Mount Nállume

A(i)Site contains one or more globally threatened species

Mount Nállume qualifies as an Important Plant Area under criteria A and C. Under criterion A(i) the site supports populations of three globally threatened species: Euphorbia grandicornis (EN), Streptocarpus myoporoides (EN) and Vepris macedoi (EN). The site nearly qualifies under criterion C(iii), having significant areas of Medium Altitude Moist Forest, a restricted and nationally threatened habitat, but it is not considered to be among the five best sites nationally for that habitat.

Mount Nállume, also known as Serra Chinga, is a granite inselberg in Ribáuè and Murrupula Districts of Nampula Province, ca. 25 km south-east of the town of Ribáuè. It forms part of a band of inselbergs in northern Mozambique running north-east from Mount Namuli and including Mount Inago, Serra Merripa [MOZTIPA048] and the Ribáuè Massif [MOZTIPA001]. The IPA includes a series of irregular granite rock outcrops, partially covered by forest and reaching an elevation of ca. 1,420 m. The site covers an area of approximately 115 km2 and is not formally protected at present.

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Significant areas of both median altitude moist forest and granite inselberg habitat can be found at Mount Nállume. These habitats are restricted and threatened in Mozambique. In addition, three threatened endemic plants occur here, of which two, the herb Streptocarpus myoporoides and tree Vepris macedoi are only found on Mount Nállume and the nearby Ribáue massif (Osborne et al. 2019, Darbyshire & Rokni 2019). The third, a spiny succulent Euphorbia grandicornis, is known from only Mount Nállume and two sites to the east of Nampula city (Osborne et al. 2019). All three plants are assessed as Endangered on the IUCN Red List of Threatened Species (IUCN 2020). Other notable species occurring at Mount Nállume include two further endemics, the cycad Encephalartos turneri and the suffrutescent herb Bothriocline moramballae, as well as the forest tree Maranthes goetzeniana, which is widespread in the region but sparsely distributed and assessed as Near Threatened (Timberlake et al. 2018). The site is not well-studied botanically and other notable plant species are likely to occur here.

The landscape at Mount Nállume consists predominantly of granite inselberg slopes ranging from curved granite domes to steep cliffs. These granite slopes support an interesting and diverse flora of herbs and shrubs, typically including many succulents. Crevices and gullies in the rock provide numerous microhabitats supporting plant diversity. Moist forest patches cover a significant area of the inselberg, the canopy mostly 15-20 m tall though reaching over 40 m in places (Platts pers. comm. 2020). However, a large part of the forest has been cleared recently through logging and for subsistence agriculture, particularly at the base of the granite slopes. On top of the inselbergs water from the moist forest forms swamps and drains into frequent streams. At the base of the granite slopes meandering stream are conspicuous on satellite imagery (Google Earth 2020) supporting narrow bands of dark green riparian forest within a mosaic of agricultural land, secondary scrub or grassland and fragments of woodland.

The forest at Mount Nállume is under increasing threat due to logging and forest clearance for subsistence agriculture. Biologists who visited the site in 2019 estimate forest loss of more than 30% over the past 10 years and suggest that all the forest could be lost within 15 years at the current rates of deforestation (Njagi 2019). Fire presents another threat to the forest, both unintentional spread of fires used by local people to clear agricultural fields surrounding the inselbergs and fires set intentionally by hunters to drive animals into traps in the forest (Njagi 2019). These fires are damaging the forest edge but are a secondary threat when compared to the current rate of forest clearance for subsistence agriculture (Platts pers. comm. 2019). The site falls under the jurisdiction of the local district authorities for three separate districts, Ribáue, Mecuburi and Murrupula (Njagi 2019) but it is not formally protected by the Mozambique Government.

Mount Nállume has a high plant diversity value providing moist forest and granite inselberg habitats for flora and fauna within a predominantly agricultural plain. Timber and medicinal plants from the forest are used by local people, some of whom also depend on wildlife hunting for food (Njagi 2019). The inselberg forests have cultural and spiritual value to the local community, being considered sacred and used as sites for performing traditional rituals (Njagi 2019). The forested inselbergs provide a watershed for the local area and the vegetation contributes to carbon sequestration and storage.

Jo Osborne, Royal Botanic Gardens, Kew

Iain Darbyshire, Royal Botanic Gardens, Kew