Freshwater conservation and agriculture

Posted on September 26, 2009

Agricultural activities threaten freshwater biodiversity by causing habitat loss, pollution from chemicals and nutrients, and sedimentation as a result of soil erosion.  Governments now offer financial incentives to farmers and land managers to adopt environmentally-sensitive practices, but there have been few attempts to assess how well these measures protect aquatic species.  Since freshwater biodiversity and agriculture tend to be inversely related, it’s possible to model the conservation impacts of returning agricultural land to semi-natural habitats such as forest, woodland, grassland and wetland.  Researchers in an English study that involved the collection of data on 361 species of freshwater plants and macroinvertebrates concluded that it was possible to protect aquatic biodiversity, at a much higher level and at no extra cost, by creating areas of semi-natural habitat around targeted high-biodiversity water bodies.  This type of reserve design would extend effective protection to up to 90%  of the species surveyed, including most of the rare ones.  Costs were measured in terms of  available remuneration for the creation of buffer strips under the English Environmental Stewardship scheme.  The study was notable in that reserve design incorporated information on both species richness and the presence of rare species, and drew on data from a wide range of habitat types (lakes, ponds, ditches, rivers and streams).  Ponds were the most useful reserve elements because of their high richness and rarity value and their low costs of inclusion.

Reference:  Davies, B., Biggs, J., Williams, P. & Thompson, S.  2009.  Making agricultural landscapes more sustainable for freshwater biodiversity: a case study from southern England.  Aquatic Conservation: Marine & Freshwater Ecosystems 19, 439–447.