The Study of Exotic and Invasive Plant Species in Gullele Botanic Garden, Addis Ababa, Ethiopia

Gullele Botanic Garden was established to preserve and safeguard indigenous, rare, endemic and endangered plant species that have economic significance. A study was conducted to identify and map non-native plant species that exist in various land use types, including natural vegetation, plantation, roadside, and garden edges. The research involved placing plots at different distances in each land use type and collecting vegetation data with geo-location information for exotic and invasive species. The data was analyzed using Sorensen's similarity index to measure the similarity between plant communities. Invasive species were identified using ArcGIS, and descriptive statistical methods were employed to analyze the remaining data. The recorded a total of 80 plant species belonging to 70 genera in 44 families in the garden, with Fabaceae and Asteraceae having the most species. Acacia decurrens, Acacia melanoxylon, Cuscuta campestris, Galinsoga parviflora, Nerium oleander, and Cyathula uncinulata are the most prevalent invasive or potentially invasive species among the species that have been documented. These species are spreading quickly and may displace native plant species if not properly managed. The study found that roadside and garden edge land use types had the most diverse exotic plants, with Acacia decurrens, Nerium oleander, Acacia melanoxylon, Agave species, Cyathula uncinulata, and Eucalyptus species being the most dominant exotic species in the garden. The total density of exotic species was 2.36 plants/m2. The study provides valuable information for managing and conserving both native and exotic plant species in the garden.