For everything there was a season: phenological shifts in the Tetons

Around the world, phenology — the timing of ecological events — is shifting as the climate warms. This can lead to a variety of consequences for individual species and entire ecological communities. Grand Teton National Park biologists have identified this topic (“effect of earlier plant flowering on pollinators and wildlife”) as one of their priority research needs. We assembled phenological observations of first flowering dates for 49 species collected by Frank Craighead, Jr. in the 1970s, before significant warming occurred. In 2016 we began standardized phenological observations of these same species, plus an additional 61 for a total of 110 species, in the same locations. First flowering date for 65% of the species with historic records correlated significantly with mean spring temperature; these species are therefore expected to flower earlier now than in the 1970s. Early spring flowers had the largest shifts in phenology, emerging an average of 21 days earlier now relative to the 1970s. Yet not all species are emerging earlier. In particular, phenology of late summer/early fall flowering plants was largely unchanged. In 2017, we initiated pollinator collections at our key phenology sites. Additional years of observations will allow us to better understand plant-pollinator interactions and identify potential phenological mismatches.   Featured photo by Shawna Wolf, taken from the AMK Ranch photo collection.