https://popups.lib.uliege.be/2984-0317/index.php?id=487 Entrées d’index fr 0 https://popups.lib.uliege.be/2984-0317/index.php?id=2205 Black Grouse, Capercaillie and Hazel Grouse are endangered in several central and west European countries. To augment or re-establish local populations of these species, releases of captive-reared birds have been conducted in many places. Provisional results of some releases were encouraging, but to date, none of these projects is known to have established a viable population. Factors that might cause a release to succeed or fail are still poorly understood. By viewing release projects as individual case studies, the compilation and synthesis of results of several studies should allow quantitative evaluation and determination of those factors that are essential for successful releases. We studied the feasibility of performing meta-analysis by reviewing published results of 29 documented release projects with Black Grouse. Capercaillie and Hazel Grouse, conducted between 1980 and 2000 in six European countries. In total, more than 5500 captive-reared birds were released within these projects. Due to lack of comparable information in the published reports, only few factors could be included in statistical evaluation. Among those, the total and the yearly number of birds released and the number of release years were the only significant predictors for project success. The resulting models suggest that annual releases of at least 30 birds are needed for a period of more than 6 years, to reach a 50% probability for survival and reproduction of released birds. Despite limitations in the data set, meta-analysis appeared to be a feasible tool for evaluation of grouse releases. To enhance future analyses, however, improved documentation of release projects is needed. We suggest a list of topics that authors should consider when reporting grouse release studies. Le Tétras lyre, le Grand Tétras et la Gélinotte des bois sont des espèces sérieusement en danger dans plusieurs contrées de l’Ouest européen. Pour étoffer ou réinstaller les populations locales de ces espèces, des lâchers d'oiseaux élevés en captivité ont fréquemment été tentés. Considérant chaque tentative ou projet comme un cas d'étude, il est permis de penser qu'une compilation et une synthèse des résultats de plusieurs essais pourraient fournir une évaluation quantitative des méthodes utilisées. Nous avons étudié la faisabilité d'une telle méta-analyse en passant en revue les résultats publiés de 30 lâchers bien documentés de tétraonidés, réalisés entre 1980 et 2000 dans six pays européens. Au total, plus de 5500 oiseaux élevés en captivité furent relâchés dans le cadre de ces programmes. Il apparaît que, au vu de la pauvreté en informations comparables dans les rapports publiés, quelques critères seulement ont pu faire l'objet d'une évaluation. Pour permettre une méta-analyse, une documentation améliorée est nécessaire. Nous proposons un ensemble de critères à prendre en compte lors de telles études de repeuplement, pour améliorer le développement et l’instrumentation de stratégies effectives pour la reconstitution d'espèces menacées de tétraonidés. Birkhuhn, Auerhuhn und Haselhuhn sind in vielen westeuropäischen Ländern in ihrem Bestand gefährdet. Um lokale Populationen dieser Arten zu erhalten oder wieder anzusiedeln, wurden in einigen Gebieten gefangenschaftsaufgezogene Vögel freigelassen. Betrachtet man einzelne Freilassungsprojekte als Fallstudien, könnte die Synthese der Resultate mehrerer Projekte helfen, den Beitrag verschiedener Methoden zum Erfolg eines Projektes quantitativ zu bewerten. Wir untersuchten die Durchfahrbarkeit einer solchen Meta-Analyse anhand der publizierten Resultate von 30 dokumentierten Freilassungsprojekten, die zwischen 1980 und 2000 in sechs europäischen Ländern durchgeführt wurden. Insgesamt wurden im Rahmen dieser Projekte mehr als 5500 gefangenschaftsaufgezogene Rauhfußhühner freigelassen. Die Zusammenstellung zeigte, daß nur für einige der Kriterien eine quantitative Analyse möglich war, da es in den publizierten Berichten oft an vergleichbarer Information mangelte. Für eine auf den Daten der Fallstudien basierende Meta-Analyse ist eine Vervollständigung der Dokumentationen notwendig. Um die Entwicklung und Anwendung effektiver Strategien zum Schutz gefährdeter Rauhfuflhuhnarten zu verbessern, schlagen wir einen Kriterien-Katalog vor, der bei der Berichterstattung aber Ansiedelungsprojekte verwendet werden sollte. Fri, 15 Mar 2024 09:31:54 +0100 Fri, 15 Mar 2024 09:34:44 +0100 https://popups.lib.uliege.be/2984-0317/index.php?id=2205 https://popups.lib.uliege.be/2984-0317/index.php?id=472 The Capercaillie has disappeared from the Belgian Ardennes at the beginning of the eighteenth century. Several reintroductions in Germany near the border in the late eighteenth and the early twentieth century have allowed some birds to reestablish small local populations which survived until 1933. The question arose as to the opportunity of a reintroduction in the Hautes Fagnes-Eifel Natural park. This problem is examined against the discussions conducted in Colmar in 1981 by two dozen specialists from France, Central and Northern Europe. The Capercaillie populations are on the decline in most parts of their european range since world war the second, and are near to become extinct in numerous traditional sites in Western and Central Europe, mainly in France, Germany and Bohemia. Factors affecting the population level are diseases, too high game-ungulates densities, atmospheric pollution (sharp rains), disturbance through touristic invasion, but all authors agree that the root of the problem is the development of modern sylviculture implying densification of the forest-roads network, spreading of phyto-sanitary products, and overall splitting and destruction of the habitat. This very sedentary bird needs indeed all its vital recquirements on a small area in mixed heterogenous forests with open wetter spaces for displaying and courting on the lek, dense shrub layer and plenty of preferred plants as food - blueberry shrub especially -, big old trees as roosting sites. Small population isolates disappear here and there. Numerous reintroduction programms have been conducted in the past 150 years. Very few succeeded, as in Scotland; most failed ! A special interest is granted to a raising experiment in progress in order to reintroduce the species in the Massif central in France, from where it disappeared two centuries ago; the young birds are released as soon as they have completed their post-juvenile moult, in a good heterogenous regenerated and planted forest; good attention is paid to the ontogeny of the behaviour and the adaptiveness of the birds to their new habitat. The aim is to produce enough birds to allow the building up of at least one reproductive social unit. Nevertheless, if the species is to be saved in those places from where it has not yet vanished, its vital habitat recquirements should be taken into consideration; plantations should be undertaken for long period through natural regeneration with small changes with time in natural ecological successions; clearings, borders should be multiplicated and diversity enhanced. Some experiments are in progress in Sweden, Switzerland and Black Forest of Germany, in order to achieve a compromise between conservation and economic recquirements. In France, forest management recommandations have been formulated by the national forestry service, since foresters are responsible for the structure and quality of the habitat: plant composition of the differents layers, importance of the clear-cuttings, length of the forest exploitation cycles. From all these considerations and experiments, it seems clear that conditions for a successful reintroduction of capercaillie in the Hautes-Fagnes are not prevailing at the present time. We need first to controll the public invasion and to improve the habitat suitability. But contacts with consultants and follow up of the Cevennes programme should be wellcommed. Fri, 26 Jan 2024 10:06:31 +0100 Fri, 26 Jan 2024 10:13:48 +0100 https://popups.lib.uliege.be/2984-0317/index.php?id=472