3.9. Straskrabova

Keynote Presentations from the 2nd ALTER-Net Summer School, Peyresq 1 - 13 September 2007

Speaker: Viera Straskrabova
verastr -at- hbu.cas.cz
Biology Centre, Academy of Sciences of Czech Republic, Institute of Hydrobiology, Na sadkach 7, Ceske Budejovice CZ37005, Czech Republic

Title of the talk: Biodiversity in aquatic systems - what are the important drivers and pressures? (pdf: 4MB)

Summary of the talk by Karin Didderen and summary by Jasmin Godbold (pdf)

Biodiversity in aquatic systems - what are the important drivers and pressures?

Types of aquatic systems (freshwater!), their main characteristics compared to terrestrial ones.
Main organismal groups (functional, taxonomic) in freshwater aquatic systems.
The most important threats to BD in aquatic systems, their causes, consequences and interrelations: eutrophication, acidification, toxic substances, land-use changes, climate change, human overexploitation of resources, alien and invasive species. Pressures and drivers: direct = upon the aquatic system, indirect = upon the catchment.
The most important services and goods of aquatic systems and their deterioration by BD loss:
(i) good water quality for human use (water itself as a resource), which needs low-productive aquatic systems with low biomass, but complete pelagic food webs, and
(ii) high fish production (water as productive ecosystem), which needs aquatic systems with higher to moderate biomass and/or production and with diversity of habitats.
These are two different and conflicting demands for a desirable status of aquatic systems.
Some drivers and pressures might effect also water quantity – like land-use changes, climatic events – floods, drought, overexploitation of water for direct use (irrigation, drinking water, industrial demand), which in consequences also changes the quality.
European Framework Water Directive