Global niche shifts of rice and its weak adaptability to climate change

Abstract

Rice (Oryza sativa L.) is a staple crop cultivated on a global scale that plays an essential role in feeding the rapidly expanding human population. However, its ability to do so may be affected by climate change, especially if it exhibits strong niche and range stability. It is therefore important to clarify whether rice shows strong niche and range lability. Here, we used niche dynamics and species distribution models (SDMs) to investigate niche and range shifts between rice and its wild progenitor. Our results showed that niche expansion of rice in response to cultivation may have been much more rapid than niche expansion by natural selection in the wild progenitor, enabling rice to become a global staple crop. Rice cultivation, which causes rice to grow in climatic conditions different from those of its wild progenitor, has promoted niche shifts. These shifts have resulted in range shifts between rice and its wild progenitor; small niche shifts can result in large range shifts, and the former may therefore require much more attention. However, rice did not show high niche lability: it conserved the niche spaces inherited from its wild progenitor despite its long history of cultivation, although it exhibited greater niche breadth than its wild progenitor and has expanded its niche to hotter, colder, drier, and more fluctuating environments. This result suggests that rice may not show strong adaptability to future climate change. Significant attention should be paid to rice responses to future climate change scenarios and to the effects of changes in rice production on global food security.