Climatic Change impacts in Northern Morocco

The Rif mountain, in the northwestern part of Morocco, is a forest area of significant ecological and biological interest at both national and international levels. It has important forest diversity, with more than 20 major forest species, while a high rate of species endemism underlines its biological significance.

Forest formations, covering 35% of the region, are experiencing continuous and substantial decline due to several factors, and are currently confined mainly to the tops of mountains. The development and sustainable management of existing forests and the rehabilitation of those which have been completely lost or degraded has become a priority. To support this process, a model of the potential habitats of the main tree species is needed. 

The specific objectives of the Short Scientific Visit were to predict the potential distribution of 20 trees species in Northern Morocco. This distribution will be compared with the current distribution and subsequently with data that will be modelled using climate change projections (worldclim data).

During the visit, the potential distribution of principal species (Abies marocana, Cedrus atlantica, Quercus suber, Q. coccifera, Q.rotudifolia, and Pinus pinaster var moghrebiana) was predicted using the maximum entropy approach (Maxent). This mathematical approach is based on the estimation of a probability function that incorporates species’ bioclimatic and environmental limits while maintaining its distribution and maximum entropy. Maxent requires species presence data (but not absence), environmental data for the whole study area, and is wemap_abdelilah ghallab_250.jpg : 52.5224609375Kbll suited for modeling species distributions.

Species data collection was based on the national forest inventory and phytosociology data. Several variables on climate, topography, state of the ground surface were selected to be used as predictors for the potential distribution of different species.

To assess the coincidence between the incidence data and environmental predictors, three statistics were used: area under curve (AUC), correlation coefficient (COR), and the maximum Kappa index (κ).

The Maxent model predicted potential suitable habitat for all species with high success rates. The AUC values for all species exceed 0.8. A. marocana (figure1), C. atlantica and P. pinaster var moghrebiana, considered to be species with narrow ranges, have excellent AUC values exceeding 0.9.

Contrijacknife graph_abdelilah ghallab_250.jpg : 49.6474609375Kbbutions of environmental variables to the Maxent models showed that average annual temperature was the most important predictor of A. marocana, C. atlantica, Q.rotudifolia, and P. pinaster var moghrebiana habitat distribution; while average maximum temperature (hottest month) and lithology are the factors that most influence the distribution of Q.coccifera and Q.suber respectively.

Ghallab Abdelilah is a forest engineer preparing a thesis on Climatic Change impacts on the potential distribution of 20 trees species in Northern Morocco (12.650 km²) under the supervision of Dr. Lahcen Taiqui at the University of Abdelmalek Essaadi-Tétouan (Morocco). The EFIMED Short Scientific Visit (SSV) enabled him to work with Dr. Raul Sanchez Salguero (forest engineer) and Dr. Juan Carlos Linares Calderon from Pablo De Olavide University (Spain).

More information: Ghallab Abdelilah, ghallababdelilah (at) gmail.com

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