The Knysna seahorse Hippocampus capensis is South Africa’s only endemic seahorse species, and is found in only three adjacent estuaries along the southern coast. The conservation of this endangered species is important on a national and international level. This study presents the first research on this species within the Knysna estuary since 2001 and specifically focuses on aspects of its ecology within a residential marina estate (Thesen Islands Marina). The physico-chemical and habitat features of the marina were described and the population ecology, habitat use, and behaviour of the Knysna seahorse were investigated. Physico-chemical conditions within the western section of the marina, characterised by high water current velocities, were similar to that of the adjacent estuary. The eastern section of the marina was characterised by lower water current velocities and higher turbidity. Four major habitat types were identified within the marina canals: (I) artificial Reno mattress (wire baskets filled with rocks); (II) Codium tenue beds; (III) mixed vegetation on sediment; and (IV) barren canal floor. Seahorse densities within the marina were significantly higher compared to densities found historically within the estuary. Highest seahorse densities were specifically found within the artificial Reno mattress structures and within the western section of the marina. Seahorse density varied spatially and temporally and the type of habitat was an important predictor for seahorse occurrence. An experimental investigation found that H. capensis chooses artificial Reno mattress habitat over Zostera capensis when given a choice. GoPro cameras were used successfully to investigate daytime seahorse behaviour within the Reno mattress habitat. Seahorses were more active during the morning, spent most of their time (> 80 %) feeding, and morning courting behaviour for this species were confirmed. However, during the summer holiday period (mid-December to mid-January) few seahorses were observed on camera, which suggests that the increase in motor boat activity and the related increase in noise had a negative effect on H. capensis feeding and courting behaviour. The marina development, and in particular the Reno mattresses, created a new habitat for this endangered species within the Knysna estuary. In addition to the protection and restoration of natural habitats in which H. capensis is found, the conservation potential of artificial structures such as Reno mattresses should be realised.

In response to a growing concern over the rising rates of extinction of the world's plants and of habitat destruction, studies of Southern African threatened plants were initiated in the 1970's. These studies, which have largely concentrated on Western Cape flora, led to the publication of "Threatened Plants of Southern Africa" by Hall et al., 1980, which attempted to list as many threatened or possibly threatened species as possible. It was however marred by a lack of recent herbarium records and detailed studies from many parts of the region, the Eastern Cape being one of these. In order to extend these detailed studies to gain a clearer picture of the numbers of threatened species in the Eastern Cape and evaluate the conservation status of Eastern Cape vegetation this project was initiated. Initially lists of possibly threatened and endemic taxa of the Eastern Cape were compiled from various sources. These listed taxa were then checked against herbarium records, all available information being filled onto index cards for filing purposes. This paper-based filing system was then transferred into a computer-based data bank to facilitate the efficient storage and retrieval of information. Results from this data bank show that there are 662 variously threatened plant taxa in the Eastern Cape, many of which fall into temporary categories which need to be clarified by investigation in the field. Primarily based on the above results, a table ranking the various vegetation types into an order of priority for investigations about conservation requirement was developed.Subtropical Thicket was found to be the vegetation type in most need of investigation and so an extensive phytosociological survey was carried out in the Valley Bushveld which forms the major portion of Subtropical Thicket in the Eastern Cape. Twelve sites were sampled for floristic and environmental variables along a rainfall gradient of between 300 mm yr⁻¹ and 1 000 mm yr⁻¹ and along a longitudinal gradient from the Buffalo River in the east to the Gamtoos-Kromme complex in the west. Floristic data W(re analysed using multivariate techniques of classification and ordination. A classification by two-way species indicator analysis revealed the Valley Bushveld to consist of two orders of thicket, the Kaffrarian Succulent Thicket containing the two suborders, Inland Succulent Thicket and the Coastal Succulent Thicket and the Kaffrarian Thicket containing Coastal Kaffrarian Thicket and Inland Kaffrarian Thicket. Ordina tion by detrended correspondence analysis also grouped sites according to these vegetation categories in a sequence along one axis, to which the rainfall gradient could be related. Variables such as diversity indices, numbers of endemics, numbers of threatened taxa and structural features were also extracted from the data and these were correlated with environmental variables by multiple regression analysis. Species richness and the percent woody component w\!re positively correlated with rainfall while endemism and percent succulent component were strongly negatively correlated with rainfall. Most of the other relationships were explained by interrelationships with rainfall. Finally the sites were evaluated according to floristic criteria indicative of conservation value. The Coastal Succulent Thicket appeared to have the highest conservation value mainly owing to high endemism, while Inland Kaffrarian Thicket was also important as it supports a high number of species. The thickets with high conservation value are therefore the thickets of coastal areas in the western parts of the Eastern Cape which receive a low rainfall and the thickets which receive a rainfall in excess of 800 mm. / KMBT_363 / Adobe Acrobat 9.54 Paper Capture Plug-in

The study involved the predator-prey interaction of three species namely the predator (Cheetah Acinonyx jubatus), the super-predator (Lion Panthera leo), and their common prey (Impala Aepyceros melampus). The study area is the Kruger National Park. The predator being an endangered species, faces a survival problem. It is frequently killed by the super-predator to reduce competition for prey. The super-predator also scares away the predator o_ its kills. The prey forms the main diet of the predator. The plight of the predator motivated the author to formulate disease and reaction-diffusion models for the species interactions. The purpose of the models were to predict and explain the effect of large competition from the super-predator on the predator population. Important parameters related to additional predator mortality due to presence of super-predator, the disease incidence rate and induced death rate formed the focal points of the analysis. The dynamics of a predator-prey model with disease in super-predator were investigated. The super-predator species is infected with bovine Tuberculosis. In the study, the disease is considered as biological control to allow the predator population to regain from low numbers. The results highlight that in the absence of additional mortality on the predator by the super-predator, the predator population survives extinction. Furthermore, at current levels of disease incidence, the super-predator population is wiped out by the disease. However, the super-predator population survives extinction if the disease incidence rate is low. Persistence of all populations is possible in the case of low disease incidence rate and no additional mortality imparted on the predator. Furthermore, a two-species subsystem, prey and predator, is considered as a special case to determine the effect of super-predator removal from the system, on the survival of the predator. This is treated as a contrasting case from the smaller parks. The results show that the predator population thrives well in the total absence of its main competitor, with its population rising to at least twice the initial value. A reaction-diffusion three-species predator-prey model was formulated and analysed. Stability of the temporal and the spatio-temporal systems, existence and non-existence of stationary steady state solutions were studied. Conditions for the emergence of stationary patterns were deduced. The results show that by choosing the diffusion coeffcient d2 > _D 2 suffciently large, a non-constant positive solution is generated, that is, stationary patterns emerge, depicting dispersal of species. Predators were observed to occupy habitats surrounding prey. However, super-predators were observed to alternate their habitats, from staying away from prey to invading prey habitat. In the investigation, strategies to determine ways in which the predator species could be saved from extinction and its population improved were devised, and these included isolation of the predator from the super-predator.

Eland Tragelaphus oryx are the largest and slowest African antelope, falling within the preferred weight range of the prey of lions Panthera leo. Little is known, however, about the antipredatory strategies employed by eland. Rapid population declines in several small reserves following the reintroduction of lions suggest that the antipredatory strategies of eland may be compromised in spatially limited areas. This emphasises the need for research aimed at investigating how eland respond to lions, particularly in the spatial context, given that lions are increasingly being reintroduced into small reserves in South Africa. This study aimed to investigate lion-eland interactions at multiple scales and determine where on the landscape eland were vulnerable to predation. Adult female eland (n = 3 per site) in breeding herds were collared with GPS satellite collars in two study sites; the Nyathi section of Addo Elephant National Park (Nyathi) and Mountain Zebra National Park (MZNP) in the Eastern Cape, South Africa. A reintroduced population of lions, comprising two males and one female, was present in each study site, with individuals fitted with GPS satellite collars. At a broad spatiotemporal scale, eland did not avoid lions and there was considerable overlap between eland and lion home ranges in both study sites. At a finer spatiotemporal scale however, eland and lion space use was asynchronous in time, except in the case of the female lion in Nyathi where there was considerable overlap at the finest temporal scale investigated (i.e. monthly). Herd-associated eland in Nyathi were killed most frequently in areas associated with high long-term use by the female lion, showing that failure to avoid the female lion at a fine scale increased predation risk for eland. Secondly, eland in Nyathi were killed most frequently in habitat types of intermediate structural density (i.e. mixed habitats), which limited the viewshed of eland but presumably offered increased forage. This habitat type was selected for by eland, despite it being associated with a higher level of predation risk. This suggested that eland in Nyathi traded off safety for forage. In MZNP, predation of herd-associated eland was low which reflected the limited spatial overlap between eland and lion at a fine scale in this reserve. In Nyathi, but not in MZNP, eland responded to lions within 1.5 km by increasing their movement rate, with this response particularly strong at night. The findings of this study show that eland responses to lions are scale-dependent and site-specific. Furthermore, eland responses to lions were shown to be lion gender-specific. This study has increased our understanding of the antipredatory behaviours of eland and demonstrated the importance of investigating prey responses to predation risk at multiple scales.

Thesis (MScConsEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2006. / Using the World Conservation Union’s (formerly the International Union for the Conservation of Nature) IUCN 2001 categories and criteria, the conservation status of the South African butterfly fauna has been reassessed. This study includes an assessment of the 62 globally threatened South African taxa and 1 that has a marginal distribution in this region.

The Karkloof blue butt erfly, Orachrysops ariadne (Butler), is endemic to the Mistbelt grassland of KwaZulu-Natal province, South Africa, and is currently Red-listed as 'Vulnerable' . O. ariadne is univoltine and on the wing in March and April, when it utilizes eight species of nectar plants. This study confirmed that the larval hostplant is Indigofera woodii H. Bol. var. laxa H. Bol., an erect variety. It was also confirmed that this butterfly is ant-dependent, with the young larva being taken into the nest of Camponotus natalensis (F. Smith) where development continues, including pupation. This study compares the ecological conditions at the four known locations so as to make informed decision s regarding its conservation. A large proportion of the grassland in KwaZulu-Natal has been aforested and cultivated, and at least 92% of the Mistbelt has been transformed, with only about 1% in good condition remaining. Predictions on the habitat and habit at requirements of this species are necessary for developing a conservation strategy and action plan. Here , we propose O. ariadne as an indicator species for Mistbelt grass land. Saving enough of the remaining Mistbelt grassland is crucial, not just for the survival of the Karkloof blue, O. ariadne, but also for the Mistbelt grassland community as a whole. The population structure and movement of Orachrysops ariadne and O. subravus were studied by mark-release-recapture methods in 1999. There were 290 O. ariadne marked over 48 days between March and April, 124 (42 .8%) were recaptured at least once. Of 631 O. subravus marked over two months between September and November, 311 (49 .3%) were recaptured at least once. Both species exhibited protandry, male appearance about one to two weeks earlier. The sex ratio of O. ariadne is heavily male biased 5.6 :1 (246 males and 44 females), and the sex ratio of O. subravus is 1.6:1 (387 males and 244 females). The Jolly-Seber model was used to estimate daily population numbers (N ᵢ), survival rates (Ø ᵢ), recruitment rates (B ᵢ), proportion of marked animals in the total population (α ᵢ ), and the number of marked animals at risk (M ᵢ) . Average residence times of male adults were generally similar in both species in the range of 5.36-5.44 days, and were slightly longer for male than for female O. subravus (by 4.09 days). 0. ariadne is a strong and rapid back and forth flier, covering mean recapture distances of 157 m, almost twice that of 0. subravus, principally in search of scarce nectar sources. The extreme rarity of 0. ariadne is not so much to do with behaviour, survivorship or longevity, but rather the butterfly is limited in distribution by suitable habitat for both larva and adult. The aim of management is to optimize the habitat so that it best meets the present and future needs of the butterfly. The effects of the current fire regime on the butterfly, host plant and ant host were evaluated here. It is recommended that burning only take place after the larvae have hatch ed and gone underground with the ant host. Using GPS and GIS, core, quality habitat characteristics were defined. In cooperation with the landowner at one site, alien invasive plants are being removed to increase the area of quality habitat. Availability of host plants is limiting for success of the butterfly in the field. Guidelines are provided for propagation and introduction of the host plant, so as to provide the butterfly with more oviposition sites. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2002.

Thesis (LLM.) -- University of Limpopo, 2016 / Rhinoceros (Rhinos) are poached at an alarming high rate in South Africa. The 1973 Convention on International Trade in Endangered Species of wild Fauna and Flora (CITES), prohibited the trade of rhino horns amongst its member states. Even though there are existing pieces of legislation in South Africa to curb the killing and illegal trade of rhino horns, compliance authorities rarely impose stringent sentences on culprits caught poaching rhinos. There should be stringent enforcement of laws on poachers and if caught, perpetrators should be brought to justice in order to deter aspiring or ambitious would-be perpetrators. Amendment of legislation currently used in South Africa on rhino poaching cases, if applied vigorously, would be more developmental in curbing the scourge. The syndicate are highly skilled and well equipped for the execution of illicit poaching. It is in few instances that perpetrators are arrested and prosecuted. Even if arrested and prosecuted, lenient sentences are imposed upon conviction. The most noticeable lacuna in South African Criminal Justice System, is the lack of capacity and skills in investigations and successful prosecutions of rhino poachers. Worst still, despite frequent media reports on the alarming rate of rhino poaching cases, few arrests and convictions are reported. This mini dissertation looks at rhino poaching as an organised crime, and focuses on literature review, legal framework and regulations, as well as comparative study on legislation which can be used to prosecute the perpetrators of this organised crime. The discourse recommends amendment of legislation presently used to prosecute rhino poaching offenders, and advocates that they should be stringently applied in order to curb the scourge.

Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: The geometric tortoise, Psammobates geometricus, found in the Western Cape, South Africa, is one of the world's rarest tortoises. At present, it is only known from five isolated geographical areas, one being the Worcester-Tulbagh Valley. The primary aims of my study were to determine the status of geometric tortoise subpopulations along the Nl highway in the Worcester Valley, to determine the population structure of these subpopulations and, if necessary, to provide recommendations for the mitigation ofNI highway-induced impacts on geometric tortoise subpopulations along the road. All Renosterveld remnants along the Nl between Du Toitskloof and Worcester were surveyed for the presence of geometric tortoises, and tortoise density and population structure were determined for each remnant that supports tortoises. Two geometric tortoise subpopulations on opposite sides of the Nl were identified. In the larger remnant of the two, females dominated both the subadult and adult classes, whereas in the other remnant male frequency was slightly higher than female frequency for the adult class only. In both remnants, adult females were significantly larger than adult males in mean carapace length. Mean body mass for adult females and males also differed significantly in both remnants. Analysis of habitat quality showed that both remnants supporting the geometric tortoise are seriously infested by encroaching indigenous and alien plants. The barrier effect of the Nl highway can be mitigated by constructing underpasses, linking the two remnants on opposite sides of the road. Furthermore, road mortality of tortoises can be avoided by erecting tortoise proof fencing along appropriate sections of the highway in the Worcester Valley. By linking the remnants, the largest single area available to the geometric tortoise in the Worcester Valley will also be formed. An additional aim of my study was to investigate the correspondence of geometric tortoise density in individual habitat remnants to the West-to-East change in vegetation composition/characteristics occurring along the Nl in the Worcester Valley. Vegetation composition/characteristics were thus determined in all remnants also surveyed for tortoises. The West-to-East change in vegetation composition/characteristics of the study area indicates that there is a transition from Renosterveld in the West to karroid veld in the East. / AFRIKAANSE OPSOMMING: Die geometriese skilpad, Psammobates geometrieus, wat in die Wes-Kaap, Suid- Afrika, voorkom, is een van die wêreld se skaarste skilpaaie. Vandag word hierdie skilpad net nog in vyf geïsoleerde geografiese streke gekry, een van hulle die Worcester-Tulbagh Vallei. Die primêre doel van my studie was om die status van geometriese skilpad subpopulasies langs die Nl snelweg in die Worcester Vallei te ondersoek en om die populasiestruktuur van hierdie subpopulasies te bepaal. Verder was die doelook, om aanbevelings te maak oor hoe die impakte van die pad op die geometriese skilpad subpopulasies langs die Nl verminder kan word. Al die Renosterveld oorblyfsels langs die Nl tussen Du Toitskloof en Worcester, en binne die bekende gebied van die geometriese skilpad, is deursoek vir geometriese skilpaaie. Populasiedigtheid en populasiestruktuur van die skilpaaie is bepaal vir elke oorblyfsel wat skilpaaie bevat. Twee geometriese skilpad subpopulasies is gekryaan teenoorgestelde kante van die Nl. In die groter oorblyfsel, het wyfies albei die onvolwasse en volwasse klasse gedomineer. In die ander oorblyfsel is gevind dat die frekwensie van mannetjies ietwat hoër was as die frekwensie van wyfies, maar vir slegs die volwasse kategorie. Binne albei oorblyfsels is gevind dat volwassse wyfies betekenisvol groter in gemiddelde doplengte is as volwasse mannetjies. Gemiddelde liggaamsgewig het ook betekenisvol verskil tussen volwasse wyfies en mannetjies in albei oorblyfsels. 'n Analise van habitatkwaliteit het gewys dat beide oorblyfsels wat die geometriese skilpad ondersteun grootliks ingeneem is deur inheemse indringers, sowel as uitheemse plante. Die versperrings effek van die Nl snelweg kan verminder word deur duikwege te skep wat die twee ooblyfsels, op teenoorgestelde kante van die pad, verbind. Bowendien, deur 'n ondeurdringbare heining langs passende dele van die snelweg in die Worcester Vallei op te rig, sal skilpadmortaliteit vermy word. Deur oorblyfsels te verbind, salook die grootste enkele area, beskibaar aan die geometriese skilpad in die Worcester Vallei, gevorm word. 'n Addisionele doel van hierdie studie was om veranderinge in vegetasie langs 'n wes-na-oos gradient binne die studie area te korreleer met die teenwoordigheid van skilpaaie langs hierdie gradient. Vegetasie samestelling/eienskappe is dus bepaal vir elke oorblyfsel wat deursoek is vir skilpaaie. Die wes-na-oos verandering in vegetasie samestelling/eienskappe binne die studie area wys dat daar 'n oorgang van Renosterveld in die weste na 'n karooagtige veld in die ooste is.

White steenbras Lithognathus lithognathus (Pisces: Sparidae) has been a major target species of numerous fisheries in South Africa, since the late 19th century. Historically, it contributed substantially to annual catches in commercial net fisheries, and became dominant in recreational shore catches in the latter half of the 20th century. However, overexploitation in both sectors resulted in severe declines in abundance. The ultimate collapse of the stock by the end of the last century, and the failure of traditional management measures to protect the species indicate that a new management approach for this species is necessary. The species was identified as a priority for research, management and conservation in a National Linefish Status Report. Despite knowledge on aspects of its biology and life history, little is known about juvenile habitat use patterns, home range dynamics and movement behaviour in estuaries. Similarly, the movement and migration of larger juveniles and adults in the marine environment are poorly understood. Furthermore, there is a complete lack of information on its genetic stock structure. Such information is essential for effective management of a fishery species. This thesis aimed to address the gaps in the understanding of white steenbras movement patterns and genetic stock structure, and provide an assessment of its current conservation status. The study adopted a multidisciplinary approach, incorporating a range of methods and drawing on available information, including published literature, unpublished reports and data from long-term monitoring programmes. Acoustic telemetry, conducted in a range of estuaries, showed high site fidelity, restricted area use, small home ranges relative to the size of the estuary, and a high level of residency within estuaries at the early juvenile life stage. Behaviour within estuaries was dominated by station-keeping, superimposed by a strong diel behaviour, presumably based on feeding and/or predator avoidance, with individuals entering the shallow littoral zone at night to feed, and seeking refuge in the deeper channel areas during the daytime. Conventional dart tagging and recapture data from four ongoing, long-term coastal fish tagging projects, spread throughout the distribution of this species, indicated high levels of residency in the surf zone at the late juvenile and sub-adult life stages. Consequently, juvenile and sub-adult white steenbras are vulnerable to localised depletion, although they can be effectively protected by suitably positioned estuarine protected areas (EPAs) and marine protected areas (MPAs), respectively. It has been hypothesized that adult white steenbras undertake large-scale coastal migrations between summer aggregation areas and winter spawning grounds. The scale of observed coastal movements was correlated with fish size (and age), with larger fish undertaking considerably longer-distance coastal movements than smaller individuals, supporting this hypothesis. Given the migratory behaviour of adults, and indications that limited spawning habitat exists, MPAs designed to protect white steenbras during the adult life stage should encompass all known spawning aggregation sites. The fishery is plagued by problems such as low compliance and low enforcement capacity, and alternative management measures, such as seasonal closure, need to be evaluated. Despite considerable conventional dart tagging effort around the coastline (5 782 fish tagged) with 292 recaptures there remains a lack of empirical evidence of fish migrating long distances (> 600 km) between aggregation and spawning areas. This uncertainty in the level of connectivity among coastal regions was addressed using mitochondrial DNA sequencing and genotyping of microsatellite repeat loci in the nuclear genome, which showed no evidence of major geographic barriers to gene flow in this species. Samples collected throughout the white steenbras core distribution showed high genetic diversity, low genetic differentiation and no evidence of isolation by distance or localised spawning. Although historically dominant in several fisheries, analysis of long-term commercial and recreational catch data for white steenbras indicated considerable declines and ultimately stock collapse. Improved catch-per-unit-effort in two large MPAs subsequent to closure confirmed that MPAs can be effective for the protection of white steenbras. However, the current MPA network encompasses a low proportion of sandy shoreline, for which white steenbras exhibits an affinity. Many MPAs do not prohibit recreational shore angling, which currently accounts for the greatest proportion of the total annual catch. Furthermore, EPAs within the juvenile distribution protect a negligible proportion of the total available surface area of estuaries – habitat on which white steenbras is wholly dependent. Despite some evidence of recent increases in abundance in estuaries and the surf zone in certain areas, white steenbras meets the criteria for “Endangered” on the IUCN Red List of Threatened Species, and for “Protected species” status on the National Environmental Management: Biodiversity Act of South Africa. The species requires improved management, with consideration for its life-history style, estuarine dependency, surf zone residency, predictable spawning migrations and its poor conservation status. The multidisciplinary approach provides valuable information towards an improved scientific basis for the management of white steenbras and a framework for research that can be adopted for other overexploited, estuarine-associated coastal fishery species.

The existence of the rhino is under serious threat. South Africa has experienced a dramatic increase in rhino poaching since 2008. With the current trend of poaching, rhino in South Africa will soon become extinct. The current strategies to protect rhino have proved to be ineffective. The common view is that rhino poaching is morally wrong, and associated with greed and evil intentions and that rhino poaching must be stopped; however, there are two schools of thought regarding two main approaches (in association with current strategies) to be used in order to stop or limit poaching. The first school of thought supports the CITES ban on international trade in rhino horn, and believes that rhino poaching can only be stopped by eliminating demand (the “conventional approach”). The second school of thought is in favour of the legalisation of international trade, and argues that any solutions to the rhino poaching problem must address the underlying economic forces. This is called the sustainable approach. The research aimed to investigate the effectiveness of the ban on international trade in rhino horn, as well as the viability of legalising international trade. The effectiveness of the current strategies was also investigated. A qualitative research design was used, and eighteen participants were selected in order to obtain information by means of semi-structured interviews and questionnaires.The first school of thought supports the CITES ban on international trade in rhino horn, and believes that rhino poaching can only be stopped by eliminating demand (the “conventional approach”). The second school of thought is in favour of the legalisation of international trade, and argues that any solutions to the rhino poaching problem must address the underlying economic forces. This is called the sustainable approach. The research aimed to investigate the effectiveness of the ban on international trade in rhino horn, as well as the viability of legalising international trade. The effectiveness of the current strategies was also investigated. A qualitative research design was used, and eighteen participants were selected in order to obtain information by means of semi-structured interviews and questionnaires. A literature review was also conducted, for the purpose of evaluating the responses of participants, and also for the purpose of validity and reliability. The findings indicated that the scales tip in favor of a well-managed, legalized trade, inter alia, to make funds available to rhino owners, rhino custodians and the government, on the one hand, and, on the other hand, to reduce the reward and increase the risk to the poacher. Findings also indicated that a legalized trade cannot be implemented in isolation; it goes hand in hand with increased security and improved law enforcement, while strategies such as dehorning and translocation still have a role to play. Finally, findings also indicated that communities need to be involved in the sustainable use approach. These communities are currently excluded from the benefits derived from the neighboring protected areas, thereby making them susceptible to being recruited as poachers. / Environmental Sciences / Ph. D. (Environmental Management)