Resistance of forest songbirds to habitat perforation in a high-elevation conifer forest

Abstract

We examined responses of songbirds breeding in high-elevation Engelmann spruce – subalpine fir (Picea englemannii Parry ex Engelm. – Abies lasiocarpa (Hook.) Nutt.) forests to four perforation harvest patterns near Sicamous, British Columbia. Each treatment removed approximately 30% of the timber volume but varied the size of openings from 10-ha clearcuts to small gaps (<0.01 ha), where individual trees were removed. Abundance and diversity of breeding songbirds were monitored over a 4-year period, including 2 years each of pre- and post-harvest conditions. Two-thirds of the original songbird assemblage consisted of mature forest species that showed only modest changes in relative abundance following harvest. Two species showed significant responses to harvesting: golden-crowned kinglet (Regulus satrapa Lichtensteins) declined significantly postharvest, with the largest declines occurring in single-tree and 10-ha treatments; and dark-eyed junco (Junco hyemalis L.) responded positively to harvest. At high elevations, 30% volume removal allowed much of the songbird community to be accommodated immediately after harvest. Future research should address whether the apparent short-term accommodation of high-elevation birds persists across time and as more of the continuous forest cover is removed.

Short-term effects of group-selection harvesting on breeding birds in a northern hardwood forest

“…Leupin et al (2004) also found that intensive group selection maintains species diversity and the abundance of Golden-crowned Kinglets (Regulus satrapa), a mature forest associate, at reference levels, whereas they decline slightly under typical group selection. Others found that typical group selection alters the bird community relative to unharvested reference stands in the short-term in montane hardwood-conifer (Garrison et al, 2005), mixed pine (Pinus spp.…”

“…Two studies that compare the bird community before and immediately after harvest with intensive group selection, relative to unharvested reference stands, in the coniferous forests of northwestern North America found that the bird community changes little over the short-term (Chambers et al, 1999;Leupin et al, 2004). Leupin et al (2004) also found that intensive group selection maintains species diversity and the abundance of Golden-crowned Kinglets (Regulus satrapa), a mature forest associate, at reference levels, whereas they decline slightly under typical group selection.…”

Lessons learned from 12 years of ecological research on partial cuts in black spruce forests of northwestern Québec

“…Maintaining these cavity excavators is also important for many other cavity users that do not excavate cavities, but rely upon those created by woodpeckers for nesting or roosting purposes (Drapeau et al 2009). Persistence of suitable foraging and nesting habitat conditions for woodpeckers is thus critical for cavity-using communities often referred to as nest webs (sensu Leupin et al 2004), an important component of the functional diversity associated to deadwood in the boreal ecosystem. Breeding activity of keystone species such as woodpeckers is also an indication that partial cuts harbour appropriate deadwood pools for saproxylic insects, a main prey for woodpeckers (Nappi 2009).…”

Cavity and bark nesting bird response to partial cutting in Northern conifer forests

“…In our system, single trees and groups of trees were removed to create small to large gap openings (0.1-0.5 ha) that simulated small-scale disturbance events. Forest birds may exhibit resistance to light and heavy removal partial cutting using these types of procedures because harvested gaps appear similar to natural gap openings (Leupin et al, 2004;Waterhouse and Armleder, 2007;Drever et al, 2008). Birds associated with forest systems where gap dynamics are the primary natural disturbance regime will use the range of habitats found within these stands: closed canopy forest, natural gap openings (created by treefall gaps, streams, small wetlands), and forest edge (created at the interface between forest and gap openings).…”