Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Naturalization of plant populations: the role of cultivation and population size and density


Field experimentation is required to assess the effects of environmental stochasticity on small immigrant plant populations—a widely understood but largely unexplored aspect of predicting any species’ likelihood of naturalization and potential invasion. Cultivation can mitigate this stochasticity, although the outcome for a population under cultivation nevertheless varies enormously from extinction to persistence. Using factorial experiments, we investigated the effects of population size, density, and cultivation (irrigation) on the fate of founder populations for four alien species with different life history characteristics (Echinochloa frumentacea, Fagopyrum esculentum, Helianthus annuus, and Trifolium incarnatum) in eastern Washington, USA. The fate of founder populations was highly variable within and among the 3 years of experimentation and illustrates the often precarious environment encountered by plant immigrants. Larger founder populations produced more seeds (P < 0.001); the role of founder population size, however, differed among years. Irrigation resulted in higher percent survival (P < 0.001) and correspondingly larger net reproductive rate (R 0; P < 0.001). But the minimum level of irrigation for establishment, R 0 > 1, differed among years and species. Sowing density did not affect the likelihood of establishment for any species. Our results underscore the importance of environmental stochasticity in determining the fate of founder populations and the potential of cultivation and large population size in countering the long odds against naturalization. Any implementation of often proposed post-immigration field trials to assess the risk of an alien species becoming naturalized, a requisite step toward invasion, will need to assess different sizes of founder populations and the extent and character of cultivation (intentional or unintentional) that the immigrants might receive.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2a, b
Fig. 3
Fig. 4a–c
Fig. 5


  1. Bannister MH (1965) Variation in the breeding system of Pinus radiata. In: Baker HG, Stebbins GL (eds) The genetics of colonizing species. Academic Press, New York, pp 353–372

  2. Burke MJW, Grime JP (1996) An experimental study of plant community invasibility. Ecology 77:776–790

  3. Caswell H (1989) Matrix population models. Sinauer, Sunderland

  4. Crawley MJ (1989) Chance and timing in biological invasions. In: Drake JA, Mooney HA, di Castri F, Groves RH, Kruger FJ, Rejmanek M, Williamson M (eds) Biological invasions. A global perspective. Wiley, Chichester, pp 407–423

  5. Crawley MJ, Hails RS, Rees M, Kohn D, Buxton J (1993) Ecology of transgenic oilseed rape in natural habitats. Nature 363:620–623

  6. Daubenmire R (1970) Steppe vegetation of Washington. Wash Agric Exp Stn Tech Bull 62

  7. Davis AS, Cousens RD, Hill J, Mack RN, Simberloff D, Raghu S (2010) Screening bioenergy feedstock crops to mitigate invasion risk. Front Ecol Environ. doi:10.1890/090030

  8. FAO (1996) International standards for phytosanitary measures, import regulations: guidelines for risk analysis. Secretariat of the International Plant Convention of the Food and Agriculture Organization (FAO) of the United Nations, Rome

  9. FAO (2001) International standards for phytosanitary measures: guidelines for phytosanitary certificates. Secretariat of the International Plant Convention of the Food and Agriculture Organization (FAO) of the United Nations, Rome

  10. Grevstad FS (1999a) Experimental invasions using biological control introductions: the influence of release size on the chance of population establishment. Biol Invasions 1:313–323

  11. Grevstad FS (1999b) Factors influencing the chance of population establishment: implications for release strategies in biocontrol. Ecol Appl 9:1439–1447

  12. Guerrant EO (1996) Designing populations: demographic, genetic, and horticultural dimensions. In: Falk DA, Millar CI, Olwell M (eds) Restoring diversity: strategies for reintroduction of endangered plants. Island Press, Washington, DC, pp 171–207

  13. Harper JL (1977) Population biology of plants. Academic Press, London

  14. Higgins SI, Pickett STA, Bond WJ (2000) Predicting extinction risks for plants: environmental stochasticity can save declining populations. Trends Ecol Evol 15:516–520

  15. Hitchcock CL, Cronquist A (1996) Flora of the Pacific Northwest. University of Washington Press, Seattle

  16. Hobbs RJ, Mooney HA (1991) Effects of rainfall variability and gopher disturbance on serpentine annual grassland dynamics. Ecology 72:59–68

  17. Holm LG, Plucknett DL, Pancho JV, Herberger JP (1977) The world’s worst weeds. University of Hawaii, Honolulu

  18. Jefferson L, Havens K, Ault J (2004) Implementing invasive screening procedures: the Chicago Botanic Garden model. Weed Technol 18:1434–1440

  19. Knapp AK, Fay PA, Blair JM et al (2002) Rainfall variability, carbon cycling, and plant species diversity in a mesic grassland. Science 298:2202–2205

  20. Knight WE (1985) Crimson clover. In: Taylor NL (ed) Clover science and technology. American Society of Agronomy, Madison, pp 491–502

  21. Knight RR, Eberhardt LL (1985) Population dynamics of Yellowstone grizzly bears. Ecology 66:323–334

  22. Kolar CS, Lodge DM (2001) Progress in invasion biology: predicting invaders. Trends Ecol Evol 16:199–204

  23. Lande R (1988) Genetics and demography in biological conservation. Science 241:1455–1460

  24. Lande R (1993) Risks of population extinction from demographic and environmental stochasticity and random catastrophes. Am Nat 142:911–927

  25. Lande R, Orzack SH (1988) Extinction dynamics of age-structured populations in a fluctuating environment. Proc Natl Acad Sci USA 85:7418–7421

  26. Lichter J (2000) Colonization constraints during primary succession on coastal Lake Michigan sand dunes. J Ecol 88:825–839

  27. Lockwood JL, Cassey P, Blackburn T (2005) The role of propagule pressure in explaining species invasions. Trends Ecol Evol 20:223–228

  28. Lonsdale WM (1994) Inviting trouble: introduced pasture species in northern Australia. Aust J Ecol 19:345–354

  29. Mack RN (1995) Understanding the processes of weed invasions: the influence of environmental stochasticity. In: Stirton CH (ed) Weeds in a changing world. British Crop Protection Council, symposium proceedings no. 64. Brighton, UK, pp 65–74

  30. Mack RN (2000) Cultivation fosters plant naturalization by reducing environmental stochasticity. Biol Invasions 2:111–122

  31. Mack RN (2005) Predicting the identity of plant invaders: future contributions from horticulture. HortScience 40:1168–1174

  32. Mack RN, Erneberg M (2002) The United States naturalized flora: largely the product of deliberate introductions. Ann Mo Bot Gard 89:176–189

  33. Maron JL (2006) The relative importance of latitude matching and propagule pressure in the colonization success of an invasive forb. Ecography 29:819–826

  34. Maun MA, Barrett SCH (1986) The biology of Canadian weeds. 77. Echinochloa crus-galli (L.) Beauv. Can J Plant Sci 66:739–759

  35. Menges ES (1991) The application of minimum viable population theory to plants. In: Falk DA, Holsinger KE (eds) Genetics and conservation of rare plants. Oxford University Press, New York, pp 45–61

  36. Menges ES (1992) Stochastic modeling of extinction in plant populations. In: Fiedler PL, Jain SK (eds) Conservation biology: the theory and practice of nature conservation preservation and management. Chapman and Hall, New York, pp 255–275

  37. Mollison D (1986) Modelling biological invasions: chance, explanation, prediction. Philos Trans R Soc Lond B Biol Sci 314:675–693

  38. Myers RL (1983) Site susceptibility to invasion by the exotic tree Melaleuca quinquenervia in southern Florida. J Appl Ecol 20:645–658

  39. National Oceanic and Atmospheric Administration (2003) Annual climatological summary. U.S. Department of Commerce, National Climatic Data Center, Asheville

  40. National Research Council (2002) Predicting invasions of nonindigenous plants and plant pests. National Academy Press, Washington, DC

  41. Page NA, Wall RE, Darbyshire SJ, Mulligan GA (2006) The biology of invasive alien plants in Canada. 4. Heracleum mantegazzianum Sommier & Levier. Can J Plant Sci 86:569–589

  42. Panetta FD, Randall RP (1994) An assessment of the colonizing ability of Emex australis. Aust J Ecol 19:76–82

  43. Panetta FD, Mackey AP, Virtue JG, Groves RH (2001) Weed risk assessment: core issues and future directions. In: Groves RH, Panetta FD, Virtue JG (eds) Weed risk assessment. CSIRO, Collingwood, pp 231–240

  44. Perry DA (1998) The scientific basis of forestry. Annu Rev Ecol Syst 29:435–466

  45. Pheloung PC (2001) Weed risk assessment for plant introductions to Australia. In: Groves RH, Panetta FD, Virtue JG (eds) Weed risk assessment. CSIRO, Collingwood, pp 231–240

  46. Pimentel D, Zuniga R, Monison D (2005) Update on the environmental and economic costs associated with alien invasive species in the United States. Ecol Econ 52(3):273–288

  47. Rejmanek M, Richardson DM, Higgins SI, Pitcairn MJ, Grotkopp E (2005) Ecology of invasive plants: state of the art. In: Mooney HA, Mack RN, McNeely JA, Neville L, Schei PJ, Waage JK (eds) Invasive alien species: a new synthesis. Island Press, Washington, DC, pp 104–161

  48. Robinson RG (1978) Production and culture. Sunflower science and technology. American Society of Agronomy. Crop Science Society of America, Soil Science Society of America, Madison

  49. Rouget M, Richardson DM (2003) Inferring process from pattern in plant invasions: a semimechanistic model incorporating propagule pressure and environmental factors. Am Nat 162:713–724

  50. Simberloff D (1988) The contribution of population and community biology to conservation science. Annu Rev Ecol Syst 19:473–511

  51. Simberloff D (1989) Which insect introductions succeed and which fail? In: Drake JA, Mooney HA, di Castri F, Groves RH, Kruger FJ, Rejmanek M, Williamson M (eds) Biological invasions: a global perspective. Wiley, Chichester, pp 61–75

  52. Smith CS, Lonsdale WM, Fortune J (1999) When to ignore advice: invasion prediction and decision theory. Biol Invasions 1:89–96

  53. Snow AA, Andow DA, Gepts P et al (2005) Genetically engineered organisms and the environment: current status and recommendations. Ecol Appl 15:377–404

  54. Tielborger K, Kamon R (2000) Temporal environmental variation tips the balance between facilitation and interference in desert plants. Ecology 81:1544–1553

  55. Veltman CJ, Nee S, Crawley MJ (1996) Correlates of introduction success in exotic New Zealand birds. Am Nat 147:542–557

  56. Von Holle B, Simberloff D (2005) Ecological resistance to biological invasion overwhelmed by propagule pressure. Ecology 86:3212–3218

  57. Walton CS (2001) Implementation of a permitted list approach to plant introductions to Australia. In: Groves RH, Panetta FD, Virtue JG (eds) Weed risk assessment. CSIRO, Collingwood, pp 93–99

  58. Weber E (2003) Invasive plant species of the world. A reference guide to environmental weeds. CABI, Wallingford

  59. Wheeler WA (1950) Forage and pasture crops. A handbook of information about the grasses and legumes grown for forage in the United States. Van Nostrand, New York

  60. Wilson HK, Myers WM (1954) Field crop production: agronomic principles and practices. Lippincott, Chicago

  61. Woodward FI (1990) The impact of low-temperatures in controlling the geographical distribution of plants. Philos Trans R Soc Lond B Biol Sci 326:585–593

  62. Zar JH (1996) Biostatistical analysis, 2nd edn. Prentice Hall, Upper Saddle River

Download references


We thank R. A. Black, R. M. Hannan, C. L. Kinter, E. L. Minton, R. R. Pattison and R. B. Pratt for their support and comments throughout the project. R. Colautti provided helpful comments on an earlier draft of the manuscript. K. Tetrich and the USDA Plant Introduction Facility in Central Ferry, Washington provided essential help. Finally, we are grateful to numerous volunteers, who assisted with the implementation and harvesting of these experiments. This research was supported by grants to M. S. M. from the Betty Higinbotham Trust and a Natural Resources Conservation Grant at Washington State University. Experiments reported in this work comply with the current laws of the United States of America.

Author information

Correspondence to Mark S. Minton.

Additional information

Communicated by John Silander.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary material (DOC 245 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Minton, M.S., Mack, R.N. Naturalization of plant populations: the role of cultivation and population size and density. Oecologia 164, 399–409 (2010).

Download citation


  • Environmental stochasticity
  • Field trials
  • Founder population
  • Invasion
  • Propagule pressure