Stress responses to repeated captures in a wild ungulate

Abstract

While capture-mark-recapture studies provide essential individual-level data in ecology, repeated captures and handling may impact animal welfare and cause scientific bias. Evaluating the consequences of invasive methodologies should be an integral part of any study involving capture of live animals. We investigated short- and long-term stress responses to repeated captures within a winter on the physiology, behaviour, and reproductive success of female Svalbard reindeer (Rangifer tarandus platyrhynchus). Short-term responses were evaluated using serum concentrations of glucocorticoids and catecholamines during handling, and post-release recovery times in heart rate and activity levels. Repeated captures were associated with an increase in measured catecholamines and glucocorticoids, except cortisone, and delayed recovery in heart rate but not activity. Four months later, in summer, individuals captured repeatedly in winter exhibited a small increase in behavioural response to human disturbance and had a lower probability of being observed with a calf, compared to animals not captured, or captured only once. Our findings imply that single annual capture events have no significant negative consequences for Svalbard reindeer, but repeated captures within a season may impact offspring survival in the same year. Such unanticipated side effects highlight the importance of addressing multiple indicators of animal responses to repeated captures.

Thermal and behavioural responses of moose to chemical immobilisation from a helicopter

“…Examples of long-term effects of stressful situations include changes in body condition, calf survival rates, immune suppression, and habitat changes on an individual level, which could impact population dynamics due to reduced survival and reproductive rates (McLaren et al 2007;Moberg 2000). The literature on the long-term effects of immobilisation in free-ranging ungulates is limited with inconsistent conclusions (Larsen and Gauthier 1989;Omsjoe et al 2009;Trondrud et al 2022). A follow-up to the present study to evaluate long-term effects could be to look at the post-natal survivorship and slaughter weights of calves born in the spring after the immobilisation, as well as the reproductive rates of the females in the following years and their slaughter weights.…”

“…Chemical immobilisation of free-ranging wildlife will always include the risk of adverse effects and mortality even in healthy animals, and mortality rates have traditionally been used to describe the negative impacts of wildlife capture (Hampton and Arnemo 2022;Kreeger and Arnemo 2018). In recent years, however, more studies have focused on the non-lethal adverse effects, including short-term physiological and behavioural effects on the individual animal and long-term impacts on both the individual and the population (Cattet et al 2008;Hampton and Arnemo 2022;Trondrud et al 2022). All stages of the immobilisation procedure could influence the animal both physiologically and behaviourally, and it is often not possible to distinguish which part of the capture process it comes from.…”

Hand grab or noose pole? Evaluating the least stressful practice for capture of endangered Turks and Caicos Rock Iguanas Cyclura carinata

“…For health examinations to remain both ethical and beneficial it is also important to consider how the method of capture and restraint of sampled individuals can affect their overall welfare. To this end, among the many parameters measured by point-of-care analyzers, lactate is gaining much attention as it is often used as a proxy to evaluate stress level, generally considered an indicator of animal welfare, of sampled individuals ( Trondrund et al, 2022 ). A number of studies have shown how lactate levels in the blood can be used as a diagnostic tool for chronic conditions, but also as an indicator of stress associated with struggling, fear, and/or bursts of intense muscular activity in a number of species ( Rand et al, 2002 ; Klein et al, 2020 ; Trondrund et al, 2022 ).…”

Captures do not affect escape response to humans in Alpine marmot

“…To date, studies in reptiles and birds showed an increase in flight initiation distance to humans associated with capture and handling, likely due to aversive conditioning (Smith, 1996;Griffin and Boyle, 2009;Kidd-Weaver et al, 2022). In mammals, knowledge is more scant (Zaman et al, 2019;Trondrud et al, 2022), and also somewhat controversial: on the one hand, Zaman et al (2019) found no effect of captures on susceptibility to humans in golden marmotsMarmota caudata aurea . On the other hand, Trondrud et al (2022) showed a positive relationship between repeated captures within the same year and response behaviours towards humans in Svalbard reindeerRangifer tarandus platyrhynchus .…”