Browsing by Author "Moir, Monika Ilka"

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    Evaluating the effects of biogeography and fragmentation on the taxonomic, functional, and genetic diversity of forest-utilising bats in a South African biodiversity hotspot
    (Stellenbosch : Stellenbosch University, 2020-12) Moir, Monika Ilka; Rambau, Ramugondo Victor; Cherry, Michael ; Richards, Leigh Rosanne; Stellenbosch University. Faculty of Science. Dept. of Botany and Zoology.
    ENGLISH ABSTRACT: Bats are a highly diverse mammalian order and are some of the most economically important non-domesticated vertebrates, providing many ecosystem services that contribute to the global economy. Yet, they remain a largely understudied taxon, particularly in the Eastern Cape province of South Africa, in which basic surveys of bat assemblages utilising indigenous forests are lacking. Indigenous forests constitute South Africa’s smallest and most fragmented biome yet support disproportionally high biodiversity. They have been fragmented throughout most of their evolutionary history due to global palaeoclimatic shifts; the responses of bats to forest fragmentation and historical climatic shifts in this habitat have been poorly studied. This study addresses these gaps with the broad aims of compiling a species inventory from 17 forests across the Eastern Cape and KwaZulu-Natal provinces; assessing the effects of fragmentation and biogeography on taxonomic and functional diversity of bat assemblages; and determining how genetic diversity and population genetic structure are informed by forest habitat associations and fragmentation. A multi-faceted approach of sampling methods, including capture and acoustic recording, and species identification techniques (morphology, acoustics, and DNA barcoding) were used to assemble an inventory of 25 species, with range extensions noted for six species. The first reference call library of hand released bats for forests in this region is presented, which may be used for species identification in further acoustic surveys. A minimum acoustic monitoring period of 6 to 7 nights per forest is recommended for future surveys. Forest biogeography was an important determinant of the functional diversity of insectivorous bat assemblages. Forest edge effects were found to demonstrate a positive relationship with functional evenness, thus motivating for maintenance and conservation of forest edges, particularly in temperate regions. Larger forearm length and low wing loading were identified as morphological traits exhibiting greater sensitivity to fragmentation, flagging species exhibiting these traits as potentially vulnerable to habitat fragmentation. The effect of historical climate-induced fluctuations of forest extent on population genetic structuring and demographic histories for six species was investigated using two mitochondrial markers, cytochrome b and D-loop. Population genetic trends were not informed by forest habitat associations, but rather by species-specific traits of dispersal ability, philopatry, and roost utilisation. Low genetic diversity and high population structure identify two species, Rhinolophus swinnyi and Laephotis botswanae, for conservation priority. Demographic responses to the Last Glacial Maximum (LGM) were not detected, with all six species displaying population expansions over this time. It appears that volant insectivores in eastern South Africa were less affected by the harsh conditions of the LGM than elsewhere. The dusky pipistrelle (Pipistrellus hesperidus) was used as a model organism to investigate the gene flow, genetic diversity, and migration of a forest-utilising species across the region with the use of eight microsatellite markers. The effects of urbanisation and agricultural development on gene flow were also examined. Findings of low population structure, low migration rates, and two genetic discontinuities were presented. This species does not depict dependence on forested habitats to maintain genetic connectivity on the landscape. The data also suggest that agricultural development and urbanisation have not yet had an impact on gene flow, thus providing a baseline with which to monitor the effects of future anthropic development on this species. Overall, this study has provided novel insights into the taxonomic, functional, and genetic diversity of forest-utilising bats in relation to biogeographical history and fragmentation within eastern South Africa