Hydrology and trophic flexibility structure alpine stream food webs in the Teton Range, Wyoming, USA

Data and code necessary to replicate the findings from the manuscript titled "Hydrology and trophic flexibility structure alpine stream food webs in the Teton Range, Wyoming, USA". Abstract: Understanding biotic interactions and how they vary across habitats is important for assessing the vulnerability of communities to climate change. Receding glaciers in high mountain areas can lead to the hydrologic homogenization of streams and reduce habitat heterogeneity, which are predicted to drive declines in regional diversity and imperil endemic species. However, little is known about food web structure in alpine stream habitats, particularly among streams fed by different hydrologic sources (e.g., glaciers or snowfields). We used gut content and stable isotope analyses to characterize food web structure of alpine macroinvertebrate communities in streams fed by glaciers, subterranean ice, and seasonal snowpack in the Teton Range, Wyoming, USA. Specifically, we sought to: (1) assess community resource use among streams fed by different hydrologic sources; (2) explore how variability in resource use relates to feeding strategies; and (3) identify which environmental variables influenced resource use within communities. Average taxa diet differed among all hydrologic sources, and food webs in subterranean ice-fed streams were largely supported by the gold alga Hydrurus. This finding bolsters a hypothesis that streams fed by subterranean ice may provide key habitat for cold-water species under climate change by maintaining a longer growing season for this high-quality food resource. While a range of environmental variables associated with hydrologic source (e.g., stream temperature) were related to diet composition, hydrologic source categories explained the most variation in diet composition models. Less variable diets within versus among streams suggests high trophic flexibility, which was further supported by high levels of omnivory. This inherent trophic flexibility may bolster alpine stream communities against future changes in resource availability as the mountain cryosphere fades. Ultimately, our results expand understanding of the habitat requirements for imperiled alpine taxa while empowering predictions of their vulnerability under climate change.本数据集包含复现题为《美国怀俄明州提顿山脉水文与营养灵活性塑造高山溪流食物网》的学术手稿中各项研究结果所需的全部数据与代码。 摘要：理解生物相互作用及其随生境的变化规律，对于评估群落应对气候变化的脆弱性至关重要。高山区正在消退的冰川可导致溪流水文均质化并降低生境异质性，据预测这将推动区域多样性下降并威胁特有物种的生存。然而，学界对高山溪流生境的食物网结构，尤其是不同水文源（hydrologic sources）补给的溪流的食物网结构，仍知之甚少。 本研究采用消化道内含物分析（gut content）与稳定同位素分析（stable isotope analyses）方法，对美国怀俄明州提顿山脉内由冰川、地下冰（subterranean ice）及季节性积雪（seasonal snowpack）补给的溪流中的大型无脊椎动物群落（macroinvertebrate communities）的食物网结构进行了表征。具体研究目标包括：（1）评估不同水文源补给的溪流间的群落资源利用模式；（2）探究资源利用的差异与取食策略之间的关联；（3）明确影响群落内资源利用的环境变量。 研究结果显示，各水文源补给的溪流中类群的平均食性存在显著差异，且地下冰补给溪流的食物网主要由金色藻类Hydrurus支撑。这一发现为以下假说提供了进一步支撑：在气候变化背景下，地下冰补给的溪流可通过为该优质食物资源维持更长的生长季，为冷水物种提供关键生境。 尽管一系列与水文源相关的环境变量（如溪流水温）与食性组成相关，但在食性组成模型中，水文源类别能够解释最多的变异量。相较于溪流间的食性差异，溪流内部的食性变异程度更低，这表明类群具有较高的营养灵活性，这一结论也得到了高水平杂食性现象的进一步佐证。这种固有的营养灵活性或可帮助高山溪流群落应对未来山地冰冻圈消退带来的食物资源变动。 最终，本研究结果深化了人们对受威胁高山类群生境需求的认知，同时可为预测它们在气候变化背景下的脆弱性提供支撑。