Abstract: There are two main life cycles in plants, annual and perennial. These life cycles are associated with different traits, which determine ecosystem services and functioning. Although life cycles are textbook examples of plant adaptation to different environments, we lack comprehensive knowledge regarding global distributional patterns. Here, we assembled an extensive database of plant life cycle assignments of 235,000 plant species coupled with millions of georeferenced data points to map the worldwide biogeography of life cycles. We found that annuals are half as common as initially thought, accounting for only 6% of plant species. Our analyses indicate that annuals are favored in hot and dry regions, and this pattern remains consistent among different families, indicating convergent evolution. However, a more accurate model shows that annual species’ prevalence is driven by temperature and precipitation in the driest quarter (rather than annual means), explaining, for example, why some Mediterranean systems have more annuals than deserts. Lastly, we demonstrate that increasing climate variability and anthropogenic disturbance likewise increase the favorability of annuals. Overall, our analysis raises concerns for the future of ecosystem services provided by perennials because the ongoing climate and land-use changes are leading to an annuals-dominated world.
