Sus oliveri 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Cetartiodactyla Suidae

Scientific Name: Sus oliveri Groves, 1997
Common Name(s):
English Oliver's Warty Pig
Taxonomic Notes: This taxon was recognized as a separate species from Sus philippensis according to Groves (2001). It is known from four skulls and a mounted head collected in 1993 now in the Field Museum, Chicago, which constitutes the holotype (Grubb 2005, W. Oliver unpublished).

Assessment Information [top]

Red List Category & Criteria: Vulnerable B1ab(iii,v)+2ab(iii,v) ver 3.1
Year Published: 2016
Date Assessed: 2015-11-01
Assessor(s): Schütz, E.
Reviewer(s): Meijaard, E.
Contributor(s): Oliver, W.R.T.
Sus oliveri has a distribution restricted to the island of Mindoro. Although restricted in range, the extent of occurrence (EOO), based on current known range, considerably exceeds the threshold of 5,000 km² to warrant listing as Endangered under criterion B1. Estimated area of occupancy (AOO), based on maps of approximate distribution and apparent availability of suitable habitat, measures between 1,500 and 1,700 km², although there is uncertainty with this figure. Hence, the species is here listed as Vulnerable, because its EOO is 6,100 km² and its AOO is less than 2,000 km², its distribution is severely fragmented, and there is a continuing decline in the extent and quality of its habitat, and in the number of mature individuals due to hybridisation and over-hunting.
Previously published Red List assessments:

Geographic Range [top]

Range Description:Oliver's Warty Pig is endemic to the Philippines Island of Mindoro (Heaney et al. 1998) where it was previously widely distributed and common. Surveys conducted since the late 1990s indicated the species is now mostly confined to higher elevations in the central and north-western mountain ranges. Although still reported as common by local Mangyan (indigenous) and non-indigenous communities, encounters with the species are becoming less frequent. Most of the unconfirmed reports as well as tracks and visual observations were limited to areas adjacent to or inside forest habitats. Recent observations confirmed the presence of the species in the east (Bongabong River watershed) and west side  (Anahawin, Lumintao and the upper Kinarawan River watersheds), the Aruyan-Malati Tamaraw Reservation Area (Sablayan District), of Mts Iglit-Baco National Park, Mt. Halcon, Mt. Wood, Siburan Forest and Tusk Peak, as well as Mt. Calavite Wildlife Sanctuary and most probably Mt Malasimbo in the north of the Island.
Countries occurrence:
Additional data:
Estimated area of occupancy (AOO) - km2:1600
Continuing decline in extent of occurrence (EOO):Unknown
Number of Locations:1
Lower elevation limit (metres):800
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Its population size is unknown, but the population is fragmented and most probably declining.
Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Yes
Population severely fragmented:Unknown

Habitat and Ecology [top]

Habitat and Ecology:

Formerly this species was found in forests (primary and secondary) as well as most other habitat types, from sea level to upper montane and mossy forest areas. It now occurs in lowland, mid-montane and dry-molave forests and savannah grasslands (Gonzalez et al. 1999), but mostly it is restricted to higher elevations above 800 m asl. (Oliver 2008, Heaney et al. 2010). Recent surveys observed tracks and wallows in primary and secondary forests, creeks, river banks, grassland, swamps, and croplands from residing indigenous people, from 240 to 1700 masl (Schütz 2014), with lower frequency at lower altitudes. Observations suggest that, within Mts Iglit-Baco National Park and surrounding areas, the species remains frequent in areas where local indigenous people maintain traditional land-use practices such as slash and burn agriculture (kaingin) (Schütz 2014).

Very little information is available on the ecology of the species. It is presumed that the species feeds on wide variety of plant and animal matter such as tubers, fallen fruit and invertebrates similar to the closely related S.philippensis. Local communities in Mt Calavite report wild pigs raiding indigenous upland crops fields (kaingin) planted with root crops (D.G. Tabaranza pers. obs). There is no information available on breeding biology, habitat preferences, territory range, behaviour as well as on population size of the species. 

Continuing decline in area, extent and/or quality of habitat:Yes

Use and Trade [top]

Use and Trade: The species is a traditional source of meat for the indigenous communities living in the mountainous interior of Mindoro. It is also a source of bushmeat for lowlander settlers. Trade of Warty Pig's bushmeat remains at a local scale among poachers and residing villagers (E. Schütz pers. comm. 2014).

Threats [top]

Major Threat(s): The main threats to the species include widespread destruction of former forest habitats with continuing decline in quality in most areas contributing to severely fragmented distribution. Species distribution map and protected area boundaries show evident weaknesses in the existing protected areas network on Mindoro. Anomalies in local legislation pertaining to allowable hunting of threatened versus non-threatened species by local indigenous peoples. Many (perhaps most) of Mindoro’s remaining forest areas are also severely threatened by commercial mining claims and salient ‘pro-mining’ agendas by many of the relevant Philippine governmental authorities. Genetic contamination via hybridization with free-ranging domestic pigs raised by hinterland communities in Mindoro might pose the single most important threat to the genetic integrity of this species (Oliver 1992, Gonzalez et al. 1999, Oliver 2008, W.L.R.Oliver pers. comm. 2014). However, the rate of hybridization has not been studied or evaluated. The species is also widely hunted for food, local bushmeat trade and indigenous cultural ceremonies. Hunting or captures using pit fall trap, snare trap, driven hunt, spear hunt and other methods  was recently observed in many areas (Oliver 2008, Balete et al. 2013, MBCFI 2013, Schütz 2015). Hunting pressure from Mangyan communities in Mt. Calavite are somehow reduced as many indigenous communities there have been converted by missionaries to the Adventist belief which recommends abstinence from red meat including pork. Other non-indigenous, non-Adventist communities are still reported to poach wild pigs. (D.G.Tabaranza pers. obs., MBCFI 2013, E. Schütz pers. obs).

Conservation Actions [top]

Conservation Actions: The species occurs in several designated protected areas, though most of these exist only on paper. The clear exception is Mts Iglit-Baco National Park, though this area largely comprises of a former cattle ranch and therefore also largely composed of grasslands unlikely to adequately support representative biodiversity in this globally critical region. Reinforcement of existing legislation, more effective protection of the few remaining natural habitats of Mindoro, research to identify pure populations, and increased public awareness, are all needed as a matter of some urgency for the conservation of this and other Mindoro endemic species (Boitani et al. 2006, Gonzalez et al. 1999). A recent initiative to declare the Aruyan-Malati Tamaraw Reservation area as "Critical Habitat" for Tamaraw (Bubalus mindorensis) protection under national legislation shall indirectly help Sus oliveri (Schütz 2015).

Citation: Schütz, E. 2016. Sus oliveri. The IUCN Red List of Threatened Species 2016: e.T136340A44142784. . Downloaded on 25 September 2018.
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