Abstract Debris piles and dry pools are common landscape elements along ephemeral river channels. However, their effects on resource availability and arthropod species diversity have been neglected so far. We investigated whether debris piles and pools along dry riverbeds generate nodes of environmental resources, influence microbial activity, and provide key habitats for ground-dwelling arthropods. We studied three different habitats (channel, debris pile and dry pool) to analyze organic matter, nutrients and microbial activity in dry sediments, and included two further habitats (riparian and upland areas) for ground-dwelling arthropod assemblages along a major ephemeral river (Ugab River, NW Namibia). We observed higher concentrations of organic matter and macro- and micro-nutrients in debris piles than in pools, and higher concentrations in both landscape elements than in the sandy channel matrix. Microbial activity showed a positive relationship with organic matter and nutrient availability in sediments. Debris piles, dry pools and channels harbored diverse and abundant ground-dwelling arthropod assemblages similar to adjacent terrestrial areas. Debris piles and pools differed in assemblage composition not only from riparian and upland areas but also from the sandy channel matrix. Overall, debris piles and dry pools acted as nodes of soil fertility, enhanced microbial activity, and shaped ground-dwelling arthropod assemblages.

中文翻译：

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干涸河床沿岸的垃圾堆和水池对营养物质、微生物活动和地栖节肢动物的影响：纳米比亚短暂河流的案例

摘要 泥石堆和枯水池是短暂河道沿线常见的景观要素。然而，迄今为止，它们对资源可用性和节肢动物物种多样性的影响一直被忽视。我们调查了干涸河床沿岸的垃圾堆和水池是否会产生环境资源节点、影响微生物活动并为地栖节肢动物提供关键栖息地。我们研究了三种不同的栖息地（河道、碎屑堆和干水池），以分析干沉积物中的有机质、养分和微生物活动，并包括沿主要短暂河流的地栖节肢动物组合的另外两个栖息地（河岸和高地地区）。纳米比亚西北部乌加布河）。我们观察到碎屑堆中的有机物质以及大量和微量营养素的浓度高于水池，两种景观元素的浓度都高于沙质河道基质。微生物活动与沉积物中的有机质和养分有效性呈正相关。残骸堆、干水池和水道中蕴藏着与邻近陆地区域相似的多样化和丰富的地栖节肢动物群落。碎屑堆和水池的组合组成不仅与河岸和高地地区不同，而且与沙质河道基质不同。总体而言，碎片堆和干水池充当了土壤肥力的节点，增强了微生物活动，并塑造了地栖节肢动物组合。干水池和河道拥有与邻近陆地区域相似的多样化和丰富的陆生节肢动物群落。碎屑堆和水池的组合组成不仅与河岸和高地地区不同，而且与沙质河道基质不同。总体而言，碎片堆和干水池充当了土壤肥力的节点，增强了微生物活动，并塑造了地栖节肢动物组合。干水池和河道拥有与邻近陆地区域相似的多样化和丰富的陆生节肢动物群落。碎屑堆和水池的组合组成不仅与河岸和高地地区不同，而且与沙质河道基质不同。总体而言，碎片堆和干水池充当了土壤肥力的节点，增强了微生物活动，并塑造了地栖节肢动物组合。