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Title:
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Factors affecting diet variation in the Pyrenean rock ptarmigan (Lagopus muta pyrenaica): Conservation implications
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Author:
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García González, Ricardo; Aldezabal, Arantza; Amaia Laskurain, Nere; Margalida, Antoni; Novoa, Claude
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Notes:
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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.
This work was carried out with a cooperation agreement between the Office National de la Chasse et de la Faune Sauvage (France) and the Consejo Superior de Investigaciones Científicas (Spain). Additional funds were provided by RTA (Agricultural Technologies and Resources) 2005- 00160-C02-02, MAM 2484/2002 Spanish projects and LEDDRA FW7 ENV.2009.2.1.3.2 Desertification process and land degradation (SICA-EU). AM was supported by a Ramón y Cajal research contract from the Ministry of Economy and Competitiveness (RYC- 2012-11867). |
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Rights:
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cc-by (c) García González, Ricardo et al., 2016
http://creativecommons.org/licenses/by/3.0/es/
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Document type:
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article
publishedVersion |
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Published by:
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Public Library of Science
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