Belowground community turnover accelerates the decomposition of standing dead wood

Standing dead trees (snags) decompose more slowly than downed dead wood and provide critical habitat for many species. The rate at which snags fall therefore influences forest carbon dynamics and biodiversity. Fall rates correlate strongly with mean annual temperature, presumably because warmer climates facilitate faster wood decomposition and hence degradation of the structural stability of standing wood. These faster decomposition rates coincide with turnover from fungal-dominated wood decomposer communities in cooler forests to co-domination by fungi and termites in warmer regions. A key question for projecting forest dynamics is therefore whether temperature effects on wood decomposition arise primarily because warmer conditions facilitate faster decomposer metabolism, or are also influenced indirectly by belowground community turnover (e.g. termites exert additional influence beyond fungal-plus-bacterial mediated decomposition). To test between these possibilities, we simulate stan...枯立木（snags）的分解速率慢于倒卧枯木，且为诸多物种提供了关键栖息生境。因此，枯立木的倒伏速率会对森林碳动态与生物多样性产生显著影响。倒伏速率与年平均气温存在强相关性，其潜在机制为温暖气候可加速木材分解，进而降低枯立木的结构稳定性。分解速率的提升往往伴随着森林木材分解群落的更替：在气候较冷的森林中，分解群落以真菌为主导；而在温暖区域，则转变为真菌与白蚁共同主导的群落结构。因此，在预测森林动态时，一个核心科学问题在于：温度对木材分解的影响，究竟主要源于温暖环境加速了分解者的代谢活动，还是也间接受到地下群落更替的调控（例如，白蚁除了介导真菌与细菌的分解过程外，还会产生额外的调控效应）。为验证这两种可能性，我们模拟了……