Joshua tree faces extinction
17 Jul 2019
Climate change could be responsible for the near extinction of Joshua trees by the end of this century.
University of California, Riverside, scientists enlisted volunteers to help gather data about more than 4,000 of the trees in Joshua Tree National Park, California.
Using field measurements and statistical models, they found efforts to reduce heat-trapping gases in the atmosphere would save 19% of the Joshua tree habitat after the year 2070. But if no such efforts were made, no reduction in carbon emissions would see the park retain 0.02% of its Joshua tree habitat.
UCR plant ecologist Lynn Sweet said: “The fate of these unusual, amazing trees is in all of our hands. Their numbers will decline, but how much depends on us.”
The Yucca brevifolia species of tree, commonly known as the Joshua tree, is native to south-western parts of the US. The species has existed since the Pleistocene era, about 2.5 million years ago.
Individual Joshua trees can live up to 300 years by storing large reserves of water to survive droughts. But California’s 376-week drought that came to an end in March left some parts of the ground unable to support new saplings, which cannot hold reserves in this way.
Severe droughts are likely to become the norm as modern climate change continues to develop, the researchers say their paper, published in Ecosphere.
The species is also affected by smog from car and industrial exhaust, which deposits nitrogen on the ground and feeds non-native grasses that act as kindling. US Park Service is removing these invasive plants to prevent the resulting wildfires.
