Summit County Citizens Voice

Earliest bloom dates have advanced by six days in past few decades

Warmer temperatures in early spring could threaten the survival of some plant species.

By Summit Voice

SUMMIT COUNTY — There little doubt that a changing climate has led to an earlier spring bloom for many plants around the world. This reset of nature’s clock has been well-documented, as scientists track the earliest blooms of many different species.

In a new study, University of Alberta scientists say an early spring can threaten the plants it’s meant to welcome. The research study shows that climate change over the past 70 years has made some native wildflowers and trees more vulnerable to damaging frosts, and ultimately, threatening reproduction.

U of A PhD candidate Elisabeth Beaubien and her supervisor, professor Andreas Hamann of the Department of Renewable Resources, studied the life cycle of central Alberta spring blooms, spanning 1936 to 2006, evaluating climate trends and the corresponding changes in bloom times for seven plant species.

Using thermal time models, the researchers found that the bloom dates for early spring species such as prairie crocuses and aspen trees had advanced by two weeks over the stretch of seven decades, with later-blooming species such as saskatoon and chokecherry bushes being pushed ahead by up to six days.

The average winter monthly temperature increased considerably over 70 years, with the greatest change noted in February, which warmed by 5.3 degrees Celsius.

The study, funded by grants from NSERC and Alberta Ingenuity, appears in the July issue of Bioscience.

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