Terrestrial ecosystems obtain energy in the form of carbon‐containing molecules. Quantifying energy acquisition and dissipation throughout an ecosystem may be useful for describing their resistance and resilience to disturbances. Three longleaf pine savannas with different vegetation composition—a result of variation in soil moisture and land use legacy—were used as a case study to test energy‐based metrics of ecosystem metabolic function. Available energy from gross ecosystem exchange of CO₂ and its dissipation into metabolic energy density (E_M) and energy storage were used to identify differences in drought recovery over an 8‐year period. Sites with higher plant functional diversity in the understory stored more energy and lowered their E_M by ~20% when adapting to drought. In contrast, the site with greater abundance of woody understory and overstory species relied on stored energy twice as often as the more diverse sites. The absence of native understory species, due to anthropogenic legacy, prolonged ecosystem‐scale drought recovery by 1 year. This study provides the tools to understand differences in site metabolic energy dynamics and has the potential to identify site characteristics that indicate greater vulnerability to disturbances. Metabolic energy density can be applied to any global ecosystem and provides a first step to describe coupled carbon and energy allocation in ecosystems, which may be used to further refine ecological theory and its management implications.

中文翻译：

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利用代谢能密度度量法了解干旱期间生态系统功能的差异

陆地生态系统以含碳分子的形式获取能量。量化整个生态系统中的能量获取和耗散可能有助于描述它们对干扰的抵抗力和复原力。作为案例研究，使用了三个具有不同植被组成的长叶松大草原，作为土壤水分和土地利用传统的变化的结果，以测试基于能量的生态系统代谢功能指标。生态系统中总的CO ₂交换及其散布到代谢能密度（E _M）和能量存储中的可利用能量用于确定8年期间干旱恢复的差异。下层植物功能多样性较高的场所可储存更多能量并降低其E _M适应干旱时大约减少20％。相比之下，木本林下和上林木种丰富的地点所依赖的存储能量是多样性地点的两倍。由于人为遗产的存在，当地没有林下物种，使生态系统规模的干旱恢复时间延长了一年。这项研究提供了了解场所代谢能动力学差异的工具，并有可能识别出表明更容易受到干扰的场所特征。代谢能密度可以应用于任何全球生态系统，并提供描述生态系统中碳和能量耦合分配的第一步，可用于进一步完善生态理论及其管理意义。