The site is centred on an area of near-vertical cliffs, where the upper reaches of the Senqu (Orange) river have incised deeply into the basalt layers. The surrounding highlands support a traditional pastoral economy with a low-density population. Approximately 35% of the surrounding area (within a 25 km radius) is cultivated, the remainder being open pasture. The vegetation is primarily montane grassland, but thick bush and scrub flank the lower gorge walls. High-altitude shrubs form a heath of Erica, Chrysocoma and Helichrysum. The summits are generally rocky with bare, shallow soil patches and extensive bare rock at higher altitudes.
See Box and Tables 2 and 3 for key species. The cliffs hold 84 breeding pairs (226 birds) of Gyps coprotheres, in two ‘stable nucleus’ colonies and four satellite colonies. Several undiscovered colonies are suspected to exist within the IBA. The site also incorporates the foraging areas around the colonies, as well as a roost site. Undoubtedly some exchange occurs between the colonies. The area around Mokhotlong, which means ‘the place of the Bald Ibis’, is important for breeding Geronticus calvus. Several groups, comprising up to 200 birds, have been seen in the vicinity. The steep inaccessible cliffs of the Senqu, Moremoholo and Mokhotlong rivers are undoubtedly one of this species’s strongholds in Lesotho. The rare but widespread Gypaetus barbatus meridionalis also forages widely across this area. Other cliff-nesting species include Buteo rufofuscus, Falco biarmicus and Ciconia nigra (3–5 pairs); the latter is particularly common along the Senqu river valley. The high-altitude, rocky, boulder-strewn slopes and outcrops (above 2,000 m) support Chaetops aurantius, and the surrounding grassy slopes and plateau hold Anthus hoeschi, which breeds in large numbers during the austral summer (especially above 3,000 m). Serinus symonsi occurs commonly above 1,500 m, and has become commensal with humans, occupying and foraging in villages and among fallow and harvested crop fields. Anthus crenatus, Monticola explorator and Geocolaptes olivaceus occur commonly in the vicinity of rocky outcrops. Cercomela sinuata hypernephela, Sylvia layardi barnesi and Circus maurus are uncommon. The small, isolated, endemic subspecies Parus afer arens also occurs.
Non-bird biodiversity: The alpine floral communities found in the Maloti/Drakensberg mountains are unique in southern Africa, holding a remarkable number of endemic species. A recent botanical survey of three valleys in the Maloti yielded many species that could not be identified and some may be new to science. Extremely rare and localized butterflies occur in the Senqu Valley region, including Torynesis pringlei (endemic), Metisella syrinx and Lepidochrysops loewensteini (VU). The high-altitude streams and seepages hold the Drakensberg-endemic frogs Strongylopus hymenopus and Amieta vertebralis. Near-threatened endemics such as the lizards Pseudocordylus langi (LR/nt) and P. spinosus (LR/nt) and the threatened mouse Mystromys albicaudatus (VU) are also known from this region. The extremely poorly known endemic and threatened small mammal Chlorotalpa sclateri (VU) may occur here.
BirdLife International (2020) Important Bird Areas factsheet: Upper Senqu River. Downloaded from http://www.birdlife.org on 04/07/2020.