title: Factors Affecting Diet Variation in the Pyrenean Rock Ptarmigan (Lagopus muta pyrenaica): Conservation Implications.
abstract: 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.
authors: Instituto Pirenaico de Ecología (CSIC), Jaca, Spain.
authors: Ricardo
authors: R
authors: García-González
authors: Plant Biology and Ecology Department, Basque Country University, Bilbao, Spain.
authors: Arantza
authors: A
authors: Aldezabal
authors: Plant Biology and Ecology Department, Basque Country University, Bilbao, Spain.
authors: Nere Amaia
authors: NA
authors: Laskurain
authors: Department of Animal Production, Division of Wildlife, Faculty of Life Sciences and Engineering, University of Lleida, Lleida, Spain.|Division of Conservation Biology, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland.
authors: Antoni
authors: A
authors: Margalida
authors: Office National de la Chasse et de la Faune Sauvage, Prades, France.
authors: Claude
authors: C
authors: Novoa
mesh_terms: D000531:Altitude; D000818:Animals; D003247:Conservation of Natural Resources; D004032:Diet; D017753:Ecosystem; D029791:Ericaceae / Q000254:growth & development; D005243:Feces / Q000737:chemistry; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D005602:France; D046094:Galliformes / Q000502:physiology*; D060434:Herbivory / Q000502:physiology*; D008297:Male; D029793:Rhododendron / Q000254:growth & development; D027824:Rosaceae / Q000254:growth & development; D032108:Salix / Q000254:growth & development; D012621:Seasons; D012914:Snow; D013030:Spain