Individual heterogeneity influences the effects of translocation on urban dispersal of an invasive reptile

Abigail B Feuka; Melia G Nafus; Amy A Yackel Adams; Larissa L Bailey; Mevin B Hooten

doi:10.1186/s40462-022-00300-1

Individual heterogeneity influences the effects of translocation on urban dispersal of an invasive reptile

Mov Ecol. 2022 Jan 15;10(1):2. doi: 10.1186/s40462-022-00300-1.

Authors

Abigail B Feuka^{1

2}, Melia G Nafus³, Amy A Yackel Adams³, Larissa L Bailey⁴, Mevin B Hooten⁵

Affiliations

¹ U.S. Department of Agriculture Animal and Plant Health Inspection Service, National Wildlife Research Center, 4101 Laporte Ave, Fort Collins, CO, 80521-2154, USA. abigail.feuka@usda.gov.
² Colorado State University, Department of Fish, Wildlife, and Conservation Biology and Graduate Degree Program in Ecology, Fort Collins, CO, 80523-1474, USA. abigail.feuka@usda.gov.
³ U.S. Geological Survey, Fort Collins Science Center, 2150 Centre Avenue, Building C, Fort Collins, CO, 80526-8118, USA.
⁴ Colorado State University, Department of Fish, Wildlife, and Conservation Biology and Graduate Degree Program in Ecology, Fort Collins, CO, 80523-1474, USA.
⁵ The University of Texas at Austin, Department of Statistics and Data Sciences, Welch 5.216, 105 E 24th St D9800, Austin, TX, 78705-1576, USA.

Abstract

Background: Invasive reptiles pose a serious threat to global biodiversity, but early detection of individuals in an incipient population is often hindered by their cryptic nature, sporadic movements, and variation among individuals. Little is known about the mechanisms that affect the movement of these species, which limits our understanding of their dispersal. Our aim was to determine whether translocation or small-scale landscape features affect movement patterns of brown treesnakes (Boiga irregularis), a destructive invasive predator on the island of Guam.

Methods: We conducted a field experiment to compare the movements of resident (control) snakes to those of snakes translocated from forests and urban areas into new urban habitats. We developed a Bayesian hierarchical model to analyze snake movement mechanisms and account for attributes unique to invasive reptiles by incorporating multiple behavioral states and individual heterogeneity in movement parameters.

Results: We did not observe strong differences in mechanistic movement parameters (turning angle or step length) among experimental treatment groups. We found some evidence that translocated snakes from both forests and urban areas made longer movements than resident snakes, but variation among individuals within treatment groups weakened this effect. Snakes translocated from forests moved more frequently from pavement than those translocated from urban areas. Snakes translocated from urban areas moved less frequently from buildings than resident snakes. Resident snakes had high individual heterogeneity in movement probability.

Conclusions: Our approach to modeling movement improved our understanding of invasive reptile dispersal by allowing us to examine the mechanisms that influence their movement. We also demonstrated the importance of accounting for individual heterogeneity in population-level analyses, especially when management goals involve eradication of an invasive species.

Keywords: Bayesian hierarchical model; Boiga irregularis; Brown treesnake; Recursive computing; State space model; Translocation.

Grants and funding

1614392/Division of Mathematical Sciences