Namaqualand is situated in the Succulent Karoo Biome, a globally recognised biodiversity hotspot. The Kamiesberg mountain range in Namaqualand contains two vegetation systems heavily degraded by cultivation. The diverse floras are being converted into single woody species-dominated communities: Galenia africana in the lower-lying Karoo and Elytroppus rhinocerotis in Mediterranean-type mountainous Renosterveld. Traditional restoration practises often ignore the role of patch dynamics, and the principles of facilitation and succession in arid systems. We tested how best to use pioneer plants and biodegradable shelters (using boxes and brush-packs) to mimic patch dynamics for successful seedling establishment in two vegetation systems in close proximity along an aridity gradient. We conducted a factorial field experiment for three years, seeding 18-20 species from a variety of functional groups in three habitats: under pioneer plants, in areas of recently removed pioneer plants, and in open areas. The Karoo and Renosterveld gave contrasting results. Seeding under G. africana plants resulted in low numbers of establishment but excellent growth rates, whereas seeding under E. rhinocerotis was less effective. Seeding into areas of recently removed G. africana was less successful compared to seeding in open areas; and the opposite results were found with E. rhinocerotis. Succulent Aizoaceae species established successfully in the Karoo, whilst in Renosterveld, grasses and herbs established was greater. Our study showed that it is better to sow seeds into open areas with sheltering structures in the Karoo, including under G. africana. Whilst in Renosterveld, we recommend sowing seeds into the space of recently removed E. rhinocerotis.
Audio/Video, Conference Presentation, SER2019
Pre-approved for CECs under SER's CERP program
Society for Ecological Restoration