Using camera traps to estimate site occupancy of invasive Argentine Black and White Tegus (Salvator merianae) in South Florida

Abstract

The introduction of nonnative species is a leading cause of biodiversity loss. Many invasive species are cryptic or elusive in nature and therefore often evade detection, complicating their management. Occupancy modeling can reveal the presence and spread of invasive species over time and therefore has important management implications. Camera traps can be used to estimate occupancy, or the proportion of sites that are occupied by a target species. During a 4-year study (2016–2020), we used camera traps both with and without lures to detect the presence of invasive Salvator merianae (Argentine Black and White Tegu) at sites in Miami-Dade County, FL. Our results from a multi-season occupancy model revealed that a quadratic effect of ordinal day was the best predictor of detection, with a peak in June, while occupancy was correlated with distance to landscape features that may facilitate tegu movement. We did not detect any large-scale changes in occupancy over the course of our study. We also discovered that the use of lures with camera traps did not impact detection, indicating fewer resources would be required from invasive species managers for effective monitoring. Understanding the factors that impact occupancy and detection probabilities can inform surveillance and removal efforts, leading to more efficient management strategies.