Abstract
In shaping how ecosystems respond to climatic change, ecosystem structure can dominate over physiological responses of individuals, especially under conditions of multiple, simultaneous changes in environmental factors. Ecological succession drives large-scale changes in ecosystem structure over time, but the mechanisms whereby climatic change alters succession remain unresolved. Here, we investigate effects of atmospheric and climatic change on seedling establishment, recognizing that small shifts in seedling establishment of different species may have long-term repercussions on the transition of fields to forests in the future. Our 4-year experiment in an old-field ecosystem revealed that response of seedling emergence to different combinations of atmospheric CO2 concentration, air temperature, and soil moisture depends on seed phenology, the timing of seed arrival into an ecosystem. We conclude that seed phenology is an important plant trait that can shape, and help predict, the trajectories of ecosystems under climatic change.
