Radically self-reliant branchiopods stand up to all but vehicle tires
You may have heard the buzz a few days before Burning Man that the Black Rock Desert playa was infested with tiny biting bugs. By the time the festival began on Aug. 29, the bugs had subsided, but what few playa-goers realized was that they still didn’t have Black Rock City entirely to themselves. Just millimeters below their feet, the eggs of countless tiny playa critters—branchiopods—lay dormant in the dust.
Though the playa appears barren and lifeless in late summer, it floods during wet winters, forming a shallow lake. During that time, branchiopods (pronounced bran-kee-o-pods), crustaceans common to desert environments of the West, quickly grow, reproduce and lay eggs.
When the lake dries, tiny eggs remain in the ground until the next flooding—sometimes years later. In the meantime, they must withstand extreme conditions—strong winds, heat, cold, and maybe worst of all, vehicle traffic. The eggs are fragile and can be crushed by a car (or truck, or RV, or dragon-shaped art car). In 2013, Desert Research Institute scientists Don Sada, Chris Rosamond and Ken Adams published a study documenting the effects of vehicle traffic and Burning Man activities on branchiopod egg survival.
During the study, the team visited the lake in a kayak during flood conditions, found four species of branchiopods. The most common were the giant fairy shrimp (Brachniecta gigas). “They can be about this big,” Sada said, holding his fingers about 3 inches apart. “They swim upside-down, their legs pulsate. They’re real flowy in the water, they look like little fairies. They zoom around. They’re just beautiful.”
The team collected egg samples of eggs before and after Burning Man, in roads and camping areas. They found egg survival was worse in camping areas (50 percent fewer surviving eggs) than on roads (30 percent fewer). Sada suspects that the difference has to do with water trucks. Under natural conditions, when the playa dries after a flood, the surface hardens, providing a layer of protection for the eggs. Over time, the playa becomes softer and dustier, offering less and less protection. Something similar may be happening inside Black Rock City.
“I think what happens is that they go by with a water truck a couple of times per day, and it hardens [the road surface], Sada said. “Those roads are hard, but the camping areas get fluffy. That’s where I think the eggs get damaged, because they aren’t protected by the crust anymore.”
Branchiopods are discussed several times in the Bureau of Land Management’s 343 page Environmental Assessment for Burning Man. Under a proposed alternative for the 50,000-70,000 person crowd, the BLM recommends that the corporation operate up to 14 trucks to keep the roads wet during the event, both for dust control and protection of branchiopods. After the event, the BLM recommends that BRC soak the playa surface with water to create a protective crust.
Sada believes that branchiopods are affected by Burning Man, but doesn’t think that it has a significant impact on the overall population because the event has a relatively small footprint, occupying only about 3 percent of the 1,000 square mile playa.
“I’m almost thinking that the smaller raves throughout the summer might have more impact than one big one, just because it’s a more widespread disturbance,” Sada said.