Biological Invasions

, Volume 18, Issue 1, pp 73–87 | Cite as

Understanding and managing the introduction pathways of alien taxa: South Africa as a case study

  • Katelyn T. Faulkner
  • Mark P. Robertson
  • Mathieu Rouget
  • John R. U. Wilson
Original Paper


For the effective prevention of biological invasions, the pathways responsible for introductions must be understood and managed. However introduction pathways, particularly for developing nations, have been understudied. Using the Hulme et al. (J Appl Ecol 45:403–414, 2008) pathway classification, we assessed the South African introduction pathways in terms of the number of introductions, the invasion success of introduced taxa, how the pathways have changed over time, and how these factors vary for vertebrates, invertebrates and plants. Pathway and date of introduction, region of origin, distribution and invasion status data for 2111 alien taxa were extracted from databases. Most alien and invasive taxa were deliberately introduced and subsequently escaped captivity or cultivation. Pathway prominence also varied temporally and across organism types. Vertebrates and plants were largely escapes and although most plant escapes have become invasive, this is not the case for vertebrates. However the number of new plant and vertebrate escapes has increased over time. Invertebrates have been deliberately released or unintentionally introduced as contaminants or stowaways. For invertebrates the number of release, contaminant and stowaway introductions has increased, and most contaminants and stowaways have become invasive. As effective screening procedures are in place for invertebrates released for biological control, the major threats for South Africa are from vertebrate and plant escapes and invertebrate contaminants and stowaways. We recommend improvements to risk assessment and education to prevent escapes, and prioritised inspection strategies to reduce stowaway and contaminant introductions. Finally, as introduction pathways and introduced taxa change temporally, biosecurity decisions need to be informed by information on current and future pathways.


Biological invasions Biosecurity Pre-border control Invasion success Mode of introduction Date of introduction 



This work was supported by the South African National Department of Environment Affairs through its funding of the South African National Biodiversity Institute’s Invasive Species Programme. Additional funding was provided by the DST-NRF Centre for Invasion Biology. MR acknowledges funding from the South African Research Chairs Initiative of the Department of Science and Technology and National Research Foundation of South Africa. We thank Dian Spear for advice on data collection as well as Hildegard Klein and Angela Bownes for their help with additional information on biological control agents.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

10530_2015_990_MOESM1_ESM.docx (16 kb)
Supplementary material 1 (DOCX 16 kb)
10530_2015_990_MOESM2_ESM.docx (22 kb)
Supplementary material 2 (DOCX 21 kb)


  1. Areal FJ, Touza J, MacLeod A, Dehnen-Schmutz K, Perrings C, Palmieri MG, Spence NJ (2008) Integrating drivers influencing the detection of plant pests carried in the international cut flower trade. J Environ Manag 89:300–307CrossRefGoogle Scholar
  2. Bacon SJ, Bacher S, Aebi A (2012) Gaps in border controls are related to quarantine alien insect invasions in Europe. PLoS One 7:e47689PubMedPubMedCentralCrossRefGoogle Scholar
  3. Bewick V, Cheek L, Ball J (2004) Statistics review 8: qualitative data—tests of association. Crit Care 8:46–53PubMedPubMedCentralCrossRefGoogle Scholar
  4. Blackburn TM, Pyšek P, Bacher S, Carlton JT, Duncan RP, Jarošík V, Wilson JRU, Richardson DM (2011) A proposed unified framework for biological invasions. Trends Ecol Evol 26:333–339PubMedCrossRefGoogle Scholar
  5. Cassey P, Blackburn TM, Russell GJ, Jones KE, Lockwood JL (2004) Influences on the transport and establishment of exotic bird species: an analysis of the parrots (Psittaciformes) of the world. Glob Chang Biol 10:417–426CrossRefGoogle Scholar
  6. Crawley MJ (2007) The R Book. Wiley, ChichesterCrossRefGoogle Scholar
  7. Dehnen-Schmutz K, Touza J, Perrings C, Williamson M (2007) A century of the ornamental plant trade and its impact on invasion success. Divers Distrib 13:527–534CrossRefGoogle Scholar
  8. Essl F, Bacher S, Blackburn TM, Booy O, Brundu G, Brunel S, Cardoso A-C, Eschen R, Gallardo B, Galil B, García-Berthou E, Genovesi P, Groom Q, Harrower C, Hulme PE, Katsanevakis S, Kenis M, Kühn I, Kumschick S, Martinou AF, Nentwig W, O’Flynn C, Pagad S, Pergl J, Pyšek P, Rabitsch W, Richardson DM, Roques A, Roy HE, Scalera R, Schindler S, Seebens H, Vanderhoeven S, Vilá M, Wilson JRU, Zenetos A, Jeschke JM (2015) Crossing frontiers in tackling pathways of biological invasions. Bioscience  65:769–782Google Scholar
  9. Everett RA (2000) Patterns and pathways of biological invasions. Trends Ecol Evol 15:177–178CrossRefGoogle Scholar
  10. Everitt BS (1977) The analysis of contingency tables. Chapman and Hall Ltd, LondonCrossRefGoogle Scholar
  11. Faulkner KT, Spear D, Robertson MP, Rouget M, Wilson JRU (2015) An assessment of the information content of South African alien species databases.  Bothalia: Afr Biodivers Conserv 45:1–11. doi: 10.4102/abc.v45i1.1103
  12. Foxcroft LC, Richardson DM, Wilson JRU (2008) Ornamental plants as invasive aliens: problems and solutions in Kruger National Park, South Africa. Environ Manag 41:32–51CrossRefGoogle Scholar
  13. Gertzen E, Familiar O, Leung B (2008) Quantifying invasion pathways: fish introductions from the aquarium trade. Can J Fish Aquat Sci 65:1265–1273CrossRefGoogle Scholar
  14. Giliomee JH (2011) Recent establishment of many alien insects in South Africa—a cause for concern. African Entomol 19:151–155CrossRefGoogle Scholar
  15. Gonzalez-Nuñez X (2008) 15-year review: trade policy in South Africa. Trade and Industrial Policy Strategies, PretoriaGoogle Scholar
  16. Hastie T (2013) gam: generalized additive models. Accessed 3 July 2014
  17. Henderson L (2006) Comparisons of invasive plants in southern Africa originating from southern temperate, northern temperate and tropical regions. Bothalia 36:201–222CrossRefGoogle Scholar
  18. Herbert DG (2010) The introduced terrestrial mollusca of South Africa. South African National Biodiversity Institute, PretoriaGoogle Scholar
  19. Hulme PE (2006) Beyond control: wider implications for the management of biological invasions. J Appl Ecol 43:835–847CrossRefGoogle Scholar
  20. Hulme PE (2009) Trade, transport and trouble: managing invasive species pathways in an era of globalization. J Appl Ecol 46:10–18CrossRefGoogle Scholar
  21. Hulme PE, Bacher S, Kenis M, Klotz S, Kühn I, Minchin D, Nentwig W, Olenin S, Panov V, Pergl J, Pyšek P, Roques A, Sol D, Solarz W, Vilà M (2008) Grasping at the routes of biological invasions: a framework for integrating pathways into policy. J Appl Ecol 45:403–414CrossRefGoogle Scholar
  22. Katsanevakis S, Zenetos A, Belchior C, Cardoso AC (2013) Invading European seas: assessing pathways of introduction of marine aliens. Ocean Coast Manag 76:64–74CrossRefGoogle Scholar
  23. Kenis M, Rabitsch W, Auger-Rozenberg M-A, Roques A (2007) How can alien species inventories and interception data help us prevent insect invasions? Bull Entomol Res 97:489–502PubMedCrossRefGoogle Scholar
  24. Klein H (2011) A catalogue of the insects, mites and pathogens that have been used or rejected, or are under consideration, for the biological control of invasive alien plants in South Africa. African Entomol 19:515–549CrossRefGoogle Scholar
  25. Kolar CS, Lodge DM (2001) Progress in invasion biology: predicting invaders. Trends Ecol Evol 16:199–204PubMedCrossRefGoogle Scholar
  26. Kolar CS, Lodge DM (2002) Ecological predictions and risk assessment for alien fishes in North America. Science 298:1233–1236PubMedCrossRefGoogle Scholar
  27. Kraus F (2007) Using pathway analysis to inform prevention strategies for alien reptiles and amphibians. Manag Vertebr Invasive Species 21:94–103Google Scholar
  28. Kumschick S, Richardson DM (2013) Species-based risk assessments for biological invasions: advances and challenges. Divers Distrib 19:1095–1105CrossRefGoogle Scholar
  29. Lambdon PW, Lloret F, Hulme PE (2008) How do introduction characteristics influence the invasion success of Mediterranean alien plants? Perspect Plant Ecol Evol Syst 10:143–159CrossRefGoogle Scholar
  30. Lehan NE, Murphy JR, Thorburn LP, Bradley BA (2013) Accidental introductions are an important source of invasive plants in the continental United States. Am J Bot 100:1287–1293PubMedCrossRefGoogle Scholar
  31. Leung B, Lodge DM, Finnoff D, Shogren JF, Lewis MA, Lamberti G (2002) An ounce of prevention or a pound of cure: bioeconomic risk analysis of invasive species. Proc R Soc Lond B 269:2407–2413CrossRefGoogle Scholar
  32. Levine JM, D’Antonio CM (2003) Forecasting biological invasions with increasing international trade. Conserv Biol 17:322–326CrossRefGoogle Scholar
  33. Lockwood JL, Cassey P, Blackburn TM (2009) The more you introduce the more you get: the role of colonization pressure and propagule pressure in invasion ecology. Divers Distrib 15:904–910CrossRefGoogle Scholar
  34. MacIsaac HJ, Robbins TC, Lewis MA (2002) Modeling ships’ ballast water as invasion threats to the Great Lakes. Can J Fish Aquat Sci 59:1245–1256CrossRefGoogle Scholar
  35. Mack RN (2005) Predicting the identity of plant invaders: future contributions from horticulture. HortScience 40:1168–1174Google Scholar
  36. Mack RN, Erneberg M (2002) The United States naturalized flora: largely the product of deliberate introductions. Ann Missouri Bot Gard 89:176–189CrossRefGoogle Scholar
  37. Martin GD, Coetzee JA (2011) Pet stores, aquarists and the internet trade as modes of introduction and spread of invasive macrophytes in South Africa. Water SA 37:371–380CrossRefGoogle Scholar
  38. Mead A, Carlton JT, Griffiths CL, Rius M (2011) Introduced and cryptogenic marine and estuarine species of South Africa. J Nat Hist 45:2463–2524CrossRefGoogle Scholar
  39. Moran VC, Hoffmann JH, Zimmermann HG (2005) Biological control of invasive alien plants in South Africa: necessity, circumspection, and success. Front Ecol Environ 3:77–83CrossRefGoogle Scholar
  40. Moran VC, Hoffmann JH, Zimmermann HG (2013) 100 years of biological control of invasive alien plants in South Africa: history, practice and achievements. S Afr J Sci 109:1–6CrossRefGoogle Scholar
  41. Pheloung PC, Williams PA, Halloy SR (1999) A weed risk assessment model for use as a biosecurity tool evaluating plant introductions. J Environ Manag 57:239–251CrossRefGoogle Scholar
  42. Puth LM, Post DM (2005) Studying invasion: have we missed the boat? Ecol Lett 8:715–721CrossRefGoogle Scholar
  43. Pyšek P, Richardson DM, Pergl J, Jarošík V, Sixtová Z, Weber E (2008) Geographical and taxonomic biases in invasion ecology. Trends Ecol Evol 23:237–244PubMedCrossRefGoogle Scholar
  44. Pyšek P, Jarošík V, Pergl J (2011) Alien plants introduced by different pathways differ in invasion success: unintentional introductions as a threat to natural areas. PLoS One 6:e24890PubMedPubMedCentralCrossRefGoogle Scholar
  45. R Core Team (2013) R: a language and environment for statistical computing. Accessed 23 April 2014
  46. Reichard SH, White P (2001) Horticulture as a pathway of invasive plant introductions in the United States. Bioscience 51:103–113CrossRefGoogle Scholar
  47. Richardson DM, Pyšek P, Rejmánek M, Barbour MG, Panetta FD, West CJ (2000) Naturalization and invasion of alien plants: concepts and definitions. Divers Distrib 6:93–107CrossRefGoogle Scholar
  48. Richardson DM, Cambray JA, Chapman RA, Dean WRJ, Griffiths CL, Le Maitre DC, Newton DJ, Winstanley TJ (2003) Vectors and pathways of biological invasions in South Africa—past, present and future. In: Ruiz GM, Carlton JT (eds) Invasive species: vectors and management strategies. Island Press, Washington, pp 292–349Google Scholar
  49. Saccaggi DL, Pieterse W (2013) Intercepting aliens: insects and mites on budwood imported to South Africa. J Econ Entomol 106:1179–1189PubMedCrossRefGoogle Scholar
  50. Simberloff D (2006) Risk assessments, blacklists, and white lists for introduced species: Are predictions good enough to be useful? Agric Resour Econ Rev 35:1–10Google Scholar
  51. Simberloff D (2009) The role of propagule pressure in biological invasions. Annu Rev Ecol Evol Syst 40:81–102CrossRefGoogle Scholar
  52. Simberloff D, Martin J-L, Genovesi P, Maris V, Wardle DA, Aronson J, Courchamp F, Galil B, García-Berthou E, Pascal M, Pyšek P, Sousa R, Tabacchi E, Vilà M (2013) Impacts of biological invasions: what’s what and the way forward. Trends Ecol Evol 28:58–66PubMedCrossRefGoogle Scholar
  53. van Wilgen BW, Richardson DM, Le Maitre DC, Marais C, Magadlela D (2001) The economic consequences of alien plant invasions: examples of impacts and approaches to sustainable management in South Africa. Environ Dev Sustain 3:145–168CrossRefGoogle Scholar
  54. van Wilgen NJ, Wilson JRU, Elith J, Wintle BA, Richardson DM (2010) Alien invaders and reptile traders: what drives the live animal trade in South Africa? Anim Conserv 13:24–32CrossRefGoogle Scholar
  55. Westphal MI, Browne M, MacKinnon K, Noble I (2008) The link between international trade and the global distribution of invasive alien species. Biol Invasions 10:391–398CrossRefGoogle Scholar
  56. Williams PA, Newfield M (2002) A weed risk assessment system for new conservation weeds in New Zealand. Department of Conservation, WellingtonGoogle Scholar
  57. Wilson JRU, Dormontt EE, Prentis PJ, Lowe AJ, Richardson DM (2009) Something in the way you move: dispersal pathways affect invasion success. Trends Ecol Evol 24:136–144PubMedCrossRefGoogle Scholar
  58. Wittenberg R, Cock MJW (2005) Best practices for the prevention and management of invasive alien species. In: Mooney HA, Mack RN, McNeely JA, Neville LE, Schei PJ, Wage JK (eds) Invasive alien species: a new synthesis. Island Press, Washington, pp 209–232Google Scholar
  59. Wojtasik EM (2013) Richness and diversity of alien ethnomedicinal plant taxa used and sold for traditional medicine in South Africa. Dissertation, University of WitwatersrandGoogle Scholar
  60. Xu H, Qiang S, Han Z, Guo J, Huang Z, Sun H, He S, Ding H, Wu H, Wan F (2006) The status and causes of alien species invasion in China. Biodivers Conserv 15:2893–2904CrossRefGoogle Scholar
  61. Zuur AF, Ieno EN, Walker NJ, Saveliev AA, Smith GM (2009) Mixed effects models and extensions in ecology with R. Springer, New YorkCrossRefGoogle Scholar

Copyright information

© Springer International Publishing Switzerland 2015

Authors and Affiliations

  • Katelyn T. Faulkner
    • 1
    • 2
  • Mark P. Robertson
    • 2
  • Mathieu Rouget
    • 3
  • John R. U. Wilson
    • 1
    • 4
  1. 1.Invasive Species Programme, South African National Biodiversity InstituteKirstenbosch Research CentreClaremontSouth Africa
  2. 2.Centre for Invasion Biology, Department of Zoology and EntomologyUniversity of PretoriaHatfieldSouth Africa
  3. 3.Centre for Invasion Biology, School of Agricultural, Earth and Environmental SciencesUniversity of KwaZulu-NatalScottsvilleSouth Africa
  4. 4.Centre for Invasion Biology, Department of Botany and ZoologyStellenbosch UniversityMatielandSouth Africa

Personalised recommendations