Mushroom Boom: Hobby records show climate-change boost

Mushrooms in England are both popping up earlier and staying around longer than they used to, according to 50 years of amateur naturalists’ records. Some species have changed their habits so drastically that they’re reproducing twice in the same year.

SNOW CONES. A late-spring snow covers sulfur tuft mushrooms in southern England, where they once fruited only in the fall. Image © Science

Because frosts rarely occur before Christmas, the fly agaric now fruits later in the year than it once did. Image © Science

Fifty years ago, mushroom hunters wishing to find the mosaic puffball would have gone looking in September. Today, these mushrooms are more likely to be found in July. Image © Science

“This is the first time anybody has bothered to look at how fungi are responding [to warming],” says Alan C. Gange of Royal Holloway, University of London. “The trends are dramatic.”

He says that the inspiration for the study came from his father, Edward Gange, who for decades had kept detailed records of local mushrooms. After retiring from stone masonry, the elder Gange bought a computer, learned how to use a spreadsheet program, and entered his sightings, along with those of other fungi enthusiasts in southern England. He ended up with 52,000 observations.

“I suddenly realized, here was an enormous resource,” says Alan Gange. A researcher in microbial ecology, he worked through the records with his father and two colleagues. Many climate-change studies focus on spring events such as advances in blooming or bird nesting. The mushroom analysis, however, focused on 315 species that normally fruit in the fall. The team checked the history of each species to see how its fruiting dates related to changes in regional temperature and rainfall.

In the 1950s, the average fruiting season for the mushrooms in the sample lasted 33 days. In this decade, the season has more than doubled, to almost 75 days. Eighty-five of the species have started fruiting earlier, advancing almost 9 days per decade, while 105 species have been hanging around about a week longer.

Several species have advanced dramatically. The common fairy-ring mushroom used to send up its rings of beige caps in lawns and fields in September. “Now, it’s July,” says Alan Gange. Sulfur tuft mushrooms, which once fruited only in the fall, often send up clumps of little caps early in the spring as well. Gange and his colleagues report their findings in the April 6 Science.

Compared with other creatures shown to be affected by climate change, “fungi are especially sensitive,” says Gange. Would he expect such changes elsewhere? “In North America—certainly,” he says.

“I was surprised at the study,” says mycologist David Hibbett of Clark University in Worcester, Mass. The work shows unusually big shifts in species’ habits, but “I buy it,” he says.

The species in the study perform valuable services in their ecosystems, Hibbett points out. Some break down leaf litter and other debris, and many of them envelop tree roots. The fungi siphon carbon from a plant but boost its supply of nutrients such as nitrogen and phosphorus.

Mycologist Rytas Vilgalys of Duke University in Durham, N.C., also welcomes the new work, though he cautions that, so far, “you can’t really predict what the effect will be” of the longer fungal seasons. He and his colleagues reported last year that, in a patch of forest, enhancing the planet-warming gas carbon dioxide changes the soil-fungus community, possibly influencing nutrient flow to the trees.

In addition to Gange’s findings, the final report in which the Intergovernmental Panel on Climate Change considers a wide range of ecological effects of warming trends is scheduled for release this week.

Susan Milius

Susan Milius is the life sciences writer, covering organismal biology and evolution, and has a special passion for plants, fungi and invertebrates. She studied biology and English literature.

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