Science Spotlight

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  • July 26, 2019

Small brown rodent on white background
A tagged Amargosa vole. (National Geographic stock photo)

Group of three people wearing hats standing in dirt and cut grass next to large cage made of chain link fence in grassy area.
The “soft release structures” built for the voles were constructed in their natural habitat, giving the captive-bred animals time to adjust to the outdoors. (Photo courtesy of UC Davis School of Veterinary Medicine)
 

Wildlife veterinarians recently hit an important milestone in their collective efforts to conserve a tiny endangered mammal native to the Mojave Desert. The population of Amargosa voles (Microtus californicus scirpensis), restricted to one small town in Inyo County, is now perilously small, due to habitat destruction, climate change and water diversions created to benefit humans. With much of the voles’ natural habitat now decimated, scientists estimate that fewer than 500 currently exist in the wild. (Read the original California Department of Fish and Wildlife Science Spotlight on Amargosa voles).

Co-led by CDFW Wildlife Veterinarian Dr. Deana Clifford and UC Davis Veterinarian Dr. Janet Foley, the Amargosa vole recovery program started in 2012. After the population became nearly extinct in 2014, a captive breeding program was launched at the UC Davis School of Veterinary Medicine as a last-ditch effort to save these tiny creatures, which are a key link in the food chain in their native habitat.

Since the breeding program’s inception, 364 voles have been born and weaned. Several small-scale trial releases have been attempted over the last few years, leading the scientists to identify a clear problem: the animals raised in captivity didn’t necessarily know how to behave in the wild. “The colony animals were a little pampered,” said Foley, referring to the first few trial releases. “They didn’t seem to have the skills to thrive on their own.”

So how to teach a pampered vole to fend for itself? The team members tried several approaches, finally solving an important piece of the puzzle last month. The key was to introduce captive-bred animals to their wild counterparts – and let the former learn from the latter.

The team chose to pair six captive males from the facility at UC Davis with six wild caught females. The voles were introduced to each other for 10 days in temporary indoor cages in Shoshone Village to see which pairs appeared compatible for mating.

Once voles had established pairs, they were moved outdoors. Large dog runs were carefully constructed in their marshland, over the native bulrush that provide shelter and food for the voles. Each run was lined with hardware cloth in order to contain the voles and keep out predators (including coyotes, bobcats, snakes, numerous bird species, bullfrogs, house cats and stray dogs).

For the next 21 days, the new vole pairs continued to get to know each other. Project staff used pit tags – basically telemetry microchips – to monitor their movements and to ensure that they were thriving.

“We used an antenna array around the feeding station, which connects to a computer, so we could watch how they move,” Foley explained. “Most of the time they’re under the bulrush so you can’t see them with the naked eye … but we were amused to see that they’re really not that shy. One male built a tunnel in his natural habitat, but when staff was nearby, he would come out and look right at us before he grabbed food and went back in.”

At the end of 21 days, the kennel doors were opened, allowing the voles to venture out on their own. Foley says that the team was somewhat surprised to see that the pairs generally continued to come and go from the kennels, demonstrating a comfort level with the makeshift shelter. More importantly, at least one of the pairs produced a litter, and several of the other females may be pregnant.

At some point, the team will remove the kennels entirely, at least until the next captive release occurs, likely sometime next spring or summer.

Foley said that she views the July release as a rousing success – not just because the animals are thriving, but because of the body of knowledge the team learned from this experience. “It was really important for us to learn that the colony animals could learn survival skills from their wild counterparts,” she explained. “It was a gamble, and the fact that it worked is so exciting.”

The team will continue to use this technique for the foreseeable future. Ultimately, the goal is to create sustainable populations of Amargosa voles in several different areas. “If there’s a big fire, it could wipe out every marsh in the area,” Foley says. “Our work – and the techniques we are working to perfect -- will help ensure their survival.”

The captive breeding program is one part of a larger joint effort between agencies, universities and nonprofits to save the Amargosa vole. “Together with our partners at the US Fish and Wildlife Service, BLM, UC Davis and UC Berkeley, Shoshone Village and the Amargosa Conservancy, we are conducting habitat restoration, translocations, genetics and health monitoring and community engagement,” Clifford added. “What we’ve learned here not only helps voles, but also helps conserve the other species that rely on these fragile desert marshes.”

Photos Copyright UC Davis School of Veterinary Medicine. Top Photo: One of the recovery team staff members monitoring the vole’s outdoor enclosure during the introductory period. (Photo Courtesy of UC Davis School of Veterinary Medicine)

Media contacts:
Kirsten Macintyre, CDFW Communications, (916) 322-8988
Trina Wood, UC Davis Communications, (530) 752-5257

 

Categories: Wildlife Research
  • July 18, 2019

Three urchins attached to kelp various kelp stalks underwater. Urchins cover large rock in background.
Purple urchins grazing a desolate kelp forest, Fort Ross, 2015. (Photo credit: A. Weltz)

Several urchins clustered together covering large rock underwater with kelp stalk
Purple urchins consuming bull kelp fronds and stipes and crowding out native red urchins and abalone.

Several urchins and single abalone attached to kelp stalks underwater with large rocks in background
Unusual photo of abalone and purple urchins consuming bull kelp stipes. (Photo credit: A. Maguire)

Several urchins and single abalone covering large rock underwater
Large aggregations of purple urchins are wiping out kelp forests, creating pink barrens and out-competing other species, such as abalone, for food. (Photo credit: A. Maguire)

Rocky beach along rocky cliff side with two people in background and kelp in foreground laying on rocks.
Aftermath of the harmful algal bloom: dead abalone and other invertebrates washed up on shore at Fort Ross in 2011. (Photo by N. Buck)

Abalone turned upside down
Shrunken abalone due to lack of food, October 2015. The foot (meat) of the abalone should be roughly the same size as its shell. (Photo credit: S. Holmes)

The view of northern California’s beautiful coastline has historically been pristine and breathtaking. With dense kelp forest canopies blanketing the surface of the nearshore areas and protecting the abundant rockfishes, red abalone, sea stars and red urchins that lived below, it was a healthy, natural ecosystem rich with thriving inhabitants. Unfortunately, the ocean is now changing, and this idyllic scene is no more. But California Department of Fish and Wildlife (CDFW) marine scientists, citizen scientists and grassroots groups are all coming together to help turn back time.Their immediate focus is to eradicate the ever-increasing purple urchins.

For thousands of years, canopies of thick bull kelp (Nereocytis luetkeana) could be found along the coast of northern California, creating a rich subtidal home for the many fishes and invertebrates that lived and thrived in this region of the state. Today, bull kelp forests should be the foundation of our nearshore coastal ecosystem. The floating canopy of this brown algae gives shelter to young fish and sea stars, and the kelp itself provides food for valuable species, such as red abalone and red sea urchin.

Unfortunately, with the warming and changing ocean conditions in the last few years, scientists have noticed an alarming decline in these once prolific kelp forests. Though annually variable, in the just past five years, California’s kelp forests have declined by 93%.

In 2013, a mysterious wasting disease wiped out a large portion of the local sea stars in northern and central California. As a result, purple urchin populations exploded in the absence of the sea star, their main predator.

By 2014, a large patch of warm water developed off the coast, creating a catalyst that has further changed this underwater environment. The persistent warmer sea temperatures stress the kelp forests to the point that growth and reproduction have slowed dramatically and caused damage to remaining fronds and tissue.

But perhaps the most critical effect is that the purple urchin populations now thrive without their primary predators, and are left to graze the kelp unchecked. Purple urchins feed mostly on algae (like bull kelp) with beaks so strong that they can chew on everything from barnacles to calcified algae.

Along the north coast, purple urchins are now successfully outcompeting red urchins and abalone. The purple urchin population is now 60 times higher than normal. The areas that are now overrun by sea urchins with hardly any kelp left are referred to as “urchin barrens,” a type of ecosystem largely devoid of the biodiversity that used to flourish there. Due to this abrupt change, the seafloor now looks more like an underwater desert dominated by sea urchins, with little else alive.

“To address the impacts of the massive marine heat wave and kelp deforestation on the north coast we are going to need to shift our priorities and resources and come up with creative solutions,” says Dr. Laura Rogers-Bennett, a CDFW senior environmental scientist specialist based out of the Bodega Bay field office in Sonoma County. “I am encouraged that so many people and organizations are coming together in the Kelp Ecosystem and Landscape Partnership for Research on Resilience (KELPRR) collaborative and the "Help the Kelp" Campaign to promote kelp restoration in support of our kelp forest ecosystems and the human communities that make their living from the ocean.”

These negative effects reach from the ocean to the shore. Red abalone have been severely impacted by the loss of kelp and thus lack of food, causing the abalone fishery to close until at least 2021. Sea birds and marine mammals are also feeling the effects. With fewer fish available, the birds do not have enough food to feed their chicks. Reports indicate that 80% of black oystercatcher chicks and 90% of the local cormorant chicks are failing to survive. Harbor seals and sea lions are also hungry and feeling the effects.

In an all-out effort to address this devastating ecosystem change, scientists, management agencies and citizen scientists are all joining together to do everything they can to help. Their strategy is to harvest the purple sea urchins by hand to remove them from invading all of the substrate where bull kelp resides. By doing this they hope to create a network of healthy kelp patches along the coast.

Work is underway to create kelp refuge sites in North Caspar Bay, Noyo Harbor and Albion. This urchin removal project is a massive undertaking. Scientists hope also to try to develop commercial uses of the purple urchins, thus ensuring long-term sustainable harvesting.

Watermen's Alliance, a union of spearfishing clubs throughout the state, is coordinating urchin removal events this summer along the Sonoma and Mendocino coast using recreational divers wishing to assist with the purple sea urchin removals.

Next up will be the July 27-28 Purple Urchin Removal Event on Noyo Beach in Fort Bragg. They will need as many free divers and scuba divers as possible to participate, as well as kayakers to ferry full collection bags from the divers to boats and empty bags back to the divers. Just bring your dive gear or kayak gear and a valid California fishing license if you will be a diver removing urchins.

If you dive, boat, kayak or are just interested in helping, please contact the Noyo Center for Marine Science or Josh Russo with Waterman’s Alliance at (707) 333-9575 for details.

For more information about how to get involved, and stay up to date on kelp recovery efforts, please visit the following links. There are many opportunities for involvement, whether you are a scuba diver, freediver or just a concerned community member!

  • ReefcheckCA - volunteer to help monitor coastal ecosystems
  • “Help the Kelp” Program - Noyo Center for Marine Science
  • Watermen’s Alliance - advocates for clean, productive and sustainable fisheries.
  • Urchinomics: Focused on development of a commercial market for the purple urchin

Please join us for the next installment of the Conservation Lecture Series, “The Perfect Storm: Multiple Climate Stressors Push Kelp Forest Beyond Tipping Point in Northern California” by Dr. Laura Rogers-Bennett on Thursday, July 18 from 1:00 – 2:30 p.m. Dr. Rogers-Bennett will talk about the catastrophic decline of the kelp forests and the ecosystem it supports, including the red abalone and sea urchin fisheries, and the effects of climate stressors on northern California kelp forests. Register at www.wildlife.ca.gov/Conservation/Lectures.

This lecture will be held by webcast only. Members of the public can sign up using this registration link. For more information, please contact Whitney.Albright@wildlife.ca.gov or visit the Conservation Lecture Series website.

CDFW Photos. Top Photo: Unusual foraging behavior near Elk in Mendocino County: a large red abalone climbing a bare kelp stalk trying to reach fronds that are not there. (K. Joe)

Media Contact:
Carrie Wilson, (831) 649-7191

Categories: Wildlife Research