In the summer’s intense Mojave heat six people strained their eyes against dust and brilliant sun, seeking signs of vegetation in tortoise territory. Walking for miles across the desert, they carried sampling frames, GPS units, and vital liters of water, all to assess the devastating effects of wildfires on the habitat of the threatened Desert Tortoise (Gopherus agassizii). Research Assistants for the Great Basin Institute, this team of explorers spent eight months in the wide open spaces of southern Lincoln County, Nevada, a region of mostly public lands managed by the Bureau of Land Management (BLM).
When the 2005 wildfires swept through the northeastern Mojave Desert four years ago, an unprecedented 787,414 acres of protected and grazed land burned. Many species, some threatened like the desert tortoise, some introduced like cattle and sheep, were affected by the fires. Already scarce food and cover plants vanished. Several seasons following the fires, what was the condition of plant resources for desert tortoises in the burned habitat? As part of its mandate, the BLM rehabilitates degraded lands. An effective desert recovery management plan called for systematic data collection and assessment. Enter, stage right, GBI’s vegetation research team.
Orchestrating this complex data collection project took expertise, planning, and tenacity. GPS units in hand, the team zeroed in on all 81 sample sites chosen for study in burned, unburned, grazed and ungrazed areas. Next, they pounded stakes into the bajada—ground characterized by hard-packed gravel—to mark each and every site, some just meters off the road, others a mile’s walk or more. As summer temperatures ramped up, cresting 115 degrees, already remote sites seemed, like mirages, beyond reach. Still the team persevered. Measuring tapes were unfurled into huge rectangles. Plant numbers and species within each sample site were systematically recorded. Not far from the main rectangle, an even longer tape measure was extended. At ten meter intervals along this tape sampling frames were placed over plants, which were then carefully removed, weighed, and stowed for reweighing. Shrubs were also measured and counted, and the sparse cover they provided—or, more often, didn’t—was recorded as the gap between woody plants—or their charred remains—on data sheets. Yet, after taking all of these vegetation measurements at each sample site, the crew’s work had hardly begun.
The six spent hours entering data into spreadsheets, weighing dried plant matter, labeling and processing the photographs they’d taken at each site, and identifying “mystery” plants using classification keys. Quality control
came next: each data sheet was checked against its digital counterpart; each photograph was scrutinized; each bag of forbs was weighed, and weighed again, for accuracy. And when all these steps were completed? Restocked with supplies, the team returned to the desert. In order to capture vegetation structure data three times during the desert tortoises’ activity season—spring to fall—the team repeated each step in this rigorous sampling process not once, but twice more.
After a long summer in the Mojave, an accurate and complete data set was delivered to the BLM by a satisfied and weary field crew.
During the 2009 season, the vegetation crew spotted and photographed eight desert tortoises, repaired 24 flat tires, witnessed the destruction of three shade structures by the Mojave wind, and extracted countless cholla spines from clothing, backpacks and bare skin. The six researchers emerged otherwise unscathed from a scorching field season in the Mojave Desert, awestruck by the desert tortoise’s persistence in this challenging landscape, and hopeful that their efforts will help the tortoise endure.
By Sedona Maniak, GBI RA – Crew Coordinator, September 2009