NWT Locations / Saddle...

Research Locations: Saddle

Ownership: USFS - UNESCO Biosphere Reserve
Found within (2nd Order): Niwot Ridge (USFS - UNESCO Biosphere Reserve)

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Saddle Saddle site

Site Information:

  • Mean Elevation: 3500m


The Niwot Ridge saddle is located 5.6 km from the Continental Divide. The area is located along a ridge-top, but in a shallow saddle between the east and west knolls. There is a 10,000 ft2 tundra laboratory on the south side of the saddle, which serves as a staging area for research in all weather conditions. In addition, there is an 80 ft2 subnivean laboratory equipped with snow melt lysimeters that drain into dedicated tipping buckets. These laboratories have year-round motorized access 120-volt line power. There is an Aerometrics wet-chemistry precipitation collector as part of the National Atmospheric Deposition Program (NADP), which has operated continuously since 1984 and is the highest site in the NADP network. The timing, duration, and amount of snow cover has been manipulated since 1994 with a 2.6 x 60 m snowfence, providing a proxy for climate change. There are several meteorological stations at the Saddle site. Climate data exist from 1981 to the present and include temperature, relative humidity, solar radiation, barometric pressure, wind speed, wind direction, precipitation, soil moisture, and soil temperature. NOAA measures surface ozone as well.

Research and Setting:

Soils are Cryochrepts and are approximately 2.0 m in depth over granitic parent material. Soil C in the top 100 mm of soil ranges from 130 to 200 g/kg and soil N pools range from 9 to 15 g/kg [Burns, 1980].

The Saddle is a major research area on Niwot Ridge. Its western half is a snow accumulation area (up to 10 m in some years); its eastern half remains free of snow for most of the winter. Thus, the Saddle contains several quite different vegetation communities within a fairly small area. During the early 1970s, Pat Webber and Diane Ebert-May used ordination techniques to broadly define six vegetation communities, or noda, in the Saddle: fellfield, dry meadow, moist meadow, shrub tundra, wet meadow, and snowbed. Fellfield contains low-statured cushion plants, such as <i>Silene acaulis</i>, and mat-forming plants, such as <i>Trifolium dasyphyllum</i>. Dry meadow is characterized by high cover of the sedge <i>Kobresia myosuroides</i>. Moist meadow is dominated by the forb <i>Geum rossii</i> and the grass <i>Deschampsia cespitosa</i>. Shrub tundra contains high willow (<i>Salix planifolia/Salix glauca</i>) cover. Wet meadow is characterized by abundant <i>Carex scopulorum</i>, a sedge, and <i>Caltha leptosepala</i>, a forb. Snowbed is dominated either by the forb <i>Sibbaldia procumbens</i> or the sedge <i>Carex pyrenaica</i>. Belowground allocation and processes may be particularly important in alpine vegetation, as evidenced by high root:shoot ratios in alpine plant species.

Associated Groups: The Arapaho and Roosevelt National Forests and Pawnee National Grassland,

Measurement and observation location(s) in Saddle:
Saddle, Saddle site, Saddle chart recorder, Saddle data loggers (CR23X and CR1000), Saddle grid, Saddle grid plots, Saddle nodal plots, Saddle snowfence, Saddle stream (007), Saddle wells, Saddle NADP, Subnivean lab, Subnivean data logger, East knoll, West knoll, Tundralab

View 3rd order NWT Saddle in a larger map

Atmospheric science
Microbial ecology
Plant/vegetation ecology
Soil science

CU Boulder

This material is based upon work supported by the National Science Foundation under Cooperative Agreement #DEB-1637686. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necesarily reflect the views of the National Science Foundation.

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