Skip to main content

Thank you for visiting nature.com. 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.

Flow regime alteration degrades ecological networks in riparian ecosystems

Abstract

Riverine ecosystems are governed by patterns of temporal variation in river flows. This dynamism will change due to climate change and the near-ubiquitous human control of river flows globally, which may have severe effects on species distributions and interactions. We employed a combination of population modelling and network theory to explore the consequences of possible flow regime futures on riparian plant communities, including scenarios of increased drought, flooding and flow homogenization (removal of flow variability). We found that even slight modifications to the historic natural flow regime had significant consequences for the structure of riparian plant networks. Networks of emergent interactions between plant guilds were most connected at the natural flow regime and became simplified with increasing flow alteration. The most influential component of flow alteration was flood reduction, with drought and flow homogenization both having greater simplifying community-wide consequences than increased flooding. These findings suggest that maintaining floods under future climates will be needed to overcome the negative long-term consequences of flow modification on riverine ecosystems.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Conceptual diagram outlining the workflow used in the analysis, from data collection to projection.
Fig. 2: Examination of riparian plant networks across a spectrum of possible flow regime futures.
Fig. 3: Summary metrics of full ecological networks spanning the spectrum of flow extremes from extreme drought to flood.
Fig. 4: Degree (number of links connected to the node) of each network node in relation to flow state.

References

  1. Poff, N. L. et al. The natural flow regime. Bioscience 47, 769–784 (1997).

    Article  Google Scholar 

  2. Nilsson, C., Reidy, C. A., Dynesius, M. & Revenga, C. Fragmentation and flow regulation of the world’s large river systems. Science 308, 405–408 (2005).

    Article  CAS  PubMed  Google Scholar 

  3. Zarfl, C., Lumsdon, A. E., Berlekamp, J., Tydecks, L. & Tockner, K. A global boom in hydropower dam construction. Aquat. Sci. 77, 161–170 (2014).

    Article  Google Scholar 

  4. Poff, N. L., Olden, J. D. J., Merritt, D. M. & Pepin, D. M. Homogenization of regional river dynamics by dams and global biodiversity implications. Proc. Natl Acad. Sci. USA 104, 5732–5737 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. Flanagan, N. E., Richardson, C. J. & Ho, M. Connecting differential responses of native and invasive riparian plants to climate change and environmental alteration. Ecol. Appl. 25, 753–767 (2015).

    Article  PubMed  Google Scholar 

  6. Naiman, R. J. & Décamps, H. The ecology of interfaces: riparian zones. Annu. Rev. Ecol. Syst. 28, 621–658 (1997).

    Article  Google Scholar 

  7. Reynolds, L. V., Shafroth, P. B. & Poff, N. L. Modeled intermittency risk for small streams in the Upper Colorado River Basin under climate change. J. Hydrol. 523, 768–780 (2015).

    Article  Google Scholar 

  8. Lu, X. et al. Drought rewires the cores of food webs. Nat. Clim. Change 6, 875–878 (2016).

    Article  Google Scholar 

  9. Ledger, M. E., Brown, L. E., Edwards, F. K., Milner, A. M. & Woodward, G. Drought alters the structure and functioning of complex food webs. Nat. Clim. Change 3, 223–227 (2012).

    Article  Google Scholar 

  10. Lytle, D. A., Merritt, D. M., Tonkin, J. D., Olden, J. D. & Reynolds, L. V. Linking river flow regimes to riparian plant guilds: a community-wide modeling approach. Ecol. Appl. 27, 1338–1350 (2017).

    Article  PubMed  Google Scholar 

  11. Lytle, D. A. & Poff, N. L. Adaptation to natural flow regimes. Trends Ecol. Evol. 19, 94–100 (2004).

    Article  PubMed  Google Scholar 

  12. Strona, G. & Lafferty, K. D. Environmental change makes robust ecological networks fragile. Nat. Commun. 7, 1–7 (2016).

    Google Scholar 

  13. Ings, T. C. et al. Ecological networks — beyond food webs. J. Anim. Ecol. 78, 253–269 (2009).

    Article  PubMed  Google Scholar 

  14. Thebault, E. & Fontaine, C. Stability of ecological communities and the architecture of mutualistic and trophic networks. Science 329, 853–856 (2010).

    Article  CAS  PubMed  Google Scholar 

  15. Dunne, J. A., Williams, R. J. & Martinez, N. D. Network structure and biodiversity loss in food webs: robustness increases with connectance. Ecol. Lett. 5, 558–567 (2002).

    Article  Google Scholar 

  16. Poisot, T., Stouffer, D. B. & Gravel, D. Beyond species: why ecological interaction networks vary through space and time. Oikos 124, 243–251 (2015).

    Article  Google Scholar 

  17. Thompson, P. L. & Gonzalez, A. Dispersal governs the reorganization of ecological networks under environmental change. Nat. Ecol. Evol. 1, 0162 (2017).

    Article  PubMed  Google Scholar 

  18. Stouffer, D. B., Sales-Pardo, M., Sirer, M. I. & Bascompte, J. Evolutionary conservation of species’ roles in food webs. Science 335, 1489–1492 (2012).

    Article  CAS  PubMed  Google Scholar 

  19. Merritt, D. M., Scott, M. L., Poff, N. L., Auble, G. T. & Lytle, D. A. Theory, methods and tools for determining environmental flows for riparian vegetation: riparian vegetation-flow response guilds. Freshwater Biol. 55, 206–225 (2010).

    Article  Google Scholar 

  20. Milly, P. C. D., Dunne, K. A. & Vecchia, A. V. Global pattern of trends in streamflow and water availability in a changing climate. Nature 438, 347–350 (2005).

    Article  CAS  PubMed  Google Scholar 

  21. Gonzalez, A. & Loreau, M. The causes and consequences of compensatory dynamics in ecological communities. Annu. Rev. Ecol. Evol. Syst. 40, 393–414 (2009).

    Article  Google Scholar 

  22. Brown, B. L., Downing, A. L. & Leibold, M. A. Compensatory dynamics stabilize aggregate community properties in response to multiple types of perturbations. Ecology 97, 2021–2033 (2016).

    Article  PubMed  Google Scholar 

  23. Allesina, S. & Tang, S. Stability criteria for complex ecosystems. Nature 483, 205–208 (2012).

    Article  CAS  PubMed  Google Scholar 

  24. Mougi, A. et al. Diversity of interaction types and ecological community stability. Science 337, 349–351 (2012).

    Article  CAS  PubMed  Google Scholar 

  25. May, R. M. Will a large complex system be stable? Nature 238, 413–414 (1972).

    Article  CAS  PubMed  Google Scholar 

  26. Baiser, B., Russell, G. J. & Lockwood, J. L. Connectance determines invasion success via trophic interactions in model food webs. Oikos 119, 1970–1976 (2010).

    Article  Google Scholar 

  27. Aizen, M. A., Sabatino, M. & Tylianakis, J. M. Specialization and rarity predict nonrandom loss of interactions from mutualist networks. Science 335, 1486–1489 (2012).

    Article  CAS  PubMed  Google Scholar 

  28. Dai, A. Drought under global warming: a review. Rev. Clim. Change 2, 45–65 (2011).

    Google Scholar 

  29. Bunn, S. E. & Arthington, A. H. Basic principles and ecological consequences of altered flow regimes for aquatic biodiversity. Environ. Manage. 30, 492–507 (2002).

    Article  PubMed  Google Scholar 

  30. Rood, S. B., Goater, L. A., Mahoney, J. M., Pearce, C. M. & Smith, D. G. Floods, fire, and ice: disturbance ecology of riparian cottonwoods. Can. J. Bot. 85, 1019–1032 (2007).

    Article  Google Scholar 

  31. Olden, J. D. et al. Are large-scale flow experiments informing the science and management of freshwater ecosystems? Front. Ecol. Environ. 12, 176–185 (2014).

    Article  Google Scholar 

  32. Rood, S. B. et al. Declining summer flows of Rocky Mountain rivers: changing seasonal hydrology and probable impacts on floodplain forests. J. Hydrol. 349, 397–410 (2008).

    Article  Google Scholar 

  33. Stromberg, J. C. & Merritt, D. M. Riparian plant guilds of ephemeral, intermittent and perennial rivers. Freshwater Biol. 61, 1259–1275 (2016).

    Article  Google Scholar 

  34. Aguiar, F. C., Cerdeira, J. O., Martins, M. J. & Ferreira, M. T. Riparian forests of southwest Europe: are functional trait and species composition assemblages constrained by environment? J. Veg. Sci. 24, 628–638 (2013).

    Article  Google Scholar 

  35. Gurnell, A. M., Bertoldi, W. & Corenblit, D. Changing river channels: the roles of hydrological processes, plants and pioneer fluvial landforms in humid temperate, mixed load, gravel bed rivers. Earth Sci. Rev. 111, 129–141 (2012).

    Article  Google Scholar 

  36. Hupp, C. Hydrology, geomorphology and vegetation of coastal plain rivers in the south-eastern USA. Hydrol. Process. 14, 2991–3010 (2000).

    Article  Google Scholar 

  37. Lewinsohn, T. & Cagnolo, L. Keystones in a tangled bank. Science 335, 1449–1451 (2012).

    Article  CAS  PubMed  Google Scholar 

  38. Friedman, J. M. et al. Dominance of non-native riparian trees in western USA. Biol. Invasions 7, 747–751 (2005).

    Article  Google Scholar 

  39. Kominoski, J. S. et al. Forecasting functional implications of global changes in riparian plant communities. Front. Ecol. Environ. 11, 423–432 (2013).

    Article  Google Scholar 

  40. Rivaes, R. P. et al. Modeling the evolution of riparian woodlands facing climate change in three European rivers with contrasting flow regimes. PLoS ONE 9, e110200 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  41. Doody, T. M. et al. Quantifying water requirements of riparian river red gum (Eucalyptus camaldulensis) in the Murray-Darling Basin, Australia – implications for the management of environmental flows. Ecohydrology 8, 1471–1487 (2015).

    Article  Google Scholar 

  42. Kath, J., Le Brocque, A., Leyer, I. & Mosner, E. Hydrological and land use determinants of Eucalyptus camaldulensis occurrence in floodplain wetlands. Austral Ecol. 39, 643–655 (2014).

    Article  Google Scholar 

  43. Guilloy-Froget, H., Muller, E., Barsoum, N. & Hughes, F. M. R. Dispersal, germination, and survival of Populus nigra L. (Salicaceae) in changing hydrologic conditions. Wetlands 22, 478–488 (2002).

    Article  Google Scholar 

  44. Middleton, B. A. & Souter, N. J. Functional integrity of freshwater forested wetlands, hydrologic alteration, and climate change. Ecosyst. Health Sustain. 2, e01200 (2016).

    Article  Google Scholar 

  45. Andersen, D. C. & Cooper, D. J. Dams, floodplain land use, and riparian forest conservation in the semiarid Upper Colorado River Basin, USA. Environ. Manage. 40, 453–475 (2007).

    Article  PubMed  Google Scholar 

  46. Belmar, O., Bruno, D., Martínez-Capel, F., Barquín, J. & Velasco, J. Effects of flow regime alteration on fluvial habitats and riparian quality in a semiarid Mediterranean basin. Ecol. Indic. 30, 52–64 (2013).

    Article  Google Scholar 

  47. Tylianakis, J. M., Tscharntke, T. & Lewis, O. T. Habitat modification alters the structure of tropical host–parasitoid food webs. Nature 445, 202–205 (2007).

    Article  CAS  PubMed  Google Scholar 

  48. Merritt, D. M. & Bateman, H. L. Linking stream flow and groundwater to avian habitat in a desert riparian system. Ecol. Appl. 22, 1973–1988 (2012).

    Article  PubMed  Google Scholar 

  49. Shafroth, P. B., Auble, G. T., Stromberg, J. C. & Patten, D. T. Establishment of woody riparian vegetation in relation to annual patterns of streamflow, Bill Williams River, Arizona. Wetlands 18, 577–590 (1998).

    Article  Google Scholar 

  50. Lytle, D. A. & Merritt, D. M. Hydrologic regimes and riparian forests: a structured population model for cottonwood. Ecology 85, 2493–2503 (2004).

    Article  Google Scholar 

  51. R Core Team R: A Language and Environment for Statistical Computing (R Foundation for Statistical Computing, Vienna, 2015).

  52. Tonkin, J. D., Bogan, M. T., Bonada, N., Ríos-Touma, B. & Lytle, D. A. Seasonality and predictability shape temporal species diversity. Ecology 98, 1201–1216 (2017).

    Article  PubMed  Google Scholar 

  53. Novak, M. et al. Characterizing species interactions to understand press perturbations: what is the community matrix? Annu. Rev. Ecol. Evol. Syst. 47, 409–432 (2016).

    Article  Google Scholar 

  54. Csardi, G. & Nepusz, T. The igraph software package for complex network research. InterJournal, Complex Syst. 1695 (2006).

  55. Killick, R. & Eckley, I. A. Changepoint: an R package for changepoint analysis. J. Stat. Softw. 58, 1–19 (2014).

Download references

Acknowledgements

We thank N. L. Poff, A. Ruhi and members of the OSU Integrative Biology journal club for comments on earlier versions of the manuscript. Dinosaur National Monument and the US Bureau of Reclamation supported the research that led to the vital rate data. Funding was provided in part by the US Department of Defense (SERDP RC-2511) and the US Department of Agriculture Forest Service.

Author information

Authors and Affiliations

Authors

Contributions

J.D.T. and D.A.L. designed the study, developed the model and ran analyses; D.A.L. and D.M.M. compiled vital rate information; J.D.T. wrote the first draft of the manuscript in close collaboration with D.A.L., and all authors contributed substantially to writing in subsequent drafts.

Corresponding author

Correspondence to Jonathan D. Tonkin.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Electronic supplementary material

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Tonkin, J.D., Merritt, D.M., Olden, J.D. et al. Flow regime alteration degrades ecological networks in riparian ecosystems. Nat Ecol Evol 2, 86–93 (2018). https://doi.org/10.1038/s41559-017-0379-0

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41559-017-0379-0

This article is cited by

Search

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