Informe Científico-técnico al Lincoln Park Zoo

DI BITETTI, M. S.; PAVIOLO, A.; DE ANGELO, C. D.

2008-01-01/2008-12-31

1-11

Biológica

Rec.Nat.Renov.-Conservacion y preservacion

This project is aimed at assessing the status of the jaguar (Panthera onca) population of the Upper Paraná Atlantic Forest ecoregion and, in particular, of the Green Corridor of Misiones, Argentina, the largest forest remnant of this ecoregion. This information has been used to develop a population viability analysis (PVA) of this jaguar population, a work that scientific staff from Lincoln Park Zoo is doing as part of this collaboration (Lonsdorf et al. unpublished manuscript). The results of our research work and the PVA are also being used to develop a Conservation Plan for this endangered jaguar population. Since 2003 we are conducting camera-trap surveys to estimate jaguar densities. Simultaneously and with the aid of a network of 150 volunteers from Paraguay, Brazil and Argentina, we are gathering information on jaguar presence on all the forests remnants of this ecoregion. We are evaluating the effect of potential factors that may affect the abundance of this top predator (land use patterns, protection, hunting pressure, prey availability, competition with other large predators). We are estimating jaguar densities using photographic records of individually identified jaguars obtained with camera-traps. The method to estimate absolute densities of jaguars with camera-traps is based on classical methods to estimate animal densities using the capture-mark-recapture technique. With the jaguar density estimates and with maps of jaguar distribution in the Green Corridor based on presence-absence data, we are estimating the size of this jaguar population (Paviolo et al. 2008, De Angelo 2009). The camera trap surveys are also providing population estimates of potential competitors of jaguars: pumas (Puma concolor; Kelly et al. 2008, Paviolo et al. 2009) and ocelots (Leopardus pardalis; Di Bitetti et al. 2006, 2008).  The camera-trap surveys are also providing information on the presence and relative abundance of other large and medium size mammals, which constitute the most important prey items in the jaguar´s diet. To assess the impact of hunting and protection on jaguar´s prey abundance (and indirectly on this cat´s abundance) we correlate our estimates of relative prey abundance with the degree of poaching and the degree of protection of the different areas where we conduct our surveys. Our results suggest that protection from poaching is the major factor responsible for the abundance of the main jaguar prey (Di Bitetti et al. 2008, Paviolo et al. in prep.) and of the large cats (Di Bitetti et al. 20006, 2008, Paviolo et al. 2008, 2009). We are also interested in understanding the ecological role played by jaguars and pumas in regulating the populations of its prey and medium size carnivores and the consequent trophic cascades (Di Bitetti 2008). Both the results of our jaguar work and the results of the PVA are being used to develop a Conservation Plan for this jaguar population. For the following years we are planning to conduct camera-trap surveys in the northern part of the Green Corridor at regular intervals (every 1-2 years) to get information on population turnover rates.  We are also planning to conduct future camera-trap surveys in other areas (Yabotí Biosphere Reserve, Yungas in NW Argentina) to monitor the status of the jaguar populations. In 2009 we are planning to capture at least five jaguars in the Iguazú-San Jorge area to fit them with GPS collars and monitor their movements. Our plan is to monitor at least 10 jaguars with GPS collars during the next two years. This will help us understand how jaguars use the landscape. This is important information to develop accurate models of jaguar landscape use and to understand how the ongoing changes in the landscape could affect jaguars, information that could be incorporated into the PVA and the Jaguar Conservation Plan.