Science Source

Climate change is advancing spring onset across the U.S. national park system

States that many US national parks are already at the extreme warm end of their historical temperature distributions. Seasonal changes in vegetation, such as pollen, seed, and fruit production, are important drivers of ecological processes in parks
States that phenology (the study of seasonal plant and animal life cycles) has been identified as a key indicator for park monitoring and is also one of the clearest biological responses to climate change
Evaluates the recent timing of spring onset (past 10–30 yr) in each US natural resource park relative to its historical range of variability across the past 112 yr[s] (1901–2012)
Finds that spring is advancing in approximately three-quarters of parks (76%), and 53% of parks are experiencing “extreme” early springs that exceed 95% of historical conditions
Finds, consistent with previous studies, that two US regions—the Southeast US, and the Northern US Rocky Mountains—do not display "early spring" markers
Projections suggest that all regions containing [national] parks will experience advances in the timing of spring onset by mid-century
Results demonstrate how changes in climate seasonality are important for understanding ecological responses to climate change
Discusses how results inform climate change adaptation challenges and opportunities facing [national] parks, with implications for other protected areas