Détail de la notice
Titre du Document
Functional and numerical responses of four lemming predators in high arctic greenland
Auteur(s)
GILG Olivier ; SITTLER Benoit ; SABARD Brigitte ; ...
Résumé
The high-arctic tundra ecosystem has the world's simplest vertebrate predator-prey community, with only four predators preying upon one rodent species, the collared lemming (Dicrostonyx groenlandicus). We document the functional and numerical responses of all the four predators in NE Greenland. Using these data, we assess the impact of predation on the dynamics of the collared lemming with a 4 yr cycle and > 100-fold difference between maximum and minimum densities. All predator species feed mostly ( >90%) on lemmings when lemming density is > 1 ha -', but the shapes of the predators' responses vary greatly. The snowy owl (Nyctea scandiaca) is present and breeds only when lemming densities at snowmelt are >2 ha-1, giving rise to a step-like numerical response. The long-tailed skua (Slercorarius longicaudus) has a type III functional response and shifts from alternate food (mainly berries and insects) to lemmings with increasing lemming density. The skua surpasses all the other predators in summer by its total response. The type III functional response of the Arctic fox (Alopex lagopus) starts to increase at much lower lemming densities than the responses of the avian predators, but it has only a weak numerical response. Finally, the stoat (Mustela erminea) is the most specialized predator and the only one with a clearly delayed numerical response. According to heir specific functional and numerical responses, each predator plays a key role at some point of the lemming c
Editeur
Blackwell
Identifiant
ISSN : 0030-1299 CODEN : OIKSAA
Source
Oikos A. 2006, vol. 113, n° 2, pp. 193-216 [24 pages] [bibl. : 3 p.1/4]
Langue
Anglais
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