The Colorado River snakes through seven states before crossing the Mexican border. Along the way, it’s held back by dams and distracted by reservoirs and wetlands. Depending on the season and the location, it alternates between cold, muddy and rushing or warm, clear and slow.
But the most complicated component of managing the river? The people.
“The program I work for is a partnership of 10 entities that includes state and federal organizations, environmentalists and water users,” says Kevin McAbee (MS ’08), nonnative fish coordinator for the Upper Colorado River Endangered Fish Recovery Program. The program oversees and coordinates the recovery of four endangered fish in the Colorado River north of Lake Powell. “So, in order to be able to enact meaningful conservation actions for species that can swim hundreds of miles in a year, you have to have buy-in that bypasses state boundaries; you have to do things on a big scale.”
McAbee is one of many graduates of the UGA Warnell School of Forestry and Natural Resources working to help animal species around the world survive—and thrive. But whether it’s the humpback chub population in the Colorado River or mountain gorillas in the Democratic Republic of Congo, the balancing act alumni face often has more to do with human effects on the ecosystem than other animals or Mother Nature.
On the Colorado River, what turned the tide for humpback chub, Colorado pikeminnow, razorback sucker and the bonytail involved changing the timing of dam releases to change the flow of the river. The four species, all classified as endangered, are native to the Colorado River Basin, but during the last century, new dams and changes in water use disrupted their ecosystem.
By enacting conservation methods such as adjusting water releases, habitat restoration and manually controlling invasive species that prey on the native fish, McAbee says, the multi-state and multi-agency partnership is making gains. But along the way, the partnership must also weigh the needs of landowners, municipalities and visitors on the waterways.
On the Colorado River, a combination of management techniques have helped the four species make a turnaround. Some fish are propagated at a hatchery. McAbee and his team work to improve and restore habitat along the river. They also manage nonnative fish species that prey on them.
But the timing of water releases from the dams was a game-changer, he says.
“We have worked with the dam operators to change the release from the dams so it’s a more natural water regime. And that’s a big action because it has legal and political impacts—we’re changing the way dams are operated so they benefit fish, and that’s a really big deal,” says McAbee. “We recently completed a status assessment for the humpback chub, and the Fish and Wildlife Service recommended that we reclassify it from endangered to threatened. And that’s related to the dams and the change in the flow regime.”
The biggest threats to the native fish are three nonnative species: smallmouth bass, northern pike and walleye. They are voracious predators, and because it takes the native fish between 3 and 10 years to reach sexual maturity, the nonnative species eat the native ones before they have reached that point.
Originally stocked in reservoirs for recreational fishing, nonnative fish escaped through dam outlets, entered the river system and slowly began to take over. The changes McAbee and others have implemented increase floodplain habitats, giving the fish a place of refuge after emerging from their eggs in the spring. They grow up fast over the summer and enter the river in the fall, successfully making it through their first difficult summer.
Julie Stahli (MS ’08), deputy director for the Upper Colorado Endangered Fish Recovery Program, says it’s been a learning process for all parties involved. Once they began to understand the role that wetlands and upstream inlets played in the overall success of the fish, they incorporated management of those areas for even greater success.
“Many efforts had been made with wetland habitats in sort of varying stages over the course of the program, and what they figured out was they not only had to flood the area during dam releases, but they also had to screen the wetland so no nonnative predators got in with the larvae,” she says. “Another key piece was building wetlands with downstream inlets, instead of on the upstream side so water backs in to the wetland. It allows larvae to come in and it doesn’t fill it up with sand.”
In the past year, the river saw high water flows in the spring, resulting in larger wetland areas. This provided more habitat for razorback sucker larvae, increasing their overall number. Scientists have also seen a marked increase in the number of razorbacks in one of the systems’ lakes, where previously they weren’t notable.
Whether McAbee, Stahli and others have found a balance or the right formula for fish success is only part of the story, though. Bottom line, they say, the river can’t not be managed.
“The system has gotten so complex and there are so many stressors on the species that there’s really no way to not manage them anymore,” Stahli says. “The program we are lucky enough to work with has been built up over the years by dedicated partners. It’s always invigorating to hear how power customers and wildlife biologists and others want the same thing, which is how can we get species to survive and thrive in this ecosystem.”
“Things that we have done and that our partners have done have had an effect where we’re less concerned with the species going extinct immediately,” he says. “We still have some conservation commitments that we need to look at in perpetuity, but certainly a lot of actions we’ve enacted have worked. It’s a big success story in the Colorado River System.”
A tortoise tale
Not far from Aiken, South Carolina, is a swath of land bordered by red-dirt roads and dotted by longleaf pines. This is where, in the early 2000s, South Carolina wildlife officials discovered about 10 gopher tortoise burrows. More plentiful in Florida, you can find a few other populations scattered across the South—but not typically in South Carolina.
The discovery of the burrows was significant, and it started the state on the path of habitat conservation that’s turned into a long-term project in collaboration with the University of Georgia’s Savannah River Ecology Lab to maintain and increase the preserve’s gopher tortoise population.
Andrew Grosse (BSFR ’06, MS ’09), herpetologist for South Carolina’s Department of Natural Resources, says the Aiken Gopher Tortoise Heritage Preserve is home primarily to waif tortoises—animals from throughout the species range that have been removed from the wild, due to a variety of circumstances, and can’t be traced back to their original population. When these animals are received by the Department of Natural Resources, they are initially quarantined at the Savannah River Ecology Lab, where they receive a health examination, food, water and short-term housing. After being cleared for release, they are added to the population at the preserve.
But, you can’t just take gopher tortoises and drop them into a new landscape—they tend to wander and search for familiar landmarks. In fact, the lack of a consistent network of land where they can roam is one of the largest threats to the population.
Grosse and the state Department of Natural Resources have been working with Tracey Tuberville and Kurt Buhlmann, conservation scientists at the Savannah River Ecology Lab and Warnell faculty, to release the animals into a cordoned off area for the first year on a new site. Research conducted by Tuberville found that after about a year in the large pen, about 80% to 95% of tortoises would stay in that area. This is key in creating a viable population at the preserve.
“If you release tortoises on a new landscape, they are disoriented,” says Grosse. “But once placed in a multi-acre pen, they get familiar with the surroundings for a year. Over that time, they become more comfortable and establish a social structure with the other penned tortoises. After a year, we take the walls down and the tortoises are free to roam.”
In a study similar to Tuberville’s, graduate student Rebecca McKee found high adult survival of penned and released waifs. As a student of Tuberville and Buhlmann, McKee’s thesis research, conducted at the gopher tortoise preserve outside Aiken, also found that more than 75% of the penned tortoises were recaptured within 400 meters of their original release location in the pen, further supporting Tuberville’s research.
The preserve is also home to “head-started” tortoises. Tuberville and Buhlmann collect naturally deposited eggs on the preserve and hatch them at the Savannah River Ecology Lab. There, they grow indoors through the winter and are fed a healthy diet. They are released one year later at a larger size than their wild-raised siblings and presumably less vulnerable to predators. The hope is that this effort will increase their survival into adulthood.
Habitat restoration and management, says Grosse, is the single most important factor for the long-term success of the animals.
“It takes multiple partners to accomplish these projects. Our land managers do an excellent job of managing our properties to promote the longleaf pine ecosystem,” says Grosse. “Coupled with our partnership with the Savannah River Ecology Lab, we’ve been able to make a positive impact for gopher tortoises and all the species that use the longleaf pine ecosystem. For me, it’s really exciting and just makes me proud to be part of this group.”
Conservation is also a key component to the work done by Jena Hickey (PHD ’12), a conservation scientist with the International Gorilla Conservation Programme (IGCP). Her work takes her to the Democratic Republic of Congo, Rwanda and Uganda—the three countries in the world where mountain gorillas live—where she’s part of a team that monitors habitat conditions and gorilla populations.
The gorillas live in two large, unconnected populations surrounded by an ocean of agriculture. Local farmers are dependent on crops for their income, but if they grow food that both humans and gorillas can eat, issues arise.
“It’s a cash-poor society and they really need their crops. If mountain gorillas or any other species leave the protected areas and start raiding crops, it’s a major concern for those populations,” she says. “So, our goal with IGCP is to address human-wildlife conflict through vegetation management—what can we grow in a buffer zone between the parks and the rest of the human community to reduce how often gorillas leave the parks?”
For example, growing tea instead of vegetables can help discourage gorillas from foraging through the fields, improving relations between gorillas and local residents.
“A lot of times, what IGCP does is to get stakeholders talking about the problems and the solutions — and the process often helps align the stakeholders to a common set of goals,” adds Hickey. “IGPC also tries to create direct community benefits from gorilla conservation.”
Revenue-sharing is one way residents can benefit from ecotourism. A one-day trek to watch gorillas in Rwanda costs tourists $1,500, while the average daily income in nearby communities is just a few dollars. By funneling some of the gorilla-tourism money into the local economy, says Hickey, it can help change attitudes toward the animals, the parks and conservation.
Poaching and the hunting of other wild animals also threatens gorillas. Forest antelopes, called duikers, are often hunted with snares. When gorillas get caught in these traps, the result can be a lost digit, a limb or even death, says Hickey.
Overall, though, she says the progress made toward mountain gorilla conservation has been a success. The population has approximately doubled from its lowest point in the 1980s, when there were between 300 and 400 gorillas. But even if the population were to continue to grow, the size and location of the parks will likely limit the overall number of gorillas. Climate change is also a concern, because as the cooler temperatures of the mountains warm, vegetation will surely shift, which may impose further limits to the mountain gorillas’ range.
One option is to increase the size of the parks, but that would mean taking land out of agricultural use—a hard sell among the local population (or, really, any population of landowners).
“It’s a super sensitive topic, and it has to be a procedure that really fairly compensates them if they are willing to move,” she says. “Let’s say it went perfectly smoothly and habitat was rehabilitated in that area—it’s still not that much more habitat. So, from the perspective of a population ecologist, how many more gorillas are we going to get out of that?”
Above all, the graduates say their time at Warnell gave them essential skills that are used in their jobs today, and also helped them identify the human aspects of conservation.
For example, as a doctoral student, Hickey traveled to Congo to work with bonobos, another great ape. Using the capture-mark-recapture population abundance estimation method she learned in professor Mike Conroy’s class (now retired), as well as another technique called sight-resight, she and colleagues developed new approaches for how to estimate abundance.
Learning the new languages and understanding the field conditions were also key parts of her training.
While Grosse’s first experience with gopher tortoises came immediately after graduating from Warnell, where his job at the Savannah River Ecology Lab was tracking the very first group of penned tortoises, his work also incorporates landscape management—a skill learned at Warnell. Whether it’s burning or mechanically thinning trees, he now stresses to landowners what he learned as a student: The benefits of properly managing a landscape.
“Students say, ‘I really want to save X.’ But we need to think about it from an ecosystem standpoint,” adds Grosse. “All these things have adapted together and are living together. Even if they’re not on the landscape at that time, there are other species that it benefits.”
Before she started at Warnell, Hickey said she was surprised by how human-centric the work really was.
Now, though, it all makes sense.
“I feel like it’s a no-brainer now. It’s because of us that the habitats have become fragmented or there’s fewer cover types. That’s because of our footprint on the world,” she says. “And that’s probably a message we need to get to our undergraduate populations. Humans will be a major part of your work if you’re a wildlife biologist. It’s just reframing the problem.”