Deforestation and land-use change in tropical regions result in habitat loss and extinction of species that are unable to adapt to the conditions in agricultural landscapes. If the associated loss of functional diversity is not compensated by species colonizing the converted habitats, extinctions might be followed by a reduction or loss of ecosystem functions including biological control. To date, little is known on how land-use change in the tropics alters the functional diversity of invertebrate predators and which key environmental factors may mitigate the decline in functional diversity and predation in litter and soil communities. We applied litter sieving and heat extraction to study ground spider communities and assessed structural characteristics of vegetation and parameters of litter in rainforest and agricultural land-use systems (jungle rubber, rubber and oil palm monocultures) in a Southeast Asian hotspot of rainforest conversion: Sumatra, Indonesia. We found that (1) spider density, species richness, functional diversity and community predation (energy flux to spiders) were reduced by 57-98% from rainforest to oil palm monoculture; (2) jungle rubber and rubber monoculture sustained relatively high diversity and predation in ground spiders, but small cryptic spider species strongly declined; (3) high species turnover compensated losses of some functional trait combinations, but did not compensate for the overall loss of functional diversity and predation per unit area; (4) spider diversity was related to habitat structure such as amount of litter, understory density and understory height, while spider predation was better explained by plant diversity. Management practices that increase habitat structural complexity and plant diversity such as mulching, reduced weeding, and intercropping monocultures with other plants may contribute to maintaining functional diversity of and predation services provided by ground invertebrate communities in plantations.

中文翻译：

---

热带土地利用变化下栖息地结构退化导致地蜘蛛群落功能丧失

热带地区的森林砍伐和土地利用变化导致无法适应农业景观条件的物种栖息地丧失和灭绝。如果相关的功能多样性丧失没有通过在转换栖息地中定居的物种来补偿，那么灭绝之后可能会导致生态系统功能的减少或丧失，包括生物控制。迄今为止，人们对热带地区的土地利用变化如何改变无脊椎动物捕食者的功能多样性以及哪些关键环境因素可能减轻凋落物和土壤群落功能多样性和捕食性的下降知之甚少。我们应用凋落物筛分和热提取来研究地蜘蛛群落，并评估了东南亚热带雨林转化热点：苏门答腊的热带雨林和农业土地利用系统（丛林橡胶、橡胶和油棕单一栽培）中植被的结构特征和凋落物参数，印度尼西亚。我们发现（1）从雨林到油棕单一栽培，蜘蛛密度、物种丰富度、功能多样性和群落捕食（对蜘蛛的能量通量）降低了 57-98%；(2)丛林橡胶和橡胶单一栽培在地蜘蛛中保持了较高的多样性和捕食性，但小型隐蔽蜘蛛种类急剧减少；(3) 高物种周转补偿了一些功能性状组合的损失，但没有弥补单位面积功能多样性和捕食性的整体损失；(4) 蜘蛛多样性与凋落物数量、林下密度和林下高度等生境结构有关，而蜘蛛捕食可以用植物多样性更好地解释。增加栖息地结构复杂性和植物多样性的管理实践，例如覆盖、减少除草和与其他植物间作单一栽培，可能有助于维持人工林地面无脊椎动物群落的功能多样性和捕食服务。