Doctoral Degrees (Ecology)

Permanent URI for this collectionhttps://hdl.handle.net/10413/7487

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Anthropogenic impacts on forest mammals in the Southern Mistbelt Forests in the Midlands of KwaZulu-Natal, South Africa.
(2023) Cordier, Craig Paul.; Downs, Colleen Thelma.; Ehlers Smith, David Alan.; Ehlers Smith, Yvette Cathrine.
Habitat loss worldwide is a major threat to biodiversity. Forest loss is affected by numerous factors, including natural climate change and anthropogenic disturbances (e.g., logging, habitat conversion or increased fire activity). Forest fragmentation results in reduced patch sizes, increased edge effects, and connectivity between patches negatively impacted. Forest fragmentation effects on species differ, with some considerably more sensitive to these changes than others, often resulting in their local extinction. By monitoring biodiversity, effective conservation measures can be implemented to conserve the biodiversity in these forests. Remote camera traps have become an increasingly popular tool to study wildlife in a reliable, non-invasive way. Firstly, the use of camera traps as a research tool in Africa using a systematic review was determined. This highlighted the countries with studies that used camera traps the most, as well as determined the terrestrial wildlife and habitat types receiving the most focus. The findings from assessing camera trap research in Africa revealed that most studies were conducted in South Africa, with most studies focusing on the occupancy of mammals, with a particular focus being on large carnivores, the majority of which were leopard Panthera pardus. Most studies were conducted in forests, followed by savannah/bushveld. Secondly, the presence of forest mammalian species was assessed in the Southern Mistbelt forests in the Midlands of KwaZulu-Natal, South Africa. These forests are fragmented because of both natural and anthropogenic factors. An extensive camera trapping survey was conducted between October 2020 and April 2021 (wet season), and between May 2021 and September 2021 (dry season), with 14 indigenous forest patches being sampled. A total of 339 camera trap stations were deployed in this study, with microhabitat conditions, in a 20 m radius around each camera trap, collected to determine their impact on bushbuck Tragelaphus scriptus, a diurnal forest specialist, and Cape porcupine Hystrix africaeaustralis, a nocturnal generalist, and how the microhabitat conditions potentially impacted their occupancy between the austral wet and dry seasons. Bushbuck were the most recorded mammalian species recorded during both seasons. Cape porcupine presence was recorded more during the dry season, with various microhabitat variables influencing their occupancy. Cape porcupines, as generalists, likely use the forest food resources during the dry season. Bushbuck presence was lower in state-owned forests, likely because of the hunting activities observed in these forests. Thirdly, data collected from the camera trapping surveys were used to determine the influence of landscape factors, including patch size, landscape configuration (number of neighbouring patches), and patch isolation (distance from mainland patch), on forest mammalian species diversity in forest patches, between the wet and dry seasons. Patch size strongly influenced forest mammalian species richness, which was relatively low, with more species occupying larger patches than smaller patches. Similarly, landscape configuration affected species richness and was generally higher in those forests surrounded by multiple forest patches. Forest isolation, however, did not seem to be particularly impactful in determining forest mammalian species diversity. Overall, this research showed the value of camera traps as a research tool and their effectiveness in studying rare and elusive mammalian species in Africa. Effects of anthropogenic disturbances on various forest mammalian species were highlighted, with activities such as hunting and uncontrolled resource harvesting, such as collection of fuelwood, medicinal plants and building materials by the local communities, impacting the presence of various forest mammalian species, particularly forest specialist species, such as the blue duiker Philantomba monticola. The importance of maintaining small forest patches, often considered of low conservation value, was highlighted. These act as essential ‘stepping stones’ between forest patches, allowing species to traverse a landscape mosaic. The need for conservation measures not to disregard the importance of these small forest patches is emphasised, as they are vital assets to maintain species richness in landscape mosaics with forest patches.
Aspects of common hippopotamus (Hippopotamus amphibius) behavioural ecology and their consequences in managed systems in South Africa.
(2020) Fritsch, Camille Jacques-Armand.; Downs, Colleen Thelma.
Abstract available in PDF.
Aspects of monitoring wild and captive Nile crocodile (Crocodylus niloticus) populations in southern Africa = Izingxenye zokubhekelela uhlobo lwengwenya yasendle nevalelwe yaseNile (Crocodylus niloticus) e-Afrikha eseningizimu.
(2021) Myburgh, Hendrik Albert.; Downs, Colleen Thelma.
As biodiversity across the globe declines because of anthropogenic activities, the need for conservation efforts increases. For conservation efforts to be successful, it is imperative that detailed information about species and their populations; size and status within and outside of protected areas be collected. In freshwater systems, crocodile population demographics can provide an integrated view of ecosystem state, but the habitat and cryptic nature of crocodilians confound the derivation of population demographics for the taxa. Crocodile populations were historically monitored by fixed-wing aircraft, helicopter or limited spotlight surveys in those areas that are navigable by boat. These techniques are costly and labour-intensive; require specialised personnel and equipment, and are subject to observer bias and low accuracy in size class estimations. Furthermore, they produce population demographic data that is not verifiable as they rely on decisions and opinions of observers in the moment of surveying, often fromfast-moving platforms. Lately, unmanned aerial vehicle (UAV) techniques have been shown to accurately and effectively count crocodiles, but they still require costly software and hardware packages. In this study, low-cost, open-source UAV techniques were developed as an alternative method to monitor and survey crocodilians, particularly Nile crocodiles (Crocodylus niloticus), both in captivity and in the wild. In South Africa, Nile crocodiles occur in open bedrock systems with relatively little riparian vegetation, an ideal scenario for the application of UAVs. The possibility of improved population demographic data for wild Nile crocodile populations by converting size data derived from UAVs to age data was explored by radiocarbon dating Nile crocodile claws. Morphometric correction factors applicable to UAV census are derived, and a fixed-wing survey is compared with a commercial-grade UAV survey of wild Nile crocodile populations in the Kruger National Park. The limitations and applicability of these approaches for crocodilian and other ecological studies were assessed. Their future applications in ecology and management are proposed. Iqoqa Njengoba impiliswanomvelo kuwo wonke umhlaba yehla ngenxa yezenzo ezidalwe ngabantu, isidingo sokongiwa kwemvelo siyakhula. Ukuze imizamo yokongiwa kwemvelo ibe impumelelo, kuyaphoqa ukuthi kuqoqwe ulwazi olunzulu mayelana nokuphilayo kanye nezinhlobo zakho, ubungako kanye nesigaba phakathi kanye nangaphandle kwezindawo ezivikelwe. Emanzini aphilayo, uhlobo lwemiphakathi yezingwenya zingasinika iso eliyinhlanganisela lesimo sohlalonhlaliswano yokuphilayo nokungaphili, kodwa isimo sendawo yokuhlala kanye nesingachazeki sididisa ukwehlukanisa ukutholakala komphakathi wezinhlobo zezingwenya. Imiphakathi yezingwenya yayibhekelelwa emandulo ngendizamshini ehlala phezulu emoyeni, indiza enophephela emhlane noma amasaveyi angemaningi agqamile kulezo zindawo okuhambekayo kuzo ngezikebhe. Lawa masu ayabiza futhi adinga amandla okusebenza, adinga abasebenzi abaqondene kanye nemishini yokusebenza, kanti futhi ancike ekuchemeni kobukelayo kanye nezinga eliphansi ngobungako besihlawumbiselo sohlobo. Okunye futhi, akhiqiza imininingo yohlobo lwemiphakathi engathembakali njengoba ethembele ezinqumeni kanye nemibono yababukela ngesikhathi sokwenza amasaveyi, okujwayele ukuthi kube izinhlaka ezihamba ngokushesha. Kamumva nje, amasu esithuthi ezingasetshenziswa muntu ezisemoyeni, i-unmanned aerial vehicle (UAV) asevezwe njengakhombisa ukubalwa kwezingwenya okuqondile nokunemiphumela emihle, kodwa asadinga ubuchwepheshe obubizayo kanye nezindodla zobuxhaxhaxha bobuchwepheshe. Kulolu cwaningo, okungabizi, amasu ezizinda ezivulekile e-UAV kwaqanjwa njengenye yendlela engasetshenziswa ukubhekelela nokusaveya izingwenya, kakhulukazi izingwenya zaseNile (Crocodylus niloticus), zozimbili ezivalelwe kanye nezasendle. ENingizimu Afrikha, izingwenya zaseNile zivela ekusetshenzisweni kwamadwalamsuka avulekile anotshalovikelo olungeluningi, okuyisibonelo esincomekayo sokusebenzisa ama-UAV. Ukuba khona kwemininingo ethuthukile yezinhlobo zemiphakathi yezingwenya zasendle zeNile ngokushintsha ubungako bemininingo etholakale kuma-UAV ukukhulisa imininingo kwaphenywa ngekhabhoni yomoya ukubona izindlawu zengwenya yaseNile. Izimo zokulungisa ukusebenza kokubala kwe-UAV kutholakele, kanti futhi isaveyi yophiko olunganyakazi luqhathaniswa nesaveyi ye-UAV yohlobo lokusebenza lwemiphakathi yohlobo lwengwenya yasendle yaseNile e-Kruger National Park. Imikhawuko kanye nokusebenzeka kwalezi zindlela zokubhekelela izingwenya kanye nezinye izicwaningo zezemvelo kwahlolwa. Ukusebenza kwayo kwesikhathi esizayo emvelweni kanye nokwenganyelwa kuyaphakanyiswa.
Aspects of the ecology and persistence of vervet monkeys in mosaic urban landscapes in KwaZulu-Natal, South Africa = Izingxenyezici zendawomvelompiliswano kanye nokwanda kwezinkawu zohlobo lwe-vervet ezindaweni zasemadolobheni ezihlukahlukene ngokwezimo zempilo KwaZulu-Natali eNingizimu Afrika.
(2022) Pillay, Kerushka Robyn.; Downs, Colleen Thelma.
The geological era in which we live is termed the Anthropocene and is causing the greatest loss of biodiversity and species brought on by a single species: Homo sapiens. The human population places great demands on the environment, altering and modifying it to suit people’s needs. Urbanisation is one of the greatest anthropogenic land-use modifications, predominantly for infrastructure and housing developments. This results in the loss of natural green spaces where wildlife lives, forcing them into smaller fragmented habitats, often having to share the urban mosaic landscape with humans. These increased interactions often lead to humanwildlife conflict. Generally, urbanisation affects species negatively. However, some species exhibit the ability to persist in urban areas, successfully utilising resources for their natural life traits. One such primate species persisting in urban mosaic landscapes is the vervet monkey, Chlorocebus pygerythrus, particularly in the eThekwini Municipality, Durban, KwaZulu-Natal Province, South Africa. Increased human population growth and associated urban transformation have increased contact between humans and troops of vervet monkeys using residential and industrial gardens. This has led to increased human-wildlife conflict, with vervet monkeys often persecuted because of their damage to human property and harassment. Little is known about the ecology of urban vervet monkeys, so to assess and manage this wildlife conflict, a need to determine the behavioural ecology and persistence of vervet monkeys were investigated in this study. This study analysed vervet monkeys' spatial ecology in the mosaic urban-forest landscape and provided insight into their home ranges and habitat use here. Additionally, the effects of anthropogenic activities and human-wildlife conflict on wild vervet monkeys were documented. The results contribute to understanding the foundation of human-vervet conflict resolution programmes and support for further education and coexistence with wildlife in mosaic urban landscapes. The conservation of vervet monkeys should be supported by all who live in these areas, not by some factions. The presence of primates, such as the vervet monkey, that use managed green spaces, such as gardens, in the eThekwini Municipality should provide the public with the ultimate catalyst and insight into protecting and conserving this species and others for future generations. Overall, the results presented in this thesis provide an understanding of the persistence of this Old World primate in mosaic urban landscapes. Iqoqa Isikhathi esiphila kuso mayelana nesimo sendalo yomhlaba esikuwo saziwa ngele-Anthropocene siyimbangela yokushabalala okusezingeni eliphezulu yokusatshalaliswa kwendawomvelompiliswano kanye nohlobo lwezilwane okubangelwa uhlobo olulodwa: oluyi-Homo sapiens. Izidalwa ezingabantu zinomthelela omkhulu emvelweni ngendlela yokuthi ziguquguqula imvelo ukuze kufezeke izidingo zazo. Ukwakhiwa kwezindawo zasemadolobheni kungenye yezinguquko ezidalwa ngabantu lapho besebenzisa umhlaba ikakhulukazi ukwakha izindawo zokuhlala kanye nezingqalasizinda. Lokhu kuholela ekuthini kuntuleke izindawo okuphila kuzo izilwane zasendle okube sekudala ukuthi lezi zilwane zigcine sezihlala ezindaweni ezimpintshekile zaba zincane. Lokhu kube sekuholela ekuthini zigcine sezibanga indawo nabantu basemadolobheni. Lokhu kwanda kokuhlalisana nabantu kuholela ekushayisaneni phakathi kwabantu kanye nezilwane. Nokho-ke, kunohlobo olukhombisa ukuthi luyakwazi ukuqhubeka nokuphila kahle ezindaweni ezingamadolobha ngokuzizamela kulokho okukhona ukuze luziphilise ngendlela efanele. Uhlobo olukhombise ukuthi luyakwazi ukuqhubeka nokuziphilisa ngaphansi kwesimo sasemadolobheni yilolu lwezinkawu ezaziwa nge-vervet, Chlorocebus pygerythrus,ikakhulukazi endaweni kaMasipala weTheku, eThekwini, esifundazweni saKwaZulu-Natali, eNingizimu Afrika. Ukwanda kwesibalo sabantu kanye nokuguquka kwesimo senhlalo yabantu okuhambisana nakho sekwenze ukuthi kwande nokuhlangana kwabantu nemihlambi yezinkawu ezizitika ezingadini zabantu emakhaya kanye nasezingadini zabalimi abakhulu. Lokhu sekuholele ekushayisaneni phakathi kwabantu kanye nezilwane zasendle okwenza ukuthi izinkawu ezingama-vervet zizithole zisenkingeni ngenxa yokucekela kwazo phansi impahla yabantu kanye nokuba yisicefe esingapheli. Aluluningi ulwazi olukhona mayelana nezinkawu zasemadolobheni ezingama-vervet, ngakho-ke lolu cwaningo lwaphenya mayelana nokuziphatha kwalezi zinkawu ngaphansi kwezimo zendawo eseziguqukile kanye nokwanda kwazo ukuze kuhlolwe kuphinde kulawulwe lokhu kushayisana nezilwane zasendle. Lolu cwaningo lwahlaziya izindawo ezingamahlathi asedolobheni okuhlala kuzo lezi zinkawu ezingama-vervet, lwase lunikeza ulwazi olujulile mayelana nezindawo okuhlala kuzo lezi zinkawu kanye nendlela eziziphilisa ngayo kulezi zindawo. Okunye okwaqoshwa phansi yimithelela yezinto ezenziwa ngabantu kanye nokushayisana phakathi kwabantu kanye nezinkawu ezingama-vervet. Imiphumela yocwaningo yathasisela olwazini olumaqondana nezinhlelo okungakhelwa phezu kwazo ukuxazululwa kokushayisana kwabantu nezinkawu ezingama-vervet, iphinde isekele ukufunda okuqhubekayo mayelana nokuhlalisana nezilwane zasendle ezindaweni ezisakhula zasemadolobheni. Kumele kusekelwe ukongiwa kwezinkawu ezingama-vervet yibo bonke abahlala ezindaweni ezisemadolobheni, kungabi ngabathile kuphela. Ukuba khona kwalolu hlobo lwezilwane ezifana nezinkawu ezingama-vervet ezindaweni ezisetshenziswa nezenganyelwe njengezingadi zomphakathi njengezikaMasipala weTheku kumele kuhlomise amalungu omphakathi ngolwazi nanogqozi lokuvikela kanye nokonga lolu hlobo lwezilwane kanye nezinye izinhlobo ukuze nezizukulwane ezizayo zikwazi ukuzibona ziphila. Ekugcineni kwakho konke imiphumela etholakale kulolu cwaningo iveze ulwazi nokuqonda mayelana nokwanda kwalolu hlobo lwezinkawu ezindaweni ezingamadolobha.
Aspects of the ecology of African woolly-necked storks (Ciconia microscelis) in an anthropogenic changing landscape in KwaZulu-Natal, South Africa.
(2018) Thabethe, Vuyisile.; Downs, Colleen Thelma.
Urbanisation is the fastest-growing forms of anthropogenic land use change and a major threat to biodiversity worldwide. However, despite the negative impacts of urbanisation on native species, some species persist in urbanised environments and this thesis aimed to examine one such species, the African woolly-necked stork (Ciconia microscelis). African woolly-necked storks have recently colonised urbanised environments in KwaZulu-Natal, South Africa, and are now common in suburban areas in particular. Despite its proximity to human settlements and recent high abundance in suburban areas, knowledge of the African woolly-necked stork remains poorly documented in South Africa. Therefore, this thesis aimed to investigate the aspects of ecology of African woolly-necked storks within the suburban landscape to determine what factors facilitate their ability to persist in these environments. Firstly, I assessed the long-term trends in occupancy, colonisation and extinction of African woolly-necked storks as a function of change in land cover across KwaZulu-Natal Province, South Africa. This was accomplished by applying dynamic occupancy models to Counts in South Africa. African woolly-necked stork wetland occupancy was relatively stable (ψ = 0.37-0.39) across years. However, they rapidly extended their distribution range to urbanised environments, becoming common in man-made wetlands. Overall, this study found that the increased area of anthropogenic areas led to an increase in the probability of wetland colonisation by African woolly-necked storks. Secondly, I investigated the foraging opportunities that might be responsible for the recent colonisation of urbanised environment by African woolly-necked storks. I found that a significant number of householders (71%) deliberately fed African woolly-necked storks daily throughout the year and the majority provided meat while others fed inappropriate food such as bread. Furthermore, I found that, African woolly-necked storks were relatively habituated in urban areas of KwaZulu-Natal, with some even feeding from hand and others going inside homes to find the supplemental food. These results showed that the African woolly-necked stork is successfully utilising and exploiting anthropogenic food – a novel behaviour for this species. Thirdly, given that the selection of appropriate nest sites has major implications on reproduction success and survival of urban bird species, I was interested to determine if African woolly-necked storks bred in urbanised areas and, if so, which features of the nest site and surrounding habitat influenced their occupancy. I found 30 African woolly-necked stork nests in suburban areas of KwaZulu-Natal. African woolly-necked storks have successfully established breeding sites in suburban areas (mostly in domestic gardens), especially near swimming pools, while exotic pine (Pinus elliottii) and eucalyptus (Eucalyptus spp.) trees were the most preferred trees. Anthropogenic structures were also used as nesting sites suggesting a nesting behaviour shift. Lastly, after acquiring evidence that African woolly-necked storks successfully utilise anthropogenic food and have established a breeding population in urban areas, I was interested to know what food they provisioned to their nestlings. Furthermore, I investigated the breeding behaviour of African woolly-necked storks using direct observations and infrared camera traps during three breeding seasons (2015-2017). Although anthropogenic food was provided to nestlings, African woolly-necked storks provisioned their nestlings predominantly with natural food, primarily amphibians, particularly guttural toads (Amietophrynus gutturalis). African woolly-necked storks consistently reoccupied most nest sites across study years since initial discovery, suggesting that this population was at least stable. For the first time, I documented evidence of cooperative breeding where more than two adults provided care to a single nest. (Amietophrynus gutturalis). African woolly-necked storks consistently reoccupied most nest sites across study years since initial discovery, suggesting that this population was at least stable. For the first time, I documented evidence of cooperative breeding where more than two adults provided care to a single nest.
Aspects of the ecology of three mongoose species along a rural–urban landscape gradient of KwaZulu- Natal, South Africa.
(2020) Streicher, Jarryd Peter.; Downs, Colleen Thelma.; Ramesh, Tharmalingam.
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.
Aspects of the ecology of trumpeter hornbill (bycanistes bucinator) across urban-forest mosaics in KwaZulu-Natal, South Africa.
(2016) Chibesa, Moses.; Downs, Colleen Thelma.
Abstract available in PDF file.
Aspects of the use of vultures in traditional medicine in KwaZulu-Natal, South Africa, and conservation implications.
(2022) Manqele, Nomthandazo Samantha.; Downs, Colleen Thelma.; Selier, Sarah Anne Jeanneta.
Eighty percent of people in developing countries use traditional medicine either as a primary source of healthcare or as supplementary to western medicine. Traditional medicines are mainly derived from wild plants and animals. There has been a marked global increase in the use of animals and their body parts as ingredients in traditional medicine. The harvesting and use of wildlife resources in traditional medicine are largely unregulated and involve many species of conservation concern. This is true for African vultures, as evidence indicates that traditional medicine is responsible for 29% of African vulture mortalities. Currently, six out of seven vulture species in South Africa face a serious threat of extinction. The threatened species are listed under the Threatened or Protected Species regulations, which prohibit hunting and consumption. However, evidence suggests a long-standing use of vultures in traditional medicine in KwaZulu- Natal, South Africa, yet so much remains unknown about this practice. Understanding the belief system and the socio-economic dispositions underpinning the belief-based use of vultures will favour vulture conservation efforts in the province. Research was undertaken with the aim of advancing the knowledge base regarding the use of vultures in traditional medicine in KwaZulu-Natal. Accordingly, the following objectives were established: 1) to assess human-vulture interactions in a dynamic ecosystem, 2) to evaluate the dynamics behind the illegal harvesting and trade of vultures and their body parts, 3) to investigate the ethnomedicinal use of vultures by traditional health practitioners and 4) report on the efficacy of religion as an alternative for traditional medicine use. The study involved local communities surrounding protected areas and specific groups such as hunters, muthi traders, and traditional healers. A mixed-methodology approach was adopted, and data were collected using questionnaire surveys, in-depth interviews, focus group discussions and observations. A total of 728 respondents contributed to this study. Local people’s perceptions towards vultures were predominantly positive. Respondents appreciated vultures for removing carcases, thus keeping the environment clean. Results also demonstrated that hunting and wildlife consumption were common in the study areas, and that the hunting and use of vultures were a part of this. Vultures were harvested from protected areas and sold directly to traditional healers and also to muthi traders. Vultures were reportedly important in traditional medicine, but their harvesting was limited because it was perceived as a criminal activity, and the birds reportedly occurred in smaller numbers than before. In traditional medicine, seven vulture parts were used, but the head treated the majority (62%) of ailments reported. Seventy-one percent of the uses for vulture-based remedies were spiritual in nature. Religious practices such as church attendance, prayer and fasting, coupled with products like holy water, can provide relief from physical and psychological ailments. In this study, the role of religion in contributing positively to human health and well-being was underscored. Overall, results from this study can be instrumental in guiding efforts to improve vulture conservation in KwaZulu-Natal and other parts of South Africa.
Assessing anthropogenic impacts on the persistence of forest mammals within the Indian Ocean coastal belt of southern KwaZulu-Natal province.
(2016) Ehlers Smith, Yvette Cathrine.; Downs, Colleen Thelma.
Abstract available in PDF file.
Building a conservation strategy for the harpy eagle in the Amazon Forest.
(2020) Pereira de Miranda, Everton Bernardo.; Downs, Colleen Thelma.; Peres, Carlos Augusto.
Apex predators are threatened worldwide and are considered a priority in the conservation biology agenda. Their decline is associated with habitat loss and degradation, and persecution arising from perceived and actual conflict with humans. The trophic cascades emerging from the loss of apex predators can disrupt the regulation of prey populations, seed dispersal, tree composition and nutrient cycles derived from carcass deposition, with widespread consequences for biodiversity. The harpy eagle (Harpia harpyja) is the Earth's largest eagle and is considered a flagship species for Amazon Forest conservation. Harpy eagles are threatened by poaching and by loss and degradation of habitat. This thesis is comprised of nine chapters—being seven of them data chapters—related to harpy eagle biology and conservation. Chapters 1 and 9 are respectively an introduction and a synthesis about the subjects I approached. In Chapter 2, I created a predictive model of the species range aimed at understanding the current distribution, the contraction of the species distribution compared with the original range, and sites that currently have notable potential for reintroduction of harpy eagles. In Chapter 3, I analyse the effects of environmental parameters such as moonlight and temperature on prey selection probability. In Chapter 4, I aimed to establish the factors that drive the killing of harpy eagles by local people, including the relation between livestock predation and harpy killing. Chapter 5, I explore the nesting, timing and rates of visitation to nests by parent and fledged eagles as it relates to the viability of harpy nests as ecotourism attractions. In Chapter 6, I conducted a meta-analysis that synthesises data on nest tree selection by harpy eagles with the tree species preferences by loggers. In Chapter 7, I test the hypothesis that harpy eagles are agents of accumulation of nutrients, by concentrating decaying remains of prey items at nest sites over decades, thereby biomagnifying soil and foliage nutrient profiles. In Chapter 8, I describe rates of prey delivery by harpy eagles to their nests, and the composition of this prey, to understand the effects of forest loss on harpy eagle feeding ecology. This multi-faceted set of topics were combined in the field with a new, responsible ecotourism strategy focused on harpy eagles. Subsequently, I hope to build an evidence-based, economically-viable conservation strategy for the largest eagle on Earth, as well as to understand their keystone function of harpy eagles in Neotropical forest ecosystems.
The conservation ecology of the African tigerfish Hydrocynus vittatus in the Kavango River, Namibia.
(2017) Jacobs, Francois Jakob.; Downs, Colleen Thelma.
Abstract available in PDF file.
The ecology and conservation biology of Lilian's lovebird Agapornis lilianae in Malawi.
(2014) Mzumara, Tiwonge I.; Downs, Colleen Thelma.
Despite their popularity, parrots are the world’s most threatened birds. Lovebirds (Agapornis) are very popular pet and aviary birds and as ecologically specialised species in the wild, they are also among the most threatened group of birds. Lilian’s lovebird Agapornis lilianae is a mopane Colophospermum mopane woodland specialist. This study represents the first detailed investigation of the species ecology in the wild. The current distribution of Lilian’s lovebird in Malawi was explored. Furthermore, the extent of the largest resident population in Liwonde National Park (LNP) was investigated. Five new atlas records are reported; three within 40-56 km of the LNP population, and two were over 150 km south and north of LNP respectively. One of them in Kasungu National Park is about 66 km from the Lilian’s lovebird population in Luangwa Valley, Zambia. Lilian’s lovebirds occurred throughout LNP with the highest abundance in the central section. Seasonal movements to areas outside the park were recorded. A variety of vegetation types were used by the lovebirds. The strongest vegetation associations were with seasonally wet grasslands and not mopane woodlands. The abundance and density of the Lilian’s lovebird in LNP was investigated. The highest density estimates of 17 ± 4.8 lovebirds km-2 were recorded in LNP’s mopane woodland. However, number of observations per transect differed significantly. Waterhole counts had the lowest estimates (10 ± 3.5 lovebirds). Flyway counts had the intermediate estimate (14 ± 3.0 lovebirds). The total population of Lilian’s lovebirds in LNP is therefore estimated to be about 4000 individuals. The use of line transect counts at the end of the rainy season is recommended for continued monitoring of Lilian’s lovebirds abundance in LNP. Lilian’s lovebird is a secondary cavity user adapted to mopane woodlands. We investigated its roost characteristics and roosting behaviour. We quantified tree and roost site variables for roost and non-roost trees. Roosting behaviour was observed during the morning and late afternoon. Lilian’s lovebirds’ roosts were located in large tall mopane trees with a mean diameter at breast height (dbh) of 57.4 ± 1.64 m, a mean height of 16.5 ± 0.42 m, and with a mean cavity height of 10.0 ± 0.05 m. All roosts were located in mopane trees within mopane woodland with 10 – 50 % tree cover. Non-roost areas had significantly smaller trees (mean dbh = 39.4 ± 1.72 m) and were located significantly closer together. Human disturbance was low in both areas, however, evidence of elephant Loxodonta africana browsing was high with large areas of stunted mopane woodland recorded in non-roost areas. We recommend that the current LNP vegetation map be updated to highlight areas of stunted mopane woodland unsuitable for Lilian’s lovebird roosts. The impact of elephant browsing on large mopane trees should be assessed to understand its impact on the availability of suitable cavities for lovebirds and other tree cavity-reliant vertebrate species. Investigations into the diet and foraging behaviour of the Lilian’s lovebird revealed they fed on 30 different plant species. These occurred in six habitat types, two of which were outside LNP (agriculture fields and dambos). In the wet season majority of Lilian’s lovebirds (23 %) foraged in dambo areas, whilst in the dry season (August – November) the lovebirds mainly foraged in grasslands with tree cover (18 %). In mopane woodland feeding flock sizes differed significantly between the wet (mean = 20 ± 1.0 lovebirds) and dry season (mean = 34 ± 2.3 lovebirds). Grass seeds were their main food source from December to June. Lilian’s lovebirds diet was more diverse from July to November and included leaves, leaf buds, fruits, fruit seeds and herbs. Grass seeds fed on during the wet season had a high protein and energy content. The Lilian’s lovebirds foraging habitat is protected within LNP, however, early burning in areas outside the park needs to be monitored. The breeding biology of the Lilian’s lovebird was investigated. Data were collected through a combination of direct observations and infrared camera traps during three breeding seasons. Results show large similarities with the black-cheeked lovebird A. nigrigens in Zambia. The breeding season was from February to May. Lilian’s lovebirds nested mainly in south-east oriented deep cavities (≥ 1 m) located in large mopane trees (mean dbh = 57.6 ± 2.35 cm). Nests were located in loose clusters in the areas they roosted (mean distance to nearest nest = 24.2 m). Nest fidelity was observed. Clutch size ranged from 3 – 6 eggs, (mean 5.0 ± 0.22). We recorded 49 % hatching success and 69 % fledging success. Results suggest a low breeding success mainly due to the loss of eggs to predation. The use of poison to kill wildlife is a threat to biodiversity. In LNP illegal hunters poison naturally occurring waterholes to catch mammals and birds for food. Lilian’s lovebirds are among the victims at these poisoned waterholes. Lilian’s lovebird population in LNP represents about 20 % of the global population. The drinking habits of the Lilian’s lovebird, the availability of natural waterholes and the occurrence of poisoning incidents in LNP were investigated. Results showed Lilian’s lovebirds congregate at waterholes in the dry season with flock sizes ranging from 1 to 100 individuals. Significantly larger flock sizes were seen in the dry season compared with the wet season. The number of poisoning incidents/year ranged from 1 to 8. The dry season had the highest numbers of poisoning incidents. Lilian’s lovebirds were killed at approximately four poisoning incidents each year between 2000 and 2012. The number of lovebirds found dead at a poisoned pool ranged from 5 to 50 individuals. A list of other species affected by the poisoning is provided. There is need for increased efforts in preventing this lethal activity in the park. Avian diseases are considered to be one of the key threats to bird conservation. Psittacine beak and feather disease (PBFD) is the most significant infectious disease in psittacines. It is caused by the beak and feather disease virus (BFDV) and currently has no cure. PBFD threatens the survival of wild populations of endangered parrots in Africa. The occurrence of BFDV was investigated in wild populations of Lilian’s lovebird. In addition, evidence of blood parasites presence was also investigated to determine their general health. All samples (n = 48) tested negative for BFDV. Blood parasites were observed in 13 of the 48 samples (27 %). Investigation of virus occurrence in other known populations of the species is recommended to assess the conservation risk faced. Lilian’s lovebirds (n = 55) were mist-netted and ringed in LNP. Measurements showed that females were significantly larger than males. About 50 % of the birds ringed in October were half way through their primary moult indicating that moulting starts in earlier months possibly just after the breeding season in April. This study highlights three of the key threats (waterhole poisoning, habitat loss and predation) to the conservation of Lilian’s lovebirds in LNP and provides proposed actions to address these threats.
The ecology of large-spotted genets within an urban landscape.
(2015) Widdows, Craig David.; Downs, Colleen Thelma.
Urbanization is one of the most damaging and rapidly expanding forms of anthropogenic landscape modification and is having profound consequences on biodiversity worldwide. The global increase in urbanization has resulted in exclusion of many carnivore species from human-altered landscapes due to a variety of anthropogenic impacts. However, despite the negative impacts of urbanization on carnivores, certain species such as large-spotted genets (Genetta tigrina) exhibit an ability to persist within urban areas. Despite their extensive distribution range, large-spotted genets are poorly studied in comparison to other African carnivores, with a handful of studies conducted on genetics, activity patterns and diet. Furthermore, no studies have focused on their ecology in an urban environment. There have been increasing reports of large-spotted genets within urban areas throughout KwaZulu-Natal, South Africa. The mosaic of patches of native vegetation within this urban landscape provides habitats for a variety of wildlife species. The main aim of the study was to investigate the ecology of large-spotted genets within an urban landscape and to determine what factors facilitate their ability to persist in an urban environment. Residential interviews were conducted to ascertain information pertaining to behavioural observations, land use as well as wildlife conflict and public perceptions of genets. Chi-square (x2) goodness-of-fit tests were used to determine significant differences in the frequency of responses. Domestic pet food was the main food item genets were observed eating. The most cited cause of genet fatalities were attacks by domestic animals and collisions with vehicles. Genets were reported using roof spaces for resting during daylight hours and as locales for breeding. The majority of respondents expressed positive attitudes towards genets in urban areas; negative views stemmed from concerns of disease transfer and impacts on wild bird populations. We investigated the relationship between occurrence of large-spotted genets with various environmental variables believed to influence their site occupancy and detection in an urban environment. Presence/absence data was collected from 28 camera trap stations between June 2012 and October 2013 in Kloof, KwaZulu-Natal, South Africa. Average estimated occupancy of urban genets was 0.62 ± 0.14 with a detection probability 0.19 ± 0.03. Model selection indicated that bush cover and placement of camera traps on wide paths negatively influenced large-spotted genet occupancy. Both winter and fringe habitats influenced the site occupancy of large-spotted genets positively. Furthermore, bush cover was negatively associated with detection probability of urban genets. The dietary composition and the influence of predictable feeding stations on urban large-spotted genets were investigated through scat analysis. Scats were collected on a monthly basis over a year from eleven midden sites. Invertebrates were the dominant prey items consumed with small mammals also forming an important component of the diet. Significant seasonal variation was recorded with the presence of birds and pollution in the scats with highest recorded frequencies during spring and winter respectively. During winter, when invertebrate abundance declined, urban genets increased their intake of anthropogenic refuse resulting in plastic, elastic bands and various other waste products present in the scats. We investigated the effect of anthropogenic structures on the roost temperatures of large-spotted genets. Roost temperatures were recorded using i-Button® temperature loggers at known genet roosts in anthropogenic structures as well as in natural roost sites (tree hollows and rocky overhangs). Over the seasons temperatures varied significantly between months and among different roosts. However, anthropogenic roost temperatures were significantly higher than ambient temperatures throughout the study period. Furthermore, anthropogenic roosts had higher temperatures (with lower variability) than natural roost sites. This study indicated the importance of anthropogenic structures as daytime roosts and for breeding for large-spotted genets within an urban matrix. Given their adaptability and apparent success within the urban environment, we investigated the movement ecology of large-spotted genets within the urban landscape. Large-spotted genets were captured and fitted with global positioning system mobile transmitters. Although seven individuals were trapped, detailed data were only obtained for two individuals. Minimum convex polygons (MCPs), 95% and 50% kernel density estimates (KDEs) were calculated for a male and female large-spotted genet. The 95% kernel density home range sizes showed relatively small home range sized for both individuals, with an area of 48.2 ha (female) and 17.5 ha (male). Habitat selection within home ranges indicated that the male large-spotted genet preferred urban residential habitat while the female genet avoided nearby croplands. Both individuals used most of the habitats within their study area. Variable habitat used by both individuals in this study confirmed the species’ ability to adapt to the urban mosaic of habitats. This thesis showed the importance of a variety of factors on the distribution of large-spotted genets in landscapes where natural habitats are threatened by changing land use and increasing human populations. Furthermore, this thesis illustrated the ability of genets to live in an urban mosaic landscape by using a variety of anthropogenic resources.
Effects of land-use changes on the distribution and use of Ficus species by frugivores in the urban mosaic landscape of Durban, KwaZulu-Natal, South Africa.
(2021) Raji, Islamiat Abidemi.; Downs, Colleen Thelma.
Land-use change is one of the greatest threats to biodiversity. Over the years, these changes potentially reduced ecosystems capacity to sustain food production for vertebrates. Ficus (figs; Moraceae) is one of the largest plant genera in lowland tropical rainforests, with more than 850 described species distributed worldwide and 124 species in Africa. Fig trees occupy diverse habitats and attain a wide range of growth forms, including large woody climbers, hemiepiphytes, trees, and shrubs. Over 1200 species globally feed on Ficus fruits and over 10% of the world’s birds and 6% of mammals consume figs, making them the most widely consumed plant genus. Fig-fruiting phenology is such that they are generally available during periods of food scarcity and may influence entire faunal communities, particularly as a dry season staple food. Therefore, it is a well-known key fruit resource component in tropical forests and one of the most important genera sustaining numerous frugivores across different landscapes. In a mutually beneficial relationship, the plants also benefit from seed dispersal by frugivores taking seeds away from the parent plants to locations of fewer pathogens, enhancing germination and plant recruitment. This study was concerned with the interactions between fruit-producing plants and fruit-eating animals across an urban mosaic landscape in KwaZulu-Natal, South Africa. Specifically, the study focused on Ficus spp. of conservation importance and keystone species. Despite the critical role that figs play in many frugivores' ecology, there is relatively little information on the distribution and diversity of Ficus species along forest-urban gradients in relation to different land uses and frugivore foraging behaviours in the study area. Details of the relationships between different components of the frugivore-seed disperser and different fig species also remain unclear. Thus, this study enhances the understanding of the role of birds, bats and other mammals in seed dispersal, germination, and the effect of land-use changes on fig-frugivore interactions, which is critical for informing conservation and management strategies.
Effects of landscape and forest structural characteristics on the avian communities in Southern Mistbelt Forests, Midlands of KwaZulu-Natal, South Africa.
(2023) Bitani, Nasiphi.; Downs, Colleen Thelma.; Ehlers Smith, David Alan.; Ehlers Smith, Yvette Cathrine.
Globally forest ecosystems are under threat from land-use changes threatening biodiversity. Biodiversity conservation in forest systems has become a major concern as these impacts affect ecosystem functioning. Habitat destruction results in highly fragmented forest patches with reduced habitat quality. Therefore, it is essential to assess species' responses to these changes for conservation. Like other parts of the world, South African forests are threatened by destruction, mainly habitat conversion to exotic commercial tree plantations. Forest bird species within this system have been reported to be declining. Considering these impacts, it is important to understand the main drivers at different spatial scales. This study aimed to assess local and landscape drivers of avian communities in the Southern Mistbelt Forests in the Midlands of KwaZulu-Natal, South Africa. The objectives were to assess (1) the local scale drivers and influences on bird species richness, use and functional diversity, (2) microhabitat requirements and occupancy of understorey forest specialist bird species using camera traps, and (3) landscape attributes influencing bird species richness, habitat use and functional groups. Firstly, the influence of forest structure and composition on bird species richness, habitat use and functional diversity in 14 selected Southern Mistbelt Forest patches of KwaZulu-Natal were assessed. The bird species were surveyed using point count surveys. Functional diversity for each surveyed patch was quantified using three indices: functional richness, functional evenness and functional divergence. Species-specific responses were assessed by focusing on three forest specialists, orange ground-thrush Geokichla gurneyi, forest canary Crithagra scotops, and Cape parrot Poicephalus robustus. Bird community and forest bird specialists' responses to forest structure and tree species diversity varied. Forest structural complexity, canopy cover, and tree species richness were the main structural characteristics influencing bird functional diversity. Also, forest composition and structure are important for bird species and functional richness. Secondly, the microhabitat requirements of forest specialist bird species using camera surveys in the selected 14 Southern Mistbelt Forests were assessed. The results showed that the microhabitat requirements of the understorey forest specialist species are specific. Occupancy models showed that forest specialist understorey birds are mainly influenced by tree species richness, understorey cover of leaf litter and water. Lastly, the bird species richness, habitat use and functional groups’responses to selective logging history, livestock grazing and adjacent matrix type were assessed. The bird communities were surveyed using point-counts. Functional diversity was quantified using functional richness, functional divergence and functional evenness estimated using bird functional traits. The disturbance did not affect bird species richness. Forest specialists' responses to disturbance were species-specific depending on the type of disturbance and intensity. The orange ground-thrush and forest canary were affected by livestock grazing, while the Cape parrot was influenced by forest logging history. Functional richness for all functional groups was high in disturbed forests, while functional evenness for forest specialists and insectivores was low in disturbed sites. The results of this study provide insight into the local and landscape drivers of avian species richness and diversity. Forest patches with high tree species diversity and structural complexity should be maintained to conserve forest specialists, bird species richness and functional richness. Also, to maintain the persistence of the understorey forest specialists, forest structures within 5 m of the forest floor should be maintained. It is recommended to use functional diversity indices with taxonomic indices to understand bird species responses to disturbance better.
Flexibility in metabolic rate in a small Afrotropical bird Zosterops virens.
(2014) Thompson, Lindy Jane.; Downs, Colleen Thelma.; Brown, Mark.
The scientific literature contains hundreds of studies on avian basal metabolic rate (BMR), many of which assumed that BMR was fixed for each species. Yet those from the last few decades have shown avian BMR to be a flexible trait, changing temporarily and reversibly in response to numerous environmental variables. Given that birds from lower latitudes are relatively understudied compared with temperate and Holarctic species, and that seasonal trends in BMR of southern hemisphere birds are not well understood, we looked at seasonal variation in BMR of a small Afrotropical bird, the Cape white-eye (Zosterops virens), over two years, and found that small birds may reverse the direction and amplitude of seasonal change between years. We also looked at circannual rhythm in avian resting metabolism (RMR), and found that peaks and troughs in resting metabolic rate (RMR) may not necessarily correspond with peaks and troughs in ambient temperature, suggesting that some of the confusion regarding the direction and magnitude of seasonal change in avian BMR may be caused by timing of seasonal measurements. Since we were using captive birds for my work, and since captivity may have an effect on avian BMR, we compared the BMR of freshly wild-caught birds with that of long-term captives housed in outdoor aviaries. The captive birds had higher BMR, giving weight to the argument that some physiological data of captive birds should not be used as representative of wild conspecifics, however the direction of seasonal change was similar in freshly wild-caught and long-term captive birds. Along the same vein, acclimation to laboratory conditions, experimental procedure, and different thermal environments, may also affect avian BMR, and thus before we started the final experiment, Cape white-eyes were acclimated to two different thermal regimes, with no change in RMR over an eight-week period, although there was an increase in body mass over the first three weeks, presumably due to the captive diet being of higher quality than a wild one. These results suggested that in some instances, small birds that are freshly wild-caught may not need to be acclimated in terms of their metabolism, before respirometry trials begin. Finally, given that anthropogenic climate change is anticipated to eclipse all other threats to biodiversity, and since many current predictive models pay no heed to metabolic flexibility of birds, we investigated the effect of a 4°C increase in housing temperature on resting metabolism of the Cape white-eye. This temperature increase is equivalent to that predicted for the range of this species by 2080, and therefore gives an indication of the effect of a sustained increase in mean surface air temperature. The results showed only a marginal difference in various metabolic parameters, suggesting that these birds may cope with the mean temperature increase predicted for their range in the coming decades. Together, these results highlight the importance of considering phenotypic flexibility when studying avian resting or basal metabolic rate. This has special implications for seasonal studies that implicitly assume that summer and winter measurements provide snapshots of the maximum and minimum RMR of which birds are capable, and for comparative studies, which may incorporate metabolic data from both wild and captive populations, or from study birds that were acclimated for different periods.
Forest mammalian community dynamics and human wildlife interactions in the Southern Mistbelt Forests of KwaZulu-Natal and Eastern Cape, South Africa.
(2021) Sosibo, Mbalenhle Thabile.; Downs, Colleen Thelma.; Ehlers Smith, Yvette Cathrine.; Ehlers Smith, David Alan.
African and Asian forests are well known for their high faunal and floral diversity; however, many forests have been left degraded or cleared because of anthropogenic activities from the past and present. In particular, African forests have been heavily exploited for their timber resources and land conversion for anthropogenic activities such as agriculture,. South African forests, specifically the Southern Mistbelt Forests, have been subjected to heavy logging by colonial settlers and subsistence harvesting in recent times because of the logging of trees such as yellowwood species (Podocarpus and Afrocarpus spp.) and hunting of bushmeat species blue duiker (Philantomba monticola). The aim of the study was to assess the anthropogenic impacts on mammals occurring in the Southern Mistbelt forests of KwaZulu-Natal and Eastern Cape provinces, as well as other uses of the forest and human-wildlife interactions. Study areas included the disjunct Southern Mistbelt Forests of the northern Eastern Cape and southern KwaZulu-Natal provinces, South Africa. It was conducted in three different forest cluster areas: uMthatha, Glengarry/Weza [termed iNgeli hereafter] and Creighton with forest patches of varying size. We conducted camera-trap surveys between May 2018 – February 2019 during the wet (summer/spring) and dry (winter/autumn) seasons, resulting in one full 21-day survey for each camera-trap location per season. We used infrared motion detection camera-traps to monitor mammalian forest species at set camera-trap locations determined using a 400 m x 400 m systematic grid system overlaid onto Southern Mistbelt Forest patches in Arc GIS v10.5.1. We also conducted semi-structured interviews in all three areas from October to November 2019. When assessing microhabitat use by mammalian species, we found that mammalian species most often photographed during sampling seasons were bushbuck (Tragelaphus scriptus) and samango monkey (Cercopithecus albogularis labiatus), with the least photographed species being serval (Leptailurus serval) and African wild cat (Felis silvestris cafra). Land-use data around each forest patch were extracted, with settlements, exotic timber plantations and grasslands identified as the dominant adjacent land-uses. The importance of exotic tree plantations surrounding indigenous forest patches to the persistence of mammalian species was highlighted. The maturity and condition of exotic timber plantations surrounding forest patches in our study also varied and may have influenced the area's use and suitability by mammalian species. Creighton was the only study area where human settlements were a dominant land-use around patches. The samango monkey had the second highest mean occupancy across all sampling areas and land-use types. Forest mammals make considerable contributions to the functioning of forest ecosystems. We evaluated the response of forest mammal functional diversity and species richness to factors such as patch size. Species β-diversity was greatly driven by turnover and functional β- diversity was driven by nestedness; therefore, management implications of these forests and associated mammalian communities suggest that all patches should be considered a priority for conservation. Due to different management implications, if nestedness is dominant, forest patches that have a higher diversity of species traits and species richness should be prioritised for conservation. Lastly, we aimed to quantify and assess the dynamics of forest use and hunting of mammalian species in communities close to forest patches and found that ungulates are the preferred choice for consumption in lower-income settlements which is supported by many other studies. Different species were hunted for various reasons such as: consumption, monetary gain (bushmeat trade and selling of hides) as well as retaliatory killing of predators hunting livestock. However, respondents shared that the forests are important to them and to protect them guards would be a good choice as well as education and awareness about sustainable use. There is a paucity of information about the overall mammal community inhabiting these forests and this study has highlighted which species inhabit these forests as well as their forest utilisation and how anthropogenic activities affect species populations. Furthermore, it highlighted that communities close to these forests see these forests as areas of high conservation importance.
Habitat use of Long-crested Eagles in human-modified landscapes of KwaZulu-Natal, South Africa.
(2019) Maphalala, Machawe Innocent.; Downs, Colleen Thelma.; Monadjem, Ara.; Bildstein, Keith L.
Loss of natural habitats due to land use change is threatening biodiversity globally, a cause for concern given the resulting loss of essential ecosystem services. Conservation of biodiversity within human-modified landscapes has become a necessity to halt further loss of biodiversity. The Long-crested Eagle Lophaetus occipitalis is an example of a species that can be managed within human-modified landscapes because it occurs in such landscapes, and the protection of its habitat may benefit other species that use the same habitats. The present study aimed to quantify the habitat use of Long-crested Eagles in human-modified landscapes of KwaZulu-Natal Province, South Africa, at various spatial scales and to make recommendations for the conservation of this species in such environments. Biodiversity in KwaZulu-Natal is threatened by anthropogenic activities that include agriculture, timber plantations and built environment. Between August 2016 and September 2017, twelve Long-crested Eagle adults were tagged with geographic positioning system (GPS) transmitters in the KwaZulu-Natal Province. Telemetry data from the tagged eagles were used to estimate sizes of home ranges and habitat selection within home ranges. Home ranges of males and females were 420 ± 180 ha (n = 5) and 315 ± 161 ha (n = 4), respectively, using the kernel density estimator method (href 95%), and were not significantly different, suggesting similar ranging behaviour between sexes. The home range size of the eagles was relatively smaller than estimates reported from other parts of South Africa which may be an indication of high quality habitats for the species in KwaZulu-Natal Province. Home ranges in rural environments predominantly comprised of cropland (33%) and savanna (22%), whereas in suburban environments they comprised of settlements (34%) and exotic tree plantations (23%). In rural and suburban landscapes, the eagles positively selected for natural patches such as wetlands, natural forest, natural forest edge and savanna but avoided exotic tree plantations. Long-crested Eagles nested and roosted in the natural forests available within their home ranges. Road surveys were used to determine land cover variables associated with Long-crested Eagle site occupancy at the landscape scale. ‘Cropland’ was the only land cover variable associated with occupancy and was positively associated with the area of cropland (β = 4.71 ± 2.28). Such results suggest that the apparent increase in abundance of Long-crested Eagles may be partly attributed to increase in cropland area. Although the influence of natural habitats was not significant at the landscape scale, it is less likely that the eagles selected territories based on the amount of cropland alone because they also needed nesting sites in addition to foraging habitats. Overall, Long-crested Eagles appear to be using edges of cultivated fields that have natural vegetation and hunting perches, and thus gaining improved access to prey. Natural patches of habitat add to the heterogeneity of agricultural landscapes making them more suitable for this species, as supported by the habitat preference observed within home ranges results. Wildlife friendly management of farms whereby natural habitats are retained appears to benefit Long-crested Eagles in agricultural landscapes. Admission records from a specialist raptor rehabilitation centre in Pietermaritzburg were examined to identify common threats facing raptors in KwaZulu-Natal and determine factors that could be used to predict the outcome of rehabilitation. The major causes of admission to the rehabilitation centre were collision related injuries (52.1%), grounded birds (11.6%) and orphaned chicks (9.5%). Only the variable ‘reason for admission’ was a significant predictor of the outcome of rehabilitation. Raptors with no severe injuries such as orphaned chicks and grounded birds were more likely to have successful rehabilitation treatment than raptors suffering from collision injuries. In cases where triage is necessary, rehabilitation centres can make such decisions based on the nature of the injuries as this study has demonstrated that birds suffering from collision injuries were less likely to have successful rehabilitation. In the wake of rapidly changing environments, conservation of biodiversity should not be left to protected areas alone, instead people should work together to make human-modified landscapes more habitable to wildlife. The presence of Long-crested Eagles on private properties should be an inspiration to do more to conserve wildlife.
The habitat, nesting and foraging requirements of southern ground-hornbills in the Kruger National Park.
(2016) Combrink, Leigh.; Downs, Colleen Thelma.
Southern ground-hornbills Bucorvus leadbeateri are large, terrestrial, carnivorous birds that inhabit the savanna and bushveld habitats of much of Africa, south of the equator. They were once prevalent in north-eastern South Africa, but as a result of extensive habitat loss and persecution, their population has suffered a significant decline. They are currently listed nationally as Endangered and globally as Vulnerable. In an effort to curtail this decline in South Africa, a National Species Recovery Plan was developed, with reintroductions of the birds into suitable habitat outside of protected areas listed as a viable conservation intervention for the species. This plan also highlighted a number of knowledge gaps which need to be addressed and which are essential to the long-term conservation of the species. The exact habitat requirements (including specifics of nest cavities) and the foraging ecology of southern ground-hornbills were both listed as areas where data are lacking. Consequently the main aim of this study was to determine the habitat, nesting and foraging requirements of the southern ground-hornbills with the intention of developing management guidelines for areas planned as reintroduction sites for the species. Our study focused on the population of southern ground-hornbills located within the Kruger National Park. We found that the particular characteristics of the southern ground-hornbill nest (cavity dimensions, tree species, height of cavity etc.) did not affect nesting success of the birds. The proximity of roads was important, with more successful nests being situated closer to roads. Habitat structure and diversity of vegetation around the nest also influenced the success of the particular group, with nests with more open habitats and a wider variety of vegetation types being more successful. Nest cavity temperatures were significantly different to ambient for selected nests studied across the 2013-2014 and 2014-2015 breeding seasons. We also found that nest temperature did not affect their nesting success. Interestingly, the artificial nest within our study area showed extremes in temperature (significantly higher and lower than ambient maximum and minimum temperatures, respectively) despite this being one of the most successful nests studied. As southern ground-hornbills are carnivorous, they are known to take a variety of prey items and have been considered generalists. One of the important current questions in foraging ecology is whether generalist populations consist of individuals (or in our case, groups) that are all generalists, or if the generalist population comprises a number of dietary specialists. We tested this theory for southern ground-hornbills using stable isotope analyses of feather and bill samples. Our results show that they are obligate generalists at the group level, suggesting that they access and consume prey species in accordance with their availability in the landscape. At the individual level, based on the two bill samples obtained, there could be some form of specialization occurring. With our relatively small sample size we were unable to determine whether this was in fact specialization or whether these results were reflecting local environmental changes, affecting the isotopic signatures of the vegetation and thereby, prey species of southern ground-hornbills. We used satellite tracking technology to investigate home range sizes and habitat use of southern ground-hornbills within the Kruger National Park and surrounding conservation areas. We then used first-passage time analysis to determine whether certain movement behaviours were influenced by habitat type. We found that there were marked seasonal differences in home range size and that all groups showed a range restriction during the wetter months (coinciding with the breeding season), where activities are concentrated around the nest site. Grassland, open woodland and dense thicket habitats were found to be important habitats for foraging and grassland and open woodland areas were used in accordance with their availability within the groups’ respective territories year-round. The results from this study have been consolidated into recommendations for areas being considered as potential release sites for captive-reared southern ground-hornbills. This research investigated what the habitat, nesting and foraging requirements of southern ground-hornbills are with the aim of adding to the current data on the species as well as addressing these knowledge gaps as highlighted in the National Species Recovery Plan. Each aspect of this PhD study provided results that can be used in current and future conservation interventions, and in particular, reintroductions in areas outside of protected areas. These results are applicable to populations within South Africa, but can also be applied to the species across its range.
The influence of the conservation of forests and public attitudes on the persistence of African crowned eagles in the mosaic of eThekwini Municipality, KwaZulu Natal, South Africa.
(2022) Maseko, Mfundo Sibongakonke Terrance.; Downs, Colleen Thelma.; Zungu, Manqoba Moses.
Abstract available in PDF.

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