Lemming predators on the Siberian tundra

• In the Eurasian Arctic, the most common lemming species are the Siberian lemming (Lemmus sibiricus) and the collared lemming (Dicrostonyx torquatus). Lemmings constitute the main food item for 5 common predators in the area: arctic fox; snowy owl; rough-legged buzzard; long-tailed skua; and pomarine skua. Hence, these predators form a foraging guild. We have studied factors influencing the structure of this guild. When comparing cooccurrence of the predators between 17 sites across Siberia, there were positive associations between the snowy owl and the two skuas, and a negative association between snowy owl and rough-legged buzzard. There was also a large variation in local population density among the predators, conceivably, due to the risk of intra-guild predation as well as the variation in food supply. There were significant relationships between lemming abundance and the abundance of each predator. An analysis of the predatory response by the arctic fox indicated a response pattern similar to that of a delayed numerical response to lemming abundance. For this and other reasons, we propose that the arctic fox is a resident specialist predator on microtine rodents. Further, the birds appeared to be nomadic specialist predators with, perhaps, one exception, the rough-legged buzzard.

Ämnesord

NATURVETENSKAP  -- Biologi -- Zoologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Zoology (hsv//eng)

Nyckelord

ARCTIC FOX POPULATION

RODENT POPULATIONS

FIELD EXPERIMENTS

SOUTHERN

SWEDEN

NEST SITES

DYNAMICS

DENSITY

CYCLES

FOOD

FLUCTUATIONS

zoologi

Zoology

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