Habitat selection by Cantabrian capercaillie Tetrao urogallus cantabricus at the edge of the species' distribution

Abstract

We studied the patterns of habitat availability and use by the Cantabrian capercaillie Tetrao urogallus cantabricus, an isolated and endangered population at the southwestern edge of the species distribution. We combined field surveys and GIS analyses to show that this population differs from its conifer-specialist conspecifics in that it inhabits beech Fagus sylvatica and oak Quercus petraea forests, without specialisation as regards the tree species as long as enough forest cover remains. The habitat of Cantabrian capercaillie is highly fragmented, and smaller forest patches have been abandoned during the last few decades; the display areas that remain occupied are now located farther from forest edges. Lower tree density and more widespread distribution of bilberry Vaccinium myrtillus characterised the occupied display grounds. However, even abandoned areas showed tree densities well within the optimum range for capercaillie and bilberry in other populations, a result that should be taken into account before any habitat management action is considered. We found that some non-forested habitats were also used by capercaillie, especially during the autumn and winter. We suggest that the protection of Cantabrian capercaillie should be tightly coupled with an effective, strict protection of the few remaining large forest fragments in the range, and that information about nesting and brood rearing habitat should be obtained. Conditions for understory development should be favoured, preventing overgrazing by ungulates. The natural, non-forested matrix should also be considered in management plans, as a direct source of food and shelter and an important feature determining connectivity among patches.

The Mediterranean Quercus pyrenaica oak forest: a new habitat for the Capercaillie?

“…This is particularly important because the potential habitat for this endangered subspecies could thus be greatly increased, as Q. pyrenaica forests are highly represented with[100,000 ha at the southern slope of the Cantabrian Mountains (Gil-Sánchez and Torre-Antón 2007). Additionally, despite the idea that Q. pyrenaica forests are not considered as suitable habitat (Quevedo et al 2006b), and neither are included in the recovery plans for the Cantabrian Capercaillie, our study highlights the need to take into account these forests for the conservation of this subspecies. Nonetheless, the role of the pine plantations for Capercaillie in the study area should be further assessed.…”

“…In these forests, holly Ilex aquifolium provides a key, evergreen winter food resource for Cantabrian Capercaillie (Storch 2001;Blanco-Fontao et al 2010), whereas it relies on bilberry in summerautumn (Blanco-Fontao et al 2010). Previous studies showed, however, a negative selection to Quercus pyrenaica forests by Cantabrian Capercaillie at the northern slope of the Cantabrian range (Quevedo et al 2006b). …”

Habitat partitioning in endangered Cantabrian capercaillie Tetrao urogallus cantabricus

“…Cantabrian capercaillie occupies a very southerly range within the grouse family (Quevedo et al 2006b), and has recently been identified as an Evolutionarily Significant Unit because of its unique ecological and genetic characteristics (Rodríguez-Muñoz et al 2007). The population appears to show low recruitment, with values as low as 0.54 juveniles per hen at the end of the summer and 74% of broodless hens in an 8-year period (Bañuelos et al this study, see ''Methods'' for details).…”

“…More precisely, the information available from observation of nests and of the size of juveniles in the summer surveys suggests that hatching takes place in June and early July. Forests in the northern watershed of the Cantabrian Range are highly fragmented (about 22% of the montane area above 700 m), dominated by beech and oak (Quevedo et al 2006b). Beech forests are more frequent in the central and eastern parts of the range, whereas oak dominates in the western areas.…”

“…However, most information about habitat use in capercaillie is biased towards cocks and often corresponds to their conspicuous behaviour at display areas and their surroundings in spring (e.g., Rolstad and Wegge 1987;Picozzi et al 1992). The Cantabrian capercaillie is no exception to this (Quevedo et al 2006b). A habitat suitability map, aimed as a conservation tool, was developed for this population from data corresponding to occupied and abandoned leks (Quevedo et al 2006a).…”