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Biodiversity and Conservation

, Volume 18, Issue 9, pp 2327–2342 | Cite as

Plant community response to loss of large herbivores: comparing consequences in a South African and a North American grassland

  • Catherine E. BurnsEmail author
  • Scott L. Collins
  • Melinda D. Smith
Original Paper

Abstract

Loss of biodiversity poses one of the greatest threats to natural ecosystems throughout the world. However, a comprehensive understanding of the impacts of species losses from upper trophic levels is still emerging. Here we compare the impacts of large mammalian herbivore species loss on grassland plant community structure and composition in a South African and North American grassland. Herbaceous plant communities were surveyed at sites without large mammalian herbivores present and at sites with a single species of herbivore present in both locations, and additionally at one site in South Africa with multiple herbivore species. At both the North American and South African locations, plant communities on sites with a single herbivore species were more diverse and species rich than on sites with no herbivores. At the multi-herbivore site in South Africa, plant diversity and richness were comparable to that of the single herbivore site early in the growing season and to the no herbivore site late in the growing season. Analyses of plant community composition, however, indicated strong differences between the multi-herbivore site and the single and no herbivore sites, which were more similar to each other. In moderate to high-productivity ecosystems with one or a few species of large herbivores, loss of herbivores can cause a significant decrease in plant diversity and richness, and can have pronounced impacts on grassland plant community composition. In ecosystems with higher herbivore richness, species loss may also significantly alter plant community structure and composition, although standard metrics of community structure may obscure these differences.

Keywords

Biodiversity Community structure Diversity Herbivory Richness Savanna Species loss 

Notes

Acknowledgments

Many thanks to the staff of Kruger National Park—most notably H Biggs, D Pienaar, A Potgieter, N Zambatis, and N Govender—for their support of this research and for their faithful maintenance of the Experimental Burn Plots in the Satara region of the park. Thanks also to the staff of the Konza Prairie Biological Station for their support of this research. J Bowers, G Buis and M Kruger provided supplementary information useful in establishing the characteristics and history of each study location. L Calabrese, R Fynn, J Heisler, A Knapp, J Nippert, L Zeglin, and A Zinn assisted in the data collection. G Overbeck, R Fynn and two anonymous reviewers provided helpful feedback during manuscript preparation. This research was supported by National Science Foundation grants DEB-0516145 to MDS and DEB-0516155 to SLC. C Burns was supported in part by a Brown Postdoctoral Research Fellowship at Yale University.

References

  1. Anderson TM, Ritchie ME, McNaughton SJ (2007) Rainfall and soils modify plant community response to grazing in Serengeti National Park. Ecology 88:1191–1201. doi: 10.1890/06-0399 PubMedCrossRefGoogle Scholar
  2. Augustine DJ, McNaughton SJ (2004) Regulation of shrub dynamics by native browsing ungulates on East African rangeland. J Appl Ecol 41:45–58. doi: 10.1111/j.1365-2664.2004.00864.x CrossRefGoogle Scholar
  3. Bakker ES, Ritchie ME, Olff H, Milchunas DG, Knops JMH (2006) Herbivore impact on grassland plant diversity depends on habitat productivity and herbivore size. Ecol Lett 9:780–788. doi: 10.1111/j.1461-0248.2006.00925.x PubMedCrossRefGoogle Scholar
  4. Barkley TM (1986) Flora of the Great Plains. University Press of Kansas, University of Kansas, Lawrence, KansasGoogle Scholar
  5. Biggs R, Biggs HC, Dunne TT, Govender N, Potgieter ALF (2003) Experimental burn plot trial in the Kruger National Park: history, experimental design and suggestions for data analysis. Koedoe 46:1–15Google Scholar
  6. Bond WJ, Midgley GF, Woodward FI (2003) What controls South African vegetation—climate or fire? S Afr J Bot 69:79–91Google Scholar
  7. Briggs JM, Knapp AK (1995) Interannual variability in primary production in tallgrass prairie: climate, soil moisture, topographic position and fire as determinants of aboveground biomass. Am J Bot 82:1024–1030. doi: 10.2307/2446232 CrossRefGoogle Scholar
  8. Brown BJ, Allen TFH (1989) The importance of scale in evaluating herbivory impacts. Oikos 54:189–195. doi: 10.2307/3565265 CrossRefGoogle Scholar
  9. Clarke KR, Gorley RN (2001) PRIMER v5: user manual/tutorial. PRIMER-E, Plymouth, UKGoogle Scholar
  10. Collins SL (1987) Interaction of disturbances in tallgrass prairie: a field experiment. Ecology 68:1243–1250. doi: 10.2307/1939208 CrossRefGoogle Scholar
  11. Collins SL, Smith MD (2006) Scale-dependent interaction of fire and grazing on community heterogeneity in tallgrass prairie. Ecology 87:2058–2067. doi: 10.1890/0012-9658(2006)87[2058:SIOFAG]2.0.CO;2 PubMedCrossRefGoogle Scholar
  12. Collins SL, Wallace LL (1990) Fire in North American tallgrass prairies. University of Oklahoma Press, Norman, OklahomaGoogle Scholar
  13. Collins SL, Knapp AK, Briggs JM, Blair JM, Steinauer EM (1998) Modulation of diversity by grazing and mowing in native tallgrass prairie. Science 280:745–747. doi: 10.1126/science.280.5364.745 PubMedCrossRefGoogle Scholar
  14. del Pozo A, Ovalle C, Casado MA, Acosta B, de Miguel JM (2006) Effects of grazing intensity in grasslands of the Espinal of central Chile. J Veg Sci 17:791–798. doi: 10.1658/1100-9233(2006)17[791:EOGIIG]2.0.CO;2 CrossRefGoogle Scholar
  15. Dorrough JW, Ash JE, Bruce S, McIntyre S (2007) From plant neighbourhood to landscape scales: how grazing modifies native and exotic plant species richness in grassland. Plant Ecol 191:185–198. doi: 10.1007/s11258-006-9236-y CrossRefGoogle Scholar
  16. du Toit JT (2003) Large herbivores and savanna heterogeneity. In: du Toit JT, Rogers KH, Biggs HC (eds) The Kruger experience: ecology and management of savanna heterogeneity. Island Press, Washington, pp 292–309Google Scholar
  17. du Toit JT, Cumming DHM (1999) Functional significance of ungulate diversity in African savannas and the ecological implications of the spread of pastoralism. Biodivers Conserv 8:1643–1661CrossRefGoogle Scholar
  18. du Toit JT, Rogers KH, Biggs HC (2003) The Kruger experience, ecology and management of Savanna heterogeneity. Island Press, WashingtonGoogle Scholar
  19. Duffy JE (2002) Biodiversity and ecosystem function: the consumer connection. Oikos 99:201–219. doi: 10.1034/j.1600-0706.2002.990201.x CrossRefGoogle Scholar
  20. Eckhardt HC, van Wilgen BW, Biggs HC (2000) Trends in woody vegetation cover in the Kruger National Park, South Africa, between 1940 and 1998. Afr J Ecol 38:108–115CrossRefGoogle Scholar
  21. Enslin BW, Potgieter ALF, Biggs HC, Biggs R (2000) Long term effects of fire frequency and season on the woody vegetation dynamics of the Sclerocarya birrea/Acacia nigrescens savanna of the Kruger National Park. Koedoe 43:27–37Google Scholar
  22. Frank DA (2005) The interactive effects of grazing ungulates and aboveground production on grassland diversity. Oecologia 143:629–634PubMedCrossRefGoogle Scholar
  23. Frank DA, McNaughton SJ, Tracy BF (1998) The ecology of the Earth’s grazing ecosystems. Bioscience 48:513–521CrossRefGoogle Scholar
  24. Fuhlendorf SD, Harrell WC, Engle DM, Hamilton RG, Davis CA, Leslie DM (2006) Should heterogeneity be the basis for conservation? Grassland bird response to fire and grazing. Ecol Appl 16:1706–1716PubMedCrossRefGoogle Scholar
  25. Govender N, Trollope WSW, van Wilgen BW (2006) The effect of fire season, fire frequency, rainfall and management on fire intensity in savanna vegetation in South Africa. J Appl Ecol 43:748–758CrossRefGoogle Scholar
  26. Harrison S, Inouye BD, Safford HD (2003) Ecological heterogeneity in the effects of grazing and fire on grassland diversity. Conserv Biol 17:837–845CrossRefGoogle Scholar
  27. Hartnett DC, Hickman KR, Walter LEF (1996) Effects of bison grazing, fire and topography on floristic diversity in tallgrass prairie. J Range Manag 49:413–420CrossRefGoogle Scholar
  28. Heisler JL, Briggs JM, Knapp AK (2003) Long-term patterns of shrub expansion in a C-4-dominated grassland: fire frequency and the dynamics of shrub cover and abundance. Am J Bot 90:423–428CrossRefGoogle Scholar
  29. Hickman KR, Hartnett DC, Cochran RC, Owensby CE (2004) Grazing management effects on plant species diversity in tallgrass prairie. J Range Manag 57:58–65CrossRefGoogle Scholar
  30. Hobbs NT (1996) Modification of ecosystems by ungulates. J Wildl Manage 60:695–713CrossRefGoogle Scholar
  31. Hooper DU, Chapin FS, Ewel JJ, Hector A, Inchausti P, Lavorel S, Lawton JH, Lodge DM, Loreau M, Naeem S, Schmid B, Setala H, Symstad AJ, Vandermeer J, Wardle DA (2005) Effects of biodiversity on ecosystem functioning: a consensus of current knowledge. Ecol Monogr 75:3–35CrossRefGoogle Scholar
  32. Jacobs SM, Naiman RJ (2008) Large African herbivores decrease herbaceous plant biomass while increasing plant species richness in a semi-arid savanna toposequence. J Arid Environ 72:891–903CrossRefGoogle Scholar
  33. Jacobs BF, Kingston JD, Jacobs LL (1999) The origin of grass-dominated ecosystems. Ann Mo Bot Gard 86:590–643CrossRefGoogle Scholar
  34. Joern A (2005) Disturbance by fire frequency and bison grazing modulate grasshopper assemblages in tallgrass prairie. Ecology 86:861–873CrossRefGoogle Scholar
  35. Knapp AK, Briggs JM, Hartnett DC, Collins SL (1998) Grassland dynamics: long-term ecological research in tallgrass prairie. Oxford University Press, New York, USAGoogle Scholar
  36. Knapp AK, Blair JM, Briggs JM, Collins SL, Hartnett DC, Johnson LC, Towne EG (1999) The keystone role of bison in North American tallgrass prairie. Bioscience 49:39–50CrossRefGoogle Scholar
  37. Knapp AK, Smith MD, Collins SL, Zambatis N, Peel M, Emery S, Wojdak J, Horner-Devine MC, Biggs H, Kruger J, Andelman SJ (2004) Generality in ecology: testing North American grassland rules in South African savannas. Front Ecol Environ 2:483–491CrossRefGoogle Scholar
  38. Knapp AK, Burns CE, Fynn R, Kirkman K, Morris C, Smith MD (2006) Convergence and contingency in production–precipitation relationships in North American and South African C4 savanna grasslands. Oecologia 149:456–464PubMedCrossRefGoogle Scholar
  39. Loreau M, Naeem S, Inchasti P (2002) Biodiversity and ecosystem functioning: synthesis and perspectives. Oxford University Press, Oxford, UKGoogle Scholar
  40. Magurran AE (1988) Ecological diversity and its measurement. Princeton University Press, Princeton, New JerseyGoogle Scholar
  41. Martens JC, Danckwerts JE, Zacharias PJK (1996) Species responses to grazing in the Smaldeel area of the Eastern Cape. Afr J Range Forage Sci 13:29–36Google Scholar
  42. Martin PS (1984) Prehistoric overkill: the global model. In: Martin PS, Klein RG (eds) Quaternary extinctions: a prehistoric revolution. University of Arizona Press, Tucson, Arizona, pp 354–403Google Scholar
  43. 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
  44. Milchunas DG, Sala OE, Lauenroth WK (1988) A generalized-model of the effects of grazing by large herbivores on grassland community structure. Am Nat 132:87–106CrossRefGoogle Scholar
  45. Noy-Meir I (1995) Interactive effects of fire and grazing on structure and diversity of Mediterranean grasslands. J Veg Sci 6:701–710CrossRefGoogle Scholar
  46. Olff H, Ritchie ME (1998) Effects of herbivores on grassland plant diversity. Trends Ecol Evol 13:261–265CrossRefGoogle Scholar
  47. Palmer TM, Stanton ML, Young TP, Goheen JR, Pringle RM, Karban R (2008) Breakdown of an ant–plant mutualism follows the loss of large herbivores from an African Savanna. Science 319:192–195PubMedCrossRefGoogle Scholar
  48. Pimm SL, Russell GJ, Gittleman JL, Brooks TM (1995) The future of biodiversity. Science 269:347–350PubMedCrossRefGoogle Scholar
  49. 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
  50. Pykala J (2003) Effects of restoration with cattle grazing on plant species composition and richness of semi-natural grasslands. Biodivers Conserv 12:2211–2226CrossRefGoogle Scholar
  51. Ransom MD, Rice CW, Todd TC, Wehmueller WA (1998) Soils and soil biota. In: Knapp AK, Briggs JM, Hartnett DC, Collins SL (eds) Grassland dynamics: long-term ecological research in tallgrass prairie. Oxford University Press, New York, pp 48–66Google Scholar
  52. Scholes RJ, Bond WJ, Eckhardt HC (2003a) Vegetation dynamics in the Kruger ecosystem. In: du Toit JT, Rogers KH, HC Biggs (eds) The Kruger experience: ecology and management of savanna heterogeneity. Island Press, Washington, pp 242–262Google Scholar
  53. Scholes MC, Scholes RJ, Otter LB, Woghiren AJ (2003b) Biogeochemistry: the cycling of elements. In: du Toit JT, Rogers KH, Biggs HC (eds) The Kruger experience: ecology and management of savanna heterogeneity. Island Press, Washington, pp 130–148Google Scholar
  54. Snyman HA (2000) Quantification of the soil–water balance under different veld condition classes in a semi-arid climate. Afr J Range Forage Sci 16:108–117Google Scholar
  55. Snyman HA (2002) Short-term response of rangeland botanical composition and productivity to fertilization (N and P) in a semi-arid climate of South Africa. J Arid Environ 50:167–183CrossRefGoogle Scholar
  56. Stohlgren TJ, Schell LD, Vanden Heuvel B (1999) How grazing and soil quality affect native and exotic plant diversity in rocky mountain grasslands. Ecol Appl 9:45–64CrossRefGoogle Scholar
  57. Tilman D, Reich PB, Knops J, Wedin D, Mielke T, Lehman C (2001) Diversity and productivity in a long-term grassland experiment. Science 294:843–845PubMedCrossRefGoogle Scholar
  58. Trager MD, Wilson GWT, Hartnett DC (2004) Concurrent effects of fire regime, grazing and bison wallowing on tallgrass prairie vegetation. Am Midl Nat 152:237–247CrossRefGoogle Scholar
  59. Trollope WSW, Potgieter ALF, Zambatis N (1989) Assessing veld condition in the Kruger National Park using key grass species. Koedoe 32:67–93Google Scholar
  60. Van Oudtshoorn F (1999) Guide to grasses of southern Africa. Briza Publications, Pretoria, South AfricaGoogle Scholar
  61. Venter FJ, Scholes RJ, Eckhardt HC (2003) The abiotic template and its associated vegetation pattern. In: du Toit JT, Rogers KH, Biggs HC (eds) The Kruger experience: ecology and management of savanna heterogeneity. Island Press, Washington, pp 83–129Google Scholar
  62. WallisDeVries MF, Bakker JP, Van Wieren SE (1998) Grazing and conservation management. Kluwer Academic Publishers, Dordrecht, The NetherlandsGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • Catherine E. Burns
    • 1
    • 2
    Email author
  • Scott L. Collins
    • 3
  • Melinda D. Smith
    • 1
  1. 1.Department of Ecology & Evolutionary BiologyYale UniversityNew HavenUSA
  2. 2.Department of Wildlife EcologyUniversity of MaineOronoUSA
  3. 3.Department of Biology, MSC03-2020University of New MexicoAlbuquerqueUSA

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