Intercontinental analysis of temperate steppe stream food webs reveals consistent autochthonous support of fishes
Intercontinental analysis of temperate steppe stream food webs reveals consistent autochthonous support of fishes
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DOI：
10.1111/ele.14113
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发表时间：
2022-10-12
期刊：
影响因子：
8.8
通讯作者：
Bennadji，Hayat
中科院分区：
文献类型：
--
作者：
Arsenault，Emily R.;Thorp，James H.;Bennadji，Hayat
在广泛的空间尺度上量化淡水后生动物生产的营养基础是理解生态系统功能的关键，几十年来一直是研究的重点。然而，以前的食物网研究受到地理覆盖范围或方法的限制。我们使用氨基酸（AAs）的化合物特异性稳定碳同位素分析来估计两大洲温带草原生物群落的草原，山地和半干旱生态区溪流中鱼类消费者的基础资源贡献。在一系列的流大小和光制度，我们发现一致的水生资源的营养重要性。异养微生物来源的必需氨基酸一般提供鱼类的二级支持，而陆地碳似乎没有提供显着的，直接的支持。这些发现为温带草原溪流中水生原生资源（主要）和异养微生物群落（次要）对高级消费者的碳贡献提供了强有力的证据。
Quantifying the trophic basis of production for freshwater metazoa at broad spatial scales is key to understanding ecosystem function and has been a research priority for decades. However, previous lotic food web studies have been limited by geographic coverage or methodological constraints. We used compound‐specific stable carbon isotope analysis of amino acids (AAs) to estimate basal resource contributions to fish consumers in streams spanning grassland, montane and semi‐arid ecoregions of the temperate steppe biome on two continents. Across a range of stream sizes and light regimes, we found consistent trophic importance of aquatic resources. Essential AAs of heterotrophic microbial origin generally provided secondary support for fishes, while terrestrial carbon did not seem to provide significant, direct support. These findings provide strong evidence for the dominant contribution of carbon to higher‐order consumers by aquatic autochthonous resources (primarily) and heterotrophic microbial communities (secondarily) in temperate steppe streams.