Occupancy of the American Three-Toed Woodpecker in a Heavily-Managed Boreal Forest of Eastern Canada

Abstract

The southern extent of the boreal forest in North America has experienced intensive human disturbance in recent decades. Among these, forest harvesting leads to the substantial loss of late-successional stands that include key habitat attributes for several avian species. The American Three-toed Woodpecker, Picoides dorsalis, is associated with continuous old spruce forests in the eastern part of its range. In this study, we assessed the influence of habitat characteristics at different scales on the occupancy of American Three-toed Woodpecker in a heavily-managed boreal landscape of northeastern Canada, and we inferred species occupancy at the regional scale. We conducted 185 playback stations over two breeding seasons and modelled the occupancy of the species while taking into account the probability of detection. American Three-toed Woodpecker occupancy was lower in stands with large areas recently clear-cut, and higher in landscapes with large extents of old-growth forest dominated by black spruce. At the regional scale, areas with high probability of occupancy were scarce and mostly within protected areas. Habitat requirements of the American Three-toed Woodpecker during the breeding season, coupled with overall low occupancy rate in our study area, challenge its long-term sustainability in such heavily managed landscapes. Additionally, the scarcity of areas of high probability of occupancy in the region suggests that the ecological role of old forest outside protected areas could be compromised.

Are forest management practices to improve carbon balance compatible with maintaining bird diversity under climate change? A case study in Eastern North America

“…The conservation of unharvested areas, such as in the conservation management scenario, may mitigate the negative effect of climate and forest management-induced habitat loss for some bird species. Indeed, when the availability of suitable habitat is low, the fragmentation of the forest would decrease the probability of bird occurrence for certain species, such as Ovenbird (Seiurus aurocapilla) [108] and American Three-toed Woodpecker (Picoides dorsalis) [109]. This is particularly important with the historical [110] and predicted future decline [71] in mature forest in eastern Canada.…”

Change in altitudinal distribution of Newfoundland Gray-cheeked Thrush ( Catharus minimus minimus ) revealed through historical stop-level breeding bird survey data

“…The cause(s) of the sudden decline of Gray-cheeked Thrushes on Newfoundland are still being assessed. Habitat loss or degradation through timber harvesting have the potential to impact populations of forest birds (Thompson et al 1999, Lamarre and Tremblay 2021, Betts et al 2022), but the conifer scrub and montane forest favored by Gray-cheeked Thrushes on the island is seldom cut, and research also suggests that these thrushes are frequently associated with regenerating clearcuts (Whitaker et al 2015, McDermott 2021. Likewise, protected areas on the island, like national parks, have shown sharp reductions in numbers of Gray-cheeked Thrushes (Jacques Whitford Environment 1993).…”

Spatial segregation between Gray-cheeked Thrush and an introduced nest predator in a managed forest landscape

“…Several hypotheses have been suggested to explain this population collapse and apparently restricted contemporary distribution of Gray-cheeked Thrushes (Whitaker et al 2015). Timber harvesting has frequently been identified as having the potential to adversely affect forest bird populations (e.g., Thompson et al 1999, Lamarre andTremblay 2021), but the coastal conifer scrub and montane forests favored by Gray-cheeked Thrushes on Newfoundland are seldom cut. Research indicates that these thrushes are also associated with regenerating (i.e., 10-30 years post-harvest; see Table 1) clear-cuts (Whitaker et al 2015), but the extent of timber harvesting on Newfoundland has only decreased by about 50% since the early 1970s (McLaren andPollard 2009, Natural Resources Canada 2022).…”