AMPHIBIAWEB
Atelognathus reverberii
family: Batrachylidae
Conservation Status (definitions)
IUCN (Red List) Status Vulnerable (VU)
CITES
Other International Status None
National Status None
Regional Status None

Country distribution from AmphibiaWeb's database: Argentina

 

View distribution map using BerkeleyMapper.

   

From the IUCN Red List Species Account:

 

Range Description

This species is endemic to the Somuncurá Plateau, an isolated basaltic plateau in Río Negro and Chubut Provinces, in Argentinean Patagonia, at an altitude of 920-1,200 m asl (Martinazzo et al. 2011, Vaira et al. 2012). Its extent of occurrence (EOO) is estimated to be 8,404 km2 and could potentially be larger still; however, it is important to note that this frog is restricted to about 100 m of the shores of temporary lakes distributed throughout the plateau, so its area of occupancy (AOO) would likely be much smaller (F. Kacoliris pers. comm. December 2015). It is known from eight geographical localities, which are considered to be individual threat-defined locations.

Habitat and Ecology

It inhabits steppe tablelands that contain a number of temporary and semi-temporary shallow lakes scattered over the volcanic plateau (F. Kacoliris pers. comm. December 2015). It can be found under rocks and in the water, on the shores and up to 100 m of these lakes, in a transition zone between the scantily vegetated shore and the shallowly-vegetated Patagonian steppe (F. Kacoliris pers. comm. December 2015). It is a fairly terrestrial species, possibly with fossorial habits (Cei 1980). However, it is also an aquatic species that is associated to those bodies of water where it lives, especially during the breeding season (F. Kacoliris pers. comm. December 2015). Breeding takes place by larval development in permanent pools. Based on information on the congeneric Atelognathus nitoi, its reproductive output is suspected to be low (Basso et al. 2012 in Vaira et al. 2012). It is not present in modified habitats.

Population

It is considered to be a rare species. Surveys conducted in the Laguna Azul area of the Plateau in early 2015 found eleven dead individuals in a water pit (Akmentins et al. 2015, Arellano et al. 2015). A subsequent visit to the area in March 2015 found about half of over 100 individuals in a weakened state and about 10% were deceased (Arellano et al. 2015). Given the species' very low dispersal ability, the fact that it is naturally restricted to lakes and their shores, and that 100% of its area of occupancy (AOO) is found in fragmented and isolated habitat patches, it is considered to be severely fragmented following IUCN definitions (F. Kacoliris pers. comm. December 2015).

Population Trend

decreasing

Major Threats

The major threat to this species is human use of water resources: local inhabitants dig water pits on the shores of lakes in which the species occur to extract water for domestic and agricultural use (F. Kacoliris pers. comm. December 2015). These pits can cause the death of hundreds of frogs, who enter the pits likely for reproductive purposes, but then drown in their attempts to get out (Akmentins et al. 2015, F. Kacoliris pers. comm. December 2015). In early 2015, 441 individuals were found trapped in a human-dug water pit for human and cattle consumption, of which eleven were dead (Akmentins et al. 2015, Arellano et al. 2015). While the extent of this threat is unknown, its local effects could be significant (F. Kacoliris pers. comm. December 2015). 

Another important threat is livestock. While there are few animals (cows, sheep, goats and horses) per ranch, given the relative scarcity of water bodies in the region, livestock tend to converge at the same water bodies (F. Kacoliris pers. comm. December 2015). As they drink and feed on shore plants they trample the vegetation, cause the eutrophication of the aquatic habitat, and loss of sites for shelter (F. Kacoliris pers. comm. December 2015). While the impact of this activity has not been assessed, it does not appear to be significant (F. Kacoliris pers. comm. December 2015).

Chytrid fungus Batrachochytrium dendrobatidis has recently been reported for this species, and at potentially high rates (Arellano et al. 2015). However, its impact on the species is currently unknown (F. Kacoliris pers. comm. December 2015).

Finally, the drying up of water bodies could also pose a threats to this species. While this is an process that could be affected by climatic changes, there are currently no studies to assess its imapct on this area (F. Kacoliris pers. comm. December 2015).

Conservation Actions

Conservation Actions
Almost half of the entire population of this species is included within the Somuncurá Provincial Reserve (F. Kacoliris pers. comm. March 2016).

Conservation Needed
However, the Reserve requires improved management, since it affords no real protection for the area. The Somuncurá Plateau is home to at least one other threatened amphibian (Pleurodema somuncurense) and fish (Naked Characin) species, so the development of an area-based management plan would be helpful. Species-specific actions include the creation of artificial ponds associated to water pumps (two such ponds have already been created, F. Kacoliris pers. comm December 2015), fencing off key part of lakes to prevent livestock from entering, and fencing of water wells used by the location population to stop frogs from falling into them (in process of implementation) (F. Kacoliris pers. comm December 2015).

Research Needed
A study of human uses of the plateau's lagoons has been suggested to inform conservation action (Basso et al. 2012 in Vaira et al. 2012).


Red List Status

Vulnerable (VU)

Rationale

Listed as Vulnerable because its extent of occurrence (EOO) is estimated to be 8,404 km2, it is considered to occur in eight threat-defined locations, its population is considered to be severely fragmented, and there is a continuing decline in the extent and quality of its habitat and in the number of mature individuals in the Somuncurá Plateau.

Citation

IUCN SSC Amphibian Specialist Group 2016. Atelognathus reverberii. The IUCN Red List of Threatened Species 2016: e.T2297A85301943. http://dx.doi.org/10.2305/IUCN.UK.2016-1.RLTS.T2297A85301943.en .Downloaded on 12 December 2018

 

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