Key Elements of the White-Backed Woodpecker’s (Dendrocopos leucotos lilfordi) Habitat in Its European South-Western Limits

In the last decade, the population of the white-backed woodpecker (Dendrocopos leucotos lilfordi) (WBW) in Navarre has been reduced mainly due to the loss of suitable habitat for this species from intensive forest management, leading almost to its extinction. This study aimed to identify the key structural elements of breeding habitats of the WBW and analyze their effect on the composition of the saproxylic fungi community within the habitats. In the Special Area of Conservation, namely Quinto Real in Navarre, 20 circular plots (500 m2) and 10 transects (150–300 m) were located inside and outside WBW territories. Within each sample plot, forest structure, deadwood, microhabitats, regeneration, and saproxylic fungi community were studied. The results showed that the key elements in the WBW territories were high trees, high diversity of deadwood (with a high presence of big and late-decay deadwood), high snag volume, and high microhabitat diversity. Although the past management is also evident in the variability of some of those characteristics, this species is well adapted to different structural and compositional conditions of the territory. The saproxylic fungi community was richer among the WBW territories, and in those areas, the presence of Fomes fomentarius was high, compared to non-WBW territories where it was not present. In conclusion, to maintain and protect the studied population, it is necessary to implement sustainable management that guarantees the conservation of the key elements for the WBW territories (structural heterogeneity and high deadwood diversity) in order to increase the suitability of the habitat for WBWs.We gratefully acknowledge the financial support from the Departments of Environment and Education of the Basque Government and from the Department of Environment of the County Council of Biscay