Collembola (Arthropoda) communities of forest ecosystems in Changbai Mountain, northeast China: Trophic structure, changes with altitude and response to increased temperature

弹尾虫是数量最多、种类最多的土壤动物之一，对土壤分解和养分循环等主要生态系统过程有重要贡献。全球温度和降水的变化可能会影响它们的群落结构和功能，这可能会在海拔梯度上有所不同。本项目以长白山地区沿海拔梯度的森林生态系统弹线虫群落为研究对象。旨在研究(1)沿800 ~ 1850 m高度样带弹线虫群落结构的变化；(2)沿这些高度样带弹线虫营养结构的变化；(3)利用群落系统发育学研究弹线虫群落的聚集机制；(4)弹线虫群落对模拟21世纪气温升高的实验变暖的响应。线虫群落结构将基于沿3个复制的垂直样带在150 m的高度间隔取样线虫，并确定线虫的种/形态种。将利用稳定同位素特征的自然变化和脂质分析来研究弹弹的营养结构。作为群落系统发育的基础，将利用一组标记对弹尾虫物种进行测序，从而量化当地物种的遗传关系。物种的特征将被绘制到系统发育树上，以评估系统发育信号，并允许识别负责群落组成随海拔变化的特征。通过模拟温度升高2°C和4°C，在田间实验室土芯中进行全因子实验，研究线虫对温度升高的响应，考察线虫群落结构、营养生态位和性状分布的变化。总体而言，本研究旨在利用弹线虫作为模型土壤生物，确定在广泛的环境条件下土壤动物群落组装过程的特征，从而确定驱动这些变化的机制，并允许预测土壤动物群落随全球温度变化的变化。

Collembola (sprintails) are among the most abundant and diverse soil animals contributing significantly to major ecosystem processes such as decomposition and nutrient cycling. Global changes in temperature and precipitation are likely to affect their community structure and functioning and this is likely to differ along altitudinal gradients. The project focuses on Collembola communities of forest ecosystems along altitudinal gradients in northeastern China (Changbai Mountain). It aims at investigating (1) changes in the community structure of Collembola along altitudinal transects spanning from about 800 to 1850 m, (2) changes in the trophic structure of Collembola along these altitudinal transects, (3) assembly mechanisms of Collembola communities using community phylogenetics, and (4) the response of Collembola communities to experimental warming simulating an increase in temperature predicted to occur in the 21st century. Community structure of Collembola will be based on sampling Collembola along three replicated altitudinal transects at hight intervals of 150 m and determining Collembola to species / morphospecies. The trophic structure of Collembola will be investigated using natural variations in stable isotope signatures and lipid analysis. As basis for using community phylogenetics, Collembola species will be sequenced using a set of markers allowing to quantify genetic relationships of local species. Traits of species will be mapped on the phylogenetic tree to evaluate phylogenetic signal and allow to identify traits responsible for changes in community composition with altitude. The response of Collembola to increased temperature will be investigated in a full factorial experiment incubating in the laboratory soil cores taken in the field by simulating an increase in temperature of 2°C and 4°C, and inspecting changes in community structure, trophic niches and trait distribution of Collembola species. Overall, the study aims at using Collembola as model soil organisms for identifying traits responsible for soil animal community assembly processes across a wide range of environmental conditions, thereby identifying the mechanisms driving these changes and allowing to predict changes in soil animal communities with global temperature changes.