Mount Zembe

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

Mount Zembe qualifies as an important plant area under criterion A(i), supporting populations of three globally threatened plant species: Encephalartos munchii (CR), Aloe decurva (CR) and Coffea salvatrix (EN). The only known populations of Encephalartos munchii and Aloe decurva occur here.

Mount Zembe is a granite inselberg in Macate District of Manica Province, 22 km south-west of Chimoio. It reaches 1,200 m in elevation, rising from the surrounding plains at ca. 600 m elevation. The site is approximately 6 km long by 2 km wide and comprises a series of granite rocks running north-east to south-west. This site is of importance for its interesting xerophytic flora on the exposed rock outcrops, as well as for the pockets of moist forest in gullies.

Next Previous

Mount Zembe is significant as it is the only known site for two plant species, the cycad Encephalartos munchii and the rosette-forming, low-growing aloe, Aloe decurva. These two endemic plants are assessed as Critically Endangered on the IUCN Red List (Donaldson 2009; Osborne et al. 2019). Both are largely confined to the summit of Mount Zembe, the cycad growing in bushland by streams and amongst rocks and boulders, the aloe being found only on exposed steep rocky slopes. Other interesting succulent species of note include the Mozambican endemic shrub or small tree euphorbia, Euphorbia graniticola (LC), and the scarce near-endemic stapeliad, Huernia leachii (LC). The site also supports a population of the Endangered wild coffee species Coffea salvatrix, or “mukofi” (O'Sullivan & Davis 2017), which occurs in the small patches of moist forest. These forest patches also hold a population of the Mozambique near-endemic Sansevieria (= Dracaena) pedicellata (LC) in the ground layer. A more complete botanical inventory of this site may reveal further species of conservation concern.

Mount Zembe is a granite inselberg that provides a range of different habitats according to slope, aspect, soil depth and moisture availability. Rock crevices and shallow soils over granite rock form the dominant habitat, supporting a range of herbs, including the tussock-forming sedge Coleochloa setifera, geophytes such as Drimia intricata and Ledebouria spp., and succulents including Euphorbia spp. and Huernia leachii. Open grassland covers flatter areas where deeper soils have formed. Woody vegetation, including small pockets of moist forest, is found where sufficient moisture is available in deeper rock crevices and stream gullies. The species composition of the different habitats on Mount Zembe has not been fully documented to date, and this should be considered a priority as a baseline for future monitoring.

Mount Zembe is not currently protected and is not included within any other conservation prioritization schemes, except that it is listed as an Alliance for Zero Extinction site based on the presence of Encephalartos munchii (AZE 2018). An increase in fire frequency on Mount Zembe presents a serious threat to the vegetation, particularly damaging immature plants. There has been some quarrying of rock for construction materials at the foot of Mt Zembe, and whilst this is not considered to be a major threat at present, it may expand in the future and threaten this site (Osborne et al. 2019). There is also a potential threat of over-harvesting by plant collectors for private collections and for the horticultural trade, particularly in the case of the cycad Encephalartos munchii and the aloe Aloe decurva, both of which are striking plants with the added appeal of their rarity. Other attractive succulents such as Euphorbia graniticola and Huernia leachii may also be targeted.
A reintroduction programme for E. munchii was initiated in 2003 when 1,000 – 1,300 seedlings were established by the Plantas de Moçambique project as a conservation measure (Capela 2006). There has been no record of how the seedlings and population have progressed since this time. However, this is due to be surveyed in the near future as part of a project led by the University of Kent and supported by the Mohamed Bin Zayed Fund (D. Roberts, pers. comm.).

Mount Zembe has a high plant biodiversity value and provides an island of natural habitat for flora and fauna within an agricultural plain. A wild relative of coffee, Coffea salvatrix, occurs here and the site therefore contributes to maintenance of crop genetic diversity. The inselberg provides a watershed for the local area and the vegetation contributes to carbon sequestration and storage. In addition, Mount Zembe has spiritual significance and cultural value to local people.

Jo Osborne, Royal Botanic Gardens, Kew

Iain Darbyshire, Royal Botanic Gardens, Kew