Download Biodiversity in aquatic systems - Potsdam Institute for Climate Impact

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 to
terrestrial 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
RIVERS
LAKES
RESERVOIR
natural succession
man-made
WETLANDS
TERRESTRIAL
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
River and reservoir in the catchment
Input of nutrients, and organics
from terrestrial system
Connected with
ground water
Riverine
Lacustrine
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
Important pressures and drivers on aquatic
BD
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
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 nutrients
increased 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