Riparian habitat in the southwestern United States has undergone substantial degradation over the past century, prompting extensive management and restoration of these critical ecosystems. Most restoration efforts, however, do not account for life history traits or riverine complexity that may influence genetic diversity and structure. Here, we use simple sequence repeat markers in four southwestern riparian species (Populus fremontii, Salix gooddingii, S. exigua, and Prosopis glandulosa) that occupy a geographically complex region to address four questions: (1) How is river connectivity related to genetic diversity and structure? (2) How do mating systems and dispersal mechanisms influence gene flow? (3) Is genetic diversity influenced by unidirectional water flow? (4) How do unregulated tributary and regulated river flows affect clonality and associated diversity? Our results identify five findings: (1) Patterns of genetic diversity and structure vary substantially across different species; (2) species with geographic distributions that include a large, perennial river exhibit the least genetic structure; (3) mating system, clonality, and seed dispersal are related to genetic structure; (4) genetic diversity is variable among species and populations, but does not increase or decrease unidirectionally; and (5) clonality and associated diversity does not differ along a regulated river relative to unregulated tributaries. Our multispecies approach to understanding how riverine complexity and life history traits influence genetic diversity and structure could be incorporated into management efforts to more closely match riparian species with their unique environments, thereby facilitating restoration success.

中文翻译：

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河流的复杂性和生活史为美国西南部河岸环境的恢复提供了信息

在过去的一个世纪里，美国西南部的河岸栖息地经历了严重的退化，促使对这些关键生态系统进行了广泛的管理和恢复。然而，大多数恢复工作并未考虑可能影响遗传多样性和结构的生活史特征或河流复杂性。在这里，我们在四种西南河岸物种（Populus fremontii、Salix gooddingii、S. exigua和Prosopis gearulosa）中使用简单序列重复标记) 占据地理复杂区域以解决四个问题：(1) 河流连通性如何与遗传多样性和结构相关？(2) 交配系统和传播机制如何影响基因流动？(3) 单向水流是否影响遗传多样性？(4) 不受管制的支流和受管制的河流流量如何影响克隆性和相关的多样性？我们的结果确定了五个发现：（1）不同物种的遗传多样性和结构模式差异很大；(2) 地理分布包括一条大型多年生河流的物种，其遗传结构最少；(3) 交配系统、无性系、种子传播与遗传结构有关；(4) 遗传多样性在物种和种群之间是可变的，但不会单向增加或减少；(5) 相对于不受管制的支流，受管制河流的克隆性和相关多样性没有差异。我们了解河流复杂性和生活史特征如何影响遗传多样性和结构的多物种方法可以纳入管理工作，使河岸物种与其独特的环境更紧密地匹配，从而促进恢复成功。