RESTORING ROCKWEED: LOOKING FOR A ‘FIGHTING CHANCE’
For beachgoers, rockweed may be a nuisance to be avoided either on the shore or in the water.
But for species other than humans, the alga plays an important role in life.
For UCSB marine scientist Robert Miller, rockweed is considered a foundation species, providing “a nice damp habitat that enables other species to survive where they otherwise would get dried out and exposed to the sun and die.”
Unfortunately for the species using the alga as a habitat, the California coast has witnessed a decline in rockweed over the past five decades.
“That decline seems to be due to various factors, including drying out from the Santa Ana winds, trampling by humans during low tides and, potentially, pollution,” Dr. Miller said.
Organisms that claim rockweed as their habitat include limpets, crabs, barnacles and snails. Sometimes when the tides are high, fish may even join these organisms.
With the decline of rockweed, unfortunately, the coastal biodiversity also decreases, which means less limpets, crabs, barnacles, snails and fish in the area.
Dr. Miller and his team are moving to slow and possibly reverse the rate at which the seaweed is declining. The team pools researchers from several institutions across the state: UCSB, UCLA, Cal Poly Pomona and UC Santa Cruz. Team members will resettle rockweed from where it in plenty to areas where it is scarce. The multi-institution team will identify which regions along the coast needs restoration, find nearby locations that have abundant rockweed, and transfer it.
This process, however, will pose some difficulties.
“The challenge,” Dr. Miller said, “is that each plant it very used to the spot where it’s growing.”
A UCSB doctoral student, Stephen Whitaker, agrees.
“Unlike many other marine organisms, which broadcast their progeny into the water column to be subsequently transported from their origins via ocean currents, rockweeds release gametes during periods of low water motion,” said Mr. Whitaker, who will be bringing his expertise of a certain rockweed species, Silvetia compressa, with him onto the team for the project.
Mr. Whitaker is describing the reproduction mechanism of the rockweed, which “can result in high levels of genetic difference between populations.”
Mapping the data on rockweed along the California coast could be daunting, but luckily for Dr. Miller and Mr. Whitaker’s team, technology is on their side.
“One of the elements of our project is to map each donor and recipient site with a drone,” Dr. Miller said, “to try to match the tidal height as close as we can when we transplant a plant from one site to another to make sure it’s in a similar habitat.”
The drones will fly at about 40 meters above the water, an altitude that will allow them to capture high-resolution data and multispectral imaging over the coastline.
The data collection does not end there. Paige Miller, a geneticist at UCSB’s Marine Science Institute, will conduct genetic testing to keep track of the rockweed genotypes in a region.
“Our hope is that restoring some of these populations may bring them back to the point where they can recover,” said Dr. Miller. “Not every plant will succeed, but we need to give this species a fighting chance to endure.”
The restoration project is in its initial stages and the team is gathering permits.