News From The Sites: Niwot Ridge LTER Program

Network News Spring 1987, Vol. 1 No. 1
Site News

A growing concern over whether or not mid-latitude, U.S. alpine regions will be susceptible to damage from acid deposition caused the U.S. Forest Service arid other regional scientists to turn to the University of Colorado LTER program (CULTER) for help. The current hypothesis suggests that extant levels of acid deposition in the sensitive Colorado mountains will lead to soil acidification and adverse affects to the biota of the alpine within decades. The CULTER understanding of soil-water process chemistry, water and soils databases, and results from our long-term low-level, simulated acid rain experiments are in great demand by regional scientists. While common sense suggests acidification is likely, especially when the present acid deposition loading rates and the prevalence of granitic/gneissic parent rocks are considered, we now have good reasons to seriously doubt the conventional prediction of inevitable acidification.

During the summer of 1986 a new series of long- term experimental plots designed to link the Ridge and Valley continuation experiments (from LTER-l) were established. These manipulation plots, known as the Martinelli Slope Plots, are physically tied to the long-term and continuing micro-watershed studies of Dr. Nelson Caine. Monitoring of soil-water chemistry for nutrient flux will test our theories on the resistance and resilience of alpine communities to disturbance. Disturbances include a major anthropogenic impact, trampling, and a major natural impact -- gopher invasion. Complete denudation by cryogenic freezing as a control will separate the effects of vegetation removal from trampling compaction effects.

Important new long-term, climatic databases were discovered in 1986. The first, a climate record dating from 1910 at Silver Lake (3,115 m), a site near our current study areas, was uncovered in the U.S. Weather Bureau archives. This discovery resulted, in part, from Dr. Thomas Karl’s attendance at the January 1986 Database Meeting at Jornada and his efforts following the meeting. The second discovery was a Soil Conservation Service database going back to 1938 for a snow course near our study area.

Dr. Donald (Skip) Walker, Institute of Arctic and Alpine Research Plant Laboratory has joined the CULTER team. Skip’s expertise is in geographic information systems and landscape mapping and modeling, especially of Arctic regions.

“A Hierarchical Conceptual Model of the Alpine Geosystem” (French, N.R., Arctic and Alpine Research 18:133-149) presents CULTER’s efforts to conceptualize the immense complexities of the alpine geosystem. The hierarchical model links spatial levels from the space required by a single organism to 100s of kilometers, the size of a watershed, and temporal scales from diurnal to 10,000s of years. Climate and hydrology plus geochemical processes are seen as driving variables linking all levels of the hierarchy. Modifications of this model would be applicable at all sites and reprints are available on request.