Hurricane‐associated population decrease in a critically endangered long‐lived reptile

Abstract

Catastrophic events, like hurricanes, bring lethal conditions that can have population‐altering effects. The threatened Caribbean dry forest occurs in a region known for its high‐intensity hurricane seasons and high species endemism, highlighting the need to better understand hurricane impacts in combination with habitat fragmentation and loss. However, such studies remain rare and for reptiles are mostly restricted to Anolis. Here, we used single‐season occupancy modeling to infer the impact of the intense 2017 Atlantic hurricane season on the critically endangered Lesser Antillean Iguana, Iguana delicatissima. We surveyed 30 transects across eight habitats on St. Eustatius during 2017–2019, which resulted in 344 individual surveys and 98 iguana observations. Analyses of abundance and site occupancy indicated both measures for 2018 and 2019 were strongly reduced compared to the pre‐hurricane 2017 state. Iguanas at higher elevations were affected more profoundly, likely due to higher wind speeds, tree damage, and extensive defoliation. Overall, our results indicate a decrease in population estimates (23.3%–26.5%) and abundance (22%–23.8%) for 2018 and 2019, and a 75% reduction in opportunistic sightings of tagged iguanas between 2017 and 2018. As only small and isolated I. delicatissima populations remain, our study further demonstrates their vulnerability to stochastic events. Considering the frequency and intensity of hurricanes are projected to increase, our results stress the urgent need for population‐increasing conservation actions in order to secure the long‐term survival of I. delicatissima throughout its range. Given the projected increase and poleward shift of hurricanes, our study provides important insights from a non‐model species.

Population estimate, natural history and conservation of the melanistic Iguana Iguana population on Saba, Caribbean Netherlands

“…This long overdue population estimate serves as an important preliminary baseline for longterm monitoring. For future comparison it is important to note that data collection occurred four years after the 2017 hurricane season, which was the strongest-recorded Atlantic hurricane season on record and strongly affected iguana populations on other islands (Schultz et al 2018; van den Burg et al 2022a). Similarly, on Saba, both forests and the Red-bellied Racer population were affected by hurricanes during 2017 (Eppinga and Cucko 2018; Madden and Mielke 2021).…”

“…coastal development), hunting (e.g. iguanas), illegal trade and stochastic events like hurricanes (Johnson and Winker 2010; Medina et al 2011; Meléndez-Vazquez et al 2019; van den Burg et al 2022a). In the West Indies, 80% of species extinctions have primarily been caused by biological invasions and the region continues to be a “hotspot” of insular extinctions (Leclerc et al 2018).…”