AMPHIBIAWEB
Alsodes pehuenche
family: Alsodidae
Conservation Status (definitions)
IUCN (Red List) Status Critically Endangered (CR)
CITES
Other International Status None
National Status None
Regional Status None

Country distribution from AmphibiaWeb's database: Argentina, Chile

 

View distribution map using BerkeleyMapper.

   

From the IUCN Red List Species Account:

 

Range Description

This species is currently known from six streams in the Pehuenche Valley near National Route 145, in Malargüe Department, Mendoza Province, Argentina, close to the international border with Chile (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010), between 2,000 and 2,523 m asl. There is one known photographic record from nearby Chile (V. Corbalán, G. Debandi and F. Martínez pers. comm. July 2012). Its known geographic range, herein taken as a proxy for its extent of occurrence (EOO) is estimated to be 9 km2 (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010). Given that this frog occupies only streams and swamps inside this range, its area of occupancy (AOO) is currently estimated at  ca. 5 km2, although this is likely to be an over-estimation as it is based on lower resolution satellite images for the area (V. Corbalán, G. Debandi and F. Martínez pers. comm. July 2012). While it is possible that it could also be found in streams in relatively inaccessible areas 8 km north and 3 km east of its current distribution, its presence there is so far unverified (V. Corbalán, G. Debandi and F. Martínez pers. comm. July 2012). All five streams inhabited by A. pehuenche on the Argentinean side are crossed by the National Route N. 145 highway, so for the purposes of this assessment this species is considered to occur in one threat-defined location (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010).

Habitat and Ecology

This is an aquatic species found primarily in galleries inside small permanent snowmelt streams with stony banks covered by herbaceous vegetation, but  it can also be found in ponds and swamps derived from snowmelt (V. Corbalán, G. Debandi and F. Martínez pers. comm. July 2012). The water is transparent, with relatively neutral pH and very high concentrations of dissolved oxygen (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010). It is considered to have a long metamorphic period (including more than four winters; Corbalán et al. 2011).

Population

A study conducted in January 2008 (V. Corbalán, G. Debandi and F. Martínez unpubl. data) recorded 350 metamorphosed individuals (juveniles and adults) and approximately 1,000 tadpoles of different ages along the four main streams where it is known from. At that time the estimated metamorphosed population did not exceed 500 individuals. In December 2008 the courses of three streams were modified by paving work, with the consequent drying of the original streams and mortality of individuals, including metamorphosed individuals and tadpoles at different developmental stages (about 25% of the total population). 

Population Trend

decreasing

Major Threats

It has already been impacted by paving work, which caused streams to dry and led to mortality (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010). The paved road is also considered to be a future threat given its potential to modify water quality, particularly in the lower reaches of the streams. Contaminant particles from vehicular transit could reach the highly oxygenated streams via lixiviation or winds (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010). In addition, the salt used for snow melting on the road during winter seep into the streams, potentially altering the ionic composition, conductivity and salinity of water (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010). An additional threat factor is posed by tourist waste, as tourists who visit the area leave large amounts of plastic and other non-biodegradable items in the streams, which is especially pronounced after bi-national annual meetings at the international border (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010). Furthermore, an expected increase in vehicular traffic due to road paving completion is also likely to increase domestic waste in the area (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010). The area is also impacted by domestic livestock (cows and goats), which trample on swamps and small ponds, with the potential to change the course of small shallow streams (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010).

Potential threats include the amphibian chytrid fungus Batrachochytrium dendrobatidis, which has been recorded in this species (Ghirardi et al. 2010), but its effect on the population is currently unknown (V. Corbalán, G. Debandi and F. Martínez pers. comm August 2010). Introduced trout re another potential threar, as the streams occupied by this frog flow into the Pehuenche River, which is within reach of trout (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010). Climate change could also be a potential threat to this species, as a change in the hydrological cycle could directly affect the frog population (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010). However, climate change modelling studies specific to this area still need to be carried out to determine the potential impact of climate change (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010).

Conservation Actions

From 2007 to date the Argentinean environmental authorities have been informed about this frog's risk of extinction as a result of paving the road, and mitigation actions have also been proposed (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010). In view of the pressing threats to this species and its habitat, water resource conservation is an urgent priority, as well as protection of the sites where this species is known to occur. A monitoring programme has been set up to control water quality, and several individuals have been marked with elastomers to follow their life cycle and movements (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010). Regular screenings for chytrid fungus are periodically undertaken, to determine its potential effect on this species (V. Corbalán, G. Debandi and F. Martínez pers. comm. August 2010). Further research on the potential impact of climate change on this species is needed.

Red List Status

Critically Endangered (CR)

Rationale

Listed as Critically Endangered given that its extent of occurrence (EOO) is estimated at 9 km2, with an area of occupancy (AOO) estimated at 5 km2, it is known from one threat-defined location, and there is a continuing decline in the quality of its stream habitat and in the number of mature individuals in the central Andes of Argentina.

Taxonomic Notes

Its tadpole was briefly described as belonging to Telmatobius montanus (Cei and Roig 1965), but was later re-assigned to the new species Alsodes pehuenche (Cei 1976).

Citation

IUCN SSC Amphibian Specialist Group, 2013. Alsodes pehuenche. The IUCN Red List of Threatened Species 2013: e.T56319A18136036. http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T56319A18136036.en .Downloaded on 20 November 2018

 

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