The decline of jaguars Panthera onca in the Argentine Chaco

Abstract

We assessed the distribution and status of jaguar Panthera onca in the Argentine Chaco, one of the least known areas within its range. Current jaguar distribution in the Chaco encompasses parts of central and western Formosa, western Chaco, eastern Salta and north-eastern Santiago del Estero Provinces. Jaguar range was reduced following colonization of the semiarid Chaco even though there has been little deforestation. Jaguars have not been observed over the last 15 years in areas where colonization occurred more than 35 years ago, probably reflecting hunting pressure. Livestock predation is lower now than when the area was first settled in the 1920s. This may indicate low jaguar densities as the livestock management system has not changed. Local people, however, continue to hunt jaguars with the intention of exterminating them. Education, enforcing jaguar hunting laws, increasing control of poaching in protected areas, and creating more protected areas may be the most efficient strategies to preserve the jaguar population of the Argentine Chaco.

Modeling the effects of deforestation on the connectivity of jaguar Panthera onca populations at the southern extent of the species’ range

“…The use by jaguars of defined corridors between the Baritú-Calilegua, Chaco and Gran Chaco JCUs has, however, been demonstrated to be extremely limited in the Bolivian Yungas and the Bolivian and Argentine Chaco (Thompson & Martinez 2015). This supports the validity of our approach to cost-limit linkages between JCUs, which is further reinforced by the critically endangered status of the jaguar population in the Argentine Chaco (Altrichter et al 2006, Quiroga et al 2014). Focusing upon the cost-limited linkage network demonstrates how ongoing land use change in eastern Bolivia has resulted in the loss of direct connectivity between the southwest Amazon and Chiquitano forest (Noel Kempff Mercado JCU) and the Bolivian and Paraguayan Chaco (Gran Chaco JCU), in addition to the isolation of the southern and easternmost JCUs.…”

“…This interpretation is supported by the distribution and population genetics of jaguars in these systems (Altrichter et al 2006, Haag et al 2010. Current density within the least-cost linkage networks between Jaguar Conservation Units (JCUs) for 2000 and 2014 displayed for 25 km cost-weighted distance from the least-cost paths.…”

Impact of deforestation on habitat connectivity thresholds for large carnivores in tropical forests

“…Thresholds remain controversial, but there is evidence in theoretical and empirical studies that habitat loss has a significant effect on species occurrence within landscapes (Martensen et al 2012;Johnson 2013). The existence of a threshold zone in structural connectivity may imply changes in natural vegetation dynamics, decreased availability of food resources, increased contact with humans and potentially human-jaguar conflicts (Altrichter et al 2006;Rumiz et al 2012;Young et al 2014). Although jaguars may move across fragmented landscapes, they tend not to use small patches (<200 ha) as they prefer natural vegetation patches > 2000 ha (Ramirez-Reyes et al 2016).…”

“…The impact of agriculture and the recent surge of gold mining in the Amazon (Tobler et al 2013) are likely to exacerbate the reduction in vegetation extent with long-term impacts on jaguar population. This may be compounded by hunting and other potential humanjaguar conflicts (Altrichter et al 2006;Rumiz et al 2012). The effects of deforestation and loss of natural habitat are affecting a large number of species around the world.…”

Guest editorial

“…Threatened large mammals are rarely loved by the people living with them. Global conservation flagships can be local pests, and if livestock predation and crop raiding are not addressed, such species are persecuted (Altrichter et al, 2006). Fortunately a great deal of conservation science and practice is being brought to bear to find solutions to offset the costs borne by poor rural communities.…”