The research team, led by Badreldin A. A. Mohamed of the Wildlife Research Center in Khartoum and Salwa Mansour Abdelhameed of the Sudanese National Commission for UNESCO, carried out systematic field surveys during the wet seasons of June and July and the dry seasons of January and February in 2021 and 2022. Their toolkit combined standardized line transects along locally known footpaths running from the foothills to the summit, camera traps deployed for roughly 720 hours across representative sites in the Fawas habitat, and nocturnal spotlight surveys along vehicle-accessible routes. In total, 64 transects of 100 by 10 meters were walked on foot, covering a cumulative sampled area of 64,000 square meters. Records included direct sightings as well as indirect evidence such as tracks, feces, burrows, feathers, and bones, with strict measures to avoid double counting.

The tally that emerged is remarkable for a semi-arid reserve facing intensifying human pressure. The 191 species comprised 42 mammals, 112 birds, 19 reptiles, 4 amphibians, 12 insects, and 2 mollusks, representing six major taxonomic groups and an array of ecological niches. Birds dominated the assemblage, accounting for 60.4 percent of all observations, followed by mammals at 18.2 percent and insects at 15.6 percent. Crucially, the numbers were not static. Overall abundance in the wet seasons reached 2,510 individuals, roughly double the 1,256 records gathered during the dry seasons, a difference that held consistently across both study years.

Statistical analyses confirmed what the raw counts suggested. Because abundance data deviated significantly from normality, the researchers applied the Kruskal–Wallis H test followed by Dunn’s post hoc comparisons with Bonferroni adjustment. Seasonal differences were highly significant (H = 83.63, df = 3, P < 0.001), with each wet season differing from each dry season, while the two dry years and the two wet years were statistically indistinguishable from one another. This pattern implies a stable, predictable seasonal rhythm rather than random year-to-year fluctuation. Diversity indices told the same story: bird Shannon–Wiener diversity ranged from 3.61 to 4.19 and peaked during Wet 2021, accompanied by very low Simpson’s dominance and high Pielou’s evenness, while mammals reached their highest wet-season diversity with H′ values between 3.24 and 3.28.

Species richness shifted just as dramatically. Bird species climbed from 55 to 59 during the dry seasons of 2021 and 2022 to 90 and 89 during the corresponding wet seasons, and amphibians showed perhaps the sharpest response of any group, with 71 individuals recorded in the wet seasons against only 9 in the dry ones. The mechanism is well understood in savanna ecology: rainfall triggers pulses of primary productivity, expands temporary water sources, and cascades through food webs as insects, seeds, and fruits become abundant. For amphibians, whose breeding depends on ephemeral pools, the wet season is essentially the only viable window. Birds, including migratory and seasonal visitors that made up 48 percent of recorded species, ride the same resource wave. Mammals, more buffered by mobility and physiology, showed a smaller but still clear seasonal rise.

Perhaps the most ecologically revealing finding concerns the reserve’s internal geography. The study distinguished six habitat types: four natural ones—Higher Elevation, Fawas (the enclosed plains wedged between rocky hills), Upland Valleys and Streams, and Lower Slopes—and two human-modified ones, Farm Areas and Residential Areas. The Fawas habitat supported the highest overall abundance with 941 individuals and the greatest species richness across most taxonomic groups, while the Higher Elevation habitat recorded the fewest animals, only 214. Kruskal–Wallis testing confirmed significant differences among habitats (χ² = 95.386, df = 5, P < 0.001), with Higher Elevation differing significantly from every other habitat and the Fawas differing from Upland Valleys and Streams, Lower Slopes, and Residential Area. Notably, Farm Areas came second in abundance at 851 individuals, showing that even agricultural mosaic can sustain substantial wildlife when it offers crops, residues, and insect prey.

Behind the aggregate numbers lie individual species of considerable conservation weight. The mammal inventory included the olive baboon as the most abundant species at 95 individuals, the greater kudu recorded consistently across seasons and habitats, and rarely seen residents such as the aardvark, Egyptian mongoose, and Egyptian tomb bat, each represented by a single individual. Three mammals—the straw-coloured fruit bat, the patas monkey, and the striped hyaena—were classified as Near Threatened by the IUCN Red List. Among birds, the reserve hosts six globally threatened or Near Threatened species, including the Critically Endangered white-backed vulture (Gyps africanus) and hooded vulture (Neophron monachus), alongside Endangered steppe and tawny eagles, the lappet-faced vulture, and the pallid harrier. The reptile fauna included the Endangered African spurred tortoise (Centrochelys sulcata) and two Near Threatened python species, underscoring the reserve’s value far beyond its national borders.

To ensure their inventory was not an artifact of under-sampling, the team employed individual-based rarefaction and extrapolation using the iNEXT framework, and the species accumulation curves approached an asymptote for all major taxonomic groups, suggesting the surveys captured most detectable species within the surveyed habitats. The authors are candid about limitations: abundance estimates did not correct for detection probability, remote areas were inaccessible during the rains, and invertebrates were sampled through opportunistic hand collection that likely understates true diversity. Even so, the dataset represents a leap forward. Previous work at Jebel Al-Dair had focused on management planning, vegetation, or localized observations of birds and snakes, but never before had a single study quantified wildlife diversity across multiple taxonomic groups with standardized surveys and inferential statistics.

The conservation implications are pointed. Sudan’s protected area network remains under-resourced and under-representative of many ecosystems, and Jebel Al-Dair faces mounting threats from agricultural expansion, overgrazing, fuelwood harvesting, settlement growth, and illegal hunting. The study’s recommendations are correspondingly practical: prioritize protection of the Fawas and Upland Valleys and Streams, safeguard dry-season refuges and permanent water sources when animals concentrate into limited areas, restore degraded habitats, strengthen community-based conservation, and embed long-term standardized monitoring into an adaptive management plan. Because wet-season wildlife disperses broadly while dry-season animals cluster near water and shelter, patrol and monitoring schedules should track these temporal shifts rather than assume static distributions.

Beyond its local significance, the study positions Jebel Al-Dair as a reference site for the wider Sahel, where dryland biodiversity is declining under climate stress and land-use change and where ecological data are chronically scarce. The occurrence of both resident and migratory birds confirms the reserve’s role along the Afro-Palearctic flyway, and its inselberg-like mountain habitats mirror patterns seen at rocky outcrops across Africa where topographic complexity generates ecological niches that persist despite harsh conditions. In documenting 191 species in a single reserve, the researchers have supplied not just a species list but a baseline against which future change—whether from climate, development, or conservation action—can be measured, and a demonstration that even a semi-arid mountain in western Sudan can rank among the region’s most important biodiversity refuges.

Subject of Research: Seasonal and habitat-based patterns of wildlife diversity in a Sudanese semi-arid biosphere reserve

Article Title: Seasonal and habitat based patterns of wildlife diversity in Jebel Al Dair Biosphere Reserve, Sudan

Article References: Mohamed, B. A. A., & Abdelhameed, S. M. (2026). Seasonal and habitat based patterns of wildlife diversity in Jebel Al Dair Biosphere Reserve, Sudan. Discover Animals, 3(1), Article 92. https://doi.org/10.1007/s44338-026-00251-6

Image Credits: AI Generated

DOI: 10.1007/s44338-026-00251-6

Keywords: wildlife diversity, Jebel Al Dair Biosphere Reserve, Sudan, biodiversity, seasonal variation, habitat heterogeneity, conservation biology, semi-arid ecosystem, species richness, IUCN Red List, camera trapping, protected areas