Temporal and Spatial Variability of Peat Accumulation and Vegetation of Post-Fire Boreal BogsEPA Grant Number: FP916340
Title: Temporal and Spatial Variability of Peat Accumulation and Vegetation of Post-Fire Boreal Bogs
Investigators: Benscoter, Brian W.
Institution: Southern Illinois University - Carbondale
EPA Project Officer: Graham, Karen
Project Period: January 1, 2004 through December 31, 2006
Project Amount: $107,381
RFA: STAR Graduate Fellowships (2004) RFA Text | Recipients Lists
Research Category: Fellowship - Terrestrial Ecology and Ecosystems , Academic Fellowships , Ecological Indicators/Assessment/Restoration
The objective of this research project is to assess the temporal and spatial variability in –post-fire peat accumulation to develop functional post-fire recovery trajectories. Peatland ecosystems cover an estimated 3-4 percent of the Earth’s land surface, with 100.8 x 106 ha distributed in the boreal and subarctic regions of Canada. Photosynthetic production exceeds microbial decomposition in these ecosystems, resulting in an accumulation of organic matter. Worldwide, boreal, and subarctic peatlands sequester atmospheric carbon at a rate of 76 Tg yr-1 representing a 455 Pg carbon pool, with continental western Canadian peatlands retaining 42 Pg C as peat, collectively. Within and between individual landforms, peatland function varies substantially as a result of variation in vegetation composition and edaphic conditions. Bog peatlands vary microtopographically, particularly with respect to vegetation dominance and surface height above water table, resulting in functional differences. Fire severely compromises peatland functional capacity, consuming approximately 1,470 km2 of peatland annually in western Canada, directly releasing 3.1 Tg C through combustion. The indirect effects of fire, however, may be even more pronounced. Combustion removes surface vegetation, resetting the successional process and stopping photosynthetic production as well as possibly increasing decomposition rates, resulting in the net release of carbon for many years post-fire.
I will determine vegetation successional pathways, rates of production and decomposition, and their combined affect on bog peat accumulation by comparing these processes along a chronosequence of historically burned bog peatlands in Alberta, Canada, to develop functional post-fire recovery trajectories. Thirteen sites with various fire recovery times (1-140 years) were chosen using maps of peatland distribution and historical fire occurrence for Alberta. Vegetation composition will be determined spatially, by conducting vegetation surveys, and temporally through macrofossil analysis of peat soil cores to determine the successional patterns of each site. Reestablishment of moss on burned peat will be experimentally induced by seeding with combinations of moss species fragments and compared to control treatments to determine the importance of competition and the mechanisms of reestablishment. Production will be measured using the cranked wire method for the moss layer and litter traps for vascular input to the soil carbon pool. Peat cores sectioned at 3-cm intervals and placed into decomposition bags will be used to determine post-fire decomposition rates temporally and as a function of depth. All studies will be referenced to distance from the water table for functional comparisons. The results of all studies will be integrated to determine the temporal trajectory of peatland recovery, both physically and functionally. Preliminary conceptual modeling suggests an 8-year lag post-fire before positive peat accumulation returns, with an even greater time period (> 20 years) before the peat carbon pool returns to its prefire magnitude.