Scarcity and endemism are considered the most important concepts of a region’s biodiversity and conservation. Nevertheless, our understanding of the models of scarcity and endemism is limited to high biodiversity regions as, for example, the wilaya of Souk Ahras, northeastern Algeria. In this study, we have compiled a list of all heritage species, their taxonomic composition, and geographic distribution. A total of 119 species was documented, and their distribution was as analyzed in the biological environments of two distinct phytogeographic sectors — C1 and H2. The rate of scarcity and endemism increased alongside the organic matter richness and, as a result, the forest and pre-forest area supported an over-representation of these species. The preservation of this biodiversity, exceptional and threatened, urgently requires appropriate scientific studies and environmental protection as short term measures.