Decomposition processes interacting with microtopography maintain ecosystem heterogeneity in a subalpine grassland
- 62 Downloads
Grasslands are among the largest ecosystems in the world and store up to 30% of the global reserves of carbon. Decomposition processes have a crucial role in maintaining carbon balance, but few studies have investigated the heterogeneity of this process at small scale, especially in alpine ecosystems. We aimed at investigating the interactions between decomposition and environmental heterogeneity at microscale (i.e. elevation gradient <1 m) in a subalpine grassland on the western Italian Alps characterised by the presence of parallel hummock and hollow areas.
In the study area we monitored microenvironmental drivers (soil temperature and soil water content), plant distribution and decomposition. The latter was studied through a litter bags approach followed by elemental analysis, 13C NMR and FT-IR spectroscopies.
Microtopography exerted a direct and indirect control over litter decomposition by affecting plant species distribution and microclimatic conditions. The different elemental and biochemical properties of plants, interacting with microtopography, led to a higher decomposition rate of forb than grass litter, and in hollow than in hummock areas. The observed differences were both quanti- and qualitative.
Decomposition processes bridge the gap between plant community structure and ecosystem functioning, determining a feedback mechanism that maintains ecosystem heterogeneity at the microscale.
KeywordsForbs and grasses FT-IR Litter bags Litter chemistry Nardus stricta NMR
A special thanks to Valentina Mello, Roberta Negri and Guido Teppa for their help during field work, to Marco Prati for his kind support in the lab, and to Compagnia San Paolo for funding my PhD project.
- Berg B, McClaugherty C (2014) Plant litter. Decomposition, humus formation, carbon sequestration, Third edn. Springer-Verlag, BerlinGoogle Scholar
- Bradshaw AD, Lodge RW, Jowett D, Chadwick MJ (1964) Experimental investigations into the mineral nutrition of several grass species: IV. Nitrogen Level J Ecol 52:665–676Google Scholar
- Bryant DM, Holland EA, Seastedt TR, Walker MD (1998) Analysis of decomposition in alpine tundra. Can J Bot 76:1295–1304Google Scholar
- de Coulon J (1923) Nardus stricta. Étude physiologique, anatomique, et embryologique. Mem Soc vaud Sci nat 6:245–332Google Scholar
- Epstein HE, Burke IC, Lauenroth WK (2002) Regional Patterns of Decomposition and Primary Production Rates in the U.S. Great Plains. Ecology 83:320–327.Google Scholar
- Gerola FM, Gerola DU (1951-1954) Ricerche sui pascoli delle Alpi centro-orientali. Le praterie dell’Altipiano di Asiago, Museo Storia Naturale Venezia TridentinaGoogle Scholar
- Leith H (1978) Pattern of primary productivity in the biosphere. Hutchinson & Ross, StroudsbergGoogle Scholar
- R Development Core Team. R (2005) A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria. http://www.R-project.org
- Seastedt TR, Walker MD, Bryant DM (2001) Controls on decomposition processes in alpine tundra. In: Bowman WD, Seastedt TR (eds) Structure and function of an alpine ecosystem: Niwot ridge. Colorado. Oxford University Press, New York, pp 222–236Google Scholar
- Sharp RP (1942) Soil structures in the St. Elias range, Yukon territory. Geomorphology 5:274–301Google Scholar
- Socrates G (2004) Infrared and Raman characteristic group frequencies: tables and harts. John Wiley & Sons Ltd., EnglandGoogle Scholar
- Suttie JM, Reynolds SG, Batello C (2005) Grasslands of the world. FAO, Plant production and protection series, No. 34Google Scholar
- Swift MJ, Heal OW, Anderson JM (1979) Decomposition in terrestrial ecosystems. University of California Press, BerkeleyGoogle Scholar
- Tutin TG, Heywood VH, Burges NA, Moore DM, Valentine DH, Walters SM, Webb DA (1964–1980) Flora Europea. Cambridge University Press, CambridgeGoogle Scholar