The Joshua tree’s survival depends on well-timed rainfall
Chapter ONE JOSHUA TREE NATIONAL PARK in southern California the mountainous Mojave Desert meets and mingles with the low-lying Sonoran Desert in Joshua Tree National Park JTNP The park protects 1,238 square miles 3,207 sq km an area larger than the state of Rhode Island 1 Despite the harsh conditions the park supports a diverse array of plant life Hundreds of plants live in JTNP Many of those plants are wildflowers that paint the low-lying areas of the park in dazzling displays after spring rains drawing hundreds of thousands of tourists Humans are not the only visitors More than 250 bird species have been recorded in JTNP though only 78 of those stay in the park to breed 2 Others stop over during migration for rest and refreshment and some 5
wander in from nearby mountains to escape periods of heavy snow The park also provides homes for 52 species of mammals 44 species of reptiles and two species of amphibians 3 It also has a vast number of arthropods including 75 species of butterflies 4 RESTORING THE DESERT JTNP’s land was dotted with hundreds of mines which were created by prospectors in the 1800s Native plants struggled to grow throughout much of the area Some areas had been stripped by miners for fuel and for mining props while others had been cleared by homesteaders for unsuccessful attempts at dryland farming Hundreds of miles of roads snaked through the desert People could easily drive into sensitive areas where they might trample or steal unique desert plants Traffic also brought seeds from non-native plants In the 1970s managers started tackling challenges in JTNP beginning with the tamarisk tree an invasive species Originally from Eurasia tamarisk was 6 NORTH AMERICAN DESERTS Four major deserts cover vast territories in North America Though all are dry location and rainfall patterns have lent different characteristics to each The Sonoran Desert stretches from southern Arizona and California down into Mexico Its mild winters and sporadic summer downpours nurture a diverse mix of temperate and tropical plant species The colder and slightly wetter Mojave Desert covers an area from southern California north to Nevada Arizona and Utah The Chihuahuan Desert reaches farthest south from southern New Mexico and Texas and into Mexico although it frequently suffers freezes in winters because of its high elevation The cold Great Basin Desert is the highest and farthest north of the four With parts reaching south into Arizona and New Mexico it also stretches north to Oregon and Idaho
deliberately planted by gardeners and landscapers to make windbreaks and shade These trees roots drink from deep underground stealing water from native species and leaching salt into the soil JTNP staff trekked far and wide throughout the national park to destroy tamarisks that had found their way to many remote springs and oases Soon managers added new targets such as Asian mustard tumbleweed and invasive grasses These non-native grasses include fountain grass which outcompetes native bunch grasses and two grasses that feed large fires in areas that are not adapted to burn Over time people at JTNP have removed thousands of invasive plants freeing springs in the park from both tamarisks and fountain grass Getting rid of unwanted species is one part of restoration but another key step is returning native species Pieces of land in JTNP had never fully recovered from the destruction wrought by miners and homesteaders Early attempts to replant old gravel pits stalled as seeds struggled to germinate and 7 HISTORY OF JTNP In the 1920s Pasadena California resident Minerva Hoyt became concerned by the loss of desert vegetation to cactus poachers These poachers snatched cacti from the desert and sold them for cactus gardens in places like Los Angeles Hoyt started a conservation movement that led to the establishment of what was then the Joshua Tree National Monument in 1936 In 1976 the government designated approximately 80 percent of the monument as wilderness protected from further roads and mechanized vehicles 5 In 1994 a growing awareness of the desert as a unique and valuable ecosystem led to the California Desert Protection Act Along with increased protections for other deserts the act changed Joshua Tree from a national monument into a national park and expanded it to its current size Since 2009 85 percent of JTNP is classified as wilderness Viewed from the roadside the dry land only hints at hidden vitality but closer examination reveals a giant mosaic of an ecosystem intensely beautiful and complex 6 A description of JTNP from National Parks of the American West
