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CARBOMONT Résumé de rapport

Project ID: EVK2-CT-2001-00125
Financé au titre de: FP5-EESD
Pays: Austria

Net ecosystem CO2 exchange of mountain grassland ecosystems

The time-rate-of-change of the atmospheric CO2 concentration depends inter alia on the net exchange of CO2 between terrestrial ecosystems and the atmosphere. If terrestrial ecosystems are a net source of CO2 atmospheric CO2 concentrations are likely to rise and vice versa. CARBOMONT delivers the first data on the net ecosystem CO2 exchange (NEE) of non-forest mountain ecosystems, which up to now are missing in the European carbon inventory.

In the future this data will allow to better assessing the status quo and potential effects of land-use changes on the source/sink relationships of non-forest mountain ecosystems with reference to the Kyoto-protocol.

The investigated mountain grassland ecosystems may be separated into two groups:
- The NEE of managed ecosystems (meadows and pastures) shows to be highly sensitive to the timing and duration of management practises, such as mowing, grazing and fertiliser application. The NEE of these ecosystems ranges from appreciable sinks to large sources of CO2. On average the investigated managed mountain grassland ecosystems absorb 48+/-136 g C m-2 y-1. Soil water availability is a critical factor for the NEE, not only at the sites influenced by the Mediterranean and Continental climates, but as well in the Alps, resulting in larger carbon losses during dry years. Given the balanced carbon cycle of mountain grasslands the ratio of carbon imports (manure) to exports (hay) critically determines whether these ecosystems act as sinks or sources of carbon in terms of their net biome production.
- The NEE of natural, unmanaged ecosystems, which are exclusively associated with high latitudes within the CARBOMONT project, is driven mainly by environmental forcing variables, in particular temperature. These ecosystems act as small sinks for CO2 absorbing on average 20+/-32g Cm-2 y-1.

More information on the CARBOMONT project can be found at:


Alexander CERNUSCA, (Head of Department)
Tél.: +43-512-5075922
Fax: +43-512-5072975