Ecological targeting toolkit. WP 2.3: ecological recovery potential

Mitigation and intervention measures delivered by AES aim to improve the physico-chemical conditions of streams and rivers impacted by agricultural practices. Outcomes consist principally of nutrient and sediment reductions in run-off, and preventing degradation of the riparian habitat. However, chemical and physical improvements do not necessarily guarantee recolonisation by the flora and fauna, though these are central to achieving the desired ecological quality and conservation status. For recolonisation to occur, the biota must disperse from other aquatic habitats in the surrounding landscape to the restored site. The dispersal abilities of different biota are a main determinant of site recolonisation, but the process is also dependent on habitat connectivity, biogeographic history and barriers to dispersal (natural such as mountains, or anthropogenic such as dams). The recolonisation process will be more rapid and more complete the closer a site is to pools of colonists, which are reaches on the same or a nearby waterbody where physicochemical conditions support diverse ecological communities, such as sites at good and high WFD ecological status.