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Recent land‐use changes and the expansion of an exotic potential prey: a possible redemption for A tlantic forest jaguars?

2015; Wiley; Volume: 19; Issue: 3 Linguagem: Inglês

10.1111/acv.12221

1469-1795

Luciano M. Verdade, Francisço Palomares, Hilton Thadeu Zarate do Couto, Jefferson Lordello Polizel,

Animal Disease Management and Epidemiology

Jaguars Panthera onca are absent from approximately 70% of the remaining Brazilian Atlantic Forest due to a combination of habitat loss and degradation, poaching and high hunting pressure on their prey (Azevedo & Conforti, 2008; Galetti et al., 2013). This contrasts with North American and European large terrestrial predators that are recovering their historical abundance levels, colonizing even environments that are shaped by humans (Morrel, 2013; Chapron et al., 2014). Population supplementation and reintroduction programs, linked with hunting control, are proposed as management actions to reverse the jaguar's fate (Galetti et al., 2013); however, a combination of agricultural land-use change and the introduction of an invasive exotic species – the wild boar Sus scrofa – might, paradoxically, have more of a positive effect. The state of São Paulo (Southeastern Brazil) hosts some of the largest protected remnants of Atlantic Forest, but in most of them jaguars are locally extinct. In the past two decades, large areas of relatively unproductive pasturelands, used for livestock grazing in this state, have been replaced by either sugarcane or Eucalyptus plantations. Such land-use change is directly impacting biodiversity (Verdade et al., 2012), but might benefit jaguars. The background of workers involved in these agro-industrial activities is changing from local residents to temporary workers coming from urban areas. The displaced locals are predominantly moving to the cities (Diaz-Chavez et al., 2015), losing their rural culture (Comin et al., 2009). It is, therefore, reasonable to expect that human hunting pressure on jaguars and their prey might decrease. In addition, the reduction of conflict with livestock, because of land-use change, is likely to decrease retaliation on jaguars. Wild boars are now widespread in the state of São Paulo (Pedrosa et al., 2015; Salerno, 2015), including areas of Eucalyptus and sugarcane plantations (Fig. 1). Jaguars are able to prey upon well-armed large animals such as caimans Caiman yacare and tapirs Tapirus terrestris (Azevedo & Verdade, 2012), making wild boar a potential prey. This combination of low hunting pressure and high prey abundance in these agricultural landscapes might increase the opportunity for jaguars to move over large distances, possibly connecting the remaining isolated populations of the species in the eastern and western regions of the state (respectively, 'Serra do Mar' and 'Morro do Diabo' State Parks). If this does occur, population expansion and connection might increase the jaguar population's genetic variability, which is currently low (Haag et al., 2010). Land use and current distribution of jaguars Panthera onca (IUCN 2014) and introduced wild boars Sus scrofa (Salerno, 2015) in São Paulo, Brazil. Sugarcane (Rudorff et al., 2010) and Eucalyptus (Instituto Florestal, 2005) plantations have been replacing pasturelands in the last decades. Although, paradoxically dependent on the introduction of a highly invasive exotic species and on the land-use change in agricultural landscapes, the recovery of a top predator is desirable from conservationists' point of view, but it imposes challenges for the field of wildlife management. In such contexts, governance is crucial to mitigate the inevitable conflicts due to concerns about the security of agricultural workers, the potential increase in road accidents and the spread of diseases (e.g. rabies). In order to confront these challenges, the following issues need to be addressed: (1) wild boars are considered to be the most invasive vertebrate in the world (Barrios-Garcia & Ballari, 2012); the cost of their control could be considerably reduced in the presence of jaguars; (2) agricultural landscapes should be multifunctional with a primary mission of producing crops and domesticated livestock, but also a secondary mission of conserving wild species (Verdade et al., 2014); and last but not least, (3) capacity building in the field of wildlife management should be stimulated in Brazil (Verdade, 2004). Many countries have been facing conflicts related to the recovery of large predators (Marchini, 2014), and their experience would be invaluable in such a task. In addition, the following research questions might be addressed by conservation scientists in order to evaluate the feasibility of the future scenario posed in this letter: (1) What is the current jaguar carrying capacity of Eucalyptus and sugarcane agricultural landscapes in relation to the pristine areas of Atlantic Forest where the species is still found in São Paulo? (2) How will land-use change and agriculture intensification affect such carrying capacity? (3) How does jaguar's diet and health status (i.e. pathogens/parasites prevalence and contamination by agrochemical residues) vary in such conditions? (4) What is the role of predation by jaguars on the demography of wild boar and how does this predator–prey relationship vary with time? (5) Is the genetic variability of Atlantic forest jaguar population great enough to ensure long-term viability of the population in such conditions? and, finally (6) Can we predict jaguar's demographic response to the scenario proposed in this letter? We call upon conservation scientists to help provide the answer to these questions and to support the long-term sustainability of this iconic Neotropical species.