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Item Precision of helicopter-based total-area counts of large ungulates in bushveld(AOSIS, 2002-12-14) Reilly, B.K.Precision in helicopter total-area counts in bushveld for a range of common species are evaluated. Counts were conducted on properties ranging in size from 250 ha to 10 000 ha as part of experiments on precision and power. Counts were conducted in three vegetation types: mopane veld, sourish mixed bushveld and arid bushveld. Scant regard is given to precision as a factor in large herbivore monitoring, with more effort often devoted to accuracy. Coefficients of variation varied from 3.2 % to 70.9 %. Median values are generally acceptable for the establishment of trends for long-term monitoring but might be inadequate for annual population size monitoring and evaluation. A regression of all species and vegetation types by the standard error showed a significant correlation. Similar regressions were also developed for impala, kudu, warthog, and zebra. Regressions by vegetation type for mopane veld, sourish mixed bushveld, and northwest arid bushveld were also significant. However, the high correlation for some vegetation types might be an artifact of the small sample sizes.Item The phytosociology of the Villiers - Grootvlei area, South Africa: The plant communities of the Ea land type.(Elsevier, 1992-05-15) Breytenbach, P.J.J.; Myburgh, W.J.; Theron, G.K.; Bredenkamp, G.J.The vegetation of the Ea Land Type in the Villiers - Grootvlei area was classified by means of Braun-Blanquet procedures. A total of 77 releves in the land type were used. On the high-lying areas two major plant communities were encountered, one of which was divided into two sub-communities. On the low-lying areas five major plant communities were recorded, one of which was divided into five sub-communities and another into two sub-communities. A DECORANA ordination confirmed that the communities are related to specific environmental conditions.Item The phytosociology of the Villiers - Grootvlei area, South Africa: The plant communities of the Ba Land Type.(Elsevier, 1992-05-15) Breytenbach, P.J.J.; Myburgh, W.J.; Theron, G.K.; Bredenkamp, G.J.The vegetation of the Ba Land Type is classified by means of TWINSPAN and refined by the Braun-Blanquet method, in nine plant communities. One of the communities is divided into two SUb-communities. The plant communities were related to specific environmental conditions that were confirmed by the ordination (DECORANA) of the data.Item Differences in the dietary habits of verreaux’s eagles aquila verreauxii between peri-urban and rural populations.(Cambridge University Press (CUP), 2020-01-04) Padayachee, Kailen; Malan, Gerard; Lubcker, Nico; Woodborne, Stephan; Hall, GrantDifferences in the diets of urban and rural avian predators could indicate potential niche vulnerability in a particular habitat. This study compares the core-isotopic niche areas and diet disparity of a declining peri-urban Verreaux’s Eagle Aquila verreauxii population with a stable rural population in South Africa. In addition to stable isotope analyses, the diet of the peri-urban Verreaux’s Eagles was investigated using camera trap footage of prey delivered during the nesting season. Dominant prey consisted of species with a mixed diet of plants with a C3 and/or C4 photosynthetic pathway (browsers and grazers). Rock hyrax Procavia capensis contributed 60%of the total diet composition, scrub hare Lepus saxatilis 26% and Helmeted Guineafowl Numida meleagris 22%. The coreisotopic niche area for each population was calculated using bulk carbon (13C) and nitrogen (15N) stable isotope values chronological measured along the length of 18 feathers from 21 nests. The isotopic niche of the rural eagle population revealed that they consume prey from multiple trophic levels with a C3-plant-dominated prey base (browsers), likely including small carnivores. In contrast the isotopic niche of the peri-urban Verreaux’s Eagles correlated with the mixed mammalian and avian food-niche determined from camera trapping, confirming that the peri-urban population mainly hunted three abundant species that are all narrowly associated with modified human habitats. The decline in the Magaliesberg Verreaux’s Eagle population is, therefore, unlikely to be due to constraints in their dietary niche, as raptors benefit from the diversity and abundance of human-commensal prey associated with the peri-urban habitats.Item Fine-scale habitat requirements of the Heidelberg Opal butterfly (Chrysoritis aureus) in Gauteng and Mpumalanga, South Africa.(South African National Biodversity Institute (SANBI), 2017-09-11) Deysel, Rouxdene; Myburgh, Willem J.; Panagos, Mike D.Background: This study quantified the fine-scale habitat requirements of Chrysoritis aureus, at 11 known habitats in Gauteng and Mpumalanga, South Africa, in order to make habitat management recommendations for this endangered species. Objectives: The habitats were quantified in terms of plant species composition and structure with reference to their environmental characteristics. Method: A modified area-based phytosociological approach was used to collect floristic data along with environmental characteristics of habitats occurring on the Witwatersrand and Ventersdorp Geological Systems. Results: Species recorded were predominantly forbs and graminoids with a slightly higher number of plant species in the habitats of the Ventersdorp Geological System. Few dwarf shrubs and shrubs and very few trees were recorded. A higher number of plant species were recorded during the late growing season on both geological systems. The butterfly food plant Clutia pulchella var. pulchella L. (Euphorbiaceae) was recorded in all the habitats and was dominant in habitats in both geological systems. The occurrence of the food plant is essential for the survival of the butterfly at these habitats. Conclusion: Monitoring of the C. aureus butterfly populations and of the vegetation structure, species composition and growth forms to determine trends in the vegetation condition after planned fires; regular burning of the habitats in order to maintain suitable vegetation composition and structure; and the monitoring and eradication of alien invader plants are very important management activities to ensure the conservation of C. aureus.Item The phytosociology of the Villiers - Grootvlei area, South Africa: The plant communities of the Ib land type.(Elsevier, 2017-01-27) Breytenbach, P.J.J.; Myburgh, W.J.; Theron, G.K.; Bredenkamp, G.J.The vegetation of the Ib Land Type in the Villiers - Grootvlei area was classified by means of the Braun Blanquet method. A total of 41 releves in this land type were used. Six main plant communities were identified, with one of the communities divided into two sub-communities. The plant communities were related to specific environmental conditions that were confirmed by the ordination (DECORANA) of the data.Item Identifying potential protected areas in the Grassland Biome of South Africa.(Academy of Science of South Africa (Commercial Publishers), 2020-08-17) Prinsloo, Helen; Reilly, Brain; Myburgh, WillemSouth Africa is considered to be one of the most biologically diverse countries in the world. The conversion, degradation, and fragmentation of natural habitats have caused a loss of biodiversity in many areas. Grasslands have been widely recognised as important for both biodiversity and economic development. Many conservation efforts have in the past been theory driven, without actionable, feasible results. We hypothesised that correct implementation of the available data will indicate where conservation efforts should be focused to move closer to achieving targets for biodiversity conservation in the Grassland Biome in South Africa. We identified an area (near Heilbron and Petrus Steyn in the Free State) that is representative of the biodiversity in the region and is suitable for modern conservation efforts in the ‘real world’. This approach provides a practical look at conservation in the modern era and a feasible result for conservation efforts. Significance: • An area in the Free State Province was identified that has a high level of biodiversity representative of the Grassland Biome in South Africa. A subjective process was implemented to ensure that the area represents the factors that are considered important for conservation, land use and appropriate location in order to make the area a feasible target for conservation. The result therefore represents not only a theoretical finding that is based on data analysis, but also a practical approach to ensure that the findings can be implemented. This study is an effort to provide a baseline for a more modern approach to conservation, in which current land use, economic value and conservation value are all considered to achieve a sustainable result in terms of the conservation of biodiversity.Item Macro channel riparian vegetation of the Olifants River System in the Savanna Biome, Mpumalanga.(Aosis, 2004-12-18) Myburgh, W.J.; Bredenkamp, G.J.The vegetation associated with the macro channel of the Olifants River System was investigated to identify plant communities mappable at a spatial scale of 1:250 000. The results obtained by applying the PHYTOTAB PC classification and mapping program package revealed nine distinct plant communities associated with that section of the river system that flows through the Savanna Biome.Item The distribution and extent of declared weeds and invader plants in the macro channel of the Olifants river system, Mpumalanga.(AOSIS Publishing, 2005-06-30) Myburgh, W.J.; Bredenkamp, G.J.The vegetation associated with the macro channel of the Olifants River System was investigated to distinguish plant communities at a spatial scale of 1:250 000. The floristic data were analysed in terms of the sectional and longitudinal distribution and extent of declared weeds and invaders recorded during the survey. The results gained using the PHYTOTAB PC-classification and mapping program package revealed eight Grassland Biome and nine Savanna Biome plant communities from it's origin near the town of Breyten up to the border of the Kruger National Park. It was found that different invader species/weeds are associated with different biomes and habitats along the river system and that an alarming number of these species occur throughout the system.Item Pleistocene large reptile tracks and probable swim traces on South Africa’s Cape south coast.(Academy of Science of South Africa [Commercial Publisher], 2019-11-08) Helm, Charles W.; Cawthra, Hayley C.; Combrink, Xander; Helm, Carina J.Z.; Rust, Renée; Stear, Willo; Van den Heever, AlexThe Cape south coast of South Africa contains a wealth of Pleistocene vertebrate trace fossil sites in aeolianites and cemented foreshore deposits. Published studies have described mammal and avian tracksites identified along this coastline. We report here on a number of Pleistocene palaeosurfaces within the Garden Route National Park that exhibit tracks of large reptiles, including probable swim traces. The tracks were probably made by more than one species, and may include a crocodylian. There are no extant reptiles in this coastal region capable of making such tracks and traces, which probably represent an indication of a previously more extensive range for the Nile crocodile and a monitor lizard. These findings demonstrate the potential for ichnology to complement the traditional body fossil record. Two Middle Stone Age stone artifacts were found embedded in one palaeosurface containing multiple reptile trackways. These discoveries have implications for the understanding of Pleistocene palaeoenvironment and palaeoclimate - in an area which is important in the study of modern human origins. SIGNIFICANCE: • Large reptile Pleistocene fossil tracksites have recently been discovered on the Cape south coast of South Africa where there are no previous such records, and no reptiles of this size are currently found in the region. • These sites include the first reported probable reptile swim traces in Africa and one tracksite also contained two Middle Stone Age artifacts. • These discoveries have implications for Pleistocene environments and climate on the Cape south coast.Item The population status of the endangered endemic plant Aloe peglerae: Area of occupancy, population structure, and past population trends.(Elsevier, 2014-04-24) Phama, J.O.; Panagos, M.D.; Myburgh, W.J.; Pfab, M.F.Aloe peglerae Schönland is a rare succulent plant species, which is endemic to South Africa. The species is currently listed as Endangered and is threatened mainly by illegal collection. The aim of this study was to determine the population status of Aloe peglerae in the Magaliesberg Mountain Range, that is, whether the population is declining, stable or increasing. Key population parameters assessed for this study included plant density, population structure, area of occupancy, population size, and rate of past population decline. Nine subpopulations were surveyed in 2009 and 2010 using a distance sampling technique. Also, these data were compared to data collected in 1999 by the Gauteng Department of Agriculture, Conservation and Environment, so as to determine possible population trends. The results showed a decline of 43% in mean population density between 1999 and 2010, suggesting that the population of Aloe peglerae in the Magaliesberg is in a state of decline. The application of this technique to plant populations is relatively novel and key recommendations are provided to improve survey design.Item A comparison of three dry matter forage production methods used in South Africa.(Hans Publishers, 2014-04-11) Joubert, A. J.; Myburgh, W. J.A common method for determining forage production of rangelands is by clipping and weighing forage from quadrats with redetermined areas. This technique is however time consuming. Other techniques which require less time and labour include amongst others using the disk pasture meter or phytomass derived from the vegetation classification program PHYTOTAB, in conjunction with the Plant Number Scale, which is used to determine vegetation canopy cover. The phytomass determined using PHYTOTAB/Plant Number Scale and the disk pasture meter was compared to the phytomass obtained from the actual clipping and weighing of forage. Tests showed that there were indeed statistically significant differences between the mean phytomass values of the three techniques. Considerable variation was shown in the results of the disk pasture meter readings compared to the other two techniques. The phytomass values obtained using the disk pasture meter were significantly higher than the phytomass determined using both the PHYTOTAB/Plant Number Scale and the clipping and weighing techniques. Results further indicated a significant similarity in the phytomass determined using the PHYTOTAB/Plant Number Scale and the clipping and weighing technique. The results of this pilot study need further investigation.Item Macro-channel riparian vegetation of the Olifants river system in the Grassland biome, Mpumalanga.(Aosis, 2004-12-18) Myburgh, W.J.; Bredenkamp, G.J.The vegetation associated with the macro-channel of the Olifants River System was investigated to identify plant communities mappable at a spatial scale of 1:250 000. The results obtained by using the PHYTOTAB PC-classification and mapping program package, revealed eight distinct plant communities associated with the macro-channel of this river system that occurs within the Grassland Biome.Item Organochlorine pesticide bioaccumulation in wild Nile crocodile (Crocodylus niloticus) fat tissues: Environmental influences on changing residue levels and contaminant profiles.(Elsevier, 2020-09-27) Humphries, Marc S.; Myburgh, Jan G.; Campbell, Robert; Buah-Kwofie, Archibold; Combrink, XanderBiologically significant concentrations of organochlorine pesticides (OCPs) continue to be reported in wildlife populations and are of particular concern in species that occupy the highest trophic levels. Nile crocodiles (Crocodylus niloticus) are important apex predators occurring throughout much of tropical and subtropical sub-Saharan Africa, where they inhabit estuarine and freshwater habitats often impacted by contamination. In this study we examined pesticide residue accumulation in fat tissue from Nile crocodiles at Lake St Lucia, South Africa, where historically large quantities of OCPs have been used for agriculture and disease control. During 2019, we collected tail fat samples from wild (n = 21) and captive (n = 3) individuals to examine the influence of habitat, body size and sex on variations in bioaccumulation. The principal contaminant found was p,p′-DDE, a major persistent metabolite of DDT, which continues to be used in the region for combating malaria. Tissue p,p′-DDE concentrations in wild crocodiles (95–1200 ng g−1 ww) were significantly (p < 0.05) higher compared to captive individuals (23–68 ng g−1 ww) and strongly correlated (R2 > 0.70) to body length. Male (n = 14) and female (n = 7) wild crocodiles exhibited similar contaminant body burdens, however, total concentrations were substantially lower than those measured in the same population during 2016/2017. Marked differences in residue levels and profiles appear to reflect changes in food availability and dietary exposure associated with a shift in environmental conditions. These findings suggest that periods of environmental stress may be associated with enhanced toxicological risk in crocodiles. Additional work is needed to better understand contaminant accumulation and elimination mechanisms in crocodiles, and their potential effects on reproductive health.Item The impact of Eucalyptus plantations on herpetofaunal diversity, Maputo National Park, Mozambique.(Taylor and Francis Group, 2023-12-08) Jordaan, P.R.; Wilken, A.; Combrink, X.Exotic afforestation has proven detrimental to biodiversity in general, however only a few studies documenting the impact of timber plantations on herpetofaunal diversity have been published within a southern African context. To determine if variations in herpetofaunal species assemblages could be detected between derelict Eucalyptus plantations, cleared plantation woodlots, and untransformed sand thicket vegetation, a pitfall and funnel trap survey was conducted in coastal southern Mozambique. Herpetofaunal species richness for derelict Eucalyptus plantations was 13 ± 2.24 species, untransformed sand thicket vegetation 17 ± 2.34 species and cleared plantation woodlots 18 ± 3.14 species. Both Shannon-Weaver and Simpson Diversity Indices estimated the highest herpetofaunal species diversity in untransformed sand thicket vegetation and the lowest diversity in derelict Eucalyptus plantations. The herpetofaunal species assemblages of derelict Eucalyptus plantations and natural sand thicket vegetation were least similar (0.507 ± 0.041), while cleared plantation woodlots and derelict Eucalyptus plantations were most similar (0.753 ± 0.032) in terms of herpetofaunal community composition. In contrast to our expectations, significantly higher capture rates were reported for a fossorial anuran in derelict Eucalyptus plantations compared to both cleared plantation woodlots and untransformed sand thicket vegetation, which requires further investigation and discussion. As with most other studies investigating the effects of exotic timber plantations on biodiversity, our results indicate that the detectable herpetofaunal diversity decreased in Eucalyptus plantations when compared to natural or cleared plantation woodlots. Subsequently it would seem as though the active clearing of dilapidated timber plantations as part of rehabilitation efforts may positively affect herpetofaunal diversity.Item Estimating total length of partially submerged crocodylians from drone imagery.(MDPI Commercial Publisher, 2024-03-11) Aubert, Clément; Le Moguédec, Gilles; Velasco, Alvaro; Combrink, Xander; Lang, Jeffrey W.; Griffith, Phoebe; Pacheco-Sierra, Gualberto; Pérez, Etiam; Charruau, Pierre; Villamarín, Francisco; Roberto, Igor J.; Marioni, Boris; Colbert, Joseph E.; Mobaraki, Asghar; Woodward, Allan R.; Somaweera, Ruchira; Tellez, Marisa; Brien, Matthew; Shirley, Matthew H.Understanding the demographic structure is vital for wildlife research and conservation. For crocodylians, accurately estimating total length and demographic class usually necessitates close observation or capture, often of partially immersed individuals, leading to potential imprecision and risk. Drone technology offers a bias-free, safer alternative for classification. We evaluated the effectiveness of drone photos combined with head length allometric relationships to estimate total length, and propose a standardized method for drone-based crocodylian demographic classification. We evaluated error sources related to drone flight parameters using standardized targets. An allometric framework correlating head to total length for 17 crocodylian species was developed, incorporating confidence intervals to account for imprecision sources (e.g., allometric accuracy, head inclination, observer bias, terrain variability). This method was applied to wild crocodylians through drone photography. Target measurements from drone imagery, across various resolutions and sizes, were consistent with their actual dimensions. Terrain effects were less impactful than Ground Sample Distance (GSD) errors from photogrammetric software. The allometric framework predicted lengths within ≃11–18% accuracy across species, with natural allometric variation among individuals explaining much of this range. Compared to traditional methods that can be subjective and risky, our drone-based approach is objective, efficient, fast, cheap, non-invasive, and safe. Nonetheless, further refinements are needed to extend survey times and better include smaller size classes.Item Fire-associated reptile mortality in Tembe Elephant Park, South Africa.(SpringerOpen Commercial Publisher, 2020-01-21) Jordaan, Philip R.; Steyl, Johan C. A.; Hanekom, Catharine C.; Combrink, XanderBackground: Even though fire has been used extensively as part of conservation management in South Africa, its impact on the life history and mortality of fossorial reptiles is poorly documented. We conducted post-fire transects after three controlled burns during different seasons in Tembe Elephant Park, recorded 14 reptile species, and found fewer mortalities in winter compared to spring. Results: Histopathological examinations of species were conducted from different microhabitats to elucidate the possible cause of death. The unburned condition of most mortality specimens prompted suspicion of particulate smoke inhalation as a possible cause of death. However, the relative absence of carbon-rich particulate matter and the occasional presence of pulmonary oedema suggested asphyxiation, heat-induced cardiac arrest, or gas intoxication as the most likely cause of death. The association of most specimens with microhabitats rich in leaf litter may indicate higher reptile densities in this habitat or increased mortalities due to smoldering detrital material, or both. Detrital combustion and smoldering may result in advective transportation of heated gasses into underlying soil layers, with subsequent increased mortalities. Conclusion: Even though burrowing could potentially offer protection from fire to fossorial vertebrates through vertical movements into deeper substrate, our results indicated that they are not necessarily protected from fire effects. We speculate that seasonal reproductive behavior may contribute to fire mortality. These observations may contribute to improved understanding and management of fire in areas where fossorial reptiles occur.Item Synthesizing Nile crocodile Crocodylus niloticus attack data and historical context to inform mitigation efforts in South Africa and eSwatini (Swaziland).(Cambridge University Press, 2018-08-08) Pooley, Simon; Botha, Hannes; Combrinx, Xander; Powell, GeorgeConflicts with wildlife are a major challenge for conservation across Africa, and Nile crocodiles Crocodylus niloticus are allegedly responsible for more attacks on people than any other species; however, there is a lack of data regarding such attacks. We analysed reported attacks on people by Nile crocodiles in South Africa and eSwatini (Swaziland) during 1949-2016, identifying spatial and temporal patterns in attack incidence, as well as victim demographics. Through a literature review and archival searches we identified records of 214 attacks. Most attacks occurred in natural water bodies, with attacks in dams increasing since 2000. Most victims were attacked while swimming or bathing, others while fishing, doing domestic chores, and crossing waterways. There was a significant relationship between gender and activity when attacked. Children ( <16 years old) accounted for 51% of all attacks, with a higher fatality rate compared to adults. Most victims were male (65%), with teenage boys being the largest individual category. We make recommendations for conservation policy and management to mitigate attacks by Nile crocodiles.Item Use of an area-based survey technique to detect vegetation changes in Sour Bushveld.(AOSIS Publishing, 2006-12-01) Panagos, M.D.; Reilly, B.K.Most strategies for monitoring vegetation change on reserves and game ranches are based on point methods. Area-based methods form the basis of initial floristic classifications from which vegetation maps are constructed. The question arises whether or not these area-based methods can be used for monitoring or not. This paper compares two area-based data sets from the same sites with an intervening period of five years. Data were collected on a Sour Bushveld game farm, in the Limpopo Province of South Africa. The structure of the woody vegetation, particularly in two communities reflected a plant successional progression over time. All six re-surveyed sites reflected an increase in plant species richness and this increase was most substantial in one community where the total number of plant species increased from 17 in 1996 to 34 in 2001 at one sampling site and from 26 in 1996 to 45 in 2001 at the other. This study has shown that change in species composition can be detected using area-based sampling techniques but that absolute measures, such as density, should be employed rather than estimates, especially with regard to plant cover.Item Management of hybridization in an endemic species: decision making in the face of imperfect information in the case of the black wildebeest—Connochaetes gnou.(Springer, 2011-08-05) Grobler, J. Paul; Rushworth, Ian; Brink, James S.; Bloomer, Paulette; Kotze, Antoinette; Reilly, Brian; Vrahimis, SavvasHybridization between introduced and endemic ungulates, resulting from anthropogenic actions, has been reported for several species. Several studies of such events contain the common themes of extralimital movements, problematic phenotypic and genetic detection, and imperfect management. In southern Africa, the endemic black wildebeest (Connochaetes gnou) currently faces a serious threat of hybridization and introgression. This species survived near extinction and consequent genetic bottlenecks in the late 1800s and in the 1930s. Initiatives by private farmers followed by conservation authorities led to a dramatic recovery in numbers of this species. However, in an ironic twist, the very same advances in conservation and commercial utilisation which led to the recovery of numbers are now detecting hybrid animals or herds, the lack of consensus on the fate of hybrid herds is discussed. Finally, in an environment of imperfect information, we caution against implementation of management responses that will potentially induce a new genetic bottleneck in C. gnou.