maned wolf - © Rogerio Cunha
Maned Wolf Working Group - The Maned Wolf Working Group is an organization within the IUCN’s Canid Specialist Group created as a tool to improve the communication among the countries where the maned wolf occurs. It is composed of researchers from several areas of interest aiming to work in collaboration to discuss and implement strategies for a better assessment of information and reduction of impacts related to the largest South American canid species.Projects
The current population of Maned Wolves is estimated at approximately 17,000 mature individuals (≥ 2 years of age), with the majority of the population (>90%) in Brazil. In the last decade or so, the species’ main habitats in Brazil have been subject to intense deforestation. A population viability model for Brazil generated using real and predicted deforestation rates over 15 years (three generations) resulted in an estimated reduction of ~20% in the metapopulation (based on current estimates of habitat loss ranging from 1.0 to 1.5% per year). If deforestation reaches the maximum estimated rate of loss (2% per year), then simulation suggests a national population reduction of 56% at the end of 100 years (Paula et al. 2008, Paula and Desbiez 2014). In addition to the estimated population reduction from deforestation, the species is also subject to other threats, including road kills, direct persecution by humans, and disease due to contact with domestic animals (Paula and Desbiez 2014). In other range countries (Argentina, Paraguay and Bolivia), the species’ status is even more precarious with small isolated populations and declining numbers due to the low quality of habitat and hunting. The Maned Wolf does not meet the thresholds for listing under criteria B, C or D, but taking into account the combined impacts of habitat loss, persecution and disease, it approximates the thresholds for listing under A3, and is therefore assessed as Near Threatened. The species’ situation is considered to be of major concern due to the various threats acting throughout its entire range and should be regularly re-evaluated.
The Maned Wolf inhabits lowland grasslands and scrublands of central South America, south of the mouth of the Parnaiba River in northeastern Brazil, throughout eastern Paraguay east of the Rio Paraguay, extending into north/northeast Rio Grande do Sul State in Brazil, south to Santa Fe and Entre Rios provinces in Argentina and west to the Pampas del Heath in Peru (Queirolo et al. 2011, Williams et al. 2012).
In Brazil, the range is limited by the Amazon forest in the north/northwest and by the arid Caatinga in the northeast (Queirolo et al. 2011). In the last five years, the Maned Wolf has been recorded in areas where no records (> 50 years) previously existed, specifically in areas where habitat degradation and conversion are occurring. In the “Amazonian arc of deforestation”, south of Amazonas and south/east of Para states, the species has been increasingly registered in areas that were converted from forests into pastures and agricultural fields (R. Paula pers. comm. 2015). The same is true, but to a greater degree, in southeastern Brazil where the Atlantic Forest biome has been deforested and the Cerrado has been degraded (Queirolo et al. 2011). Although these records might suggest an expansion of the species’ distribution range, records are scattered and populations may not be stable. In Argentina, the species is present in the northern and central region of the country (Queirolo et al. 2011) but a range contraction has occurred in the south with most recent records in the provinces of Chaco, eastern Santiago del Estero, northeastern Córdoba, northern Santa Fe, northern Entre Ríos, Corrientes, and southern Misiones (Queirolo et al. 2011). The range across eastern Paraguay is considered widespread, but discontinuous, with no large concentration in any single area (Cartes et al. 2014). The Maned Wolf is distributed across the savannas of Bolivia; however, all detailed information for this country is limited to a single park in the department of Santa Cruz (Emmons 2014). The species historically ranged into northern Uruguay, but to date there have been only sporadic and unconfirmed occurrences in the north-east (Queirolo et al. 2011) since the last confirmed record in 1990 (Mones and Olazarri 1990).
Two recent evaluations of Maned Wolf distribution have provided an update on the full extent of the range (Quierolo et al. 2011), including range shifts within Brazil (Paula et al. 2013). These studies recorded that the Maned Wolf distribution covers nearly five million km2 with ~72% of the range located in Brazil, which corresponds to an increase in the total area reported 30 years ago (3,414,169 km2) by Dietz (1984). This increase in the Maned Wolf distribution is likely due to both genuine change (the species’ expansion into new regions) as well as non-genuine change (mostly new or additional records from the field).
More recently, to seek greater precision concerning the distribution range of the species in Brazil, potential distribution and probability of presence were modelled with Maxent, a software using maximum entropy algorithms (R. Paula and E. Ferraz pers. comm. 2015). All Brazilian biomes, with the exception of the Amazon and Caatinga, neither of which are suitable for the Maned Wolf, were modelled using >1,000 presence points collected in the last 10 years combined with several variables (including topographic, bioclimatic, geophysical and anthropogenic) at a resolution of one km2. The results indicate that the potential distribution area for Maned Wolves in Brazil is 2,815,061 km2. The majority (70%) of this area represents areas with <25% probability of presence and those areas are considered unsuitable for the Maned Wolf occupancy. In addition, the highly suitable area (i.e., >75% probability of presence) accounts for only 0.4% of the total of the species’ distribution area within Brazil. These declines in both total area and overlap with lower probabilities of presence reflect an increase in deforestation rates in the Cerrado over the last 20 years. While the species has been documented in other biomes, the model suggests a retraction of their distribution within the Cerrado due to the ongoing conversion of intact habitat to areas with agriculture and pastures; therefore, while there is evidence that Maned Wolves can persist in mosaics of natural and disturbed areas, extensive monocultures and exotic pasturelands have been indicated as unsuitable areas.
A Population and Habitat Viability Assessment (PHVA) workshop held in 2005 estimated the total population (newborn pups, juveniles and adults) of Maned Wolves at ~23,600 animals, including 21,746 in Brazil, 830 in Paraguay, and 660 in Argentina (Paula et al. 2008). If only mature individuals (≥ 2 years of age) are considered, the population size is estimated at 17,000 animals, including 15,849 in Brazil, 613 in Paraguay, and 487 in Argentina (Paula et al. 2008). Numbers in Bolivia are unlikely to exceed 1,000 animals. Numbers in Pampas del Heath, Peru are less than 40 individuals, declining, and likely geographically isolated from the adjacent Bolivian population (Williams et al. 2012). The population estimates from the PHVA workshop were generated using Vortex simulation computer models and so do require some caution (Paula et al. 2008). Even though the species has been supposedly expanding into new areas in Brazil, the species’ overall range has contracted in the Brazilian Cerrado (its typical habitat) and in other countries. In addition, over the last 10 years some of the areas previously defined as the most suitable in Brazil have suffered from habitat degradation, suggesting that these prior published estimates may now be considered high.
To account for the effects of habitat loss, one of the main threats to Maned Wolf, on persistence, simulations of the effects of habitat loss using detailed data on deforestation rates in Brazil were performed (and measured as permanent reduction in K or carrying capacity). This was modelled as a linear decrease (1.5% / annum) in carrying capacity over one generation or five years, which effectively reduced the maximum size a population could attain. The simulation model showed that small populations were affected more than large populations, with populations <25 individuals showing negative growth rates due to their vulnerability to stochastic processes. Populations with ≤25 individuals declined with a high probability of extinction within 100 years; however, populations of 50-100 individuals persisted, albeit with low levels of genetic diversity. Therefore, several hundred wolves may be needed to maintain a long-term, viable population depending upon the severity of threats, management goals, and acceptable levels of risk for wildlife managers.
In the last 10 years, the main habitats of Maned Wolf in Brazil have been subject to intense deforestation. For the current assessment, a population viability model was generated using recent observed deforestation rates, ranging from 1.0 to 1.5% per year over 15 years (three generations). These results suggested a 20% reduction in the metapopulation based on these rates of loss. If deforestation rates reach a loss of 2% per year, the simulation suggests a 56% reduction in the Brazilian population in 100 years (Paula et al. 2008, Paula and Desbiez 2014). The areas of supposed distribution expansion were not accounted for in this simulation since they represent edge areas for the distribution range and because from what is known presently these areas do not seem to hold stable and resident populations of the species.
Maned Wolves are found at low densities throughout the range. Even in Brazilian protected areas, population densities range from 0.01 to 0.05 animals/km2 (Silveira 1999, Rodrigues 2002). The highest density reported is 0.08 individuals/km2 in Serra da Canastra, Minas Gerais, Brazil (Paula et al. 2013). In Argentina, information about wild populations is scarce and the northern population is thought to be declining (Soler and Carenton 2008). Despite the lack of information on population densities across it range, high food availability may potentially support higher population densities (Amboni 2007, Azevedo 2008).
In general, Maned Wolves inhabit open habitat types favouring grasslands, shrub habitats, woodland with an open canopy (cerrado), mixed forest/grassland, and wet fields (which may be seasonally flooded). Rocky fields associated with open grasslands in higher altitudes (1,000-2,000 m asl) can be an important habitat for the species in some areas (Coelho et al. 2008, R. Paula pers. obs.). In central Brazil, similar to Bestelmeyer (2000), who found Maned Wolves prefer areas with low to medium shrub density, Vynne et al. (2011) found they avoided areas where the closed canopy was ≥30%. Coelho et al. (2008) found the Maned Wolf strongly avoided the forested areas that border the Cerrado and Atlantic forest ecoregions. In northeastern Argentina, south/southeastern Brazil, and southeastern Paraguay, Maned Wolves have been recorded in the exotic eucalyptus, pine, soybean and sunflower plantations (Orozco et al. 2009, Soler 2009, A.J. Giordano pers. comm. 2015, R. Paula pers. obs.) and in remnants of Atlantic forest (Chiarello 2000, A.J. Giordano pers. comm. 2015). Also, the presence of Maned Wolves in populated rural and urban areas was also documented in the last ten years in Santa Fe, Corrientes, Chaco and Santiago de Estero provinces in Argentina (Pautasso et al. 2009, Orozco et al. 2013a). In addition while Maned Wolves preferred open, natural grasslands, they were as likely to use low-standing croplands within five kilometres due to the high density of rodents (Vynne et al. 2011). While Queirolo et al. (2011) proposed that Maned Wolves are expanding their former range in Brazil to include areas converted from inhospitable primary or thick secondary forest into open areas for grassland, agriculture and livestock. Muir and Emmons (2012) failed to find evidence of Maned Wolves expanding into agricultural areas in Bolivia. In Paraguay, preliminary studies with camera traps suggest that sustainable cattle-ranching was compatible with high Maned Wolf activity (A.J. Giordano pers. comm. 2015). Vynne (2010) suggests the foraging benefits of agricultural areas are negated when the crops become tall, homogenous, monoculture crops (e.g., sugarcane). Vynne et al. (2014) found that Maned Wolves may be tolerant of these habitat conversions as long as there are sufficient remnant vegetation patches for den sites, food, water and resting, including gallery forests (Dietz 1984), cerrado and marshy areas near rivers (Bestelmeyer 2000, F. Rodrigues pers. comm. 2015).
The omnivorous diet of the Maned Wolf includes a wide variety of plant material and animal matter, including fruits, arthropods and small- to medium-sized vertebrates (Dietz 1984, Carvalho and Vasconcellos 1995, Motta-Júnior et al. 1996, Azevedo and Gastal 1997, Motta-Júnior 1997, Rodrigues et al. 1998, Jácomo 1999, Santos 1999, Silveira 1999, Juarez and Marinho-Filho 2002, Amboni 2007). Although the frequency of plant and animal items found in faecal samples is approximately equal, the biomass of animal items is usually greater than that of plant items (Motta-Júnior et al. 1996, Santos 1999, Motta-Junior et al. 2014). The relative importance of specific food items may vary depending on location and season (Bueno and Motta-Júnior 2006, Amboni 2007). In areas of high food availability, the degree of overlap of home ranges increases and can reach levels of 92% between female-female and 100% for male-female (couple; Amboni 2007, Azevedo 2008, R. Paula pers. obs.).
While historically Maned Wolves were considered to be crepuscular-nocturnal in their activities, recent observations in Bolivia and Brazil reveal that their activity is actually variable or cathermeral, with activity patterns changing according to daily temperatures and the season (dry or wet; Emmons 2012). In Santa Cruz, Bolivia, Emmons (2012) found Maned Wolves tend to forage for longer distances when temperatures are cooler (between 21-28°C) and show considerable decreases in activity levels when temperatures increase (>28°C). In addition, while the Maned Wolf is strictly nocturnal during the dry season, it varies in its temporal activity pattern during the wet season (Emmons 2012). These patterns shift some in southeastern Brazil, an area defined by higher humidity levels, abundant permanent water sources in the form of rivers, well-defined seasons reflecting extreme temperature differences, and shifts in the seasonal food availability. While the activity pattern of Maned Wolves in Brazil is cathemeral and affected by overall temperature and seasonality, the high degree of daily variation in minimum and maximum temperature in a season means that there is additional variation in the daily pattern each season (R. Paula pers. obs.). For example, during the dry season when temperatures drop to 5°C during the night, the species is more diurnal having higher activity during the day when temperatures are likely to be warmer. In contrast during the wet season activity is typically nocturnal, except after extended periods of rain when the species can be active during the middle of the day.
The home range of Maned Wolves is variable, ranging from 20-115 km2 (fixed kernel, 95%). Despite considerable variation ranges average between 50-80 km2 (fixed kernel, 95%; Rodrigues 2002, Coelho et al. 2008, Azevedo 2008, Emmons 2012) and about 30 km2 in agricultural landscape of northern Argentina (L. Soler pers. comm. 2015). Food availability and habitat integrity have been linked to variation in home range size (Amboni 2007, Azevedo 2008, R. Paula pers. obs.). Sharing of home ranges has been noted in Brazil and Bolivia (Azevedo 2008, Emmons 2012). While home range overlap can be found during the breeding season, it is possible throughout the year in areas with high food availability. In these areas, the greatest sharing of home ranges is between females followed by male-female pairs with very little sharing tolerance noted among males (Azevedo 2008).
In northern Argentina the Maned Wolf shows a preference for open grassland habitats and also utilizing human disturbed areas such as cattle ranches (Soler and Carenton 2008). Direct competition with other carnivores has not been observed; however, scat analyses reveal that Maned Wolves, Crab-eating Fox (Cerdocyon thous) and Pampas Fox (Lycalopex gymnocercus) and Crab-eating Raccoon (Procyon cancrivorus) consume many of the same prey species (Soler and Carenton 2008).
Paula et al. (2008) calculated a generation time of 5.3 years in Vortex (using the exponential growth rate as another variable to account to the net reproductive rate calculations, which is the age-specific survival multiplied by fecundity over all age classes; see Lacy et al. 2015 for further details). Using the formula Sum (x lx mx)/Sum (lx mx) where lx represents the survivourship over x years and mx the maternity over x years, Paula and Desbiez (2014) calculated a generation length of 7 years. No differences on population reduction were observed when using the two different generation times.
The four main threats affecting Maned Wolf populations throughout their distribution range are: habitat loss and alteration, especially due to conversion to crop fields and pasturelands; human persecution due to livestock losses and cultural beliefs; increasing vehicular traffic in highways resulting in road kills; and pathogens contracted from domestic animals due to increased contact in disturbed environments (Paula et al. 2008, 2013, Emmons 2012, Orozco et al. 2013a).
The intensive conversion of native habitat for agriculture results in loss of optimal habitat and creation of areas often subject to desertification. The fragmentation of highly suitable habitat causes isolation of subpopulations and often results in the remaining intact landscape become intersected by high speed roads. Many Maned Wolves are killed on roadways throughout its range. In central Brazil, road kills are a threat of major concern potentially leading to local extinction of small, isolated populations as estimates range from four to 10 individuals killed/year in some regions (Paula and Gambarini 2013, Rodrigues et al. 2014). Similar impact of vehicular collisions was detected in marginal populations from Argentina where 21 Maned Wolves were reported dead along National Route 34, concentrated between 2000 and 2005 (Orozco et al. 2013a). The same negative effect is potentially true in the humid Chaco of Paraguay where increased traffic on the Trans-Chaco highway leads to numerous road kills each year (A.J. Giordano pers. comm. 2015). Extreme climatic conditions such as uncontrolled fires and droughts are likely to exacerbate the scarcity of living resources and consequently the loss on roadways, as Maned Wolves are forced to travel farther for food and water (Pautasso et al. 2009, Orozco et al. 2013a); the latter is especially important during periods when females are lactating (Emmons 2014).
Direct interactions with humans also pose a threat to the species. Conflicts with people, road mortality, the potential for infectious diseases spread by domestic dogs and direct persecution resulting from widely held superstitions and beliefs, are the primary threats facing Maned Wolves (Songsasen and Rodden 2010). In some areas of Argentina, Maned Wolves are persecuted with hunting, trapping, and shooting due to a mix of long-standing cultural beliefs, general ignorance of the species, and trophy hunting (Orozco et al. 2009, Orozco et al. 2013a, Soler 2014). In southeastern Santiago del Estero (Argentina), 30 Maned Wolves were reported sold to game ranches in a 10-year period (Orozco et al. 2013a). In Brazil and Paraguay, this targeted persecution of Maned Wolves extends beyond the traditional and natural medicine needs to include the low public tolerance of poultry depredation, for which Maned Wolves are constantly blamed (Paula et al. 2013, Cartes et al. 2014, A.J. Giordano pers. comm. 2015). In some areas this hunting pressure is so high it is having a significant negative effect on local Maned Wolf numbers (Paula et al. 2013). While illegal trade is not common, Orozco et al. (2009) found it was widespread in Argentina, and even included the sale of young animals or pups to private zoos and collections. Of the Maned Wolves kept in captivity in Argentina during the last five years 68% were wild born and came from/were victims of illegal trade, road collisions or were orphaned after their mother was killed (P. Gonzalez Ciccia pers. comm. 2015).
Domestic dogs pose a serious threat to Maned Wolves on several levels, as often times domestic dogs accompany humans into the field for recreation and hunting. In addition, both Maned Wolves and dogs overlap in their use of habitat that has been converted to agriculture and pasture. Dogs are known to pursue Maned Wolves, which often results in the killing of the animal (Soler et al. 2005, Pautasso et al. 2009, Orozco et al. 2013a, Soler 2014, A.J. Giordano pers. comm. 2015). In a study carried out in Argentina, 26% of sightings by local villagers involved close contact between Maned Wolves and domestic dogs (Orozco et al. 2013a). Dogs are also a source of infectious diseases and parasites. However the epidemiological effects remain unclear for Maned Wolf conservation. Rural domestic dog populations in Argentina had very high seroprevalence for Neospora caninum, canine coronavirus, canine adenovirus, Dirofilara immitis, canine distemper virus, Toxoplasma gondii, and L. interrogans spp. In the same area, all of these agents (except N. caninum, Toxoplasma gondii and CCV) were serologically positive in local Maned Wolves (Orozco et al. 2013a). In a Bolivian population, Maned Wolves were serologically positive for two domestic dog pathogens (morbillivirus and parvovirus) that can cause pup mortality and high levels of potentially fatal (Dirofilara immitis) and debilitating (Dioctophyme renale) parasites were detected (Deem and Emmons 2005, Bronson et al. 2008, Deem et al. 2012, Emmons 2014). In Brazil, Maned Wolves were serologically positive for several dog-related infectious diseases including parvovirus, canine distemper virus, coronavirus, and leishmaniosis (Paula et al. 2014). These data from Bolivia, Brazil and Argentina suggest that other wild populations are at risk in areas where domestic dogs are present (May Jr and Felippe 2014). The frequent use of dogs for herding and hunting, along with their frequent foraging in natural habitats, could favour direct or indirect transmission of multiple pathogens (Orozco et al. 2013a).
There is no commercial use. Indications are that the use of Maned Wolf parts for medicinal purposes does not involve any sort of large-scale commercial transactions and is confined to native folk medicine (Soler et al. 2008, Orozco et al. 2009, Emmons 2012, Paula and Gambarini 2013).
It is included on CITES Appendix II. Maned Wolves are protected by law in many parts of their range, but enforcement is frequently problematic. This species is classified as Endangered in Argentina (Ojeda et al. 2012) and declared a Provincial Natural Monument in select areas, including Santa Fe, Corrientes, and Chaco (Soler 2014). It is classified as Vulnerable in Brazil (Paula et al. 2013). Hunting is prohibited in Brazil, Paraguay, Bolivia and in Argentina. The species is included in the United States Endangered Species list.
Presence in protected areas
This species occurs in many protected areas in Argentina, Bolivia, Brazil, Paraguay and Peru
Occurrence in captivity
As of January 2012, 150 institutions held a total of 394 Maned Wolves (182 males, 211 females, one unknown) in captivity (Holland 2014).
In Brazil, conservation actions to reverse population decline have focused on addressing the issues associated with the human dimension. Raising public awareness and using proactive methods to prevent conflict are among the main tools used in increasing tolerance towards the species. In addition, campaigns to vaccinate domestic dogs in areas that border or overlap with Maned Wolf populations have been ongoing for several years (Paula et al. 2014). New proposals to reduce the high number of road kills in southeast Brazil have been discussed at a political level. The 2005 Population and Habitat Viability Assessment workshop for Maned Wolves generated an Action Plan aimed at addressing the five main themes that effect the long-term conservation of the species across its distribution: 1) threats and habitat management; 2) distribution and status; 3) environmental education, social aspects, and economic alternatives; 4) ex-situ conservation; and 5) population dynamics and modelling (Paula et al. 2008). Each of these themes address gaps in knowledge for the species or specific problems associated with the species survival. Each theme was broken into multiple goals with specific actions set to address the associated problems, names of personnel responsible for seeing the action is completed, timeline for when these actions should be completed, associated costs, potential obstacles, and expected outcome defined (Paula et al. 2008). As a follow up to this workshop, Brazil and Argentina used information on recent and ongoing changes in the species’ status and threats to modify the international Action plan and generate specific National Action Plans that could help direct local efforts in Maned Wolf conservation. In 2014, the Brazilian government officially recognized the technical advisory group (originally formed in 2010) aimed at assisting the government on implementing the strategies developed in the National Action Plan. A Maned Wolf working group has also been implemented in continental level under the coordination of the IUCN SSC Canid Specialist Group, with an aim to ensure long-term coordination among researchers across the Maned Wolves distribution and work together to share strategies directed at reversing population decline.
In Argentina, the GAAG (Grupo Argentino Aguará Guazú or Maned Wolf Argentine Group) was founded as a national strategy to develop, manage, execute, and monitor the Action Plan for the Maned Wolf’s conservation in Argentina. The group comprises 16 institutional members, which includes provincial and national government agencies, zoos, NGOs and research groups from universities and museums. Between 2002 and 2011, GAAG carried out 10 regional workshops aimed at: 1) mapping threats for Maned Wolf in natural habitats; 2) prioritizing conflicts in the wild and problems in captivity; 3) prioritizing strategies and actions for its ex situ and in situ conservation; 4) developing recommendations for conservation in the wild and management in captivity; 5) developing efficient education strategies for Maned Wolf conservation both in situ and ex situ, and 6) validating methodologies and strategies for conservation education. Since 2005, five species-directed projects have been developed and include work in five of the eight provinces in the Maned Wolf’s distribution (Orozco et al. 2013b). Extensive surveys of farmers and ranchers have provided valuable information about the distribution of the species and also about people's attitudes towards Maned Wolves (Songsasen and Rodden 2010). Ongoing education programs are aimed at changing negative perceptions of this wild carnivore (Soler 2008, Orozco et al. 2013b).