Potential resource competition between an invasive mammal and native birds: overlap in tree cavity preferences of feral raccoons and Ural owls

• Kobayashi, Fumiya

• Toyama, Masahiro

• Koizumi, Itsuro

抄録

Invasive mammals include good tree climbers that use tree cavities for resting and nesting. Tree cavities are important but limited resources in most forests; thus, some invasive mammals can be serious competitors for native cavity-using species, especially cavity-nesting birds. Despite the potential impact, such inter-class competition has rarely been considered. We examined the possibility of resource competition for tree cavities between the invasive raccoon Procyon lotor and the native Ural owl Strix uralensis. Both species are nocturnal and use tree cavities during daytime. We assessed an overlap in cavity use for both species as an indication of potential competition by monitoring 341 cavities during their breeding season in a natural park in Hokkaido, Japan. Of 341 potentially available cavities, raccoons and Ural owls used 37 and 32, respectively. The characteristics of 58 cavities used by raccoons or owls were compared to 49 random cavities to determine if they selected cavities with certain characteristics. As predicted from a large amount of tree cavities and a low raccoon density in this managed forest, we did not find direct evidence of competition, such as physical interaction, intrusion to cavities, or habitat segregation. Cavity types used by both species overlapped considerably in terms of height, entrance size, depth, and other characteristics: their habitats were widely overlapped. Further, in four cavities, one species was replaced by the other. Given the similar habitat requirements, the invasive raccoon could be a potential competitor for Ural owl when raccoon density increases and/or cavity availability decreases, which is the case for many forests in Japan. This study suggests that potential threats of resource competition among not only closely but also distantly related taxa should be taken into consideration when studying the impacts of invasive species.

収録刊行物

• Biological Invasions

  Biological Invasions 16 (7), 1453-1464, 2014-07

  Springer

キーワード

• Alien species
• Habitat selection
• Inter-class competition
• Tree hollow

詳細情報

• CRID: 1050564288970281344
• NII論文ID: 120005510941
• NII書誌ID: AA11384974
• HANDLE: 2115/57419
• ISSN: 13873547
• 本文言語コード: en
• 資料種別: journal article
• データソース種別:
  • IRDB
  • CiNii Articles