CONSERVATION STATUS
CITES: Appendix I (http://www.cites.org)
IUCN Red List: S. syndactylus: LR/nt; S. s. syndactylus: LR/nt;
S. s. continentis: LR/nt (http://www.redlist.org)
The siamang is listed by CITES in Appendix I, which lists species that are
threatened with extinction and for which international trade is prohibited
except in exceptional situations (http://www.cites.org).
Photo: Alan H. Shoemaker
The IUCN Red List classified the siamang and its subspecies in 2000 as Lower
Risk/Near Threatened (LR/nt). This means that the species has been evaluated
and does not satisfy the criteria for any of the categories critically
endangered, endangered or vulnerable. In addition, this classification means
that the species does not qualify for a conservation dependent classification,
but is close to qualifying for vulnerable (http://www.redlist.org).
However, a recent reassessment in 2006 by IUCN significantly raised the
threat level to the species. In this new assessment, siamangs are listed as
Endangered (EN A2cb) which means that the species is considered to be facing a
very high risk of extinction in the wild due to an observed, estimated, inferred
or suspected population size reduction of greater than or equal to 50% over the
last ten years or three generations, whichever is the longer, where the
reduction or its causes may not have ceased or may not be understood, or may not
be reversible. This reduction is due to a decline in area of occupancy, extent
of occurrence and/or quality of habitat and the classification explained by an
index of abundance appropriate to the taxon (Geissmann 2007).
The total siamang population for Indonesia (i.e., Sumatra) is estimated at
360,000 individuals in 1987, however there are no population estimates younger
than 20 years old (MacKinnon 1987; Geissmann 2007). Among the gibbons, siamangs
appear to be among the more able to cope with habitat degradation and change
(Geissmann et al. 2006; 2007).
CONSERVATION THREATS
Threat: Human-Induced Habitat Loss and Degradation
As in most primate species, habitat loss presents one of the most profound
and ongoing threats to the survival of the siamang. It is estimated that
siamags have lost 70-80% of their habitat in the last 50 years and the
destruction continues (Geissmann 2007). Forest clearance is usually for
agricultural land or for logging (MacKinnon 1986). There are two main ways in
which forests are logged in Southeast Asia; clear cutting and selective logging
(MacKinnon 1987). Even selectively logged forests are very poor
habitat for siamangs and other gibbons as brachiation requires a continuous
canopy (MacKinnon 1984). In recent years, illegal deforestation on Sumatra has
increased and in one survey of the southern portion of the island, almost every
forest visited had undergone or was undergoing, some degree of habitat
destruction. While able to cope with some habitat degradation, in more highly
disturbed habitats, siamangs are absent (Geissmann et al. 2006; 2007). Further,
road building has the potential to degrade siamang habitat by increasing
farming, settlement, and logging. It does this by creating opportunities for
the transportation and sale of forest products, as occurred within the borders
of the Gunung Leuser National Park on Sumatra (Palombit 1992). Finally,
traditional use of forest products by local residents is ongoing, but is small
in scale and only for personal use (Palombit 1992).
Threat: Harvesting (hunting/gathering)
Siamangs, especially young individuals, are sold in wildlife markets as pets
(often openly) even though they are a protected species. Often, these young are
taken by killing a parent who is carrying the infant, a technique that sometimes
causes the death of the young siamang as well (Crockett & Wilson 1980;
Geissmann et al. 2006). In addition to being sold and kept locally as pets,
siamangs are also sometimes exported illegally or sold elsewhere in Indonesia as
evidenced by siamangs found for sale in markets on Java (Crockett & Wilson
1980; Malone et al. 2002). Collection of siamangs as pets can result from
logging, with the animals being collected after their habitat is destroyed
(O'Brien et al. 2004).
At least in southern Sumatra, siamangs are not hunted for food, and in some
areas, religion precludes the eating of primates (Palombit 1992; O'Brien et al.
2004).
Threat: Natural Disasters
Forest fires precipitated by El Niño/Southern Oscillation (ENSO)
events also represent a threat to siamang populations. Such events are
increasing in frequency, and correspondingly, forest fires have the potential to
do so as well. Following wildfires, siamang groups are smaller and have lower
offspring survival rates, as well as fewer numbers of preferred food species
available to them (O'Brien et al. 2003).
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Content last modified: January 29, 2008
Written by Kurt Gron.
Cite this page as:
Gron KJ. 2008 January 29. Primate Factsheets: Siamang (Symphalangus syndactylus) Conservation. <http://pin.primate.wisc.edu/factsheets/entry/siamang/cons>. Accessed 2008 May 11.
