Figure 8.15 First flowering dates for plants in Concord, Massachusetts. (a) The mean flowering time today is 7 days earlier than in the 1850s. Error bars are standard errors. (b) The variation in first flowering time is associated with the mean temperature of the 1 or 2 months preceding each species’ flowering time.

Data from A. J. Miller-Rushing and R. B. Primack, Global warming and flowering times in Thoreau’s Concord: A community perspective, Ecology 89 (2008): 332–341.