Spiders have gained wide acceptance in ecological studies as indicators of environmental quality because they show a strong preference for habitat type and pattern of land use. Knowledge of the spider community in Neotropical landscapes is still incipient. In order to decrease such lack of knowledge, this study provides information on the ground-dwelling spider assemblages in remnants of native Brazilian Cerrado (savanna woodlands) and in exotic pastures (Urochloa spp.; Poaceae). We collected the spiders in two remnants of native vegetation and in four exotic pastures using pitfall traps in Aquidauana, Mato Grosso do Sul, Midwestern Brazil. A total of 141 adults were captured, belonging to 11 families and 22 species of spiders (Arachnida: Araneae). Sixteen species were found in the exotic pastures, 10 in the Brazilian Cerrado, and only four were common to both habitats. We found higher species richness in exotic pastures when compared to Brazilian Cerrado. In addition, four spider species were reported for the first time in the state of Mato Grosso do Sul: Apopyllus silvestrii (Simon, 1905) (Gnaphosidae) sampled in exotic pastures, and Eilica rufithorax (Simon, 1893) (Gnaphosidae), Lycosa inornata Blackwall, 1862 (Lycosidae) and Oxyopes salticus (Hentz, 1845) (Oxyopidae) captured in the remnants of native vegetation. With these results, we minimize the Wallacean shortfall by increasing knowledge on distribution of spiders in remnants of native Cerrado and exotic pastures in the Midwestern Brazil. Moreover, we demonstrate that the ground-dwelling spider assemblage is rich and abundant in exotic pastures, a structurally poor and homogeneous habitat compared to the native vegetation of the Brazilian Cerrado. Then, our findings may aid in understanding the complexity of effects generated by mixed ecosystems on this group of predatory arthropods widely used as bioindicators of environmental and land use changes.

中文翻译：

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最大限度地减少华莱士的短缺：一个小样本揭示了在巴西中西部本土塞拉多和异国情调的牧场新出现的地栖蜘蛛

蜘蛛作为环境质量的指标在生态研究中得到了广泛认可，因为它们对栖息地类型和土地利用模式表现出强烈的偏好。对新热带地区蜘蛛群落的了解仍处于起步阶段。为了减少这种知识的缺乏，本研究提供了有关巴西本土塞拉多（稀树草原林地）和外来牧场（Urochloa spp.；禾本科）残余物中地栖蜘蛛组合的信息。我们在巴西中西部南马托格罗索州的 Aquidauana 使用陷阱陷阱在两个原生植被残余和四个异国牧场中收集了蜘蛛。共捕获141只成虫，分属11科22种蜘蛛（Arachnida：Araneae）。在异国情调的牧场中发现了 16 种，巴西塞拉多有 10 种，并且只有四个是两个栖息地共有的。与巴西塞拉多相比，我们发现外来牧场的物种丰富度更高。此外，南马托格罗索州首次报道了四种蜘蛛物种：Apopyllus silvestrii (Simon, 1905) (Gnaphosidae) 在外来牧场取样，以及 Eilica rufithorax (Simon, 1893) (Gnaphosidae), Lycosa inornata Blackwall, 1862 (Lycosidae) 和 Oxyopes salticus (Hentz, 1845) (Oxyopidae) 在原生植被的残余物中捕获。有了这些结果，我们通过增加对蜘蛛在巴西中西部本土塞拉多和异国牧场的残余中分布的了解，最大限度地减少了华莱士的短缺。此外，我们证明了地栖蜘蛛组合在异国情调的牧场中丰富而丰富，与巴西塞拉多的原生植被相比，这是一个结构较差且均质的栖息地。然后，我们的发现可能有助于理解混合生态系统对这组广泛用作环境和土地利用变化的生物指标的掠食性节肢动物产生的影响的复杂性。