Modelling resilient species for the restoration of the Green Dam in Algeria

Abstract

Algeria has long suffered from ongoing desertification, resulting in the progressive loss of vegetation and soil erosion. This has had a severe impact on rural livelihoods in the north, making local communities more vulnerable and causing a decline in biodiversity. In an attempt to counter these trends, the Green Dam initiative was launched to establish a forest belt to mitigate desertification in the arid zone from east to west across Algeria. Unfortunately the project has faced failures as monocultures of P. halepensis Mill. experienced parasitic outbreaks and struggled to grow. Our study aimed to identify alternative tree species suitable for the climatic conditions in northern Algeria. We evaluated 20 woody species native to North Africa, projecting their potential distributions using MaxEnt 3.4 software under the current climate and two future climate scenarios (SSP 370, SSP 585). The environmental data was collected from the CHELSA database and the Shared Socioeconomic Pathway 3.70 and 5.85 were used. Based on these projections, we partitioned the Green Dam into three regions, Southern, Eastern and Northern. The regions were delineated by species predicted to perform well under both current and future conditions. We recommend two species for afforestation across the entire Green Dam: Juniperus oxycedrus L. and Pistacia lentiscus L. A risk assessment indicated that the Green Dam region is highly susceptible to wildfire due to elevated temperatures and low precipitation. Given these conditions, we also recommend planting Pistacia atlantica Desf. (Atlas pistachio), a species with reduced flammability. Incorporating the Atlas pistachio alongside region-specific species is expected to enhance habitat diversity and reduce overall wildfire risk.