ENVIRONMENTAL CHANGE RESEARCH CENTRE
Challenges for management of
freshwater ecosystems in Europe
Martin Kernan
Environmental Change Research Centre,
University College London
The consequences of anthropogenic actions on European
freshwaters are considerable,
increased ultra-violet irradiation;
acidification by sulphur and nitrogen compounds;
mobilisation of organic substances from soils;
accelerated erosion and sedimentation in river channels;
damming and diversion of river flows;
eutrophication by nitrogen and phosphorus compounds;
structural alteration of rivers for flood prevention in the interests of agriculture;
fragmentation of habitats;
discharge of alien substances, many of them toxic; and
introduction of alien species and selective removal of others
Restoration strategies
• Acidification
– Reduction in sulphur deposition (UNECE protocols)
– Liming
– Improved forestry practices
Restoration strategies
• Eutrophication:
– Reduce external load
– Create buffer strips
– Remeandering of streams
River habitat restoration
Re-braiding
Re-meandering
Addition of woody debris
Persistent Organic Pollutants
Annex A (Elimination)
Aldrin
Chlordane
Chlordecone
Dieldrin
Endrin
Heptachlor
Hexabromobiphenyl
Hexabromodiphenyl ether and heptabromodiphenyl ether Hexachlorobenzene (HCB)
Alpha hexachlorocyclohexane
Beta hexachlorocyclohexane
Lindane
Mirex
Pentachlorobenzene
Polychlorinated biphenyls (PCB)
Tetrabromodiphenyl ether and
pentabromodiphenyl ether
Toxaphene
Annex B (Restriction)
DDT
Perfluorooctane sulfonic acid, its salts and perfluorooctane sulfonyl fluoride
Annex C (Unintentional production)
Polychlorinated dibenzo-p-dioxins (PCDD)
Polychlorinated dibenzofurans (PCDF)
Hexachlorobenzene (HCB)
Pentachlorobenzene
Polychlorinated biphenyls (PCB)
Monitoring system for the Water Framework
Directive
Restoration
Biological indicators
Metric 1
Metric 2
Metric 3
Restoration
Composition and abundance
Supporting physico-chemical
parameters
Metric 1
Metric 2
Quality
class
Restoration
Metric 3
Oxygen, salinity, acidification, nutrients
Restoration
Supporting hydromorphological
parameters
Metric 1
Metric 2
Metric 3
Restoration
Hydrological regime, morphological conditions
eutrophication
hydromorphology
acidification
other stressors
WFD & HD increased drive for
restoration and remediation –
‘good ecological status’
Future climate change In Europe
Mean temperature anomaly
for 2071-2100
• hotter everywhere
• west-east and north- south
gradients
HadRM3 - A2a TEMP
Future climate change In Europe
Mean precipitation anomaly,
2071 - 2100
little change in mid-latitudes
• wetter in the north
• drier in the south
HadRM3 A2a PRECIP
Regional predictions are very uncertain, and much
depends on the behaviour of the NAO / AO. Seasonality
and extremes in
temperature and
precipitation regimes
are also predicted to
change. Such changes,
would significantly
affect the hydrology,
chemistry and
ecology of rivers,
lakes and wetlands
and interactions
between these.
Euro-limpacs : Integrated
Project to Evaluate the Impacts
of Global Change on European
Freshwater Ecosystems
Euro-limpacs is funded by the European Union under Thematic
Sub-Priority 1.1.6.3 “Global Change and Ecosystems"
of the 6th Framework Programme
Co-ordinators: Environmental Change Research Centre, UCL
Euro-limpacs aims and project structure
An integrated project to assess:
• how will (European) freshwater
ecosystems respond to future
climate change directly and
indirectly, through interactions
with hydromophology,
eutrophication, acidification and
toxic substances?
• how can European freshwater
systems thereby be better
managed, e.g. with respect to the
EU Water Framework Directive?
Rationale
•Climate changing rapidly beyond the range of recent
(historical) natural variability
•Aquatic ecosystems under stress from land use
change and pollution face additional pressures from
climate change
•Need to understand direct effects of climate change
and also indirect impacts through interaction with
pollutants
Objectives
•to improve understanding of how global change, especially climate
change in its interaction with other drivers (land-use change, nutrient
loading, acid deposition, toxic pollution) has changed, is changing
and will change the structure and functioning of European freshwater
ecosystems (rivers/streams, lakes and marginal wetlands);
•to encapsulate this understanding in the form of predictive, testable
models;
•to identify key taxa, structures or processes (indicators of aquatic
ecosystem health) that clearly indicate impending or realised global
change through their loss, occurrence or behaviour;
Euro-limpacs- Work programme structure
WP1.
Direct Impacts of
Climate Change
WP2.
Climatehydromorphology
interactions
WP3.
Climatenutrient
interactions
WP4.
Climateacidification
interactions
WP5.
Climate-toxic
substances
interactions
WP6.
Integrated
Catchment Modelling
and Analysis
WP7.
Indicators of
ecosystem health
WP8.
Reference
conditions &
restoration
strategies
WP10.
Dissemination &
Training
WP9.
Tools for catchment
management
Direct effects of climate change
Hot Summer 2003
Switzerland
(Schär et al., 2004)
Impact on lake water column
Zürichsee (CH)
Strong increase in
• surface water temperature
• lake stability
• oxygen depletion in hypolimnion
Enhanced risk of deep water anoxia
Number of standard deviations
(Modified from Jankowski et al., 2006)
Ecological thresholds in high mountain lakes
Relation of organism goups and environmental factors
Ice cover duration (days)
Ice cover duration (days)
diatoms, rotifers,
planktonic crustaceans,
chironomids, chydorids
climate, lake size,
trophic state,
water chemistry
240
Duration of ice cover
as ecological threshold
in high mountain lakes
200
~ 190 days
160
120
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Species assemblage
Median, first and third quartiles, total range
of ice cover duration for species assemblages
(Catalan et al., 2010)
GENERALLY….
an increase in the surface water temperature of lakes and streams
across Europe, especially those at high altitudes and latitudes, and
strengthening and lengthening of lake stratification in summer;
an increase in hypolimnetic temperature of large deep lakes, which
tend to cause a reduction in oxygen concentration in bottom waters,
especially in summer;
a reduction in lake ice-cover, including both a later freezing date in
autumn and an earlier spring thaw, that increases the length of the openwater growing season, the duration and intensity of the autumn overturn,
and an increase in deep-water oxygen concentrations;
melting of mountain glaciers and permafrost causing changes to
discharge regimes in mountain streams and release of solutes and
pollutants to surface waters;
(Nickus et al., 2010)
Climate – hydromorphology interactions
Effects of climate change on hydraulic conditions and
channel morphology at the catchment, reach & habitat scale
Effects of restoration measures in European rivers
Effects of climate change on lake sediment accumulation
rate
Currently the magnitude of the effects of climate change on hydromophology of
streams and rivers is small compared with the impact of land-use changes but in
future, particularly in marginal areas in southern and northern Europe and at high
elevations this climatic signal will become more significant. This is likely to have
major impacts on restoration efforts in future.
(Verdonschot et al., 2010)
Climate – hydromorphology interactions
increased and more intense precipitation
more spates and droughts
intensification agriculture
siltation, scouring
deterioration
• morphology
• biodiversity
abandoning agriculture
widening buffer strips
improving
• morphology
• biodiversity
Climate – eutrophication interactions
Mesocosm experiments to study the combined effects of
warming and nutrient enrichment on freshwater ecosystems
Relative cumulative respired C after 49 days
control
fertilized
100,00
90,00
Stream and wetland experiments at paired sites
carbon ( mgC/ mg SOC)
80,00
70,00
60,00
50,00
40,00
30,00
20,00
10,00
0,00
Warm
Ambient
Space for time substitution studies – can analogues provide
us with an insight as to what might happen under future
climate change
Palaeolimnological studies - To employ sediment records to
provide a temporally integrated, longer-term view of within
lake changes than can be provided by monitoring data
Climate – eutrophication interactions
Warming will exacerbate many, though not necessarily all, symptoms of
eutrophication, but there remains considerable uncertainty.
1. Responses are complex and varied depending on the specific context. As a
result, specific measures to be taken in particular situations will be associated
with extreme uncertainty in view of the limited scope of research that is likely to
be achievable over the period in which climate change is occurring.
2. Several lines of evidence hint at biological feedback mechanisms that may result
in increased respiratory production of carbon dioxide, if not of nitrous oxide
(N2O), and methane (CH4). This might mean that the purely physical models that
are the basis for climate change predictions made by the IPCC are severe
underestimates.
3. As world population grows, pressure to grow more food, whilst simultaneously
producing crops for biofuel, will probably lead to further increased nutrient inputs
and an intensification of eutrophication problems in receiving freshwaters.
(Jeppesen et al., 2010)
Climate – acidification interactions
monitoring
pH
Increase in storminess
may depress pH during
7
extreme events and confound
6 .5
recovery from acidification
6
(Hutchins et al, unpub).
1 9 7 9 -1 9 8 4
1 9 8 5 -1 9 8 9
1 9 9 0 -1 9 9 4
1 9 9 5 -2 0 0 1
5 .5
5
4 .5
4
0
100 0
200 0
D is c h a r g e ( l/s )
Climate warming 
increased NO3
CLIMEX Risdalsheia,
Norway
(Van Breemen et al. 1998)
experiments
Water ANC and catchment
soil base saturation for two
emission scenarios and two
forest harvest (biomass
energy) scenarios at the 163
study sites
(Aherne et al. 2008)
modelling
30 00
400 0
CLIMATE CHANGE – ACIDIFICATION
INTERACTIONS
Climate change is a confounding factor in that it can exacerbate
or ameliorate the rate and degree of acidification and recovery,
both with respect to chemical as well as biological effects. The
absence of recovery following reduction in acid deposition,
therefore, may simply be the result of the confounding influence
of climatic variations.
Wright et al., 2010
Climate – toxic substances interaction – effects
of climate change on….
loading of toxic substances to headwater systems
redistribution and uptake of
persistent organic pollutants in
aquatic food-webs
mobilisation of mercury
and methyl mercury in
soils
remobilisation of accumulated heavy metals
and persistent organic pollutants from
polluted soils and subsequent transportation
into aquatic ecosystems
CLIMATE CHANGE – TOXIC SUBSTANCE
INTERACTIONS
Climate changes will be particularly important for pollutants whose environmental
distribution is strongly dependent on temperature, such as organohalogen
compounds. Increases in temperatures will result in greater atmospheric
concentrations of organohalogens by favouring their desorption from land.
Changes in precipitation will modify the rates at which organohalogens are
incorporated into terrestrial waters and ecosystems. At higher atmospheric
concentrations, these compounds will have greater direct impact on the
human population and its health.
Temperature may increase mercury volatilization from land and water
compartments but also oxidation of this metal in the atmosphere which may
favour its deposition. Increased precipitation will likely lead to higher rates
of mercury methylation in soils which will increase the toxicity and
bioaccumulation capacity of this metal in terrestrial ecosystems. Higher
temperature may also reinforce demethylation processes.
Erosion is also a factor for mobilization of metals and POPs and may affect lakes
in remote areas.
Grimalt et al., 2010
MANAGEMENT RESPONSE
A major challenge to incorporate climate change into existing
management strategies or develop new strategies to
accommodate changing climate
Euro-limpacs focused on four main management areas
1.
2.
3.
4.
Use of integrated catchment modelling
Use of indicators
Climate change impacts on restoration and the
reference condition concept
Management and decision support
Management options Integrated Catchment Analysis
and Modelling
Climate change - Expression in Models…
• temperature effects on processes usually included;
• hydrological effects included to some extent;
• plethora of ecological models, but not necessarily
well-linked to relevant driving forces;
• only skimmed the surface of economic change.
Euro-limpacs Integrated Modelling Sites
Models have been applied
to a wide range of
environments across
Europe
Can models be chained to predict the impact of climate change at the
catchment scale?
Integrated modelling in Norway
Global change
model
Regional
downscaling
AOGCM
RCM
T, P
HBV
MAGIC
Hydrologic model
Q
Catchment
process model
NO3
INCA-N
HER, River basin model
SMD
NO3
(Kaste et al. 2006)
+ Wind
speed
FJORD
Q
Fjord model
The Socioeconomic Interface
Can we model the
effects of climate and
agricultural change?
Effects of Climate Change on Nitrate- N (Q05)
with (dotted line) and without enhanced
nitrification
Nitrate as Nitrogen, A2 emissions
12
11
CGCM2
CSIRO
HadCM3
CGCM2S
CSIROS
HadCM3S
mgN/l
10
9
8
7
6
1960
1980
2000
2020
2040
2060
2080
2100
Mitigation
Different methods of mitigating climate change effects
on the River Kennet nitrate
10
8
m gN /l
Nitrate -N
12
6
4
2
Baseline
Fertiliser
Meadows
Combined
Deposition
0
1960
1980
2000
2020
2040
2060
2080
2100
Whitehead et al., 2006
Take Home
Models predict that plausible climate change over Europe
will affect water quantity and quality.
This will cause ecological changes.
The effects differ in detail in different places.
The spatial pattern on a European scale is
? – we are still working on it.
We now have a modelling toolkit:
Downscale, predicting water quality and quantity,
evaluating uncertainty.
-need to apply more widely, test, refine.
8,0
7,5
1986-data; Norway
1995-data; Norway
7,0
pH
6,5
6,0
5,5
5,0
4,5
4,0
-100
-50
0
50
100
ANC cb
Indicators of ecosystem health
What indicator and monitoring systems do we
need to detect the impacts of climate change?
George et al.
In situ lake monitoring
OBJECTIVE - derive improved indicator system for
the assessment of aquatic ecosystem health in the
face of climate change
coloured dissolved organic matter (Round Loch of Glenhead)
0.180
fluorimeter voltage
0.175
0.170
0.165
0.160
0.155
14-Nov05
24-Nov05
04-Dec05
14-Dec05
24-Dec- 03-Jan-06 13-Jan-06
05
Euro-limpacs objectives
• What chemical parameters are best suited as indicators of
climate change?
• Can functional indicators be identified to address climate
change impacts on wetlands, rivers and lakes?
• Can biological indicators of climate change be identified and
can these be used to assess the response of communities
to change?
• Can the different indicator types be linked to provide a
common framework for rivers, lakes and wetlands?
• Can existing assessment and prediction methods for
European freshwater systems be expanded and modified to
address climate change?
Indicators for what?
• Climate Change impacts on lakes, rivers and
wetlands, e.g.
– Indicators for the impact of increasing temperature
– Indicators for the impact of changes in hydromorphology
– Indicators for the impact of increasing eutrophication
– Indicators for the impact of increasing acidification
– Indicators for changes in biodiversity
Monitoring system for the Water Framework
Directive
Restoration
Biological indicators
Metric 1
Metric 2
Metric 3
Supporting physico-chemical
parameters
Metric 1
Metric 2
Restoration
Quality
class
Restoration
Metric 3
Restoration
Supporting hydromorphological
parameters
Metric 1
Metric 2
Restoration
Metric 3
eutrophication
hydromorphology
acidification
other stressors
Climate Change
Aquatic insects and climate change
“..autecological characteristics and distribution patterns of more than 12,000
European freshwater organisms…..macro-invertebrates, fish, diatoms,
macrophytes”
Database contains taxonomic and ecological information
for these organisms (including traits). Distribution maps
can be generated to inform assessment systems
Aquatic insects and climate change
Endemic species
Trichoptera, endemics
Plecoptera, endemics
Ephemeroptera, endemics
Fenno-Scandian
FS
FS
Borealic Uplands
BU
BU
Central Plains
CP
CP
Central Highlands
CH
CH
Italy
Italy
Italy
Iberic-M. Region
I-M
I-M
Carpathians
C
C
Alps
A
A
0
10
20
30
40
50
0
10
20
Percentage of species
30
40
50
0
10
20
30
40
50
Aquatic insects and climate change
Cold stenothermic species
Trichoptera, cold stenothermic
Ephemeroptera, cold stenothermic
Plecoptera, cold stenothermic
Fenno-Scandian
FS
FS
Borealic Uplands
BU
BU
Central Plains
CP
CP
Central Highlands
CH
Italy
Italy
Italy
Iberic-M. Region
I-M
I-M
Carpathians
C
56.9
C
Alps
A
73.0
A
0
10
20
30
40
50
62.6
0
10
20
Percentage of species
30
40
50
CH
0
10
20
30
40
50
Mean monthly
temperatures
Dec - Feb
1971-2000
Mean monthly
temperatures
Dec - Feb
2071-2100
-9.3
-2.3
-2.3
1.6
-0.2-0
3.9-4.0
6.3
9.3
 Problems for cold-stenothermous species
Aquatic insects and climate change
• High number of species sensitive to Climate
Change in the Mediterranean and high mountain
areas
• Low number of sensitive species in the lowlands
and in Northern Europe
• Relatively high number of sensitive species in
Northern Europe for groups with high dispersal
capacity and short life cycle
Lorenz et al., 2010
Climate-and-freshwater.info
Objectives
• Which indicators are presently being used to
assess European freshwater ecosystems?
• Which indicators are best suited to assess and
predict the impact of Climate Change on freshwater
ecosystems?
• Which key indicator species are affected by Climate
Change?
• Which case studies on indicators are available?
Ecosystem types
• Rivers, lakes, wetlands
• Cold, temperate, warm
ecoregions
What does it mean ?
• Tremendous knowledge on ecological preferences
of freshwater biota and on ecosystem response to
Climate Change is available from literature – but
poorly accessible.
• Indicators of various types are useful to detect
ecosystem response to Climate Change.
• Indicators enable predictions of Climate Change
effects on freshwater ecosystems and biota.
Hering et al., 2010
What are the gaps ?
• Integration of Climate Change indicators into
monitoring programmes.
Implications for Water
Framework Directive
•Fish invertebrate and macrophyte
communities will change
•Metrics based on indicator groups and
species will rapidly become redundant
•Ecosystem structure and processbased metrics are likely to become
more relevant
Reference conditions
&
restoration strategies
What are the implications of future climate change for aquatic ecosystem
restoration policies (especially the Water Framework Directive)?
?
The reference state will change through time, and restoration to “good
ecological status” will depend on interactions between recovery processes
and climate change
Battarbee et al 2010
Target setting
• Concepts in restoration ecology:
– Restoration - returning a system to its original state
(i.e. totally unimpacted)
– Rehabilitation - restoring something similar to previous state - similar to
restoration but less perfectionist (Good status rather than High status)
– Replacement - provide something different in place of the disturbed
ecosystem.
• What should we restore?
– ecosystem structure - communities, species, rarities
– habitats
– ecosystem function - biomass, nutrient level, grazing level
Conclusion: compromise?
• May be better to aim for healthy system functioning - not pushing
for exact return of former plant species which may be impossible in
agricultural, lowland regions i.e. cannot get nutrient levels low enough
• Hence functional targets may be best to target shallow lake
restoration -e.g. ‘clear water lake with abundant submerged Elodeid
plants’
Euro-limpacs POSITION PAPER (Battarbee et al., 2009)
What are the implications of climate change
for policy and management of freshwater
ecosystems?
Climate Change Impacts on Freshwater Ecosystems
Martin Kernan, Richard W. Battarbee, Brian Moss
• Details the impact of climate change on
freshwater ecosystems, past, present and future
• Broad coverage: focuses on the key drivers of
aquatic ecosystem change
• Examines interactions between climate change
and other drivers of change
• Integrated full colour images throughout.
• Addresses management aspects
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SOME FUTURE RESEARCH PRIORITIES
Effects on freshwater ecosystems of mitigation and adaptation strategies REFRESH
Effects of climate change and other stressors on aquatic biodiversity –
vulnerability in marginal areas - BIOFRESH
Consideration of socio-economic and cultural/ demographic changes in
response to climate change and how these might impact on freshwater
ecosystems