Aspects of the ecology of three mongoose species along a rural–urban landscape gradient of KwaZulu- Natal, South Africa.
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Date
2020
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Abstract
Many small carnivore species are of particular concern for conservation because of their elusive
behaviour, diminutive size and crepuscular habits. Management and research tend to be
challenging and thus is often limited. Several members of the Herpestidae family fall into this
research dead zone, including the large grey mongoose (Herpestes ichneumon), slender
mongoose (Galerella sanguinea), white-tailed mongoose (Ichneumia albicauda) and marsh or
water mongoose (Atilax paludinosus). The distribution range and other aspects of the ecology
of these and other such species, has remained vague for much of the sub-tropical regions of
southern Africa because of the scarcity of comprehensive data. There is little understanding of
the basic ecology of these mongoose species, and limited progress has been made in
understanding the tolerance of these species within a changing environment. These species of
mongoose appear to persist across KwaZulu-Natal’s (KZN), South Africa, anthropogenically
modified habitats (farmlands and urban). Small carnivore species, such as mongooses, can
provide models of how medium-sized carnivores tolerate differing degrees of anthropogenic
land-use change.
A global review of the current knowledge and research effort for urban mammalian
mesocarnivores was conducted. In the last decade, there has been a dramatic increase in the number
of studies that focus on medium-sized mammalian carnivores. Disproportionate levels of urban
studies exist for mesocarnivores. Several species have been comprehensively studied in the United
States of America and the United Kingdom. These two developed countries held more than half of
all studies on urban mammalian mesocarnivores. Areas of the world that are undergoing rapid
urbanisation have the most significant deficiency of research.
Across Africa, the spatial ecology of the Herpestidae family remains relatively poorly
studied. We investigated how anthropogenic land-use change affects aspects of the ecology of
three co-existing mongoose species (large grey, water and white-tailed) in the agricultural setting of the KZN Midlands. Individuals of these three species of mongooses were trapped,
collared and tracked using GPS-UHF (ultra-high frequency). The results presented show that
the three focal species have different spatial requirements and movements from previous stated
in literature. The natural habitat and farmland mosaic of the KZN Midlands are segregating the
preferred habitats into small fragments. These niche fragments are intensely used by each
species and allow them to co-exist in these anthropogenically modified environments. Besides
these species’ generalist nature, their behavioural plasticity may assist them in persisting in
anthropogenically modified landscapes. In the absence of apex predatory control, an expansion
in the range and population number of Herpestidae species is expected. This study provides
crucial information on the spatio-temporal ecology of large grey, water and white-tailed
mongoose in the KZN Midlands. The spatial movements of the three co-existing species in this
study highlighted the variability that is present at a species and individual level. Further
research is required to address the human–wildlife conflict that takes place locally. The urban
aspect of the large grey, water and white-tailed mongoose ecology is also understudied, and we
recommend further research be targeted.
The spatial ecology of water mongoose in the urban green space matrix of the Upper
Highway Area of eThekwini, KZN, was subsequently investigated. This was to compare
aspects of their ecology between fragmented natural farmland and urban mosaic using similar
methods. Water mongooses occurred at a high density in the fragmented green Durban
Metropolitan Open Space System (D’MOSS). Insight into the spatial ecology of urban water
mongoose (home range, core area utilisation, overlap and habitat use) determined using GPS
telemetry data from 14 water mongooses from July 2018 - October 2019. Water mongooses
had constricted spatial movements that were highly dependent on natural refugia, and
individuals intentionally avoided built-up areas of the urban matrix. The confined nature of
these green spaces consequently resulted in home range sizes that were significantly smaller than their farmland conspecifics. However, the species behavioural plasticity and generalist
nature has allowed the species to occur at higher population densities in the green spaces of the
urban matrix of the Upper Highway Area.
Furthermore, the effects of urban sprawl on the dietary ecology of water mongooses
using faecal analyses was conducted. Water mongooses scat samples (n = 104) were
opportunistically collected and with the aid of members of the Kloof Conservancy during the
study. Urban water mongooses consume a diverse array of dietary items (9 categories), which
is dominated by three categories (relative frequency of occurrence: crustaceans 35.7%,
invertebrates 19.9%, small mammals 19.1% and other 25.2%). Seasonal variation in the diet
only occurred for crustaceans and invertebrates with the other dietary categories consumed
equally throughout the seasons. Additionally, it was demonstrated that urban water mongooses
are supplementing their diets with anthropogenic waste (chicken bones, plastic particulates and
cigarette butts). The broad diversity in dietary categories and supplementation of anthropogenic
waste demonstrates the generalist opportunistic feeding behaviour and adaptability of the
species in an urban matrix.
An online questionnaire survey was conducted to investigate socio-ecological attitudes
and general perspectives towards mammalian mesocarnivores across a land-use gradient
(rural–urban) from the uMgungundlovu to eThekwini Municipalities of KZN. Significant
trends were assessed using the frequency of responses. The public held a range of different
perspectives. Overall, respondents viewed mesocarnivores as non-threatening and vital for the
environment. However, black-backed jackals (Canis mesomelas) were commonly identified as
a problematic pest species, that subsequently are targets of predator control pressures by rural
participants. The survey also identified that smaller, behaviourally flexible species (mongoose
species and cape genet Genetta tigrina) were commonly sighted and are potentially increasing
in both land-use types in the absence of competition and predatory control. Vehicle collisions are the primary cause of mesocarnivore fatality reported by participants of the survey. The
impact of mesocarnivores was perceived differently along a land–use gradient which links to
levels of interaction. The study emphasises the importance of citizen science and community
engagement when attempting to understand the drivers of human–wildlife interactions and
potential mitigation strategies.
The present multifaceted study has improved our understanding of solitary members of
the Herpestidae family and how anthropogenic changes affect them across a land-use gradient.
Furthermore, the behavioural flexibility and adaptability of mongooses in enabling them to
persist at differing degrees of anthropogenic pressure were evident. However, the size class of
mammalian mesocarnivores remains understudied in Africa, and this is of concern in a rapidly
developing region.
Description
Doctoral Degree. University of KwaZulu-Natal, Pietermaritzburg.