De Luca, Tom
- Department of Forest Vegetation Ecology, Swedish University of Agricultural Sciences
Research article2004Peer reviewed
Zackrisson O, DeLuca TH, Nilsson MC, Sellstedt A, Berglund LM
There is little understanding of successional dynamics of N fixation in northern boreal forests. Recent evidence suggests that N fixation by cyanobacteria in association with the common feather moss Pleurozium schreberi contributes to a significant proportion of the total N economy. The Purpose Of the work herein was to determine how time since last fire influences N fixation rates in boreal forests. We evaluated seasonal N fixation rates oil a total of 12 natural forest preserves varying in time since last fire (35-355 years). Each site was monitored for N fixation activity using a calibrated acetylene reduction assay. Nitrogen fixation rates were found to increase linearly with time since fire. This increase in N fixation with succession is likely a function of degree of colonization by cyanobacteria and site factors Such as presence of available N. Surface applications of 4.5 kg N(.)ha (1.)yr(-1) as NH4NO3 Were found to eliminate N fixation while applications of P resulted in only a slight and temporary increase of N fixation rates. In contrast to common observation our findings suggest that N fixation in boreal forests becomes more important in late Succession. Limited N availability in late Succession is clearly one of the primary drivers of N fixation rates in boreal forest ecosystems. These findings may help to explain the origin of high rates of net N accumulation in Soil unaccounted for at northern boreal sites
Ecology
2004, Volume: 85, number: 12, pages: 3327-3334
Publisher: ECOLOGICAL SOC AMER
Forest Science
DOI: https://doi.org/10.1890/04-0461
https://res.slu.se/id/publ/4876