The impact of climate change on cherry trees and other species in Japan

Studies from throughout the world have provided evidence that climate change is already affecting the ecology and persistence of species. Japan contributes valuable insights into understanding these changes through long-term records of the timing of cherry blossoms and other phenomena of ecological and cultural interest. The wide latitudinal spread of Japan also provides an opportunity to examine species over a broad range of environmental conditions. In this review, we examine phenological studies that have taken place in Japan and summarize their significance to climate change and conservation research. In Kyoto, records of the timing of celebrations of cherry blossom festivals going back to the 9th century reconstruct the past climate and demonstrate the local increase in temperature associated with global warming and urbanization. This record is probably the longest annual record of phenology from anyplace in the world and shows that cherries are currently flowering earlier than they have at any time during the previous 1200 years. Detailed mapping of cherry tree flowering times in and around Osaka and other cities in Japan show that urbanization causes plants to flower earlier within the city environs than in nearby parks and outlying suburban areas. Flowering records from a large cherry arboretum at Mt. Takao, on the outskirts of Tokyo, show that both among and within species, early flowering is associated with greater responsiveness to temperature variation. Lastly, records of phenology for a wide range of plants and animals recorded at over 100 weather stations throughout Japan show that species vary greatly in their phenological responses to climate change, and highlight ecological relationships that need to be investigated in the field. Together, these studies provide important insights into how species are responding to climate change in Japan. Further research, particularly targeted field observations and experiments, is needed to build on these findings and to improve our understanding of how climate change is altering biological communities and how it will continue to affect them in the future.