High elevation recreation presents a complex dimension to the management of mountain ecosystems. Results of our recent economic study indicate that recreators place approximately four times the value on high elevation recreation than on "typical" mountain recreation experiences. These findings imply that there are limited substitutes for high elevation recreation, and a high demand for such experiences could tax the environmental carrying capacity of the fragile tundra.
The Niwot Ridge (NWT) LTER site was one of the five original LTER sites established in 1980. The LTER program is based at the University of Colorado-Boulder and is administered through the Institute of Arctic and Alpine Research (INSTAAR) and in cooperation with the Mountain Research Station, with special use permits from the US Forest Service.
Large-scale climate features such as sea level pressures and sea surface temperatures have been shown to influence streamflows in regions around the world. We examined the influence of such features on total annual flows in a summertime glacial meltwater river, the Onyx River, in the ice-free McMurdo Dry Valleys, Antarctica. The 38-year Onyx record is the longest flow record for the continent. The study focused on the December-January climate features.
Determining organic matter sources to CH4 production and bubbling from Alaskan lakes using stable isotopes and radiocarbon ages
Methane production in Siberian thaw lakes is estimated to be 3.8 Tg CH4 yr -1. When entered into global models, this estimate increases northern wetland CH4 emissions (<6-40 Tg CH4 yr -1) by 10-63% (Walter et al 2006). Methane release of this magnitude from Siberian and other northern lakes, such as those in Alaska, may be linked to the rich carbon resources available to sediment-dwelling methanogens.
Arctic warming has been linked to changes in carbon cycling in this region. Cold temperatures and anoxic conditions in the Arctic inhibit microbial activity, lowering decomposition rates. As a result mineralization rates are low, resulting in nitrogen-limited-system, further reducing biological activity. Evidence has shown that eliminating this constraint on nutrient availability results in a vegetation shift and loss of soil carbon; however, the mechanisms behind soil carbon loss are not understood.
Lake ice seasonality (freeze day, breakup day, and ice duration) is closely related to climate change and variability. Trends and changes in variability and extreme events are apparent. The shared variance between mean anomalies of ice duration and Northern Hemisphere land air temperature over the last 150 years is r2 = 0.47. Mean trends are in the direction of warming. Ice duration has the steepest decline with mean trends (days/decade) of 1.7 over the last 150 years, 1.1 over the last 100 years, and 6 over the last 30 years.
Soil temperature is one of the key determinants of carbon flux, nutrient availability, decomposition rates, and primary productivity in high-elevation and high-latitude ecosystems. Global climate models predict that as air temperatures rise there will be a corresponding increase in soil temperature and a longer snow-free season.
Using Webb gliders to study the physical regulation of ecosystem dynamics at Palmer Station Antarctica
A Webb Slocum glider was launched on Western Antarctic Peninsula (WAP) launched out of the U.S. Palmer Research Station. The glider mission covered >600 km, providing >1400 ocean profiles. The glider profiles, in combination with Adélie penguin foraging data (from penguins tagged with ARGOS-linked tracking instruments), showed that Adélie penguins in the area of Palmer station forage just at the base of the chlorophyll maximum, which may provide improved visibility for these visual foragers.
Antarctic seabirds, including Adélie penguins (Pygoscelis adeliae), south polar skuas (Catharacta maccormicki) and southern giant petrels (Macronectes gigantus), are high trophic level predators that accumulate persistent organic pollutants (POPs) present in the marine food webs in which they forage. Diet and migration patterns influence the level of POP residues per species. Here we examine POP levels within the three bird species based on migratory patterns and trophic level using stable isotope analysis of δ15N and δ13C.
The International Long-Term Ecosystem Research network (ILTER) includes national networks of scientists and their stakeholders engaged in long-term, site-based ecological, social and economic research. The LTER-Italy network, established in 2006, joined ILTER in 2007. The “Apennines (high elevation)” site joined LTER-Italy in 2007. It consists of “orographic islands” of alpine tundra along the Apennines chain, where many endemic and rare taxa occur that are critically endangered by climate warming.