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Effects of extreme rainfall on biotic interactions in grassland ecosystems: The importance of waterlogging timing and frequency

极端降雨对草原生态系统生物相互作用的影响：涝渍时间和频率的重要性

基本信息

批准号：
259424152
负责人：
Dr. Julia Walter
金额：
--
依托单位：
Fachbereich für Wald und Umwelt
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/259424152?language=en
关键词：
Effects extreme rainfall biotic interactions

项目摘要

Extreme rainfall events and subsequent waterlogging are going to increase in frequency and duration under climate change in many parts of the world, including Central Europe. This will not only directly affect single species or individuals, but will also lead to shifts in biotic interactions and will thus feedback on plant productivity and fitness. However, knowledge about the effects of climate change on biotic interactions and specifically of waterlogging on biotic interactions is largely missing. Further, after-effects of extreme weather events on communities and interactions, as well as the role of timing of events for community response are neglected. Changes found as an immediate response can change over time, as preconditions for biotic interactions are also altered by extreme weather events. Direct effects on one particular interaction, e.g. loss of mycorrhiza may subsequently affect other biotic interactions after a time lag, e.g. herbivory or pollination. More frequent, repeated waterlogging or stress events may thus lead to totally different responses when compared to effects of a single disturbance, as they act upon already shifted biotic interactions. The timing of waterlogging events will also play a large, yet still unstudied role for ecosystem response. In a controlled mesocosm experiment incorporating a mesic grassland diversity gradient (1, 6, 9 species) and manipulating waterlogging events both in timing (spring vs. autumn) and in frequency/repetition (single vs. repeated waterlogging) I aim to i) investigate the effects of waterlogging on plants and plant communities and on biotic interactions (plant-decomposer, plant-pollinator, plant-mycorrhiza, plant-herbivore, plant-pathogen and plant-plant interactions)ii) disentangle direct effects of waterlogging on single actor from effects mediated by shifts in plant leaf qualityiii) assess the longevity of shifts in biotic interactions and possible feedback on primary production, herbivory, decomposition and community composition and diversityiv) study the role of timing of waterlogging for system response and compare the response towards single vs. repeated waterlogging eventsIn the proposed project, numerous biotic interactions will be assessed simultaneously and over several growing seasons, comparing effects of spring vs. autumn waterlogging and comparing effects of single vs. repeated waterlogging. Mesic grassland is chosen as study system, because of its great agricultural importance in Central Europe and because it might be prone to more intense waterlogging in the future, but is currently not adapted to extreme waterlogging. The overall aim is to identify drivers of ecosystem response towards stress in biotic interactions (e.g. which interactions are resilient and which not, or which changes in interactions amplify or buffer effects over a longer time-period) and to investigate cascading of effects over interaction levels and over time.

在包括中欧在内的世界许多地区，极端降雨事件和随后的内涝将在气候变化的情况下增加频率和持续时间。这不仅会直接影响单个物种或个体，还会导致生物相互作用的变化，从而对植物的生产力和适应性产生反馈。然而，关于气候变化对生物相互作用的影响，特别是涝渍对生物相互作用的影响的知识在很大程度上是缺失的。此外，极端天气事件对社区和相互作用的后续影响，以及事件发生的时间对社区反应的作用也被忽视。作为即时反应的变化可能会随着时间的推移而变化，因为生物相互作用的先决条件也会因极端天气事件而改变。对一种特定相互作用的直接影响，例如菌根的丧失，可能在一段时间后影响其他生物相互作用，例如植食性或授粉。因此，与单一干扰的影响相比，更频繁、重复的内涝或胁迫事件可能导致完全不同的反应，因为它们作用于已经改变的生物相互作用。水涝事件发生的时间也将对生态系统的反应起到很大的作用，但尚未得到研究。在一个控制的中尺度生态系统实验中，（1，6，9种）和操纵涝渍事件的时间（春季与秋季）和频率/重复（单次与重复的水涝）我的目标是i）调查水涝对植物和植物群落以及生物相互作用的影响（植物分解者，植物授粉者，植物菌根，植物食草动物，植物-病原体和植物-植物的相互作用）ii）从植物叶片质量变化介导的影响中分离出淹水对单个因素的直接影响iii）评估生物相互作用变化的持久性以及对初级生产、草食动物、分解和群落组成和多样性的可能反馈iv）研究涝渍发生的时间对系统响应的作用，并比较对单一涝渍事件和重复涝渍事件的响应在拟议的项目中，将在几个生长季节内同时评估多种生物相互作用，比较春季和秋季涝渍的影响，并比较单次涝渍和多次涝渍的影响。梅西奇草原被选为研究系统，因为它在中欧农业的重要性，因为它可能会在未来更激烈的水涝，但目前不适应极端水涝。总体目标是确定生态系统对生物相互作用中的压力作出反应的驱动因素（例如，哪些相互作用具有弹性，哪些没有弹性，或者相互作用的哪些变化在较长时间内放大或缓冲效应），并调查相互作用水平和时间的级联效应。