Jaguar Panthera and Tiger Jaguar

The Jaguar Panthera onca, categorized as Near Threatened on the IUCN Red List (IUCN, 2003), is the largest felid in the western hemisphere and the third largest felid worldwide. Jaguars are distributed from northern Mexico to Argentina and inhabit areas in the arid scrublands of northern Mexico, the moist tropical forests of Central and South America, and the grasslands of the Pantanal in Brazil. The jaguar is a landscape species (i.e. occupying large home ranges that often extend beyond protected area boundaries, having a significant impact on the structure and function of ecosystems, and requiring a diversity of ecosystem types; Coppolillo et al., in press; Sanderson et al., 2002a).

Jaguars are currently threatened by the effects of habitat destruction and fragmentation, illegal hunting and prey depletion. The current estimated known range of the jaguar is thought to be <50% of its range in 1900, although 70% of the area within their current range is thought to have a high probability of being able to support their long-term survival (Sanderson et al., 2002b).

Jaguar Panthera

Like many other large felids, jaguars are difficult to monitor because of their cryptic nature, large home range sizes, and low population densities. Recent efforts to develop a range-wide approach to jaguar conservation (Sanderson et al., 2002b) brought to light a lack of population data for the species. Despite more than three decades of field research on jaguars, few studies have estimated
jaguar populations. Where estimates have been made, they are usually based upon assumptions about the occurrence and home range sizes of a few individuals (Schaller & Crawshaw, 1980; Rabinowitz & Nottingham, 1986; Crawshaw & Quigley, 1991; Aranda, 1998). Toachieve conservation objectives that adequately protect jaguar populations, conservation planners need accurate estimates of densities across a variety of habitats.

In an effort to provide a population monitoring technique that can be used throughout the jaguars’ range, we adapted a method first developed and implemented to monitor tiger Panthera tigris populations in India. The technique takes advantage of distinctive individual markings through photographs taken with remote camera stations, and applies the theoretical framework of mark/recapture models to estimate population abundance.

Jaguar

The third site in Bolivia was an Amazonian rainforest site in the Madidi National Park and Natural Area of Integrated Management. The region is characterized by a marked dry season between April and November and a mean annual precipitation of 2,230 mm. This forest is characterized by a relatively open canopy and a large proportion of palms of the genera Scheelea, Astrocaryum,
Socratea and Jessenia. For 8 years before the creation of the Madidi protected area in 1995 the area was exploited for high-value commercial timber species. The camp was situated at Pacaysal on the Tuichi River and at Marihui on the Hondo River. Cameras were placed during the dry season on beaches along the Tuichi and Hondo rivers and several smaller tributaries, as well as on a grid of
trails established between 2001 and 2002 immediately prior to and during the survey.

The final major assumption of the model is that no jaguars within the sampled area have a zero probability of being captured. The smallest conservatively estimated home range size for jaguar is 10 km2 for a female jaguar in a Central American tropical forest habitat (Rabinowitz & Nottingham, 1986). With no data from the dry forest Chaco sites in Bolivia, we assumed home ranges in the
Chaco to be roughly twice as large (20 km2) for a female jaguar. Consequently, we placed cameras such that no areas without cameras greater than 10 km2 (rainforest in Belize and Bolivia) or 20 km2 (dry Chaco forest in Bolivia) existed within the sample area.