Spatio-temporal response patterns of ecological networks to anthropogenic stressors

生态恢复在生物多样性保护中被广泛应用，以抵消生态系统的退化，减缓生物多样性的丧失。然而，恢复干预措施对支持自我维持社区的有效性很少被量化。研究人员和自然资源保护主义者的目标不是仅仅关注物种作为研究单位，而是要理解、保护和恢复生态系统的功能，这在很大程度上是通过物种之间的相互作用来维持的。了解生物相互作用对环境变化的全社区反应有助于保护管理，并根据未来土地利用和生物多样性情景预测生态系统的功能和服务。在这里，我的目标是促进对将环境威胁（如入侵物种）和这些威胁的缓解（如通过生态恢复）与生态系统功能联系起来的机制的理解，并就如何在未来生物多样性丧失的情况下维持生态系统功能（如授粉）提供预测。具体来说，两个项目组成部分中的第一个部分将研究外来物种的移除对物种之间本地互惠（授粉和种子传播）和拮抗（花蜜和花粉盗贼和种子捕食者）相互作用的长期时空响应。我将通过实验评估两种相互作用类型对本地植物适应度的净收益和损失，并通过实施多层网络方法分析它们对群落动态的直接和间接影响。第二部分将调查两种类型的社区干预措施对传粉者行为的影响：外来入侵植物的移除（恢复实验）和外来蜜蜂在植物-传粉者群落中的增加（增加实验）。我将评估在两种实验情景下，外来和本地超通才传粉者如何在传粉网络中对较少的访花者施加花资源竞争，以及对濒危植物传粉成功的贡献。为了增加我们实验方法的通用性，我将用成本和适应度函数来模拟传粉网络的相互作用动力学，以解释外来和本地传粉者之间的种内和种间竞争。从该模型得出的预测将与来自田间实验的授粉网络数据和来自同一系统的早期发表的工作交叉验证。该研究将为进一步研究环境变化对生态系统功能的影响提供基础和应用生态学知识，并有助于实施基于科学的保护管理策略，以减轻生物多样性的丧失。

Ecological restoration is employed widely in biodiversity conservation to counteract ecosystem degradation and slow the loss of diversity. Yet the efficacy of restoration interventions for supporting self-sustaining communities has rarely been quantified. Instead of focussing only on species as the unit of study, researchers and conservationists aim to understand, preserve and restore ecosystem functioning, which is largely maintained by interactions between species. Understanding community-wide responses of biotic interactions to environmental change is needed to aid conservation management and to project ecosystem functions and services to future land-use and biodiversity scenarios. Here, I aim to advance understanding of the mechanisms that link environmental threats (e.g. invasive species) and the mitigation of these threats (e.g. through ecological restoration) to ecosystem functioning, and provide predictions on how to sustain ecosystem functions (e.g. pollination) under future scenarios of biodiversity loss. Specifically, the first of two project components will address research the longer-term spatio-temporal responses of the removal of exotic species on native mutualistic (pollination and seed dispersal) and antagonistic (nectar and pollen thieves and seed predator) interactions between species. I will experimentally evaluate the net gains and losses to native plant fitness of both interaction types and analyse their direct and indirect effects on community dynamics by implementing a multilayer network approach. The second component will investigate changes in pollinator behaviour in response to two types of community-level interventions: the removal of invasive exotic plants (restoration experiment), and the augmentation of exotic honey bees in plant-pollinator communities (augmentation experiment). I will evaluate how exotic and native super-generalist pollinators exert competition for floral resources on less abundant flower-visitors in pollination networks and contribute to pollination success of endangered plants under the two experimental scenarios. To increase the generality of our experimental approach I will model interaction dynamics of pollination networks with cost and fitness functions to account for intra- and interspecific competition between exotic and native pollinators. The predictions derived from this model will be cross-validated with pollination network data from the field experiments and earlier published work from the same system. The proposed research will provide an important contribution to advancing basic and applied ecological knowledge on the impact of environmental change on ecosystem functions, and assist with implementing science-based conservation management strategies to alleviate biodiversity loss.