By Andrew Knapp
Of all the varied landscapes of the North American continent, none boasts more extremes than California’s Death Valley. Named for its harsh environment and capacity for doing away with poorly-prepared travellers, it boasts the continent’s lowest point (at 86m below sea level), the world’s highest reliably recorded air temperature (56.7 °C, at the aptly-named Furnace Creek), and sees only 60 to 70mm of rain per year on average. Death Valley is the perfect place to look at biological adaptations to desert environments, and so in March 2016, during our field course in California, cohort 2 of the London NERC DTP paid a visit to this iconic place.
In order to survive here, plants and animals must avoid the harsher environmental extremes that the valley throws at them. Desert plants are well adapted to deal with critically low levels of water. Cacti are familiar as the classic desert plant, able to store water in their fleshy stems to see them through the toughest times, and in Death Valley, the hardy creosote bush (Larrea tridentata) dots the dunes and hillsides. Less obvious are the flowering plants which remain dormant as seeds in the soil. These plants only flourish briefly after rare rainfall, but can transform the barren moonscape of the valley into a carpet of colour.
Occasionally, global events can have dramatic effects on the conditions in the valley. The ongoing 2014-2016 El Niño event is one of the strongest on record. El Niño has the capacity to influence global weather patterns, and has caused severe rainstorms to sweep across California in early 2016. Such is the amount of water brought in by these storm fronts, the mountains that normally prevent rain from reaching Death Valley have proved little obstacle. The first months of 2016 have brought unusually heavy rainfall and plant life has exploded as a result, creating the valley’s first ‘super bloom’ since 2005. Fortunately for us, our visit coincided with this once in a decade event.
Driving south, the yellow haze that appeared over the valley floor revealed itself to be a blanket of the desert sunflower, Geraea canescens, stretching as far as the eye could see. Also dotted across the plain were a cornucopia of other desert flowers in white, blue and purple. Though their appearance is only brief, these flowers provide a boon for a wealth of pollinating insects and other desert animals. And, as quickly as they appear, these plants once again fade into the sand and stones of the desert. Those that have been pollinated will set seeds for the next generation of desert flowers, ready to burst into life at the next hint of rain. It turns out Death Valley ain’t so dead after all.