Bird use of fruit orchards and vineyards in Japan: Mitigating a knowledge gap with a systematic review of published and grey literature

Abstract

Perennial farmlands such as fruit orchards and vineyards often substitute for natural habitats and provide nesting and foraging habitats for birds. Bird use of perennial farmlands has been investigated mainly in Europe and North America, but far less in Asia, which hosts one-third of identified biodiversity hotspots. We aimed to fill this knowledge gap by performing a systematic review of bird studies in fruit orchards and vineyards in Japan. We screened literature written in English or Japanese including both published and non-peer-reviewed (grey material, e.g., books, abstracts of annual meetings, blogs, and unpublished surveys). The review identified 31 bird species, including four Red List species, that nest in orchards and vineyards in Japan. Several studies have provided insights into the habitat quality of fruit orchards, which appears to vary among bird species. Other studies have reported: (1) the effects of orchard management on bird diversity (e.g., positive effects of organic farming and grass cover on bird richness and abundance); and (2) the ecosystem services by birds (e.g., reduction of pest rodents by predatory Ural Owls Strix uralensis). Our review demonstrates the potential importance of fruit orchards and vineyards to bird species that have adapted to human-modified landscapes, although more quantitative studies are needed to investigate the actual breeding performance of birds. We also illustrate the importance of non-English-language literature, including grey literature, to mitigate ecological knowledge gaps in countries where English is not the first language.