South AmericaDarwin's fox Lycalopex fulvipes

Darwin's fox

Amazonian Canids Working Group - Karen DeMatteo and Fernanda Michalski are the coordinators of the Amazonian Canids Working Group. This working group is focused on four species: the short-eared dog, crab-eating fox, bush dog, and South American foxes. Amazonian canids are similar to many carnivores worldwide whose long-term survival is threatened by a variety of direct and indirect threats, including habitat loss, expansion of hydroelectric dams, illegal hunting of prey, and diseases from domestic dogs.

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Other Names

Synonym: Pseudalopex fulvipes

English: Darwin's Fox

Spanish; Castilian: Zorro Azul, Zorro Chilote, Zorro de Chiloé, Zorro de Darwin

Mapudungun; Mapuche: Payne Guru

Taxonomic Notes

Several recent molecular studies have provided support for a monophyletic assemblage of South American endemic canids (Lindblad-Toh et al. 2005, Perini et al. 2010), with Chrysocyon and Speothos forming a sister-clade to the monophyletic south American foxes and Atelocynus. On the basis of morphology, Zunino et al. (1995) reviewed previous work and also supported clustering species within the two previous paraphyletic genera (Pseudalopex, Lycalopex) into a single monophyletic genus. They further argued that Lycalopex had priority over Pseudalopex, subsequently also supported by Zrzavý et al. (2004: 324). The only outstanding question would have been whether Dusicyon would have been a more appropriate name, since Perini et al. (2010) reported a close relationship between L. culpaeus and Dusicyon. However, we now know that Dusicyon is far outside this clade (Slater et al. 2009, Austin et al. 2013). Based on this evidence, the genus Lycalopex is used over Pseudalopex for all South American foxes, following Wozencraft's (2005) earlier treatment.

Justification

Darwin’s Fox is endemic to Chile. The species occurs on a large extent of Chiloé Island and in Nahuelbuta National Park (Jiménez and MacMahon 2004). Surveys have revealed that the species is also present on private properties with well-preserved native forests outside of Nahuelbuta National Park. Until recently these were the only known populations for the species, with the exception of a skin found in Punta Chanchán, midway between Nahuelbuta and Chiloé (Vila et al. 2004). However, the recent finding of a Darwin’s Fox killed by a dog near Gorbea (D’Elia et al. 2013) and several records in three protected areas in the Valdivian Coastal Range (Farías et al. 2014) have confirmed a larger extent of occurrence than previously reported (e.g., Jiménez and McMahon 2004). The presence of individuals has also been confirmed north of Llanquihue Lake, on the foothills of the Andes and approximately 60 km east to the coastal mountain range (J. Jiménez pers. obs.).

The Darwin’s Fox was previously classified in 2004 and 2008 as Critically Endangered based on an estimated population size of “less than 250 mature individuals with at least 90% of the population occurring in one subpopulation” (Chiloé Island) (Jiménez and McMahon 2004). New distribution information (Vila et al. 2004, D’Elia et al. 2013, Farías et al. 2014, J. Jiménez pers. obs., A. Farías pers. obs.) indicates that the extent of occurrence of the species is much larger than originally thought and clearly exceeds the threshold for listing it as threatened under criterion B. No reliable population data are available, although foxes seem to be more abundant and to occur at higher densities in Chiloé than on the mainland (J. Jiménez and A. Farías pers. obs.). A very conservative minimum estimate suggests at least 412 and 227 mature individuals occur on Chiloé and on the mainland, respectively. Based on this estimate, the species does not meet the thresholds for listing it as Critically Endangered under criterion C or for listing as Critically Endangered or Endangered under criterion D. Despite the conservative minimum estimate, it is nonetheless likely that total population size does not exceed 2,500 mature individuals and hence the species would meet the threshold for listing as Endangered under criterion C. Since the subpopulation on Chiloé very likely exceeds 250 mature individuals, it cannot meet subcriteria C2a(i) or C2a(ii). However, the combined impacts of forest loss and the risk posed by domestic dogs (especially of contracting Canine Distemper Virus, a risk supported by high seroprevalence in dog populations in areas inhabited by Darwin’s Fox [Sepúlveda et al. 2014, Acosta-Jamett et al. 2015b]), and the evidence for the impacts of these threats on populations, suggest a high likelihood that the population could undergo a decline exceeding 20% in the coming 6-8 years (two generations). Hence the species would meet the subcriteria for listing as EN under C1. It is acknowledged that this assessment might be slightly precautionary if the likelihood or rate of decline is overstated. In that case, the species would at least be listed as Vulnerable as it meets the threshold for listing as Vulnerable under criterion C, and based on the minimum estimate of subpopulation size for Chiloé would also meet subcriterion C2a(i). In summary, the species is considered to qualify for listing as Endangered under criterion C1.

Geographic Range Information

Darwin’s Fox is endemic to Chile occurring in at least two distinct populations (Jiménez and McMahon 2004). One is found in the forests of Chiloé Island, while the second population is on the coastal range in mainland Chile. The mainland population is apparently discontinuous. Until recently, the fox was known to occur only in the Nahuelbuta range (e.g., Medel et al. 1990, Jiménez and McMahon 2004). However, recent records confirm the presence of the species in the Valdivian coastal range (Vila et al. 2004, D’Elia et al. 2013, Farías et al. 2014), including at least three protected areas: Alerce Costero National Park, the Valdivian Coastal Reserve (both ca. 40°05'S, 73°30'W), and the Oncol Park (39°42'S, 73°18'W). Nahuelbuta and the Valdivian Coastal Range are separated by heavily disturbed landscapes. A recent record near Maullín (41°27'S, 73°48'W) (A. Farías, pers. obs.) suggests that the species is potentially extant between Bueno River and Maullín. Finally, a few individuals detected in 2014 north of Llanquihue Lake (40°53'S, 72°50'W, J. Jiménez pers. obs.), on the foothills of the Andes, would suggest that the range of this species is larger than thought, although it cannot be ruled out that such individuals belong to the same subpopulation as those in the coastal range. In summary, the fox is considered to be extant in the following areas (see map): Nahuelbuta-Caramávida, Lastarria, Oncol-Chanchán, Valdivian Coastal Reserve-Alerce Costero National Park and surrounding forest, Maullín and Puerto Octay. Darwin’s Fox is potentially extant in the forested areas between the Bueno River and Maullín and the forested areas north to Mehuín (between Gorbea and Chanchán records).

Population trend:Decreasing

(Click on map for more detail)

Population Information

In Ahuenco, Chiloé, Jiménez (2007) estimated a density of 0.92 foxes/km² in an area that seems to be prime for the species. In Nahuelbuta, D. Moreira et al. (pers. obs.) have recently found that foxes are patchily distributed across the landscape reaching densities of c. 0.75 foxes/km² in areas with less disturbed native forest. Foxes are described as common in Chiloé, except for the northern and eastern areas of the island (Jiménez and McMahon 2004). The presence of foxes seems to be largely explained by native forest (Moreira-Arce et al. 2015a). Farías and Jaksic (2011) report for north-eastern Chiloé (likely among the less suitable area for foxes in the island, Jiménez and McMahon 2004) that occupancy was associated with fragment size, with larger fragments mostly occupied. Moreira-Arce et al. (2015a) report occupancy of 32% for Nahuelbuta (around 10% of cameras with detections). Preliminary data from the Valdivian Coastal Reserve and Alerce Costero National Park (E. A. Silva-Rodríguez et al. pers. obs., A. Farías and Svensson pers. obs.) suggests similar detection rates than for Nahuelbuta. Genetic variability is extremely low for both populations, and despite its presumed larger population size, is lower in Chiloé than in mainland (J. Cabello et al. pers. obs.). Polymorphism in animals from Chiloé is lower than in other species (Cabello and Dávila 2014).

Jiménez and McMahon (2004) estimated that the extant Darwin’s Fox population was 78 individuals for Nahuelbuta National Park (and less than 100 for the Nahuelbuta range) and around 500 in Chiloé. For the purpose of this account a conservative approach was used to obtain an educated guess of the minimum population size of the Darwin’s Fox. Foxes were assumed to occupy 32% of the areas defined in the geographic range (see above). This number derives from the study in Nahuelbuta mentioned above (Moreira-Arce et al. 2015a), and is considered conservative especially when applied to Chiloé for three reasons. First, occupancy was not modelled at the home-range scale, but rather based on camera trap points; it is expected that increasing grain to the home range scale will also increase occupancy estimates. Second, Nahuelbuta is the northern limit of the distribution and the condition of the habitat is less favourable than in other areas such as Chiloé (J. Jiménez and D. Moreira pers. obs.), thus lower densities are expected in Nahuelbuta. Third, Nahuelbuta is located in an area that has been severely affected by land conversion (see Miranda et al. 2015), likely representing the most disturbed area within the current distribution of this fox. We then assumed that in occupied areas the density of mature foxes was 0.2 foxes/km². This number was calculated (1/488) from the largest home range (488 ha) reported in Jiménez (2007) and assumes that mature foxes do not have overlapping home ranges, an assumption that is extremely conservative as Jiménez (2007) showed high home range overlap (and a density of 0.92 foxes/km²). This procedure was equivalent to applying a density of 6.6 foxes/100 km². We did not attempt to estimate an upper limit of the population size. As a result we estimated a minimum of 412 mature individuals for Chiloé and 227 mature individuals for the areas in mainland where the fox is known to be present. If considering the areas where the fox is potentially extant, the minimum population size in mainland would approach 489 individuals.

Habitat and Ecology Information

Early research in Nahuelbuta suggested Darwin's Foxes were associated with dense forest (Jaksic et al. 1990, Jiménez et al. 1991). More recent radio-telemetry data indicate that animals are found more often in dense Araucaria-Nothofagus forest, open Nothofagus forest and occasionally in open pastures (McMahon et al. 1999). Preliminary data on camera trapping 20 km north-west of Nahuelbuta National Park indicate a similar pattern of occupancy of habitat types (J. Jiménez pers. obs.). More recently, Darwin’s Foxes in Nahuelbuta have been found to be positively associated with native forest availability, and negatively associated with roads (Moreira-Arce et al. 2015a). Positive response of foxes to fine grain habitat structure suggests commercial plantations may also provide complementary habitat and food resources for this diet-generalist species in Nahuelbuta (Moreira-Arce et al. 2015b). They have been recorded to ~1,400 m elevation in Nahuelbuta (J. Jiménez pers. obs.).

In the coastal range of Los Ríos Region, Darwin’s Foxes have been primarily recorded in old-growth and secondary evergreen forests, though they were also detected in unmanaged Eucalyptus spp. plantations (Farías et al. 2014). Foxes are apparently more frequent in the southern area of the Valdivian Coastal Reserve, an area that was less impacted by forest substitution and that have lower human (and dog) densities than the northern area (E. A. Silva-Rodríguez et al. pers. obs.). Finally, records near the Llanquihue Lake were in a highly fragmented forest with intensive dairy farms having large pastures with linear strips of degraded Valdivian forest along streams (J. Jiménez pers. obs.).

In Chiloé, foxes use a variety of habitats. A study conducted in Chiloé, found that foxes used second-growth forests and scrublands according to availability, old-growth forest less than expected according to availability and that the use of dunes varied between individuals (Jiménez 2007). The consumption of crustaceans and direct observation provides evidence that sandy beaches are also used by this species (Elgueta et al. 2007, Jiménez 2007). In the north-east of the island, where the forest is fragmented, Darwin’s Fox occur in the larger forest fragments (Farías and Jaksic 2011). Home ranges vary between 103 and 488 ha (Jiménez 2007).

Threats Information

Domestic dogs and associated diseases are likely the main threats for Darwin’s Foxes (Jiménez and McMahon 2004). Dogs are a common problem in Chilean protected areas, including each of those where the Darwin’s Fox is present. Domestic dogs would represent a risk for foxes through intra-guild killing, as well as through disease transmission (Jiménez and McMahon 2004, Cabello et al. 2013a,b). The death of Darwin’s Foxes due to dog attacks has been reported both on the mainland (D’Elia et al. 2013) and in Chiloé (Espinosa 2011, J. Jiménez pers. obs.). Moreira-Arce et al. (2015a) found a negative correlation between the areas used by dogs and foxes in Nahuelbuta. Accordingly, in Chiloé Island, Darwin’s Foxes are rare or absent from old-growth forests frequently visited by dogs, while they are frequently recorded at camera traps in scrublands when dogs are absent (A. Farías pers. obs.), suggesting spatial displacement. It is important to note that the dog problem that affects Darwin’s Foxes, is caused in most, if not all, cases by poorly managed free-ranging dogs and not feral dogs (D. Moreira pers. obs., E.A. Silva-Rodríguez et al. pers. obs.).

The risk of disease spillover from dogs (mainly Canine Distemper Virus, CDV) is considered a major threat for Darwin’s Fox populations (e.g., Jiménez and McMahon 2004, Silva-Rodríguez et al. 2015). Exposure of dogs to CDV has been shown in the proximity of Nahuelbuta National Park (Acosta-Jamett et al. 2015b) and Valdivian Coastal Reserve-Alerce Costero National Park (Sepúlveda et al. 2014). Furthermore, exposure to CDV has been reported for invasive American minks (Neovison vison) in areas were the Darwin’s Fox is present (Sepúlveda et al. 2014), as well as for Chilla (Lycalopex griseus) and Culpeo (Lycalopex culpaeus) in other regions (Acosta-Jamett et al. 2015a). Additionally, Jiménez et al. (2012) reported the death of three radio-collared foxes in Chiloé in sympatry with free-ranging dogs, suggesting that mortality could have been caused by CDV, although conclusive evidence was not available. CDV epizootics in canids have been reported worldwide (e.g., Goller et al. 2010, Di Sabatino et al. 2014), and CDV was implicated in a major decline in the population of the Island Fox (Urocyon littoralis) in Santa Catalina Island (Timm et al. 2009). In South America, Megid et al. (2009, 2010) reported CDV-related mortalities in wild canids in Brazil, and in Chile, Moreira and Stutzin (2005) reported the death of 27 Chilla and Culpeo foxes due to CDV in Coquimbo Region. The lack of conclusive evidence of declines due to CDV in the Darwin’s Fox may be well explained by lack of information, rather than by the absence of outbreaks.

Darwin’s Foxes can also be subject to human-caused mortality. According to J. Jiménez (pers. obs.) and Espinosa (2011), local people in Chiloé reported killing foxes because they attack domestic animals and to obtain their fur. Foxes rescued from traps as well as captured and translocated after predation on poultry have also been reported in Chiloé (J. Cabello pers. obs.). Stowhas (2012) also indicated that local people reported killing foxes (undetermined species) in an area that included the surroundings of Oncol Park, Alerce Costero National Park, and Valdivian Coastal Reserve, as a response to predation on poultry. In Nahuelbuta range, foxes (without distinguishing to the level of species) are often considered as problem animals (Sánchez et al. 2014). However, Darwin’s Fox is not commonly persecuted or killed by local people (but see McMahon et al. 1999) and its conservation would show a high social support (D. Moreira pers. obs.).

Forest loss is an important threat. The highest rates of forest loss occur in the coastal range of the Araucanía Region, where Nahuelbuta is located. There, the annual loss rate observed for the 1999-2008 period reached 4.8%, the second highest reported for Chilean temperate forest (Miranda et al. 2015). For the Valdivian Coastal Range, the net forest loss between 1985 and 2011 was 5.1% (and the gross loss reached 30%), but the loss rate was higher for the 1985-1999 period than for the 1999-2011 period (Zamorano-Elgueta et al. 2015). In northern Chiloé and Maullín, the annual rates of forest loss was close to 1% (1985-2007), although in the case of Chiloé this rate rose to 1.4% for the 1999-2007 period (Echeverría et al. 2012). Both in the Araucanía and Valdivian cases, cleared native forest was frequently converted to forestry plantations (Miranda et al. 2015, Zamorano-Elgueta et al. 2015). Although Darwin’s Fox has been recorded in plantations (Farías et al. 2014, J. Jiménez pers. obs.), evidence from the population in Nahuelbuta shows that foxes select for native forest (Moreira-Arce et al. 2015a). However, if managed through an increase of native understory cover, commercial plantations may provide complementary habitats and food resources for this species (Moreira-Arce et al. 2015b). Human-induced fires are an always-latent threat, especially for the Nahuelbuta range (D. Moreira pers. obs.). On the other hand, deforestation may favour other (larger sized) fox species (i.e. Lycalopex griseus and L. culpaeus), better adapted to open areas (e.g., Silva-Rodríguez et al. 2010), which can displace Darwin’s Foxes (Jiménez et al. 1991). The indirect effects of changes in land cover through alteration of interaction webs are still insufficiently known.

Indirect threats that need to be considered include the construction of bridges, highways and roads. Of major concern is the projected construction of the bridge connecting Chiloé to the mainland. This bridge, if barriers are not implemented, may facilitate the invasion of the island by other species such as congeneric foxes and Pumas (Puma concolor), with unknown, but potentially serious consequences for these populations. Road construction and improvement is an additional concern, given that they facilitate dog (Moreira-Arce et al. 2015a, Sepúlveda et al. 2015) and human movement, and can lead to land cover change (Wilson et al. 2005). Existing roads, as well as the construction of new roads and/or the improvement of existing public roads, is a concern for Nahuelbuta (Sánchez et al. 2014), the Valdivian Coastal Range (Silva-Rodríguez et al. 2015) and for Chiloé (J. Cabello pers. obs.).

Other threats that need to be taken into account include the translocation of rescued and problem animals (J. Cabello pers. obs.) and illegal tenure of foxes as pets (J. Jiménez pers. obs.).

Use and Trade Information

There is no commercial use of this species. However, some animals have been illegally kept in captivity as pets (Jiménez and McMahon 2004), and there is some limited off-take for fur (Espinosa 2011).

Conservation Actions Information

Legislation
Included on CITES - Appendix II. Protected by Chilean law since 1929 (Iriarte and Jaksic 1986). Darwin’s Fox is listed as endangered in Chile (DS 151/2007 MINSEGPRES). Since 2012, the Ministry of the Environment is working in the elaboration of the Recovery, Conservation and Management plan for the species (RECOGE for its Spanish acronym), but this plan is not in effect yet.

Presence in protected areas
The Darwin’s Fox occurs in the following public protected areas: Nahuelbuta National Park (Araucanía Administrative Region), Alerce Costero National Park (Los Ríos Administrative Region), and Chiloé National Park (Los Lagos Administrative Region). In addition, the species is found in the following private protected areas: Caramávida Reserve (Biobío Administrative Region), Oncol Park and Valdivian Coastal Reserve (Los Ríos Administrative Region), and Tantauco, Ahuenco and Tepuhueico Parks (Los Lagos Administrative Region). Some of these protected areas are targeting the species through monitoring, supporting research or attempting to address the dog problem (e.g., Sánchez et al. 2014, Silva-Rodríguez et al. 2015). The Darwin’s Fox is one of the conservation targets (Darwin’s Fox, guigna and pudu) of the Valdivian Coastal Reserve (Silva-Rodríguez et al. 2015). Following the criteria by Simonetti and Mella (1997), and the densities reported by Jiménez (2007), it is possible to assume that good quality areas of around 550 km²in size could sustain ~500 individuals (Silva-Rodríguez et al. 2015). Tantauco Park in Chiloé, and the area protected by the Valdivian Coastal Reserve and Alerce Costero National Park as a whole, are the only protected areas that meet this criterion, although this does not guarantee the existence of such a number of foxes, as they appear to be scarcer in the Valdivian population (E. A. Silva-Rodríguez and A. Farías, pers. obs.), and the density of foxes in Ahuenco could be much higher than in other areas (Jiménez 2007).

Species-based measures
Vaccination of dogs against CDV has been conducted around some of the above-mentioned protected areas with the aim of preventing disease outbreaks that could affect Darwin’s Foxes (e.g., Sánchez et al. 2014, Silva-Rodríguez et al. pers. obs.). Current efforts to understand problems related to disease and its management in this species include the project ”Saving Darwin’s Fox: A Conservation Medicine Approach” led by Buin Zoo and several local organizations including among them Chiloé Silvestre and Parque Tantauco, as well as several universities.

Environmental education efforts are being conducted by several stakeholders. These include efforts by the Ministry of Environment, CONAF (Chile’s Forest Service), as well as private organizations such as the Committee for the Rescue of Nahuelbuta, Tantauco and The Nature Conservancy.

Presence in captivity
Currently, the only known captive Darwin’s Foxes are kept by Fauna Andina near Villarrica, where successful reproduction has been achieved in two consecutive years. These animals have been rescued from dog attacks and illegal ownership from Chiloé (F. Vidal pers. comm.).

Gaps in knowledge
Most known populations are currently being studied by researchers from multiple institutions. Key topics under study include genetics (J. Cabello pers. obs.), disease (E. Hidalgo pers. comm.), occupancy and habitat use (Silva-Rodríguez et al. pers. obs.). The later topic still deserves clarification regarding (1) the presence of the species between the Bueno and Maullín rivers (i.e. coastal mountain range of Osorno Province), (2) its potential presence in the Andes and lowlands between the Andes and the Coastal Range, and (3) under-explored areas in continental Chiloé. Furthermore, accurate information is needed regarding the abundance of the species in each of these populations.

Key issues that need to be addressed include the management of domestic dogs. Irresponsible ownership is the rule rather than the exception in Chile. Despite long legislative discussion, no serious solution is in place for this problem. Effective enforcement of responsible ownership is absolutely necessary to address this problem. Recently CONAF passed some rules that limit the entrance of dogs to protected areas (CONAF 2015), but these measures need to be supported by a coherent legislation.

The adequate management of exotic plantations is an important priority. Recent studies suggest that several forest species can use forest plantations if they have dense native understory (Simonetti et al. 2013). Thus, leaving understory in exotic tree plantations may be key to maintain connectivity in Darwin’s Fox populations, especially in Nahuelbuta (Moreira-Arce et al. 2016). The challenge is to implement these recommendations.