Sus verrucosus ssp. blouchi 

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
Animalia	Chordata	Mammalia	Cetartiodactyla	Suidae

Scientific Name:	Sus verrucosus ssp. blouchi
Species Authority:	Groves, 1981
Parent Species:	See Sus verrucosus
Common Name(s): English – Bawean Warty Pig

Assessment Information [top]

Red List Category & Criteria:	Endangered D ver 3.1
Year Published:	2016
Date Assessed:	2016-01-15
Assessor(s):	Rademaker, M.
Reviewer(s):	Meijaard, E.
Justification: Listed as Endangered because it has a very small and restricted population numbering less than 250 mature individuals. The Bawean Warty Pig is endemic to Bawean Island in the Java Sea and the total population size has been estimated at 177-377 individuals, with an average of 230 mature individuals (the average is likely to be an underestimate as it based on the assumption that all adult individuals contribute to reproduction).

Geographic Range [top]

Range Description:	The Bawean Warty Pig is endemic to Bawean island in the Java sea. The island is located around 150 kilometres north of the coast of east Java and has a surface area of approximately 200 km2. There are five forested areas remaining on the island, totaling approximately 47 km2. These five areas are protected and together form the Bawean Nature Reserve (BNR). Camera trapping surveys in 2015 indicated that the Bawean Warty Pig occurs in the three largest BNR areas: Gunung Besar, Kumalasa and Payung-Payung (Rademaker and Rode-Margono 2015). As all five BNR areas are separated by only a few kilometres of rice fields, villages and community forests, it cannot be ruled out that pigs irregularly visit the two smaller BNR areas, Deneden and Alas Timur. However, interviews with villagers around Alas Timur support camera trap data that pigs are not present. The Bawean Warty Pig is not known to occur on any of the small peninsulas surrounding Bawean.
Countries occurrence:	Native: Indonesia
Additional data:	♦ Estimated area of occupancy (AOO) - km2: 44 ♦ Continuing decline in area of occupancy (AOO): Unknown ♦ Extreme fluctuations in area of occupancy (AOO): Unknown ♦ Estimated extent of occurrence (EOO) - km2: 95 ♦ Continuing decline in extent of occurrence (EOO): Unknown ♦ Extreme fluctuations in extent of occurrence (EOO): Unknown ♦ Continuing decline in number of locations: No ♦ Extreme fluctuations in the number of locations: No ♦ Lower elevation limit (metres): 50 ♦ Upper elevation limit (metres): 600
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	Total population size of the Bawean Warty Pig through the use of camera traps and Random Encounter Model (REM) methodology has been estimated at 177-377 individuals (Rademaker et al. in review). For both male and female individuals the age at which sexual maturity is reached and the age at which reproduction halts are unknown. Therefore, the ratio between juveniles and adults (0.83) was used to estimate the number of mature individuals. This resulted in a  range of 147-313 mature individuals, with an average of 230 mature individuals. The average is likely to be an underestimate as it based on the assumption that all adult individuals contribute to reproduction.
Current Population Trend:	Unknown
Additional data:	♦ Number of mature individuals: 147-313, 230 ♦ Continuing decline of mature individuals: Unknown ♦ Extreme fluctuations: Unknown ♦ Population severely fragmented: No ♦ No. of subpopulations: 0 ♦ Continuing decline in subpopulations: Unknown ♦ Extreme fluctuations in subpopulations: Unknown ♦ All individuals in one subpopulation: Yes

Habitat and Ecology [top]

Habitat and Ecology:	Bawean Warty Pigs prefer community forests, here coded as rural gardens, over secondary forest, shrubland-and-degraded forest and teak stands (Rademaker et al. in review). The community forests occur at the edges of the protected areas and the other habitat types occur inside the protected areas. The preference for community forests has been hypothesized to be related to the availability of energy rich and easily accessible foods compared to the other three habitat types.
Systems:	Terrestrial
Continuing decline in area, extent and/or quality of habitat:	Yes
Movement patterns:	Not a Migrant

Use and Trade [top]

Use and Trade:

Although the species is hunted, this is done mainly in retaliation for crop-raiding or crop-protection. The carcasses are not used or traded, but left for semi-feral dogs or burned.

Threats [top]

Major Threat(s):

The main threat to the Bawean Warty Pig is posed by retaliatory hunting for crop-raiding. This includes infrequent hunts consisting of a hunter alone or with several dogs entering the protected areas and actively hunting for pigs. The exact effects this has on the population is unknown as no data have been systematically recorded on the hunting activities. Due to its infrequency and generally low occurrence the impact is still considered to be low.However, the protected areas where Bawean Warty Pigs occur are already quite small, with the largest estimated at 32 km2 and the other two at 7 km2 and 4 km2 respectively. Indirect effects on the population such as reduced reproduction resulting from these hunting activities are therefore highly likely to occur. Moreover the total lack of enforcement on pig hunting inside protected areas means that if hunting pressure were to increase, this could quickly result in serious impacts on the population given the already small population size and very restricted range.Next to hunting, illegal logging and burning occurs on a small scale within the protected areas. However, contrary to hunting, these illegal activities are addressed by the local authorities. The main reason these activities are still ongoing is due to a lack of clear protected area boundaries and confusion on the exact legality of the current extent of the protected areas itself due to procedural problems when the area was established (Nur Syamsi pers. comm.).

Conservation Actions [top]

Conservation Actions:

The species is not protected by national law. Conservation activities focused on the Bawean Warty Pig were established in 2015 through a combined research and education and awareness project focusing on all endemic taxa on Bawean. However, the length of the project was restricted to a single year. Although the activities solicited positive response from the local communities, its potential to continue is still uncertain. Retaliatory hunting following crop-raiding remains the primary threat towards the species and results in negative perceptions of Bawean Warty Pigs in local communities. The conservation actions most urgently needed are effective enforcement towards illegal hunting within the protected areas, but this will likely have little effect if the underlying tensions caused by crop-raiding are not addressed. Therefore education and awareness activities should continue and low-cost, non-lethal crop protection measures against pigs should be initiated. Next to this, it is important to start systematic documentation of the hunting pressure on the pigs to be able to assess its impact on the population. This would also require collecting additional information on life history traits such as reproduction and generation length. A genetic study is urgently needed to clarify the taxonomic status of the Bawean Warty Pig and the consequences this will have for potential future ex situ management.