This site occupies the north-western and central part of Mahé (c.20% of the whole island) and contains Morne Seychellois National Park (3,090 ha), which includes the highest mountain of Seychelles (914 m). Its steep slopes are covered with dense secondary forests and shrub woodland, interrupted by impressive cliffs and granite boulders (glacis). This IBA also includes the mountainous area to the south-east, between the former Satellite Tracking Station (New Savy), Cascade, Montagne Planeau, Grand Bois, Castor, Varigault and Mont Sébert. This area lies outside the national park, but a project exists to partially protect it. The adjacent areas of La Misère and Cascade, also included, are mainly occupied by man-modified habitats, such as residential areas, orchards, small-scale agriculture and cattle farms, tea plantations, roads, powerlines and other infrastructure. Forests of low and intermediate altitudes are dominated by exotic, invasive trees (mainly Cinnamomum verum, Paraserianthes falcataria and Alstonia macrophylla), shrubs (the invasive exotic Chrysobalanus icaco), and huge granite boulders but, above 600 m in the Morne Seychellois National Park, stands of primary moist forest with few exotics still remain. Endemic species include Medusagyne oppositifolia and Vateriopsis sechellarum (both very rare), Dillenia ferruginea and Northea hornei (more common), Phoenicophorium borsigianum and Nephrosperma vanhoutteanum, Erythroxylum sechellarum, Nepenthes pervillei and Secamone schimperianus. During the nineteenth and the first half of the twentieth centuries extensive exploitation of timber and cinnamon production took place. Present human activities (forestry, nature conservation/research, tourism and a little tea cultivation), are limited to less than 10 % of the total area of the IBA.
See Box and Table 2 for key species. This site contains virtually the world population of Otus insularis (90–180 pairs). The La Misère, Haut Barbarons, and Cascade areas are the only three known significant breeding sites on Mahé for Zosterops modestus (c.12 pairs plus helpers, with about 10–15 birds at each site). These hold about 10% of the world population for this species. The IBA also holds 60–120 pairs of Falco araea (about 25% of the world population) and Collocalia elaphra, of which there are probably several hundreds of pairs, nesting in as yet undiscovered colonies. One cave near Le Niol, apparently occupied in the past, is now deserted. Due to its large size, the site is also of great importance for Alectroenas pulcherrima (>350 pairs), Hypsipetes crassirostris (1,700–2,400 pairs) and Nectarinia dussumieri (1,500–2,300 pairs). Other species of interest include Streptopelia picturata picturata, Phaethon lepturus (at least 200 pairs) and Gygis alba. Butorides striatus and Gallinula chloropus occur in ponds at low altitude.
Non-bird biodiversity: Four species of frogs and six species of caecilians endemic to Seychelles occur. The IBA is the main stronghold for the rare endemic tiger chameleon Chamaeleo tigris and contains important populations of the endemic snakes Lamprophis geometricus and Lycognathophis seychellensis. Several endemic skinks and geckos are also present. The site also hosts small numbers of the bat Coleura seychellensis seychellensis (CR) and large numbers of the bat Pteropus seychellensis.
BirdLife International (2021) Important Bird Areas factsheet: Mahé highlands and surrounding areas. Downloaded from http://www.birdlife.org on 07/03/2021.