Aberdeen Institute for Coastal Science and Management
Abstract
Climate change scenarios for NW Scotland and the Western Isles envisage a combination of rising sea level, increased
winter precipitation, and increased frequency and severity of winter storms. The flat, low-lying machair lands of the
Uists are thus particularly vulnerable, not only from marine overtopping of coastal dune ridges, but also from inland
flooding and restricted drainage, which may enhance the duration and area of seasonal standing waters within the
machair lands. The drainage network of the Uist machairs is a legacy of historic drainage of a more extensive loch
network, which now forms an intricately balanced complex of linked water bodies exhibiting a wide range of pH
and salinity. Any future change in water levels would impose significant environmental shifts. The conservation importance
of machair is significantly augmented by a pattern of rotational cultivation that largely employs traditional
methods and provides species-rich fallows. This tradition is already under economic threat, and increased flooding
could have far-reaching consequences for both agriculture and wildlife. The Uist machair systems have a range of
inter-dependent, multiple-interest international conservation designations and the vulnerability of these is examined
in a context that incorporates the vital human dimension
