California butterflies are reeling from a one-two punch of climate change and land development, says an unprecedented analysis led by UC Davis butterfly expert Arthur Shapiro. Their most significant findings:
•Butterfly diversity (the number of different species present) is falling fast at all the sites near sea level. It is declining more slowly or holding roughly constant in the mountains, except at tree line.
•At tree line, butterfly diversity is actually going up, as lower-elevation species react to the warming climate by moving upslope to higher, cooler elevations.
•Diversity among high-elevation butterflies is beginning to fall as temperatures become uncomfortably warm for them and, Shapiro says, “There is nowhere to go except heaven.”