Lakes in warm ecoregions

– Indicators for Climate Change Impacts –

Interactions between Climate Change, other stressors and the biota are complex. What are the main impacts? Which simple parameters are suited to detect them?

Here we suggest indicators, which reflect the main effects of Climate Change on freshwater ecosystems.

Within the Euro-Limpacs consortium there is an ongoing discussion about the best suited indicators. On this page you find a first selection, which will frequently be updated and improved within 2008.

• Biological parameters

  • Spread of alien species

    Climate Region	Warm
    Ecosystem type	Shallow lakes
    Stressor type	Temperature
    Responding parameter group	Biological parameters
    Responding parameter	Spread of alien species

    Response description

    Higher temperatures often favour alien species. These could be alien fish, macrophyte or macroinvertebrate species.

    Secondary effects

    Strong competitions with native species.

    Specification of relevant ecosystem type

    Relevant for all lakes in warm ecoregions.

    Relevant ecoregion(s) according to Illies

    Iberian Peninsula (1), Italian Peninsula (3), Dinaric Western Balkan (5), Hellenic Western Balkan (6), Eastern Balkan (7)

    Suggested indicator

    Share of alien species in the community.

    Justification of indicator

    This parameter can often be inferred from routine monitoring for the Water Framework Directive.

  • Temperature effects on diatoms

    Climate Region	Warm
    Ecosystem type	Shallow lakes
    Stressor type	Temperature
    Responding parameter group	Biological parameters
    Responding parameter	Temperature effects on diatoms

    Response description

    Increased summer and autumn water temperatures affects diatom productivity and biomass. The response is species specific with abundance of certain diatoms correlated to September and October temperatures.

    Secondary effects

    Changes in phytoplankton biomass and species composition will lead to changes in the entire food web.

    Specification of relevant ecosystem type

    Relevant for all lakes in warm ecoregions.

    Relevant ecoregion(s) according to Illies

    Iberian Peninsula (1), Italian Peninsula (3), Dinaric Western Balkan (5), Hellenic Western Balkan (6), Eastern Balkan (7)

    Suggested indicator

    Water temperature (mean monthly values)

    Justification of indicator

    The mean monthly temperatures reflects overall interannual temperature variation between years.

    Reference(s)

    Catalan, J., S. Pla, M. Rieradevall, M. Felip, M. Ventura, T. Buchaca, L. Camarero, A. Brancelj, P.G.Appleby, A. Lami, J.A. Grytnes, A. Angustí-Panareda & R. Thompson (2002): Lake Red? ecosystem response to an increasing warming in the Pyrenées during the twentieth century. Journal of Paleolimnolimnology 28: 129-145.

  • Temperature effects on macroinvertebrates

    Climate Region	Warm
    Ecosystem type	Shallow lakes
    Stressor type	Temperature
    Responding parameter group	Biological parameters
    Responding parameter	Temperature effects on macroinvertebrates

    Response description

    Increased summer and autumn water temperatures affects sensitive chironomids negatively. Particularly Paratanytarsus austriacus, Heterotrissocladius marcidus, Micropsectra radialis show a negative relationship to summer temperatures.

    Secondary effects

    Changes in community composition and food webs of profundal habitats.

    Specification of relevant ecosystem type

    Relevant for all small lakes in warm ecoregions.

    Relevant ecoregion(s) according to Illies

    Iberian Peninsula (1), Italian Peninsula (3), Dinaric Western Balkan (5), Hellenic Western Balkan (6), Eastern Balkan (7)

    Suggested indicator

    Water temperature (mean monthly values)

    Justification of indicator

    The mean monthly temperatures reflects overall interannual temperature variation between years.

    Reference(s)

    Catalan, J., S. Pla, M. Rieradevall, M. Felip, M. Ventura, T. Buchaca, L. Camarero, A. Brancelj, P.G.Appleby, A. Lami, J.A. Grytnes, A. Angustí-Panareda & R. Thompson (2002): Lake Red? ecosystem response to an increasing warming in the Pyrenées during the twentieth century. Journal of Paleolimnology 28: 129-145.

  • Water temperature effects on food webs

    Climate Region	Warm
    Ecosystem type	Shallow lakes
    Stressor type	Temperature
    Responding parameter group	Biological parameters
    Responding parameter	Water temperature effects on food webs

    Response description

    Increased water temperature generates principal shifts in food webs. As cyprinid planktivorous fish species are supported, large zooplankton species are suppressed and grazing intensity is reduced.

    Secondary effects

    Following reduced grazing intensity, phytoplankton density increases, thus leading to effects similar to eutrophication.

    Specification of relevant ecosystem type

    Most pronounced in shallow lakes but also deep lakes are affected

    Relevant ecoregion(s) according to Illies

    Iberian Peninsula (1), Italian Peninsula (3), Dinaric Western Balkan (5), Hellenic Western Balkan (6), Eastern Balkan (7)

    Suggested indicator

    Proportion of planktivorous and piscivorous fish species; ; proportion of large and small zooplankton species

    Justification of indicator

    Food web structure is well reflected by these two parameters. The share of large zooplankton species determines the effects on phytoplankton, the share of planktivorous species determines the effects on zooplankton.

    Reference(s)

    Petchey, O. L., P. T. McPhearson, T. M. Casey & P. J. Morin (1999): Environmental warming alters food-web structure and ecosystem function. Nature 402: 69 - 72.

• Hydromorphological parameters

  • Temperature

    Climate Region	Warm
    Ecosystem type	Deep lakes
    Stressor type	Temperature
    Responding parameter group	Hydromorphological parameters
    Responding parameter	Temperature

    Response description

    Warmer air temperatures in winter will lead to warmer water temperature. Especially the water temperature in surface layer is dependent on seasonal climatic conditions. Hypolimnetic water temperature is independent of short-term climatic conditions, but heat content is increasing ("climatic memory") and size of the hypolimnion might decrease.

    Secondary effects

    Higher water temperatures might cause earlier oxygen depletion in the hypolimnion, thus reducing its role as a shelter for cold water fish in summer.

    Specification of relevant ecosystem type

    Relevant for all lakes in warm ecoregions.

    Relevant ecoregion(s) according to Illies

    Iberian Peninsula (1), Italian Peninsula (3), Dinaric Western Balkan (5), Hellenic Western Balkan (6), Eastern Balkan (7)

    Suggested indicator

    Water temperature (maximum monthly values)

    Reference(s)

    Ambrosetti, W. & L. Barbanti (1999): Deep water warming in lakes: an indicator of climatic change. Journal of Limnology 58(1): 1-9.

  • Water level

    Climate Region	Warm
    Ecosystem type	Shallow lakes
    Stressor type	Temperature
    Responding parameter group	Hydromorphological parameters
    Responding parameter	Water level

    Response description

    Increased temperature and decreased precipitation in conjunction with intensive water use will decrease water volumes. This will lead to water level imbalances and in many cases to the complete loss of water bodies.

    Secondary effects

    Water level imbalances might change nutrient concentrations and less dilution of pollutants.

    Specification of relevant ecosystem type

    Relevant for all lakes in warm ecoregions. Particularly small lakes may vanish completely.

    Relevant ecoregion(s) according to Illies

    Iberian Peninsula (1), Italian Peninsula (3), Dinaric Western Balkan (5), Hellenic Western Balkan (6), Eastern Balkan (7)

    Suggested indicator

    Lakes surface

    Justification of indicator

    Easy to monitor by remote sensing.

• Physico-chemical parameters

  • Eutrophication

    Climate Region	Warm
    Ecosystem type	Shallow lakes
    Stressor type	Temperature
    Responding parameter group	Physico-chemical parameters
    Responding parameter	Eutrophication

    Response description

    Accelerated growth rate and thus increased biomass due to higher water temperatures will lead to eutrophication through increased deposition of biomass.

    Secondary effects

    Eutrophication in general leads to oxygen depletion of bottom waters.

    Specification of relevant ecosystem type

    Relevant for all lakes in warm ecoregions.

    Relevant ecoregion(s) according to Illies

    Iberian Peninsula (1), Italian Peninsula (3), Dinaric Western Balkan (5), Hellenic Western Balkan (6), Eastern Balkan (7)

    Suggested indicator

    Oxygen concentration of the bottom water in summer

    Justification of indicator

    The parameter is easy to record and often incorporated into routine water chemistry monitoring.

  • Oxygen depletion

    Climate Region	Warm
    Ecosystem type	Shallow lakes
    Stressor type	Temperature
    Responding parameter group	Physico-chemical parameters
    Responding parameter	Oxygen depletion

    Response description

    High temperatures will stimulate phytoplankton growth, which will lead to oxygen depletion of profundal habitats.

    Secondary effects

    Low oxygen intolerant species will vanish

    Specification of relevant ecosystem type

    Relevant for all lakes in warm ecoregions.

    Relevant ecoregion(s) according to Illies

    Iberian Peninsula (1), Italian Peninsula (3), Dinaric Western Balkan (5), Hellenic Western Balkan (6), Eastern Balkan (7)

    Suggested indicator

    Oxygen concentration of the bottom water in summer

    Justification of indicator

    The parameter is easy to record and often incorporated into routine water chemistry monitoring.