The Mount Nimba Strict Nature Reserve is renowned for its exceptional biodiversity and unique species that thrive within its diverse ecosystems. Here are some key aspects of its biodiversity and uniqueness:

Endemic Species: Mount Nimba is home to numerous endemic species, meaning they are found only in this specific region. These vascular plant, invertebrate, and vertebrate species like the Western Nimba toad (Nimbaphrynoides occidentalis), Lamotte's roundleaf bat (Hipposideros lamottei), among others. The reserve's isolation and distinct ecological conditions have allowed the evolution of these specialized species.

Primate Diversity: Mount Nimba is known for its rich primate diversity, with several species of monkeys inhabiting the area. This includes the critically endangered Western chimpanzee (Pan troglodytes verus), which is the most threatened subspecies of chimpanzee. Other primates found in the reserve include the Western red colobus (Piliocolobus badius), the Diana monkey (Cercopithecus diana), and the sooty mangabey (Cercocebus atys).

Avian Species: The reserve is a haven for birdwatchers due to its impressive bird diversity. It is home to over 393 bird species, including endemic and threatened species. The white-necked rockfowl (Picathartes gymnocephalus) is an iconic bird species found in the area and is known for its unique appearance and nesting habits. Other notable bird species include the Hooded vulture (Necrosyrtes monachus), African pied hornbill (Lophoceros fasciatus), Rufous fishing owl (Scotopelia ussheri), woodland kingfisher (Halcyon senegalensis), white-troated bee-eater (Merops albicollis), and the Nimba flycatcher (Melaenornis annamarulae).

Mammal Diversity: Mount Nimba supports a wide range of mammal species. Alongside the Western chimpanzee, it provides habitat for species like African elephants (Loxodonta africana), African buffaloes (Syncerus caffer), Western bongos (Tragelaphus eurycerus), sitatungas (Tragelaphus spekii), leopards (Panthera pardus), pygmy hippos (Choeropsis liberiensis), and zebra duikers (Cephalophus zebra). These mammals contribute to the overall ecological balance and richness of the reserve.

Plant Diversity: The flora of Mount Nimba is highly diverse, with approximately 2,000 plant species identified of which 16 are considered to be strict endemics. The reserve is characterized four major vegetation types: montane grasslands with Loudetia kagerensis on the highest elevations; lush montane forests between 1400 and 700 meters dominated by Parinari excelsa; lowland forests below 800-600 meters, which harbor highest tree diversity with various species like Triplochiton scleroxylon, Chlorophora regia, Morus mesozygia, Terminalia ivorensis, Lophira procera, Tarrietia utilis, Piptadeniastrum africanum, Parkia bicolor, Mapania spp. among the dominants; and forest-savanna mosaics in the surrounding lowlands. The region is also known for its orchid diversity, with numerous colorful and unique orchid species dotting the landscape.

Geological Significance: Mount Nimba's geological features add to its uniqueness. The mountains are rich in iron ore deposits, which have attracted mining activities in the past. The combination of high altitude, dense forests, and rich minerals makes Mount Nimba an extraordinary blend of geological and biological diversity. The combination of endemic plant species, diverse primate and bird populations, and unique geological features make the Mount Nimba Strict Nature Reserve an exceptional and irreplaceable ecosystem. Preserving its biodiversity and protecting its habitats are crucial for maintaining the reserve's ecological integrity and the survival of its rare and remarkable species.

To summarize the reserve’s unique biodiversity features, 132 mammal species, 393 avian species, 69 reptile species, 62 amphibian species, and 28 freshwater species recorded so far.