Brookesia exarmata 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Reptilia Squamata Chamaeleonidae

Scientific Name: Brookesia exarmata Schimmenti & Jesu, 1996

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(iii) ver 3.1
Year Published: 2011
Date Assessed: 2011-01-27
Assessor(s): Jenkins, R.K.B., Andreone, F., Andriamazava, A., Anjeriniaina, M., Brady, L., Glaw, F., Griffiths, R.A., Rabibisoa, N., Rakotomalala, D., Randrianantoandro, J.C., Randrianiriana, J., Randrianizahana , H., Ratsoavina, F., Robsomanitrandrasana, E. & Carpenter, A.
Reviewer(s): Bowles, P. & Tolley, K.
Listed as Endangered as the species has a range of 1,991 km² (being confined, as far as is known, to the Bemaraha Massif in western Madagascar) where it occurs as a severely fragmented population, and where its habitat is undergoing a continuing decline due to fire, overgrazing, agriculture and selective logging.

Geographic Range [top]

Range Description:This species is endemic to Madagascar. It is known from its type locality in Parc National Tsingy de Bemaraha (Randrianantoandro et al. 2008, Schimmenti and Jesu 1996). Within the National Park, it is known from forests at Andranopasazy, Ankily, Anjaha, Bendrao, Ranotsara and Ankilogoa (Randrianantoandro et al. 2008, Bora et al. 2010). It has also been reported from the new protected area Beanka, north of the Réserve Naturelle d'Intégrale Tsingy de Bemaraha (R. Jenkins pers. comm. June 2011). It is assumed to have a continuous distribution from the northern bank of the Manambolo River to at least the dry deciduous forest east of Maintirano (R. Randrianavelona pers. comm. Jan 2011). Additional surveys are required within the rarely visited Réserve Naturelle d'Intégrale Tsingy de Bemaraha and dry deciduous forest east of Maintirano to verify its total distribution, but it seems unlikely that the species will range much more widely than the Bemaraha Massif, suggesting that it has a total extent of occurrence around 1,991 km². This species is known to occur between 100 and 563 m above sea level.
Countries occurrence:
Additional data:
Number of Locations:1
Lower elevation limit (metres):100
Upper elevation limit (metres):563
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Population density varies between 3.8 and 60.1 animals per ha (Randrianantoandro et al. 2007). Overall, it appears more common in the north of the park (18.7/ha) than the south (2.9/ha). The population may be both declining and severely fragmented, as unprotected forest to the north of the park is declining and occurs only as remnant patches.
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This small species inhabits dry deciduous forest and sub-humid vegetation in areas dominated by limestone (karst) rock outcrops (Randrianantoandro et al. 2008, Schimmenti and Jesu 1996). Although there is no information on wild individuals, like other Brookesia chameleons (Raxworthy 1991), it is believed to forage in the leaf litter during the day. This is supported by observations on captured individuals that were active on both the leaf litter and vegetation (Schimmenti and Jesu 1996). At night, it roosts above ground on small perches (1-3 mm diameter; Schimmenti and Jesu 1996) where it remains inactive until just before dawn. These perches are typically close to the ground (average = 0.13 m) and are lower than used by the two larger Brookesia species that are also found in the area (Randrianantoandro et al. 2007). The distance moved between consecutive night perches is small (0.3-0.7 m) and this is reflected in a similarly small surface area (0.2 ha) between different perch sites (Randrianantoandro et al. 2007). This species co-occurs with two other Brookesia species but appears to prefer areas of forest with relatively little understorey, high leaf litter cover and rocky outcrops (Randrianantoandro et al. 2008). It has a clutch size of two large eggs (Schimmenti and Jesu 1996).

Use and Trade [top]

Use and Trade: There is no recorded international trade in this species. Although illegal collection of reptiles has occurred in Bemaraha, and may be ongoing in parts of the reserve, B. exarmata is unlikely to be targeted.

Threats [top]

Major Threat(s): This species appears to be restricted to a forested karst outcrop in western Madagascar and although most of its known habitat is either already protected, or soon will be, it its likely that even small alterations to the vegetation structure may pose a threat (Randrianantoandro et al. 2008). Activities that threaten the forest habitat in its range include fire, overgrazing, conversion to agriculture and selective logging (Randrianantoandro et al. 2008). All of these represent future threats to the national park, but are already ongoing around the periphery and in the remainder of its range, including the fragmented forests of the Réserve Naturelle where protection is not enforceable due to bandit activity (R. Jenkins pers. comm. June 2011). This species is not thought to be threatened by the collection for international trade (Carpenter and Robson 2005, Randrianantoandro et al. 2008).

Conservation Actions [top]

Conservation Actions: This chameleon is known from Parc National Tsingy de Bemaraha and from the Beanka new protected area. It probably occurs within Réserve Naturelle d'Intégrale Tsingy de Bemaraha. However, these sites face ongoing degradation from human and natural (e.g., cyclones) causes and the retention of relatively intact forest is probably key to the survival of this species. Therefore, the establishment and management of further protected areas is recommended. Research should be carried out to clarify the full distribution of this species. International trade in species of this genus is controlled under CITES Appendix II.

Citation: Jenkins, R.K.B., Andreone, F., Andriamazava, A., Anjeriniaina, M., Brady, L., Glaw, F., Griffiths, R.A., Rabibisoa, N., Rakotomalala, D., Randrianantoandro, J.C., Randrianiriana, J., Randrianizahana , H., Ratsoavina, F., Robsomanitrandrasana, E. & Carpenter, A. 2011. Brookesia exarmata. The IUCN Red List of Threatened Species 2011: e.T176295A7211804. . Downloaded on 21 September 2018.
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