Using Relative Abundance Indices from Camera-Trapping to Test Wildlife Conservation Hypotheses – An Example from Khao Yai National Park, Thailand

Abstract

Khao Yai National Park (KYNP) is well known for its biodiversity and has the potential to serve as a regional model for wildlife conservation. From October 2003 through October 2007, the managers of KYNP conducted a Carnivore Conservation Project to develop and implement long-term monitoring of their large mammal populations. We present these data as an example to demonstrate the usefulness of long-term camera-trapping despite data that cannot be fitted to mark/recapture or occupancy statistical frameworks. Overall, a relatively high number of camera trap photographs was obtained for viverrids (four species; 44 photos) and ursids (two species; 39 photos). However, a relatively low number (range, one to eight) of camera trap photographs was obtained for each of the four felid species and two canid species detected by cameras. Of a total survey effort of 6,260 trap nights, no tigers (Panthera tigris) were detected by camera traps, suggestive of at best a small, non-viable tiger population. Compared to previous camera-trapping efforts at KYNP, we expanded intensive sampling beyond the core area to include all zones and edges of the park. We found significantly lower relative abundance indices (RAIs) for certain mammal species, and collectively for all mammals compared to data obtained in 1999–2000 from 34 similar survey locations, suggesting population declines linked to increased human activity. Information from long-term camera-trapping can provide critical information on the occurrence of elusive species, hotspots, the role of invasive or domestic species, and an indication of the effectiveness of patrolling and other management and conservation interventions.

Mapping the distribution of dholes, Cuon alpinus (Canidae, Carnivora), in Thailand

“…there relative to the safer core area. The observation that wildlife abundance is higher in central parts of protected areas vs. marginal areas has been specifi cally documented in KY (Lynam et al 2003, Jenks et al 2011. Current protection efforts are most intense in areas close to a park or sanctuary headquarters, with remote areas getting less protection.…”

Terrestrial mammal assemblages in protected and human impacted areas in Northern Brazilian Amazonia

“…Relative abundance was calculated as number of species individual records multiplied by 100, and divided by sample effort (Jenks et al 2011). Kruskall-Wallis test was used in order to verify it there was any statistically significant difference in mean relative abundance among the areas, and Mann-Whitney to verify if there was any statistically significant difference in mean relative abundance between protected and impacted areas.…”

El jaguar Panthera onca (Carnivora: Felidae) en la Reserva de la Biosfera “El Cielo”, Tamaulipas, México

“…Abundancia relativa de presas potenciales: Para obtener el índice de abundancia relativa (IAR) de presas potenciales del jaguar se utilizó la siguiente fórmula (Maffei et al, 2002;Sanderson 2004;Azuara, 2005;Jenks et al, 2011;Zamora, 2012): IAR = [C/EM]*(1 000 días trampa) Donde: C es el número de eventos videográficos (independientes); EM es el esfuerzo de muestreo (medido como número de cámaras multiplicado por los días de monitoreo) estacional o total y 1 000 días -trampa (unidad estándar).…”

“…Se consideraron como registros independientes los siguientes casos: a) videos consecutivos de diferentes individuos y/o especies, y b) videos consecutivos de la misma especie separados por 60 min (este criterio fue aplicado cuando no era claro si una serie de videos correspondía a la misma presa, de modo que los videos tomados antes de 60 min se consideraron como un solo registro) (Maffei et al, 2002;Sanderson, 2004;Azuara, 2005;Jenks et al, 2011;Zamora, 2012).…”