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Densities of breeding birds and changes in vegetation in an alaskan boreal forest following a massive disturbance by spruce beetles

Canadian Journal of Zoology

By:
, , and
DOI: 10.1139/cjz-79-9-1678

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Abstract

We examined bird and plant communities among forest stands with different levels of spruce mortality following a large outbreak of spruce beetles (Dendroctonus rufipennis (Kirby)) in the Copper River Basin, Alaska. Spruce beetles avoided stands with black spruce (Picea mariana) and selectively killed larger diameter white spruce (Picea glauca), thereby altering forest structure and increasing the dominance of black spruce in the region. Alders (Alnus sp.) and crowberry (Empetrum nigrum) were more abundant in areas with heavy spruce mortality, possibly a response to the death of overstory spruce. Grasses and herbaceous plants did not proliferate as has been recorded following outbreaks in more coastal Alaskan forests. Two species closely tied to coniferous habitats, the tree-nesting Ruby-crowned Kinglet (Regulus calendula) and the red squirrel (Tamiasciurus hudsonicus), a major nest predator, were less abundant in forest stands with high spruce mortality than in low-mortality stands. Understory-nesting birds as a group were more abundant in forest stands with high levels of spruce mortality, although the response of individual bird species to tree mortality was variable. Birds breeding in stands with high spruce mortality likely benefited reproductively from lower squirrel densities and a greater abundance of shrubs to conceal nests from predators.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Densities of breeding birds and changes in vegetation in an alaskan boreal forest following a massive disturbance by spruce beetles
Series title:
Canadian Journal of Zoology
DOI:
10.1139/cjz-79-9-1678
Volume
79
Issue:
9
Year Published:
2001
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Canadian Journal of Zoology
First page:
1678
Last page:
1690
Number of Pages:
13