Characterisation of invasive plant proliferation within remnant riparian green corridors in Lusaka District of Zambia using Sentinel-2 imagery

Abstract

Natural riparian corridors can serve as biodiversity reservoirs in urban environments. Despite the many opportunities that riparian corridors present for biodiversity conservation within urban environments, they may present conservation challenges by providing a thriving hub for local and alien invasive plants. The aim of the study was to map and characterise the occurrence of local and alien invasive plants along the natural green riparian corridors in Lusaka district of Zambia. A combination of field surveys and remote sensing approaches using Sentinel-2 imagery were employed to conduct the vegetation mapping and characterise the invasive plant proliferation. Five local and nine alien invasive plant species were identified within the natural green riparian corridors at 23 field survey sites. A total of 108 plant species were recorded in the study area out of which 57 were grasses of the Poacea family, five were local invasive and nine were alien invasive plant species. Six of the invasive plant species were mapped using Sentinel-2 data. The study showed that 47.35% of areal extent of the natural green riparian corridors in Lusaka had invasive and alien plant presence. Invasive and alien plant richness was determined to affect non-invasive plant richness and diversity. There was no linear association between poverty and percentage cover of invasive plant species but percentage cover of invasive plants seemed to be concentrated around wards with a poverty headcount around 0.15. The outcomes of this research are relevant for the management of invasive species within natural green corridors in urban areas.