Management of cumulative risk in the Pasvik river ecosystem Mitigating the impact of climate change and human activities on fish populations

Abstract

The cumulative risk of climate change, pollution and other anthropogenic stressors challenges the sustainable management of freshwater ecosystems. Rapid warming at high latitudes is of concern due to the climate-driven amplification of risk mediated by interactions between the climate change and human activities. Here I address the cumulative risk in the subarctic Pasvik riverine system exposed to the combined effects of climate change, heavy metal pollution from local industrial activity, hydropower, and fisheries. Further, I evaluate the potential and limitations in the existing management regime and strategy to mitigate cumulative risk to the ecosystem. The cumulative risk assessment is based on a review of relevant data and literature, with particular focus on risk for fish species. The evaluation of management is based on existing reports and literature and direct experience of the management practice in Pasvik. I find substantial scope for direct and indirect impact of multiple anthropogenic stressors in Pasvik. Further, I identify interactions between climate change and respectively fishery, mercury pollution and hydropower activities. The management regime dictated by the water framework directive, and the local management practice in Pasvik, are presently not adequate to address the cumulative risk imposed by climate change and other anthropogenic stressors, and possible solutions for cumulative risk mitigation are suggested.