No abstract

Standing dead trees may be a limited resource for woodpeckers in managed forests, especially for species that rely on dead wood for their nest or roost cavity, and as foraging sites. Effective conservation strategies for woodpeckers require a detailed knowledge of species' responses to dead wood availability. To investigate the importance of standing dead wood (snags) for the abundance and nest-site use of the great spotted woodpecker Dendrocopos major and middle spotted woodpecker Leiopicus medius in mature riverine forests, we compared the responses of birds between two periods-before mass mortality, and during a pulse in standing dead trees. The density of standing dead trees available for cavity excavation by the great spotted woodpecker and the middle spotted woodpecker increased significantly during the study period: 37-fold and 4-fold, respectively. Temporal trends in the abundance of both woodpecker species from 2000 to 2015 were not significant. Great spotted woodpeckers were significantly more likely to use dead trees and places with wounds in species other than oak and ash during the outbreak period than in the pre-outbreak period. Middle spotted woodpeckers were significantly less likely to excavate cavities in tree species other than oak and ash in the outbreak period, but dead trees were more likely selected. An interspecific comparison suggests that the probability of a nest-hole having been excavated by a middle spotted woodpecker increased with a nest-hole sited in ash, in a dead tree, in a limb/branch, and decreased with 123Biodivers Conserv (2018) 27:123-145 https://doi.org/10.1007/s10531-017-1425-6 a nest-hole in a closed forest. These findings suggest that woodpecker species, especially weak excavators, may benefit from an increase in dead wood availability leading to nest niche shifts into more favorable substrates for cavity excavation. However, a strong increase in dead wood availability does not modify the general pattern of niche partitioning between great spotted and middle spotted woodpeckers. Conservation plans for the specialized middle spotted woodpecker must consider the preference for dead and decaying trees. The decreasing number of large ashes and oaks, and the lack of natural regeneration of the latter species, may negatively affect the middle spotted woodpecker in the future.

The main goals of this study were to investigate the relationships between densities of the breeding population of the middle spotted woodpecker Dendrocopos medius obtained on 19 large-scale plots, and the share of different habitats and age of forest stands. An average crude density based on an area defined arbitrarily by observers was 0.66±0.43 territories/10 ha, while the ecological density based on an area including habitats potentially used by organisms reached 1.09±0.64 territories/10 ha. Stepwise multiple regression indicated that the crude density was negatively affected by the share of coniferous forest thereby explaining 50% of variation. The ecological density was negatively correlated with the percentage of young deciduous stands (0-40 years old). This variable explained 36% of the total variation. These results suggest that on the level of macrohabitat analysis, the share of unsuitable forest stands seem to play a major role in determining the density of the middle spotted woodpecker.

<em>Microstoma protracta</em> (Fr.) Kanouse is a strictly protected species in Poland, which is also present on the red list with the category R (rare). In Poland, there are five known localities for the species, including four historical sites discovered at the beginning of the twentieth century and one contemporary site discovered at the end of the twentieth century. In this paper, we present two new localities for <em>M. protracta</em>, discovered in April 2006 in Czeszewo (Wielkopolska Lowland, Jarocin Forest District) and in April 2017 in Krakow-Tyniec (Krakow-Częstochowa Upland, Myślenice Forest District). Sequences of the nuclear ribosomal DNA internal transcribed spacer regions of sporocarps from contemporary localities have been deposited in the GenBank database. This is the first record of the DNA barcode for this species. According to Criterion D of the IUCN recommendations, it has been suggested that <em>M. protracta</em> should be considered as a critically endangered species (CR: D) in Poland.