‘The state of river ecosystems: a degraded past, an uncertain future?’

The extent of impairment to riversystems, difficulties of restoration, and opportunities and challenges of positive management

Rivers are more than just channels for hydrological discharge, and support organisms from a diverse array of groups in the wetted channel, riparian zone and associated floodplain . Some are of clear economic importance, many are emphasised in conservation legislation, and in total river ecosystems deliver critical goods and services on which people depend throughout the world. At the same time, rivers are at risk from a wide range of pressures that arise at multiple scales. As resources, they are affected by impairments directly to the river channel (e.g. point source pollution, abstraction), by alteration of the riparian zone, and by changes in catchment land use. In this respect, they are among the most sensitive of all ecosystems to human modification, and evidence suggests that extinction rates for river organisms are at least as rapid as those in tropical rainforest.
In this lecture, Steve will offer a range of examples that illustrate the extent of impairment to river ecosystems in tropical and temperate locations, and reveal also the difficulties of restoring rivers once they are impacted: by acidification, climate change, catchment conversion to agriculture, etc. Steve will discuss the opportunities and challenges of positive management which can balance the value of rivers as resources that must inevitably be exploited, and features of major conservation importance.

Steve Ormerod is Professor of Ecology, Cardiff School of Biosciences. He is also President of the Institute of Ecology and Environmental Management, Chairman of RSPB Wales, Trustee of the RSPB, Trustee of Association of Rivers' Trusts, Trustee of South East Wales Rivers Trust
With over 25 years experience and over 220 scientific publications, Steve is one of Europe’s leading freshwater ecologists. His work focuses on large-scale, multi-disciplinary problems affecting freshwater biodiversity, ecosystem quality and function, and he is known best for flagship studies on the effects of acid rain, land use and climate-change on aquatic insects and river birds.
Landmark studies have included some of the first field-validated models of the ecological effects of acid rain, land use and climate change on river organisms. His group were among the first to develop biological indicators of river acidification and provided the world’s first evidence that birds could be affected. Investigations continue to address the problems of acid episodes in headwaters, the ecology of priority organisms, climate change effects on species and ecological function and multi-scale influences on species distribution. Key work has also included an extensive 10-year programme of assessment of resource quality in Himalayan rivers.
Steve is widely known in research and end-user communities. Current and recent positions include executive editorship of the Journal of Applied Ecology, board members of ‘Freshwater Biology’ and ‘Aquatic Conservation’, member of Council of the Freshwater Biological Association, co-ordinating peer-reviewer of Defra’s ‘Biodiversity and Agriculture Research Programme’, numerous advisory panels of the Environment Agency, Irish Environmental Protection Agency and the Institut Français de la Biodiversité. He has been a member of the Countryside Council for Wales, the UK Acid Waters Review Group (DoE), Critical Loads Advisory Group (DETR) and the National Expert Group on Transboundary Air Pollution (DETR).

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