The Role of Reintroduction in Gibbon Conservation: Opportunities and Challenges

Abstract

Gibbon populations have been declining dramatically for the past 30–40 years, primarily due to habitat destruction and fragmentation through timber felling, charcoal burning, encroachment cultivation, and general bush burning for hunting (Bodmer et al. 1991) or conversion to rubber plantations (Haimoff et al. 1987), tea and pine plantations (Nijman and van Balen 1998), and recently oil palm plantations (Curran et al. 2004). Other factors contributing to their decline include the illegal wildlife trade, the use of body parts in the manufacture of traditional medicines, and hunting for food. The majority of gibbons found in rescue and rehabilitation centers come from the illegal pet trade, though many are also rescued from plantations as forests are cut down. Gibbons in the illegal pet trade are almost always born in the wild, and infant gibbons can fetch from US $10–100 on the black market (ProFauna Indonesia, pers. comm.). This represents a great deal of money for the average family from gibbon range countries, even when the cost of a bullet and gun are considered. Therefore, trade in highly endangered gibbons continues, despite legislation against hunting throughout the gibbons’ range. Without exception, the young are captured by killing the mother (usually by shooting her) and taking the infant after the mother has fallen or when the infant comes to the ground to investigate what has happened. The subsequent conditions of captivity and transport in tiny, inadequate cages cause at least half of the infants to die in transport (Rijksen and Rijksen-Graatsma 1979; Bennett 1992; Eudey 1992; Cheyne 2004). Therefore, every infant gibbon that actually reaches the market signifies a much greater loss to the population. Not only are infants lost during capture and transport, but we must also consider as lost the future infants that