Invasive alien plants of horticultural origin growing in Zimbabwe: Analysis of control mechanisms and management.

Alfred Maroyi

doi:10.51168/mpcrre56

Autori

Alfred Maroyi University of Fort Hare

DOI:

https://doi.org/10.51168/mpcrre56

Cuvinte cheie:

Alien species, floristic diversity, ornamental plants, plant invasion, taxonomy

Rezumat

Alien ornamental plants which escape from cultivation usually establish themselves and invade other habitats with far-reaching ecological and economic consequences. The current study, conducted in Zimbabwe, assessed the diversity of invasive alien ornamental plants in the country, the life forms of the species, their continents of origin, preferred invasion habitats, management and spread of the species. This study therefore focused on alien ornamental plant species which reproduce or spread without continued human help. An extensive literature review resulted in the identification of 41 invasive alien plant species used as ornamentals in Zimbabwe. Documented species belong to gymnosperms (4.9%), ferns (7.3%), monocots (9.8%) and eudicots (78%). More than half of the ornamental species (65.9%) are members of the Solanaceae family with six species, followed by Asteraceae and Fabaceae (five species each), Euphorbiaceae (three species), Cactaceae, Meliaceae, Pinaceae and Salvinaceae (two species each). About three-quarters of invasive alien species used as ornamentals in Zimbabwe (70.7%) are native to America, followed by Asia contributing six species (14.6%), Africa and Oceania with four species each (9.8%). Results of this study showed that degraded areas, roadsides, riparian habitats, woodland and forest formations are the preferred invasion habitats of invasive alien species used as ornamentals in Zimbabwe. Results of this study are important for monitoring existing alien plant species in the country, new introductions, and managing biological invasions. A better understanding of their establishment, spread, social and economic impacts, and distributional changes over time is vital for making informed decisions about alien plant species.

Biografie autor

Alfred Maroyi, University of Fort Hare

is a Professor of Botany in the Department of Biotechnology and Biological Sciences, University of Fort Hare.

Referințe

1. Angiosperm Phylogeny Group. (2016). An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG IV. Botanical Journal of the Linnean Society, 181(1), 1–20. https://doi.org/10.1111/boj.12385

2. Biegel, H.M. (1977). Checklist of ornamental plants used in Rhodesian parks and gardens. Rhodesia Agricultural Journal Research Report No. 3. Department of Research and Specialist Services, Salisbury.

3. Biegel, H.M. (1980). Common and botanical names of garden plants in Zimbabwe. Zimbabwe Agricultural Journal Research Report No. 4. Department of Research and Specialist Services, Harare.

4. Christenhusz, M.J.M., and Byng, J.W. (2016). The number of known plant species in the world and its annual increase. Phytotaxa, 261(3), 201–217. https://doi.org/10.11646/phytotaxa.261.3.1

5. Clout, M.N., and Williams, P.A. (2009). Invasive species management: A handbook of principles and techniques. Oxford University Press, Oxford.

6. Drummond, R.B. (1972). A list of Rhodesian legumes. Kirkia, 8(2), 209-229.

7. Drummond, R.B. (1975). A list of trees, shrubs and woody climbers indigenous or naturalized in Rhodesia. Kirkia, 10(1), 229–286.

8. Dubyna, D.V., Dziuba, T.P., Iemelianova, S.M., Protopopova, V.V., and Shevera, M.V. (2022). Alien species in the pioneer and ruderal vegetation of Ukraine. Diversity, 14, 1085. https://doi.org/10.3390/d14121085

9. Gazoulis, I., Antonopoulos, N., Kanatas, P., Karavas, N., Bertoncelj, I., and Travlos, I. (2022). Invasive alien plant species: Raising awareness of a threat to biodiversity and ecological connectivity (EC) in the Adriatic-Ionian region. Diversity, 14, 387. https://doi.org/10.3390/d14050387

10. Gwitira, I., Murwira, A., Shekede, M., Masocha, M., and Chapano, C. (2014). Precipitation of the warmest quarter and temperature of the warmest month are key to understanding the effect of climate change on plant species diversity in southern African savannah. African Journal of Ecology, 52, 209–216. https://doi.org/10.1111/aje.12105

11. Hasanuzzaman, M., Araújo, S., and Gill, S.S. (2020). The plant family Fabaceae: Biology and physiological responses to environmental stresses. Springer, Singapore

12. Hejda, M., Chytrý, M., Pergl, J., and Pyšek, P. (2015). Native-range habitats of invasive plants: Are they similar to invaded range habitats and do they differ according to the geographical direction of invasion? Diversity and Distributions, 21, 312–321. https://doi.org/10.1111/ddi.12269

13. Holmes, P.M., Esler, K.J., Gaertner, M., Gaerts, S., Hall, S.A., Nsikani, M.M., Richardson, D. M., and Ruwanza, S. (2020). Biological invasions and ecological restoration in South Africa. In: Van Wilgen, B.W., Measey, J., Richardson, D.M., Wilson, J.R., and Zengeya, T.A. (editors). Biological invasions in South Africa. Springer, Cham, pp. 665-700. https://doi.org/10.1007/978-3-030-32394-3_23

14. Hulme, P. E., Brundu, G., Carboni, M., Dehnen-Schmutz, K., Dullinger, S., Early, R., Essl, F., Gonzalez-Moreno, P., Groom, Q. J., Kueffer, C., Kuhn, I., Maurel, N., Novoa, A., Pergl, J., Pysek, P., Seebens, H., Touza, J. M., Van Kleunen, M., and Verbrugge, L.N. H. (2018). Integrating invasive species policies across ornamental horticulture supply chains to prevent plant invasions. Journal of Applied Ecology, 55, 92–98. https://doi Org/10.1111/1365‐2664.12953

15. Hyde, M.A., Wursten, B.T., Ballings, P., and Palgrave, C.M. (2026). Flora of Zimbabwe. Available from: https:// www.zimbabweflora.co.zw, accessed on 17 May 2026

16. Kachena, L., and Shackleton, R. T. (2024). The impact of the invasive alien plant Vernonanthura polyanthes on conservation and livelihoods in the Chimanimani uplands of Zimbabwe. Biological Invasions, 26, 1749–1767. https://doi.org/10.1007/s10530-024-03275-9

17. Kowarik, I. (2005). Urban ornamentals escaped from cultivation. In: Gressel, J. (editor). Crop ferality and volunteerism. CRC Press, Boca Raton, pp. 97-121.

18. Li, Y., Cheng, Z., Smith, W. A., Ellis, D. R., Chen, Y., Zheng, X., Pei, Y., Luo, K., Zhao, D., Yao, Q., Duan, H., and Li, Q. (2004). Invasive ornamental plants: Problems, challenges, and molecular tools to neutralize their invasiveness. Critical Reviews in Plant Science, 23(5), 381-389. https://doi.org/10.1080/07352680490505123

19. Mapaura, A., and Timberlake, J. (2004). A checklist of Zimbabwean vascular plants. Southern African Botanical Diversity Network Report No. 33, SABONET, Pretoria.

20. Maroyi, A. (2006). A preliminary checklist of naturalized and introduced plants in Zimbabwe. Kirkia, 18, 177-247.

21. Maroyi, A. (2009). Traditional homegardens and rural livelihoods in Nhema, Zimbabwe: A sustainable agroforestry system. International Journal of Sustainable Development and World Ecology, 16, 1-8. https://doi.org/10.1080/13504500902745895

22. Maroyi, A. (2012a). Garden plants in Zimbabwe: Their ethnomedicinal uses and reported toxicity. Ethnobotany Research and Applications, 10, 45-57. https://doi.org/10.17348/era.10.0.045-057

23. Maroyi, A. (2012b). The casual, naturalised and invasive alien flora of Zimbabwe based on herbarium and literature records. Koedoe, 54(1), Art.#1054. https://doi.org/10.4102/koedoe.v54i1.1054

24. Maroyi, A. (2013). Use and management of homegarden plants in Zvishavane District, Zimbabwe. Tropical Ecology, 54, 191-203.

25. Maroyi, A. (2015). Exotic Acacia species in Zimbabwe: A historical and ecological perspective. Studies on Ethnomedicine, 9, 391-399. https://doi.org/10.1080/09735070.2015.11905457

26. Maroyi, A. (2017). Data on introduced plants in Zimbabwe: Floristic changes and patterns of collection based on historical herbarium records. Data in Brief, 15, 348-369. https://doi.org/10.1016/j.dib.2017.09.046

27. Maroyi, A. (2022). Alien flora of Zimbabwe: Data derived from herbarium specimens. Data in Brief, 42, 108186. https://doi.org/10.1016/j.dib.2022.108186

28. Maroyi, A. (2026). Alien flora in Zimbabwe: An updated checklist. African Biodiversity and Conservation, 56(2), aX. http:// dx.doi.org/10.38201/abc. v56.2.aX

29. Maroyi, A., Wong, L.J., and Pagad, S. (2019). GRIIS checklist of introduced and invasive species: Zimbabwe: Version 1.1. Invasive Species Specialist Group ISSG, Checklist Dataset; 2019. Available from: https://doi.org/10.15468/cklmhe, accessed on 12 May 2026

30. Meddour, R., Sahar, O., and Fried, G. (2020). A preliminary checklist of the alien flora of Algeria (North Africa): Taxonomy, traits and invasiveness potential. Botany Letters, 167, 453–470. https://doi.org/10.1080/23818107.2020.1802775

31. Mengistu, A.G., Tesfuhuney, W.A., Steyn, S.A., and Tfwala, C. M. (2025). An overview of the distribution and impacts of invasive alien plant species (IAPS) in South Africa. Acta Oecologica, 128, 104112. https://doi.org/10.1016/j.actao.2025.104112

32. Mokotjomela, T.M., Rahlao, S.J., Vukeya, L.R., Baltzinger, C., Mangane, L.V., Willis, C.K., and Mutshinyalo, T.M. (2023). The diversity of alien plant species in South Africa’s national botanical and zoological gardens. Diversity, 15, 407. https://doi.org/10.3390/d15030407

33. Mullin, L.J. (2000). Conifers in Zimbabwe. Kirkia, 17(2), 199–217.

34. Mupfiga, U.N., Mutanga, O., Dube, T., and Kowe, P. (2022). Spatial clustering of vegetation fire intensity using MODIS satellite data. Atmosphere, 13, 1972. https://doi.org/10.3390/atmos13121972

35. Mupfiga, U.N., Mutanga, O., and Dube, T. (2025). Assessing drivers of vegetation fire occurrence in Zimbabwe: Insights from MaxEnt modelling and historical data analysis. Remote Sensing Applications Society and Environment, 37, 101404. https://doi.org/10.1016/j.rsase.2024.101404

36. Mupangwa, W., Chipindu, L., Ncube, B., Mkuhlani, S., Nhantumbo, N., Masvaya, E., Ngwira, A., Moeletsi, M., Nyagumbo, I., and Liben, F. (2023). Temporal changes in minimum and maximum temperatures at selected locations of southern Africa. Climate, 11, 84. https://doi.org/10.3390/cli11040084

37. Omer, A., Kordofani, M., Gibreel, H.H., Pyšek, P., and Van Kleunen, M. (2021). The alien flora of Sudan and South Sudan: Taxonomic and biogeographical composition. Biological Invasions, 23, 2033–2045. https://doi.org/10.1007/s10530-021-02495-7

38. Palgrave, M.C. (2002). Keith Coates Palgrave trees of southern Africa. Struik Publishers, Cape Town.

39. Pergl, J., Sádlo, J., Petřík, P., Danihelka, J., Chrtek, Jr., Hejda, M., Moravcová, L., Perglová, I., Štajerová, K., and Pyšek, P. (2016). Dark side of the fence: Ornamental plants as a source of wild-growing flora in the Czech Republic. Preslia, 88, 163–184.

40. Pope, G.V., and Pope, D.G. (1998). Collecting localities in the Flora Zambesiaca area. Flora Zambesiaca Management Committee, Royal Botanic Gardens, Kew, Richmond

41. Potgieter, L.J., Shrestha, N., and Cadotte, M.W. (2021). Prioritizing terrestrial invasive alien plant species for management in urban ecosystems. Journal of Applied Ecology, 59, 872–883. https://doi.org/10.1111/1365-2664.14103

42. POWO. (2026). Plants of the world Online. Available from: http://www.plantsoftheworldonline.org/, accessed on 11 May 2026

43. Pyšek, P., Richardson, D.M., Rejmanek, M., Webster, G.L., Williamson, M., and Kirschner, J. (2004). Alien plants in checklists and flora: Towards better communication between taxonomists and ecologists. Taxon, 53, 131–143. http://dx.doi.org/10.2307/4135498

44. Rai, P.K., and Singh, J.S. (2020). Invasive alien plant species: Their impact on environment, ecosystem services and human health. Ecological Indicators, 111, 106020. https://doi.org/10.1016/j.ecolind.2019.106020

45. Raicu, M., Urziceanu, M., Camen-Comănescu, P., and Toma, F. (2025). Spread and stability of ornamental alien plant species on urban and peri-urban riverbanks of Bucharest, Romania. Scientific Papers Series B Horticulture, 69(1), 665-673

46. Raicu, M., Camen-Comănescu, P., Urziceanu, M., Anastasiu, P., and Toma, F. (2024). The role of ornamental horticulture in plant invasion: A case study in Romania. Scientific Papers Series B Horticulture, 68(2), 717-726

47. Richardson, D.M., Pyšek, P., and Carlton, J.T. (2011). A compendium of essential concepts and terminology in biological invasions. In: Richardson, D.M. (editor). Fifty years of invasion ecology: The legacy of Charles Elton. Blackwell Publishing, Oxford; pp. 409–420. https://doi.org/10.1002/9781444329988.ch30

48. Richardson, D.M., Holmes, P.M., Esler, K.J., Galatowitsch, S.M., Stromberg, J.C., Kirkman, S.P., Pysek, P., and Hobbs, R.J. (2007). Riparian vegetation: Degradation, alien plant invasions, and restoration prospects. Diversity and Distributions, 13(1), 126-139. https://doi.org/10.1111/j.1366-9516.2006.00314.x

49. Rojas-Sandoval, J., and Ackerman, J.D. (2021). Ornamentals lead the way: Global influences on plant invasions in the Caribbean. NeoBiota, 64, 177–197. https://doi.org/10.3897/neobiota.64.62939

50. Rowe, N., and Speck, T. (2005). Plant growth forms: An ecological and evolutionary perspective. New Phytologist, 166, 61–72. https://doi.org/10.1111/j.1469-8137.2004.01309.x

51. Samuels, J. (2015). Biodiversity of food species of the Solanaceae family: A preliminary taxonomic inventory of subfamily Solanoideae. Resources, 4, 277-322. https://doi.org/10.3390/resources4020277

52. Seboko, T.C., Ruwanza, S., and Shackleton, C. (2024). The distribution and abundance of woody invasive alien plants in small towns in Eastern Cape Province, South Africa. Urban Ecosystems, 27, 1877–1890. https://doi.org/10.1007/s11252-024-01563-9

53. Semenya, S.S., and Maroyi, A. (2020). Assessment of useful alien plant species cultivated and managed in rural home gardens of Limpopo province, South Africa. Scientifica, Vol. 2020, No. ID 3561306. https://doi.org/10.1155/2020/3561306

54. Shekede, M.D., Gwitira, I., and Mamvura, C. (2019). Spatial modelling of wildfire hotspots and their key drivers across districts of Zimbabwe, southern Africa. Geocarto International, 36, 874–887. https://doi.org/10.1080/10106049.2019.1629642

55. Silva, A.C.N., Martinin, A., and Amaral, C.H. (2024). Invasive alien ornamental plants in Brazil: Impact, origin, preferred habitats and projections. Acta Botanica Brasilica, 38, e20230192. https://doi.org/10.1590/1677-941X-ABB-2023-0192

56. Sohrabi, S., Naqinezhad, A., Kortz, A., Hejda, M., Gherekhloo, J., Zand, E., Pergl, J., Brundu, G., and Pyšek, P. (2023). Alien flora of Iran: Species status, introduction dynamics, habitats and pathways. Biological Invasions, 25, 1359–1371. https://doi.org/10.1007/s10530-023-03001-x

57. Timberlake, J., Fagg, C., and Barnes, R. (1999). Field guide to the Acacias of Zimbabwe. CBC Publishing, Harare.

58. Underwood, E.C., Hollander, A.D., and Hahn, B.A. (2024). Assessing trends in tree cover, wildfire and population growth in Zimbabwe since 2000. Land, 13, 160. https://doi.org/10.3390/land13020160

59. Urziceanu, M., Camen-Comănescu, P., Nagodă, E., Raicu, M., Sîrbu, I.M., and Anastasiu, P. (2020). Updated list of non-native ornamental plants in Romania. Contributii Botanice, 55, 59–82. https://doi.org/10.24193/Contrib.Bot.55.4

60. Van Kleunen, M., Essl, F., Pergl, J., Brundu, G., Carboni, M., Dullinger, S., Early, R., González-Moreno, P., Groom, Q.J., Hulme, P.E., Kueffer, C., Kühn, I., Maurel, N., Novoa, A., Parepa, M., Pyšek, P., Seebens, H., and Dawson, W. (2018). The changing role of ornamental horticulture in alien plant invasions. Biological Reviews, 93(3), 1421-1437. https://doi.org/10.1111/brv.12402

61. Wild, H., Mavi, S., and Biegel, S.M. (1972). A Southern Rhodesia botanical dictionary of native and English plant names. Government Printer, Salisbury.

62. Zeil Rolfe, I.,·O’Loughlin, L., and Gooden, B. (2024). Habitat context and functional growth traits explain alien plant invader impacts on native vegetation communities. Biological Invasions, 26, 2663–2679. https://doi.org/10.1007/s10530-024-03338-x

63. Zhang, T., and Elomaa, P. (2024). Development and evolution of the Asteraceae capitulum. New Phytologist, 242, 33–48. https://doi.org/10.1111/nph.19590