California series 3. Deserts

Cholla cactus garden in Joshua Tree NP. Image by K Simonaityte

Cholla cactus garden in Joshua Tree NP. Image by K Simonaityte

It took me forever to get around to write this third part, but I guess now is the most appropriate time to do it. Why’s that? Well, exactly one year ago I visited my first desert — in Joshua Tree National Park in the south east of California.

Visiting Joshua Tree was the most surreal experience. Imagine this: from our home in Davis, Ca. it took about 9 hours to get to the national park. Driving overnight. We entered Mojave desert as the sun was coming up and we still had good 3 hours to go. Sunrise in a desert is the most beautiful thing, especially when you’re all tired from not being able to fall asleep. We entered the park at around 9 in the morning and were on our feet until 9 in the evening. That day in the desert was such a haze; the brown-grey landscapes were so unusual, mountains in the distance and plains all around with the funny rock structures dotted all over and the desert plants toughing it all out. I was on a high from lack of sleep, the brightest blue skies I’ve ever seen, the high sun, restless wind, excitement of finally being there, and adrenaline from climbing and jumping and running on the weird rocks. If I had to describe being in the desert in one word, it would be “brightness”, I can still see and feel it when I close my eyes. For the northerner me the desert sun was overwhelming. (This really applies to California sun in general, but in other locations there usually are buildings or trees to give you shade and obscure your view of the skies. It is not so in the desert.)

Me and some rock at Joshua Tree NP. Image by Abhijeet Kulkarni.

Me and some rock at Joshua Tree NP. Image by Abhijeet Kulkarni.

The night, on the other hand, was a complete opposite. It was still very windy but other than that extremely quiet and so incredibly dark. The darkest night I’ve ever seen. (I know, I’ve been saying this a lot, but it truly was like that!) Prank: It was so dark that our fellow travelers scared the pants off of us on our way back from the restrooms — we didn’t see them lurking just a couple of metres away. Oh, and you can imagine the view of the stars!

***

Joshua trees. Image by K Simonaityte.

Joshua trees. Image by K Simonaityte.

Two deserts meet in Joshua Tree, the (relatively) wetter Mojave and the drier Sonoran. Creosote bush (Larrea tridentatadominate the landscape in the latter, with patches of ocotillo (Fouquieria splendensand the Jumping cholla cactus (Cylindropuntia fulgidahere and there. Joshua tree (Yucca brevifolia), after which the park is named, is the signature plant of the Mojave. Its appearance is bizarre to say the least, while its ecology is a textbook example of a facultative mutualism and co-evolution, involving yucca moth as the other benefiting partner. Yucca moth pollinates the flowers and lays its eggs inside them. Flowers then provide protection for the hatched larvae, while produced seeds serves as the food source. To avoid the larvae eating all of the seeds, the tree is known to abort the flowers which have too many eggs laid in them! Both the moth and the tree are dependent on each other for its survival, and the benefits received from this mutual exploitation are greater than the costs (i.e. loss of seeds, energy spent pollinating).

Joshua tree flowers. Image by K Simonaityte

Joshua tree flowers. Image by K Simonaityte

Deserts take up about 30 per cent of California. In addition to low elevation (mean ~300 m) hot Sonoran desert and mid-elevation (~1,000 m) warm Mojave, there is also high-elevation (~1,200-2,500 m) cold Great Basin desert in the north east of California. All three types share some common characteristics, including low precipitation, temperature extremes, windiness, high-light intensity, low-nutrient and alkaline soils, and low productivity. Despite these harsh conditions, California’s deserts are incredibly biodiverse: for example, compare 85 – 120 taxa found per hectare in the seemingly lifeless eastern Mojave desert bajada to 90 – 125 in the lush coastal redwood forests of Del Norte County. Vegetation displays specific adaptations to the desert conditions. These include succulence and CAM photosynthetic pathway; spines; hairy, waxy, small and drought-deciduous leaves; deep tap roots; photosynthetic stems; dwarfism and others.

Great Basin is dominated by four sagebrush Artemisia species; other shrubs include Greasewood Sarcobatus vermiculatus, Bitterbrush Purshia tridentata, Rabbitbrush Chrysothamnus spp., and Horsebrush Tetradymia spp. As for Mojave, in addition to creosote bush, Joshua tree, ocotillo and cholla cactus mentioned above, various Opuntia spp. (e.g. Beavertail cactus O. basilaris), Ambrosia spp. and others are found. It does rain in Mojave but only in winter; following these rains various desert annuals emerge and the burst of flowers of the multitude of colours transforms the desert — at least for a little while. Saguaro cactus Carnegia gigantea is the dominant species in the Sonoran desert, while mesquite and palo verde are also common.

Mojave desert flowers. Image by Dean Hueber.

Joshua Tree NP is the 15th largest national park in the US, covering area of nearly 3,200 sq km (in comparison, Cairngorms NP in Scottish Highlands covers about 4,500 sq km). Over half of the park’s territory is a designated Wilderness Area — area open for recreation but not exploitative development of any kind. However, while desert within Joshua Tree is protected, large tracts of California’s desert are affected by habitat conversion for solar power development, invasive species such as saltcedar Tamarix spp., and of course climate change. It is clear that larger areas need to be protected to ensure adequate conservation and management of the California’s unique desert ecosystems.

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Sunrise in Joshua Tree NP. Ocotillo bushes in the foreground. Image by K Simonaityte

Sunrise in Joshua Tree NP. Ocotillo bushes in the foreground. Image by K Simonaityte

Last thoughts: I was very lucky to get and see one more sunrise in the desert the next morning of our visit. We took a car and were just going what seemed for miles catching glimpses of the rising sun and absorbing the waking desert all around us. Visiting Joshua Tree was amazing, and even getting terribly ill just a day after we got back didn’t change that – it was totally worth it! Also, it was U2’s ‘Joshua Tree’ that made me want to visit the national park so bad, and so every time I now listen to the album all I can think of is the bright sun and blue skies and the twisted, spiky arms of the praying Joshua trees.

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4 responses to “California series 3. Deserts

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