The argan tree is exclusively endemic in the drylands of Southwest Morocco, an agroecosystem of great ecological, cultural, and economic importance. The argan agroecosystem is already damaged. It is particularly vulnerable to climate change as well as the harsh natural conditions aggravated by the current population growth and the exploitation in excess of the production capacities. Unfortunately, during the 20th century, its area has been reduced by half. Current projections indicate an increase in temperature under climate scenarios. Anticipated climate change could accelerate this trend resulting in the argan tree degradation. To assess the climate change impact, the authors used the SDSM model at the argan agroecosystem scale and the thermal stress model to assess its vulnerability and estimate its tolerance response in relation to temperature stress for a projected climate in the near term (2010-2025 years). In this chapter, the authors explored the impact of climate change on the argan tree regeneration.
TopIntroduction
The arganeraie (argan agroecosystem) includes an important rate of biodiversity offering many ecosystem services (Karmaoui, 2016). Various parts of the argan tree are globally used from traditional medicine for common human and animal ailments (Aabd et al., 2014). The traditional health care was scientifically validated (Charrouf & Guillaume, 2010).
In the last 30 years, this arganeraie is among the most vulnerable ecosystems of the arid and semi-arid lands. In regard to argan area, it lost almost 9900 hectares, an average of 550 ha/year between the years of 1969-1986, the Argan plain lost (EL Yousfi, 1988). In Haha region (western High Atlas) for example, de-densification was estimated to 600 ha per year (Bouzemouri, 2007). The decline in the argan area is attributed to both the lack of regrowth and loss of trees (De Waroux & Lambin, 2012). Currently, this ecosystem continues to be destroyed with all its components of biodiversity (El Mrabet et al., 2014). It has been exploited as firewood, timber, as forage for goats and sheep (Alados, 2008). Increasing aridity reported at a regional-scale by Esper et al., (2007). In fact, increasing aridity may be attributed to climate change (Nouaim, 2005). Climate change causes more droughts and more heat in the argan region, making the argan tree less adapted (Lybbert et al., 2011). During drought years the amount of surface water may drop 20 times (SIWM, 2001). This decrease may influence argan primary production. Consequently, climatic stress can be a key risk factor that accelerates degradation produced by the local population.
This chapter aims:
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To assess the climate change impact, the Statistical Downscaling Model (SDSM) was used at argan agroecosystem scale.
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To explore the thermal stress for a projected climate in near term (2010-2025) using a thermal stress model.
Because of climate change, large areas of argan groves could then be created on other continents in regions most appropriate to the argan tree (Lybbert et al., 2011). The study designed to look at the relationship between climate change and the argan regeneration. The authors look to confirm or refute this affirmation basing on modeling methods.
TopMaterials And Methods
Study Area
This study was carried out on the Argan Biosphere Reserve in south east of Morocco, with a geographical area of 950 000 ha, the most part was located in the Souss-Massa region before 2015 (Figure 1). This biome was classified as UNESCO Biosphere Reserve in 1998 (El Benni & Reviron, 2009).
Figure 1. Overview of the argan biome in south east of Morocco: Land cover