New approaches: Use of assisted natural succession in revegetation of inhabited arid drylands as alternative to large-scale afforestation

Abstract

AbstractIt is a great concept to let nature do the work of revegetation, however in semi-arid and arid regions the process of natural succession, if it occurs at all, typically requires many years of undisturbed development until an increase in biomass becomes measurable, hence it rather is applied to remote, sparsely populated regions and may be underrated as a measure to restore native vegetation, particularly in inhabited arid areas. What are the factors that make arid successional processes successful, how to expedite, and how to enable their use for the ecological revegetation of densely populated drylands? We review restoration methods that combine the planting of shelterbelt compartments with successional revegetation of the internal area, protected from wind and drought. Various measures of assisted natural succession can be applied to greatly accelerate the revegetation, including soil tillage, amendment with organic matter and the inoculation with cyanobacteria or lichens to form biocrusts. The aim is to initiate the development of native, water-saving savanna with biodiversity, resilience and adaptability to climate change. A narrow twin shelterbelt module could facilitate the use of natural succession within inhabited and peri-urban areas, also serving as protective greenbelt for cities. A pilot is planned in a peri-urban area of Northern Iraq, with a successional area of 125–150 m between shelterbelts. Land-use of agriculture, gardening and recreation can be integrated within the successional area, which also generates engagement of residents in the maintenance work. Planting of shelterbelts is required on 10–25% (not 100%) of the restoration area, therefore the use of assisted succession within protective compartments is expected to have both, ecological and economic advantages over large-scale afforestation.