title: Influence of Snowmelt Timing on the Diet Quality of Pyrenean Rock Ptarmigan (Lagopus muta pyrenaica): Implications for Reproductive Success.
abstract: 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.
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: D000818:Animals; D017753:Ecosystem; D005060:Europe; D005260:Female; D046094:Galliformes / Q000502:physiology*; D006801:Humans; D008297:Male; D008954:Models, Biological; D012098:Reproduction / Q000502:physiology*