Flowering schedules in alpine flowers are changing

A 39-year record of wildflower blooming in the Rocky Mountains  shows that climate change has altered the timing of blooming for most species in an alpine meadow.  (Link is to University of Maryland press release. Original paper published in PNAS).

Virginia bluebell, Mertensia virginica, Daniel Boone National Forest

The blooming season now runs from late April to late September instead of late May to early September. The response to climate change is complicated: some plants flower earlier, others for a longer time.

The complex changes in flowering times are producing what ecologists call “no-analog” communities that are not closely related to existing communities.  In the case of the meadow flowers, hummingbirds can no longer rely on a huge spring peak in blooming when rearing their young. Instead, the same number of blossoms are spread out over a longer period of time.  This reduces the amount of nectar available each day.

Phenology is the study of the scheduling of events in an organisms life. Long-term plant phenology studies are pretty rare. David Inouye, a distinguished conservation biologist at the University of Maryland, started this project in 1974 because of his interest in nectar sources for hummingbirds and bumble bees. He has continued this project every year since, along with his students and post-docs.

This study is important for several reasons:

  • It shows the value of very long-term studies.  Long-term research is hard to sustain and even harder to fund.  Yet without long-term studies like this, we would detect only the most severe and catastrophic effects of climate change.
  • It shows that the impacts of climate change are complex, with each species responding differently, and with relationships among species changing radically.
  • It demonstrates the importance of studying mountain habitats, where the effects of climate change on the lives of plants and animals can already be seen.