|Scientific Name:||Hypogeomys antimena|
|Species Authority:||A. Grandidier, 1869|
|Taxonomic Notes:||A second species of Hypogeomys is known from the subfossil record. H. australis was still extant 4,400 years ago, and once occurred from southeastern Madagascar north to at least the Antsirabe region (Goodman and Rakotondravony 1996).|
|Red List Category & Criteria:||Endangered B1ab(iii,v) ver 3.1|
|Assessor/s:||Durbin, J. & Goodman, S.|
|Reviewer/s:||Amori, G. (Small Nonvolant Mammal Red List Authority) & Hoffmann, M. (Global Mammal Assessment Team)|
The species is listed as Endangered, since its total range is less than 200 km², the range is fragmented, and there is continuing decline both in habitat and mature individuals due to ongoing habitat loss, hunting and potential pathogens.
|Range Description:||This species is endemic to Madagascar, where it is restricted to the west of the island in a narrow coastal zone. The southern limit is now the Tomitsy River (until recently it ranged south to the the Andranomena River) up to the Tsiribihina River in the north (Sommer 2003). In the last century, the species ranged from the Morondava River to the Tsiribihina in the north, but the species has lost significant portions of its range, and is now found in two isolated range segments (separated by the Mandroatra River). The total range is estimated to be less than 200 km². The species is found from 60-100 m asl.
Subfossil remains indicate that over the past 1400 years, the range of H. antimena extended at least 475 km further south (Goodman and Rakotondravony 1996).
|Range Map:||Click here to open the map viewer and explore range.|
Within the largest forest fragment in the southern forest area, the Kirindy Forest/CFPF, field studies between
1990 and 2000 documented a rapid population decline. Whereas the population size was constant between 1992 and 1996 (54 animals/100 ha), the population density declined by about 40% between 1997 and 1999 (33 animals/100 ha) and in 2000 by about 60% of the original density (22 animals/100 ha) (Sommer and Hommen 2000).
In a population viability analysis, Sommer et al. (2002) used a calculated median of 23 active burrows per 100 ha in suitable habitat to estimate the southern subpopulation (15,000 ha) with 6,900 adults and the northern subpopulation
(4,000 ha) with 18,40 adults.
|Habitat and Ecology:||This is the largest extant rodent on Madagascar. It inhabits dry deciduous coastal forest (mixed with baobabs) with a sandy floor permanently covered by dry leaf-litter. Animals live in monogamous social units and both sexes are territorial. The animals occupy a family burrow with a complex of tunnels. They are nocturnal, and forage on the forest floor for fallen fruit, seeds and leaves. It is also known to dig for roots and tubers and to strip bark from saplings. Mating takes place in the rainy season, and the females give birth to one young per litter; females can give birth twice within the reproductive period. Males leave the parental burrow and territory at the age of around one year (before the next breeding period) and can reproduce immediately. However, female offspring show delayed dispersal and stay with their parents for two reproductive seasons. Females are probably not sexually mature before the age of two years (Sommer et al. 2002; Sommer 2003).|
|Major Threat(s):||The historical decline of this species has been partly through climatic change leading to increased aridification of south-western Madagascar, and also the extensive modification of suitable habitat by humans since their arrival on the island. Current areas of habitat are threatened by slash and burn agriculture, charcoal production, burning for cattle pasture and logging (Sommer 2003). There is a road that now cuts through the middle of the species' range, and has divided the range. Throughout its range, increasing visits by hunters and their dogs have targeted this species. Also, this species has declined with the introduction of feral dogs and cats, by predation and also potentially transmission of lethal toxoplasmosis. This species could be susceptible to hantavirus, which has been shown in some rodents in eastern Madagascar.|
|Conservation Actions:||The new Menabe-Antimena protected area has temporary protection order and covers the entire range of the species. A successful captive-breeding programme for this species has been established by the Durrell Wildlife Conservation Trust (see Wright et al. 2003). There is ongoing research on potential pathogens, and there is a need to control feral dogs and cats.|
|Citation:||Durbin, J. & Goodman, S. 2008. Hypogeomys antimena. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 22 May 2013.|
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