Why Remote Parks Suit Long-Term Ecosystem Research, and What Stands in the Way

Remote parks let scientists study ecosystems where the human imprint is faint, and the data from such places are scarce and therefore valuable. Robert Stottlemyer, writing in Alaska Park Science, draws on watershed studies begun in 1980 at Isle Royale National Park in Michigan and in 1989 at Noatak National Preserve in Alaska. Stottlemyer argues that long-term studies in remote parks likely offer the best remaining chances to record baseline ecological conditions, and that the Park Service seldom pays for that kind of work.

The small-watershed idea

Since the 1930s scientists have known that ecosystems have budgets of energy and nutrient inputs and outputs, with nutrient supply the factor that limits biological growth most. But without understanding the internal processes that move and transform nutrients and energy, it was hard to separate and measure the effects of regulating processes such as human activity. By the 1950s an ecosystem model had been developed in which the major quantities could be measured directly in the field. By linking hydrology with other ecosystem processes, this small-watershed model allowed biogeochemical cycles, the movement of nutrients and energy between the living and nonliving parts of an ecosystem, to be quantified.

Two boreal sites

The first long-term site is the Wallace Lake watershed in Isle Royale National Park, in Lake Superior. About 99% of the park is wilderness, it is one of the least visited national parks, and it can be reached only by boat or float plane. It lies along the southern edge of the boreal forest where it meets northern hardwood forest. The boreal biome covers 32% of the world's forested area, second only to tropical forests, and about 20% of national park land is boreal, yet the biome is little studied for its global importance.

Noatak is one of the few park units whose enabling legislation, the Alaska National Interest Lands Conservation Act, names research as a priority. It offered a chance to study the northern treeline, where boreal forest gives way to tundra, and compare it with the southern edge at Isle Royale. Such transitions, where many species are at the limits of their range, are especially sensitive to stress. One Noatak study site is the 1,980-acre Asik watershed in the south-central preserve, which drains into the Agashashok River and is half covered by white spruce. Another lies along the Kugururok River, just north of where it meets the Noatak River, at the northern edge of treeline, in a region characterized as cold desert, with less than a foot of precipitation a year and discontinuous permafrost.

The research emphasizes what happens below ground: physical, chemical and biological processes and the diversity of microbial functions. More than 99% of an ecosystem's biodiversity usually lies in the subsurface layers, and as much as half of its production can occur there, mostly as microbes and small roots. The below-ground community therefore controls the quality and quantity of most nutrients and almost half of the energy available to life above ground.

What remote sites can show

• Benchmarks that cannot be redone. The predator-prey studies on Isle Royale, begun in 1951, have helped refine conceptual models of predators and prey. Such studies cannot be repeated because suitable sites are lost, and new ones cannot recreate the detailed changes that have already happened.
• A nitrogen puzzle. In the lower 48 states, one hypothesis says that where human activity raises atmospheric deposition of dissolved inorganic nitrogen (DIN), stream nitrogen should be mostly that DIN rather than dissolved organic nitrogen, which points to processes on land. In Alaska, atmospheric DIN deposition is low, less than 0.3 kilograms of nitrogen per hectare per year, about 5% of the Isle Royale figure, yet stream nitrogen is dominated by DIN. That sent investigators looking for why treeline and taiga ecosystems lose this nutrient when so little arrives from the air.
• Tracing pollutants. Substances tied only to human activity, such as polychlorinated compounds, are easier to trace when they turn up cycling where they were never used. A study of Siskiwit Lake at Isle Royale documented past and present cycling of dioxins and furans where the atmosphere could be the only source, and studies like it prompted widespread monitoring for these compounds in the Arctic and Antarctic.
• Simpler ecology. High-latitude sites tend to be ecologically simpler. On a river terrace next to the Asik watershed, the depth of the silt and sand cap above the gravel floodplain strongly shaped which plants grew, how much they produced and how they responded to change.

Climate and the soil

The author thinks one of the most valuable things protected remote sites can do is document the effects of global change, mainly climate. In Alaska these studies are driven by the rapid change in temperature and moisture in taiga and tundra regions, though that speed also weakens them, since there is no baseline for the processes they track. High-latitude ecosystems hold about a third of the world's soil carbon as organic matter, and at the Noatak treeline most of it lies below the annual thaw depth, out of reach of living things. Anything that deepens the soil's active layer would change soil temperature and moisture, decomposition, soil respiration and nutrient availability, and the increase in mineralization would eventually realign biodiversity below and above ground.

The author also sees the growing season stretching into autumn. At Asik, air temperature peaks in June, but soil temperature peaks in late August or early September, which lets carbon and nitrogen mineralization continue after plants have slowed their uptake. That likely explains the high dissolved organic carbon and nitrate in late-summer stream water, nutrients and energy for the base of the aquatic food web, and it will likely alter that food web's biodiversity.

The obstacle

Remoteness brings logistics and limits on research, especially experimental design and monitoring quality. National parks are seldom used for long-term interdisciplinary research partly because data gathering in busier parks is aimed at specific management issues, which carefully designed long-term studies rarely suit. Yet baselines matter more as the economic value of ecosystem services is better appreciated, the author says. Such work is hard to justify because immediate issues crowd it out, many of them caused by a lack of basic understanding of how ecosystems function through time, which in turn comes from little commitment to anticipatory science. The Park Service's opportunity, in the author's view, is to support and take part in sustained study, and its obstacle is a short-sighted view of the information it needs to care for public lands.

Sources

• Robert Stottlemyer, Long-term research in remote parks: Opportunities and obstacles, Alaska Park Science, issue The Legacy of ANILCA, National Park Service; rewritten in hubnx's own words.