Tree visitation and potential seed dispersal of keystone Ficus species by vertebrates in an urban mosaic landscape in eastern South Africa

Abstract

Globally with the human population increase, urban expansion has increased, impacting biodiversity and ecosystem functions. Visitation of fruiting trees by vertebrate frugivores can influence the persistence of fleshy fruited trees and so further maintain frugivore communities in transformed landscapes. Figs (Ficus spp.) have been recognised as keystone plant resources that support diverse frugivorous vertebrate communities. Our main objective was to identify the frugivorous vertebrates visiting fruiting Ficus trees in an urban mosaic landscape of Durban, Ethekwini Municipality, KwaZulu-Natal, South Africa, using camera traps focused on focal fig trees. We quantified the diurnal and nocturnal frugivore visitation rates and levels of interactions. We analysed frugivore visits to 12 individual trees of five Ficus species between 2019 and 2020. During 3888 h, we recorded a total of 4,071 videos from camera traps with 10,016 visits and levels of interactions of three main vertebrate taxa (8958 fruit bat visits, 808 bird visits and 250 monkey visits). These were in five Ficus species (F. burkei, F. lutea, F. natalensis, F. sur and F. sycomorus). Of the bird species visiting, we identified a total of 34 species, but some species were unidentified. We recorded a total of 8958 visits by Wahlberg's epauletted fruit bats Epomophorus wahlbergi, and 250 visits by vervet monkeys Chlorocebus pygerythrus. The latter tended to stay for prolonged periods in the trees feeding. Our data showed the importance of fruiting fig trees for vertebrate frugivores in the urban mosaic landscape. This highlights the conservation implications of figs as keystone resources in the urban mosaic landscape. Our findings support the planting and conservation of native Ficus tree species in transformed urban mosaic landscapes for the persistence of forest species biodiversity.