San Diego is so arid, it can leave mushroom hunters foraging for irrigation. Try parks and cemeteries, some suggest. Or go see local species on display at the annual Fungus Fair in Balboa Park on Sunday (February 15).
No one knows how many kinds of mushrooms there are in San Diego, what medicinal or other properties they may have, where they grow, or how they’re doing in a changing climate. It’s not just chefs who want to know.
“It is clearly a scientific question that needs answering — and one I’ve been enjoying trying to help answer,” says Dr. Mary Ann Hawke, a UCSD plant ecologist at Scripps Institution of Oceanography. Hawke is working on a project to document the county’s mushrooms — part of an international effort to “barcode” species by sequencing their DNA.
San Diego has fewer kinds than elsewhere in North America due to the climate, she says. But even though the county yields fewer examples for the fungal library, Hawke says our unique habitats, especially arid lands, may support “some interesting or endemic species” that only grow in a limited range.
Mushrooms are the fruit of fungi, which belong to a kingdom of in-between organisms that share traits of both animals and plants and recycle nutrients through ecosystems. Fungi also provide antibiotics such as penicillin and other drugs.
The specimens found in San Diego will be entered in the International Barcode of Life database, which researchers say will revamp the field of conservation, providing a global reference library. Worldwide, only about 7 percent of fungi have been described.
San Diego may be a “biodiversity hotspot,” but the loss of habitat like vernal pools hasn’t been offset by listing any of its mushrooms as threatened or endangered, notes the website of the San Diego Floral Association
Hawke shares the task of cataloging species with members of the San Diego Citizen Science Network (which she helped found) and the San Diego Mycological Society, which hosts the Fungus Fair.
Local mushrooms are collected and preserved at the San Diego Natural History Museum. Currently, there are about 100 fungal specimens archived in the herbarium, she says. Far fewer have been prepared for barcoding.
“We've been trying in recent years to voucher some of the specimens brought in for our annual Fungus Fair,” Hawke says.
To contribute specimens to the herbarium isn’t all fun and foraging. Finding them is trickier than tracking down plants since mushrooms “are so ephemeral and dependent on weather,” Hawke says. And mushroom hunters don’t always want to share their secret locations.
After the samples have been identified, dried, and frozen to kill any pests, there’s data collection and entry, which includes the latitude and longitude where they were found.
“All that is currently being done on a volunteer basis,” Hawke says, mentioning another chore — fundraising to afford the specialized storage boxes, space, curation, and lab work.
To make the DNA barcoding effort cost-effective — because of specialized equipment and protocol — 96 samples must be collected and analyzed together. So far, they have samples from about 30 specimens that have been barcoded, Hawke says. Those bits of tissue now sit in the freezer “waiting until the rest are collected.”