The role of long-term landscape photography as a tool in dune management

Abstract

Attitudes to maintaining dune diversity are changing under the realization that existing dune stabilization techniques are fixing dune landscapes, causing ‘coastal squeeze’ and loss of habitat as shorelines retreat. Instead, it is recommended that a natural, dynamic, migrating dune system is much more appropriate and that blown, unstable sands are encouraged to act as mobile coastal defence barriers. Lack of appropriate monitoring techniques has limited progress in understanding the role of sediment dynamics in dune environments over long timescales. Therefore, this paper outlines the role of straightforward and inexpensive photography, from fixed points and angles, as a useful approach to long-term, decadal monitoring of the evolution and migration of dynamic dune landforms. The case study, on the Morfa Dyffryn dunes, Gwynedd, mid-Wales, United Kingdom (National Grid Reference SH563240), identified particularly dynamic mobile foredunes, with cyclical morphological development, paralleling to an overall landward recession. A cyclical trend of sand encroachment, followed by stabilization with growing vegetation, is documented for semi-fixed dune pastures, while the hind dunes remained stable. A general relationship between foredune morphology and erosion/accretion processes was established, offering the prospect of predicting future dune morphological changes in other dune systems, if increased blown sand activity is encouraged as a management technique.