| |
| Title: |
Densities
of breeding birds and changes in vegetation in an Alaskan boreal forest
following a massive disturbance by spruce beetles |
| 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 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. |
| Keywords: |
Spruce beetles, Dendroctonus rufipennis, bird communities,
forest disturbance, Copper River Basin, plant communities |
| Status: |
Complete; see Canadian Journal of Zoology 79:1678-1690 for
full summary. |
| Duration: |
1997-1998, field work |
| Location: |
Copper River Basin, Alaska |
| Region: |
Central Alaska |
| Cooperators: |
USGS Alaska Biological Science Center; Wrangell-St. Elias
National Park and Preserve; Bureau of Land Management; Alaska State Department
of Natural Resources; University of Alaska, Fairbanks; Chitina Native Corporation;
Ahtna Native Corporation |
| Contacts: |
- Steve Matsuoka
- USGS-Alaska Science Center
- 1011 East Tudor Road, Anchorage, AK 99503 USA
- 907-786-3672
- steve_matsuoka@usgs.gov
|
|
- Colleen Handel
- USGS-Alaska Science Center
- 1011 East Tudor Road, Anchorage, AK 99503 USA
- 907-786-3418
- colleen_handel@usgs.gov
|
