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 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.

Differences in bird communities in postfire silvicultural practices stands within pine forest of South Korea

“…Also, the differences in a mean number of observed bird species and individuals, bird species diversity index (H 0 , Shannon and Weaver 1949), and Simpson's diversity index (D s , Simpson 1949) among study stands were analyzed by simple one-way ANOVA. When the variables were significantly different among stands (P \ 0.05), we used Bonferroni multiple-comparison test to identify specific mean differences (Matsuoka et al 2001).…”

Impact of Phytophthora-dieback on birds in Banksia woodlands in south west Western Australia

“…overstorey. No studies involving disease-induced loss of overstory are available for comparison, but similar studies on forest insect attack have indicated the importance of canopy, with canopy-dependent species declining due to the loss of habitat (Matsuoka et al, 2001;Rabenold et al, 1998;Tingley et al, 2002).…”

Effects of spruce beetle infestations on berry productivity on the Kenai Peninsula, Alaska

“…On the Kenai Peninsula as many as 14 species of mammals and 30 species of birds commonly feed on berries (Martin et al, 1951;Erhlich et al, 1988). The spruce beetle infestation changed the forest canopy structure and directly affected habitat use by many forest birds (Lance and Howell, 2000;Matsuoka et al, 2001). Changes in understory vegetation as a result of decreased overstory competition affected habitat used by small mammals (Williams, 1999;Matsuoka et al, 2001;Lance et al, 2006).…”

“…The spruce beetle infestation changed the forest canopy structure and directly affected habitat use by many forest birds (Lance and Howell, 2000;Matsuoka et al, 2001). Changes in understory vegetation as a result of decreased overstory competition affected habitat used by small mammals (Williams, 1999;Matsuoka et al, 2001;Lance et al, 2006). Similarly, changes in browse availability altered how www.elsevier.com/locate/foreco Forest Ecology and Management 227 (2006) [247][248][249][250][251][252][253][254][255][256] moose used this landscape (Collins and Schwartz, 1998).…”