Devaux B.,Center for Research and Conservation of Chelonians |
Ballouard J.-M.,Center for Research and Conservation of Chelonians |
Caron S.,Center for Research and Conservation of Chelonians |
Servant L.,Center for Research and Conservation of Chelonians |
And 2 more authors.
Amphibia Reptilia | Year: 2013
Most species of tortoises are seriously threatened worldwide. Chelonians are long-lived organisms characterized by slow demographic traits; mathematical modeling estimated that a high rate of juvenile annual survival (i.e. >0.6 on average) is essential for the persistence of populations. Unfortunately, current knowledge about free-ranging juveniles is fragmentary. Under field conditions, young tortoises are very secretive, they remain sheltered beneath bushes, and they escape capture. The resulting lack of information impairs the assessment of key parameters such as juvenile survival, habitat use, or recruitment rate and thus seriously impedes both accurate population viability analyses and conservation planning. Large-scale monitoring of different populations of a threatened species (Testudo hermanni hermanni) confirmed that juveniles are rarely seen in the field. In 2011, we placed corrugated fibrocement slabs as alternative refuges for small tortoises in a densely vegetated study site. Many juveniles sheltered under the space offered by the corrugations; consequently they were easily captured and recaptured. Our results suggest that this simple technique may significantly improve the detectability of juveniles, providing access to the life history traits of this otherwise elusive age cohort. The slabs also provide protection against predators (such as dogs and birds) which further suggests that these refuges may also improve the survival of the smallest and most vulnerable individuals. © Koninklijke Brill NV, Leiden, 2013.
PubMed | Center for Research and Conservation of Chelonians, CNRS Chizé Center for Biological Studies and Deakin University
Type: Journal Article | Journal: Conservation physiology | Year: 2016
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 Hermanns tortoises (