Investigating the influence of Opuntia fulgida on species diversity, abundance and soil nutrients: A case study of Guyu Communal Lands-Gwanda.
Natural Resources Unit and or Climate Change Unit, National University of Science and Technology (NUST), Bulawayo, Zimbabwe
Various invasive alien species cause significant ecological problems in many different forms and are a hazard to biodiversity. A once off study investigating the influence of invasive alien Opuntia fulgida on diversity, abundance of indigenous woody plants and soil nutrients was conducted in the South Western part of Zimbabwe. Randomized plots measuring 30m x 5m replicated 6 times (making a block of 900m2) were demarcated on of 4 different sites with an overall area of 3600m2. The 4 blocks were constituted of; 1) no presence of Opuntia fulgida infestation (control), 2) with low infestation, 3) medium infestation and 4) high levels of Opuntia fulgida infestation. Species diversity/abundance were measured and calculated in each block including the counting of any carcasses that was present. Soil samples were randomly collected from the surface (0-10cm) in each block to determine the levels of pH, N. P, K, Ca and Mg. Diversity and abundance of indigenous woody species and the levels of N declined with the increase in density levels of Opuntia fulgida. High numbers of carcasses were present in the blocks with high and medium density levels of Opuntia species and also, Mg increased in these blocks. Generally pH was low in all the blocks while levels of P. K and Ca were insignificant. The paper concluded by acknowledging that invasive alien Opuntia fulgida was indeed detrimental to the ecosystems and the environment. As a result, it was causing serious socio-economic problems for the villagers whose livelihood is at threat. Furthermore, the paper proposes the Zimbabwean government to intervene urgently by collaborating with the South African counterparts on the use of bio control (Dactylopius tomentosus) and / or consider the economic benefits of Opuntia species especial on the production of alcohol as a way to manage the problematic invasive Opuntia fulgida.