Rebalancing the philosophy of river conservation

Abstract

Enduring themes The essential case for river conservation has been recognized for at least five decades. Here in the UK, even in the dark wartime days of 1941, a UK conference had already discussed the role of ‘nature preservation in post-war reconstruction’ (Sheail, 1995). The 1949 ‘National Parks and Access to the Countryside Act’ followed, creating the opportunity for National Nature Reserves and Sites of Special Scientific Interest (SSSIs) where ‘fauna and flora’ would be protected. In the 1970s, the Nature Conservancy Council’s Derek Ratcliffe used objective criteria to identify several British rivers that merited notification as SSSIs under what was to become the 1981 Wildlife and Countryside Act (Ratcliffe, 1977). Other nations have their own versions of these developments. By 1992, Aquatic Conservation’s current freshwater editor, Phil Boon, was able to propose that the general IUCN aims of conservation should be applied to rivers in order maintain ecological processes for life-support, preserve genetic diversity, and ensure that species and ecosystems were utilized sustainably (Boon, 1992). In the wake of pressures from habitat modification, invasive species, pollution, climate change and exploitation, and at scales ranging from the channel or river corridor to the whole catchment and beyond, he argued for a science-led approach to conservation through which the best remaining examples of river ecosystems would be preserved. Those rivers inevitably affected by human use could be safeguarded partly by management that limited or mitigated damage, and ultimately restored as far as possible. Somewhere in here was the maxim: ‘protect the best, restore the rest’. By the 1980s, the fundamental science to underpin the conservation case was well founded, and indeed has been bolstered progressively over at least 50 years. While the ecological science of rivers is now diverse and complex, the key conservation applications are relatively straightforward. First, physical, chemical and biological elements in river ecosystems interact profoundly to create their structure, dynamics and processes (Vaughan et al., 2009). Maintaining spatial variations in these factors is important to river biodiversity, as are natural variations through time associated with the hydrological cycle (Ward, 1998). Second, the character and variety of rivers is linked inextricably to the context created by the interplay among water, land and atmosphere in river catchments (Hynes, 1975). These natural units both define rivers through hydrologically defined flow-paths, and differentiate among them by forming the boundaries that have probably been critical to the divergence of organisms and the evolution of freshwater biodiversity. The conservation relevance