Have you ever been to Joshua Tree in the Mojave Desert? The pollination system there is extraordinary to me. Yucca moths pollinate Joshua trees. Then, they lay their eggs inside the tree flowers. This creates an interdependent relationship for survival. However, the future of this remarkable pollination system is threatened, however, by ongoing global climate change.
According to computer models, Joshua trees may disappear from much of their current range within the next 100 years.
As one response, in March 2014, Todd Esque, from the U.S. Geological Survey, and evolutionary biologist Chris Smith, from Willamette University in Salem, Ore., offered a four-day course called “The Race North: Population Ecology of Joshua Trees In an Era of Climate Change.”
Observations in the region on the effects on Joshua trees have been telling. Interestingly enough, currently, Joshua trees seem to be “experiencing something of a population boom” according to Smith, at the northern limit of their current range, possibly in response to increasingly warmer, drier conditions to the south. However, he’s also observed with other scientists that there is evidence that the trees are fading from parts of the southern end of the national park range. In April 2013, Joshua trees burst into beautiful flower across the Mojave desert and speculation and debate led some scientists and observers to think that the underlying cause of the spectacle was two prior years of drought triggered by a warming climate while others like Esque didn’t see the drought as the only factor behind the bloom. Still, he is extremely interested in monitoring how much of a challenge climate change will pose for Joshua trees and people.
Esque believes that every time climate events occur, some things survive and new species emerge. He sees that Joshua trees might be able thrive if they can respond quickly enough and spread their seeds far enough.
For the past 10 years, Esque has tried to produce the first comprehensive understanding of the tree’s life history. He has published studies on the future distribution of the Joshua tree as projected by combining a geostatistical analysis of 20th-century climates over the current range, future modeled climates, and paleoecological data showing responses to a past similar climate change. He also conducts workshops on the topics of Joshua Tree Community & Fire Impacts, use and development of State and Transition models in Western deserts and the survival of the Joshua tree.
Assessing the future range of Joshua trees is important enough to Todd Esque and the trees are beloved by many throughout the world.
Imagine reading this on a National Park Service brochure “Climate Change in National Parks.”
“Another dilemma for managers is occurring at Joshua Tree National Park. Joshua trees require cool winters and freezing temperatures in order to flower and set their seeds. Researchers have documented substantial mortality of Joshua trees and predict that because of climate warming, the trees will be unable to persist much longer within the park. Soon, Joshua trees may no longer be found in the park bearing their name.”
Unfortunately, you don’t have to imagine it, it’s already on the brochure. Scientists predict this could happen by 2100.
People all over the world come to enjoy the Joshua trees and I am impressed with Todd Esque’s work in trying to determine what we can do about this dilemma. Citizens can bolster his efforts by participating in citizen scientist classes offered on an ongoing basis at the Desert Institute.
I hope you appreciate this time-lapse that captures the ecosystems endangered by climate change that was created by filmmaker and photographer Sungjin Ahn when he discovered that Joshua Tree National Park might someday lose the right to that name. I certainly do.
Sources: Earth Island Institute, Joshua Tree National Park, Washington Times, USGS, Las Vegas Review-Journal, The Epoch Times, New Scientist, LA Times, Desert Institute at Joshua Tree National Park, National Park Service US Dept. of Interior, The Desert Sun, Vimeo