|
|
|
SITE NAME
|
Varanger peninsula, Norway
|
|
| Contact
details (phone/fax//e-mail//address): |
| // Rolf.ims@ib.uit.no // Dept of Biology, Univ. of Tromso, NO-9037 Tromso, Norway |
|
PROJECT DETAILS
|
|
Start of survey:
|
End
of survey:
|
Team
size:
|
|
|
|
|
|
WEATHER CONDITIONS
|
|
|
|
|
|
|
|
|
|
| Date of ice-break
on rivers: |
|
|
| Date of final loss
of snow: |
|
|
BIOTIC CONDITIONS
|
| Rodents abundance evaluation: |
high |
|
Breeding conditions:
|
| As it could be expected there was also a sharp increase in numbers of specialist lemming predators, such as Snowy Owls and Ermines. Long-tailed Skuas bred at a high density of ca. 1.0 pairs/km2, and 5 nests of Rough-legged Buzzards were found in the study area. There were 4 established pairs of Arctic Foxes in the spring and 3 of them bred. |
|
|
Rodent dynamics:
|
The focus of the ecological investigation on the Varanger Peninsula is on food web dynamics, in particular, on the relation between small rodent prey and their predators. The most important observation at the end of March 2007 was a high number of Norwegian Lemming's tracks. While only one track was observed on our transects in March 2006, there were now several 100s. Lemmings were already quite numerous in October 2006, but may have become even more abundant later in the winter due to breeding under the snow. Of course many lemmings on the snow surface may reflect mass occurrence under the snow blanket. However, an alternative explanation could has been that the conditions for some reasons had become so bad that lemmings had started to migrate. We dug a number of snow pits (some of them 3 meter deep) to investigate the properties of the snow pack. There were several heavy layers of crust snow, but little or no ice near the ground.
In 2007 the populations of Norwegian Lemming, Grey-sided Vole and Tundra Vole had a distinct peak of the 5-year cycle.
|
|
Rodent species recorded:
|
| Latin | Abundance |
|---|
| Lemmus lemmus | abundant |
| Microtus oeconomus | abundant |
| Clethrionomys rufocannus | abundant |
|
|
|
Summary
of fauna studies: |
|
|