Interrelation between pesticide inputs, hydromorphology and source populations influencing the recolonization of benthic invertebrate communities

恢复河段自然水文形态条件的目的是改善河流动物群。然而，其中一些恢复措施未能恢复预期的接近自然的群落。与此同时，在德国地表水中经常检测到几种杀虫剂，这可能会限制敏感的、需要栖息地的底栖无脊椎动物物种的重新定居。本研究旨在建立两种胁迫因子特异性指标，以区分农药投入和形态退化对大型无脊椎动物群落的影响。为此，正在进行的监测项目中的农药浓度将被转换为毒性应激的测量指标，并与有效的水文形态参数一起使用，以得出位点的“应激源剖面”。同时，考虑到源种群，我们将考虑景观的恢复潜力。为了将结果转移到没有农药测量的地点，将应用基于gis的地表径流模型来估计农药投入的大小。最后，一个空间明确的“再定殖潜力”模型，将通过实地调查验证，将允许确定影响底栖无脊椎动物物种当前分布和潜在再定殖的驱动力。

The restoration of natural hydromorphological conditions of stream sections aims to improve the riverine fauna. Yet, several of these restoration measures failed to rehabilitate the expected near-natural communities. At the same time, several pesticides are frequently detected in German surface waters that may limit the recolonisation of sensitive, habitat-demanding benthic invertebrate species. This proposal aims to develop two stressor-specific indicators to distinguish between the impacts of pesticide inputs and morphological degradation on macroinvertebrate communities. For this purpose, pesticide concentrations from an ongoing monitoring program will be converted to a measure of toxic stress and used together with effective hydromorphological parameters to derive a 'stressor profile' of sites. Concurrently we will consider the recovery potential of the landscape, taking source populations into account. To transfer the results to sites where no pesticide measurements are available, a GIS-based surface runoff model will be applied to estimate the magnitude of pesticide inputs. Finally, a spatially-explicit 'recolonization potential' model, which will be validated by field investigations, will allow to identify the driving forces affecting the current distribution and potential recolonisation of benthic invertebrate species.