Cyndy Loftin
John Tyler Fox
2024
<div id="ab0005" class="abstract author" lang="en"><div id="as0005"><p id="sp0040"><span>Understanding the role of hydrologic variation in structuring <a class="topic-link" title="Learn more about aquatic communities from ScienceDirect's AI-generated Topic Pages" href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/aquatic-community" data-mce-href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/aquatic-community">aquatic communities</a> is crucial for successful conservation and sustainable management of native freshwater biodiversity. Partitioning <a class="topic-link" title="Learn more about beta diversity from ScienceDirect's AI-generated Topic Pages" href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/beta-diversity" data-mce-href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/beta-diversity">beta diversity</a> into the additive components of spatial turnover and <a class="topic-link" title="Learn more about nestedness from ScienceDirect's AI-generated Topic Pages" href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/nestedness" data-mce-href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/nestedness">nestedness</a> can provide insight into the forces driving variability in fish assemblages across stream flow regimes. We examined stream fish beta diversity across hydrologic and anthropogenic disturbance gradients using long-term (1916–2016) site occurrence records (</span><i>n</i><span> = 17,375) encompassing 252 species. We assessed total beta diversity (Sørensen dissimilarity), spatial turnover, and <a class="topic-link" title="Learn more about nestedness from ScienceDirect's AI-generated Topic Pages" href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/nestedness" data-mce-href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/nestedness">nestedness</a> of fish assemblages in contrasting stream flow regimes across a gradient of decreasing flow stability: groundwater stable (</span><i>n</i> = 77), groundwater (<i>n</i> = 67), groundwater flashy (<i>n</i><span> = 175), <a class="topic-link" title="Learn more about perennial from ScienceDirect's AI-generated Topic Pages" href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/perennials" data-mce-href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/perennials">perennial</a> runoff (</span><i>n</i> = 141), runoff flashy (<i>n</i> = 255), and intermittent (<i>n</i><span> = 63) streams. Differences in total beta diversity among the stream flow regimes were driven predominantly (>86 %) by spatial turnover (i.e. species replacement) as opposed to nestedness (i.e. species loss or gain). Total fish beta diversity and spatial turnover were highest in streams with <a class="topic-link" title="Learn more about intermediate flow from ScienceDirect's AI-generated Topic Pages" href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/intermediate-flow" data-mce-href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/intermediate-flow">intermediate flow</a> stability (groundwater flashy), while more flow-stable streams (groundwater stable and groundwater) had lower turnover and higher nestedness. Species turnover was also strongly associated with seasonal variation in hydrology across all flow regimes, but these relationships were most evident for assemblages in intermittent streams. Distance-based statistical comparisons showed significant correlations between beta diversity and anthropogenic disturbance variables, including dam density, dam storage volume and water withdrawals in catchments of groundwater stable streams, while hydrologic variables were more strongly correlated with beta diversity in streams with runoff-dominated and flashy flow regimes. The high spatial turnover of species implies that fish conservation actions would benefit from watershed-focused approaches targeting multiple streams with wide spatial distribution, as opposed to simply focusing on preserving sites with the greatest number of species.</span></p></div></div><div id="ab0010" class="abstract graphical" lang="en"><br></div>
application/pdf
10.1016/j.scitotenv.2024.173825
en
Elsevier
Fish beta diversity associated with hydrologic and anthropogenic disturbance gradients in contrasting stream flow regimes
article