The latest casualty in California's ongoing and massive drought comes from a rather arid place to begin with: The iconic Joshua tree, which grows only in the Mojave desert, is in trouble, reports the Los Angeles Times. "For Joshua trees, hotter, drier conditions are a problem—but a bigger problem is that what little rainfall occurs evaporates faster," says UC Riverside ecologist Cameron Barrows, who's digging into the trees' response to climate change and drought. "So, seedlings shrivel up and die before they can put down strong roots." With federal funding, Barrows is also trying to assess the effects of climate change on the plants and the animals they shelter, including yucca moths, skipper butterflies, termites, ants, desert night lizards, kangaroo rats, and 20 species of birds. "Beyond its importance as a critical refuge for desert species, the Joshua tree is a cultural signature of California's desert landscape," UC Berkeley biology post-doctoral fellow Rebecca Hernandez says.
Scientists predict that the trees will lose 90% of their current range in the 800,000-acre Joshua Tree National Park by the end of the century if the warmer, drier conditions continue. The park has seen 1.71 inches of rain this year. Precipitation averages about 4 inches per year. The species has weathered threats before: housing tracts and shopping centers in the 1980s and moist El Nino conditions in the 1990s. But can Joshua trees survive climate change? Computer models by Barrows and his team show the species retaining just 2% to 10% of its current range if global temperatures rise by 5 degrees Fahrenheit. "Since they grow for about 200 years, we won't see massive die-offs in our lifetime," says the park superintendent. "But we will see less recruitment of new trees."