|Dennis Whigham and his team plodded through pristine areas of the Kenai Penninsula to reach their study sites.
This story first appeared in the SERC quarterly Newsletter Fall 2006
Bushwhacking for Salmon's Sake
Though the hiking was rough and the terrain unyielding, there was at least one literal bright side to the 19-hour days Deputy Director Dennis Whigham spent doing field work in Alaska this summer: the sun never set.
Whigham and his colleagues from Baylor University and the Alaska Fish and Game Department bushwhacked through the pristine wilderness of Southern Alaska's Kenai Peninsula with the goal of surveying fish and wetland species within an 810,000 acre wilderness that covers five different rivers. The researchers intend for their work to help Alaskan land managers determine what types of wetlands and headwater systems are needed to support a healthy salmon population.
Alaska's economy thrives on salmon. The commercial harvest was valued at $305 million in 2005. Recreational fishing brings in even more revenue during salmon runs, when salmon return from the ocean to spawn in their natal streams. In 2001, Alaskan fishing trips represented $537 million to the state's economy. While many Alaskan salmon runs are endangered, the Kenai peninsula run remains healthy. But most of the land is privately held, and a 20 percent increase in residential growth in the Peninsula over the past 10 years raises concerns that development may encroach on wetlands and streams affecting salmon populations.
Stream headwaters are known to exert a strong influence on downstream physical and chemical water properties. They are also known to provide critical habitat for young salmon, but a comprehensive survey identifying the specific wetland characteristics associated with a healthy salmon population had not been done in the Kenai Peninsual before.
Understanding what streams and wetlands are most important to preserve in such a large area, however, is not a simple matter. Whigham has experience with this type of daunting issue as one of the lead scientists of the Atlantic Slope Consortium project (ASC). The basic premise of this six-year-long study was that everything about a piece of land draining into a body of water—its shape and size, its geology, the plant and animal communities that live there, and the land use practices of people—has potential to influence what goes on in the water.
By synthesizing information from ecological and socio-economic surveys across small watersheds and estuary segments, the ASC team was able to identify key factors and combinations of factors that influence watershed health and the health of downstream aquatic ecosystems. From that knowledge, they developed a set of indicators to assess ecosystem health and sustainability over large scales such as the Chesapeake Bay.
Recognizing an opportunity to expand the tools and skills developed during the ASC project and apply them to the vastly different environment of Alaska, Whigham contacted his former post doctoral fellow Ryan King who had worked on the ASC and is now an assistant professor of biology at Baylor University in Texas. Together, they set out to conduct the Alaska project. The scientists looked for intersections of different wetland types and streams in the area. They plotted coordinates from a Geographical Information Systems map into a hand-held GPS device, and then selected potential sites to survey.
The scientists set out to survey 40 streams in settings with different geomorphic profiles. Dividing into teams, they canvassed the area on both sides of each stream to characterize the physical conditions over a distance of 250 meters. The wetland team developed a vegetation map and sampled herbs, shrubs and trees in sample plots and collected water for nutrient analyses. The fish team surveyed the fish and invertebrates within each stream. The work was intensive and the very nature of the Alaskan wilderness meant the work was almost always challenging.
Throughout the six-week survey, the group faced close encounters with black bear, a grizzly that startled at the approach of their jeep, and fiercely protective female moose and their young. But the most arduous aspect of the work was the sheer effort it took to get to their sites.
Team members report taking more than an hour sometimes to advance one mile over dense thickets of willow and fallen spruce trees. At 62, Whigham was grateful he had spent months preparing for the trip—hiking with a 35-pound backpack two or three times a week, biking four to six hours per week and climbing ten laps or more up and down SERC's 125-foot research tower three or four times a week during his lunch break. Still, he reports losing 40 pounds on the expedition.
The group sampled 30 streams and found juvenile salmon in many of them that had never been documented before. "We've clearly demonstrated that the tiny streams are supporting juvenile salmon," Whigham said, "Why in some streams and not in others? Those are some questions that we still have to answer."
The scientists hope to continue their work in Alaska, but for now, the summer has provided them with a vast amount of data to synthesize. Their report promises to tie key environmental features and conditions to the sustainability of one of Alaska's most valuable resources, the salmon. "When [resource managers] have that information," said King, "they can start identifying priority areas for conservation in developing management plans that protect these headwater streams, because right now there's very little protection for them. It's not uncommon to see someone clearing land right up to the edge of these streams or even pushing soil into them, which obviously has major implications for juvenile salmon."
"Salmon is our life and economy," said Coowe Walker, a watershed specialist with Alaska's Kachemak Bay Research Reserve and coordinator for the research. "This project is key to developing our understanding of headwater stream habitat. Most runs of salmon [in Alaska] are endangered, but we [in the Kenai Peninsula] have a healthy run of salmon, and we want to keep it that way."
—Portions of this story were adapted from an article by Matthew Waller in Baylor Magazine.
For more information, or to reach Dr. Whigham, please contact SERC science writer Kristen Minogue.