Immediate response to translocation without acclimation from captivity to the wild in Hermann’s tortoise

The fitness consequences of wildlife conservation translocations: a meta-analysis

Conservation translocation is a common strategy to offset mounting rates of population declines through the transfer of captive- or wild-origin organisms into areas where conspecific populations are imperilled or completely extirpated. Translocations that supplement existing populations are referred to as reinforcements and can be conducted using captive-origin animals [ex situ reinforcement (ESR)] or wild-origin animals without any captive ancestry [in situ reinforcement (ISR)]. These programs have been criticized for low success rates and husbandry practices that produce individuals with genetic and performance deficits, but the post-release performance of captive-origin or wild-origin translocated groups has not been systematically reviewed to quantify success relative to wild-resident control groups. To assess the disparity in post-release performance of translocated organisms relative to wild-resident conspecifics and examine the association of performance disparity with organismal and methodological factors across studies, we conducted a systematic review and meta-analysis of 821 performance comparisons from 171 studies representing nine animal classes (101 species). We found that translocated organisms have 64% decreased odds of out-performing their wild-resident counterparts, supporting claims of systemic issues hampering conservation translocations. To help identify translocation practices that could maximize program success in the future, we further quantified the impact of broad organismal and methodological factors on the disparity between translocated and wild-resident conspecific performance. Pre-release animal enrichment significantly reduced performance disparities, whereas our results suggest no overall effects of taxonomic group, sex, captive generation time, or the type of fitness surrogate measured. This work is the most comprehensive systematic review to date of animal conservation translocations in which wild conspecifics were used as comparators, thereby facilitating an evaluation of the overall impact of this conservation strategy and identifying specific actions to increase success. Our review highlights the need for conservation managers to include both sympatric and allopatric wild-reference groups to ensure the post-release performance of translocated animals can be evaluated. Further, our analyses identify pre-release animal enrichment as a particular strategy for improving the outcomes of animal conservation translocations, and demonstrate how meta-analysis can be used to identify implementation choices that maximize translocated animal contributions to recipient population growth and viability.

Chronic captivity stress in wild animals is highly species-specific

Wild animals are brought into captivity for many reasons-conservation, research, agriculture and the exotic pet trade. While the physical needs of animals are met in captivity, the conditions of confinement and exposure to humans can result in physiological stress. The stress response consists of the suite of hormonal and physiological reactions to help an animal survive potentially harmful stimuli. The adrenomedullary response results in increased heart rate and muscle tone (among other effects); elevated glucocorticoid (GC) hormones help to direct resources towards immediate survival. While these responses are adaptive, overexposure to stress can cause physiological problems, such as weight loss, changes to the immune system and decreased reproductive capacity. Many people who work with wild animals in captivity assume that they will eventually adjust to their new circumstances. However, captivity may have long-term or permanent impacts on physiology if the stress response is chronically activated. We reviewed the literature on the effects of introduction to captivity in wild-caught individuals on the physiological systems impacted by stress, particularly weight changes, GC regulation, adrenomedullary regulation and the immune and reproductive systems. This paper did not review studies on captive-born animals. Adjustment to captivity has been reported for some physiological systems in some species. However, for many species, permanent alterations to physiology may occur with captivity. For example, captive animals may have elevated GCs and/or reduced reproductive capacity compared to free-living animals even after months in captivity. Full adjustment to captivity may occur only in some species, and may be dependent on time of year or other variables. We discuss some of the methods that can be used to reduce chronic captivity stress.

Impacts of translocation on a large urban-adapted venomous snake

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.

Uncovering environmental, land-use and fire effects on the distribution of a low-dispersal species, the Hermann’s tortoise Testudo hermanni

Habitat destruction has resulted in the fragmented distribution of numerous terrestrial species, which poses a challenge for conservationists. Furthermore, species management can be further compounded by life history constraints such as low dispersal, hindering the ability of species to recolonize areas they formerly occupied. For these species, a thorough understanding of the local threats and factors that limit their distribution is crucial for effective management. We used occupancy models to examine which factors at landscape and habitat scales (i.e. land uses, fire history, and vegetation structure) explain the presence of terrestrial tortoises within the range of the westernmost isolated population of the endangeredTestudo hermanni hermanniin the Albera Range (NE of the Iberian Peninsula). We randomly surveyed 25 sites (75% of the area known with presence of tortoises) of natural woodlands with 5 to 8 replicates per site in spring 2012-2014. From a sampling effort of 148 hours, we only detected 52 tortoises in 12 of 25 transects. These low numbers are evidence of low population densities. Sites with presence of tortoises were spatially aggregated although the species was absent from apparently adequate sites on the edges of its distribution range. Current and historic land-use primarily explained the presence of tortoises. Besides, wildfires and reduction of habitat complexity also participate to explain the distribution of Hermann’s tortoises. We also discuss some aspects of the conservation ofTestudo hermanniin relation to our results.

Sex-specific ecophysiological responses to environmental fluctuations of free-ranging Hermann's tortoises: implication for conservation

Physiological parameters provide indicators to evaluate how organisms respond to conservation actions. For example, individuals translocated during reinforcement programmes may not adapt to their novel host environment and may exhibit elevated chronic levels of stress hormones and/or decreasing body condition. Conversely, successful conservation actions should be associated with a lack of detrimental physiological perturbation. However, physiological references fluctuate over time and are influenced by various factors (e.g. sex, age, reproductive status). It is therefore necessary to determine the range of natural variations of the selected physiological metrics to establish useful baselines. This study focuses on endangered free-ranging Hermann's tortoises (Testudo hermanni hermanni), where conservation actions have been preconized to prevent extinction of French mainland populations. The influence of sex and of environmental factors (site, year and season) on eight physiological parameters (e.g. body condition, corticosterone concentrations) was assessed in 82 individuals from two populations living in different habitats. Daily displacements were monitored by radio-tracking. Most parameters varied between years and seasons and exhibited contrasting sex patterns but with no or limited effect of site. By combining behavioural and physiological traits, this study provides sex-specific seasonal baselines that can be used to monitor the health status of Hermann's tortoises facing environmental threats (e.g. habitat changes) or during conservation actions (e.g. translocation). These results might also assist in selection of the appropriate season for translocation.