|Scientific Name:||Rhinoderma darwinii Duméril & Bibron, 1841|
|Taxonomic Source(s):||Frost, D.R. 2015. Amphibian Species of the World: an Online Reference. Version 6.0. New York, USA. Available at: http://research.amnh.org/herpetology/amphibia/index.html.|
|Red List Category & Criteria:||Endangered B2ab(iii) ver 3.1|
|Assessor(s):||IUCN SSC Amphibian Specialist Group|
|Contributor(s):||Veloso, A., Charrier, A., Valenzuela, A., Úbeda, C., Velez, C., Correa, C., Soto, C., Lavilla, E., Nunez, H., Pastore, H., Mendez, M. & Díaz, S.|
|Facilitator/Compiler(s):||Angulo, A., Neam, K., Hobin, L.|
Listed as Endangered because its area of occupancy (AOO) is estimated to be 224 km2, its population is considered to be severely fragmented, and there is continuing decline in the extent and quality of its habitat in southern Chile. Although it is likely that the species may be found in additional sites and that the estimated AOO would increase as a result of this, the current assessment is precautionary given known threats and past declines experienced by the species and assuming that at least some of the potential new sites may have also been affected.
|Previously published Red List assessments:|
|Range Description:||This species is endemic to the austral forest of Chile and Argentina, although it occurs tangentially in the latter country (Soto-Azat et al. 2013). Historically, it was distributed in Chile from Concepción to Aysen Province (Río Cuervo). Currently, it can be found in at least 45 sites in Chile (Soto-Azat et al. 2013a, Darwin’s frog Conservation Strategy Workshop 2017), from Cuyinco Alto (Cordillera Nahuelbuta) to Río Cuervo, and including Chiloé and Mocha Islands. The islands that make up the Chonos Archipelago (south of Chiloé) were previously mapped as part of this species' distribution; however there are no records of it occurring there to date (C. Soto pers. comm. January 2017) and they have been removed from the map. In Argentina, it is known from Neuquén, Chubut and Río Negro provinces, where there are 11 localities with confirmed presence of the species since 2000, all of them located in two national parks, Lanín National Park and Nahuel Huapi National Park (Úbeda and Pastore 2015). It has an altitudinal range of 0–1,340 m asl (Úbeda and Pastore 2015).|
Despite the fact that the population has a widespread range, it has been found to occupy circumscribed areas within suitable habitat (C. Soto-Azat pers. comm. July 2015). Based on known spatial occupancy and individual home range (1.82 m2, Valenzuela et al. 2014), it is assumed that each site is no larger than 4 km2 (in fact, many subpopulations in Chile are known to use less than 300 m2 of forest; Soto-Azat et al. 2013a). Assuming that each of the known sites is comparable with regards to internal occupancy, the total AOO is estimated to be 224 km2. Its EOO is 160,446 km2. In Argentina, there is no evidence of range retraction. Further surveys may extend the southern limit of distribution because there are suitable habitats under the protection of national parks (Úbeda and Pastore 2015). There is uncertainty on whether there are other non-reported subpopulations within its range, particularly in between known sites and towards southern latitudes where remote areas are difficult to access and have not been thoroughly surveyed. If new subpopulations are discovered and the AOO experiences a considerable increase, a change of category to Vulnerable is possible.
Native:Argentina (Neuquén, Rio Negro); Chile (Aisén)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Historically this species was relatively abundant until the 1980s (R. Avilés pers. comm. July 2015). However there have been subsequent declines and extirpations. The subpopulation of Monumento Natural Cerro Ñielol has disappeared completely since 1980, and that of Nahuelbuta National Park and Melimoyu (Aysen region) have experienced severe declines around 2000, with just 1-2 individuals recorded in the last five years despite intense and targeted surveys (C. Soto-Azat and A. Charrier pers. comm. July 2015). |
Its population is considered to be severely fragmented as per IUCN definitions. Despite a large historial distribution, at present, the species is currently known from a very small percentage of this area in small and severely fragmented subpopulations. This species has high site fidelity (home ranges of only 1–3 m2) and dispersal limitations, and is also highly specialized, living only in certain areas within the forest forming colonies. It is only known from 56 localities (in Chile), each of them isolated and independent subpopulations (C. Soto-Azat pers. comm. August 2017).
In Chile, there are 103 recognized historical sites documented between 1834 to 2000 (evidence of historical presence was based on museum specimens). All of these sites have been recently visited and only 16 have been confirmed to still have the species (Soto-Azat et al. 2013a). The species is now known to occur at 56 sites in Chile, including the 16 historical sites at which it can still be found (C. Soto-Azat pers. comm. August 2017). Recent population estimates vary between 10-105 individuals per subpopulation, including adults and juveniles; the latter comprise roughly 25% of individuals recorded (Soto-Azat et al. 2013a, A. Valenzuela pers. comm. July 2015).
In Argentina, there are 41 recognized historical sites between 1896 to present, of which only 11 sites have evidence of the species after 2000. In this country, this is a scarce species and appears to have declined at two sites (Puerto Blest, Nahuel Huapi National Park and Villa La Angostura, Neuquén Province) during the past 50 years. Since the 1990s, specific surveys have recorded few individuals within suitable habitats (C. Úbeda pers comm. August 2017).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||This species generally occurs in the leaf-litter of temperate Nothofagus forests; it is also present in forest bogs. Surveys suggest that it is not very tolerant of habitat disturbance, having been found consistently within well-maintained native forest, and at the most within native forest where wood gathering for firewood takes place (Soto-Azat et al. 2013a). Females deposit eggs in moist and secluded areas, such as mosses and leaf-litter. When the larvae inside the eggs begin to move, adult males ingest the eggs and incubate them in vocal sacs. Larvae develop inside the male and emerge after metamorphosis. The generation length is estimated to be an average of 11 years based on reproductive ages of 6-15 years (J.C. Ortiz, C. Castro, C. Tala, R. Avilés and A. Charrier pers. comm. July 2015).|
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Generation Length (years):||11|
|Movement patterns:||Not a Migrant|
|Use and Trade:||It used to be encountered in the pet trade until the late 1990s; however, it is no longer found in trade. It is not listed on CITES (C. Soto-Azat pers. comm. July 2015).|
In the north, the main threats are pine forestry and drought, while in the south it is clear-cutting of forest and replacement of native forest with tree plantations (A. Charrier and C. Castro pers. comm. July 2015). Forest fires may also be a threat (C. Castro pers. comm. July 2015). There is recent evidence of chytridiomycosis associated to mortality at the individual level, but also with declines and potential extinction at the local subpopulation level (Soto-Azat et al. 2013b, A. Valenzuela-Sánchez pers. comm. July 2015). Volcanic eruptions may have an impact on some subpopulations (C. Soto-Azat pers. comm. July 2015) and climate change could possibly also affect a subsection of the range; however this requires further research.
In Argentina, based on the fact that the species is entirely included in national parks, there are few threats of anthropogenic origin. In the past, forest exploitation, fires, and livestock in the forest affected the habitat of this species (C. Úbeda and H. Pastore pers. comm. August 2017). Periodic volcanic eruptions do continue to affect important areas of the geographic range.
There are several protected areas in the range of the species. In Chile, it is listed as "Endangered" (En Peligro de Extinción) (Reglamento de Clasificación de Especies, Chile, 2011) and there are currently two ex situ initiatives, led by Universidad de Concepción - Zoo Leipzig (since 2009) and Zoológico Nacional de Chile - San Antonio Zoo, Texas since 2010 (C. Castro, A. Charrier pers. comm. July 2015). An in-situ initiative between Universidad Andrés Bello, Ranita de Darwin NGO, HuiloHuilo, Tantauco and Melimoyu private reserves has been implemented to investigate and provide further protection to the species (C. Soto-Azat pers. comm. July 2016). In Argentina, its range is entirely comprised of two national parks - Lanín and Nahuel Huapi - in western sectors, that have a relatively good status of conservation of its habitats.
There remains a need for improved maintenance and protection of native forest habitats, particularly in the north.
Close population monitoring of known subpopulations is required given the declines seen in suitable habitat. The potential of climate change is also required to determine the potential threat. Targeted surveys to unexplored areas with suitable habitat in between known sites as well as the more remote areas are required to determine if the species may also occur there.
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|Citation:||IUCN SSC Amphibian Specialist Group. 2018. Rhinoderma darwinii. The IUCN Red List of Threatened Species 2018: e.T19513A79809372.Downloaded on 23 September 2018.|
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