An evaluation and inventory study on the natural vegetation cover and its diversity was carried out on the forest vegetation of the district of Saïda. The floristic diversity of our study area revealed the existence of 397 taxa belonging to 64 families and 271 genera. The most important families are Asteraceae (42 genera), Fabaceae (25 genera), Brassicaceae (22 genera) and Poaceae (22 genera). The category of rare taxa represents 13% of the studied flora (52 taxa). In our study area, we have counted 35 endemic regional species of which 19 species are endemic Algerian-Moroccan, and 3 species are strictly endemic to Algeria. Among the taxa analysed, 02 are included in the IUCN Red List, and 12 are on the Algerian list of protected non-cultivated plant species.

Juniperus oxycedrus L. and Pistacia lentiscus L. are two taxa with a rigid or rigid enough structure caused by a solid pericarp resulting in a strong inhibition of the germination. The objective of this work was to test the effectiveness of certain pre-germinative treatments on the germination rate of the Juniperus oxycedrus and Pistacia lentiscus seeds with the aim of restoring perturbed ecosystems. In this context 180 seeds from each of the 2 examined species were tested in the laboratory (the number of repetitions is 5, to reach the degree of freedom 'ddl'). The seeds were divided into 4 groups of 20 seeds of each species and were treated as follows: 1) Immersion in the concentrated (95%) sulphuric acid (H₂SO₄) for 10, 30 and 60 minutes; 2) Mechanical scarification with a scalpel; 3) Soaking in hot water (at 100°C) for 30 seconds, 60 seconds and 2 minutes; 4) Cold stratification at 5°C for 24 hours. There is also a control group of 20 seeds representing each of the two species, which remained neutral. In the case of the Juniperus oxycedrus seeds the results showed that the germination rate improves after the mechanical scarification with a scalpel (92%), followed by the cold stratification with water (86%) and a treatment with a concentrated sulphuric acid for 60 minutes (82%). The seeds were treated with H₂SO₄ for 10 and 30 minutes, respectively, soaked in hot water; the control lot did not germinate. The germination rate for the Pistacia lentiscus seeds is 88% after the mechanical scarification and 84% after the cold water stratification. On the other hand, the treatment with H₂SO₄ or after soaking in hot water does not allow for the germination of these seeds. The same result is observed on the control group (0% for 30 days).

Modeling potential habitat for plant species is an appropriate approach to maintain biodiversity, developing proper reforestation campaigns, and rehabilitating ecosystems. In this study, we investigated the potential distributions of four forest species, namely, Quercus faginea Lam.; Q. ilex L.; Tetraclinis articulata (Vahl) Mast.; and Pistacia atlantica Desf. In the north-western Algeria at Saïda region. The MAXENT method was used to model the habitats of these species using topographic data as predictive variables at a resolution of 100 m. Moreover, the model evaluation process was achieved using the area under the operating characteristic curve of the receiver (AUC) and Jackknife test. The generated models were found to be accurate. AUC results are ranging between 0.98 and 0.91 for the training set and 0.87 and 0.97 for the testing set. The results of the distribution probability of this study provide a useful tool for the local decision-makers of reforestation campaigns.

Albardine ( Lygeum spartum L.) is one of the major native grass species of the semi-arid and arid regions of the Mediterranean basin. In Algeria, it is much more widespread on the high plateaus of southern Oranais. This species occupies an important place in the steppe region because it has many ecological, economic, and fodder interests. The present work aims to study the tolerance of L. spartum seeds to water and salt stress, two abiotic factors that affect the physiology of the plant during the germinal stage. The methodology adopted consists of using increasing concentrations under a controlled temperature (15°C) for 21 days of germination. The germination responses of the seeds to different degrees of salt stress induced by NaCl (2, 4, 6, 8, 10 g/l) and water stress induced by polyethylene glycol (PEG;−2, -4, -6, -8, −10 bar), showed that the salt and water stresses retarded the germination rate of L. spartum L. seeds and also decreased their percentage during the time of the experiment. However, seeds soaked in distilled water (control) recorded a maximum germination rate of 80%. The results of this study show that L. spartum seeds are moderately salt and drought tolerant with a depressive effect on germination rate at a salt concentration of 10g/l and an osmotic pressure of −10 bar.

The identification of ecologically homogeneous zones is crucial and represents one of the key steps in ecosystem planning, management, and restoration. It allows targeted ecological restoration efforts based on the interactions between environmental factors. The approach of this study is pixel-based to identify ecologically homogeneous zones within the green oak forest in Elhassana area, western Algeria. This approach uses remote sensing indicators such as the normalized difference vegetation index (NDVI), leaf area index (LAI), soil-adjusted vegetation index (SAVI), normalized difference moisture index (NDMI), elevation, slope, aspect, relative slope position (RSP), and topographic wetness index (TWI), derived from Landsat 8 and Terra/ASTER satellite imagery to identify homogeneous zones. We use principal component analysis (PCA) to reduce the dimensionality of the data and identify the most important variables. This analysis helps to better understand the structure of the data and determine which variables have the most influence on the unsupervised classification using the iso cluster algorithm. The results of this study allowed us to visualize and map four types of homogeneous zones and characterize their ecological attributes. This information is invaluable for forest planners, enabling sustainable environmental management and the development of an ecological restoration plan for the green oak forest.