A trait-based approach to seasonal dynamics of an alpine and subalpine passerine bird assemblage

• Published in: Journal of ornithology Vol. 163; no. 3; pp. 709 - 721
• Main Authors: Iijima, Daichi, Kobayashi, Atsushi, Morimoto, Gen, Hasegawa, Masami, Abe, Seiya, Murakami, Masashi
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.07.2022; Springer Nature B.V
• Subjects: Adaptation; Biomedical and Life Sciences; Birds; Body mass; Body temperature; Breeding seasons; Climate change; Community structure; Ecology; Fish & Wildlife Biology & Management; Food availability; Foraging behavior; Life Sciences; Migratory species; Original Article; Overwintering behavior; Seasonal variations; Species composition; Temperature; Winter; Zoology; Community structure; Sequential arrival; Snowmelt; Extreme environment; Mountain ecosystem
• ISSN: 2193-7192; 2193-7206
• DOI: 10.1007/s10336-022-01962-9

The bird assemblages in high mountain ecosystems exhibit dramatic seasonal changes in community structure following the sequential arrival of species during the pre-breeding season. The investigation of this process should offer the great interest because of the vulnerability of alpine bird assemblages under climate change. In the present study, the mechanisms underlying the seasonal dynamics of a passerine bird assemblage in alpine and subalpine zones were investigated on Mount Norikura in central Japan. We empirically determined the arrival dates of 18 bird species and collected data on 6 traits: the number of food types and foraging methods, body mass, the lowest temperature in the northernmost wintering area, and the foraging and nesting strata. We analyzed the effects of these traits on the arrival date and found that the species with a lower temperature in the northernmost wintering area arrived earlier. We also found that species with smaller food types arrived earlier when the long-distance migratory species were excluded from the analysis. In addition, the annual dynamics of the assemblage and environments were examined. We found that temperature and snowpack were significantly associated according to the species composition changes. The functional properties of the assemblage became simpler in winter. Our findings suggest that bird assemblage dynamics from winter to summer are driven by the sequential arrival of species according to their abilities—behavioral and/or thermophysiological adaptations to cold temperatures in an environment characterized by lacking readily available food. Furthermore, cold temperatures and deep snowpack should restrict species inhabitance in winter.