Biological Invasions

, Volume 13, Issue 9, pp 2009–2022 | Cite as

Resource heterogeneity and persistence of exotic annuals in long-ungrazed Mediterranean-climate woodlands

Original Paper


Processes that promote weed invasion are often well-demonstrated, but mechanisms that facilitate ecological resistance to weed invasion in non-invaded communities, or promote weed persistence in invaded communities, are poorly understood. Yet it is these processes that must be addressed to achieve sustainable ecological restoration. We surveyed soil heterogeneity in 25 long-ungrazed, unfertilized York gum (Eucalyptus loxophleba Benth. subsp. loxophleba)—jam (Acacia acuminata Benth.) woodlands of the Western Australian wheatbelt to investigate differences in soil characteristics between patches locally-invaded or non-invaded by widespread exotic annuals. Based on studies in other ecosystems, we hypothesized that (1) weed persistence is associated with elevated soil resource levels, and (2) of these soil resources, phosphorus is the key contributor to weed persistence in Western Australian woodlands, that typically occur on phosphorus-impoverished soils. Our first hypothesis was partly supported, with soil nutrients associated with up to 40% of the variation in cover of exotic annuals. In particular, low concentrations of total nitrogen, nitrate and available phosphorus are likely to contribute to resistance to invasion in many non-invaded woodland patches, especially in gaps between trees. However, other non-invaded patches had comparable nutrient concentrations to invaded patches, suggesting this resistance may be weak at more productive sites or that patches have not reached a stable equilibrium. Inconsistent with our second hypothesis, exotic annuals were as strongly correlated with elevated total nitrogen and associated variables as they were with available phosphorus, probably reflecting a history of grazing without fertilization. We conclude that effectiveness of ‘bottom-up’ approaches to weed control is likely to differ among ecosystems according to interactions with disturbance history and attributes of the non-invaded community, even where the weed species or functional types are the same.


Ecological resistance Eucalypt woodlands Landuse legacy Nutrient enrichment 


  1. Adair EC, Burke IC, Lauenroth WK (2008) Contrasting effects of resource availability and plant mortality on plant community invasion by Bromus tectorum L. Plant Soil 304:103–115CrossRefGoogle Scholar
  2. Anand RR, Paine M (2002) Regolith geology of the Yilgarn Craton, Western Australia: implications for exploration. Aust J Earth Sci 49:3–162CrossRefGoogle Scholar
  3. Beard JS (1990) Plant life of Western Australia. Kangaroo Press, SydneyGoogle Scholar
  4. Belsky AJ, Mwonga SM, Amundson RG, Duxbury JM, Ali AR (1993) Comparative effects of isolated trees on their undercanopy environments in high- and low-rainfall savannas. J Appl Ecol 30:143–155CrossRefGoogle Scholar
  5. Binkley D, Sollins P (1990) Factors determining differences in soil pH in adjacent conifer and alder-conifer stands. Soil Sci Soc Am J 54:1427–1433CrossRefGoogle Scholar
  6. Blair GJ, Chinoim N, Lefroy RB, Anderson GC, Crocker GJ (1991) A soil sulfur test for pasture and crops. Aust J Soil Res 29:619–626CrossRefGoogle Scholar
  7. Blank B, Sforza R (2007) Plant-soil relationships of the invasive annual grass Taeniatherum caput-medusae: a reciprocal transplant experiment. Plant Soil 298:7–19CrossRefGoogle Scholar
  8. Booth MS, Caldwell MM, Stark JM (2003) Overlapping resource use in three Great Basin species: implications for community invasibility and vegetation dynamics. J Ecol 91:36–48CrossRefGoogle Scholar
  9. Briggs SV, Taws NM, Seddon JA, Vanzella B (2008) Condition of fenced and unfenced remnant vegetation in inland catchments in south-eastern Australia. Aust J Bot 56:590–599CrossRefGoogle Scholar
  10. Chambers JC, Roundy BA, Blank RR, Meyer SE, Whittaker A (2007) What makes Great Basin Sagebrush ecosystems invasible by Bromus tectorum? Ecol Monogr 77:117–145CrossRefGoogle Scholar
  11. Chilcott C, Reid NCH, King K (1997) Impact of trees on the diversity of pasture species and soil biota in grazed landscapes on the Northern Tablelands, NSW. In: Hale P, Lamb D (eds) Conservation outside nature reserves. University of Queensland, Brisbane, pp 378–386Google Scholar
  12. D’Antonio CM, Chambers JC (2006) Using ecological theory to manage or restore ecosystems affected by invasive plant species. In: Falk D, Palmer MA, Zedler J (eds) Foundations of restoration ecology. Island Press, WashingtonGoogle Scholar
  13. D’Antonio C, Meyerson LA (2002) Exotic plant species as problems and solutions in ecological restoration: a synthesis. Restor Ecol 10:703–713CrossRefGoogle Scholar
  14. Dukes JS (2001) Biodiversity and invasibility in grassland microcosms. Oecologia 126:563–568CrossRefGoogle Scholar
  15. Ehrenfeld G (2003) Effects of exotic plant invasions on soil nutrient cycling processes. Ecosystems 6:503–523CrossRefGoogle Scholar
  16. Fargione JE, Tilman D (2005) Diversity decreases invasion via both sampling and complementarity effects. Ecol Lett 8:604–611CrossRefGoogle Scholar
  17. Gaertner M, den Breeyen A, Hui C, Richardson DM (2009) Impacts of alien plant invasions on species richness in Mediterranean-type ecosystems: a meta-analysis. Prog Phys Geog 33:319–338CrossRefGoogle Scholar
  18. Greig-Smith P (1983) Quantitative plant ecology, 3rd edn. Blackwell, OxfordGoogle Scholar
  19. Groves RH, Di Castri F (1991) Biogeography of Mediterranean invasions. Cambridge University Press, CambridgeCrossRefGoogle Scholar
  20. Heady HF (1956) Changes in a California annual plant community induced by manipulation of natural mulch. Ecology 37:798–812CrossRefGoogle Scholar
  21. Hobbs RJ, Atkins L (1988) Effects of disturbance and nutrient addition on native and introduced annuals in plant communities in the Western Australian wheatbelt. Aust J Ecol 13:171–179CrossRefGoogle Scholar
  22. Hobbs RJ, Norton DA (1996) Towards a conceptual framework for restoration ecology. Restor Ecol 4:93–110CrossRefGoogle Scholar
  23. Houlder DH, Hutchinson MF, Nix HA, McMahon JP (2001) ANUCLIM user guide. Version 5.1. Centre for Resource and Environmental Studies. Australian National University, CanberraGoogle Scholar
  24. Huenneke LF, Hamburg SP, Koide R, Mooney HA, Vitousek PM (1990) Effects of soil resources on plant invasion and community structure in Californian serpentine grassland. Ecology 71:478–491CrossRefGoogle Scholar
  25. Jackson J, Ash AJ (2001) The role of trees in enhancing soil nutrient availability for native perennial grasses in open eucalypt woodlands of north-east Queensland. Aust J Agric Res 52:377–386CrossRefGoogle Scholar
  26. Keane RM, Crawley MJ (2002) Exotic plant invasions and the enemy release hypothesis. Trends Ecol Evol 17:164–170CrossRefGoogle Scholar
  27. Kellman M (1979) Soil enrichment by Neotropical savanna trees. J Ecol 67:565–577CrossRefGoogle Scholar
  28. Lambers H, Raven JA, Shaver GR, Smith SE (2008) Plant nutrient-acquisition strategies change with soil age. Trends Ecol Evol 23:95–103PubMedCrossRefGoogle Scholar
  29. Lenz TI, Facelli JM (2006) Correlations between environmental factors, the biomass of exotic annual grasses and the frequency of native perennial grasses. Aust J Bot 54:655–667CrossRefGoogle Scholar
  30. Lenz TI, Moyle-Croft JL, Facelli JM (2003) Direct and indirect effects of exotic annual grasses on species composition of a South Australian grassland. Austral Ecol 28:23–32CrossRefGoogle Scholar
  31. Main BY (1992) Social history and impact on landscape. In: Hobbs RJ, Saunders DA (eds) Reintegrating fragmented landscapes: towards sustainable production and nature conservation. Springer, New York, pp 23–58Google Scholar
  32. McCune B, Mefford MJ (1999) PC-ORD. Multivariate analysis of ecological data. Version 4. MjM Software Design, OregonGoogle Scholar
  33. McLendon T, Redente EF (1991) Nitrogen and phosphorus effects on secondary succession dynamics on a semi-arid sagebrush site. Ecology 72:2016–2024CrossRefGoogle Scholar
  34. Minchin PR (1989) DECODA user’s manual. Australian National University, CanberraGoogle Scholar
  35. Parker IM, Simberloff D, Lonsdale WM et al (1999) Impact: toward a framework for understanding the ecological effects of invaders. Biol Invasions 1:3–19CrossRefGoogle Scholar
  36. Perring MP, Edwards G, de Mazancourt C (2009) Removing phosphorus from ecosystems through nitrogen fertilization and cutting with removal of biomass. Ecosystems 12:1130–1144CrossRefGoogle Scholar
  37. Perry LG, Blumenthal DM, Monaco TA, Paschke MW, Redente EF (2010) Immobilizing nitrogen to control plant invasion. Oecologia 163:13–24PubMedCrossRefGoogle Scholar
  38. Pettit NE, Froend RH (2001) Long-term changes in the vegetation after the cessation of livestock grazing in Eucalyptus marginata (jarrah) woodland remnants. Austral Ecol 26:22–31CrossRefGoogle Scholar
  39. Pouliquen-Young O (1997) Evolution of the system of protected areas in Western Australia. Environ Conserv 24:168–181CrossRefGoogle Scholar
  40. Prober SM, Lunt I (2009) Restoration of Themeda australis swards suppresses soil nitrate and enhances ecological resistance to invasion by exotic annuals. Biol Invasions 11:171–181CrossRefGoogle Scholar
  41. Prober SM, Smith FP (2009) Enhancing biodiversity persistence in intensively-used agricultural landscapes: a synthesis of 30 years of research in the Western Australian wheatbelt. Agric Ecosyst Environ 132:173–191CrossRefGoogle Scholar
  42. Prober SM, Lunt I, Thiele KR (2002a) Determining reference conditions for management and restoration of temperate grassy woodlands: relationships among trees, topsoils and understorey flora in little-grazed remnants. Aust J Bot 50:687–697CrossRefGoogle Scholar
  43. Prober SM, Thiele KR, Lunt I (2002b) Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states. Aust J Bot 50:699–712CrossRefGoogle Scholar
  44. Prober SM, Thiele KR, Lunt I, Koen TB (2005) Restoring ecological function in temperate grassy woodlands - manipulating soil nutrients, annual exotics and native perennial grasses through carbon supplements and spring burns. J Appl Ecol 42:1073–1085CrossRefGoogle Scholar
  45. Prober SM, Lunt I, Morgan J (2009) Rapid internal plant-soil feedbacks lead to alternative stable states in temperate Australian grassy woodlands. In: Suding K, Hobbs RJ (eds) New models for ecosystem dynamics and restoration. Island Press, Washington, USA, pp 156–168Google Scholar
  46. Prober SM, Standish RJ, Wiehl G (2011) After the fence: vegetation and topsoil condition in grazed, fenced and benchmark eucalypt woodlands of fragmented agricultural landscapes. Aust J Bot 59. doi:10.1071/BT11026
  47. Rayment GE, Higginson FR (1992) Australian laboratory handbook of soil and water chemical methods. Inkata Press, MelbourneGoogle Scholar
  48. Scholes RJ, Archer SR (1997) Tree-grass interactions in savannas. Ann Rev Ecol Syst 28:517–544CrossRefGoogle Scholar
  49. Seabloom EW, Harpole WS, Reichman OJ, Tilman D (2003) Invasion, competitive dominance, and resource use by exotic and native Californian grassland species. Proc Natl Acad Sci USA 100:13384–13389PubMedCrossRefGoogle Scholar
  50. Searle PL (1984) The berthelot or indophenol reaction and its use in the analytical chemistry of nitrogen. A review. Analyst 109:549–568CrossRefGoogle Scholar
  51. Shepherd DP, Beeston GR, Hopkins AJM (2002) Native vegetation in Western Australia: extent, type and status. Department of Agriculture, Western Australia, PerthGoogle Scholar
  52. Shirato Y, Yokozawa M (2006)  Acid hydrolysis to partition plant material into decomposable and resistant fractions for use in the Rothamsted carbon model. Soil Biol Biochem 38:812–816CrossRefGoogle Scholar
  53. Smallbone L, Prober SM, Lunt ID (2007) Restoration treatments enhance early establishment of native forbs in a degraded grassy woodland. Aust J Bot 55:818–830CrossRefGoogle Scholar
  54. Specht RL (1963) Dark Island heath (Ninety-Mile Plain, South Australia) VII. The effect of fertilizers on composition and growth 1950–1960. Aust J Bot 11:67–94CrossRefGoogle Scholar
  55. Spooner PV, Briggs SV (2008) Woodlands on farms in southern NSW: a longer-term assessment of vegetation changes after fencing. Ecol Manage Restor 9:33–41CrossRefGoogle Scholar
  56. Standish RJ, Cramer VA, Hobbs RJ, Kobryn HT (2006) Legacy of land-use evident in soils of Western Australia’s wheatbelt. Plant Soil 280:189–207CrossRefGoogle Scholar
  57. Standish RJ, Cramer VA, Wild SL, Hobbs RJ (2007a) Seed dispersal and recruitment limitation are barriers to native recolonization of old-fields in Western Australia. J Appl Ecol 44:435–445CrossRefGoogle Scholar
  58. Standish RJ, Stokes BA, Tibbett M, Hobbs RJ (2007b) Seedling response to phosphate addition and inoculation with arbuscular mycorrhizas and the implications for old-field restoration in Western Australia. Environ Exp Bot 61:58–65CrossRefGoogle Scholar
  59. Standish RJ, Cramer VA, Hobbs RJ (2008) Land-use legacy and the persistence of invasive Avena barbata on abandoned farmland. J Appl Ecol 45:1576–1583CrossRefGoogle Scholar
  60. Thomsen MA, D’Antonio CM (2007) Mechanisms of resistance to invasion in a California grassland: the roles of competitor identity, resource availability, and environmental gradients. Oikos 116:17–30CrossRefGoogle Scholar
  61. Tongway D, Ludwig J (1990) Vegetation and soil patterning in semi-arid mulga lands of Eastern Australia. Aust J Ecol 15:23–34CrossRefGoogle Scholar
  62. Vlok JHJ (1988) Alpha diversity of lowland fynbos herbs at various levels of infestation by alien annuals. S Afr J Bot 54:623–627Google Scholar
  63. Wang F, Li Z, Xia H, Zou B, Li N, Liu J, Zhu W (2010) Effects of nitrogen-fixing and non-nitrogen-fixing tree species on soil properties and nitrogen transformation during forest restoration in southern China. Soil Sci Plant Nutr 56:297–306CrossRefGoogle Scholar
  64. Western Australian Herbarium (2011) FloraBase—the Western Australian Flora. Department of Environment and Conservation.
  65. Wilson SD, Partel M (2003) Extirpation or coexistence? Management of a persistent introduced grass in a prairie restoration. Restor Ecol 11:410–416CrossRefGoogle Scholar
  66. Witkowski ETF (1989) Response to nutrient additions by the plant growth forms of sand-plain lowland fynbos, South Africa. Vegetatio 79:89–97CrossRefGoogle Scholar

Copyright information

© CSIRO 2011

Authors and Affiliations

  1. 1.CSIRO Ecosystem SciencesWembleyAustralia

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