A study finds that a trend toward earlier snowmelt driven by climate change may reduce the number of seeds subalpine plants produce and affect the plants' long-term persistence. Temperature shifts leading to early snowmelt often lead to events such as early blooming. However, the effect of early snowmelt on plant survival and reproduction is poorly understood. Diane R. Campbell analyzed 25 years of demographic data documenting the growth, survival, and seed production of two subalpine plants, Ipomopsis aggregata and Ipomopsis tenuituba, in the Colorado Rocky Mountains. The author compiled counts of flower number, fruit set, seeds per fruit, and seed predation, as well as measures of size and survival. Plants produced more seeds in years with late snowmelt than in years with early snowmelt, despite no apparent effect of snowmelt timing on flower number. Changing seed production and seedling establishment due to early snowmelt, in conjunction with decreased water availability, place the populations of I. tenuituba below replacement rates, and I. aggregata below replacement rates within the next four decades. According to the author, climate change endangers these plant populations even in the absence of overt signs such as bloom timing, illustrating the need to explore climate impacts on survival and reproduction.
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Article #18-20096: "Early snowmelt projected to cause population decline in a subalpine plant," by Diane R. Campbell.
MEDIA CONTACT: Diane R. Campbell, University of California, Irvine, CA; tel: 949-824-2242; e-mail: < drcampbe@uci.edu >
Proceedings of the National Academy of Sciences