Studying local mountains to understand our global future

At the Niwot Ridge Long-term Ecological Research Program (NWT LTER), we study the air, snow, water, soil, microbes, lakes, trees, flowers, and animals in the high mountains of the Colorado Rockies. We measure, experiment and model how all these pieces fit together and have affected the health of our mountains over the last 40 years. Our mission is to better understand how our complex mountain systems are changing and better predict the future of the many critical services these systems provide to all of us living downhill — in Boulder, in Colorado, and beyond.


Niwot Ridge is 1 of 28 US Long Term Ecological Research (LTER) Network sites, funded by the National Science Foundation.



Upcoming events

Project highlights


Tracing land-air exchange of carbon

Air samples taken since the 1960s on Niwot Ridge — the longest record in the continental US — show steadily increases in CO2. While most land areas act as a carbon sink, with plant growth taking in CO2 from the atmosphere, our measures of exchanges of carbon dioxide, water vapor, and energy show that the tundra is acting as a carbon source, putting carbon into the atmosphere. Why? CO2 release in the winter, with microbes are metabolizing old carbon, outweighs the plant uptake. We suspect some of the old carbon being released is from thawing permafrost!

pika in the snow

Signs of stress in the
American Pika

We use pika, an adorable, rabbit-like mammal, to track the health of Niwot Ridge. Pika need cold temperatures to survive, and their decreasing numbers are a troubling sign that the mountains’ health is declining too. We gather information on snow and subsurface temperatures, as well as pika population numbers and their stress hormones, to understand just what pika are telling us about our mountains. The pikas on Niwot Ridge have a small tag on their ear so we can follow how each one is doing, even one named Grumpy, an old timer on the ridge.


A birds-eye view of snow melt

Snow is melting out earlier and our high-mountain summer is getting longer. But did you know that there are some places where snow blows away and other places where snow builds up to form meter deep drifts? We fly drones to follow how all this variation in snow impacts the supply and movement of melt water to vegetation and streams. We use special cameras that indicate temperature as well as vegetation activity, providing an unprecedented high resolution snapshot of dynamic ecohydrologic processes and the snowmelt changes occurring in the Colorado Rockies.


Canary in the coal mine

For more that 35 years we have tracked changes in the 20-acre Arikaree Glacier and in a chain of high-elevation lakes throughout the Green Lakes Valley. We find the the Arikaree Glacier has been thinning by about 1 meter per year for the last 15 years, and that it could disappear in 20 years if current climate trends continue. Our lakes are also staying frozen for shorter and shorter periods each year. Our temperature measures — since the 1950s — suggest that these changes way up near the Continental Divide may be some early warming signs associated with summer and fall warming.


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Niwot at a glance


Within Niwot, you’ll find all of the alpine and montane ecosystems available in the southern Rocky Mountains, including alpine tundra, subalpine coniferous forests, cirque glaciers and glacial landforms, lakes and moraines, cirques, talus slopes, patterned ground, and permafrost.

Home-base collaborators

The Niwot Ridge LTER is part of the Institute of Arctic and Alpine Research and is based at the University of Colorado at Boulder.

History of the Site

Research began at Niwot in the 1940s with the arrival of John Marr, a plant ecologist and World War II veteran, with extensive experience working in cold-weather regions. Thanks to ecological pioneers such as John Marr, Dwight Billings, Hal Mooney, and Bettie Willard, we can trace our understanding of the alpine tundra ecosystem back decades. We maintain the longest continuous record of atmospheric conditions in the continental US and the highest elevation climate station in the US. Niwot Ridge is one of the original six NSF-funded long-term ecological research sites, and the only LTER site in Colorado.



Height of the Arikaree Glacier (12,460 feet!)



Percent of the City of Boulder’s water comes from the Green Lakes Valley



Year the Niwot Ridge LTER was established



Percent of precipitation at NWT that falls as snow