Supplementary feeding and young extraction from the wild are not a sensible alternative to captive breeding for reintroducing bearded vultures Gypaetus barbatus.

1. Reintroduction programmes need regular assessments of their achievements and cost-efficiency so as to adapt management strategy. Ferrer et al. argue that the reintroduction of the bearded vulture, which has so far relied upon the release of captive-reared chicks, could instead use the extra number of young produced by supplementary feeding on poor-quality territories in the Pyrenees. They argue that this strategy would not affect the donor population while being much cheaper than a captive breeding programme. We question this assertion based on several grounds. 2. Ferrer et al. used incorrect data when estimating the effects of supplementary feeding on the production of young. Our reanalyses using the same data source but corrected for missing values show effect sizes of low magnitude and with substantial uncertainty, questioning any positive effect of supplementary feeding on productivity. Moreover, Ferrer et al.’s experiment actually lacks a genuine statistical control due to weak temporal stability in territory quality: we demonstrate that average productivity of territories of low-quality during the baseline period (2001–2006) might actually have been increasing during the ‘treatment’ period (2007–2010) even without food supplementation due to a possible regression to the mean effect. 3. Our demographic reanalysis furthermore suggests that the donor population would not be that resilient to the extraction of young, resulting in trajectories far less optimistic (53–56 pairs in a time horizon of 50 years) than the 70 pairs reported. We also suggest that the costs of a captive breeding programme are substantially lower than suggested by Ferrer et al. 4. Synthesis and applications. The management recommendations proposed by Ferrer et al. appear unjustified. We thus urge governmental agencies to avoid making strategic political decisions and deploying conservation action on such a flawed base. We do not question here the utility of experimental approaches in reintroduction biology, but advocate independent assessment of study designs, data handling and quantitative analyses, notably when extraction of individuals from endangered populations is proposed as the best alternative option

Supplementary feeding and young extraction from the wild are not a sensible alternative to captive breeding for reintroducing bearded vultures Gypaetus barbatus

Reintroduction programmes need regular assessments of their achievements and cost-efficiency so as to adapt management strategy. Ferrer et al. argue that the reintroduction of the bearded vulture, which has so far relied upon the release of captive-reared chicks, could instead use the extra number of young produced by supplementary feeding on poor-quality territories in the Pyrenees. They argue that this strategy would not affect the donor population while being much cheaper than a captive breeding programme. We question this assertion based on several grounds. Ferrer et al. used incorrect data when estimating the effects of supplementary feeding on the production of young. Our reanalyses using the same data source but corrected for missing values show effect sizes of low magnitude and with substantial uncertainty, questioning any positive effect of supplementary feeding on productivity. Moreover, Ferrer et al.'s experiment actually lacks a genuine statistical control due to weak temporal stability in territory quality: we demonstrate that average productivity of territories of low-quality during the baseline period (2001–2006) might actually have been increasing during the ‘treatment’ period (2007–2010) even without food supplementation due to a possible regression to the mean effect. Our demographic reanalysis furthermore suggests that the donor population would not be that resilient to the extraction of young, resulting in trajectories far less optimistic (53–56 pairs in a time horizon of 50 years) than the 70 pairs reported. We also suggest that the costs of a captive breeding programme are substantially lower than suggested by Ferrer et al. Synthesis and applications. The management recommendations proposed by Ferrer et al. appear unjustified. We thus urge governmental agencies to avoid making strategic political decisions and deploying conservation action on such a flawed base. We do not question here the utility of experimental approaches in reintroduction biology, but advocate independent assessment of study designs, data handling and quantitative analyses, notably when extraction of individuals from endangered populations is proposed as the best alternative option.J.M. Martínez was supported by the Government of Aragón (projects RB34045 and RB44037). A. Margalida was supported by a Ramón y Cajal research contract from the Ministry of Economy and Competitiveness (RYC-2012-11867).Peer Reviewe

No evidence for genetic differentiation in juvenile traits between Belgian and French populations of the invasive tree Robinia pseudoacacia

Background – The role of evolution in biological invasion studies is often overlooked. In order to evaluate the evolutionary mechanisms behind invasiveness, both quantitative and population genetics studies are underway on Robinia pseudoacacia L., one of the worst invasive tree species in Europe.Methods – A controlled experiment was set up using 2000 seeds from ten populations in Southern France and ten populations in Belgium. Seedlings were cultivated in two climatic chambers set at 18°C and 22°C. Early development life history traits (e.g. seedling phenology) and functional traits (e.g. growth rates) were monitored. Genotyping using SNP markers was used to evaluate the genetic differentiation among the populations and a QST – FST comparison was done in order to test for the role of selection.Results – Populations exhibited a strong plasticity to temperature for all measured traits, the warmer environment being generally more suitable, irrespective of their origin. No significant departure from neutral evolution was evidenced by the QST – FST comparisons, although we found a slightly significant differentiation at the molecular level. Conclusion – Plasticity for the functional and life history traits was evidenced but no genetic interaction suggesting no possible evolution of plasticity at those traits. Moreover, no support for genetic differentiation and local adaptation was found among studied populations within invasive range, raising two main questions: first, what is the role of selection on functional and life-history traits; and second, is the elapsed time since first introduction sufficient to allow evolution and local adaptation