global change impact on ecosystems reinhart ceulemans and ivan nijs university of antwerp,...
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Global change impact on ecosystems
Reinhart Ceulemans
and
Ivan NijsUniversity of Antwerp, Department of Biology
(UA-PLECO)
• Impact on ‘structure, function and distribution of ecosystems’ (productivity, control measures, C sequestration)
• Impact on ‘water and hydrology’ (hydrological basins, flow, sensitive fen ecosystems)
• Impact on ‘biodiversity’ (extinction, control measures)
• Interactions ‘ecosystems - CO2 and other
GHG’ (terrestrial sink, land use, soil acidification)
• ‘What drives ecosystem changes ?’ (one or more factors, social ‘drivers’)
C-stocks in terrestrial ecosystems and soil
(F. Veroustraete, VITO and B. Van Wesemael, UCL)
Stocks Per unit area (ton C / ha)
Totals Belgium (kton C)
Forest biomass 94.4 53,800
Humus in forests 61.5 35,000
Soil, 0-30 cm 58 (10-190) 144,000
Soil, 0-100 cm 98 (18-986) 241,000
Fluxes of C - terrestral ecosystems and soil(F. Veroustraete, VITO and B. Van Wesemael, UCL)
Fluxes Per unit area (ton C / ha / year)
Total Belgium (kton C / year)
NEP all vegetation
4.8 14,600
NEP forest accretion
5.0 2,800
Forest felling 2.1 1,200
Soil via management
? 500-800
Terrestrial ecosystems = carbon sink?
• Net ecosystem-productivity (NEP) Belgium: 14,500 kton C per year (1997) (C-Fix model, VITO)
Total amount of C in soil is much larger than in wood and forests
• Geographical link between carbon stock in the soil and vegetation productivity
• Agricultural zones: low soil carbon
• Source: (Lettens et al., 2004) Van Orshoven & Lettens
Evolution of C-sequestration(L. François, ULg)
• Carbon sequestration will increase under global change conditions, but in function of:
(i) age; (ii) changing weather conditions; (iii) forest management.
Plant and animal species disppear today by approximately 1,000 x the natural speed of extinction
climate change
pollution
overhunting and overfishing
habitat-destruction
biological invasions
landscape fragmentation
eutrophication
Population viability analysis
(E. Le Boulangé, UCL)
1775 1973
Lienne vallei, Lierneux
current situation
Model: predicts population size of vulnerable species under different scenarios of change
+ grazing
+ grazing
+ warmer climate
CARAIB model
(Ulg, L. François)
Agricultural area: 50% grassland
Grassland species adapted to a moderate climate
apr may jun jul aug sep
+
-
Growth response to a warmer
climate
“Change is seldom driven by a single
factor”
(H. Geist, UCL)
CO2 concentration: higher
Air temperature: higher
Climate: more extreme
Biodiversity: lower
Invasive exotics: more
Habitat fragmentation: stronger…
interaction?
Exotic invasive plants
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