Impacts of translocation on a large urban-adapted venomous snake

Abstract

Context Translocation as a tool for management of nuisance or ‘problem’ snakes near urban areas is currently used worldwide with limited success. Translocated snakes experience modified behaviours, spatial use and survivorship, and few studies have investigated the impacts of translocation within a metropolitan area. Aims In the present study, we investigated the impacts of translocation on the most commonly encountered snake in Perth Western Australia, the dugite (Pseudonaja affinis, Elapidae), by comparing the space use of resident and translocated snakes. Methods We captured 10 dugites and attached telemetry packages, composed of a radio-telemetry transmitter and global positioning system (GPS) data-logger, externally to their tails. Snakes were either released within 200 m of their initial capture sites (residents, n = 6) or moved to new unconnected habitat at least 3 km away (translocated, n = 4). Spatial-use data were analysed using general linear models to identify differences between resident and translocated dugites. Key results Translocation influenced space use of dugites and detrimentally affected their survivorship. Translocated snakes had larger activity ranges than did residents, and there was a trend towards travelling greater distances over time. Mortality for all snakes was high: 100% for translocated snakes, and 50% for residents. Conclusions Urban dugites face many threats, and snakes were negatively affected by translocation. The GPS technology we used did not improve the quality of the data over traditional radio-telemetry methods, owing to the cryptic nature of the snakes that spent much of their time under cover or underground. Implications These findings support the growing body of evidence that translocating ‘problem’ snakes is a not a humane method of animal management, and alternatives such as public education, may be more appropriate.

Reptiles on the wrong track? Moving beyond traditional estimators with dynamic Brownian Bridge Movement Models

“…Furthermore, dBBMMs require no a priori knowledge of an animal’s movements (necessary to identify the correct smoothing bandwidth for KDEs), and can be put to use with current telemetry practices or to re-analyse previously collected data. The dBBMM method is easily compatible with low-resolution data from herpetofauna spatial ecology studies still reliant on VHF, representing a cheap and immediate alternative to long-term high-resolution tracking methods (GPS) that remain elusive for herpetofauna [ 30 , 80 ]. Presently, applications of dBBMMs to reptile movement data are still restricted to a single field site [ 31 , 74 ].…”

“…The method creates a one-dimensional fix-frequency independent behavioural measure (Brownian motion variance [ 20 ]) that has been employed to elucidate avian and mammal movement patterns and provides a confidence region of where the movement pathways fall (e.g., [ 21 – 24 ]). While tracking reptiles with GPS may currently be limited (see [ 25 – 28 ]) by their natural history [ 29 , 30 ] —e.g. weakened signal due to the surgical implantation, attachment of the tag, limited number of species which can be ethically attached due to body size [ 28 ], reduced fix rates and precision due to underground sheltering [ 16 , 30 ]— leveraging dBBMMs may still benefit reptile VHF studies [ 31 , 32 ].…”

“…While tracking reptiles with GPS may currently be limited (see [ 25 – 28 ]) by their natural history [ 29 , 30 ] —e.g. weakened signal due to the surgical implantation, attachment of the tag, limited number of species which can be ethically attached due to body size [ 28 ], reduced fix rates and precision due to underground sheltering [ 16 , 30 ]— leveraging dBBMMs may still benefit reptile VHF studies [ 31 , 32 ]. Multiple simulations studies have investigated how different methods interact with animal movement and space-use delineation (e.g., [ 18 , 33 – 35 ]), but none have targeted reptile-specific movement patterns.…”

No room to roam: King Cobras reduce movement in agriculture

“…Further, changes in site reuse may be present at finer temporal scales than the intensity of our tracking regime. Longterm GPS tracking of snakes presently appears unfeasible [111]. Technological advances may enable more intensive and consistent tracking of individuals, allowing for identification of subtler behavioural and movement responses to anthropogenic landscapes.…”

Make like a glass frog: In support of increased transparency in herpetology

“…Low sample sizes result in underpowered tests, variable effect sizes, and unreliable results that exacerbate false positives (Barto & Rillig, 2012;Christie et al, 2019;Forstmeier et al, 2017;Jennions & Møller, 2002). However, being able to combine these results from small studies will be even more valuable in cases where samples are limited by low-detection rates (Boback et al, 2020;Durso & Seigel, 2015;Steen, 2010), technological limitations (Wolfe et al, 2018), and logistical obstacles (Christie et al, 2019). When fully and transparently reported, smaller studies expand and refine broader knowledge (Lemoine et al, 2016).…”