Environmental Management

, Volume 62, Issue 6, pp 1168–1185 | Cite as

Managing Urban Plant Invasions: a Multi-Criteria Prioritization Approach

  • Luke J. PotgieterEmail author
  • Mirijam Gaertner
  • Ulrike M. Irlich
  • Patrick J. O’Farrell
  • Louise Stafford
  • Hannah Vogt
  • David M. Richardson


Alien plant invasions in urban areas can have considerable impact on biodiversity and ecosystem services (ES). Managing urban plant invasions is particularly challenging given the complex interactions between ecological, economic and social elements that exist in the urban milieu. Strategic landscape-scale insights are crucial for guiding management, as are tactical site-scale perspectives to plan and coordinate control efforts on the ground. Integrating these requirements to enhance management efficiency is a major challenge. Decision-support models have considerable potential for guiding and informing management strategies when problems are complex. This study uses multi-criteria decision tools to develop a prioritization framework for managing invasive alien plants (IAPs) in urban areas at landscape and local scales. We used the Analytic Hierarchy Process (AHP; a multi-criteria decision support model) to develop and rank criteria for prioritising IAP management in the City of Cape Town (CoCT), South Africa. Located within a global biodiversity hotspot, Cape Town has a long history of alien plant introductions and a complex socio-political make-up, creating a useful system to explore the challenges associated with managing urban plant invasions. To guide the prioritization of areas for IAP management across the CoCT, a stakeholder workshop was held to identify a goal and criteria for consideration, and to assess the relative importance given to each criterion in IAP management. Workshop attendees were drawn from multiple disciplines involved with different aspects of IAP research and management: government departments, scientists and researchers, and managers with a diverse set of skills and interests. We selected spatial datasets and applied our multi-criteria decision analysis in a Geographic Information System (GIS) to develop a landscape-scale prioritization map. To address issues relevant in an urban setting, we also modified an existing IAP management framework to develop a tactical (site-level) prioritization scheme for guiding on-the-ground control operations. High-priority sites for IAP management were identified at landscape- and local scales across the study area. Factors related to safety and security emerged as pivotal features for setting spatially-explicit priorities for management. The approach applied in this study can be useful for managers in all urban settings to guide the selection and prioritization of areas for IAP management.


Biological invasions Ecosystem services Invasive alien plants Multi-criteria analysis Prioritization Urban ecosystems 



Invited stakeholders for the prioritisation workshop were: David Le Maitre (CSIR), Brian van Wilgen (Centre for Invasion Biology), Nicola van Wilgen (SANParks), Greg Forsyth (CSIR), Patricia Holmes (City of Cape Town), Luca Afonso (Centre for Invasion Biology), Chandre Rhoda (City of Cape Town), Chad Cheney (SANParks), Karen Esler (Centre for Invasion Biology) and Leighan Mossop (City of Cape Town). Funding for this work was provided by the DST-NRF Centre of Excellence for Invasion Biology and the Working for Water Programme through their collaborative research project on “Integrated Management of invasive alien species in South Africa” and the National Research Foundation (grant 85417 to DMR). We thank the City of Cape Town (City Maps and Invasive Species Unit) and SANBI (BGIS) for access to spatial data.

Compliance with Ethical Standards

Conflict of Interest

The authors declare that they have no conflict of interest.

Supplementary material

267_2018_1088_MOESM1_ESM.docx (98 kb)
Supplementary Information


  1. Allsopp N, Anderson PML, Holmes PM, Melin A, Farrell PJO (2014) People, the Cape floristic region, and sustainability. In: Allsopp N, Colville JF, Verboom GA (eds) Fynbos ecology, evolution and conservation of a megadiverse region. Oxford University Press, Oxford, UK, pp 337–362CrossRefGoogle Scholar
  2. Alston KP, Richardson DM (2006) The roles of habitat features, disturbance, and distance from putative source populations in structuring alien plant invasions at the urban/wildland interface on the Cape Peninsula, South Africa. Biol Conserv 132:183–198. CrossRefGoogle Scholar
  3. Anderson PML, O’Farrell PJ (2012) An ecological view of the history of the establishment of the City of Cape Town. Ecol Soc 17(3):28. CrossRefGoogle Scholar
  4. Aronson MFJ, La Sorte FA, Nilon CH, Katti M, Goddard MA, Lepczyk CA, Warren PS, Williams NSG, Cilliers S, Clarkson B, Dobbs C, Dolan R, Hedblom M, Klotz S, Kooijmans JL, Kuhn I, MacGregor-Fors I, McDonnell M, Mortberg U, Pyšek P, Siebert S, Sushinsky J, Werner P, Winter M (2014) A global analysis of the impacts of urbanization on bird and plant diversity reveals key anthropogenic drivers. Proc R Soc Lond 281:8. CrossRefGoogle Scholar
  5. Arroyo P, Tommelein ID, Ballard G (2015) Comparing AHP and CBA as decision methods to resolve the choosing problem in detailed design. J Constr Eng Manag 141:04014063. CrossRefGoogle Scholar
  6. Boraine A, Crankshaw O, Engelbrecht C, Gotz G, Mbanga S, Narsoo M, Parnell S (2006) The state of South African cities a decade after democracy. Urban Stud 43:259–284. CrossRefGoogle Scholar
  7. Cilliers SS, Cilliers J, Lubbe R, Siebert S (2012) Ecosystem services of urban green spaces in African countries—perspectives and challenges. Urban Ecosyst 16:681–702CrossRefGoogle Scholar
  8. CoCT (City of Cape Town) (2003). Biodiversity Strategy. Integrated Metropolitan Environmental Policy CoCT(City of Cape Town) (2003). Biodiversity Strategy. Integrated Metropolitan Environmental PolicyGoogle Scholar
  9. Cowling R, Richardson D (1995) Fynbos: South Africa’s unique floral kingdom. Fernwood Press, Cape TownGoogle Scholar
  10. Cronin K, Kaplan H, Gaertner M, Irlich UM, Hoffman MT (2017) Aliens in the nursery: assessing the attitudes of nursery managers to invasive species regulations. Biol Invasions 19:925–937. CrossRefGoogle Scholar
  11. De Lange WJ, Stafford WHL, Forsyth GG, Le Maitre DC (2012) Incorporating stakeholder preferences in the selection of technologies for using invasive alien plants as a bio-energy feedstock: applying the analytical hierarchy process. J Environ Manag 99:76–83. CrossRefGoogle Scholar
  12. Dickie IA, Bennett BM, Burrows LE, Nuñez MA, Peltzer DA, Porté A, Richardson DM, Rejmánek M, Rundel PW, van Wilgen BW (2014) Conflicting values: ecosystem services and invasive tree management. Biol Invasions 16:705–719CrossRefGoogle Scholar
  13. Eviner VT, Garbach K, Baty JH, Hoskinson SA (2012) Measuring the effects of invasive plants on ecosystem services: challenges and prospects. Invasive Plant Sci Manag 5:125–136CrossRefGoogle Scholar
  14. Forsyth DR (2013) Group dynamics (6th ed), Wadsworth Cengage Learning, Belmont, CaliforniaGoogle Scholar
  15. Forsyth GG, Le Maitre DC (2011) Prioritising national parks for the management of invasive alien plants: report on the development of models to prioritise invasive alien plant control operations, CSIR Natural Resources and the Environment Report number: CSIR/NRE/ECO/ER/2011/0036/B, CSIR, StellenboschGoogle Scholar
  16. Forsyth GG, Le Maitre DC, O’Farrell PJ, van Wilgen BW (2012) The prioritisation of invasive alien plant control projects using a multi-criteria decision model informed by stakeholder input and spatial data. J Environ Manag 103:51–57. CrossRefGoogle Scholar
  17. Forsyth GG, Le Maitre DC, van Wilgen BW (2009) Prioritising quaternary catchments for invasive alien plant control within the Fynbos and Karoo biomes of the Western Cape Province. CSIR Report CSIR/NRE/ECO/ER/2009/0094/B. Natural Resources and the Environment, CSIR, StellenboschGoogle Scholar
  18. Fox AM, Gordon DR (2009) Approaches for assessing the status of nonnative plants: a comparative analysis. Invasive Plant Sci Manag 2:166–184CrossRefGoogle Scholar
  19. Funk JL, Matzek V, Bernhardt M, Johnson D (2013) Broadening the case for invasive species management to include impacts on ecosystem services. BioScience 64:58–63CrossRefGoogle Scholar
  20. Gaertner M, Larson BMH, Irlich UM, Holmes PM, Stafford L, van Wilgen BW, Richardson DM (2016) Managing invasive species in cities: a framework from Cape Town, South Africa. Landsc Urban Plan 151:1–9. CrossRefGoogle Scholar
  21. Gaertner M, Novoa A, Fried J, Richardson DM (2017) Managing invasive species in cities: a decision support framework applied to Cape Town. Biol Invasions 19:3707–3723CrossRefGoogle Scholar
  22. Gaston KJ, Ávila-Jiménez ML, Edmondson JL (2013) Managing urban ecosystems for goods and services. J Appl Ecol 50:830–40CrossRefGoogle Scholar
  23. Goodness J, Anderson P (2013) Local assessment of Cape Town: navigating the management complexities of urbanization, biodiversity, and ecosystem services in the cape floristic region. In: Elmqvist T, Fragkias M, Goodness J, et al. (eds) Urbanization, biodiversity and ecosystem services: challenges and opportunities. Springer, Dordrecht, pp 461–484CrossRefGoogle Scholar
  24. Grice AC (2000) Weed management in Australian rangelands. In: Sindel BM (ed) Australian weed management systems. R.G. and F.J. Richardson, Melbourne, pp 431–458Google Scholar
  25. Guerry AD, Polasky S, Lubchenco J et al. (2015) Natural capital and ecosystem services informing decisions: from promise to practice. Proc Natl Acad Sci USA 112:7348–7355CrossRefGoogle Scholar
  26. Higgins SI, Richardson DM, Cowling RM (2000) Using a dynamic landscape model for planning the management of alien plant invasions. Ecol Appl 10:1833–1848CrossRefGoogle Scholar
  27. Hohmann MG, Just MG, Frank PJ, Wall WA, Gray JB (2013) Prioritizing invasive plant management with multi-criteria decision analysis. Invasive Plant Sci Manag 6:339–351. CrossRefGoogle Scholar
  28. Holmes PM, Rebelo AG, Dorse C, Wood J (2012) Can Cape Town as unique biodiversity be saved? Balancing conservation imperatives and development needs Ecol Soc 17:28. CrossRefGoogle Scholar
  29. Irlich UM, Potgieter L, Stafford L, Gaertner M (2017) Recommendations for municipalities to become compliantwith national legislation on biological invasions Bothalia 47:1–11. CrossRefGoogle Scholar
  30. Januchowski-Hartley SR, Visconti P, Pressey RL (2011) A systematic approach for prioritizing multiple management actions for invasive species. Biol Invasions 13:1241–53CrossRefGoogle Scholar
  31. Le Maitre DC, Gaertner M, Marchante E, Ens E, Holmes PM, Pauchard A, O’Farrell PJ, Rogers AM, Blanchard R, Blignaut J, Richardson DM (2011) Impacts of invasive Australian acacias: implications for management and restoration. Divers Distrib 17:1015–1029CrossRefGoogle Scholar
  32. Littell JS, Peterson DL, Riley KL et al. (2016) Fire and drought. In: Vose JM, Clark JS, Luce CH, Patel-Weynard T (eds) Effects of drought on forests and rangelands in the United States: a comprehensive science synthesis. U.S. Department of Agriculture, Forest Service, Washington DC, pp 135–154Google Scholar
  33. Mace G, Masundire H, Baillie J, Ricketts T, Brooks T, Hoffmann M, Stuart S, Balmford A, Purvis A, Reyers B, Wang J, Revenga C, Kennedy E, Naeem S, Alkemade R, Allnutt T, Bakarr M, Bond W, Chanson J, Cox N, Fonseca G, Hilton-Taylor C, Loucks C, Rodrigues A, Sechrest W, Stattersfield A, van Rensburg BJ, Whiteman C (2005) Ecosystems and human well-being: current state and trends: findings of the condition and trends working group. Island Press, Washington, DCGoogle Scholar
  34. McLean P, Gallien L, Wilson JRU, Gaertner M, Richardson DM (2017) Small urban centres as launching sites for plant invasions in natural areas: insights from South Africa. Biol Invasions 19:3541–3555CrossRefGoogle Scholar
  35. Nielsen AM, Fei S (2015) Assessing the flexibility of the analytic hierarchy process for prioritization of invasive plant management. NeoBiota 27:25–36. CrossRefGoogle Scholar
  36. Nunan F, Campbell A, Foster E (2012) Environmental mainstreaming: the organizational challenges of policy integration. Public Adm Dev 32:262–277. CrossRefGoogle Scholar
  37. O’Farrell PJ, Anderson PML, Le Maitre DC, Holmes PM (2012) Insights and opportunities offered by a rapid ecosystem service assessment in promoting a conservation agenda in an urban biodiversity hotspot. Ecol Soc 17(3):1–25. CrossRefGoogle Scholar
  38. Piracha AL, Marcotullio PJ (2003) Urban ecosystem analysis: identifying tools and methods. United Nations University Institute for Advanced Studies, Tokyo, JapanGoogle Scholar
  39. Potgieter LJ, Kueffer C, Larson BMH, Livingston S, O’Farrell P, Gaertner M, Richardson DM (2017) Alien plants as mediators of ecosystem services and disservices in urban systems: a global review. Biol Invasions 19:3571–3588CrossRefGoogle Scholar
  40. Potgieter LJ, Gaertner M, O’Farrell PJ Richardson DM (2018) Perceptions of impact: invasive alien plants in the urban environment. J Environ Manage (in press) CrossRefGoogle Scholar
  41. Rebelo AG, Holmes PM, Dorse C, Wood J (2011) Impacts of urbanization in a biodiversity hotspot: conservation challenges in metropolitan Cape Town. S Afr J Bot 77(1):20–35. CrossRefGoogle Scholar
  42. Regan HM, Crookston JB, Swab R, Franklin J, Lawson DM (2010) Habitat fragmentation and altered fire regime create trade-offs for an obligate seeding shrub. Ecology 91:1114–1123CrossRefGoogle Scholar
  43. Richardson DM, Gelderblom C, van Wilgen BW, Trinder-Smith TH (1998) Managing biodiversity on the Cape Peninsula, South Africa: a hotspot under pressure. In: Rundel PW, Montenegro G, Jaksic F (eds) Landscape disturbance and biodiversity in Mediterranean-type ecosystems. Springer-Verlag, Berlin, pp 189–204CrossRefGoogle Scholar
  44. Richardson DM, Kluge RL (2008) Seed banks of invasive Australian Acacia species in South Africa: role in invasiveness and options for management. Perspect Plant Ecol Evol Syst 10:161–177. CrossRefGoogle Scholar
  45. Richardson DM, van Wilgen BW, Le Maitre DC, Higgins KB, Forsyth GG (1994) A computer-based system for fire management in the mountains of the Cape Province, South Africa. Int J Wildl Fire 4:17–32CrossRefGoogle Scholar
  46. Rittel HWJ, Webber MM (1973) Dilemmas in a general theory of planning. Policy Sci 4(2):155–169CrossRefGoogle Scholar
  47. Roura-Pascual N, Krug RM, Richardson DM, Hui C (2010) Spatially-explicit sensitivity analysis for conservation management: exploring the influence of decisions in invasive alien plant management. Divers Distrib 16:426–438. CrossRefGoogle Scholar
  48. Roura-Pascual N, Richardson DM, Krug RM et al. (2009) Ecology and management of alien plant invasions in South African fynbos: accommodating key complexities in objective decision making. Biol Cons 142:1595–1604. CrossRefGoogle Scholar
  49. Ruwanza S, Shackleton CM (2016) Incorporation of environmental issues in South Africa’s municipal integrated development plans.Int J Sust Dev World 23:28–39. CrossRefGoogle Scholar
  50. Saaty TL (1977) A scaling method for priorities in hierarchical structures. J Math Psychol 15:234–281CrossRefGoogle Scholar
  51. Saaty TL (1980) The analytic hierarchy process. McGraw-Hill Inc., New YorkGoogle Scholar
  52. Saaty TL (1990) How to make a decision: the analytic hierarchy process. Eur J Oper Res 48:9–26CrossRefGoogle Scholar
  53. Sitas N, Reyers B, Cundill G, Prozesky HE, Nel JL, Esler KJ (2016) Fostering collaboration for knowledge and action in disaster management in South Africa. Curr Opin Environ Sustain 19:94–102. CrossRefGoogle Scholar
  54. Swilling M (2010) Sustainability, poverty and municipal services: the case of Cape Town, South Africa. Sustain Dev 18:194–201. CrossRefGoogle Scholar
  55. Teie WC (2009) Fire manager’s handbook on veld and forest fires. Strategy, tactics and safety, 2nd edn. Southern African Institute of Forestry, Menlo ParkGoogle Scholar
  56. van Wilgen BW (2012) Evidence, perceptions, and trade-offs associated with invasive alien plant control in the Table Mountain National Park, South Africa. Ecol Soc 17:23. CrossRefGoogle Scholar
  57. van Wilgen BW (2009) The evolution of fire and invasive alien plant management practices in fynbos. S Afr J Sci 105:335–342Google Scholar
  58. van Wilgen BW, Cowling RM, Le Maitre DC (1998) Ecosystem services, efficiency, sustainability and equity: South Africa’s working for water programme. Trends Ecol Evol 13:378CrossRefGoogle Scholar
  59. van Wilgen BW, Forsyth GG, Prins P (2012) The management of fire-adapted ecosystems in an urban setting: the case of Table Mountain National Park, South Africa Ecol Soc 17:8. CrossRefGoogle Scholar
  60. van Wilgen BW, Reyers B, Le Maitre DC, Richardson DM, Schonegevel L (2008) A biome-scale assessment of the impact of invasive alien plants on ecosystem services in South Africa. J Environ Manag 89:336–349. CrossRefGoogle Scholar
  61. van Wilgen BW, Scott DF (2001) Managing fires on the Cape Peninsula: dealing with the inevitable. J Mediterr Ecol 2:197e208Google Scholar
  62. van Wilgen BW, Richardson DM, Seydack AHW (1994) Managing fynbos for biodiversity: constraints and options in a fire-prone environment. S Afr J Sci 90:322–329Google Scholar
  63. von der Lippe M, Kowarik I (2008) Do cities export biodiversity? Traffic as dispersal vector across urban–rural gradients. Divers Distrib 14:18–25CrossRefGoogle Scholar
  64. Wilson JRU, Ivey P, Manyama P, Nänni I (2013) A new national unit for invasive species detection, assessment and eradication planning. S Afr J Sci 109(5/6):1–13. CrossRefGoogle Scholar
  65. Zhou Y, Smith SJ, Zhao K et al. (2015) A global map of urban extent from nightlights. Environ Res Lett 10(5):54011. CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018
corrected publication August/2018

Authors and Affiliations

  • Luke J. Potgieter
    • 1
    Email author
  • Mirijam Gaertner
    • 1
    • 2
  • Ulrike M. Irlich
    • 1
    • 3
  • Patrick J. O’Farrell
    • 4
    • 5
  • Louise Stafford
    • 3
  • Hannah Vogt
    • 3
  • David M. Richardson
    • 1
  1. 1.Centre for Invasion Biology, Department of Botany and ZoologyStellenbosch UniversityMatielandSouth Africa
  2. 2.Nürtingen-Geislingen University of Applied Sciences (HFWU)NürtingenGermany
  3. 3.Invasive Species Unit, Environmental Resource Management Department, City of Cape TownWestlake Conservation OfficeCape TownSouth Africa
  4. 4.Natural Resources and Environment CSIRStellenboschSouth Africa
  5. 5.Percy FitzPatrick Institute of African OrnithologyUniversity of Cape TownRondeboschSouth Africa

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