Human perceptions of the costs and benefits of invasive alien plants in Vhembe Biosphere Reserve, Limpopo Province of South Africa

Abstract

Understanding the human dimensions of invasive alien plants could facilitate the development of effective control methods that incorporate human utilisation. We conducted household surveys in five villages within the Vhembe Biosphere Reserve in Limpopo province, South Africa. Households that participated were conveniently selected to assess rural people's perceptions and uses of 12 commonly occurring invasive alien plants. Using thematic analysis and chi-squared tests to categorise interview responses, the results show that more than 80% of the villagers use various invasive alien plants in their villages, but they are unaware the plants are invasive alien. The mostly known species, reported by all the respondents across all villages, were Solanum mauritianum, Eucalyptus paniculata, Psidium guava, and Pinus patula. Across all villages and species, nine benefits were identified: provisional (food, medicinal, fuelwood, construction timber, and fodder), regulating (shade and windbreak), and cultural (ornamental and traditional use). Seven costs were identified across all species, with Lantana camara having the highest costs (5 of 7 costs) compared to S. mauritianum, Casuarina cunninghamiana, and Jacaranda mimosifolia (1 of 7 cost). Across all species, control methods varied, with most villagers preferring mechanical cutting or chemical spraying of plants over burning, digging, and hand pulling. Our results show that L. camara, Acacia mearnsii, Caesalpinia decapetala, Rubus cuneifolius, and P. patula, have high benefits and costs, potentially making them conflict-generating species. The management of potential conflict-generating species requires user engagement to balance costs and benefits, with plant utilisation being the suggested control option.