In addition to the well-known limiting effect of cavity abundance on the density of hole-nesting passerines, other aspects of cavity availability may shape their communities as well. Notably, where there is a considerable aggregation of cavities, territory-holders may prevent the occupation of the nearest cavities by other birds, whereas a supply of diverse cavities may reduce interspecific competition. We used multivariate general linear models to explore whether, and how, variables describing the supply of small cavities are related to the density and diversity of hole-nesting passerine communities in 33 hemiboreal old forest stands. The total density of 12 species (1.3 ± 0.8 pairs/ha) increased with cavity density and diversity, but was not affected by cavity aggregation. As expected, cavity diversity also promoted bird diversity; indeed, the densities of different species were positively related to the densities of different cavity types. The results indicate that segregation in nest-cavity selection affects the co-occurrence of passerine species and, at the mean densities of small tree-cavities in the region (2.3/ha), cavity aggregation does not markedly reduce their availability. In conservation management, therefore, it is important to maintain a diverse supply of cavities in addition to their abundance, in order to sustain hole-nester communities.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.