Exploring and preserving an ecological treasure.

The South Pare Mountains, part of the Eastern Arc - Tanzania

The South Pare Mountains, part of the Eastern Arc - Tanzania

We actively work with local communities, regional and national agencies, and other organizations to explore, restore and conserve the biodiversity and environments of the Eastern Arc Mountains by reducing deforestation and habitat distruction. The goals of the Eastern Arc Conservation Program include:

  • Identification, documentation, and assessment of endemic plant and animal species.
  • Identification of threats to specific species and the environment as a whole, and specification of fields of action for regional environmental policy.
  • Replanting of native species in degraded areas.
  • Public awareness programs designed to educate local residents about the Eastern Arc environment and its importance to the region.


The Eastern Arc Mountains, located in southern Kenya and eastern Tanzania, are renowned in Africa for their high concentrations of endemic species of animals and plants. The chain comprises thirteen separate mountain blocks and supports approximately 3,300 km2 of sub-montane, montane, and upper montane forest. At least 96 vertebrate species (10 mammal, 19 bird, 29 reptile, and 38 amphibian) are endemic, among which are four endemic (or nearly endemic) species of primate: the Sanje Mangabey, the Iringa Red Colobus, the Mountain Galago, and the newly discovered Kipumji monkey. A further 71 vertebrate species are near-endemic. At least 800 vascular plant species are endemic, almost 10% of these being trees. These endemics include the majority of the species of African violet, or Saintpaulia, a well-known flowering plant in Western households. Many hundreds of invertebrates are also likely to be endemic, with data for butterflies, millipedes, and dragonflies indicating potential trends of importance.

Seventy-one of the endemic or near-endemic vertebrates are threatened by extinction (8 critical, 27 endangered, 36 vulnerable), with an additional seven wide-ranging threatened species. Hundreds of plant species are also threatened.


The current extent of forested area in the Eastern Arc is less than 30% of the estimated original. Most of the remaining forest is found within nearly 150 government forest reserves, with 106 of these managed nationally for water catchment, biodiversity, and soil conservation, and where forest exploitation is not allowed. Outside of these areas most forest has been cleared, except in small village burial/sacred sites, a few village forest reserves, and inaccessible areas.

In most Eastern Arc Mountains the local populations have not developed farms beyond the reserve boundaries, but they have used forest resources within the boundaries for fuel and building materials, and some forests are heavily degraded. Fire is also a problem, as it enters and destroys forests during the dry seasons.

The future biodiversity of the Eastern Arc Mountains depends upon the management policies and capacity of the Tanzania Forest and Beekeeping Division, the Tanzania National Parks Authority, and the Kenya Forest Department. Supporting these agencies is an essential long-term conservation investment.

Villagers carry wood harvested from a forest preserve to their homes to make charcoal for cooking fuel - Tanzania

Villagers carry wood harvested from a forest preserve to their homes to make charcoal for cooking fuel - Tanzania