ALIEN PLANTS AND REDUCTION OF AGRICULTURAL LAND.pptx

ALIEN PLANTS AND REDUCTION OF AGRICULTURAL LAND

1. Grade 11: Human Impact on the enviroment ALIEN PLANTS AND REDUCTION OF AGRICULTURAL LAND Studio Shodwe

2. 02 What are Alien Plants? Alien Plants- refers to plants that do not naturally grow in South Africa, but are introduced in the country by humans (Prinzing et al,. 2002) Figure 1

3. 03 Characteristics of Alien Plants They have no natural predators in South Africa Rapidly grow and spread easily Outcompete indigenous plants They are often harmful to ecosystems (van Kleunen, Dawson & Maurel, 2016)

4. 04 Examples of Alien Plants in South Africa Lantana camara - it is poisonous to livestock (Vardien et al., 2012) Black Wattle (Acacia mearnsii)-invades grasslands and uses a lot of water (Gwate et al., 2021) Figure 2 Figure 3

5. 04 Blue Gum (Eucalyptus spp.) → uses huge amounts of water, dries up rivers (Visco, 2020) Prickly Pear (Opuntia ficus-indica) - forms dense thickets, makes grazing difficult (Albuquerque et al.,2020) Figure 4

6. Figure 6

7. 06 Environmental impact of Alien Plants in SA Reduces biodiversity by killing indigenous plants Consume a lot of water drying up rivers and dams Threaten endangered plant species (O’Connor & van Wilgen, 2020)

8. 08 Control Measures Enforce Legislation such as Biodiversity Act (2004) to regulates alien species Use biological control insects (serve as predator) used to limit alien plant spread Educate community regarding dangers of keeping alien plants, encourage involvement in clearing projects (Clewley et al., 2012)

9. ANY QUESTION?

10. References 09 Albuquerque, T. G., Pereira, P., Silva, M. A., Vicente, F., Ramalho, R., & Costa, H. S. (2020). Prickly pear. In Nutritional composition and antioxidant properties of fruits and vegetables (pp. 709-728). Academic Press. Clewley, G. D., Eschen, R., Shaw, R. H., & Wright, D. J. (2012). The effectiveness of classical biological control of invasive plants. Journal of Applied Ecology, 49(6), 1287-1295. [Figure 1 Invasive alien plants]. Available at: https://invasives.org.za/wp-content/uploads/2022/05/IAP-banner-Print-at-200-thumb-1.png .[Date accessed : 17 August 2025] [Figure 2 Black Wattle. Available at: https://keys.lucidcentral.org/keys/v3/eafrinet/weeds/key/weeds/Media/Html/images/Acacia_mearnsii_(Black_Wattle)/acacia_mearnsii2_-_FKS.jpg . [Date accessed: 18 August 2025] [Figure 3 Lantana camara]. Available at: https://www.bonsai-bci.com/images/species_guide/coniferous-flowering/lantana-camara.jpg .[Date accessed: 18 August 2025]

11. [Figure 4 Prickley pear]. Available at: https://cdn.britannica.com/31/100631-050-F219B9CB/Prickly-pear-cactus-Arizona.jpg . [Date accessed: 18 August 2025] [Figure 5 Blue Gum]. Available at: https://i.pinimg.com/originals/ae/7f/0e/ae7f0eb539a0e38536ee6da4cedee59a.jpg . [Date accessed: 18 August 2025] [Figure 6 of map showing extent of invasions in South Africa ]. Available at: https://www.researchgate.net/publication/216366296_Utilitarian_Perspective_of_the_Invasion_of_Some_South_African_Biomes_by_Acacia_mearnsii . [Date accessed: 18 August 2025] Gwate, O., Mantel, S. K., Gibson, L. A., Munch, Z., Gusha, B., & Palmer, A. R. (2021). The effects of Acacia mearnsii (black wattle) on soil chemistry and grass biomass production in a South African semi-arid rangeland: implications for rangeland rehabilitation. African Journal of Range & Forage Science, 38(4), 270-280. O’Connor, T. G., & van Wilgen, B. W. (2020). The impact of invasive alien plants on rangelands in South Africa. Biological Invasions in South Africa, 14, 459-487. Prinzing, A., Durka, W., Klotz, S., & Brandl, R. (2002). Which species become aliens?. Evolutionary Ecology Research, 4(3), 385-405.

12. van Kleunen, M., Dawson, W., & Maurel, N. (2016). Characteristics of successful alien plants. Invasion Genetics: The Baker and Stebbins Legacy, 40-56. Vardien, W., Richardson, D. M., Foxcroft, L. C., Thompson, G. D., Wilson, J. R. U., & Le Roux, J. J. (2012). Invasion dynamics of Lantana camara L.(sensu lato) in South Africa. South African Journal of Botany, 81, 81-94. Visco, L. (2020). Blue Gum. CSPA Quarterly, (27), 46-51.

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