Simulated nitrogen deposition affects wood decomposition by cord-forming fungi
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Anthropogenic nitrogen (N) deposition affects many natural processes, including forest litter decomposition. Saprotrophic fungi are the only organisms capable of completely decomposing lignocellulosic (woody) litter in temperate ecosystems, and therefore the responses of fungi to N deposition are critical in understanding the effects of global change on the forest carbon cycle. Plant litter decomposition under elevated N has been intensively studied, with varying results. The complexity of forest floor biota and variability in litter quality have obscured N-elevation effects on decomposers. Field experiments often utilize standardized substrates and N-levels, but few studies have controlled the decay organisms. Decomposition of beech (Fagus sylvatica) blocks inoculated with two cord-forming basidiomycete fungi, Hypholoma fasciculare and Phanerochaete velutina, was compared experimentally under realistic levels of simulated N deposition at Wytham Wood, Oxfordshire, UK. Mass loss was greater with P. velutina than with H. fasciculare, and with N treatment than in the control. Decomposition was accompanied by growth of the fungal mycelium and increasing N concentration in the remaining wood. We attribute the N effect on wood decay to the response of cord-forming wood decay fungi to N availability. Previous studies demonstrated the capacity of these fungi to scavenge and import N to decaying wood via a translocating network of mycelium. This study shows that small increases in N availability can increase wood decomposition by these organisms. Dead wood is an important carbon store and habitat. The responses of wood decomposers to anthropogenic N deposition should be considered in models of forest carbon dynamics.
KeywordsBasidiomycete fungi Carbon cycle Forest litter decomposition Wood decay Nitrogen cycle
The authors thank Mike Morecroft, Michele Taylor, George Tordoff, and Juliet Hynes. The study was funded by NERC grant NER/A/S/2002/882.
- Bréda N, Huc R, Granier A, Dreyer E (2006) Temperate forest trees and stands under severe drought: a review of ecophysiological responses, adaptation processes and long-term consequences. Ann For Sci 63:625–644Google Scholar
- Eriksson K-E, Blanchette RA, Ander P (1990) Microbial and enzymatic degradation of wood and wood components. Springer, New YorkGoogle Scholar
- Findlay WPK (1934) Studies in the physiology of wood-destroying fungi. I. The effect of nitrogen content upon the rate of decay of timber. Ann Bot 48:109–117Google Scholar
- Grove S, Meggs J (2003) Coarse woody debris biodiversity and management: a review with particular reference to Tasmanian wet eucalypt forests. Aust For 66:258–272Google Scholar
- Jonsson BG, Kruys N, Ranius T (2005) Ecology of species living on dead wood—lessons for dead wood management. Silva Fenn 39:289–309Google Scholar
- Langham SJ (1999) The impact of nitrogen deposition on natural and semi-natural ecosystems. Kluwer, DordrechtGoogle Scholar
- Rayner ADM, Boddy L (1988) Fungal decomposition of wood: its biology and ecology. Wiley, ChichesterGoogle Scholar
- Rodwell JS (1991) British plant communities volume 1—woodlands and scrub. Cambridge University Press, CambridgeGoogle Scholar
- Swift MJ, Heal OW, Anderson JM (1979) Decomposition in terrestrial ecosystems. Blackwell, OxfordGoogle Scholar