Udzungwa-Selous

Region: Iringa , Morogoro
Type: D - Known animal movement routes between two protected areas.
Threat: Extreme - probably less than 1 year remaining or already closed.

Anecdotal evidence indicates that, until recent decades, there was regular and abundant movement of large mammals between the Udzungwa and Selous ecosystems across the Kilombero Valley.

High levels of human immigration and a spread of agriculture throughout the valley during the second half of the twentieth century, including a vast monocultural sugar plantation, have resulted in most animal routes becoming blocked off.

A 2006 study into the feasibility of maintaining ecological connectivity between the Udzungwa and Selous PAs found that two routes remain active for wildlife: the Nyanganje and Ruipa Corridors.

However, it is predicted that without conservation interventions, both of these corridors will also be blocked by the end of 2009.

Udzungwa-Selous Corridor - Trevor Jones & Nick McWilliam 2008
Udzungwa-Selous Corridor - Trevor Jones & Nick McWilliam 2008

Udzungwa-Selous Corridor - Trevor Jones & Nick McWilliam 2008

Map: Trevor Jones & Nick McWilliam 2008

Description

Udzungwa-Selous: Northern end of Ruipa corridorThe Nyanganje Corridor is situated at a narrow ‘bottleneck’ of the Kilombero Valley and represents the shortest distance for animals to cross between the Udzungwa and Selous ecosystems.

From the Nyanganje FR (69 km2, centred on 36 o47’E, 8 o00’S) to the Selous GR is a straight distance of approximately 13 km. Here the Valley is a mosaic of low density shambas, degraded grassland and semi-natural grassland, scrub, marsh and scattered small patches of woodland. The most important area for protection is the corridor area closest to the Nyanganje FR, and adjacent to the road and railway, where there is scattered cultivation and some human-wildlife conflict (though no permanent human settlements). This critical section of the Corridor is about 3 km long and 0.5-2.5 km wide.

The Ruipa Corridor is situated close to the Ruipa river to the southwest of Ifakara, in the southern Kilombero Valley.

It begins at the large Matundu forest (ca. 250 km2, centred on 36o21’E, 7 o 86’S, split between the Udzungwa Mountains NP and the Kilombero Nature Reserve), and heads southeast up to and across the Kilombero River (from where animals disperse to reach the Selous GR). This large mammal corridor (0.5 – 6 km wide, 20 km long; a total area of ~ 25 km2) crosses a mosaic of habitats, including riverine forest, woodland, scrub, degraded pasture and swamp.

Wildlife

ElephantNyanganje Corridor: Elephant (during January-March) and buffalo still use the corridor annually to migrate between protected areas, although according to questionnaire respondents their numbers have reduced significantly in recent years. Other animals reported from the corridor include bushbuck, bushpig, leopard, lion, puku and yellow baboon.

Buffalo.jpgRuipa Corridor: Elephant (during March-May) and buffalo still use the corridor annually to migrate between Protected Areas, although according to questionnaire respondents their numbers have reduced significantly in recent years. Other animals reported from the corridor include the aardvark, Angolan black-and-white colobus, bushbuck, crested porcupine , Harvey’s duiker, bushbuck, hippopotamus, leopard, lion, puku, spotted hyaena, waterbuck and the Udzungwa-endemic Udzungwa red colobus.

Threats

Nyanganje Corridor: Amongst local farmers there is little perception of conflict with wildlife, apparently because elephants and other mammals cross farms rapidly at night without causing much damage to crops. However very few animals are still using the corridor, probably because of increased human activity – despite the narrow corridor being one of the less densely cultivated areas of the Kilombero Valley. The most immediate threat to the Corridor is the likelihood of intensified cultivation and human settlement until animals are completely unable to pass.

Ruipa Corridor: This Corridor is under immediate threat, especially in the Namwai forest area, from: rapid destruction of habitat by cutting of timber (including commercially) and burning; pole cutting and charcoaling; new human settlements and conversion of woodland to agriculture; hunting; increased cattle herding. An additional very recent threat is the settlement of Wasukuma immigrants along the western bank of the Kilombero River, with associated large herds of cattle and planting of crops.

Reference

Vanishing Corridors (unpublished report)