Early snowmelt and warmer, drier summers shrink postflowering transition times in subalpine wildflowers

Plant reproductive phenology-the timing of reproduction-is shifting rapidly with global climate change. Many studies focus on flowering responses to climate, but few investigate how postflowering processes, such as how quickly plants develop from flowering to seed dispersal, respond to environmental factors. We examined the climatic drivers of postflowering phenology in 28 species of western North American subalpine meadow plants over large spatial and temporal climate gradients. We took a Bayesian hierarchical approach to address whether and how climate influences the time it takes for wildflower populations to transition from flower to seed. Our previous work on the same species demonstrated that the initiation of flowering depends on snowmelt timing, with warmer temperatures and soil moisture also playing a role. Here, we found that for the majority of the flowering community, the same climate drivers also affected the time it takes to move from flowering to seed dispersal. Climate-sensitive species shortened flower-seed transitions when snow melted earlier, temperatures were warmer, and/or soil dried down more quickly-conditions we expect with higher frequency under climate change. Our work underscores the fact that predicting the impact of climate change on plant reproductive phenology demands empirical data on phases beyond flowering. Additionally, it suggests that some species face a future in which multiple environmental factors will push them towards more rapid transitions from flowering to postflowering phases, with potential effects on plants themselves and the many animal associates that rely on them, including frugivores and seed predators.