Dr. Richard Primack and I recently authored an article entitled "Spring Budburst in a Changing Climate" in the journal American Scientist.
In the article, we describe the wide range of work the Primack Lab has done to investigate how climate change impacts the timing of leaf-out and other spring events in the temperate forests of historic Concord, MA and beyond. We summarize the key results found by past and present members of the Primack Lab through combining historic data sets, like the field notes of Henry David Thoreau, with current observations of spring phenology, as well as novel experiments.
One of the key findings we describe is that in Concord, climate change has resulted in varied shifts in timing between leaf-out, flowering, bird arrivals, and insect emergence. Since Thoreau recorded his observations in the 1850's, we estimate the following shifts have occurred in the timing of spring events as a result of climate change:
These estimates of long-term changes in spring timing demonstrate how the effects of climate change could be problematic for birds that are not responding to warming temperatures as quickly as their insect prey. In fact, the strong effect of warming on leaf-out and flowering in Concord, MA, combined with the limited ability of migratory birds to track temperature changes on their MA breeding grounds, has altered the overall order of events from Thoreau's time to present:
In addition to these taxon-level shifts, we delve into how species vary in their leaf-out times and responses to climate change, the benefits of leafing out early (i.e. a longer growing season in which to photosynthesize) and the dangers of leafing out early (i.e. an increased risk of vulnerable young leaves encountering frost). We also identify some important next steps in the study of climate change and phenology, including a greater focus on autumn events like leaf senescence and fruit ripening.
To read the American Scientist article, click HERE or e-mail me at firstname.lastname@example.org for a PDF.