Spatially heterogeneous shifts in vegetation phenology induced by climate change threaten the integrity of the avian migration network

By Jie Wei, Fei Xu, Ella F. Cole, Ben C. Sheldon, Willem F. de Boer, Ben Wielstra, Haohuan Fu, Peng Gong & Yali Si

Climate change alters the timing of natural events differently in each region. This can lead to a growing mismatch between the availability of food and the supposed arrival of the birds in a certain area. Such heterogeneous shifts in food phenology induced by spatially heterogeneous climate change could pose a challenge to migratory birds by reducing their opportunity for food availability along the migration path and consequently influencing their survival and reproduction.

Migratory birds typically have a wintering area, a number of stopover areas where to rest and feed, and a breeding area. All of these regions are interconnected, forming a network. This study aims to investigate how well this migration network could still facilitate the birds’ migration (so-called the ‘migration network integrity’) under the impact of spatially heterogeneous climate change.

One of the migratory bird species that was included in the research
Cygnus columbianus by Fei Xu

Network integrity change of 16 migratory herbivorous waterfowl species

We developed a novel graph-based approach to quantify this problem and deploy it to evaluate the condition of the heterogeneous shifts in vegetation phenology for 16 migratory herbivorous waterfowl species in Asia. We compared the functioning of the networks over the past 21 years (a period with climate change), and compared this with an imaginary 21-year period without climate change (considering only the average seasonal fluctuations). We show that climate change-induced heterogeneous shifts in vegetation phenology could cause a 12% loss of migration network integrity on average across all study species. Species that winter at relatively lower latitudes are subjected to a higher loss of integrity in their migration network. These findings highlight the susceptibility of migratory species to climate change. Our proposed methodological framework could be applied to migratory species in general to yield an accurate assessment of the exposure under climate change and help to identify actions for biodiversity conservation in the face of climate-related risks.

The full article can be found here