Download Changes in freshwater ecosystems due to climate change

Changes in freshwater
ecosystems
due to climate change Which adaptation?
Daniel Gerdeaux, INRA Thonon, Dpt EFPA
http://www.clermont.inra.fr/urep/accae
Restoration, protection …. and adaptation?
2000 : Water Framework Directive with the following key aims:
•expanding the scope of water protection to all waters, surface
waters and groundwater
•achieving "good status" for all waters by a set deadline
•water management based on river basins
•"combined approach" of emission limit values and quality
standards
•getting the prices right
•getting the citizen involved more closely
•streamlining legislation
Ecological status of French waterbodies
(deviation from Reference. conditions)
indeterminate
Very bad
Reference
conditions
Insignificantly
disturbed biology,
hydro-morphology
and physicochemistry
(Wallin et al, 2003)
high
bad
2015-2027
good
RESTORATION
WFD
An example : Lake Geneva
Climate Change : - warming
- hydrology
- solar radiation
100
Annual meam Water temperature(°C)
moderate
Lake Geneva 5m below the surface
13
12
11
10
1970
1975
1980
1985
1990
1995 2000
2005
80
5500
annual solar radiation on Lake Geneva (MJ.m-2)
60
5000
P ot (µgP/l
4500
)
40
4000
3500
20
1980
0
1960
1965
1970
1975
1980
1985
1990
1995
2000
Several parameters are changing
1985
1990
1995
2000
2005
2010
Consequences on physico-chemical parameters
Lack of overturns , then anoxy at
the bottom in Lake Geneva
Start of thermal stratification
26 june
12
12 june
Oxygen (mg/l)
10
29 may
15 may
8
6
4
1 may
1970
1980
1990
2
2000
0
1986
1990
1994
1998
An example : Lake Geneva
Some variations or changes due to : reoligotrophication, climate change, ….
Biomasse (µg.l-1)
2000
1974-1985
1986-1991
1500
1000
500
0
J
F
M
A
M
J
Jt
A
S
O
N
D
J
F
M
A
M
J
Jt
A
S
O
N
D
1500
1000
500
0
> 1991
2500
2000
1500
1000
spring
fall
summer
Phytoplankton in Lake Geneva:
changes in seasonality, the
phytoplankton assemblages and the
functional associations of species
(Reynolds et al 2002)
What is due to
-reoligotrophication
-climate change
-fishery….. ?
500
0
J
F
M
M
J
A
F
Lm
R
W2
100%
90%
Jt
A
S
O
N
B
G
Lo
S1
X1
D
C
H1
M
T
Y
D
J
N
U
Z
E
K
P
W1
Non classé
80%
70%
60%
50%
40%
30%
20%
10%
20
08
20
06
20
04
20
02
20
00
19
98
19
96
19
94
19
92
19
90
19
88
19
86
19
84
19
82
19
80
19
78
19
76
0%
19
74
Biomassemoyenneannuelle(µg/L)
A
Today the upper layers (0-30m) in Lake Geneva are almost oligotrophic while before
1986 the P depletion in the upper layers was brief and not deep
Orthophosphate - PO4 (µgP/l) - Lake Geneva
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
An example : Lake Geneva
Changes in Lake Geneva (reoligotriphication, warming, stocking)
favourable to whitefish (Coregonus lavaretus) unfavorable to arctic
char (Salvelinus arcticus) two cold water species
(Arctic char reproduction is not possible above 7°C during ovogenesis)
A better match between
egg hatching and
zooplankton dynamics
Witefish
catches in Lake GENEVA
strength
of cohort
350
300
250
70’s
200
Algae
150
Zooplankton
eggs
100
50
100
90
80
70
60
50
40
30
20
10
.
1993
.
1996
.
1999
1994
1997
.
2000
.
2002
.
R²= 0.543
1995
2001
.
1998
0
5..7 5..8 5..9 6.. 0 6. 1 6..2 6..3 6..4 6..5 6. 6
2000’s
mean annual temperature at 100 m
Alguae
1970
1974
1978
1982
1986
1990
1994
1998
Zooplankton
eggs
Jan. Feb. Mar April May Jun Jul. Augt Sep. Oct. Nov.Déc.
Two “cold species” two different responses
• Changes due to numerous causes
•Habitats deterioration
•Eutrophication and reoligotrophcation
•Management of resources, overexploitation
•Pollution
•Invasive species
•Climate
•Climate changes influence directly the biodiversity (stenothermy) and indirectly by
their influence on other causes of deterioration
•Difficult to understand the role of climate change separately from the effects of other
environmental, social and economic changes that affect waterbodies
•KEY POINTS :
•Biological indicators of warming are useful tools. Eco-physiological studies on new
indicators are necessary : Direct effects
•But the responses of ecosystems to a stressor are often not linear
•The impacts of climate change will be different at different scales across different
regions.
•necessity to maintain and extend high quality, long-term monitoring to better
understand the key processes that control system responses to climate change and to
take into account the inter-annual variations in ecosystems AND THE UNCERTAINTY
•Biological indicators of warming are useful tools. Eco-physiological studies on new
indicators are necessary :
lists of biological indicators : http://www.climate-and-freshwater.info/
Indicators potentially suited to detect the effects of Climate Change on
European aquatic ecosystems
Aquatic species which are affected by (or benefiting from) Climate Change
Need for more (better?) biological indicators
Exploration of the influence of global warming on the chironomid community in a manipulated shallow
groundwater system.
Guillaume Tixier, Kevin P. Wilson,D. Dudley Williams. 2008
examined the response of the groundwater chironomid community : warming decreased the total
abundance of chironomids
whereas no significant change in taxonomic richness was apparent.
taxon composition changed markedly during both the manipulation and the recovery period. Whereas
Heterotrissocladius disappeared during the manipulation in the treatment block, other coldstenothermal
taxa such as Micropsectra, Parametriocnemus and Heleniella remained unaffected.
Conversely, Corynoneura, Polypedilum and Thienemannia gracilis disappeared but were not reported as
coldstenothermal. The chironomid community composition in the system changed from a
Heterotrissocladius, Brillia, and Tanytarsini-dominated community during the pre-manipulation towards one
dominated by Parametriocnemus, Polypedilum, Orthocladius/Cricotopus and Corynoneura during the
recovery. Although increased temperature had a strong effect, chironomid occurrence was also influenced by
a number of other abiotic variables, such as dissolved oxygen, depth, ammonia concentration and TDS (Total
dissolved solids).
•The responses of ecosystems to a
stressor are often not linear :
Analysis of the trophic index shows that
phytoplankton communities exhibit highly
non-linear responses to eutrophication in
Norwegian lakes. Reference lakes
are characterized by very similar TIs despite
having considerable variation in total
phosphorus and chlorophyll a
concentrations. TI exhibits a non-linear
distribution along the eutrophication
gradient which separates unimpacted from
impacted sites in the study area. We further
show that TI exhibits smaller seasonal
variations than chlorophyll a, making it a
more reliable indicator for lake monitoring.
Few similar data on the
responses to warming
Trophic index (TI) as a function of total phosphorus (TP; upper
panel) and chlorophyll a (Chl a, lower panel). Left: Black dots represent
samples from reference lakes, grey dots others. Horizontal dashed line
gives the upper 95th percentile of the TI from reference lakes (= 2.11).
Right: Same data, with quantile regression, showing the median (bold
Performance of a new phytoplankton composition metric along a eutrophication
gradient in Nordic lakes. Ptacnik , Solimini,Brettum, Hydrobiologia (2009) 633:75–82 line) as well as the 5th and 95th percentiles (dashed lines).
•What is the influence of climate change
on shifts in ecosystems? Extreme events
and “catastrophic shifts”
A graphical model of alternative stable states in shallow lakes on the basis
of three assumptions: (1) turbidity of the water increases with the nutrient level; (2)
submerged vegetation reduces turbidity; and (3) vegetation disappears when a critical
turbidity is exceeded. In view of the first two assumptions, equilibrium turbidity can be
drawn as two different functions of the nutrient level: one for a vegetation-dominated
situation, and one for an unvegetated situation. Above a critical turbidity, vegetation
will be absent, in which case the upper equilibrium line is the relevant one; below this
turbidity the lower equilibrium curve applies. As a result, at lower nutrient levels, only
the vegetation-dominated equilibrium exists, whereas at the highest nutrient levels,
there is only an unvegetated equilibrium. Over a range of intermediate nutrient levels,
two alternative equilibria exist: one with vegetation, and a more turbid one without
vegetation, separated by a (dashed) unstable equilibrium.
External conditions affect the resilience of multi-stable ecosystems to
perturbation. The bottom plane shows the equilibrium curve .The
stability landscapes depict the equilibria and their basins of attraction
at five different conditions. Stable equilibria correspond to valleys; the
unstable middle section of the folded equilibrium curve corresponds
to a hill. If the size of the attraction basin is small, resilience is small
and even a moderate perturbation may bring the system into the
alternative basin of attraction.
Catastrophic shifts in ecosystems
Marten Scheffer, Steve Carpenter, Jonathan A. Foley, Carl Folke & Brian Walkerk, Nature
2001
•The impacts of climate change will be different
at different scales across different regions.
The consequences of warming will be different in Lake Geneva (309m red line)
and in Lake Annecy (65m, blue line)
6.0
Température °C
5.8
5.6
5.4
5.2
5.0
4.8
4.6
4.4
4.2
4.0
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
Années
•The impacts of climate change will be different
at different scales across different regions.
The consequences of warming will be different in Lake Ammersee
and in Lake Annecy
Mean annual air temperature
Bottom water temperature
Surface maximum water temperature
T °C
24
20
16
12
8
4
Lake Ammersee
Lake Annecy
Winters without overturn and oxygenation of the bottom
Danis, P.A., von Grafenstein, U., Masson-Delmotte, V., Planton, S., Gerdeaux, D. Moisselin, J.M. (2004): Vulnerability of
two European lakes in response to future climatic changes. Geophysical Research Letters 31.
•The impacts of climate change will be different at
different scales across different regions
•but similar interannual variability
In Muggelsee, the phytoplankton biovolume during late
winter/early spring was related to the NAO index. In Lake
Constance, where phytoplankton growth was inhibited by
intense downward mixing during all years studied, this was not
the case. However, in both lakes, interannual variability in
water temperature, in Daphnia spring population dynamics and
in the timing of the clear-water phase, were all related to the
interannual variability of the NAO index. The Daphnia spring
population dynamics and the timing of the clear-water phase
appear to be synchronized by the NAO despite large
differences between the lakes in morphometry, trophic status
and hushing and mixis regimes, and despite the great distance
between the lakes (similar to 700 km). This suggests that a
great variety of lakes in central Europe may possibly have
exhibited similar interannual variability during the last 20 years.
Straile & Adrian GLOBAL CHANGE BIOLOGY
2000
•The impacts of climate change will be different at
different scales across different regions
•but similar interannual variability
It is necessary to maintain and extend high quality, long-term monitoring
to better understand the key processes that control system responses to
climate change and to take into account the inter-annual variations in
ecosystems (for example influence of NAO on European lakes) : a
database to archive key temporal data-sets will be very useful.
Example : Lake Dynamics Monitoring Stations in UK
http://www.eurolimpacs.ucl.ac.uk/
Conclusion :
•Biological indicators of warming are essential tools :
•need more studies for a quantitative understanding of
climate change effects on structure and functioning of
freshwater ecosystems
•The impacts of climate change will be different at different scales
across different regions. (ecoregions)
•The responses of ecosystems to a stressor are often not linear
•Extreme events will be more frequent
•necessity to maintain and extend high quality, long-term
monitoring to better understand the key processes that
control system responses to climate change and to take into
account the inter-annual variations in ecosystems and the
uncertainty : adaptation of the baseline of reference
conditions
Conclusion :
Implications of climate change for restoration and
protection measures
Measures should be fully climate resilient
No regret measures
Avoid measures that will fail under future climatic conditions
Developing solutions to build resilience
Thanks for your attention