Analysis of root traits to test for environmental filtering and niche complementarity in grassland communities

之前的项目BE RICH基于地上特征从整个区域物种池中预测接收群落的物种表现，BE LOW将改变视角并采取新来者的视角，旨在预测新来者在当地社区的表现最好。我们将特别强调与地下过程有功能联系的性状，从而分析根系性状和渗出物，包括植物渗出物的广谱低分子有机化合物。我们将检验以下假设：（H1）生存和表现可以通过物种在特定区域内共现的统计概率来预测；（H2）群落加权平均性状和功能多样性与土地利用强度相关；（H3）叶片经济谱与根系经济谱相关。此外，我们将测试（H4），在特定的环境设置中，与居民邻里社区存在一定程度的特征相似性，在这种相似性下，绩效最大化，这是由环境过滤与限制相似性的竞争平衡造成的。此外，我们假设（H5）根系性状值和根系分泌物模式会根据当地环境和土地利用进行调整；（H6）某些根系性状值和根系分泌物会导致土壤条件随时间的变化；（H7）根系分泌物组成具有植物物种特异性，特别是禾草物种与草本物种不同。我们计划使用菌根和非菌根物种各10种，草和草本物种各10种，总共20种，在田间和温室中进行研究。对于其中的10种，我们将分析根部分泌物。该项目将包括四个工作包，包括种植植物和分析当地社区（WP1），将20个物种的植物计植入54个草地地块（3个探索，3种土地利用类型，6个重复），在最终收获时监测它们的生长并评估它们的解剖、形态和化学根系特征，并使用这些数据预测组装规则（WP2）。进行盆栽温室试验，用于根系性状分析（WP3），分析渗出液和根系，用于质谱分析非靶向代谢物（WP4）。综上所述，我们将功能生物多样性研究、群落生态学和功能根系研究结合起来，填补了地上和地下过程之间的重要空白。

While the preceding project BE RICH predicted species performance in a recipient community from the whole regional species pool based on aboveground traits, BE LOW will change the perspective and take on the newcomers' perspective, aiming at predicting in which local neighbourhood a newcomer might perform best. We will have a particular emphasis on traits with a functional link to belowground processes, and thus analyse root traits and exudates, including a broad spectrum of low molecular organic compounds exudated by plants. We will test the hypotheses that (H1) survival and performance can be predicted from the statistical probability of co-occurrence of a species in a specific local neighbourhood, (H2) community-weighted mean traits and functional diversity is related to land use intensity, (H3) the leaf economics spectrum is related to the root economics spectrum. In addition, we will test that (H4) in a specific environmental setting there is a defined degree of trait similarity to the resident neighbourhood community at which performance is maximized, caused by a balance of environmental filtering versus competition by limiting similarity. Furthermore, we hypothesize that (H5) root trait values and root exudation patterns are adjusted to the local neighbourhood and to land use, (H6) certain root trait values and exudates result in a change in soil conditions with time and (H7) that root exudate composition is plant species-specific, and in particular grass species differ from herb species. We plan to use ten species each of mycorrhizal and non-mycorrhizal species as well as ten species each of grass and herb species, in total 20 species, studied both in the field and in the greenhouse. For ten of them we will analyse root exudates. The project will consist of four work packages, which will comprise raising plants and analysis of the local neighbourhood (WP1), planting phytometers of the 20 species into a selection of 54 grassland plots (3 exploratories, 3 land use types, 6 replicates), monitoring their growth and assessing their anatomical, morphological and chemical root traits at the final harvest and using these data to predict assembly rules (WP2), conducting glasshouse experiments in pots for root trait analysis (WP3), and analyzing exudates and roots for mass spectrometry-based non-targeted metabolite analysis (WP4).In summary, we bring together functional biodiversity research, community ecology and functional root research to fill an important gap between above- and belowground processes.