Nathan T. Barrus, Bryan M. Maitland, Frank J. Rahel
{"title":"Assessing a standardized method to identify optimal baselines for trophic position estimation in stable isotope studies of stream ecosystems","authors":"Nathan T. Barrus, Bryan M. Maitland, Frank J. Rahel","doi":"10.1007/s10750-024-05618-y","DOIUrl":null,"url":null,"abstract":"<p>Nitrogen stable isotope ratios (δ<sup>15</sup>N) are widely used to quantify trophic position in aquatic ecosystems. Comparing trophic position across space requires identifying baselines to account for variation in δ<sup>15</sup>N values of basal energy resources, but few standardized methods exist for identifying suitable baselines. We evaluated a standardized method for identifying optimal isotopic baselines in streams spanning the Rocky Mountains–Great Plains ecotone. We assessed candidate taxonomic groups and feeding groups following four criteria: (1) Organisms should be easy to collect and widely distributed, (2) Within-site δ<sup>15</sup>N variation should be low (representative of uniform feeding behavior), (3) δ<sup>15</sup>N values should be correlated with geographic variability in δ<sup>15</sup>N values, and (4) Trophic position of consumers calculated using the baseline should be independent of geographic δ<sup>15</sup>N variability when there is no change in diet. Simuliidae (obligate, sestonic filter feeders) met all four criteria for four fishes and produced trophic position estimates consistent with dietary changes for brown trout along a longitudinal stream gradient. The four-criteria screening method is suitable for temperate streams in North America and supports the recommendation to use Simuliidae or potentially grouped filter feeders as baseline organisms for stable isotope studies quantifying trophic position in higher-order consumers.</p>","PeriodicalId":13147,"journal":{"name":"Hydrobiologia","volume":"6 1","pages":""},"PeriodicalIF":2.2000,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Hydrobiologia","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1007/s10750-024-05618-y","RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MARINE & FRESHWATER BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Nitrogen stable isotope ratios (δ15N) are widely used to quantify trophic position in aquatic ecosystems. Comparing trophic position across space requires identifying baselines to account for variation in δ15N values of basal energy resources, but few standardized methods exist for identifying suitable baselines. We evaluated a standardized method for identifying optimal isotopic baselines in streams spanning the Rocky Mountains–Great Plains ecotone. We assessed candidate taxonomic groups and feeding groups following four criteria: (1) Organisms should be easy to collect and widely distributed, (2) Within-site δ15N variation should be low (representative of uniform feeding behavior), (3) δ15N values should be correlated with geographic variability in δ15N values, and (4) Trophic position of consumers calculated using the baseline should be independent of geographic δ15N variability when there is no change in diet. Simuliidae (obligate, sestonic filter feeders) met all four criteria for four fishes and produced trophic position estimates consistent with dietary changes for brown trout along a longitudinal stream gradient. The four-criteria screening method is suitable for temperate streams in North America and supports the recommendation to use Simuliidae or potentially grouped filter feeders as baseline organisms for stable isotope studies quantifying trophic position in higher-order consumers.
期刊介绍:
Hydrobiologia publishes original research, reviews and opinions regarding the biology of all aquatic environments, including the impact of human activities. We welcome molecular-, organism-, community- and ecosystem-level studies in contributions dealing with limnology and oceanography, including systematics and aquatic ecology. Hypothesis-driven experimental research is preferred, but also theoretical papers or articles with large descriptive content will be considered, provided they are made relevant to a broad hydrobiological audience. Applied aspects will be considered if firmly embedded in an ecological context.