Published online by Cambridge University Press: 16 June 2020
Fresh waters are not amenable to protection by fortress conservation, since entire drainage basins can seldom be set aside. Site selection by conservation modelling has shortcomings because of the directional connectivity of river ecosystems. In the many cases where habitat degradation is the primary threat to freshwater biodiversity, restoration measures (that include riparia) may ameliorate matters, allowing species persistence or even recovery. However, rehabilitation is often the best that can be achieved. Mitigation of the barrier effects of dams by fishways have limited effectiveness, but complete removal of dams is an effective means of restoring connectivity. Ex situ (captive breeding, reintroduction, translocation) and in situ conservation measures – sometimes in combination – have been applied to a variety of freshwater animals, using new techniques such as eDNA for monitoring. Various international networks have been established recently to facilitate collaboration on conservation and improve data collection and sharing. There are thus reasons to be hopeful – rather than optimistic – about the prospects for preserving freshwater biodiversity in a warming world.