The coupling of green and brown food webs regulates trophic position in a montane mammal guild
The coupling of green and brown food webs regulates trophic position in a montane mammal guild
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绿色和棕色食物网的耦合调节山地哺乳动物的营养位置
DOI：
10.1002/ecy.3949
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发表时间：
2023
期刊：
影响因子：
4.8
通讯作者：
Newsome, Seth D.
中科院分区：
文献类型：
--
作者：
Manlick, Philip J.;Cook, Joseph A.;Newsome, Seth D.
食物网生态学彻底改变了我们对生态过程的理解，但食物网的营养位置(TP)和食物链长度等特性的驱动因素是出了名的神秘。在陆地生态系统中，地上和地下系统历来被划分为“绿色”和“棕色”食物网，但动物消费者越来越认识到这些系统的耦合，这可能会对营养结构产生影响。我们使用单个氨基酸的稳定同位素分析(δ13C，δ15N)来追踪必需生物分子的流动，并联合测量一群小型哺乳动物的多渠道摄食、食物网耦合和TP。然后，我们测试了这一假设，即在微生物分解过程中，通过隐蔽的营养转移，向地上消费者传递的棕色能量增加了陆地食物链的长度。我们发现，小型哺乳动物消费者平均从棕色食物网获得近70%的必需氨基酸(69.0% ± 7.6%)，导致不同物种和功能组的TP显著增加。真菌是向地上消费者提供棕色能量的主要渠道，平均提供小型哺乳动物氨基酸预算的近一半(44.3% ± 12.0%)。这些发现说明了绿色和棕色食物网的紧密耦合性质，并表明微生物介导的能量流最终调节地上消费者的食物网结构。因此，我们认为绿色和棕色能源通道的整合是陆地生态系统食物链长度的隐秘驱动因素。
Food web ecology has revolutionized our understanding of ecological processes, but the drivers of food web properties like trophic position (TP) and food chain length are notoriously enigmatic. In terrestrial ecosystems, above‐ and belowground systems were historically compartmentalized into “green” and “brown” food webs, but the coupling of these systems by animal consumers is increasingly recognized, with potential consequences for trophic structure. We used stable isotope analysis (δ13C, δ15N) of individual amino acids to trace the flow of essential biomolecules and jointly measure multichannel feeding, food web coupling, and TP in a guild of small mammals. We then tested the hypothesis that brown energy fluxes to aboveground consumers increase terrestrial food chain length via cryptic trophic transfers during microbial decomposition. We found that the average small mammal consumer acquired nearly 70% of their essential amino acids (69.0% ± 7.6%) from brown food webs, leading to significant increases in TP across species and functional groups. Fungi were the primary conduit of brown energy to aboveground consumers, providing nearly half the amino acid budget for small mammals on average (44.3% ± 12.0%). These findings illustrate the tightly coupled nature of green and brown food webs and show that microbially mediated energy flow ultimately regulates food web structure in aboveground consumers. Consequently, we propose that the integration of green and brown energy channels is a cryptic driver of food chain length in terrestrial ecosystems.