39 research outputs found
Influence of Snowmelt Timing on the Diet Quality of Pyrenean Rock Ptarmigan (Lagopus muta pyrenaica): Implications for Reproductive Success
The Pyrenean rock ptarmigan (Lagopus muta pyrenaica) is the southernmost subspecies of the species in Europe and is considered threatened as a consequence of changes in landscape, human pressure, climate change, and low genetic diversity. Previous studies have shown a relationship between the date of snowmelt and reproductive success in the Pyrenean ptarmigan. It is well established that birds laying early in the breeding season have higher reproductive success, but the specific mechanism for this relationship is debated.
We present an explicative model of the relationship between snowmelt date and breeding success mediated by food quality for grouse in alpine environments. From microhistological analyses of 121 faecal samples collected during three years in the Canigou Massif (Eastern Pyrenees), and the assessment of the chemical composition of the main dietary components, we estimated the potential quality of individual diets. Potential dietary quality was correlated
with free-urate faecal N, a proxy of the digestible protein content ingested by
ptarmigan, and both were correlated with phenological stage of consumed plants, which in turn depends on snowmelt date. Our findings suggest that the average snowmelt date is subject to a strong interannual variability influencing laying date. In years of early snowmelt, hens benefit from a longer period of high quality food resources potentially leading to a higher breeding success. On the contrary, in years of late snowmelt, hens begin their breeding period in poorer nutrient condition because the peaks of protein content of their main
food items are delayed with respect to laying date, hence reducing breeding performance. We discuss the possible mismatch between breeding and snowmelt timing
Partage de l'espace entre le LagopÚde. Lagopus mutus pyrenaicus et la Perdrix grise Perdrix perdrix hispaniensis dans le Massif du Carlit (Pyrénées Orientales) en fonction de l'altitude et de l'exposition
On the Carlit Mountain range, eastern Pyrénées, the Pyrenean Ptarmigan Lagopus mutus pyrenaicus and the Spanish subspecies of the Partridge Perdrix perdrix hispaniensis are sympatric. The partitioning of space between these two Gallif ormes was studied throughout the whole yearly cycle, between 1980 and 1985.
Both species can overlap altitudinally, ptarmigans ranging from 1 900 m to 2 899 m, and partridges from 1 400 to 2 499 m. However, seasonal altitudinal changes do occur (Fig. 2). Whereas ptarmigans stay most of the time at higher altitudes and display minor altitudinal shifts, partridges are found at lower altitudes in winter and spring, moving higher only during the summer â a period during which the ranges of both species do overlap (Fig. 3).
Furthermore, the two species differ greatly in their preferences for definite exposures : partridges always prefer southern or south-western slopes, while ptarmigans favor northern or eastern exposures (Fig. 4).Les donnĂ©es prĂ©sentĂ©es rĂ©vĂšlent des diffĂ©rences dans lâutilisation des altitudes et des expositions par deux espĂšces dâoiseaux montagnards sympatriques : la Perdrix grise de montagne et le LagopĂšde alpin. Les rĂ©partitions saisonniĂšres diffĂšrent surtout par lâaltitude pour la Perdrix grise et par lâexposition pour le LagopĂšde. Ainsi les perdrix tendent Ă frĂ©quenter des altitudes plus basses en hiver et au printemps, alors que les lagopĂšdes utilisent surtout des altitudes hautes tout au long de lâannĂ©e. Dâautre part, les expositions au sud et au sud-ouest fournissent la majoritĂ© des observations de Perdrix, quelle que soit la saison. La sĂ©paration spatiale entre les deux espĂšces est bien marquĂ©e en Ă©tĂ© et en automne, lorsque des expositions distinctes sont choisies, ainsi quâau printemps quand les rĂ©partitions altitudinales sont bien diffĂ©renciĂ©es.
Lâanalyse des donnĂ©es permet ainsi de dĂ©finir une mobilitĂ© spatiale de type horizontal pour les lagopĂšdes et de type vertical pour les perdrix. Les implications sur la compĂ©tition entre ces deux espĂšces sont discutĂ©es.Gonzalez Georges, Novoa Claude. Partage de l'espace entre le LagopĂšde. Lagopus mutus pyrenaicus et la Perdrix grise Perdrix perdrix hispaniensis dans le Massif du Carlit (PyrĂ©nĂ©es Orientales) en fonction de l'altitude et de l'exposition. In: Revue d'Ăcologie (La Terre et La Vie), tome 44, n°4, 1989. pp. 347-360
Le régime alimentaire automnal de la perdrix grise (Perdix Perdix Hispaniensis) dans les Pyrénées-orientales
18 påginas, 2 figuras, 4 tablas.[EN]: We analysed the crop contents of 94 Pyrenean grey Partridges Perdix Perdix hispaniensis collected in the eastern Pyrenees from 1980 to 1996. Birds were shot by hunters in September-November over a large range of altitudes (1000-2400 m.).[FR]: Nous avons analysé 94 jabots de perdrix grise (Perdix Perdix hispaniensis) collectés entre q980 et 1996 dans les Pyrénées-Orientales. Ces jabots provienment d'oiseaux tirés en période de chasse (septembre-novembre) à des altitudes comprise entre 1000 et 2400m.Peer reviewe
Le régime alimentaire automnal de la Perdrix grise (Perdix perdix hispaniensis) dans les Pyrénées-Orientales
We analysed the crop contents of 94 Pyrenean Grey Partridges Perdix perdix hispaniensis collected in the eastern Pyrenees from 1980 to 1996. Birds were shot by hunters in September-November over a large range of altitudes (1 000-2 400 m). The various food items were classified into six categories (grasses, forbs, seeds, berries, tubers-bulbs and animal prey), dried in an oven and weighed. Preparations of epidermal cells were made to identify grasses and forbs.
Vegetable matter accounted for 79 % of dry weight. Grasses and forbs, in spite of high frequencies of occurrence (respectively 72 % and 84 %), contributed least to total dry weight. Seeds and animal prey, mainly Orthoptera, were the most important autumn foods, comprising respectively 30 % and 21 % of the total dry weight. There was neither age-related nor altitude-related difference in the foods eaten, but the contribution of green matter was higher in late autumn (> 20.X) than in early autumn.
Seventy five plant species were identified. The identification of epidermal cells of grasses by microscopic analysis showed a high frequency of the following three species : Poa alpina, Festuca rubra and F. ovina. At least 29 % (20/70) of vegetable species eaten by partridges were characteristic of pastures subjected to a high grazing pressure.
In terms of habitat selection, these features suggest that in late autumn Grey Partridges sought mainly areas intensively grazed by cattle. In the mountainous habitat of the Grey Partridge, like shrublands of broom (Cytisus purgans), the floristic diversity is generally poor. Thus, grazing could improve both the diversity of flora and the level of nitrogen content of vegetable foods.Nous avons analysĂ© 94 jabots de Perdrix grise (Perdix perdix hispaniensis) collectĂ©s entre 1980 et 1996 dans les PyrĂ©nĂ©es-Orientales. Ces jabots proviennent dâoiseaux tirĂ©s en pĂ©riode de chasse (septembre-novembre) Ă des altitudes comprises entre 1 000 et 2 400 m. Pour chaque jabot, les diffĂ©rents fragments ont Ă©tĂ© classĂ©s en six catĂ©gories (graminĂ©es, dicotylĂ©dones herbacĂ©es, graines, fruits charnus, tubercules-bulbes et nourriture animale), sĂ©chĂ©s Ă lâĂ©tuve et pesĂ©s Ă 0,001 g prĂšs. Un examen des tissus Ă©pidermiques au microscope a permis dâidentifier la plupart des graminĂ©es et des dicotylĂ©dones herbacĂ©es.
La nourriture vĂ©gĂ©tale a reprĂ©sentĂ© 79 % du poids sec total des jabots. Les graines et la nourriture animale, principalement les orthoptĂšres, ont Ă©tĂ© les principaux aliments consom- mĂ©s Ă lâautomne, reprĂ©sentant respectivement 30 % et 21 % du poids sec total. La contribution de la nourriture verte a augmentĂ© significativement aprĂšs le 20 octobre, prĂ©figurant ainsi le rĂ©gime alimentaire hivernal. Les prĂ©parations de tissus Ă©pidermiques, rĂ©alisĂ©es sur un Ă©chantillon de 55 limbes de graminĂ©es, ont montrĂ© la prĂ©dominance des 3 espĂšces suivantes : Poa alpina, Festuca rubra et F. ovina. La classification des espĂšces vĂ©gĂ©tales trouvĂ©es dans les jabots en fonction du niveau dâexploitation du milieu (pression pastorale et fauche) indique que 29 % (20/70) des espĂšces consommĂ©es sont caractĂ©ristiques dâun fort niveau de pression pastorale. Du point de vue de la sĂ©lection de lâhabitat, ces rĂ©sultats suggĂšrent quâĂ lâautomne les Perdrix grises recherchent des zones intensivement pĂąturĂ©es par le bĂ©tail. Dans les PyrĂ©nĂ©es-Orientales, la richesse floristique de certains habitats de la Perdrix grise, comme les landes Ă GenĂȘt purgatif (Cytisus purgans), est gĂ©nĂ©ralement faible. Dans ces conditions, le pastoralisme pourrait amĂ©liorer Ă la fois la diversitĂ© floristique ainsi que la qualitĂ© (protĂ©ines brutes) de la nourriture vĂ©gĂ©tale des Perdrix grises.Novoa Claude, Garcia Gonzalez Ricardo, Aldezabal Arantza. Le rĂ©gime alimentaire automnal de la Perdrix grise (Perdix perdix hispaniensis) dans les PyrĂ©nĂ©es-Orientales. In: Revue d'Ăcologie (La Terre et La Vie), tome 54, n°2, 1999. pp. 149-166
Autumn diet of the Grey Partridge (Perdix perdix hispaniensis) in eastern Pyrenees
Nous avons analysé 94 jabots de Perdrix grise (Perdix perdix hispaniensis) collectés entre 1980 et 1996 dans les Pyrénées-Orientales. Ces jabots proviennent d'oiseaux tirés en période de chasse (septembre-novembre) à des altitudes
comprises entre 1 000 et 2 400 m. Pour chaque jabot, les différents fragments ont été classés en six catégories (graminées, dicotylédones herbacées, graines, fruits charnus, tubercules-bulbes et nourriture animale), séchés à l'étuve et pesés à 0,001 g prÚs. Un examen des tissus épidermiques
au microscope a permis d'identifier la plupart des graminées et des dicotylédones herbacées. La nourriture végétale a représenté 79 % du poids sec total des jabots. Les graines et la nourriture animale, principalement les orthoptÚres, ont été les principaux aliments consommés à l'automne,
représentant respectivement 30 % et 21% du poids sec total. La contribution de la nourriture verte a augmenté significativement aprÚs le 20 octobre, préfigurant ainsi le régime alimentaire hivemal. Les préparations de tissus épidermiques, réalisées sur un échantillon de 55 limbes de
graminées, ont montré la prédominance des 3 espÚces suivantes : Poa alpina, Festuca rubra et F. ovina. La classification des espÚces végétales trouvées dans les jabots en fonction du niveau d'exploitation du milieu (pression pastorale et fauche) indique que 29 % (20/70) des espÚces
consommées sont caractéristiques d'un fort niveau de pression pastorale. Du point de vue de la sélection de l'habitat, ces résultats suggÚrent qu'à l'automne les Perdrix grises recherchent des zones intensivement pùturées par le bétail. Dans les Pyrénées-Orientales, la richesse floristique
de certains habitats de la Perdrix grise, comme les landes Ă GenĂȘt purgatif (Cytisus purgans), est gĂ©nĂ©ralement faible. Dans ces conditions, le pastoralisme pourrait amĂ©liorer Ă la fois la diversitĂ© floristique ainsi que la qualitĂ© (protĂ©ines brutes) de la nourriture vĂ©gĂ©tale des Perdrix
grises
Quantifying genetic distance between wild and captive strains of the grey partridge Perdix perdix in France: conservation implications
International audienc
Factors Affecting Diet Variation in the Pyrenean Rock Ptarmigan (Lagopus muta pyrenaica): Conservation Implications
The Pyrenean rock ptarmigan (Lagopus muta pyrenaica) lives at one of the southernmost limits of the ptarmigan range. Their small population sizes and the impacts of global changes are limiting factors in the conservation of this threatened subspecies. An effective conservation policy requires precise basic knowledge of a species' food and habitat requirements, information that is practically non-existent for this Pyrenean population. Here, we describe the diet of a ptarmigan population in the Eastern Pyrenees, the environmental factors
influencing its variability and the relationship between diet floristic composition and quality. Diet composition was determined by microhistological analysis of faeces and diet quality was estimated from free-urate faecal N content. Our results show that grouse diet is based mainly on arctic-alpine shrubs of the Ericaceae family, as well as dwarf willows (Salix spp.) and Dryas octopetala. The most frequently consumed plant species was Rhododendron ferrugineum, but its abundance in the diet was negatively related to the diet nitrogen content. Conversely, the abundance of Salix spp., grass leaves and arthropods increased
the nitrogen content of the diet. Seasonality associated with snow-melting contributed the most to variability in the Pyrenean ptarmigan diet, differentiating winter from spring/summer diets. The latter was characterised by a high consumption of dwarf willows, flowers, arthropods and tender forb leaves. Geographic area and sex-age class influenced diet variability to a lesser extent. Current temperature increases in the Pyrenees due to global warming
may reduce the persistence and surface area of snow-packs where preferred plants for rock ptarmigan usually grow, thus reducing food availability. The high consumption of Rh. ferrugineum characterised the diet of the Pyrenean population. Given the toxicity of this plant for most herbivores, its potential negative effect on Pyrenean ptarmigan populations should be evaluated