A sensitive ecosystem
- What's life like above treeline?
The ecosystem visible from the TundraCam is alpine tundra, attuned to the harsh winters, dry conditions, and short growing season of the high-mountain climate. Climatic factors are extreme and require plants and animals to adapt to snow cover, high winds, and strong variations in weather from year to year. The western half of the Saddle site visible from the camera collects up to 10 meters (33 feet) of snow in some winters, while the eastern half is usually snow-free. The differences in precipitation and slope foster half a dozen very different plant communities in a fairly small area: fellfield, dry meadow, moist meadow, shrub tundra, wet meadow, and snowbed. Soils are Cryochrepts, a gravelly loam with a thin top layer of partially decomposed tundra litter, over granitic parent material.
Long-lived perennials dominate tundra plant communities. They can live for centuries - a few as long as 400 years. Plants are low to the ground to withstand the strong winds that sweep across the tundra. Many are cushion plants, which grow together in clumps that help protect them from cold. Most of their biomass is concentrated in the roots, safely below ground. Bees are scarce at high elevations and some plants reproduce by division rather than relying on flower pollination. Other plants can wait for years to seed. Still others seed incredibly quickly: the snow buttercup (Ranunculus adoneus) flowers through inches of snow and takes only a month to pass from its first appearance to seed production.
- More Plants
Alpine plants found on Niwot Ridge include western yellow paintbrush (Castilleja occidentalis), alpine forget-me-not (Eritrichum aretioides), alpine sunflower or Old Man of the Mountain (Hymenoxis grandiflora), and Arctic sandwort (Minuartia obtusiloba). Many alpine plants have complex relationships with wildlife. Alpine avens (Acomastylis rossii), a low-growing wildflower, secretes bitter tannins and other compounds that act as preservatives. Pikas collect “haypiles” of alpine avens leaves, along with other plants, to store as winter food. The compounds keep the haypiles from molding, and the tannins, which break down over time, may help protect the haypiles from other herbivores before the winter comes.
Only one bird, the white-tailed ptarmigan, lives on the tundra year-round. Summer visitors include water pipits, rosy finches, horned larks, and white-crowned sparrows. Small mammals, such as yellow-bellied marmots, golden-mantled ground squirrels, deer mice, voles, and pikas make their homes on the tundra. A few transient mammals visit the tundra as well, including snowshoe hares, porcupines, badgers, and weasels. Elk are the only large mammals at the Niwot Ridge site.
- Life on the edge
- Tundra Lab
Scientists are studying the links between the tundra ecosystem, climate, and the region's complex terrain. Changes in climate and atmospheric deposition of nitrogen to these habitats are causing rapid changes in some portions of the system but not in others. Among other topics, researchers are looking at dissolved organic matter in alpine streams, the chemistry of alpine plants, loss of biodiversity from nitrogen fertilization, carbon cycling, interactions between animals and plants, and microbes in the soils.
TundraCam is sponsored by the University of Colorado at Boulder's: