Status and social structure of the critically endangered dama gazelle (Nanger dama) in the Aïr & Ténéré National Nature Reserve, Niger

The dama gazelle ( Nanger dama (Pallas, 1766)) is one of the largest of all gazelles, and also one of the world’s most endangered antelopes listed as Critically Endangered on the IUCN Red List. Today, only a few small and highly scattered populations persist, mainly in Niger and Chad. This study provides recent insights into the population status, structure, and phenotypic diversity of dama gazelles in the Aïr & Ténéré National Nature Reserve (ATNNR), focusing on the Mount Takolokouzet, and based on 15 field missions conducted between 2017 and 2023. Distribution and relative abundance were assessed using direct observations, indirect signs, and camera traps. The Kilometric Index of Abundance (KIA) averaged 0.058 for direct observations and 0.16 for indirect observations, showing a positive trend over time, particularly for indirect evidence. Camera trap data revealed an overall capture rate (CTR) of 1.59 independent events per 100 trap-days, with increased detection during recent targeted efforts. Demographic analysis was based on 39 direct sightings (84 individuals) and 200 independent camera trap events (244 individuals). Solitary individuals were primarily adults, representing 83 % of camera trap records and less than half of direct sightings. Group sizes were from 2 to 7 (direct) and 2–4 (camera traps), with an overall mean of 2.95 individuals. Adults were dominant in both datasets, while juveniles and subadults comprised less than 20 % of individuals. Calving was observed in two distinct seasonal periods. Phenotypic diversity in the dama gazelle population at ATNNR was marked by traits associated with different coat patterns. The N. d. dama phenotype was the most common (73 %), with smaller proportions exhibiting distinct variations (18 % and 9 %). This suggests a phenotypically mixed population, but caution is needed as subspecies differentiation remains debated. The variation may represent a spectrum rather than distinct subspecies. Our results highlight the importance and fragility of a small, little-known population of dama gazelle on Mount Takolokouzet. The consistently low proportion of young individuals highlights concerns about recruitment. Our findings justify urgent conservation measures focused on securing refuges, reducing disturbance, sustaining monitoring, and protecting breeding females during calving peaks, while ecological drivers will be examined in future work.