Amateur naturalists help track shifting seasons as climate changes

By David Richardson
9 Apr 2012 Susan Peters, who moved from the East Coast to Tucson, Ariz., a couple of years ago, calls her adopted town an “oasis” — never mind that it only gets 12.6 inches of rain each year on average. “I have a very green, beautiful yard with desert-adapted plants, not the East Coast kind of thing,” she says. She especially likes her 35-year-old saguaro cactus — the kind “you always see in Westerns,” she says. But if her cactus is ever going to land a starring role in the movies, it’s going to need to grow some arms, and Peters says that could take another 40 years. It’s also going to require water — lots of it, and somehow it doesn’t look as if that’s in the cards. In recent decades, the Tucson area has suffered the grip of a combination of sustained drought and high temperatures possibly unrivaled since medieval times. As they say in the movies, “the West is changing,” and so is the East, and everything in between — and this includes those most dependable bellwethers, the seasons. Now Susan Peters is joining a posse of citizen scientists who are helping track these changes, and their many implications for plants and people alike. Spring is arriving ever earlier — an average of one day earlier each decade since the 1950s — and for areas surrounding cities, the advance of the seasons is even more dramatic. In February, researchers at the University of Maryland reported that in areas around East Coast cities, spring has been arriving five days earlier than in rural areas, and summers have been lingering ten days longer, due to the combined effects of climate change and the urban heat island effect. And it’s not just seasonal temperatures that are changing, it’s also rainfall patterns, moisture availability, and the timing of meteorological events such as snowmelt. An early spring may sound like something to celebrate, but scientists say sudden shifts in any of these may throw Mother Nature for a loop. Scientists from Stanford and the University of Maryland, for example, have found that unseasonably early snowmelt in the Colorado mountains causes whole stands of wildflowers to pop up too soon, only to be devastated by early spring frosts. The resulting shortage of flowers for forage can ricochet to affect pollinators like bees, butterflies, and hummingbirds that must either starve, or go elsewhere. Fewer pollinators means fewer plants, triggering a cascade that could lead to an avalanche of regional extinctions. […]