Joshua Trees in Transition

Joshua tree habitat. Tom’s Camp at the foot of Conglomerate Mesa, Inyo County. Photo: Greg Suba

Climate change is happening in real time in the Mojave where occurrences of the iconic Joshua tree (Yucca brevifolia) are growing smaller and changing. Many areas of the Mojave have grown too warm to grow new trees.

According to Cameron Barrows of UC Riverside, climate models using a 3-degree Celsius increase, show that the range of Yucca brevifolia could be reduced up to 90 percent by the end of this century.

Joshua trees are now “climbing” uphill with increasing occurrences along elevational gradients in the Mojave. These are transitional habitats either on higher microhabitat islands or along the edges of its range where cooler and wetter conditions allow plants to reproduce and survive.

 

Scientists from numerous academic institutions and the US Geological Society have initiated a collaboration to study the effect of climate change on the Joshua tree, particularly at the edge of its range. Since 2016, CNPS has collaborated with the Joshua Tree Genome Project (www.joshuatreegenome.org), drawing upon our citizen scientist members to collect data and plant tissues for molecular genetic analyses. At the CNPS Conservation Conference in February CNPS hosted a meeting of prospective volunteers and initiated planning efforts for a large scale contribution to this important project.

 

Wildlife, like this Scott’s Oriole, depends on Joshua Trees Photo: Rob Gowan

What you can do

Similar to our microphyll woodlands campaign, we ask that you share CNPS social media and outreach on behalf of Joshua trees. CNPS also will be meeting with BLM staff and partnering with the Joshua Tree Genome Project to conduct a training for CNPS members to collect data on Joshua trees in transitional habitats. Contact Nick Jensen, CNPS Southern California Conservation Analyst for more information about how to get involved with Joshua tree citizen science.


Nick Jensen, PhD, is the CNPS Southern California conservation analyst

 

One Comment

  1. I have a naturally occuring large Joshua tree on my property in the mountains above Palmdale CA. It seems to be the last one I can fine on the edge of the range where the San Gabriel Mtns begin their ascent in my area. If you would like samples I can happily provide. The location of the tree is
    (34.477641, -118.080513)

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