Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

High-amplitude fluctuations and alternative dynamical states of midges in Lake Myvatn


Complex dynamics are often shown by simple ecological models1,2 and have been clearly demonstrated in laboratory3,4 and natural systems5,6,7,8,9. Yet many classes of theoretically possible dynamics are still poorly documented in nature. Here we study long-term time-series data of a midge, Tanytarsus gracilentus (Diptera: Chironomidae), in Lake Myvatn, Iceland. The midge undergoes density fluctuations of almost six orders of magnitude. Rather than regular cycles, however, these fluctuations have irregular periods of 4–7 years, indicating complex dynamics. We fit three consumer–resource models capable of qualitatively distinct dynamics to the data. Of these, the best-fitting model shows alternative dynamical states in the absence of environmental variability; depending on the initial midge densities, the model shows either fluctuations around a fixed point or high-amplitude cycles. This explains the observed complex population dynamics: high-amplitude but irregular fluctuations occur because stochastic variability causes the dynamics to switch between domains of attraction to the alternative states. In the model, the amplitude of fluctuations depends strongly on minute resource subsidies into the midge habitat. These resource subsidies may be sensitive to human-caused changes in the hydrology of the lake, with human impacts such as dredging leading to higher-amplitude fluctuations. Tanytarsus gracilentus is a key component of the Myvatn ecosystem, representing two-thirds of the secondary productivity of the lake10 and providing vital food resources to fish and to breeding bird populations11,12. Therefore the high-amplitude, irregular fluctuations in midge densities generated by alternative dynamical states dominate much of the ecology of the lake.

Your institute does not have access to this article

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Population dynamics of T. gracilentus in Myvatn.
Figure 2: Simulated dynamics of the model given by Box 1 equations (1)–(3) for 50 generations.
Figure 3: Dynamics of the midge–algae–detritus model depending on resource input rate, c , and detritus retention, d.


  1. May, R. M. Simple mathematical models with very complicated dynamics. Nature 261, 459–467 (1976)

    ADS  CAS  Article  Google Scholar 

  2. Hastings, A., Hom, C. L., Ellner, S., Turchin, P. & Godfray, H. C. J. Chaos in ecology: is Mother Nature a strange attractor? Annu. Rev. Ecol. Syst. 34, 1–33 (1993)

    Article  Google Scholar 

  3. Dennis, B., Desharnais, R. A., Cushing, J. M., Henson, S. M. & Costantino, R. F. Estimating chaos and complex dynamics in an insect population. Ecol. Monogr. 71, 277–303 (2001)

    Article  Google Scholar 

  4. Becks, L., Hilker, F. M., Malchow, H., Jurgens, K. & Arndt, H. Experimental demonstration of chaos in a microbial food web. Nature 435, 1226–1229 (2005)

    ADS  CAS  Article  Google Scholar 

  5. Bjornstad, O. N. & Grenfell, B. T. Noisy clockwork: Time series analysis of population fluctuations in animals. Science 293, 638–643 (2001)

    CAS  Article  Google Scholar 

  6. Dwyer, G., Dushoff, J. & Yee, S. H. The combined effects of pathogens and predators on insect outbreaks. Nature 430, 341–345 (2004)

    ADS  CAS  Article  Google Scholar 

  7. Turchin, P. Complex Population Dynamics: a Theoretical/Empirical Synthesis (Princeton Univ. Press, Princeton, NJ, 2003)

    MATH  Google Scholar 

  8. Hanski, I., Turchin, P., Korpimaki, E. & Henttonen, H. Population oscillations of boreal rodents—regulation by mustelid predators leads to chaos. Nature 364, 232–235 (1993)

    ADS  CAS  Article  Google Scholar 

  9. Scheffer, M., Carpenter, S., Foley, J. A., Folke, C. & Walker, B. Catastrophic shifts in ecosystems. Nature 413, 591–596 (2001)

    ADS  CAS  Article  Google Scholar 

  10. Lindegaard, C. & Jónasson, P. M. Abundance, population dynamics and production of zoobenthos in Lake My´vatn, Iceland. Oikos 32, 202–227 (1979)

    Article  Google Scholar 

  11. Gudbergsson, G. Arctic charr in Lake Myvatn: the centennial catch record in the light of recent stock estimates. Aquatic Ecol. 38, 271–284 (2004)

    Article  Google Scholar 

  12. Gardarsson, A. & Einarsson, A. Resource limitation of diving ducks at Myvatn: Food limits production. Aquatic Ecol. 38, 285–295 (2004)

    Article  Google Scholar 

  13. May, R. M. Thresholds and breakpoints in ecosystems with a multiplicity of stable states. Nature 269, 471–477 (1977)

    ADS  Article  Google Scholar 

  14. Noy-Meir, I. Stability of grazing systems: an application of predator–prey graphs. J. Ecol. 63, 459–481 (1975)

    Article  Google Scholar 

  15. Scheffer, M., Hosper, S. H., Meijer, M.-L., Moss, B. & Jeppesen, E. Alternative equilibria in shallow lakes. Trends Ecol. Evol. 8, 275–279 (1993)

    CAS  Article  Google Scholar 

  16. Persson, L. et al. Culling prey promotes predator recovery—alternative states in a whole-lake experiment. Science 316, 1743–1746 (2007)

    ADS  CAS  Article  Google Scholar 

  17. Carpenter, S. R. Regime Shifts in Lake Ecosystems: Patterns and Variation (International Ecology Inst., Oldendorf/Luhe, Germany, 2003)

    Google Scholar 

  18. Henson, S. M., Costantino, R. F., Desharnais, R. A., Cushing, J. M. & Dennis, B. Basins of attraction: population dynamics with two stable 4-cycles. Oikos 98, 17–24 (2002)

    Article  Google Scholar 

  19. Ives, A. R., Gross, K. & Jansen, V. A. A. Periodic mortality events in predator–prey systems. Ecology 81, 3330–3340 (2000)

    Google Scholar 

  20. King, A. A. & Schaffer, W. M. The rainbow bridge: Hamiltonian limits and resonances in predator–prey models. J. Math. Biol. 39, 439–469 (1999)

    MathSciNet  CAS  Article  Google Scholar 

  21. Jansen, V. A. A. & Sabelis, M. W. Outbreaks of colony-forming pests in tri-trophic systems: consequences for pest control and the evolution of pesticide resistance. Oikos 74, 172–176 (1995)

    Article  Google Scholar 

  22. Klebanoff, A. & Hastings, A. Chaos in three species food chains. J. Math. Biol. 32, 427–451 (1994)

    MathSciNet  Article  Google Scholar 

  23. Kendall, B. E. et al. Why do populations cycle? A synthesis of statistical and mechanistic modeling approaches. Ecology 80, 1789–1805 (1999)

    Article  Google Scholar 

  24. Ingvason, H. R., Olafsson, J. S. & Gardarsson, A. Food selection of Tanytarsus gracilentus larvae (Diptera: Chironomidae): an analysis of instars and cohorts. Aquatic Ecol. 38, 231–237 (2004)

    Article  Google Scholar 

  25. Einarsson, A., Gardarsson, A., Gislason, G. M. & Ives, A. R. Consumer–resource interactions and cyclic population dynamics of Tanytarsus gracilentus (Diptera: Chironomidae). J. Anim. Ecol. 71, 832–845 (2002)

    Article  Google Scholar 

  26. Gardarsson, A. et al. Population fluctuations of chironomid and simuliid Diptera at Myvatn in 1977–1996. Aquatic Ecol. 38, 209–217 (2004)

    Article  Google Scholar 

  27. Kjaran, S. P., Hólm, S. L. & Myer, E. M. Lake circulation and sediment transport in Lake Myvatn. Aquatic Ecol. 38, 145–162 (2004)

    Article  Google Scholar 

  28. Harvey, A. C. Forecasting, Structural Time Series Models and the Kalman Filter (Cambridge Univ. Press, Cambridge, 1989)

    Google Scholar 

  29. McGovern, T. H., Perdikaris, S., Einarsson, A´. & Sidell, J. Coastal connections, local fishing, and sustainable egg harvesting: patterns of Viking Age inland wild resource use in My´vatn district, Northern Iceland. Environ. Archaeol. 11, 187–205 (2006)

    Article  Google Scholar 

  30. Ives, A. R., Dennis, B., Cottingham, K. L. & Carpenter, S. R. Estimating community stability and ecological interactions from time-series data. Ecol. Monogr. 73, 301–330 (2003)

    Article  Google Scholar 

Download references


We thank K. C. Abbott, M. Duffy, K. J. Forbes, R. T. Gilman, J. P. Harmon and members of Zoo/Ent 540, Theoretical Ecology, University of Wisconsin – Madison, for comments on the manuscript. V.A.A.J. thanks R. A. Jansen-Spence for the time to do this research. This work was funded in part by National Science Foundation grants to A.R.I., and grants from the Icelandic Research Council and the University of Iceland Research Fund to A.E. and A.G.

Author Contributions A.E. and A.G. oversaw the data collection and are responsible for the long-term study on midge dynamics in Myvatn. A.E. and A.R.I. conceived the midge–algae–detritus model, and A.R.I. performed statistical analyses. V.A.A.J. and A.R.I. performed the mathematical analyses of the midge–algae–detritus model.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Anthony R. Ives.

Supplementary information

Supplementary Information

The file contains Supplementary Notes, Supplementary Figures S1-S10 with Legends and Supplementary Methods and Supplementary Table S1. (PDF 480 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Ives, A., Einarsson, Á., Jansen, V. et al. High-amplitude fluctuations and alternative dynamical states of midges in Lake Myvatn. Nature 452, 84–87 (2008).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing