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