Evaluation of Global Positioning System telemetry collar performance in the tropical Andes of southern Ecuador

Abstract

The objective of this study was to evaluate if canopy cover, topographic obstruction of the sky, and differences among vegetation type affected performance of global positioning system (GPS) telemetry in southern Ecuador. A GPS collar was placed at 30 test sites in Podocarpus National Park, Ecuador, and we estimated canopy cover and topographic obstruction at each site. The mean fix success rate was 87.7% (SD=22.3%), and the mean location error for test sites was 9.7m (SD=4.17m). Canopy cover significantly reduced the performance of GPS telemetry in our study area both in terms of location error and fix acquisition rate. However, topographic obstruction did not significantly influence location errors or fix acquisition rate. Screening data to remove less accurate, two-dimensional fixes resulted in an 11% data loss and reduced the mean location error by 3.8m. Understanding how habitat variables influence fix acquisition and location errors of GPS collars will assist researchers in evaluating potential biases and developing methods to correct for the effect of such biases on analyses of habitat use and animal movements in the tropical Andes in southern Ecuador.