Spring Arrives Early Across the US

March 6, 2020

Dr. Theresa Crimmins recently contributed an article to The Conversation discussing how climate change has caused shifts in seasonal biological events, such as when plants leaf out and flower. USA NPN uses biological data collected by professional and volunteer scientists to develop predictive models and maps that are freely accessible to the public here. The results have received national attention and in the past few months, Dr. Crimmins has also discussed her work with KJZZ Radio and The Weather Channel. 
A recent analysis of this data found that Spring is arriving earlier in Arizona and throughout much of the country, shifting up to three weeks earlier in the past 70 years. This is concerning for ecologists because organisms respond differently to shifts in cues that initiate spring activity. In some cases, a pair of species that have traditionally relied on each other (such as a flower and its pollinator) experience reduced overlap in the timing of their spring emergence because the environmental cues (i.e. temperature, precipitation, day length) synchronizing the relationship between the two species no longer sync up. For example, an insect may no longer emerge at the same time that a plant is flowering because the plant, but not the insect, has delayed flowering in response to temperature. Such asynchronies could hinder survival and reproduction for plants and animals alike, ultimately changing how an ecosystem functions and which species are most common in the area.
The USA National Phenological Network (NPN) also hosts a citizen science database, Nature?s Notebook, for volunteer observers and professional researchers to submit their phenological data. Data from observers across the country is available publicly and compiled in an online database at NPN. The platform allows anyone to explore seasonal changes across the country for a specific species or taxa, offering an invaluable resource to researchers, farmers, teachers, and resource managers nationwide to better understand how seasons are progressing within and across years. 
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