Data for: Rewilding soil and litter invertebrates and fungi increases decomposition rates and alters detritivore communities

Habitat degradation and associated reductions in ecosystem functions can be reversed by reintroducing or ‘rewilding’ keystone species. Rewilding projects have historically targeted restoration of processes such as grazing regimes or top-down predation effects. Few projects focus on restoring decomposition efficiency, despite the pivotal role decomposition plays in global carbon sequestration and nutrient cycling. Here, we tested whether rewilding entire communities of detritivorous invertebrates and fungi can improve litter decomposition efficiency and restore detritivore communities during ecological restoration. Rewilding was conducted by transplanting leaf litter and soil, including associated invertebrate and fungal communities from species-rich remnant sites into species-poor, and geographically isolated, revegetated farmland sites in a temperate woodland region of southeastern Australia. We compared communities in sites under the following treatments: remnant (conservation area and source of litter transplant), rewilded revegetation (revegetated farmland site with litter transplant), and control revegetation (revegetated site, no transplant). In one ‘before’ and three ‘after’ sampling periods, we measured litter decomposition and the abundance and diversity of detritivorous invertebrates and fungi. We quantified the effect of detritivores on the rate of litter decomposition using piecewise Structural Equation Modelling. Decomposition was significantly faster in rewilding sites than in both control and remnant areas, and was largely driven by a greater abundance of invertebrate detritivores. Similarly, the abundance of invertebrate detritivores in rewilding revegetation sites exceeded the level of remnant communities, whereas there was little difference between control and remnant sites. In contrast, rewilding did not increase saprotrophic fungi relative abundance/diversity and there was no strong relationship between decomposition and fungal diversity. Our findings suggest the relatively simple act of transplanting leaf litter and soil can increase functional efficiency during restoration and alter community composition. Our methods may prove important across a range of contexts where other restoration methods have failed to restore ecosystem processes to pre-degradation levels.

Methods
This dataset is part of a long term study, examining the effect of litter and soil transplants on invertebrates and microbes. To process invertebrate detritivores, we took litter samples and ran them through tullgren funnels at 3 different time points after the initial litter and soil transplants. To process fungal saprotrophs, we took soil samples in conjuction with the invertebrate samples. All steps in data processing are listed in the 'code.R' file.

栖息地退化及伴随的生态系统功能衰退，可通过重新引入关键物种（keystone species）或实施“再野化（rewilding）”予以逆转。历史上的再野化项目多聚焦于恢复放牧制度、自上而下的捕食效应等生态过程。尽管分解作用在全球碳封存与养分循环中发挥核心作用，但鲜有项目关注分解效率的修复。本研究旨在验证，重新引入食碎屑无脊椎动物（detritivorous invertebrates）与真菌的完整群落，能否在生态修复过程中提升凋落物分解效率并恢复食碎屑动物群落。本研究通过移植凋落物与土壤（包含来自物种丰富遗留样地的相关无脊椎动物与真菌群落），将其接种至澳大利亚东南部温带林地中物种贫乏且地理隔离的植被恢复农田（revegetated farmland）样地，以此实施再野化操作。我们对以下三类处理样地的群落进行了对比：遗留样地（保护区域，为凋落物移植的来源地）、实施再野化的植被恢复样地（经凋落物移植的植被恢复农田样地）以及对照植被恢复样地（未开展移植操作的植被恢复样地）。在1次前期采样与3次后期采样周期中，我们测定了凋落物分解情况，以及食碎屑无脊椎动物与真菌的丰度和多样性。我们采用分段结构方程模型（piecewise Structural Equation Modelling）量化了食碎屑动物对凋落物分解速率的影响。结果显示，再野化样地的分解速率显著快于对照样地与遗留样地，且这一差异主要由食碎屑无脊椎动物的更高丰度所驱动。类似地，实施再野化的植被恢复样地中食碎屑无脊椎动物的丰度超过了遗留样地的水平，而对照样地与遗留样地之间几乎无差异。与之相反，再野化并未提升腐生真菌（saprotrophic fungi）的相对丰度与多样性，且分解作用与真菌多样性之间未呈现显著关联。我们的研究结果表明，仅通过移植凋落物与土壤这一相对简单的操作，即可提升修复过程中的功能效率并改变群落组成。该方法或可在诸多其他修复手段未能将生态系统过程恢复至退化前水平的场景中发挥重要作用。

方法
本数据集隶属于一项长期研究，旨在探究凋落物与土壤移植对无脊椎动物及微生物的影响。针对食碎屑无脊椎动物的处理流程为：在初始凋落物与土壤移植后的3个不同时间点采集凋落物样本，通过Tullgren漏斗（Tullgren funnel）进行分离处理。为处理腐生真菌样本，我们在采集无脊椎动物样本的同时采集了土壤样本。所有数据处理步骤均已在`code.R`文件中列明。