Global and local drivers of the relative importance of allochthonous and autochthonous energy sources to freshwater food webs
Global and local drivers of the relative importance of allochthonous and autochthonous energy sources to freshwater food webs
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DOI：
10.1111/ecog.06612
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发表时间：
2023-01
期刊：
影响因子：
5.9
通讯作者：
Juliana S. Leal;Angélica L. González;B. Soares;Clarice Casa Nova;Nicholas A. C. Marino;V. Farjalla
中科院分区：
文献类型：
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作者：
Juliana S. Leal;Angélica L. González;B. Soares;Clarice Casa Nova;Nicholas A. C. Marino;V. Farjalla
资源量(即有机物；OM)是淡水食物网中普遍存在的能量途径的主要驱动因素。OM池主要由异地物质组成，是淡水消费者的主要资源。相比之下，少量的原生OM(即藻类)由于其较高的营养质量可以补贴水生群落。到目前为止，对于异地和原地有机质对淡水食物网的相对重要性，或者驱动它们相对重要性的环境因素，还没有达成共识。我们通过荟萃分析的方法来评估异地和原生有机质来源对全球淡水食物网的相对重要性，从而填补这一空白。我们收集了58篇已发表的研究中2789例稳定同位素混合模型的结果，并计算了淡水使用者对异地和原地有机质的平均贡献之间的响应比。使用混合效应模型和多模型推理方法，我们检验了纬度、生境类型、生态系统大小、气候和陆地生产力对响应率的影响。原生有机质在热带体系中的相对贡献率较高。在Lentium系统中，陆地生产力的增加增加了原生有机质的相对贡献，而降水和温度季节性的增加降低了这种相对贡献。我们认为，增加陆地生产力的因素也可能促进这些系统中的原生有机质，而降水则增加了异地有机质向淡水生境的输送。我们没有发现环境因素与原生有机质对生态系统的相对贡献之间的任何关系。我们的结论是，外来和本土能源对淡水食物网的相对贡献在热带生态系统和狭义生态系统中是不同的，它取决于多种环境因素。
Resource quantity (i.e. organic matter; OM) is a main driver of the prevailing energy pathway in freshwater food webs. The OM pool is mainly composed of allochthonous material, a primary resource for freshwater consumers. Contrastingly, small amounts of autochthonous OM (i.e. algae) can subsidize aquatic communities due to its higher nutritional quality. To date, there is no consensus about the relative importance of allochthonous and autochthonous OM for freshwater food webs or the environmental factors driving their relative importance. We fill this gap by evaluating the relative importance of allochthonous and autochthonous OM sources for freshwater food webs on a global scale through a meta‐analytical approach. We gathered the outcome of stable isotope mixing models of 2789 cases from 58 published studies and calculated a response ratio between the mean contributions of allochthonous and autochthonous OM for freshwater consumers. Using mixed‐effect models and a multimodel inference approach, we tested the influence of latitude, habitat type, ecosystem size, climate and terrestrial productivity over the response ratio. The relative contribution of autochthonous OM was higher in lotic systems. In lentic systems, increasing terrestrial productivity increased the relative contribution of autochthonous OM, while increasing precipitation and temperature seasonality reduced this relative contribution. We suggested that factors increasing terrestrial productivity might also boost autochthonous OM in these systems, while precipitation increases the transport of allochthonous OM to freshwater habitats. We did not find any relationship between environmental factors and the relative contribution of autochthonous OM for lotic systems. We concluded that the relative contribution of allochthonous and autochthonous energy sources to freshwater food webs differs between lotic and lentic ecosystems and it is dependent on multiple environmental factors.