关键词: 城市绿地, 迁徙陆鸟, 中停地, 能量补给, 留野

Abstract

Aims: Migratory birds are experiencing widespread population declines, highlighting the urgency of effective conservation actions. Various migratory bird species, especially migratory landbirds, have been documented to use urban green space as stopover sites, including for refueling purposes. Considering the ongoing global urbanization, urban green space can potentially present great opportunities for the conservation of migratory landbirds by providing high-quality stopover habitats for these birds. However, this prospect premises on the accurate assessment of the stopover habitat quality of urban green space for migratory landbirds, including under specific management measures. In this study, we assessed the stopover habitat quality of an urban park in Beijing for migratory landbirds over a nine-year period, and we tested the response of this quality to a set of urban wilding measures implemented by the park to increase the naturalness of park vegetation.

Methods: We measured the stopover habitat quality for migratory landbirds by refueling conditions as represented by the rate of birds’ body mass gain, focusing on the Cuihu Wetland Park in the northwestern corner of central Beijing where a bird ringing program has been running since 2014. We used ringing data from 2015 to 2023 to estimate the hourly rate of body mass gain for each species within each migration season, for the species-season combinations with ≥ 50 captured individuals. We further examined whether this rate responded positively to the urban wilding measures implemented in the park since 2017 (i.e. allowing the vegetation to naturally develop by not mowing, pruning, or clearing leaflitter and seedlings).

Results: Of the 19 species-season combinations we were able to assess, we observed significant hourly body mass gain for the majority of combinations, involving 12 migratory landbird species from four families. However, overall, we did not find obvious impacts of urban wilding measures on birds’ refueling conditions, with only two species-season combinations showing indications of hourly body mass gain under these measures.

Conclusions: Our results suggest that Cuihu Wetland Park can offer positive refueling conditions for multiple species of migratory landbirds that have diverse dietary preferences and foraging strategies, providing scientific evidence for the value of urban green space as stopover habitat for migratory landbirds. Additionally, urban wilding measures may have enhanced these refueling conditions for at least some of the species, although further research is needed to robustly test this potential benefit. More generally, our study also serves as a proof-of-concept case for wider assessments of stopover habitat quality for migratory landbirds using data on their refueling performance.

Key words: urban green space, migratory landbirds, stopover site, refueling, biodiversity-friendly measures