Thursday, May 30, 2013

Hunting for Botanical Biodiversity, Joshua Tree National Park


Lost Palms Oasis, Joshua Tree National Park
Imagine if we could gather together an enthusiastic multitude of biologists and interested citizens to comb through a location on a single weekend, seeking to identify every living thing that occurs in that one spot. Think of how much we could learn about ecological complexity, and of how the dimension of our knowledge of that place would unfold like a Chinese fan. It is like we are taking a biological snapshot, capturing a record of everything that is there at that point in time. Holding such a gathering is the aim of a “Bioblitz”, or Biodiversity Hunt: to positively identify as many species as possible over a day or two in a delineated area.
Staff at Joshua Tree National Park organized a series of four Biodiversity Hunts over the past three years, assembling more than 100 people to search, identify, and report on the biological richness of the park’s desert wetlands, the focus of this project. Rancho Santa Ana Botanic Garden (RSABG) botanists have been present at all four of these hunts, applying their botanical expertise to assist the National Park to identify plant species that reside within their boundaries, and more generally benefiting knowledge of Southern California’s botanical richness.

In March and April a group of botanists from the Garden, including Naomi Fraga, Sarah Degroot, Evan Meyer, Abby Hird, Loraine Washburn and Jessica Chu participated in the last two of these four Biodiversity Hunts. We spent four full days in Joshua Tree, doing thorough surveys for plants that occur around Cottonwood Springs and the Lost Palms Oasis, near the south entrance, and in Smithwater Canyon in the northwest of the Park. We joined birders, herpetologists, entomologists, and arachnologists, as well as students, photographers, and interested community members in a wide-ranging survey of these remarkable desert wetlands.

In March at Cottonwood Springs and Lost Palms Oasis, RSABG botanists fanned out into the washes and slopes, identifying common and dominant species as well as hunting for microsites where less common elements might be found, such as against a north-facing cliff face, in a more humid seep, or where the soil became richer in clay. We appreciated the shade of palms and cottonwoods as we hunted along the edges of the pools, where we found ferns (Cheilanthes covillei), rushes (Juncus acutus), and orchids (Epipactis gigantea) in the wetter parts of the oases.

By the end of the March weekend, the collected effort of all bio-hunters had identified more than 558 species, including more than 200 species of plants and 300 species of insects, as well as 32 bird species, 12 reptiles, seven mammals, and one amphibian species. For our part, we found many plant species that had not been documented before for this location in the Park, and at least one species that was new to the Joshua Tree park plant list.

The April Biodiversity Hunt at Smithwater Canyon focused on one of Joshua Tree National Park’s richest areas for plant diversity, due to its higher elevation, perennial water flow, and steep canyon walls that form diverse microhabitats for plants, as well as its location in the transition between the Mojave and Sonoran deserts. We were fortunate on Friday to be joined by Tasha La Doux, a Ph.D. graduate of RSABG’s program, who now divides her time between Joshua Tree and the Sweeney Granite Mountains Desert Research Center in the Mojave. We were also joined by Darryl Slate, an enthusiastic and knowledgeable amateur botanist who lives near the park. In our two day hunt at Smithwater Canyon we found 160 species of plant, both common and rare species, as well as contributing the sole sighting of a speckled rattlesnake to the reptile list. Due to the dry spring in the desert, the abundance of spring annuals has been quite modest throughout the Park, resulting in an under-representation of total plant diversity.

Earth’s biological richness belongs to all of us. A deep appreciation of the biodiversity of a place can stem from an understanding of the geological and biological history of that place, and can also help the human population of the planet deepen its connection to the other species that share their piece of the planet. We hope, also, that encouraging people to know the organisms around them will deepen their caring for wild species enduring presence on Earth. RSABG’s conservation efforts aim to increase the chances that California’s flora survives intact to the world of our great-grandchildren. Field studies such as our Biodiversity Hunt participation at Joshua Tree helps this effort by assuring that we know what grows where, while also helping federal resource managers do their job effectively, by helping them to know more about the biological diversity they are protecting.

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