Limnogale mergulus

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	MAMMALIA	AFROSORICIDA	TENRECIDAE

Scientific Name:

Limnogale mergulus

Species Authority

Major, 1896

Common Name/s:

English

–

Aquatic Tenrec

Assessment Information [top]

Red List Category & Criteria:

Vulnerable B2ab(ii,iii) ver 3.1

Year Assessed:

2008

Assessor/s

Olson, L. & Goodman, S. (IUCN SSC Afrotheria Specialist Group - Tenrec Section)

Evaluator/s:

Rathbun, G. (Afrotheria Red List Authority) & Hoffmann, M. (Global Mammal Assessment Team)

Justification:
This species is poorly known, with localities across a relatively wide area, although not many appropriate surveys have been carried out. Since this species is restricted to streams within natural forests, there is estimated to be less than 2,000 km² habitat remaining. These streams are undergoing a decline in habitat quality, especially from siltation, and the species' area of occupancy is declining. Further research is needed to determine how restricted this species is within the forested stream habitats of its range, and certainly could elevate its threat status. The species is listed as Vulnerable.

History:

2006	–	Vulnerable (IUCN 2006)
1996	–	Endangered (Baillie and Groombridge 1996)
1994	–	Indeterminate (Groombridge 1994)
1990	–	Indeterminate (IUCN 1990)
1988	–	Vulnerable (IUCN Conservation Monitoring Centre 1988)

Geographic Range [top]

Range Description:	This species is endemic to Madagascar. It occurs in the eastern humid forest and central highlands. This species has only been recorded from a few localities in Madagascar (10 sites listed in Benstead and Olson 2003), including the Antsanpandrano Forestry Station on the Ankarata Massif, a site 15 km north of Antanifotsy village (Andringitra), a site 10 km north of Andekaleka, one specimen was caught in an eel trap at Ranomafana Est, 60 km east of Fianarantsoa; and a site 35 km south of Antsirabe. Its amphibious lifestyle is an impediment to the study of its distribution, which is poorly known. The altitudinal range is 450–2,000 m. There have not been many appropriate surveys in the intervening areas between the known localities, though it is likely present in appropriate habitat.
Countries:	Native: Madagascar
Range Map:	(click map to view full version)

Population [top]

Population:	This species is only known from a few sites. Only two sites (Antsanpandrano and Ramonafana) have had repeated survey work.
Population Trend:	Unknown

Habitat and Ecology [top]

Habitat and Ecology:	This species is a semi-aquatic carnivore, occurring along streams and rivers. The main habitat requirements are permanent, clean and fast flowing water. This species is thought to feed on freshwater crayfish, aquatic insect larvae and small crustaceans. However, it has once been found in streams within a pine plantations (which potentially keep siltation down similar to native vegetation), although this does not seem to be the case in other areas within its range (S. M. Goodman pers. comm.).
Systems:	Freshwater

Habitat and Ecology:

This species is a semi-aquatic carnivore, occurring along streams and rivers. The main habitat requirements are permanent, clean and fast flowing water. This species is thought to feed on freshwater crayfish, aquatic insect larvae and small crustaceans. However, it has once been found in streams within a pine plantations (which potentially keep siltation down similar to native vegetation), although this does not seem to be the case in other areas within its range (S. M. Goodman pers. comm.).

Systems:

Freshwater

Threats [top]

Major Threat(s):	This species apparently requires clean and fast flowing water and is therefore vulnerable to siltation and soil erosion caused by deforestation. Agricultural expansion is fragmenting the upland forests, thereby isolating fast-flowing riverine habitat. Previously, collection and removal of the plant Aponogeton, which L. mergulus is closely associated with, was thought to cause an adverse reaction from the population (Nowak 1999); however, this has since been refuted (Benstead and Olson 2003). Accidental capture in fish traps has also been recorded.

Major Threat(s):

This species apparently requires clean and fast flowing water and is therefore vulnerable to siltation and soil erosion caused by deforestation. Agricultural expansion is fragmenting the upland forests, thereby isolating fast-flowing riverine habitat. Previously, collection and removal of the plant Aponogeton, which L. mergulus is closely associated with, was thought to cause an adverse reaction from the population (Nowak 1999); however, this has since been refuted (Benstead and Olson 2003). Accidental capture in fish traps has also been recorded.

Conservation Actions [top]

Conservation Actions:	This species is only known from two protected areas, Ranomafana National Park and the Andringitra National Park. The vulnerability of benthic prey communities to sedimentation implies that prevention of erosion and sedimentation is of paramount importance for conservation of this species. New and existing sites for the species must be protected from the effects of sedimentation wherever possible, either by inclusion of forested catchments in the protected areas network or by other means (e.g., effective terracing of agricultural fields and maintenance of vegetated riparian zones) (Benstead et al. 2001).

Conservation Actions:

This species is only known from two protected areas, Ranomafana National Park and the Andringitra National Park. The vulnerability of benthic prey communities to sedimentation implies that prevention of erosion and sedimentation is of paramount importance for conservation of this species. New and existing sites for the species must be protected from the effects of sedimentation wherever possible, either by inclusion of forested catchments in the protected areas network or by other means (e.g., effective terracing of agricultural fields and maintenance of vegetated riparian zones) (Benstead et al. 2001).

Citation:	Olson, L. & Goodman, S. 2008. Limnogale mergulus. In: IUCN 2008. 2008 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 19 November 2008.
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