Role of Local Medium to Large Mammalian Species in Seed Dispersal of Fleshy‐Fruited Invasive Alien Plants in the Montane Grassland Biome of South Africa

Abstract

ABSTRACT Fleshy‐fruited invasive alien shrubs are an increasing problem in the grasslands of South Africa, where they alter vegetation and threaten biodiversity. They are predominantly bird‐dispersed in forest systems, but their spread in grassland ecosystems remains understudied, including their dispersal by mammals. Mammals can facilitate seed movement and promote germination, seedling emergence and seedling establishment, contributing to increased invasion. Our study aimed to determine the role of various terrestrial mammals in this process for fleshy‐fruited invasive alien plants present in montane grasslands. Faeces of eland ( Taurotragus oryx ), chacma baboon ( Papio ursinus ), domestic goat ( Capra hircus ) and black‐backed jackal ( Lupulella mesomelas ) were collected in the grasslands of the eastern Free State, South Africa. Seeds were removed from faeces, identified to species level, and planted in a greenhouse to determine seedling emergence success. Seeds of the invasive fleshy‐fruited species silver‐leaf cotoneaster Cotoneaster pannosus , yellow firethorn Pyracantha angustifolia and eglantine Rosa rubiginosa (all Rosaceae) were identified from the faeces together with the seeds of the indigenous star‐apple Diospyros austro‐africana . Seed composition in faeces samples differed significantly between mammalian species. There were no significant differences in seedling emergence between ingested P. angustifolia seed and manually de‐pulped controls, while there were significantly higher differences in C. pannosus seedling emergence compared with manually de‐pulped controls. Overall, seedling emergence from R. rubiginosa seeds in faeces was low (≤ 2%), similar to controls. Diospyros austro‐africana had the highest seedling emergence percentage for seeds from jackal and eland faeces. Locally found medium to large terrestrial mammals were shown to be significant dispersers of fleshy fruiting plants in the montane grasslands of South Africa, facilitating the spread of these invasive alien plant species.