Udzungwa red colobus  (Piliocolobus gordonorum)

The Udzungwa red colobus has a limited range that continues to shrink and become increasingly fragmented (2). The species has suffered from habitat destruction and degradation due to construction of a railway within its range, combined with extensive logging, agricultural expansion, collection of firewood and charcoal production (5) (6). Habitat degradation remains a serious concern due to the impact on social groups (9). Studies have indicated that reproductive success, group size and group density are significantly reduced in small and degraded forests (5). The small forest remnants in the Kilomero Valley that lie outside of protected areas, or lack the protection they were promised, are particularly vulnerable (5). Reduced social group size increases vulnerability to predators (9) and poachers, with hunting for Udzungwa red colobus meat, considered a delicacy, posing another serious threat to the species (2).

The Udzungwa red colobus is found in four protected areas in Tanzania: Magombero Forest Reserve, Selous Game Reserve, Udzungwa Mountains National Park (2) and New Dabaga/Ulangambi Forest Reserve (NDUFR) (10). Udzungwa Mountains National Park, which holds the largest population of these monkeys, has no roads and all access is by foot, limiting potential disturbance (8). Elsewhere, however, the species occurs either on public land or in forest reserves that are not effectively protected (5). Since studies have shown that reduced habitat quality adversely affects group density, size, composition and recruitment, closed-canopy forest is considered to be crucial for the long-term survival of this endangered colobus monkey (6). Indeed, the Udzungwa Mountains contain a rich array of biodiversity, including at least ten primate species, and as such, constitute an area of global importance for biodiversity conservation (11). Thus, protecting the forests of these mountains must be a priority not only for the Udzungwa red colobus, but for all the fauna and flora that share this diminishing habitat.