ORYX VOL 32 NO 4 OCTOBER 1998 Translocation and introduction of the Zanzibar red colobus monkey: success and failure with an endangered island endemic Thomas T. Struhsaker and Kirstin S. Siex The Zanzibar red colobus Procolobus kirkii is one of Africa's most endangered primates, with only c. 1500-2000 individuals remaining in the wild. The authors made preliminary surveys of three areas where this monkey was translocated or introduced in the 1970s and 1980s. It appears that only one of these releases was successful. A total of 67 animals were caught and translocated or introduced (including four that died during the process). Thirteen to 20 years later, 62-70 red colobus were located at the three sites; i.e. there had been no net gain in colobus numbers as a result of the translocations and introduction. One attempt apparently failed because of insufficient habitat, and another perhaps because of insufficient numbers ofcolobus or an imbalance in the age and sex composition of animals released. The one successful translocation involved moving a fairly large number of monkeys (36) into a forest with a relatively high diversity of tree species. In light of these findings, the authors recommend that far more attention be given to protecting the monkeys and their habitat where they currently exist, rather than spend time and money on translocations that are as likely to fail as to succeed. Introduction and building poles. Road-kills by vehicles and hunting are also important, but somewhat less The Zanzibar red colobus monkey Procolobus serious, threats to the monkeys (Struhsaker kirkii is endemic to the island of Zanzibar (lo- and Siex, 1997). cally referred to as Unguja) and the very small Zanzibar red colobus are important not only island of Uzi, which is joined to Unguja by a because of their unique characteristics and en- narrow isthmus of tidal mangrove swamp. dangered status, but also because they are a This species is Endangered (IUCN, 1996), with major tourist attraction and economic asset to approximately 1500-2000 individuals remain- Zanzibar (Struhsaker and Siex, 1997). Tourism ing in the wild (Struhsaker and Siex, unpubl. in Zanzibar is rapidly becoming a major reports). None is in captivity and more than source of revenue for the islands. Tourism to half of the wild population lives outside pro- Jozani Forest Reserve, mainly to view the tected areas. The highest concentrations of Zanzibar red colobus, increased from 6000 vis- Zanzibar red colobus live in the Jozani Forest itors in 1995 to 12,000 in 1996, each of whom Reserve and in the agricultural areas within 2 pay a fee of $US2. km of the southern end of the reserve. The We conducted demographic and basic eco- single most important threat to this species is logical studies of this species from 1991 to habitat destruction resulting from the rapidly 1996 (Siex, 1995; Struhsaker et d., 1997; Siex increasing human population (3^1 per cent and Struhsaker, unpubl. data). During the per year) and its exponentially increasing de- course of these studies we made preliminary mand for agricultural land, firewood, charcoal surveys of two areas where this colobine was © 1998 FFI, Oryx, 32 (4), 277-284 277 Downloaded from https://www.cambridge.org/core. IP address: 170.106.40.40, on 02 Oct 2021 at 23:59:56, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1046/j.1365-3008.1998.d01-57.x T. T. STRUHSAKER AND K. S. SIEX translocated and one where it was introduced failed introduction of Zanzibar red colobus in the 1970s and 1980s. These surveys are im- monkeys. These cases provide some insight portant because they provide information on into factors that determine the likelihood of a the relative success of translocations and in- successful translocation or introduction. troductions as a conservation tool. Translocation and introduction as approaches We are not aware of any documented cases to conservation are usually considered to be of successful translocations or introductions of two of the last and relatively desperate op- African forest monkeys within mainland tions; surpassed only by reintroductions or Africa. Olive baboons Papio anubis have been total reliance on captive populations. It is par- translocated successfully in Kenya (Strum, ticularly relevant in situations where rare 1987). In the course of the studies reported habitats and/or populations are being de- here, we have discovered another likely case stroyed, and where alternative and unoccu- of a successful primate introduction. This con- pied habitat exists. An important contingent is cerns the vervet monkey Cercapithecus aethiops that the translocation or introduction process on Unguja Island. Pakenham (1984) did not re- does not adversely affect plant or animal port this species as being present on Unguja species in the area into which the animals are when he worked there in 1938-45. During our being moved. Here we report data only on the studies in 1991-96, we frequently saw vervets translocated and introduced Zanzibar red in the Masingini forest and less frequently at colobus; we have no data as to the effect these Kichwele. It appears that this species is begin- translocations and introduction may have had ning to successfully colonize the western part on other species. of Unguja, where we speculate that it was ac- cidentally introduced by escaped or released pets. Similar events apparently transpired Translocation and introduction sites with the successful naturalization of C. aethiops on the islands of Barbados and St Zanzibar red colobus were translocated to two Kitts, and C. mona on the islands of Grenada, sites, Masingini and Kichwele Forest Reserves, Sao Tome and Principe. Cercopithecus aethiops located on Unguja Island. Historical data on and C. mona, like Papio spp., are considered to the vegetation of Unguja suggest that red be colonizing species that are highly adaptable colobus probably occurred naturally in both in terms of habitat use and in surviving hunt- the Masingini and Kichwele areas prior to ing pressure from humans. As a consequence, their conversion to agriculture in the 1800s releases of species with these characteristics (Pakenham, 1984). Red colobus were intro- are more likely to succeed than releases of duced to Ngezi Forest Reserve, located on more highly specialized species, such as those Pemba Island. of the genus Procolobus. The Masingini Forest Reserve is located on a Translocation usually, but not always, refers low ridge (<110 m elevation) approximately to the capture of free-ranging wild animals in 2-3 km north-east of Zanzibar town (Figure 1). their native habitat and their release into natu- This area was badly eroded prior to 1953 and, ral or near-natural habitat within their geo- because it constitutes the main water catch- graphical range. The release of captured ment for the town of Zanzibar, land was pur- animals is usually done within a few days of chased and a reforestation project was capture. Translocation is distinguished from initiated by the Department of Agriculture (in- reintroduction, which refers to the transfer of cluding Forestry). The reserve was planted captive animals (usually captive bred) into the with a wide variety of trees, most of which are wild. The problems involved with reintroduc- not indigenous to Zanzibar. Monotypic stands tions were reviewed by Caldecott and of Pinus caribaea, Tectona grandis, Eucalyptus Kavanagh (1983) and Beck et al. (1994). tereticornis and Calophyllum inophyllum, as well We report here what appear to be one suc- as small agricultural plots, occur around the cessful and one failed translocation, and one rather steep slopes and gullies, and a small 278 © 1998 FFI, Oryx, 32 (4), 277-284 Downloaded from https://www.cambridge.org/core. IP address: 170.106.40.40, on 02 Oct 2021 at 23:59:56, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1046/j.1365-3008.1998.d01-57.x TRANSLOCATION AND INTRODUCTION OF THE ZANZIBAR RED COLOBUS MONKEY • Nungwt UNGUJA ISLAND, ZANZIBAR • Masingini forest ZANZIBAR TOWN iM-- JOZANI FOREST Paje Kitogani Jambiana Figure 1. Unguja island, Zanzibar, Tanzania, East Africa. Note Jozani Forest Reserve and 5 kms. translocation areas: Masingini Forest and Kichwele. part of the ridge on the western side of the re- Bridelia micrantha and Parinari cumtellifolia. The serve. The largest part of the western ridge is red colobus translocated to Masingini have forested with a wide range of tropical hard- been seen only in the mixed-species tropical woods (indigenous and non-indigenous), in- hardwood forests and not in the monotypic cluding Maesopsis eminii, Swietenia sp., Milicia tree plantations. We estimate that the habitat (Chlorophora) excelsa, Erythrophleum suaveolens, suitable for red colobus in Masingini was Syzygium (Eugenia) cumini, Eugenia caryophyl- about 2 sq km. lus, Harungana madagascariensis, Vitex doniana, Human activities in the Masingini Reserve Artocarpus heterophyllus, Mangifera indica, include harvesting of the trees planted in © 1998 FFI, Oryx, 32 (4), 277-284 279 Downloaded from https://www.cambridge.org/core. IP address: 170.106.40.40, on 02 Oct 2021 at 23:59:56, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1046/j.1365-3008.1998.d01-57.x T. T. STRUHSAKER AND K. S. SIEX monocultures and a limited amount of cutting caria, Elaeis guineensis, Erythrophloeum suave- in the mixed hardwood forest for building olens, Pachystela brevipes, Bombax rhodog- poles and timber. Some hunting may occur, naphalon and Croton sylvaticus. Maesopsis eminii but we suspect this is primarily for duikers is an introduced exotic that is colonizing the (Cephalophus adersi and C. monticola), suni reserve so successfully as to be considered a Nesotragus moschatus and bush pigs pest (Beenjte, 1990).