Abstract:

Aims: This study aims to predict changes in plant distribution ranges under future climate change scenarios, providing critical insights for assessing species survival potential and biodiversity risks. The East Asian-North American disjunct genera, characterized by their intercontinental phylogenetic relationships and niche conservatism, serve as an ideal model system for investigating differential biotic responses to climate change across regions. This research systematically compares the responses of these plants to climate change between East Asia and North America, and explores the role of life forms (including trees, shrubs, lianas, and herbs) in this process. The goal is to deepen the understanding of biological response mechanisms to climate change and offer scientific support for developing targeted conservation strategies. 

Methods: Fifteen East Asian-North American disjunct genera with comparable intercontinental distributional ranges, comprising 71 species in total, were selected. The MaxEnt model was utilized to simulate their potential distributions under both current and future climate scenarios. Based on the modeling results, responses to future climate change were compared between regions (East Asia vs. North America) and among different life forms, focusing on three aspects: changes in suitable habitat area, latitudinal shift trends, and the degree of habitat fragmentation. 

Results: (1) North American species exhibited greater sensitivity to climate change than East Asian species, evidenced by a higher proportion of species experiencing significant changes in distribution area, more prevalent northward migration trends, and more pronounced habitat fragmentation. (2) The response of life forms to climate change showed regional differences: trees and lianas demonstrated stronger responses and more drastic distributional changes in North America; shrubs showed similar migration trends in both regions; herbs in East Asia displayed stronger fragmentation, whereas in North America they showed trends of expansion and enhanced connectivity. 

Conclusion: This study reveals regional differences and life-form dependencies in the responses of East Asian-North American disjunct taxa to climate change. It indicates that macro-topographic patterns and life-form characteristics jointly drive these disparities, highlighting the key role of topography in determining species' climatic resilience. The findings provide important scientific support for identifying cross-regional conservation priorities and formulating life-form-specific adaptation strategies.

Key words: East Asian-North American disjunct distribution, life form, climate change, MaxEnt model, range shift, biodiversity