MODÉLISATION DE LA DISTRIBUTION SPATIALE DES PARAMÈTRES BIOCLIMATIQUES DANS LA REGION TANGERTETOUAN (RIF OCCIDENTAL)

This work focuses on mapping the main bioclimatic factors in the region of Tangier -Tetouan (western Rif) in Morocco. This is with the view of integrating them into the modeling of the potential distribution of native plant species. These factors include the Annual Mean precipitation (Pmoy), Annual Mean Temperature (Tmoy), mean maximum temperature of the hottest month (Tmin), and the mean minimum temperature of the coldest month (Tmax). The adopted technique is the statistical modeling, which allows us to estimate such factors based on topographic and geographic variables. The backward stepwise multiple regression method which was applied, and the deterministic models obtained, have been corrected by the stochastic components that were interpolated by the Inverse Distance Weighting (IDW). The results of this modeling are discussed in the light of the results of other works of the same theme, as compared to previous descriptions of the climatic environment in the area. The results are satisfactory in the case of the average annual precipitation, mean annual temperature, and the mean minimum temperature of the coldest month, with coefficients of determination (R²) of 0,76, 0,97 and 0,74, respectively. However, this ratio reached its lowest value (0,55) for the average of the maximum temperature of the warmest month. The assessment of the accuracy of the results obtained for the mean annual precipitation and mean annual temperatures was performed by calculating the Mean Absolute Error (MAE) and the Root Mean Squared Error (RMSE). These tests have shown that stochastic components contribute significantly to the improvement of deterministic model

Characterizing spatial structure of Abies marocana forest through point pattern analysis

Aim of study: Understanding small-scale patterns caused by stochastic factors or community interactions driving forest structure and diversity of Moroccan fir Abies marocana Trab.Area of study: Talassemtane fir forest, Talassemtane National Park, Rif Mountains, northern Morocco.Material and methods: Eight plots representative of the structural variability of A. marocana forests were selected, and all tree individuals with diameter at breast height (dbh) ≥2 cm were mapped and measured. We performed four types of spatial point pattern analyses: (1) Univariate analyses to explore the overall trees spatial pattern, (2) bivariate analyses to assess the spatial relationship between juveniles and A. marocana adults, (3) correlation between tree sizes (dbh) and distance between points pairs using the univariate mark correlation function, and (4) random labeling analyses between dominant and suppressed Moroccan fir individuals to assess competition patterns.Main results: We found a strong spatial aggregation of fir individuals and a positive intraspecific association between juveniles and adult trees. However, there were weak but significant distance-dependent effect on tree size and density-dependent effect on suppression pattern.Research highlights: Shade-tolerance, seed dispersal and/or microsite heterogeneity might play important roles in the observed fir patterns. Our results provide a basic knowledge on within-stand Moroccan fir spatial distribution, with implications for adaptive management of these relic forests, and prompting to further research to test advanced hypotheses.Additional key words: Moroccan fir; Talassemtane National Park; Rif forest; Spatial analysis; summary statistics; facilitation; aggregation.Abbreviations used: MF (Moroccan fir); Talassemtane National Park (TNP); dbh (diameter at breast height); Univariate pair-correlation function (g(r)); Heterogeneous Poisson (HP); Bivariate pair-correlation function (g12(r)); Univariate mark correlation function (kmm(r)), Mark connection function (p12(r))

Spatio-temporal analysis and identification of deforestation hotspots in the Moroccan western Rif

In the north of Morocco, forest areas are under threat mainly due to the expansion of agricultural land, forest fires and socio-demographic, economic and urban dynamics. Despite the magnitude of deforestation in this area, quantitative studies and investigations of its evolution in time and space are rare or non-existent. The present study aims to assess and quantify gross forest losses in the Western Rif between 2001 and 2020 through the exploitation of Global Forest Change (GFC) data developed by Hansen et al. (version 1.8) based on high resolution Landsat TM satellite images. We used Local Indicators of Spatial Association (LISA) methods to identify statistically significant spatio-temporal trends in forest losses with ArcGis 10.8 and Geoda software. The main results showed that over the last two decades, the Western Rif has lost 8.39% of its forest heritage, a total area of 272 km2. The greatest forest losses were recorded in the provinces of Chefchaouen, Tetouan and Larache (70% of total losses), while the highest annual deforestation rates are reported in the prefectures of M'diq-Fnideq and Tangier-Assilah (0.9% and 0.89% respectively). Moreover, we observed that 81% of the deforested areas were recorded in the formations of the following types: matorral, cork oak stands and artificial pine forest. A first analysis of local Moran's spatial autocorrelation based on the communal division and on the variables relating to forest losses and gross deforestation rates revealed the existence of 3 significant clusters of the high-high (HH) type. A second optimized analysis of deforestation hotspot (Getis-Ord statistical test) based on a 0.5 km × 0.5 km grid identified 26 deforestation fronts in the study area. Finally, we conducted an emerging hotspot analysis to take into account the time dimension and we concluded that the oscillating deforestation model predominates in the Western Rif. These results constitute valuable decision elements to better guide, prioritize and rationalize the monitoring, conservation and restoration efforts of forest ecosystems

Detecting Fire-Caused Forest Loss in a Moroccan Protected Area

Fire is a concern for the sustainability of dry forests such as those of the Mediterranean region, especially under warming climate and high human use. We used data derived from Landsat and MODIS sensors to assess forest changes in the Talassemtane National Park (TNP) in North Africa from 2003–2018. The Talassemtane National Park is a protected area in northern Morocco, a biodiverse, mountainous region with endemic species of concern such as the Moroccan fir (Abies marocana) and Barbary macaque (Macaca sylvanus). To help the managers of the TNP better understand how the forest has been impacted by fire vs. other disturbances, we combined information from remotely derived datasets. The Hansen Global Forest Change (GFC) data are a global resource providing annual forest change, but without specifying the causes of change. We compared the GFC data to MODIS wildfire data from Andela’s Global Fire Atlas (GFA), a new global tool to identify fire locations and progression. We also analyzed surface reflectance-corrected Landsat imagery to calculate fire severity and vegetation death using Relative Differenced Normalized Burn Ratio analysis (RdNBR). In the park, GFC data showed a net loss of 1695 ha over 16 years, corresponding to an approximately 0.3% annual loss of forest. The GFA identified nine large fires that covered 4440 ha in the study period, coinciding with 833 ha of forest loss in the same period. Within these fires, detailed image analysis showed that GFA fire boundaries were approximately correct, providing the first quantitative test of GFA accuracy outside North America. High-severity fire, as determined by RdNBR analysis, made up about 32% of burned area. Overall, the GFA was validated as a useful management tool with only one non-detected wildfire in the study period; wildfires were linked to approximately 49% of the forest loss. This information helps managers develop conservation strategies based on reliable data about forest threats

Detecting Fire-Caused Forest Loss in a Moroccan Protected Area

Fire is a concern for the sustainability of dry forests such as those of the Mediterranean region, especially under warming climate and high human use. We used data derived from Landsat and MODIS sensors to assess forest changes in the Talassemtane National Park (TNP) in North Africa from 2003–2018. The Talassemtane National Park is a protected area in northern Morocco, a biodiverse, mountainous region with endemic species of concern such as the Moroccan fir (Abies marocana) and Barbary macaque (Macaca sylvanus). To help the managers of the TNP better understand how the forest has been impacted by fire vs. other disturbances, we combined information from remotely derived datasets. The Hansen Global Forest Change (GFC) data are a global resource providing annual forest change, but without specifying the causes of change. We compared the GFC data to MODIS wildfire data from Andela’s Global Fire Atlas (GFA), a new global tool to identify fire locations and progression. We also analyzed surface reflectance-corrected Landsat imagery to calculate fire severity and vegetation death using Relative Differenced Normalized Burn Ratio analysis (RdNBR). In the park, GFC data showed a net loss of 1695 ha over 16 years, corresponding to an approximately 0.3% annual loss of forest. The GFA identified nine large fires that covered 4440 ha in the study period, coinciding with 833 ha of forest loss in the same period. Within these fires, detailed image analysis showed that GFA fire boundaries were approximately correct, providing the first quantitative test of GFA accuracy outside North America. High-severity fire, as determined by RdNBR analysis, made up about 32% of burned area. Overall, the GFA was validated as a useful management tool with only one non-detected wildfire in the study period; wildfires were linked to approximately 49% of the forest loss. This information helps managers develop conservation strategies based on reliable data about forest threats

Characterizing spatial structure of Abies marocana forest through point pattern analysis

Aim of study: Understanding small-scale patterns caused by stochastic factors or community interactions driving forest structure and diversity of Moroccan fir Abies marocana Trab. Area of study: Talassemtane fir forest, Talassemtane National Park, Rif Mountains, northern Morocco. Material and methods: Eight plots representative of the structural variability of A. marocana forests were selected, and all tree individuals with diameter at breast height (dbh) ≥2 cm were mapped and measured. We performed four types of spatial point pattern analyses: (1) Univariate analyses to explore the overall trees spatial pattern, (2) bivariate analyses to assess the spatial relationship between juveniles and A. marocana adults, (3) correlation between tree sizes (dbh) and distance between points pairs using the univariate mark correlation function, and (4) random labeling analyses between dominant and suppressed Moroccan fir individuals to assess competition patterns. Main results: We found a strong spatial aggregation of fir individuals and a positive intraspecific association between juveniles and adult trees. However, there were weak but significant distance-dependent effect on tree size and density-dependent effect on suppression pattern. Research highlights: Shade-tolerance, seed dispersal and/or microsite heterogeneity might play important roles in the observed fir patterns. Our results provide a basic knowledge on within-stand Moroccan fir spatial distribution, with implications for adaptive management of these relic forests, and prompting to further research to test advanced hypotheses

Caractérisation d’un périmètre de reboisement de pinède en vue de proposition des essences les plus appropriées, cas du Jbel Zemzem (Nord-ouest, Maroc)

La dégradation accélérée des forêts est un défi majeur pour les gestionnaires. Le reboisement constitue alors une solution importante pour l’amélioration des services écosystémiques voire la survie des écosystèmes. Comparée à d’autres essences comme l’Eucalyptus, les pins renferment une biodiversité plus élevée. Nous avons étudié la phytodiversité d’un périmètre de reboisement avec quatre espèces et deux variétés de pins (Pinus halepensis, P. pinaster var. maghrebiana et var iberica, P. pinea et P. canariensis) afin de proposer l’essence la plus convenable au reboisement. Sur les 38 relevés floristiques réalisés, 83 espèces ont été recensées appartenant à 34 familles. Les valeurs de l’indice de diversité étaient maximales dans les plantations de P. halepensis et P. pinea et minimales dans celles de P. canariensis. L’ordination multidimensionnel non métrique et la Classification Ascendante Hiérarchique ont montré trois groupes : groupe à P. halepensis et P. pinea, groupe à P. maghrebiana et Quercus suber et groupe à P. iberica et P. canariensis. P. halepensis et P. pinea ont montré un cortège floristique relativement riche mais avec un appauvrissement structurel comparé à la subéraie originale. Il ressort que le reboisement à base de P. maghrebiana et dans une deuxième place P. halepensis améliore la structure des peuplements et présente un potentiel important pour la gestion des reboisements au nord du Maroc