Background: A biodiversity zonation in the Greater Fish River Canyon Landscape and delineation of environmentally sensitive areas along the Orange River was required for two conservation projects in the Ai-Ais-Richtersveld Transfrontier Park. Objectives: This required filling gaps in plant distribution data. Method: Field surveys of plants were undertaken during the period 2011-2013. Results: These field surveys generated two cross-border range extensions, which represented new records for Namibia (Ornithogalum decus-montium G.Will. and Salvia dentata Aiton). Five recently described or still undescribed plant species were collected (Chlorophytum boomense Kativu, Moraea thermarum Goldbl. & Mann. and three Oxalis species) and several range extensions within Namibia were recorded (Euclea asperrima Holzh., Euryops lateriflorus (L.f.) DC and Othonna cyclophylla Merxm.). Conclusion: These findings highlighted the biodiversity importance of this area at the junction of three major biomes (Succulent Karoo, Desert and Nama Karoo) in the Gariep Centre of Endemism. More stringent reviews of environmental impact assessments are required and associated environmental management guidelines need to be implemented to ensure these newly discovered and rare plants are adequately protected.