BIODIVERSITY IN ALPINE PONDS: AN INDICATOR OF CLIMATE WARMING?
Beat Oertli1 , Véronique Rosset1 & Anthony Lehmann2
11 University of Applied Sciences Western Switzerland University of Applied Sciences Western Switzerland EIL, EIL, hepiahepia, Department of Nature Management, , Department of Nature Management, CH CH --1254 1254 JussyJussy--Geneva, Switzerland Geneva, Switzerland [email protected]@hesge.ch
2 University of Geneva Climatic change and climate impacts research,
CH - 1227 Carouge, Switzerland
ContextContext
Climate warming has (and will have) an impact on biodiversityworldwide (Thomas et al. 2004, Nature 411) :
0
5
10
15
20
25
30
35
40
J F M A M J J A S O N D
% 2005
For example:Species distribution shifts: upwards and northwards
Changes in phenology
Crocothemiserythrea
Coenagrion puella
For cold stenoterm species
• Reasons for this move: – in direct response to
increasing temperature (Parmesan & Yohe, 2003; Root et al., 2003),
– or in combination with other changes (Pounds et al., 1999; Still et al., 1999)
UpslopeUpslope distribution shifts of distribution shifts of speciesspecies rangerange
Ex.: Dragonfly A. caerulea
Evidences from several mountain systems
• In Russia, subalpine forests have shifted upwards by 60-80 m in the Southern Urals (lasts 70 years) (Moiseev & Shiyatov 2003)
• Similar up- and northward shifts of treelineecotones have been reported from NorthAmerica, Scandinavia and Siberia.
Upslope distribution shifts: advance of treelines
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Historic photographs of treelines in the Southern Ural (1929, below 1999).Source: Stepan Shiyatov
Potential increase in the elevation of the tree line, assuming a 4·5 °C rise in temperature over 100 years .Grace et al. 2002, Annals of Botany 90
ConsequenceConsequence: change in : change in biodiversitybiodiversity altitudinal patternsaltitudinal patterns
Present trend (althought exceptions):Decreasing regional species richness with increasing altitude
From
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ity, A
n In
trodu
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n. •A shift is expected in the future
•On-going research focuses on the regionalscale
•Little is known about consequences on local diversity (e.g. ecosystem species richness)
AtAt the local the local scalescale: : increaseincrease in in speciesspecies numbernumber
Example: Vascular plants in the High Alps (2900 to 3450 m): Plant species richness already has increased.
11.4 species 12.7 species
10 years
Mean of 362 quadrats(1 x 1 m)
Pauli et al. 2007; Global Change Biology 13
43% of species expanded to new plots (5% decreased)
Example: Gnaphalium supinum: from38 plots to 112 plots
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Local scale investigated here: the pond Local scale investigated here: the pond
Pond: a definitionA small waterbodySize: from one metre squared to a few hectares Depth: from a few centimetres to many metresSome hold water all year round, but many go through
cycles of wetting and dryingOrigin: either man-made or natural
www.europeandponds.org
(Oertli et al. 2005, Aquatic Conservation 15)
Forel (1904): « a pond is a lake, lacking its aphotic zone »
What is a pond? What is a pond?
Ponds are exceptionally numerous! Ponds are exceptionally numerous!
Downing et al. 2006. Limnol.Oceanogr. 51: 2388-2397
Have been forgotten in global assessments
• Downing et al. (2006) have estimated their number:
– > 300 millions– total surface : 1,7
millions de km2
How How manymany ponds in ponds in SwitzerlandSwitzerland??
- 32’000 ponds (size between 100 m2 and 5 ha)
- 365 lakes (> 5 ha)
Digital mapVECTOR25
(topic« lakes » )
Areas with highest pond density in the Swiss AlpsAreas with highest pond density in the Swiss Alps(20 to 30 ponds /km(20 to 30 ponds /km22))
« In Hublen » (aroundSeebodensee), Sustenpass BE
Grimselpass , Totesee(Oberwald, Rhonegletscher, VS)
Macun, SwissNational Park (GR)
Minssieux 2009, in prep.
Glacier et Lapies de Tsanfleuron(Les Diablerets, Savièse-Sion, VS)
Natural origins in the alpsNatural origins in the alps
last glacial last glacial retreatretreat
Le Mongeron, FR
snowsnow meltingmelting
Macun, GR
fluvial fluvial dynamicdynamic
Arvins, GR
Ponds: Ponds: modelsmodels for for assessingassessing biodiversitybiodiversity changeschanges
Ponds as a model because:
Low α diversity. Small → Simple community structure (De Meester et al. 2005, Aquat. Conserv. 15),particularly in altitude.
High β and γ diversities (Oertli et al. 2002, Biol. Conserv. 104; Williams et al.2004, Biol.Conserv. 115; Angélibert et al. 2006, Arch. Sc. 59), i.e. with a largecontribution to the regional diversity.
Freshwater biodiversity is particularlyendangered (Dudgeon et al. 2006, Biol. Rev. 81)
Extremely numerous andlargely distributed in the landscape: “= replicates”
Two main questions on alpine pond biodiversity :1. Are quantitative changes expected (increase in species richness)?2. Are qualitative changes expected? Which would be the losers and/or winners,
i.e. the species changes in the communities?
Study sites: about 100 ponds, covering a large Study sites: about 100 ponds, covering a large range of thermal conditionsrange of thermal conditions
Switzerland
Pond size: from 30 to 80’000 m2
Altitude: from 250 to 2800 m.asl
- Standardized field sampling based on the PLOCH method (Oertli et al. 2005, Aqu. Conserv.)
Field sampling & modelisation (GAMs)
Biodiversity (species richness)
Aquatic vegetation
Snails
Beetles
Dragonflies (adults)
Amphibia
Environment- Connectivity- Agriculture in watershed- % environment forested
Environmental variables (15 selected from 100)
Pond morphometry- Area- Shoreline shade- Mean depth- Shoreline development
Water physico-chemistry- Conductibility- Trophy- Transparency
Others- Age
Biology- Floating/submerged
vegetation coverage (%)- Fishes
Climate- Mean annual air T°
GAMs
- Modelling: GAMs. GRASP (Lehmann et al. 2003, Ecological Modelling 157)
Predictive models have been developed and used
GAMsMODELS
For each pond, 3 predictions for 2100:
IN
OUT
Changes in six otherenvironmental variables:
Predicted species richnessfor 2100
+ 3.4 °C
nr1 nr2 nr3Increase in temperature(scenario A2)
no min max
Conductivity (winter measures)
Water transparency in summer (Snell tube)
Trophic class based on P, N and conductivity
Proportion of pond area covered by submerged vegetation
Proportion of pond area covered by floating vegetation
Proportion of agriculture in the catchment area
(variables expected to change during this century)
Predictions of potential changes in local diversity(pond species richness) + + + +
In the whole Switzerland:
Rosset et al. (2008) Verh Int Assoc Limnol. 30
Rosset et al. (submitted)
Pond diversity will clearly increase with climate warming.
predictions
87 to 104%
The The increaseincrease willwill bebe particularlyparticularly highhigh in altitude.in altitude.
+ + + +
n = 16n = 15
n = 55 n = 27
32 to 75% 77 to 136%
73 to 170% 135 to 478%
predictions predictions
The predicted species enrichment masks changes in species composition (and extinction events)
Colonizations: stenotherm or
eurytherm species(from lower altitudes)
Extinctions: cold stenothermal
species (=« alpine »)
Alpine pondAlpine pond
Aeshna caerulea
DragonfliesDragonflies: the winners and the losers in alpine ponds: the winners and the losers in alpine ponds
Source of information: Swiss data bank (CSCF &
CRSF) + taxonomicspecialists
MountainThermal gradient
Lowland
Dragonflies: 7 losers (at risk of local extinction)
Aeshna caerulea
Somatochlora alpestris
Coenagrion hastulatumwww.pbase.com/stureh
Leucorrhinia dubia
Aeshna juncea
Aeshna subarctica
Somatochlora artica
12% of Swiss species pool
Dragonflies: the winners (Dragonflies: the winners (colonisationcolonisation is soon expected)is soon expected)
E.cyathigerum
L. quadrimaculata
9 species, but all other lowland species on a longer term (88% CH)
Aquatic vegetation: 11 losers (5%)Thermal preferences of flora species
Source of information: Swiss data bank (CSCF & CRSF) + taxonomic specialists
Saxifraga stellaris
http://papounet.wifeo.com
Epilobium alsinifoliumhttp://www.plant-identification.co.uk
Juncus filiformishttp://edu.taivalkoski.fi
Sparganium angustifoliumhttp://www.plant-identification.co.uk
Carex frigidahttp://www.florealpes.com
www.digitalnature.org/flora Eriophorum scheuchzeri
Aquatic beetles: 6 losers (5%)
Source of information: taxonomic specialists
Ilybius erichsoni
From: www.zin.ru
-Ilybius erichsoni
-Agabus lapponicus
-Stictotarsus griseostriatus
-Hydroporus foveolatus
-Hydroporus nigellus
-Hydroporus sabaudus
Hydroporus foveolatus
Mountain
Groups with only winners
Thermal gradient
Snails
Amphibia
Lowland
Source of information: Swiss data bank (CSCF & CRSF) + taxonomic specialists
Snails and Amphibia:no cold stenothermspecies
In syntheses: more winners than losers in altitude
• More colonization events than extinctions are expected.
Candidates for colonizations:• The majority of the currentSwiss regional species pool• They are readily available.
Candidates for extinctions:• A minority of the current Swissregional species pool.
Enallagmacyathigerum
95% 100% 100%88%95%
5% 0% 0%12%5%
Nymphoides peltata
From: www.countrysideinfo.co.uk
In the reality, the pond species enrichment will be lower than predicted, but still high.
• The predictions represent a potential, i.e. the upper range of what might be the future pond diversity.
• The predicted changes will be moderated by other processes, as :
(i) physical changes (including hydrology and availability of habitats)
(ii) colonization and dispersal abilities of species(snails ≠ dragonflies)
(iii) biological interactions(competition, predation …)
PerspectivesPerspectives
• Pond diversity constitutes an excellent sentinelsystem for monitoring climate warming effects atthe local scale.
→ Should be used as a bioindicator of climatewarming in long-term monitoring
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±200 0 200100 MètresPlan de situation © MVA Grison
- 36 ponds - 3 streams
•
- Monitored since 2002
Ex: Swiss National Park
OnOn--goinggoing monitoring in the monitoring in the SwissSwiss National ParkNational Park
M20
M15M8t
Robinson & Oertli 2009, eco.mont 1
Magnitude of the Magnitude of the regionalregional richnessrichness ((MacunMacun cirque):cirque):
Swiss lowland ponds
… a particularly low richness (at species or family level)
Macun ponds
3838 lentic taxa
lentic taxa17+4
7 1
1
62
Compared with lowland ponds…
““Thanks for your Thanks for your attentionattention””
THANKS ALSO: to the “PLOCH” team (University of Geneva), to the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), to the Swiss Centre for fauna cartography (CSCF) and Swiss Centre of floristic network (CRSF), to the Federal Office for the Environment (OFEV), to many Swiss states, to HES-SO (RCSO RealTech), to the Research Commission of the Swiss National Park