Revegetation of steeplands in France and New Zealand: Geomorphic and policy responses

Abstract

Background: Efforts to address erosion and land degradation in steeplands of many countries have largely relied on revegetation. The policy responses to this issue are many and varied as have been their successes. Revegetation efforts tend to occur when it is realised that deforestation, mountain land erosion, and flooding of rivers are linked. Methods: Using the Southern Prealps region in France and the East Coast North Island region of New Zealand as 'study sites', past and current revegetation efforts to address steepland degradation were compared. Results: Both areas have similarities in geology, geomorphology and types of erosion processes (shallow landsliding and gullying). Landscape responses to large-scale erosion and subsequent reforestation have been similar between France and New Zealand though major reforestation occurred in France more than a century before that in New Zealand. Attempts to control sediment production in headwater regions reinforces the view that conditions controlling the evolution of channel response (through time and space) to a change in sediment supply are complex. While there is a consistent sequence of responses in channels and on hillslopes to reforestation efforts and the direction of changes may be anticipated, the magnitude and timing of those responses are not. Conclusion: The key lesson for future management and policy development arising from these studies is that erosion-control efforts that are aimed at producing basin-scale impacts will require targeting of areas where the proposed land use change or intervention will have the most beneficial influence on reducing sediment supply to river channels. © 2013 Phillips et al.