The newly established Bonanza Creek LTER site in Fairbanks, Alaska, will examine successional changes in controls over ecosystem function in upland and floodplain taiga forests. The central hypothesis of the program is that the pattern of succession is determined primarily by initial site characteristics and by the life history traits of component species and that the rate of successional change is then determined by vegetation-caused changes in environment arid ecosystem function.
The major emphases in this program include:
- Demographic and physiological controls over vegetation change (LA. Viereck and F.S. Chapin)
- Vegetation-caused changes in resources and standing crops of biomass and nutrients (K. Van Cleve, C.T. Dyrness, and J. Yarie)
- Controls over microbial activity and nutrient supply (P.W. Flanagan, K. Van Cleve, P.B. Reichardt, and R.G. Gates)
- The role of herbivores as consumers and modifiers of succession (J.P. Bryant)
Major study sites are three replicate stands in early, mid, and late succession in upland south-facing slopes and in the floodplain of the Tanana River.
Several long-term experiments are planned that will serve as a faculty for taiga and visiting researchers.
- Resource availability will be altered by adding nitrogen, sawdust, or sucrose or by limiting precipitation input
- The natural pattern of colonization and succession will be altered by planting artificial communities in early succession (vegetation-free silt, N-fixing alder, spruce, or alder + spruce)
- Moss will be removed to document the role of mosses in controlling soil temperature and nutrient cycling
- Herbivores will be excluded from some of the artificial communities
Measurements planned for these experiments include plant establishment and growth, sod nutrient availability, biomass and standing stocks of nutrients, sod microbial and invertebrate activity, and secondary metabolite concentrations in plants arid forest floor.
Some of the major emphases in the taiga LTER program are on
- Combining population and ecosystem approaches to the study of succession
- Considering in detail the controls over nutrient availability as mediated by microbial processes
- Exploring the role of plant-derived secondary metabolites in regulating nutrient cycling
- Examining the role of mammalian herbivores in causing successional change
The taiga LTER group encourages participation from other researchers, particularly those working at other LTER sites. We particularly wish to encourage research on root production and turnover, insect herbivory, and secondary productivity.
For information about the Taiga LTER site contact Dr. Keith Van Cleve, Agricultural and Forestry Experiment Station, University of Alaska, Fairbanks, 99775.