New horizons

Abstract This chapter looks at developments in running-water ecology and management. A suspected biodiversity crisis in running waters is driven by pollution, flow modifications, overexploitation, climate change, invasive species and other factors. Large migratory fish and mammals (the ‘megafauna’) are particularly at risk. Invasions are exacerbated by world trade and the linking of separate river catchments via artificial waterways. Emerging contaminants include pharmaceuticals, plastics and numerous industrial chemicals. Biomonitoring is adopting new (molecular) methods of assessing biodiversity, and identifies individual stressors (beyond organic wastes) and multiple stressors. Quantifying the ‘ecosystem services’ from rivers provides a basis for their conservation. Services can be provided by organisms acting as ‘ecosystem engineers’ (e.g. beavers can be part of natural flood defences). Rivers feed back on the climate by producing the greenhouse gases nitrous oxide and methane. Increasing water scarcity is the greatest threat to rivers. We briefly mention skills likely to be useful in the future.