Grassland parasites and community dynamics under climate change

全球变暖正在影响范围广泛的生物，包括动植物的寄生虫。然而，大多数关于气候变化的生物效应的研究都考虑了生理过程和单一物种的反应，尽管已知物种间的相互作用在群落水平上强烈影响气候变化的结果。这一限制可能会破坏对寄生虫未来对自然和农业生态系统影响的预测。该项目将调查草原-土壤群落中的关联物种如何受到气候变化的影响，以及物种之间的相互作用如何影响结果。这将加强对气候变化对放牧系统生产力和恢复力影响的认识。该项目将重点研究线虫，这是食草牲畜和草本身的主要寄生虫。随着抗虫性的增强，农业正在寻求更全面的战略来减轻感染压力，而这些将受益于更好地了解寄生虫传播的生态环境。该项目的具体目的是研究生物相互作用如何改变线虫寄生虫在不同草原群落中的传播。这将通过结合mesocosms，改变原位环境实验和预测建模来解决。一旦确定了关键的相互作用，该项目将调查它们在气候变化下如何受到影响。温度和湿度等非生物因素的影响将在其直接影响（如寄生虫热响应）和通过群落相互作用的间接影响中得到考虑。一般的方法将是：(i)校准每个功能群中关键物种的热响应曲线（包括植物-寄生和动物-寄生线虫，草和食草动物）；（ii）比较曲线并确定在高温情景下的“赢家和输家”；（iii）运行动态模型，比较季节变化的气候和气候变化下的结果。关于这些群体的气候依赖性的现有数据将作为模型校准和验证的基础，并在必要时辅以额外的实验。在校准之后，将根据基线和暖场条件下物种响应的纵向数据对模型进行测试和验证。工作将主要基于贝尔法斯特女王大学和CASE合作伙伴，农业食品和生物科学研究所（AFBI）。项目结果将加强对生态群落中不同物种之间的热反应的影响如何被它们之间的联系所改变的理解，从而确定对生态系统功能的净影响。产出将说明对气候变化的非线性反应可能如何影响自然和管理的草地系统。模型敏感性分析将绘制出系统内关键物种的反应和脆弱性，并支持对未来研究领域进行合理的优先排序。情景分析将从天然草地系统的稳定性和生产力以及畜牧场的合理适应性管理等方面探讨可能的应对措施。通过该模型和不同气候带种群间的响应曲线比较，还可以探讨寄生虫适应变暖的后果。该项目对农业具有潜在的好处，为设计更可持续和更有弹性的放牧系统寄生虫控制提供了基础。减轻对线虫化学处理的依赖将减缓抗药性的发展，并有望为农民提供其他控制选择。这将有利于消费者，因为它有助于提供负担得起的食品，同时减少对环境的影响。

Global warming is affecting a wide range of organisms, including parasites of plants and animals. Most studies of the biological effects of climate change, however, consider physiological processes and single species responses, despite the fact that inter-species interactions are known to strongly influence outcomes of climate change at community level. This limitation could undermine predictions of future impacts of parasites on natural and agricultural ecosystems. This project will investigate how linked species in grassland-soil communities are affected by climate change, and how outcomes are influenced by interactions between species. This will enhance understanding of the effects of climate change on grazing system productivity and resilience. The project will focus on nematodes, which are major parasites of grazing livestock, and of grass itself. With rising anthelminthic resistance, the agricultural industry is looking towards more holistic strategies to alleviate infection pressure, and these will benefit from better understanding of the ecological context of parasite transmission.The specific aims of this project are to investigate how biotic interactions alter nematode parasite transmission in different grassland communities. This will be addressed using a combination of mesocosms, altered in situ environment experiments, and predictive modelling. Once key interactions have been determined, the project will investigate how they are affected under climate change. The impact of abiotic factors such as temperature and moisture will be considered in both their direct impacts, such as parasite thermal responses, and their indirect impacts through community interactions.The general approach will be to: (i) calibrate thermal response curves for key species in each functional group (including plant-parasitic and animal-parasitic nematodes, grass, and grazers); (ii) compare curves and identify 'winners and losers' under elevated temperature scenarios; and (iii) run dynamic models to compare outcomes under seasonally varying climates and climate change. Existing data on the climate-dependence of these groups will underpin model calibration and validation, complemented by additional experiments as needed. Following calibration, models will be tested and validated against longitudinal data on species responses under baseline and warmed field conditions. Work will be based primarily at Queen's University Belfast and CASE partners, the Agri-Food and Biosciences Institute (AFBI).Project results will enhance understanding of how the effects of different thermal responses among species in ecological communities are modified by the linkages between them to determine net impacts on ecosystem function. Outputs will illustrate how non-linear responses to climate change might affect natural and managed grassland systems. Model sensitivity analysis will map key species responses and vulnerabilities within the system, and support rational prioritisation of areas for future research. Scenario analysis will explore likely responses in terms of the stability and productivity of natural grassland systems, and rational adaptive management on livestock farms. Consequences of parasite adaptation to warming could also be explored through the model, and response curves compared among populations from different climatic zones.This project has potential benefits for the agricultural industry, by underpinning the design of more sustainable and resilient parasite control in grazing systems. Alleviation of reliance on chemical treatment of nematodes would slowing the development of resistance and hopefully provide alternative control options for farmers. This will benefit consumers, by helping to provide affordable food with decreased environmental impacts.