Species richness of trophic guilds increases with discharge and decreases with variability in tropical river fish communities

Species richness of trophic guilds increases with discharge and decreases with variability in tropical river fish communities | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 13 June 2025 V1 Latest version Share on Species richness of trophic guilds increases with discharge and decreases with variability in tropical river fish communities Authors : Colton Perna 0000-0002-2887-6309 [email protected] , David Sternberg , Mark Kennard , Osmar J. Luiz , Keller Kopf , Dylan Irvine 0000-0002-3543-6221 , and Danial Stratford 0000-0003-4185-7230 Authors Info & Affiliations https://doi.org/10.22541/au.174982164.42898552/v1 265 views 138 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Species Area Relationships (SARs) are one of the most well-established conservation biogeography patterns, and in rivers habitat area is mediated by discharge. Species richness and river discharge have a well-established positive relationship, but how discharge affects trophic diversity is less clear. Free-flowing tropical river ecosystems are hotspots of global biodiversity, but they are under increasing threat from water resource developments which alter river discharge regimes. Here we investigate relationships between river discharge metrics and the species richness of freshwater fish trophic guilds in tropical rivers of northern Australia, using data collated from 40 catchments. We analysed relationships between the species richness of freshwater fish trophic guilds and discharge metrics including mean annual discharge (Q), mean daily dry and wet season discharge and the coefficient of variation (CVQ) of Q. Invertivores and omnivores were the most species rich trophic guilds. Our results show that the species richness of trophic guilds in north Australian freshwater fishes was correlated with multiple components of wet-dry tropical river discharge regimes. The species richness of predators, invertivores and herbivore-detritivores increased with Q and wet season discharge, whereas omnivore and invertivore richness increased with dry season discharge. Increasing variability in discharge had a negative effect on the species richness of invertivores and omnivores suggesting adverse effects of low discharge periods. We found no statistical support for the hypothesis that the slope of SARs increases with trophic level as predicted by the Trophic Island Biogeography Theory. These findings suggest that decreases in wet and dry season discharge, or increases in flow variability due to water resource development or climate change, may result in the loss of trophic diversity from tropical rivers. Our results suggest that the conservation of both wet and dry season natural flow regimes in tropical rivers will be needed to protect freshwater fish trophic diversity. Supplementary Material File (discharge and trophic diversity paper_working_updated_03_06_2025.docx) Download 987.73 KB Information & Authors Information Version history V1 Version 1 13 June 2025 Copyright This work is licensed under a Non Exclusive No Reuse License. Keywords freshwater fish natural flow regime species area relationships species richness of trophic guilds trophic theory of island biogeography tropical australia Authors Affiliations Colton Perna 0000-0002-2887-6309 [email protected] Charles Darwin University View all articles by this author David Sternberg Burnett Mary Regional Group View all articles by this author Mark Kennard Griffith University View all articles by this author Osmar J. Luiz Charles Darwin University View all articles by this author Keller Kopf Charles Darwin University Faculty of Education Health and Science View all articles by this author Dylan Irvine 0000-0002-3543-6221 Charles Darwin University View all articles by this author Danial Stratford 0000-0003-4185-7230 CSIRO Land and Water View all articles by this author Metrics & Citations Metrics Article Usage 265 views 138 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Colton Perna, David Sternberg, Mark Kennard, et al. Species richness of trophic guilds increases with discharge and decreases with variability in tropical river fish communities. Authorea . 13 June 2025. DOI: https://doi.org/10.22541/au.174982164.42898552/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. 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