Taxonomic, functional, and avian community dynamics in selected Southern Mistbelt Forests of southern KwaZulu-Natal and the Eastern Cape, South Africa.
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Date
2020
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Abstract
Human population increase and landscape transformation result in the reduction of natural
habitats, such as forests, causing changes in forest patch composition, habitat amount, patch
size, isolation, shape, and edges. This is challenging specialist such as Orange Ground-thrush
(Geokichla gurneyi) and Lemon Dove (Aplopelia larvata) species unable to survive in
fragmented habitats and also influencing the composition and distribution of avian species
assemblages. Therefore, the main aims of this multifaceted study were to (1) assess the habitat
requirements of two forest specialised bird species, the Orange Ground-thrush (Geokichla
gurneyi) and the Lemon Dove (Aplopelia larvata); (2) identify if avian assemblage diversity
and species functional trait diversity show consist patterning across different landscapes in a
forest ecosystem; (3) determine the influence of vegetation structures on the taxonomic and
functional diversity of avian forest species, and (4) modelling how to connect forest patches of
higher functional diversity. In 2018-2019, we conducted a series of camera-trap surveys of 21-
day periods and fixed-radius point-count surveys at 420 sites across 94 forest patches of
Southern Mistbelt Forest of southern KwaZulu-Natal and Eastern Cape, South Africa, during
the breeding and non-breeding seasons in conjunction with surveys of microhabitat structural
covariates. Firstly, we modelled the probability of occupancy and detection for the selected
two species, which showed that forest specialist species prefer a highly diverse habitat
structure. Secondly, we quantified functional diversity measures based on species’ trait per
patch to measure the influence of habitat and landscape configuration on each measure. This
resulted in functional diversity measures which were highly influenced by patch size, the
distance between patches and diverse landscape and habitat. Thirdly, we conducted RLQ
analyses to examine the association between avian functional traits and microhabitat structures
present at each forest patch.We found there was a significant difference in vegetation structure
and species richness between forest patches. Lastly, we ranked the functional diversity measures scores of avian communities present at each forest patch to identify core habitat
patches responsible for the contribution of high functional diversity measures. Protection of
natural forest habitat and diverse landscapes is important in preserving avian communities.
Description
Doctoral Degree. University of KwaZulu-Natal, Pietermaritzburg.