Comparing the effect of salvage logging on birds in the Mediterranean Basin and the Rocky Mountains: Common patterns, different conservation implications

Postfire salvage logging is currently a controversial issue because of the impact that the removal of snags has on ecosystem structure and function. Although it is a common practice worldwide, the absence of comparisons across regions hinders the development of broad generalizations. Here we compare bird response to postfire salvage logging in two regions with significant differences in landscape and bird communities, the Mediterranean Basin and the Rocky Mountains. The Mediterranean Basin features a landscape dominated by a mosaic of small-sized forests, farmland and shrublands, while the Rocky Mountains have large extensions of continuous forests. Bird conservation priorities are also different. In the Mediterranean Basin, priorities are oriented toward farmland birds, while they are oriented toward fire-specialists in the Rocky Mountains. We used databases describing bird species occurrence in burned forests from both regions and defined three groups of species based on their level of association with snags. We then compared the richness of each group among logged and unlogged sites, and also between regions. We found a higher proportion of species that showed some degree of association with snags in burned forests of the Rocky Mountains than in the Mediterranean Basin. Highly snag-associated birds from both regions showed a common negative response to salvage logging. Not snag-associated species increased in salvaged areas, but only in the Mediterranean Basin. The general negative effect of salvage logging on forest-dwelling species that are associated with trees or snags is a noteworthy pattern given the big differences between regions. Nevertheless, in the Mediterranean, some threatened farmland species benefit from logging, so the overall effect of the removal of snags appears to be relatively more detrimental to birds in the Rocky Mountains.