Viera Straskrabova

Biology Centre, Academy of Sciences of Czech Republic

Institute of Hydrobiology, Ceske Budejovice

Biodiversity in aquatic systems –

what are the important drivers and pressures?

ALTERnet Summer School,Peyresc, 2007

•Types of aquatic systems, their main characteristics compared toterrestrial ones

•Main groups of aquatic organisms (functional and taxonomic) in freshwater aquatic systems

•The most important threats to biodiversity in aquatic systems, their causes, consequences and interrelations: eutrophication, acidification, toxic pollutants, land use changes, climate change, overexploitation, alien and invasive species.

•Pressures and drivers act: directly = upon the aquatic systems, indirectly = upon the catchment.

•The most important services and goods of aquatic ecosystems and their deterioration by pressures and drivers (and by biodiversity loss and/or change): water quality and quantity (water as a resource), fish production (aquaculture).

•Framework Water Directive

TYPES OF AQUATIC SYSTEMS

LAKESRIVERS

TERRESTRIAL

WETLANDS

RESERVOIR

natural succession man-made

Lake Bajkal

Mountain lakes

Reservoir

Main differences from terrestrial systems

PRIMARY PRODUCERS small, fast growing, less visible

HETEROGENEITY smaller

HERBIVORES consume whole organisms

OXYGEN often less available

LIGHT often limiting

WATER everywhere round

Selenga

•Production processes, energy budget, turnover of nutrients and organic matter in relation to surrounding ecosystems (terrestrial ones, catchment).

Aquatic systems mostly are NET HETEROTROPHIC

Respiration surpasses production

This means energy input from terrestrial systems

Especially rivers have higher allochthonous input than own production

Input of nutrients, and organicsfrom terrestrial system

River and reservoir in the catchment

Connected with ground water

Lacustrine

Riverine

Spatial structure of aquatic ecosystems

Interphases - Ecotones

WATER (pelagic) --------------------------- (benthic) SEDIMENT

WATER ------------------------- BIOTA ------------------ SEDIMENT

AQUATIC ---------------------(littoral)--------------- TERRESTRIAL

Hot spots of biodiversity, nutrient cycling, chemical and biochemical processes

Main groups of aquatic organisms

Functional groups

Plankton, benthos, (nekton, neuston), periphyton

Large taxonomic groups

Bacteria, cyanobacteria (blue-greens), algae, protozoans, rotifers, crustaceans, fish;

Vascular plants, mosses, snails, worms, insects and/or their larvae

Aquatic vertebrates other than fish, semi-aquatic

Biodiversity problems

Species extinction – loss of species

Replacement by other species

Change of food chain

Change or deterioration of habitat

They act directly on the aquatic system

and/or

indirectly on the cachment, surroundings etc.

They can directly effect species loss

and/or

Indirectly efect the species through changes

of conditions in habitats

Important pressures and drivers on aquatic BD

Direct effect on species -

human induced

Overexploitation – fishing

Introduction of new species

Invasion (human induced) of alien species

Habitat change for aquaculture, artificial

(semi-natural) aquatic systems

Pressures and drivers effecting conditions in aquatic systems (habitat change or loss)

Usually caused by the input from catchment or from the air

Eutrophication – increase of nutrientsincreased biomass, change of species, oxygen depletion

Acidification – S and N oxides from the air

Toxic wastes – industrial wastes, air pollution

Climate effect – warming, change of water quantity

Land use changes – in catchment, complex, diverse effects

Land use changes, interconnected with the others

Deterioration or loss of habitats, fragmentation, loss of connectideness (in rivers)

Changes in water quantity – surface level decrease or increase: desertification, flooding

Changing conditions – changed input of nutrients and/or toxic wastes

HUMAN INDUCED and CLIMATE CHANGE

Goods and services of aquatic ecosystems, human demands

Water cycle in landscape – transport – connection with other ecosystems

With ground water – soil – aquifers

With the air – humidity – transport

WATER QUANTITY flood control, water storage, irrigation (change of habitats - dams, overexploitation, climate effect)

WATER FOR TRANSPORT and ENERGY navigation, hydropower generation (pollution, change of habitats - dams)

WATER FOR DIRECT HUMAN USE Drinking water source – demand for low productive system with low biomass composed of „desirable organisms“

WATER FOR PRODUCTION OF „FOOD“ Fish production – demand for medium productive system

Swimming, sport fishing, “natural beauty”

MULTIPLE USES CONFLICTING USES

DIRECTIVE 2000/60/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL

of 23 October 2000

establishing a framework for Community action in the field of water policy

Coordinate Member States' efforts to improve the protection of Community waters in terms of quantity and quality, to promote sustainable water use, to contribute to the control of transboundary water problems, to protect aquatic ecosystems, and terrestrial ecosystems and wetlands directly depending on them, and to safeguard and develop the potential uses of Community waters.

Characteristics of the river basin district, review of the environmental impact of human activity and economic analysis of water use

Monitoring of surface water status, groundwater status and protected areas

for surface waters such programmes shall cover:

(i) the volume and level or rate of flow (water quantity) to the extent relevant for ecological and chemical status and ecological potential, and

(ii) the ecological and chemical status and ecological potential – water quality

Groups of aquatic organisms recommended to be monitored:

• Phytoplankton species, abundance

• Macrophytes – species, abundance

• Benthic invertebrates

• Fish