Niwot Ridge MapThe Niwot Ridge Long-Term Ecological Research study area is located approximately 35 km (22 miles) west of Boulder, Colorado, among mountains in the Roosevelt National Forest. It is bounded on its west side by the Continental Divide. The study area was established in 1980 as one of the original six sites in the National Science Foundation’s Long-Term Ecological Research Network that has now grown to 26 sites. Located entirely above 3000 m (9800 feet) in elevation, the site represents an alpine/subalpine ecosystem and includes a cirque glacier (the Arikaree), extensive alpine tundra, high elevation glacial lakes and moraines, a variety of glacial landforms, and patterned ground and permafrost. The Niwot Ridge study area has been designated a biosphere reserve by the United Nations Educational, Scientific and Cultural Organization (UNESCO) and an experimental ecology reserve by the U.S. Forest Service. Research focuses on the impacts of both climate changes and changes such as increasing atmospheric nitrogen deposition on alpine/subalpine ecosystems. INSTAAR and USGS researchers have cooperated on a variety of projects including those described below.

CWEST Participants: Katie Suding (lead investigator), David Clow, Mark Williams, Noah Molotch

Niwot Ridge LTER Website

Collaborative Research: Earlier snowmelt and streamflow trends being observed

Mark Williams Snow SurveyNiwot Ridge LTER lead investigator and INSTAAR researcher Mark Williams participates in the annual Niwot Ridge snow survey. Conducted in May, the survey tries to capture maximum snow depth across the study area as well as characterize snow quality. Using snow in addition to streamflow data from the Niwot LTER site as well as other sites, USGS researcher, David Clow has found that Colorado snowmelt and streamflow are occurring an average two to three weeks earlier now than in the late 1970s and that these changes are associated with decreasing snowfall and warming springtime air temperatures. If such changes persist, they could have a variety of implications, for example for reservoir operations and for the length of the fire season.


Clow, D. W. (2010). Changes in the timing of snowmelt and streamflow in Colorado: a response to recent warming. Journal of Climate23(9), 2293-2306.  DOI: 10.1175/2009JCLI2951.1

Collaborative research: Impacts of Atmospheric Nitrogen Deposition in the Southern Rocky Mountains

Nitrogen cycles through our planet’s air, water, and soils, and increasingly, this cycle is being affected by human influences.  The rate of atmospheric nitrogen deposition since the start of the 20th century, for instance, has been on the rise. The application of nitrogen fertilizers can contribute to ammonia emissions.  Cars and other vehicles release nitrogen oxides into the air as a result of fossil fuel combustion, and a range of human activities can contribute to particulate nitrogen emissions.  In order to assess the impacts of atmospheric nitrogen deposition in the southern Rocky Mountains, USGS researcher Douglas Burns, examined data from 1) the USGS’s Water Energy and Biogeochemical Budgets (WEBB) field site at LochVale in Rocky Mountain National Park, 2) the Niwot Ridge LTER site, 3) the Glacier Lakes Ecosystem Experiments site in southeastern Wyoming, and 4) the Frasier Experimental Forest just west of the continental divide.  He found that since the mid-20th century, rates of nitrate leaching and nitrate concentrations in surface waters appeared to be increasing in response to increasing rates of atmospheric nitrogen deposition.  However, impacts on ecosystems were not clearly distinguishable from natural variability.  This could potentially change though as human influences on atmospheric nitrogen deposition continue.  Collaboration between the USGS, the Niwot Ridge LTER, and institutions hosting other ecological observatories will play an important role in assessing environmental changes occurring at a regional scale.


Burns, D. A. (2004). The effects of atmospheric nitrogen deposition in the Rocky Mountains of Colorado and southern Wyoming, USA—a critical review. Environmental Pollution127(2), 257-269. DOI: 10.1016/S0269-7491(03)00264-1