The influence of stand age on wildlife habitat use in exotic Teak tree Tectona grandis plantations

Abstract

Tropical dry woodlands provide important natural resources for both humans and wildlife, but woodlands situated outside protected areas are vulnerable to over-exploitation. In the Kilombero Valley, Tanzania, miombo woodland is converted into teak plantations and small, private farms, but the impact of this habitat change on wildlife populations is poorly understood. We assessed the frequency of habitat use of large mammals in teak plantations of different age during the wet season. Vegetation structure varied significantly with age; older plantations had larger trees, a more extensive shrub layer and a well-developed leaf litter. Younger plantations had smaller trees and larger areas of short vegetation and bare ground. Track surveys revealed that older plantations were predominantly used by bush pig Potamochoerus larvatus, bushbuck Tragelaphus scriptus and duiker (Cephalophus harveyii, C. natalensis or Sylvicarpa grimmia), whilst the younger plantations were used by open-habitat specialists such as warthog Phacochoerus africanus and waterbuck Kobus ellipsiprymnus. Proximity to the flood plain was also found to be important and plantations nearest this area contained significantly more tracks of large grazers and bulk feeders, reflecting use by zebra Equus burchelli, buffalo Syncerus caffer and waterbuck. Areas of miombo woodland that have been converted into teak plantations provide suitable habitat for wildlife in the Kilombero Valley, but their conservation value diminishes with time. Future management should therefore aim to maintain the patchwork of miombo woodland and teak plantations in order to provide suitable habitat for a range of wildlife. Where possible, teak plantations should not be situated close to the boundary of the miombo woodland and flood plain because this habitat is an important wet season refuge for wildlife during the wet season.