Comparing the effectiveness of tracking methods for medium to large-sized mammals of Pantanal

Relative abundances of medium and large mammals in the Cueva de Los Guácharos National Park (Huila, Colombia)

Abstract: Medium and large mammals are greatly affected by human activities, such as, habitat loss and hunting. In Colombia, these pressures have been most extensive in the dry and Andean forests. However, there is scare information available on the presence or abundance of these organisms for monitoring purposes. This study used photo-trapping cameras to determine the relative abundances of medium and large mammals in a mountain forest in the National Natural Park “Cueva de los Guacharos”, Huila (Colombia). Additionally, we examined whether trail use by humans could affect the distribution of these organisms. The cameras were located every 500 meters along the trails in strategic locations. We obtained the relative abundance of 11 species, being medium-sized mammals the most frequent (Cuniculus paca, Dasyprocta punctata and Mazama rufina). We recorded the presence of mountain tapir (Tapirus pinchaque), dwarf red brocket (Mazama rufina) and oncilla (Leopardus tigrinus), which are found in a high threat category according to the IUCN. Activity patterns were reported for 4 different species including daytime, nocturnal and cathemeral activities. Finally, we concluded that large mammals avoided trails of frequent use, and although the relative abundance of mammals is not very high, this National Park is still supporting relevant biodiversity.

Mammal inventories in Seasonal Neotropical Forests: traditional approaches still compensate drawbacks of modern technologies

ABSTRACT Variation in body size, behavior, feeding habits and habitat use patterns in medium- and large-sized mammals influence the adequacy of sampling methods to register presence and abundance. Moreover, even if methods are similarly adequate, different methodologies result in distinct cost-efficiency relationships (i.e. some may have reduced costs, be less time-consuming and/or require less-skilled technicians). Focusing on three different sampling methods commonly used to monitor medium and large mammals in seasonal tropical forests, we compared the species richness detected by each method and quantified their cost-efficiencies: (1) camera traps; (2) line transects for direct observations of animals; and (3) line transects seeking tracks/footprints. We simultaneously monitored medium and large mammals along five trails between July and August 2009 and January and February 2010, in the Serra do Japi Biological Reserve, São Paulo, Brazil. Data from two distinct seasons demonstrated that significantly higher species richness was achieved by using signs of presence and direct observations detected in transects. Camera traps recorded the fewest species, but represented the lowest cost per species. Direct observations and searches for tracks/footprints required a greater number of field technicians (with more skill and experience) to record the focal species and therefore have a higher cost, but allowed twice as many species to be recorded compared to camera traps. The choice of sampling methodology depends on the study objective, mammal species targeted and/or amount of resources available. We advocate use of camera traps for long-term studies and in conjunction with the other two methods to improve identification accuracy, allow individual identification and permit more accurate abundance estimates.