SP7: Interactions between saproxylic insects and consequences for wood decomposition

枯木分解在养分循环中起着重要作用。在热带地区，昆虫对枯木的分解起了很大作用。在这里，主要是白蚁、甲虫和蚂蚁与真菌在复杂的相互作用中驱动腐烂过程。到目前为止，这些生物间的相互作用还没有被很好地理解。但是，由于热带森林的退化影响到分解生物的多样性和丰度，分解过程也应受到影响。这些群落在枯木中的复原力以及在热带森林恢复期间这些群落重新组合的潜力尚不清楚。在这里，我们的目标是研究木材的腐烂及其殖民者沿着森林恢复梯度，从牧场到次生林再到原始热带森林，首先采用调查方法，其次采用实验方法，在实验方法中，我们监测沿着森林恢复梯度的小块中布置的枯木的重组过程。最后，我们将沿着完全恢复梯度进行排除实验，以理清土壤扰动作为森林内部退化的一种类型，以及不同分类群（白蚁、蚂蚁、甲虫）对分解过程的贡献及其相互作用。在我们的方法中，我们将使用网络方法分析社区重组模式。我们将在宿主物种、真菌、白蚁、甲虫和蚂蚁之间建立几个网络，并确定调节相互作用的物种特征。具体而言，我们的目标是表征腐殖酸群落对森林退化的响应，分析人为干扰后腐殖酸群落复杂网络的重组，并量化腐殖酸群落及其生物相互作用对热带雨林森林恢复梯度分解率的影响。

Dead wood decomposition plays an important role in nutrient cycling. In the tropics, insect contribute greatly to dead wood decomposition. Here predominantly termites, beetles and ants together with fungi drive the decay process in complex interactions. These biotic interactions are not well understood so far. However, since the degradation of tropical forests affects the diversity and abundance of decomposing organisms, the decomposition process should be affected as well. The resilience of these communities in dead wood as well as the potential of reassemby of these communities during recovery of tropical forests is unknown. Here, we aim to investigate the decay of wood and its colonizers along a forest recovery gradient from pastures to secondary forests to primary tropical forests, first in a survey approach and second in an experimental approach where we monitor reassembly processes of dead wood laid out in plots along the forest recovery gradient. Finally, disentangle the effects of soil disturbance as one type of forest interior degradation, the contribution of different taxa (termites, ants, beetles) and their interactions, on the decomposition process, we will conduct an exclusion experiment along the full recovery gradient. In our approaches, we will analyse community reassembly patterns using a network apporach. We will create several networks between host species, fungi, termites, beetles and ants together with the identification of species traits modulating the interactions. Specifically, we aim to characterize the responses of saproxylic communities to forest degradation, to analyse the reassembly of complex networks of saproxylic communities following anthropogenic disturbance, and to quantify the effect of saproxylic communities and their biotic interactions on decomposition rates along the forest recovery gradient in a tropical rainforest.