Studying intraspecific spatiotemporal variation in vital rates among populations over a range of environmental conditions is essential to reveal intrinsic and extrinsic factors affecting population dynamics. Mammal populations living at higher elevations often have higher adult survival, shorter breeding seasons, and lower reproductive output per season than at lower elevations. We studied dynamics of a Eurasian red squirrel (Sciurus vulgaris) population in high-elevation, mountain pine (Pinus mugo) forest with extreme winters, in the Central Italian Alps, and compared vital rates with populations in more productive habitats at lower elevations. Average density was 0.14 +/- 0.07 squirrels ha–1 (range 0.07–0.30 ha–1), and numbers typically increased in summer–autumn as a result of seasonal reproduction and immigration. Mean persistence time was only 12.5 months, and there was a nearly complete population turnover in only two years. Local survival and recruitment rate were correlated with seasonal population growth rate, and partial effect of survival explained 80% of variation in growth rate. While reproductive rate in mountain pine habitat was more similar than in more productive habitats at lower elevations, density and autumn–winter survival were much lower. Thus, red squirrels did not show the adaptations observed in several other mammal species, but might invest heavily in early reproduction to compensate for short life expectancy.

Living on the edge: can red squirrels (Sciurus vulgaris) persist in extreme high-elevation habitats?

WAUTERS, LUCAS ARMAND;PREATONI, DAMIANO;TOSI, GUIDO;MARTINOLI, ADRIANO
2010

Abstract

Studying intraspecific spatiotemporal variation in vital rates among populations over a range of environmental conditions is essential to reveal intrinsic and extrinsic factors affecting population dynamics. Mammal populations living at higher elevations often have higher adult survival, shorter breeding seasons, and lower reproductive output per season than at lower elevations. We studied dynamics of a Eurasian red squirrel (Sciurus vulgaris) population in high-elevation, mountain pine (Pinus mugo) forest with extreme winters, in the Central Italian Alps, and compared vital rates with populations in more productive habitats at lower elevations. Average density was 0.14 +/- 0.07 squirrels ha–1 (range 0.07–0.30 ha–1), and numbers typically increased in summer–autumn as a result of seasonal reproduction and immigration. Mean persistence time was only 12.5 months, and there was a nearly complete population turnover in only two years. Local survival and recruitment rate were correlated with seasonal population growth rate, and partial effect of survival explained 80% of variation in growth rate. While reproductive rate in mountain pine habitat was more similar than in more productive habitats at lower elevations, density and autumn–winter survival were much lower. Thus, red squirrels did not show the adaptations observed in several other mammal species, but might invest heavily in early reproduction to compensate for short life expectancy.
ARCTIC ANTARCTIC AND ALPINE RESEARCH
File in questo prodotto:
File Dimensione Formato  
Artic_Antarctic_and_Alpine_Research_42_2010.pdf

accesso aperto

Tipologia: Documento in Post-print
Licenza: DRM non definito
Dimensione 349.74 kB
Formato Adobe PDF
349.74 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11383/1717296
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 10
  • ???jsp.display-item.citation.isi??? 10
social impact