are not uncommon. Bardaï, located above sea level, experiences average temperatures ranging between in January, between in April, and between in August. The combination of high temperatures and low humidity results in potentially high evaporation rates, ranging from in January to in May, parching many enneris before they can exit the mountain range. Flora and fauna Like an island surrounded by ocean, the ecology of the Tibesti Mountains is distinguishable from that of the surrounding desert. As such, the mountains lie within their own biome, the Tibesti-Jebel Uweinat montane xeric woodlands ecoregion, along with the Jebel Uweinat, a disjunct mountain range that also rises from the Sahara to the east. Much of the ecoregion remains unexplored due to its remoteness and persistent political instability, yet it is known to contain a number of endemic and endangered species. Indeed, the isolation of the region is a benefit to its flora and fauna, serving as a sort of refuge, allowing plants to grow untrammeled and animals to roam unmolested. Nevertheless, hunting is unregulated in the region, and vegetation has suffered from overgrazing in the past. Flora The flora in the Tibesti is Saharomontane, mixing Mediterranean, Sahara, Sahel and Afromontane vegetation. Biodiversity and endemism levels are higher in the Tibesti than in the Aïr Mountains or the Ennedi Plateau, although the vegetation's coverage is highly dependent on rainfall. Oases lie along the courses of the enneris, such as Enneri Yebige. These oases, which are more numerous to the north and west of the range, are scattered with acacia, figs, palms and tamarisks. Most gueltas are lined with macrophytes—including smooth flatsedge (Cyperus laevigatus) and branched horsetail (Equisetum ramosissimum)—and bryophytes—including Oxyrrhynchium speciosum and species of Bryum. Egyptian acacia (Vachellia nilotica syn. Acacia nilotica) grows near these water basins. Saharan myrtle (Myrtus nivellei) and oleander (Nerium oleander) grow between elevations of in the western part of the range, while Nile tamarisk (Tamarix nilotica) grows at similar elevations in its northern part. Downstream, where the current of the enneris is slower and the riverbed is deeper, there are dense thickets of Athel tamarisk (Tamarix aphylla syn. Tamarix articulata) and arak (Salvadora persica). Around the edge of the Tibesti, where the canyons exit the range, are doum palms (Hyphaene thebaica). The banks of Mare de Zoui are home to dense stands of reeds (Phragmites australis and Typha capensis), along with sedges (Scirpoides holoschoenus), sea rush (Juncus maritimus), toad