|Scientific Name:||Lontra provocax|
|Species Authority:||(Thomas, 1908)|
Lutra provocax Thomas, 1908
|Taxonomic Notes:||Lontra provocax had been considered a subspecies of L. canadensis (Davis 1978). It was placed in the genus Lontra by van Zyll de Jong (1987). Koepfli and Wayne (1998) and Bininda-Emonds et al. (1999) supported the separation of New World otters into genus Lontra from Lutra, except Pteronura.|
|Red List Category & Criteria:||Endangered A3cd ver 3.1|
|Assessor/s:||Sepulveda, M., Franco, M., Medina, G., Fasola, L. & Alvarez, R.|
|Reviewer/s:||Hussain, S.A. & Conroy, J. (Otter Red List Authority)|
This species is considered to be Endangered due to an inferred future population decline due to habitat loss and exploitation. Accelerating habitat destruction and degradation throughout the southern river otter's range is the greatest threat to the species, and is inferred (based on current trends) to lead to a future >50% reduction in population size over the next 30 years (3 generations) for those populations using rivers and lakes (freshwater habitats). Those populations using the southern fjords and islands (marine habitats) of Chile the population may reduce to 50% over the next 30 years due to the use of intensive fishery activities. The distribution of the southern river otter has declined drastically due to combined pressures from the destruction of habitat, removal of vegetation, river and stream canalisation, and extensive dredging. Poaching is still a problem especially south of 43° S latitude and in Tierra del Fuego where there is practically no control of hunting. Extirpation of the river otter began in local basins but has become widespread. The lack of re-establishment of the species probably is due to high mortality or reproductive failure following the dispersal of otters into unsuitable areas. This is resulting in a population that is becoming increasingly fragmented and more susceptible to local extinctions through hunting, habitat destruction, human disturbance, predation by domestic dogs, and demographic or environmental stochastic events. Therefore the present status of southern river otter must be considered precarious.
|Range Description:||L. provocax occurs in Argentine and Chilean Patagonian region, between 36°S and 52°S latitude (Chehebar et al. 1986). In Chile, the southern river otter is found from Mahuidanche river (39°S) in the province of Colchagua to the Strait of Magallanes. L. provocax once had an extensive distribution from the Cauquenes and Cachapoal Rivers to the Magellan region in Chile. Currently, the distribution of L. provocax is limited by habitat degradation and human disturbance (Medina 1996). In Argentina, the southern river otter is present along the Andes from the southern part of the province of Neuquen down to Tierra del Fuego (Cabrera 1957; Redford and Eisenberg 1992).|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||L. provocax is rare in Lanin, Puelo, and Los Alerces National Parks (Chehebar et al. 1986). Only three core populations remain in the species range: Nahuel Huapi National Park, the coast of Beagle Canal in the Tierra del Fuego National Park, and on Staten Island (Chehebar 1985; Porro and Chehebar 1995). Density of southern river otters averages 0.73 individuals (range 0.71-0.75) per km of coastline in southern Chile (Sielfeld 1992).|
|Habitat and Ecology:||
L. provocax is predominantly a freshwater species occurring in freshwater lakes and in rivers and streams. Rest and den sites are found in areas with dense vegetation and an abundance of above-ground roots, small rocks or broken stones, which provide suitable crevices from which the animal can view the adjacent water without being exposed. In the Nahuel Huapi National Park, there were significant heterogeneities in its distribution between river basins, between habitats, between lakes relative to dispersal routes and topography. Their distribution is governed by the distribution of crustacean prey, absence of human habitation, and the presence of introduced American mink Mustela vison, because although there was a positive relationship between the occurrence of mink and huillin in Lake Nahuel Huapi, there was a negative relationship in their occurrence between other lakes.
It also occurs in marine habitats along southern Chile (Sielfeld 1983). Habitat in the Patagonian archipelago consists mainly of rocky coasts and canals protected from waves, where coastal strips of vegetation such as Drimis winteri, Notofagus betuloides, and Maytenus magellanica are present; these features, as well as reduced human disturbance, are thought to be favorable for the establishment of dens (Chehebar et al. 1986; Medina 1996a, 1996b; Sielfeld 1983). In Argentina, L. provocax is associated with dense mature forest with thick undergrowth extending close to shore. Both the above-ground root systems of mature or fallen trees and the dense vegetation cover are important components of L. provocax habitat; absence of these key features may result in absence of otters, even if abundance of prey is not limiting (Chehebar et al. 1986).
The southern river otter diet consists mainly of fish including such species as Cheridon australe, Cyprinus carpio, Galaxias, Notothenia, Oncorhynchus mykiss, Percichthys trucha, Percillia gillissi, Salmo trutta, as well as some crustaceans including Aegla, Camilonotus, Lithodes antartica, Munida, Paralomis granulosa, Parastacus pugnax, and Sammastacus spinifrom. Opportunistic consumption of mollusks (Diplodon chilensis, Fissurela) and birds has also been reported (Chehebar 1982; Chehebar and Benoit 1988; Medina 1996a, 1996b, 1997; Sielfeld 1983).
Breeding is thought to occur in July and August, and young are born in September and October (Housse 1953). In parts of the species? southern range, young can be observed all year (Parera 1996). Litter size average one or two young, but may litters of up to four young have been observed (Sielfeld 1983).
The southern river otter population has been confirmed from seven isolated areas all of which are threatened by a variety of factors. It has been exterminated through much of its Chilean range by habitat destruction and disturbance through removal of riverbank vegetation, dam construction, river and stream canalization, drainage for agriculture and dredging, as well as excessive hunting practices (Chehebar et al. 1986; Housse 1953; Medina 1996a, 1996b; Porro and Chehebar 1995). Populations have been confirmed in only seven isolated areas all of which are threatened by the above-listed concerns, especially dredging impacts on coastal morphology and the large scale of forest destruction in southern Chile that may be affecting several of the freshwater habitats through severe flooding and deposition of soil on the river beds. While illegal, hunting continues to be prevalent in Chile, particularly south of the Chiloe region, as a single otter pelt may pay the equivalent of 2-3 months wages for an unskilled worker (Miller et al. 1983). Otters are also harvested illegally with shellfish-baited hooks, puyero nets, lances, shotguns, foothold traps, and dogs (Medina, 1996b). Introduction of salmonid species may have an impact on otter diet as they may out compete native fish species and salmonids may be too fast for L. provocax to catch (Chehebar 1985; Chehebar and Benoit 1988; Medina 1996a). Impacts of this shift in prey fish species require further research.
Concern about competition for food and space between Lontra provocax and the introduced American mink Mustela vison was raised when otter abundances were noted to be lower in areas where American mink were present (Chehebar 1985; Chehebar et al. 1986). It has been concluded, however, that competitive effects are unlikely to pose a major threat to the otter as the two species exhibit low overlap in diet (<26%) and habitats used (5-22%), suggesting that they may coexist with little competition (Chehebar and Benoit 1988; Chehebar et al. 1986; Medina 1997). Large scale destruction of forests in southern Chile may be affecting several of its freshwater habitats through severe flooding and deposition of soil on the river beds.
Lontra provocax is listed in Appendix I of the CITES. The Chilean Red Data Book of Vertebrates lists the species as being in danger of extinction. It is also listed as Threatened in the Argentine National Wildlife List (Consejo Asesor Regional Patagonico de la Fauna Silvestre) (Porro and Chehebar 1995). Recommended conservation measures include population monitoring, enforcement of anti-poaching legislation, habitat maintenance to conserve abundant mature plant cover along shorelines and establishment of water use restrictions for fishing and boating access (Chehebar 1985; Porro and Chehebar 1995, 1996).
Reintroduction of southern river otters into areas where they were previously exterminated due to excessive hunting could be successful in the above mentioned enforcement of legislation and monitoring programs are carried out (Porro and Chehebar 1995; Medina 1996a). Conservation of the southern river otter will require better education, time allowance for populations to recover, and re-establishment of populations in native habitat (Medina 1996a, 1996b).
|Citation:||Sepulveda, M., Franco, M., Medina, G., Fasola, L. & Alvarez, R. 2008. Lontra provocax. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 21 May 2013.|
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