地利用强度的替代指标）、农田占比（景观复杂度的替代指标）及土壤有机碳含量相关，并探究优势种与非优势种间的上述关联模式是否存在差异。仅不足17%的步甲或蜘蛛物种被归类为优势种，但其个体数分别占总捕获量的90%以上。研究发现，步甲与蜘蛛通常与农业集约化的不同维度相关联：步甲物种丰富度与作物产量呈正相关……
本研究依托西北欧四国（德国、荷兰、瑞典与英国）的66块配对冬小麦田中的天敌群落数据，探究天敌群落对景观复杂度、局部土地利用强度及土壤有机质含量的响应，并专门检验了优势种与非优势种的响应模式是否存在差异及具体差异机制。本研究聚焦步甲与蜘蛛，因其为西北欧农田中的两类核心天敌类群，且被广泛用作生物指示物（bioindicator）（Lang等，1999；Borchard等，2014）。我们采用陷阱法（pitfall trap），在覆盖土地利用强度与景观复杂度梯度的田块配对样地中采集步甲与蜘蛛，该样地配对内的田块土壤有机碳含量存在显著差异。
本次调查使用陷阱法，即高155 mm、口径95 mm的聚丙烯烧杯，于小麦开花季（5月末至……）采集地表节肢动物。