Abstract
Standing deadwood is an important attribute of old-growth boreal forests and it provides essential microhabitats for deadwood-associated species. In managed boreal forests, short rotations tend to limit the amount and diversity of standing deadwood. This study evaluates if the anthropogenic supply of deadwood attributes through tree girdling or by providing nest boxes may favor deadwood-associated species. We studied the short-term response of saproxylic beetles, foraging woodpeckers, and secondary cavity users to snag and cavity supply in 50 to 70-year-old black spruce stands. In spring 2015, we girdled 8000 black spruce according to two spatial distributions (uniform and clustered), and we also installed 450 nest boxes of six different sizes at three distances from the forest edge. Using trunk window traps, we captured significantly more beetles in sites with girdled trees than in control sites in both 2015 and 2016. We also recorded a trend of a greater abundance of beetles in clusters of girdled trees than within uniformly distributed girdled trees. Trypodendron lineatum (Oliver) dominated beetle assemblages, representing 88.5% of all species in 2015 and 74.6% in 2016. The number of beetles captured was 7× higher in 2015 than in 2016. In contrast, we observed greater amounts of woodpecker foraging marks in fall 2016 than in either fall 2015 or spring 2016. Woodpeckers foraged significantly more in clusters of girdled trees than within uniformly distributed girdled trees. Woodpeckers’ foraging mark presence was positively associated with the proportion of recent cuts at 1 km around the study sites. Five Boreal Chickadee (Poecile hudsonicus Forster) pairs used nest boxes and occupied smaller box sizes that were located away from the forest edge. Our study showed that structural enrichment can be effective in rapidly attracting deadwood-associated species within managed forest stands.
Highlights
The overall landscape and age structure of eastern Canadian boreal forests have been altered by forest harvesting [1,2], thereby inducing changes in the amount and diversity of standing deadwood [3]
We observed no significant difference in the number of beetles captured per day between the uniform and clustered deadwood treatments, except for the Scolytinae in 2016
With the implementation of ecosystem-based management, forest managers should aim to limit the simplification of the internal structure of forest stands and the loss of certain types of deadwood [73]
Summary
The overall landscape and age structure of eastern Canadian boreal forests have been altered by forest harvesting [1,2], thereby inducing changes in the amount and diversity of standing deadwood [3]. The time elapsed between rotations does not allow the recovering of deadwood structures that are normally found in old-growth boreal forests [4]. Management and conservation targets implemented in recent decades have proven to be insufficient in preventing habitat losses below minimum ecological thresholds [5]. Given the similarities in forest-age structure and bird assemblages of Fennoscandian and northeastern Canadian boreal forests [8], it is important to implement management practices that will avoid such an outcome in Canada
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
