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

恢复河段的自然水文地貌条件，旨在改善河流动物群。然而，这些恢复措施中有几项未能恢复预期的近自然社区。与此同时，在德国的地表水中经常检测到几种杀虫剂，这可能会限制敏感的、对栖息地要求很高的底栖无脊椎动物物种的重新定居。这项建议旨在开发两个针对应激源的指标，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，正在进行的监测计划中的农药浓度将被转换为毒性压力的量度，并与有效的水形态参数一起使用，以得出地点的“应激源概况”。同时，我们将考虑景观的恢复潜力，并考虑到来源人口。为了将结果转移到没有农药测量的地点，将应用基于地理信息系统的地表径流模型来估计农药投入量。最后，一个空间上明确的“重新定居潜力”模型将通过实地调查得到验证，它将允许确定影响底栖无脊椎动物物种当前分布和潜在重新定居的驱动力。

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.