Plastic responses to hot temperatures homogenize riparian leaf litter, speed decomposition, and reduce detritivores
Plastic responses to hot temperatures homogenize riparian leaf litter, speed decomposition, and reduce detritivores
复制标题
塑料对高温的反应使河岸落叶层均质化，加速分解并减少食碎物
DOI：
10.1002/ecy.3461
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发表时间：
2021
期刊：
影响因子：
4.8
通讯作者：
Whitham, Thomas G.
中科院分区：
文献类型：
--
作者：
Jeplawy, Joann R.;Cooper, Hillary F.;Marks, Jane;Lindroth, Richard L.;Andrews, Morgan I.;Compson, Zacchaeus G.;Gehring, Catherine;Hultine, Kevin R.;Grady, Kevin;Whitham, Thomas G.
在气候变化下维持关键生态系统功能的努力往往开始于基础物种。在美国西南部，三角叶棉白杨树支持受到气温上升威胁的河岸生态系统中的各种社区。三角叶杨内的遗传变异塑造了群落和生态系统，但这些影响可能会被表型可塑性所改变，即基因型性状会因环境条件而改变。在这里，我们研究了弗里蒙特棉白杨（Populus fremontii）落叶特征的可塑性以及可塑性对河岸生态系统的影响。我们使用了三个普通的花园，每个花园都种植了来自六个遗传上不同的种群的基因型，跨越12°C的温度梯度，并在一个共同的溪流环境中进行分解实验。我们发现，叶凋落物面积，比叶面积和碳氮比（C：N）的遗传和生长环境之间的相互作用，是随后的凋落物分解率。落叶性状的遗传变异大多出现在不同气候历史的源种群之间，而不是源种群内。来自较热气候的源种群通常产生分解更快的垃圾，但可塑性改变了这种影响的大小。我们还发现，较热的生长条件减少了不同基因型间产生的凋落物性状的变异，减少了对河岸生态系统的凋落物输入。所有基因型在最热的花园产生相对较小的叶子，分解迅速，支持较低丰度的水生无脊椎动物，而相同的基因型在最冷的花园产生不同的形态和分解率的垃圾。我们的研究结果表明，对气候压力的塑料反应可能会以可预测的方式限制遗传变异的表达，从而影响社区和生态系统。了解遗传和环境变化之间的相互作用对于我们在变暖的世界中管理和恢复河岸生态系统时规划基础物种的作用至关重要。
Efforts to maintain the function of critical ecosystems under climate change often begin with foundation species. In the southwestern United States, cottonwood trees support diverse communities in riparian ecosystems that are threatened by rising temperatures. Genetic variation within cottonwoods shapes communities and ecosystems, but these effects may be modified by phenotypic plasticity, where genotype traits change in response to environmental conditions. Here, we investigated plasticity in Fremont cottonwood (Populus fremontii) leaf litter traits as well as the consequences of plasticity for riparian ecosystems. We used three common gardens each planted with genotypes from six genetically divergent populations spanning a 12°C temperature gradient, and a decomposition experiment in a common stream environment. We found that leaf litter area, specific leaf area, and carbon to nitrogen ratio (C:N) were determined by interactions between genetics and growing environment, as was the subsequent rate of litter decomposition. Most of the genetic variation in leaf litter traits appeared among rather than within source populations with distinct climate histories. Source populations from hotter climates generally produced litter that decomposed more quickly, but plasticity varied the magnitude of this effect. We also found that hotter growing conditions reduced the variation in litter traits produced across genotypes, homogenizing the litter inputs to riparian ecosystems. All genotypes in the hottest garden produced comparatively small leaves that decomposed quickly and supported lower abundances of aquatic invertebrates, whereas the same genotypes in the coldest garden produced litter with distinct morphologies and decomposition rates. Our results suggest that plastic responses to climate stress may constrict the expression of genetic variation in predictable ways that impact communities and ecosystems. Understanding these interactions between genetic and environmental variation is critical to our ability to plan for the role of foundation species when managing and restoring riparian ecosystems in a warming world.