, Volume 165, Issue 3, pp 771–781 | Cite as

Increasing native, but not exotic, biodiversity increases aboveground productivity in ungrazed and intensely grazed grasslands

  • Forest I. Isbell
  • Brian J. Wilsey
Ecosystem ecology - Original Paper


Species-rich native grasslands are frequently converted to species-poor exotic grasslands or pastures; however, the consequences of these changes for ecosystem functioning remain unclear. Cattle grazing (ungrazed or intensely grazed once), plant species origin (native or exotic), and species richness (4-species mixture or monoculture) treatments were fully crossed and randomly assigned to plots of grassland plants. We tested whether (1) native and exotic plots exhibited different responses to grazing for six ecosystem functions (i.e., aboveground productivity, light interception, fine root biomass, tracer nitrogen uptake, biomass consumption, and aboveground biomass recovery), and (2) biodiversity–ecosystem functioning relationships depended on grazing or species origin. We found that native and exotic species exhibited different responses to grazing for three of the ecosystem functions we considered. Intense grazing decreased fine root biomass by 53% in exotic plots, but had no effect on fine root biomass in native plots. The proportion of standing biomass consumed by cattle was 16% less in exotic than in native grazed plots. Aboveground biomass recovery was 30% less in native than in exotic plots. Intense grazing decreased aboveground productivity by 25%, light interception by 14%, and tracer nitrogen uptake by 54%, and these effects were similar in native and exotic plots. Increasing species richness from one to four species increased aboveground productivity by 42%, and light interception by 44%, in both ungrazed and intensely grazed native plots. In contrast, increasing species richness did not influence biomass production or resource uptake in ungrazed or intensely grazed exotic plots. These results suggest that converting native grasslands to exotic grasslands or pastures changes ecosystem structure and processes, and the relationship between biodiversity and ecosystem functioning.


Land-use change Novel ecosystems Ecosystem functioning Root biomass Resilience 



We thank Dan Isbell, Steve Goepferd, Leah Isbell, Kathryn Yurkonis, Joe Reynolds, Chris Johnson, Cedar Johnson, Kim Isbell, Joni Richmond, Robert Handler, Leanne Martin, Adam Heathcote, Wayne Roush, and Don Hummel for help with field work. This project was supported by a grant from the US National Science Foundation (DEB-0639417) to B.J.W. and a grant from the Leopold Center for Sustainable Agriculture to B.J.W. and F.I.I. We thank Jason Kaye and anonymous reviewers for helpful comments on an earlier version of this manuscript.


  1. Asner GP, Elmore AJ, Olander LP, Martin RE, Harris AT (2004) Grazing systems, ecosystem responses, and global change. Annu Rev Environ Resour 29:261–299CrossRefGoogle Scholar
  2. Balvanera P et al (2006) Quantifying the evidence for biodiversity effects on ecosystem functioning and services. Ecol Lett 9:1146–1156CrossRefPubMedGoogle Scholar
  3. Best RJ, Arcese P (2009) Exotic herbivores directly facilitate the exotic grasses they graze: mechanisms for an unexpected positive feedback between invaders. Oecologia 159:139–150CrossRefPubMedGoogle Scholar
  4. Buchmann N, Gebauer G, Schulze ED (1996) Partitioning of 15N-labeled ammonium and nitrate among soil, litter, below- and above-ground biomass of trees and understory in a 15-year-old Picea abies plantation. Biogeochemistry 33:1–23CrossRefGoogle Scholar
  5. Byrnes J, Stachowicz JJ (2009) Short and long term consequences of increases in exotic species richness on water filtration by marine invertebrates. Ecol Lett 12:830–841CrossRefPubMedGoogle Scholar
  6. Cardinale BJ et al (2006) Effects of biodiversity on the functioning of trophic groups and ecosystems. Nature 443:989–992CrossRefPubMedGoogle Scholar
  7. Chaneton EJ, Perelman SB, Omacini M, Leon RJC (2002) Grazing, environmental heterogeneity, and alien plant invasions in temperate Pampa grasslands. Biol Invasions 4:7–24CrossRefGoogle Scholar
  8. Coley PD, Bryant JP, Chapin FS (1985) Resource availability and plant antiherbivore defense. Science 230:895–899CrossRefPubMedGoogle Scholar
  9. D’Antonio CM, Vitousek PM (1992) Biological invasions by exotic grasses, the grass fire cycle, and global change. Annu Rev Ecol Syst 23:63–87Google Scholar
  10. Daehler CC (2003) Performance comparisons of co-occurring native and alien invasive plants: implications for conservation and restoration. Annu Rev Ecol Evol Syst 34:183–211CrossRefGoogle Scholar
  11. Dybzinski R, Tilman D (2007) Resource use patterns predict long-term outcomes of plant competition for nutrients and light. Am Nat 170:305–318CrossRefPubMedGoogle Scholar
  12. Fry B (2006) Stable isotope ecology. Springer, New YorkCrossRefGoogle Scholar
  13. Hautier Y, Niklaus PA, Hector A (2009) Competition for light causes plant biodiversity loss after eutrophication. Science 324:636–638CrossRefPubMedGoogle Scholar
  14. Hector A, Hooper R (2002) Darwin and the first ecological experiment. Science 295:639–640CrossRefPubMedGoogle Scholar
  15. Hobbs RJ et al (2006) Novel ecosystems: theoretical and management aspects of the new ecological world order. Glob Ecol Biogeogr 15:1–7CrossRefGoogle Scholar
  16. Hooper DU et al (2005) Effects of biodiversity on ecosystem functioning: a consensus of current knowledge. Ecol Monogr 75:3–35CrossRefGoogle Scholar
  17. Isbell FI (2010) Processes that influence biodiversity, ecosystem functioning, and stability in grasslands. PhD dissertation, Iowa State University, AmesGoogle Scholar
  18. Isbell FI, Polley HW, Wilsey BJ (2009) Species interaction mechanisms maintain grassland plant diversity. Ecology 90:1821–1830CrossRefPubMedGoogle Scholar
  19. Keeley JE, Lubin D, Fotheringham CJ (2003) Fire and grazing impacts on plant diversity and alien plant invasions in the southern Sierra Nevada. Ecol Appl 13:1355–1374CrossRefGoogle Scholar
  20. Kimball S, Schiffman PM (2003) Differing effects of cattle grazing on native and alien plants. Conserv Biol 17:1681–1693CrossRefGoogle Scholar
  21. Levy EG, Madden EA (1933) The point method of pasture analysis. N Z J Agric 46:267–279Google Scholar
  22. Liao CZ et al (2008) Altered ecosystem carbon and nitrogen cycles by plant invasion: a meta-analysis. New Phytol 177:706–714CrossRefPubMedGoogle Scholar
  23. Loreau M, Hector A (2001) Partitioning selection and complementarity in biodiversity experiments. Nature 412:72–76CrossRefPubMedGoogle Scholar
  24. Losure DA, Wilsey BJ, Moloney KA (2007) Evenness-invasibility relationships differ between two extinction scenarios in tallgrass prairie. Oikos 116:87–98CrossRefGoogle Scholar
  25. McNaughton SJ (1979) Grazing as an optimization process: grass-ungulate relationships in the Serengeti. Am Nat 113:691–703CrossRefGoogle Scholar
  26. McNaughton SJ (1985) Ecology of a grazing ecosystem: the Serengeti. Ecol Monogr 55:259–294CrossRefGoogle Scholar
  27. McNaughton SJ (1993a) Biodiversity and ecosystem function of grazing ecosystems. In: Schulze ED, Mooney HA (eds) Biodiversity and ecosystem function. Springer, Berlin, pp 361–383Google Scholar
  28. McNaughton SJ (1993b) Grasses and grazers, science and management. Ecol Appl 3:17–20CrossRefGoogle Scholar
  29. McNaughton SJ, Oesterheld M, Frank DA, Williams KJ (1989) Ecosystem-level patterns of primary productivity and herbivory in terrestrial habitats. Nature 341:142–144CrossRefPubMedGoogle Scholar
  30. Milchunas DG, Lauenroth WK (1993) Quantitative effects of grazing on vegetation and soils over a global range of environments. Ecol Monogr 63:327–366CrossRefGoogle Scholar
  31. Minns A et al (2001) The functioning of European grassland ecosystems: potential benefits of biodiversity to agriculture. Outlook Agric 30:179–185CrossRefGoogle Scholar
  32. Painter EL, Belsky AJ (1993) Application of herbivore optimization theory to rangelands of the western United States. Ecol Appl 3:2–9CrossRefGoogle Scholar
  33. Peterson BJ, Fry B (1987) Stable isotopes in ecosystem studies. Annu Rev Ecol Syst 18:293–320CrossRefGoogle Scholar
  34. Picasso VD, Brummer EC, Liebman M, Dixon PM, Wilsey BJ (2008) Crop species diversity affects productivity and weed suppression in perennial polycultures under two management strategies. Crop Sci 48:331–342CrossRefGoogle Scholar
  35. Proulx M, Mazumder A (1998) Reversal of grazing impact on plant species richness in nutrient-poor vs. nutrient-rich ecosystems. Ecology 79:2581–2592CrossRefGoogle Scholar
  36. Reich PB et al (2001) Plant diversity enhances ecosystem responses to elevated CO2 and nitrogen deposition. Nature 410:809–812CrossRefPubMedGoogle Scholar
  37. Sanderson MA, Skinner RH, Barker DJ, Edwards GR, Tracy BF, Wedin DA (2004) Plant species diversity and management of temperate forage and grazing land ecosystems. Crop Sci 44:1132–1144CrossRefGoogle Scholar
  38. Schmid B, Hector A, Saha P, Loreau M (2008) Biodiversity effects and transgressive overyielding. J Plant Ecol 1:95–102CrossRefGoogle Scholar
  39. Seastedt TR, Hobbs RJ, Suding KN (2008) Management of novel ecosystems: are novel approaches required? Front Ecol Environ 6:547–553CrossRefGoogle Scholar
  40. Simoes M, Baruch Z (1991) Responses to simulated herbivory and water-stress in two tropical C4 grasses. Oecologia 88:173–180CrossRefGoogle Scholar
  41. Smith MD, Knapp AK (2001) Physiological and morphological traits of exotic, invasive exotic, and native plant species in tallgrass prairie. Int J Plant Sci 162:785–792CrossRefGoogle Scholar
  42. Vila M, Weiner J (2004) Are invasive plant species better competitors than native plant species? Evidence from pair-wise experiments. Oikos 105:229–238CrossRefGoogle Scholar
  43. Wassenaar T, Gerber P, Verburg PH, Rosales M, Ibrahim M, Steinfeld H (2007) Projecting land use changes in the Neotropics: the geography of pasture expansion into forest. Glob Environ Change Hum Policy Dimens 17:86–104Google Scholar
  44. Weigelt A, Weisser WW, Buchmann N, Scherer-Lorenzen M (2009) Biodiversity for multifunctional grasslands: equal productivity in high-diversity low-input and low-diversity high-input systems. Biogeosciences 6:1695–1706CrossRefGoogle Scholar
  45. Wilsey BJ (2005) Importance of species replication in understanding plant invasions into North American grasslands. In: Inderjit S (ed) Invasive plants: ecological and agricultural aspects. Birkhauser, SwitzerlandGoogle Scholar
  46. Wilsey BJ, Polley HW (2006) Aboveground productivity and root-shoot allocation differ between native and introduced grass species. Oecologia 150:300–309CrossRefPubMedGoogle Scholar
  47. Wilsey BJ, Coleman JS, McNaughton SJ (1997) Effects of elevated CO2 and defoliation on grasses: a comparative ecosystem approach. Ecol Appl 7:844–853Google Scholar
  48. Wilsey BJ, Teaschner TB, Daneshgar PP, Isbell FI, Polley HW (2009) Biodiversity maintenance mechanisms differ between native and novel exotic-dominated communities. Ecol Lett 12:432–442CrossRefPubMedGoogle Scholar
  49. Worm B et al (2006) Impacts of biodiversity loss on ocean ecosystem services. Science 314:787–790CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.Department of Ecology, Evolution, and Organismal BiologyIowa State UniversityAmesUSA
  2. 2.Department of BiologyMcGill UniversityMontrealCanada

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