S. caninervis, the most common moss in the Mojave Desert, spends most of the year parched and brown, in a state of suspended animation waiting for the next rain. “It is something that only a mother can love,” said Dr. Mishler. But mosses are long-lived; a single group could easily be centennial.
Although S. caninervis made up more than two-thirds of the hypolytic moss at Wrightwood, the researchers identified another species, Tortula inermis. That moss generally grows at lower, warmer elevations, but was able to thrive at the Wrightwood site, appearing to rely on quartz for protection from the cold.
These quartzite oases, while common in Wrightwood, only arise in what Mrs. Ekwealor called a “Goldilocks” situation. If the quartz is too small, it will be easily blown away by the wind to allow something to grow underneath. If it is too large or opaque, not enough light will pass through for photosynthesis. If it’s too light, it could turn into a miniature greenhouse and capture even more heat. The quartz must be right: about an inch thick and milky enough to transmit up to 4 percent of the incident light.
But the vastness of the desert and the abundance of pebbles means that chance can become commonplace, Ekwealor said: “The probability is low, but many opportunities,” he said.
The study highlighted the importance of microenvironments that can be invisible to the human eye, added Ekwealor. Dr. Warren-Rhodes noted that hypolytic communities, however small, affect the carbon cycle and soil conservation.
After presenting this research at various conferences, Ms. Ekwealor said that she now receives sporadic texts from people who identify hypolytic mosses across the country. “I hope people start turning rocks to see what else is out there,” he said. After a pause, she added: “And gently repositioning them so the moss can survive.”
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