Ectomycorrhizal fungi with hydrophobic mycelia and rhizomorphs dominate in young pine trees surviving experimental drought stress

Wildfires, wind storms, and pest outbreaks are the main large-scale disturbances of temperate and boreal forests, which often generate large amounts of deadwood in the landscape. Salvage and sanitation loggings (hereafter salvage logging) are usually practiced following such disturbance events and the generated deadwood is then extracted from the forest. Those practices affect a broad array of species, including fungi, lichens, invertebrates, and vertebrates that make use of deadwood either as habitat, food resource, foraging substrate, or as shelter. Woodpeckers, being a key group of forest birds dependent on deadwood, can be affected by salvage logging in two ways: (1) a reduction in the availability of food (i.e. removal of deadwood along with the saproxylic and predatory invertebrates that usually colonize dead or dying trees following forest disturbances) and (2) a decrease in potential nest sites due to the removal of dead trees. Therefore, we assessed the global effects of salvage logging on woodpecker abundance and reproduction by conducting a meta-analysis of published and unpublished data. We focused on comparing woodpeckers’ responses to forest disturbance in salvage-logged and unlogged sites. We considered different types of responses found in the literature, including abundance, occurrence, nest density, and breeding success. When analyzing the responses of woodpeckers, we also accounted for the potential effects of tree density, time since logging, elevation, latitude, and the continent.

Recent Findings
We found that both numbers and reproduction of woodpeckers were affected by salvage logging following a disturbance event. Apart from salvage logging, woodpecker responses were not significantly related to any other variables. This highlights that salvage logging can pose a substantial threat to woodpecker assemblages as well as secondary cavity-users dependent on them.

Summary
Salvage logging and related practices that affect deadwood availability should be carefully planned and preferably avoided entirely in areas important for woodpecker conservation. In managed forests, deadwood should be retained in sufficient quantities to avoid detrimental impacts on woodpeckers and on forest biodiversity in general.