The hyporheic zone (HZ) of streams harbors co-occurring epigean taxa and stygobionts (including HZ specialist taxa and deeper groundwater taxa) that face the same set of local environmental factors, but are derived from spatially and functionally discrete colonist pools. We investigate whether occurrences of epigean taxa and stygobionts are differentially influenced by the same set of environmental variables in HZ samples from Texas, USA. We increase the number of records for described stygobionts in the state by nearly 12%, but 26 stygobionts (35%) were undescribed species. Stygobionts had smaller average ranges (3549 km2) than epigean taxa (24,046 km2), but occurred in similar abundances. Dissolved oxygen and temperature influenced community composition in both groups, but stygobiont community composition, richness, and abundance were influenced by association with karst aquifers and surface water-groundwater exchange, whereas epigean taxa composition was only weakly influenced by the association with karst aquifers. Contrasts between epigean taxa and stygobiont occurrence patterns are primarily explained by differences in range size, dispersal ability, and the pool of potential colonizer species. This first documentation of Texas HZ communities includes 14 stygobionts previously recorded only from karst aquifers: their discovery in the HZ has important management implications.

中文翻译：

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环境对美国德克萨斯州低流带交错带中无脊椎动物多样性和群落组成的影响：同时发生的表生类群和尾生生物之间的对比

溪流的潜流带 (HZ) 包含共同发生的表生类群和尾流生物（包括 HZ 专业类群和更深的地下水类群），它们面临着相同的局部环境因素，但来自空间和功能上离散的殖民者池。我们调查了来自美国德克萨斯州的 HZ 样本中表观分类群和 stygobionts 的发生是否受到同一组环境变量的不同影响。我们将州内已描述的 stygobionts 的记录数量增加了近 12%，但 26 个 stygobionts (35%) 是未描述的物种。Stygobionts 的平均范围（3549 平方公里）比表层类群（24,046 平方公里）小，但它们的丰度相似。溶解氧和温度影响了两组的群落组成，但 stygobiont 群落组成、丰富度、和丰度受与岩溶含水层的关联和地表水-地下水交换的影响，而表层分类群组成仅受与岩溶含水层的关联影响很小。Epigean 分类群和 stygobiont 发生模式之间的对比主要是由范围大小、传播能力和潜在殖民者物种库的差异来解释的。德克萨斯州 HZ 社区的第一份文件包括 14 种先前仅从岩溶含水层记录的 stygobiont：它们在 HZ 中的发现具有重要的管理意义。Epigean 分类群和 stygobiont 发生模式之间的对比主要是由范围大小、传播能力和潜在殖民者物种库的差异来解释的。德克萨斯州 HZ 社区的第一份文件包括 14 种先前仅从岩溶含水层记录的 stygobiont：它们在 HZ 中的发现具有重要的管理意义。Epigean 分类群和 stygobiont 发生模式之间的对比主要是由范围大小、传播能力和潜在殖民者物种库的差异来解释的。德克萨斯州 HZ 社区的第一份文件包括 14 种先前仅从岩溶含水层记录的 stygobiont：它们在 HZ 中的发现具有重要的管理意义。