Ground spiders can reflect the impacts of land-use intensification. In an integrated annual crop-livestock system, the grazing intensification can negatively influence the abundance and richness of ground spiders. We evaluated the difference in abundance, family and species richness, and species composition of ground spiders in the soybean and pasture environments, and the effect of grazing intensity on the spider community under a soybean-pasture rotation. We hypothesized that pastures would have higher spider species richness and a distinct species composition and that the increase in grazing intensity would reduce spider abundance and species richness. We conducted an experiment in an integrated annual crop-livestock system under a soybean-pasture rotation in southern Brazil that was managed for 14 years by alternating Glycine max for summer grain production and Avena strigosa + Lolium multiflorum for beef cattle grazing during the winter. We sampled four times over 2 years: twice after the grazing cycles and twice after the soybean harvests. Grazing intensification was measured as grazing heights of 10, 20, 30, and 40 cm. Pitfall traps were installed to capture ground spiders. A total of 2589 spiders were collected and classified into 23 families and 43 species. The abundance of spiders was seven times higher, and species richness was 35% higher in the postgrazing compared with the postsoybean environment. Linear mixed effects models showed that spider abundance and richness were strongly influenced by grazing height, particularly postgrazing, but the influence of grazing height on male spider abundance could still be detected in the postsoybean environment. We have shown for the first time that the management of grazing height affects the abundance and richness of spiders in an integrated annual crop-livestock system. To introduce a grazing cycle to a completely crop-centric production system and regulating grazing intensity can help maintain a more diverse spider community.

中文翻译：

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牧场中放牧强度的提高降低了农作物-畜牧综合系统中地面蜘蛛的丰度和丰富度

地面蜘蛛可以反映出土地利用集约化的影响。在一个完整的年度农牧系统中，放牧集约化会对地面蜘蛛的丰度和丰富度产生负面影响。我们评估了大豆和牧草环境中地面蜘蛛的丰度，家庭和物种丰富度以及物种组成的差异，以及在大豆草场旋转下放牧强度对蜘蛛群落的影响。我们假设牧场具有更高的蜘蛛物种丰富度和独特的物种组成，放牧强度的提高会降低蜘蛛的丰度和物种丰富度。我们在巴西南部的大豆草场轮作下，在一个年度农作物-畜牧综合系统中进行了一项试验，该试验通过交替耕种管理了14年用于夏季谷物生产的最大大豆和Avera strigosa +黑麦草冬季放牧的肉牛。我们在2年中进行了四次采样：放牧周期后两次，大豆收获后两次。放牧强度的测量高度为10、20、30和40 cm。安装了陷阱陷阱以捕获地面蜘蛛。总共收集了2589只蜘蛛，分为23个科目和43种。与放牧后的环境相比，放牧后蜘蛛的丰度高出七倍，物种丰富度高出35％。线性混合效应模型表明，放牧高度特别是后放牧对蜘蛛的丰度和丰富度有强烈影响，但在大豆后环境中仍可检测到放牧高度对雄性蜘蛛丰度的影响。我们第一次表明，放牧高度的管理会在年度综合作物－牲畜系统中影响蜘蛛的丰度和丰富度。将放牧周期引入完全以作物为中心的生产系统并调节放牧强度可以帮助维持更多样化的蜘蛛群落。