Wood decomposition and decomposer interactions

更广泛的研究背景：更高的树木多样性可能通过增加枯木的多样性和森林的异质性而有利于腐植型昆虫。通过为物种在落叶或土壤中觅食提供食物和筑巢空间，枯木是连接地上和地下食物网的重要纽带。假设：在BEF-中国实验中，我们建议沿着树木多样性梯度研究腐生型昆虫群落。我们的主要假设是：(1)树木多样性与枯木数量和多样性呈正相关，(2)腐植酸类昆虫群落的功能性状多样性增加。(3)腐生型昆虫群落功能性状多样性越高，乔木多样性越高，对木材分解有正向影响。(4)由于小气候和昆虫群落垂直分层的差异，悬浮枯木的分解速度慢于地面。方法：我们将表征所有核心样地中自然发生的枯木的数量和多样性，以评估腐植酸昆虫(WP1)的资源质量和可用性。我们将从所有核心地块的枯木中确定腐植酸昆虫群落的功能和分类多样性。对于蚂蚁和白蚁，我们将通过落叶和陷阱(SP3和SP6)评估物种池，因为在地块内存在捕食性蚂蚁可能会阻止其他昆虫在枯木上定居(WP2)。在VIP地块中，我们将展示来自四个不同树种的枯木，并允许昆虫定居或排除昆虫。我们将根据木材特性确定腐植酸昆虫群落的特征，并测量木材质量损失(WP3)。此外，我们将比较悬浮枯木和暴露在地面上的木片在有和没有昆虫排除的情况下的木材分解和腐氧昆虫的定植(WP4)。创新：我们将扩展之前的工作，将树木多样性作为腐氧昆虫群落的驱动因素和必然的分解过程。我们将把树木多样性对分解者群落的直接影响从影响当地物种库的环境变化的间接影响中分离出来，从而改变枯木中的群落组装过程或分解者与其他营养水平的生物之间的相互作用。主要研究人员参与：该项目将由Heike Feldhaar(Pi，Uni Bayreuth)和Simon Thorn(Co-Pi，Uni Würzburg)与我们的中国合作伙伴Arong Luo(中国科学院)合作进行。

Feldhaar & ThornWood decomposition and decomposer interactions (SP1)Wider research context: Higher tree diversity may be beneficial to saproxylic insects by enhancing the diversity of dead wood and forest heterogeneity. By providing food and nesting space for species foraging in leaf-litter or soil, dead wood is an important link between the above- and below-ground food web.Hypotheses: Here, we propose to study saproxylic insect communities along a tree diversity gradient in the BEF-China experiment. Our main hypotheses are: (1) Tree diversity is positively correlated to the amount and diversity of dead wood, which (2) leads to an increase in (functional trait) diversity of saproxylic insect communities. (3) Higher functional trait diversity of saproxylic insect communities with increasing tree diversity has a positive effect on wood decomposition. (4) Decomposition of suspended dead wood is slower than on the ground due to differences in microclimate and vertical stratification of insect communities.Methods: We will characterize the amount and diversity of naturally occurring dead wood in all core plots to assess resource quality and availability for saproxylic insects (WP1). We will characterize the functional and taxonomic diversity of saproxylic insect communities from dead wood in all core plots. For ants and termites, we will assess species pools from leaf litter and pitfall traps (with SP3 and SP6) since the presence of predatory ants within plots may prevent other insects from colonising dead wood (WP2). In the VIP plots we will expose dead wood from four different tree species and either allow insect colonization or exclude insects. We will characterize saproxylic insect communities in relation to wood traits and will measure wood mass loss (WP3). Moreover, we will compare wood decomposition and colonization by saproxylic insects of suspended dead wood with pieces exposed on the ground, again with and without insect exclusion (WP4).Innovation: We will extend previous work by including tree diversity as a driver of saproxylic insect communities and the entailing decomposition process. We will disentangle the direct effects of tree diversity on decomposer communities from indirect effects mediated through environmental changes affecting the local species pool, thereby altering community assembly processes in dead wood or interactions between decomposers and organisms of other trophic levels.Primary researchers involved: This project will be conducted by Heike Feldhaar (PI, Uni Bayreuth) and Simon Thorn (Co-PI, Uni Würzburg), in collaboration with our Chinese partner Arong Luo (Chinese Academy of Sciences).