This is essentially a tropical and subtropical grassland species (Medway 1977; Oka 1998) but is highly flexible, with successful populations in forests, mountains, shrublands and marshes (Whitehead 1993; Oka 1998; Rouys and Theuerkauf 2003; Keith and Pellow 2005). It is found from sea-level to 900 m asl (G. Semiadi pers. comm.; S. Hedges pers. comm. 2008). Some populations make seasonal movements; for example, on New Guinea numbers in the border area between West Papua and Papua New Guinea peak during the wet season, whereas in the dry season many move to the interior of Papua New Guinea (Semiadi 2006).

Where hunting or other disturbance is not a big problem, Javan Rusas are primarily diurnal, gathering in large groups in open areas at night. The rut tends to involve a lot of nocturnal activity, even in undisturbed/low hunting areas (Oka 1998; S. Hedges pers. comm. 2008, based on observations in East Java). In diet it is adaptable and will eat herbs, the leaves and bark of shrubs, and even seaweed (Kitchener et al. 1990; Oka 1998; Keith and Pellow 2005), although it seems to prefer certain types of grass (Kitchener et al. 1990, Oka 1998), including in its native range (S. Hedges pers. comm. 2008). In New Caledonia and Australia, it is a threat to native trees (de Garine-Wichatitsky et al. 2005; Keith and Pellow 2005). In the Torres Strait Islands, mating occurs during spring (September?October) and calves are born in autumn (April?May). In other parts of Australia, Javan Rusa seems to breed at any time of the year, with a mating peak from late June to August, and a calving peak from March to April (Kitchener et al. 1990). In Indonesia it is said to breed all year around (Whitehead 1993), although a June?September increase in mating activity was found in Bali (Oka 1998), and in Java there is a peak of mating behaviour between July and September (S. Hedges pers. comm. 2008). Javan Rusa is more social than its congeners (Kitchener et al. 1990). Herds are segregated by sex, except during the mating season, and may comprise up to 25 individuals (Kitchener et al. 1990).

Red List Category

Red List Criteria

Version

2008

Hedges, S., Duckworth, J.W., Timmins, R.J., Semiadi, G. & Priyono, A.

Black, P.A. & Gonzalez, S. (Deer Red List Authority)

Justification

History

• 1996
  Lower Risk/least concern

The Javan Rusa is common in much of its current range (Kitchener et al. 1990; Corbet and Hill 1992; Whitehead 1993; Heinsohn 2003; Moriarty 2004). Most populations are outside the native range (Corbet and Hill 1992; Whitehead 1993; Heinsohn 2003; Moriarty 2004), including some of the most buoyant: New Caledonia (de Garine-Wichatitsky et al. 2004), Mauritius (where numerous, and an ecological problem; R.J. Safford in litt. 2008), Sulawesi and the Maluku islands (Indonesia; G. Semiadi pers. comm. 2008), Pulau Moyo (= Moyo island, a small island in the eastern part of Nusa Tenggara Timur, where deer are protected by local people; G. Semiadi pers. comm. 2008) and West Papua, Indonesia (over 8,000 estimated in Wasur National Park alone, in 1992; Anon. 1994). Conversely, populations have decreased substantially in some areas on Java, where it is a native (Semiadi 2006), including Baluran National Park which (at least in the 1990s) held the largest Javan Rusa population within its natural range. In 1996, 2,500?3,000 Javan Rusas were counted during a census when multiple teams of observers deployed simultaneously throughout deer habitat (Anon. 1996; S. Hedges pers. comm. 2008). Between 12 September 1998 and 18 January 1999, the population was thought to be greater than 1,000 head and it is very likely to have declined still further. Major declines have also occurred in Alas Purwo National Pak (S. Hedges pers. comm. 2008). Even in the 1980s?mid 1990s, Bali had very few populations, probably only one of significance: in Bali Barat National Park (S. Hedges pers. comm.. 2008). Its current status is unknown. There are probably no more than ten populations in the native range (= Java and Bali) and given the size of the Baluran population, it is implausible that there could be more than 10,000 mature individuals within the native range (which would imply a census population of about 13,000?20,000) even in the mid-1990s (S. Hedges pers. comm. 2008). There are many more animals in the introduced range, but they are not counted for the purposes of categorising the species through population size and trend on the Red List.

Decreasing

Java has highly fragmented natural habitats and has done for centuries, reflecting longstanding high human population densities. Many protected areas were established during the Dutch colonial period but from independence up until the 1970s they were largely under-funded and neglected. After hosting the World Parks Conference in 1982, the Indonesian government gazetted a swathe of national parks and more structured conservation planning began, funded by the World Bank and other donors. The focus was largely on the 'multi-function' national parks and much money was spent on infrastructure, some staff training and increased personnel. The 'lesser' protected areas such as "game reserves" and "nature reserves" still had few staff and resources, and that has continued to the present. There was some habitat loss from protected areas through illegal logging, agricultural encroachment and other offtake, but the national parks of Java (several of which contain ideal habitat for Javan Rusa and, at least into the mid 1990s, very large populations) remained remarkably intact for much of the period. During the 1980s and early to mid 1990s guns were tightly controlled and the military and police were feared and respected. The strong culture of caged bird keeping meant that hunting, including that within protected areas, was primarily for birds and some small game, through various forms of trapping, including snaring. Thus there was relatively little hunting of Javan Rusa and populations were stable or even increasing. Socio-political changes from 1997 led to a reduction in the respect for the police and military and the rise of a viewpoint that protected areas were the peoples' resources and would therefore benefit from decentralised management (M. Tyson pers. comm. 2008). This policy change, which risked a ?tragedy of the commons?, has indeed led to increased habitat destruction and poaching in the past decade. The Javan Rusa, as a large deer, is particularly threatened by this rapid rise in illegal hunting (S. Hedges pers. comm. 2008) and also by expansion of agriculture on Java and other forms of encroachment (G. Semiadi pers. comm.; S. Hedges pers. comm. 2008.). In Java, this deer is poached with snares and dogs, but mostly with guns in the late 1990s and 2000s (S. Hedges pers. comm. 2008). The Javan Rusa is now seen as a source of extra income and of animal protein by many local communities despite being legally protected (Semiadi 2006) and coupled with the decentralisation of conservation management decisions and actions, macro-economic fluctuations and reduced authority of The Law, this impedes control of illegal hunting (S. Hedges pers. comm. 2008). Poaching has reportedly reduced numbers at Baluran National Park, formerly the largest population within the native range, and more widely across Java, but data are insufficient to determine rate of decline (E. Meijaard pers. comm. 2008). Similar trends are likely on Bali. In the rest of its Indonesian range, e.g. Sulawesi, where it is introduced and thus populations are not used in assessing the Red List category, it is also heavily hunted and there were major population declines in the late 1990s, although at least on Sulawesi the population is now in slow recovery (G. Semiadi 2006 pers. comm. 2008). Poaching of this species in its native range is for meat, medicinal products (some traded internationally), handicrafts products, and, locally, pets.

During the 1980s?1990s, when poaching and land conversion were relatively well under control in Javan national parks, the chief threat to the large population of Javan Rusa in Baluran National Park was loss of grazing area to invasion by the introduced tree Acacia nilotica (Leguminosae) that converts open grassland to dense thorny scrub-forest. This plant was introduced (without adequate risk assessment) as part of an attempt to create a living fire-break around the park's grasslands, wild fire then being adjudged the major threat to the park?s monsoon forests. Since that introduction, repeated cutting of the acacia has led to coppicing into very dense thickets that contain little or no grass or other herbs and are difficult for the deer to penetrate. Thus habitat loss and poaching are now serious limiting factors in Baluran National Park, and habitat loss/degradation remains a severe long-term threat to be addressed (S. Hedges pers. comm. 2008). Lantana camara (Verbenaceae) is also a problem in Javan Rusa habitat in Baluran National Park and elsewhere on Java (S. Hedges pers. comm. 2008).

Javan Rusa occurs in several high-profile protected areas in Java. It is fully protected by Indonesian law. However, urgent measures are now required within its native range to end poaching and to secure the protected areas in which it occurs. This will require the development of cooperative programmes and new partnerships with the local human communities.