This species is listed on CITES Appendix I (CITES 2000). It is protected from hunting not just on paper, but effectively in practice (G. Semiadi pers. comm. 2008). It inhabits Bawean Island Nature Reserve (5,000 ha; the island is 200 km² in size), established in 1979 for which a management plan prepared in 1979 (WWF 1979; Blouch and Sumaryoto 1987) warrants revision. Management activities have included termination of hunting, controlled burning of grassy areas within forests, and thinning of teak plantations to encourage understorey development (Blouch and Sumaryoto 1987). Since 2000 a captive breeding programme has been operative on Bawean; in 2006 it involved a founder population of two stags and five hinds, and by 2014 numbered 35 animals (Meijaard et al. 2014). About 300–350 animals are held in zoos and private captive breeding facilities off the island (G. Semiadi pers. comm. 2006).
Recommended conservation actions, which should proceed through appropriate revisions to the management plan, include:
1) Increase the populations and if possible expand the area used by the deer. While the population seems to be stable, its small size and insular nature leave it susceptible to chance events (e.g. weather-related disasters or earthquakes or disease), to any resumption of hunting and probably to inbreeding. Increasing Chromolaena will result in time in population decrease. There is thus a major role for active management of habitat through control of Chromolaena, so as to increase population density within the protected area, and thus total population. This species, a problem plant throughout much of South and South-east Asia, is very difficult to control and review of international successes and failures is needed to inform management of the weed on Bawean. Full security would come only through an increase of the range on the island, requiring some deer-centred management for areas outside the protected area.
2) Assess the impact of deer on crops as this may have become a problem if effective protection has allowed the population to increase substantially, or the invasion of Chromolaena is pushing deer to eat more crops. If so, community-based mediation with local conservation officials may be required to find solutions and mitigate conflict.
3) Initiate a co-ordinated breeding programme to evaluate and if necessary address possible inbreeding deficiencies in the captive population.
This species is endemic to Bawean Island (= Pulau Bawean), in the Javan Sea off the northern coast of Java, Indonesia (Lachenmeier and Melisch 1996, Grubb 2005). Two main parts of the island are used, the central mountain range, and Mount Bulu in the south-west (Blouch and Atmosoedirdjo 1978, 1987). Tanjung Cina (= Cina Cape), an area of 950 m x 300 m, which has hilly topography in its centre and no resident human population, lies at the north-west of Bawean Island and is often cut off from the main island by a sea level of 20–150 m; it has been much used by Bawean Deer since at least the 1990s (Semiadi 2004).
Today’s restriction to Bawean is a relict from occurrence on Java, probably into the Holocene (van den Brink 1982), its disappearance from Java perhaps being caused by competition with Javan Rusa Rusa timorensis and Southern Red Muntjac Muntiacus muntjak (Meijaard and Groves 2004).
A specimen in the Institute of Zoology, Beijing, is labelled from Bangka Island, which lies off Sumatra (Indonesia); this is presumably in error (Grubb 2005). The species was supposedly discovered by Salomon Müller in 1836 in Tuban, a small town on the northern coast of Java, where the local governor kept a small herd in his garden, and the native range was discovered only after the name was proposed (Sitwell 1970). The species presumably evolved from a Pleistocene Javan Axis species (perhaps Axis lydekkeri) at a time when Bawean was connected to Java via a land bridge (Blouch and Atmosoedirdjo 1987, Meijaard and Groves 2004). Suggestions that the genus was introduced to Bawean by early European settlers seem unlikely (Sitwell 1970) because of the wealth of fossil material (reviewed in Meijaard and Groves 2004), and were not ever referred to by Grubb (2005).
Bawean Deer was reported as 'plentiful' during the 19th century. The population increased in the 1950s in response to forest protection, declined during the 1960s–1970s (Grimwood 1976), although no estimates are available, and in the 1980s was thought to number around 300 animals and to be increasing once again (Blouch 1980, Blouch and Atmosoedirdjo 1987). Through a 1991 survey the deer was suspected to be in decline (Gunawan and Kustanto 1994). In 2006, the wild population was estimated (based on field-work in 1998–2003) to be stable at 250–300 animals (Semiadi 2004, G. Semiadi and S. Pudyatmoko pers. comm. 2006), but there has been no systematic survey; 500 would be an absolute maximum (G. Semiadi pers. comm. 2008). Secondary forest seems to be the ideal habitat, supporting up to 19.2 deer per km2 (Blouch and Atmosoedirdjo 1978). Teak Tectona grandis forests with understorey, primary forest, and areas with teak and lalang support densities of 3.3 to 7.4 deer per km2, while regions dominated by Melastoma polyanthum and Eurya nitida brush, Rombok Merremia peltata, disturbed primary forest, and teak without understorey support only 0.9-2.2 deer per km2 (Blouch and Atmosoedirdjo 1987). The most recent assessment is in Semiadi (2004), who drew attention to the wet-season densities of 11.8 animals per km2 on Tanjung Cina (= Cina Cape). In 2013 ranger patrols suggested the distribution of deer has not changed (Nursyamsi pers. comm. 2014).
Bawean Deer has been subject to uncontrolled hunting, probably since human settlement took place some 500 years ago. During the 1960s much forest on Bawean was replaced by teak plantations; coupled with increased hunting pressure, this probably caused the species to decline in numbers. Hunting ceased in 1977, and the population increased during the next few years (Anonymous 1978, Blouch and Sumaryoto 1987, G. Semiadi pers. comm. 2006). The hunting of pigs Sus scrofa with dogs persists, and leads to inadvertent death of deer (G. Semiadi pers. comm. 2006), but at the population level hunting is no longer a threat (G. Semiadi pers. comm. 2008). Presently, fewer than five deer die per year through direct human influence, chiefly in traffic accidents and when being chased by local dogs during pig hunts (G. Semiadi pers. comm. 2008). Maturation of teak (including coppicing from cut stumps) and invasion by the American herb Chromolaena odorata; Compositae (=Eupatorium odoratum) constitute the only significant predictable threat to this deer, through reducing the grazing areas and this carrying capacity (G. Semiadi pers. comm. 2013). Pigs (Sus spp.) may be impacting the re-growth of grass and other foodplants in grazing areas, which could pose a threat to the Bawean Deer population (G. Semiadi pers. comm. 2014) but this is not confirmed. For a population at best on the edge of the oft-quoted, though somewhat arbitrary, minimum figure for a population viable into the long term (500), such a further reduction (on top of the major contraction in available habitat for the species over past centuries) should be seen as a major threat despite recent population stability.
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Roland Wirth (category and featured image)