Plant Richness, Species Assessment, and Ecology in the M'goun Geopark Rangelands, High Atlas Mountains, Morocco

Abstract

The Moroccan rangelands face significant threats, yet their species assessment and ecology remain understudied. Hence, the M'Goun Geopark was selected as a case study. Species were sampled using the stratified sampling approach combined with floristic habitat sampling. Nonparametric diversity and evenness indices were employed to estimate diversity. Subsequently, species were evaluated against IUCN status, endemism, and rarity. Detrended Correspondence Analysis (DCA) and hierarchical clustering techniques were applied to explore plant communities. Concurrently, the ecology of these rangeland communities was examined. The Geopark rangelands support exceptional biodiversity, harboring 12.03% of Morocco's plant species, totaling 509 species. The Asteraceae family is the most prominent, followed by the Fabaceae and Poaceae. The nonparametric estimator Chao 2 estimates 543.24 species, and Jackknife 1 estimates 566.48 species. In addition, the assessment revealed the precarious state of biodiversity in the Geopark. A concerning 27.73% of the assessed species are threatened according to the IUCN, and a significant portion (74.45%) lack proper evaluation. The endemism rate is 21%, with nearly half (49.5%) of these endemic species restricted solely to Morocco. Rarity criteria indicate a 17.43% rarity rate, including 8.4% considered very rare, 4.42% rare, 8.78% suspected rare, and three vulnerable. These species form 13 associations within the QUERCETEA ILICIS class, distributed across various ecological conditions and occupying elevations between 540 m and 3700 m. The bioclimate ranges from semi-arid to subhumid. Climate parameters vary considerably, with precipitation ranging from 247.13 mm to 733.83 mm, Tmin oscillating from -0.65°C to 12.69°C, and Tmax spanning between 11.42°C and 25.66°C. The associations occupy Thermomediterranean to Oromediterranean vegetation levels, particularly in limestone, clay, and sandstone substrates. Our findings reveal that these rangelands are at the epicenter of Anthropocene challenges, particularly concerning biodiversity decline, as numerous species face threats and vulnerability. Consequently, urgent conservation and monitoring plans are essential.