Landscape (dis)connectivity and river recovery: implications for river management

Geographic concerns for spatial relationships lie at the heart of geomorphic applications in river management. The way in which landscape compartments fit together in a catchment influences the operation of biophysical fluxes (i.e. transfer of water, sediment, nutrients and vegetation), and hence the ways in which disturbance responses are mediated over time. These relationships can be examined through analysis of the degree of (dis)connectivity in the landscape. There are 3 key linkages in catchments, longitudinal, lateral and vertical. The strength of these linkages changes over time, affecting the degree to which geomorphic change (and other disturbances) are either propagated or absorbed within the system. Analysis of the strength of linkages within a catchment, and detecting source areas of change, reflect system-specific attributes. However, this information provides an ideal basis for predicting from where future disturbances will be manifest. These future disturbances may be natural (e.g. a flood event) or human-induced (e.g. landuse or climate change). This provides a powerful basis upon which to predict river futures and the recovery potential of rivers at any position in a catchment. Appraisals of geomorphic river recovery potential entail determination of trajectories of change, placing reaches within their catchment context. Effective description and explanation of the history and connectivity of biophysical fluxes throughout a catchment provide a basis to identify limiting factors and pressures that will aid or hinder the future trajectory of geomorphic change and the timeframe over which recovery will occur. By gaining an understanding of the spatial, geomorphic (dis)connectivity of a catchment, patterns and rates of biophysical fluxes can be examined in a more integrative manner. Such analyses provide a rational basis for designing and implementing river management strategies, predicting river futures and prioritising where in catchments river rehabilitation will be most effective. This paper will present a range of principles that can be used to examine geomorphic (dis)connectivity in catchments, demonstrate how these principles can be used to predict river recovery potential and how this information can be used in river management practice.