A riverscape transect approach to studying and restoring river systems: A case study from southern China

Rivers provide critically important ecosystem services to society, and play an essential role in maintaining the structure, function, and integrity of landscapes in which the rivers reside. Better understanding of the patterns and processes in river systems requires a broader landscape approach that goes beyond the traditional linear and longitudinal focus. Such a landscape approach is especially important for effectively restoring and managing already damaged or degraded rivers around the world. Toward this end, here we develop a riverscape transect approach by adapting landscape gradient analysis with pattern metrics so as to quantify the longitudinal variations in the spatial pattern of the river-land complex from headwater to mouth. Two rivers systems in southern China were used to develop and demonstrate the approach. For each river, we first constructed a riverscape transect, consisting of a spatial series of overlapping neighborhood landscapes, then computed a selected set of landscape metrics, and finally depicted the longitudinal profile of riverscape pattern with relative location-based plots. Our results have shown that this riverscape transect approach is conceptually consistent with the increasingly prominent riverine landscape perspective and technically feasible with the aid of remote sensing data and landscape pattern analysis methods. In particular, landscape metrics, such as percentages of urban and native vegetation, patch density, and Shannon diversity, can be used to reveal important variations in riverscape structure along the river. These longitudinal profiles of riverscape pattern, used as spatial indicators, can help identify key socioeconomic drivers and ecological impacts of land use and land cover change in the watershed. Our study demonstrates that this riverscape transect approach can be a new and effective way of facilitating the planning and evaluation of river restoration and management efforts.