Academic literature on the topic 'Mopane tree'

The southern African Miombo and Mopane ecoregions constitute a unique repository of plant diversity whose diversification and evolutionary history is still understudied. In this work, we assessed the diversity, distribution, and conservation status of Miombo and Mopane tree legumes within the Zambezian phytoregion. Data were retrieved from several plant and gene databases and phylogenetic analyses were performed based on genetic barcodes. Seventy-eight species (74 from Miombo and 23 from Mopane, 19 common to both ecoregions) have been scored. Species diversity was high within both ecoregions, but information about the actual conservation status is scarce and available only for ca. 15% of the species. Results of phylogenetic analyses were consistent with current legume classification but did not allow us to draw any conclusion regarding the evolutionary history of Miombo and Mopane tree legumes. Future studies are proposed to dissect the diversity and structure of key species in order to consolidate the network of conservation areas.

Ascorbic acid contents of stems, leaves and fruits from four selected exotic tree species like Colophospermum mopane, Holoptelea integrifolia, Kigelia pinnata and Putranjiva roxburghii have been analysed. Maximum ascorbic acid contents were found in the fruits of Colophospermum mopane (42.10mg/100g.d.w.) while, minimum in the stems of Kigelia plnnata (22.15mg/100g.d.w).

Abstract:Responses of plants to herbivory are dependent on the type of damage and the ontogenetic stage of the plant. We compared the effects of stem pruning and defoliation on seedlings of Colophospermum mopane, an ecologically important tree species widely distributed in southern Africa. The growth of 160 greenhouse-grown juveniles were measured for 6-mo after germination and then 6-mo after treatments including 50% defoliation, 100% defoliation, 50% stem pruning and controls. Pruning resulted in 30% reductions in total leaf area, height and biomass. Partial defoliation resulted in 30% reductions in total leaf area and plant biomass. However, complete defoliation resulted in a 30% increase in biomass production, a doubling in leaf and lateral branch number, a 45% reduction in leaf size, and no change in total leaf area. Thus, completely defoliated seedlings showed greater performance than those that were only partially defoliated, indicating that C. mopane has become adapted to the chronic and severe defoliation inflicted by Imbrasia belina caterpillars. Comparison of our results with other studies indicates that C. mopane seedlings are less herbivory-tolerant than adults and that pruning has more negative effects than defoliation. Thus, seedling browsers may constrain recruitment in C. mopane, influencing its population dynamics and abundance.

Evaluation of flavonoid contents from four selected exotic tree species like Colophospermum mopane, Holoptelea integrifolia, Kigelia pinnata and Putranjiva roxburghii growing in Rajasthan Desert was carried out. The leaves of selected trees were analysed for flavonoid contents i.e. Quercetin and Kaempferol. Flavonoid contents like Quercetin and Kaempferol were isolated and identified. The maximum total flavonoid contents (17.10mg./gdw) was found in leaves of Putranjiva roxburghii while minimum (9.20mg./gdw) in leaves of Holoptelea integrifolia.

Abstract:Plant responses to herbivory vary depending on herbivory type, yet the comparative effects of defoliation (e.g. by insects) and pruning (e.g. by large mammals) on a single tree species are poorly documented. We investigated this in the Northern Province of South Africa by comparing the regrowth of Colophospermum mopane trees previously defoliated by caterpillars or pruned by elephants, the two main browsers of C. mopane foliage. Shoots were up to 160% and 125% longer after natural (elephant) and simulated pruning and leaves ~25% longer in regrowth after natural pruning (n = 13–15 trees per treatment). Shoot density and chemical defences in leaves (tannin:protein ratio and total polyphenolic concentration) were, however, no different from control trees. Simulated defoliation resulted in statistically insignificant changes to regrowth in terms of leaf and shoot size (both slightly decreased) and shoot density (slightly increased). Natural (caterpillar) defoliation, however, resulted in regrowth with significantly decreased shoot and leaf size (about 50% and 20% of control lengths, respectively), as well as decreased leaf chemical defence. Shoot and leaf length were longer on trees flushing for the first time after pruning and late-season defoliation had a greater negative impact than mid-season defoliation. Despite the differences in regrowth characteristics after pruning and defoliation, mopane plants showed no apparent trade-off in investment between tolerance and resistance after either herbivory type, as neither regrowth nor chemical defence occurred at the expense of the other.

Antimicrobial screening of ethyl ether and alcoholic extracts of leaves of four selected exotic tree species growing in Rajasthan Desert was carried out. Colophospermum mopane, Holoptelea integrifolia, Kigelia pinnata and Putranjiva roxburghii showed positive reactions against bacterial pathogens i.e. Staphylococcus aureus, Escherichia coli and a fungal pathogen Candida albicans.

The global loss of biodiversity has led to relentless calls from conservationists to protect the environment and natural habitats. The objective of this study was to determine the effectiveness of crown diameter for prediction of canopy cover under national park conditions. The study was conducted in Etosha National Park, Namibia in 2015. Three tree species, namely Combretum imberbe, Colophospermum mopane and Terminalia prunioides were considered as representative members of the park species based on their relative population density. The study employed regression analysis to examine the nature of relationships between tree crown diameter (the dependent variable) and tree height, diameter at breast height (DBH) and distance from watering holes as independent variables. The regression coefficients for Combretum imberbe were not significant (P = 0.116; P = 0.431; P = 0.884, respectively), suggesting that crown diameter was not well estimated by these explanatory variables. On the other hand, there were significant relationships between DBH and crown diameter, as well as between crown diameter and tree height. Tree height emerged as the stronger predictor of crown diameter for both Terminalia prunioides and Colophospermum mopane. Therefore, the relationship between tree height and crown diameter as explained by cubic function can further be used to evaluate and estimate canopy cover under national park conditions.

Thesis (M.Sc. (Molecular and Life Sciences)) --University of Limpopo, 2007
Colophospermum mopane (sensu lato) is currently recognised on morphological and physiological characteristics. To add to the suite of taxonomic characters, the genetic variability of C. mopane (sensu lato) was investigated using the RAPD technique. DNA was extracted from young seedlings and mature leaves using the CTAB method. Initially, the DNA extraction was problematic due to the presence of polysaccharides, making PCR nearly impossible. An additional phenol precipitation step was introduced to purify the DNA used to perform RAPD analyses. Twenty random primers were tested for their suitability and reproducibility to reveal polymorphism in C. mopane (sensu lato). Nine of the primers tested amplified the genomic DNA. Subsequently, three primers (OPA 03, OPA 08 and OPA 09) were selected based on their reproducibility and demonstration of polymorphism. OPA 03 amplified most of the samples tested whereas OPA 08 and OPA 09 amplified 50% of the samples. RAPD bands ranged from 180 bp to 2000 bp. RAPD profiles of C. mopane (sensu lato) with three random primers showed few polymorphisms. Individual trees of different ecotypes show similar RAPD banding pattern, instances were found where trees of the same ecotype showed different bands. The total character difference based on presence and absence of bands revealed both variability and similarity of C. mopane (sensu lato). Phylogenetic trees from individual primers and combined primers were constructed using Neighbour Joining and Parsimony analysis. The phylogenetic tree from the combined primers of bootstrap parsimony generated three clades with low and high parsimony bootstrap values. The first clade receives weak support (61%) while the second and third clades receive support of 90% and 70%, respectively. The other remaining entities collapsed resulting in basal polytomy. The third clade shows some members of Alba (Alba 11 Phala, Alba 1 Phala and Alba 7 Musina) grouped together. The overall results of C. mopane (sensu lato) show high (84.1%) genetic similarity. No ecotypic marker was obtained. Most of the ecotypes have not diverged genetically far from one another or from the parental material (Mopane – sensu stricto). The genetic results partially support the perceived morphological differences. In this study the RAPD technique has established its value as an additional tool to express the genetic variability in C. mopane (sensu lato).
The National Research Foundation

Thesis (MFor (Forest and Wood Science))--University of Stellenbosch, 2009.
The aim of this study was to develop biomass prediction models for the determination of total aboveground biomass for mopane at three (3) study sites in Botswana. Thereafter, based on the pooled data from the three (3) study sites, recommend one cross-site biomass prediction model that could be used for the indirect estimation of the total aboveground biomass for mopane in Botswana. All the data were collected by destructive sampling from three (3) study sites in Botswana. Stratified random sampling was based on the stem diameter at breast height (1.3 m from the ground). A total of 30 sample trees at each study site were measured, felled and weighed. The 30 sample trees were distributed equally between six DBH classes (Five sample trees per DBH class). Thereafter, using the data from these sample trees, site-specific biomass prediction models for the indirect estimation of total aboveground biomass for mopane were developed as a function of the following independent variables: stem diameter at 0.15 m from the ground; stem diameter at 1.3 m from the ground; stem diameter at 3 m from the ground; crown diameter; and total tree height. The data from the sites were pooled together to develop cross-site biomass prediction models as a function of the given independent variables. The biomass prediction model that provided the best fit at Serule was a linear equation estimated by means of the stem diameter at 1.3 m, while in Sexaxa the biomass prediction model that provided the best fit was estimated by means of the stem diameter at 0.15 m. The biomass prediction model that provided the best fit at the Tamacha site was estimated by means of the stem diameter at 1.3 m. On the basis of the collected data, cross-site biomass prediction models were developed. The cross-site biomass prediction model that provided the best fit was developed from the stem diameter at 1.3 m. This relationship was adopted as the prediction model for the indirect biomass estimation of Colophospermum mopane (mopane) in Botswana.

Thesis (MScConsEcol)--University of Stellenbosch, 2004.
ENGLISH ABSTRACT: The Mopane woodlands are some of the most economically and ecologically important vegetation types of southern Africa, providing an array of services and products for sustaining livelihood of local communities in dry and low lying areas. Although Mopane woodlands, like other African savannas, have received attention in the last decades, few studies were carried out using an integrated approach that combines socio-economic and environmental considerations. The aim of this study was to document the impact of harvesting woody resources in order to recommend ways of meeting ecological and economic objectives for sustainable use of communal resources in a rural community in the Mahel area, Mozambique. This was achieved by looking at the pattern of species composition, resource availability and dynamics of the woody vegetation and how the woodland is used. The study found that woodland resources in the area have a promising potential. Local communities who also recognised the crucial importance of these resources for their livelihood corroborated this. Thus, conservation measures are needed because the current unsustainable utilisation of the resources may lead to degradation of the woodland resource base. The species richness and diversity of the vegetation appeared to be influenced by a number of ecological and anthropogenic factors, but soil characteristics are the most important determinant of distribution and composition of the Mopane and Acacia woodlands in Mahel. The harsh environmental conditions on hard clay soils lead to dominance of over 80% of the Mahel area by Colophospermum mopane. There was evidence of high variation of species richness per plot at a distance from the villages. On the other hand species diversity near the villages was higher because of human activities. Colophospermum mopane formed mono-specific stands far from the villages. One of the most important aspects of the study is the invaluable contribution of baseline information for long-term studies for biodiversity assessment and monitoring of vegetation changes caused by impact of harvesting in the Mopane woodland. The availability of woody resources in the Mahel area was higher in Mopane woodland (937 stems ha-I) than in Acacia woodland (271 stems ha -1). The population structure of most tree species was shown to be stable in Mopane woodland. Therefore, sustainable harvesting in the woodland for firewood, construction material and poles, other than charcoal production could be encouraged. The preference across use types and species depended mostly on availability of resources in the woodland. Colophospermum mopane was the species with highest multiple use, including for firewood, charcoal, construction material, fencing poles and edible caterpillars. Local people perceived that crop production was a more important source of benefits for their livelihoods than cattle farming, woodland use and cash income. Application of strategic management planning is crucial in the Mahel area. This will require a suitable zoning scheme for appropriate use of the woodland resources and conservation of the vegetation as a guarantee for sustainable development of the local communities.
AFRIKAANSE OPSOMMING: Mopanie bosveld is een van die mees ekonomies en ekologies belangrike plantegroei tipes en voorsien 'n reeks dienste en produkte wat bydrae tot die lewensonderhoud van plaaslike gemeenskappe in die droeë en laagliggende dele van Suider Afrika. Alhoewel Mopanie bosveld, soos ook ander savanna tipes in Afrika, in die afgelope dekades aandag geniet het, is daar 'n tekort aan studies wat sosio-ekonomiese, sowel as omgewingsaspekte, integreer en aanspreek. Die doel van die studie was om die impak van oes en benutting van houtagtige hulpbronne te dokumenteer en sodoende aanbevelings te maak aangaande die ekologiese en ekonomiese aspekte van die volhoudbare benutting van gemeenskaplike hulpbronne in die Mahel gebied, Mosambiek. Dit is gedoen deur ondersoek in te stel na die patroon van spesie samestelling, die beskikbaarheid en gebruik van bosveld hulpbronne en die dinamiese prosesse van die houtagtige plantegroei. In die studie is gevind dat daar belowende potensiaal in die gebruik van die houtagtige hulpbronne in die studiegebied, opgesluit is. Die bevinding is bevestig deur die plaaslike gemeenskappe wat die belangrikheid van die hulpbronne in hul lewensonderhoud herken. In die lig van die huidige onvolhoudbare verbruik van die hulpbron, is maatreëls vir die bewaring hiervan nodig om moontlike oorbenutting van houtagtige hulpbronne te voorkom. Dit wil voorkom asof die spesierykheid en diversiteit deur 'n aantal antropogeniese faktore beinvloed word, maar grondeienskappe is die belangrikste faktor wat die verspreiding en samestelling van Mopanie en Akasia bosveld in die Mahel, bepaal. Die ongunstige omgewingstoestande op harde, klei grond, lei daartoe dat tot 80 % van die Mahel gedomineer word deur Colosphospermum mopane. Daar was verder aanduidings van hoër spesierykheid per plot soos daar van plaaslike nedersettings wegbeweeg word. Daar was egter 'n hoër spesiediversiteit nader aan nedersettings, as gevolg van menslike aktiwiteite. Daar was 'n tendens vir Colosphospermum mopane om mono-spesifieke opstande met groter afstand van nedersettings te vorm. Een van die mees belangrike aspekte van die studie is die bydrae wat dit lewer tot grondbeginsels vir langtermyn studies, wat fokus op die impak van menslike gebruik van Mopanie bosveld op die biodiversiteit en plantegroeisamestelling van die hulpbron. Die beskikbaarheid van houtagtige hulpbronne was hoër in die Mahel Mopanie bosveld (937 stamme ha-I) as in Akasia bosveld (271 stamme ha-I). Daar is gevind dat die populasiestruktuur, sowel as regenerasie van die populasie, stabiel is in Mopanie bosveld. Derhalwe kan benutting van die bosveld vir vuurmaakhout (uitsluitende charcoal) en boumateriaal aangemoedig word. Die voorkeur van sekere spesies en aanwending vir sekere gebruike het meestal afgehang van die beskikbaarheid van die verkillende hulpbronne in die bosveld. Colosphospermum mopane is die spesie wat die meeste aangewend is vir gebruik vir onder andere, vuurmaakhout, charcoal, boumateriaal, heining pale en die voorsiening van eetbare ruspus. Daar is verder bevind dat die plaaslike inwoners gewasproduksie as 'n belangriker ondersteuningsfaktor vir lewensonderhoud sien as lewendehawe produksie, bosveld benutting en kontant inkomste. Die toepassing van strategiese bestuursbeplanning is van kardinale belang in die Mahel. Dit sluit die ontwikkeling van 'n sonerings skema in, om die toepaslike gebruik van bosveld hulpbronne en die bewaring van die plantegroei te verseker vir die toekomstige volhoudbare gebruik van die hulpbron deur plaaslike gemeenskappe.

Background : The recorded history of veld burning in the Kruger National Park (KNP) started with the appointment of Colonel James Stevenson-Hamilton as warden of the Park (then the Sabie Game Reserve) in July 1912 and can be divided into five periods: From 1912 to 1926, a haphazard, and indecisive burning policy was practiced, mainly due to the perception that fire was unfavourable for the environment and because the means to combat veld fires were very meagre. From 1926 to 1948, in which period it was realized that fire was not only unavoidable over a large area such as the KNP, but also actually desirable, necessary and beneficial when applied with circumspection. During this period the capability to successfully introduce and apply a definite fire policy did not exist. From 1948 to 1956, prescribed burning was not practiced, but a network of graded firebreaks was being established (to create burning blocks), and wild fires were actively combated. From 1957 to 1993, during which period a definite prescribed burning policy was practiced, amended several times, but basically consisting of a triennial rotational system where blocks were burned by management. All fires of non-management ignition sources were combated. From 1993 to the present, when a policy of allowing lightning-ignited fires to burn freely was introduced, and fires of human origin were suppressed. The shift away from a rigid prescribed burning programme was because of the concern that the dominance of grass species characteristic of over utilised veld was a result of too frequent burning (Potgieter, 2001). Lightning fires probably played just as an important role in shaping African savanna in pre-industrial times as anthropogenic fires caused by preindustrial man. The role of post-industrial man as far as its influence on the creation of savanna is concerned is probably negligible, but significantly important in the role of maintaining savanna, although probably not more so than that of lighting fires. Fires caused by postindustrial man becomes suspect as far as the creation of savanna is concerned, because instead of the mere burning of the veld for the pure reasons of survival as practiced by pre-industrial man, a measure of commercialism crept in (Potgieter, 2001). Fire management of the KNP in pre-industrial times can be regarded in the same light as that of post-industrial times. Although the motive for burning the veld in the KNP was beyond reproach, the underlying reasoning was not. Managers’ thinking was geared towards preventing so called “devastating fires”, laying to waste large areas of the Park, not realising that this was in actual fact nature going about its business in this ecosystem. They therefore devised a system of firebreak roads, which was gradually extended to the extent that we now have more than 4000 km roads that must be maintained. This was all in the cause of preventing or managing lightning and arson fires. Given the above, a revision of the veld fire policy was extremely necessary. The mission statement hammered out during the revising process in 1993 underscored and supported the proposal put forward in 1992, that lightning fires should be recognised as a legitimate and completely natural phenomenon in the Lowveld ecosystem. This had to be weighed against the prevailing practice of combating all fires caused by lightning and non-management anthropogenic sources of fire. The essence of this policy would therefore be to allow lightning-fires to burn to their full extent i.e. if vegetation conditions (available biomass) are such that large areas will burn, then such burns will be permitted to proceed to their full extent with the provision that no more than 50% of the management unit will be allowed to burn out (no matter what the ignition source) in a specific fire season (Potgieter, 2001).

Abiotic and top down control hypotheses do not adequately explain the fine scale distribution patterns of shrub and tree Colophospermum mopane (Caesalpinioideae). Genetic distinctiveness between growth forms is investigated as an alternative hypothesis. Tree and shrub C. mopane from the riparian and inland savanna zones were sampled at four sites in the northern Kruger National Park. Molecular DNA sequences were obtained for four plastid and one nuclear region, and the inter simple sequence repeat (ISSR) technique used to fingerprint individuals. Very low levels of sequence divergence were observed. The ISSR technique revealed no genetic structure between plants when grouped by growth form or by habitat in an analysis of molecular variance (AMOV A). Soil profile and xylem pressure potential data also did not explain the distribution of growth forms. A principle component analysis and a discriminant analysis of five leaf and branching characters identified a significant difference in the shape of shrub and tree C. mopane leaves. It is concluded that the C. mopane growth forms are not genetically distinct and that their fine scale distributions may be due to top down controls such as large mammals and fire.

Thesis ( M.Sc. (Biodiversity)) --University of Limpopo, 2007
This dissertation reports on the results of field (Letsitele area) and laboratory investigations on the biology of Arytaina mopane, its ecological role as well as its physiological influences on the host plant Colophospermum mopane. The work is divided into three sections. Section one describes the various aspects of the biology of A. mopane, which includes the morphology of the eggs, nymphs and adults including the behaviour of nymphs and adults. Damage caused to the host plant by infestation as well as predation of A. mopane is discussed. Eggs are randomly laid on green and senescent C. mopane leaves, very often in clusters and along the veins. The eggs are black and conical in shape with a reticulate-sculptured membrane surrounding each. Each egg has a pedicel at the apical end and a filament at the basal end. An egg is not attached by a pedicel (contrary to the literature) but glued to the leaflet surface. Arytaina mopane exhibits an incomplete metamorphosis with the life cycle consisting of an egg, 5 nymphal instar and an adult. The five nymphal stages differed only in size and minor morphological features except for development of wings. Wingpad development is prominent from the third instars onwards. Nymphs construct scutcheon-like encrustations, commonly known as lerps over their bodies, which partly protect them from enemies and desiccation. Lerps covered only about 0.2% of the adaxial leaflet surface, where they were more common. Nymphs feed by piercing through the epidermal cells into the vascular bundle tissue of the leaflet with their stylet to reach the phloem sap. Feeding damage by nymphs results in black and reddish-brown spots on the leaflet surface. Two forms of nymphs that varied in colour and abdominal markings were identified, that could either be two different female morphotypes of the species, gender variation or natural variation. When not feeding, adults rest almost motionless on the leaflet or petiole with their stylet withdrawn and wings folded. Adults prefer walking or crawling to flying between v leaflets but sometimes jump when disturbed. When violently disturbed adults did fly short distances and returned to settle on a leaf of the same tree. The mean adult body length is 3.5 mm. In the laboratory, the life span of adults ranged between 5 and 8 days. Predators include birds such as the Red winged starling (Onychognathus morio) and Tawnyflanked prinia (Prinia subflava), the Painted reed frog (Hyperolius marmoratus taeniatus), the larvae of the Brown lacewing (Neuroptera: Hemerobiidae), a suspected Coccinellid beetle, and ants belonging to the genus Crematogaster. The second section reports on the physiological influences in terms of the chemical composition of lerps and the mineral content of both infested and uninfested C. mopane leaves. Lerps, infested and uninfested C. mopane leaves were tested for carbohydrate and mineral contents. The carbohydrate constituent of lerps and leaves (infested and uninfested) was sugar in the form of glucose, fructose and raffinose. Infested leaves contained significantly higher amounts of the macro elements calcium and magnesium than uninfested leaves. The uninfested leaves in contrast had significantly higher amounts of nitrogen, potassium, iron and copper. The ecological role of the infestation on C. mopane is reported in section three. Colophospermum mopane leaves at certain times of the year are known to have high tannin levels, which presumably results in bitter tasting leaves. The sweet encrustation (lerp) of A. mopane, apart from possibly reducing this bitter taste of the senescent leaves, raises the energy content by adding to the glucose and fructose levels of the leaves. This could consequently increase C. mopane’s browsable potential to game and wild animals during autumn. This could have an important impact on the game industry of the Limpopo and Mpumalanga Provinces of South Africa.
National Research Foundation, and the Discipline of Botany, University of Limpopo, Turfloop Campus

Thesis (Ph. D. (Botany)) -- University of Limpopo, 2020
Colophospermum mopane (Benth.) J. Léonard, commonly known as mopane, is a dominant tree or shrub in the mopane woodland. It is distributed in the low-lying areas of southern Africa’s savannas. Mopane maintains its foliage well into the dry season, and thus provides nutritional forage for browsers such as Tragelaphus strepsiceros, commonly known as the greater kudu. Despite its wide distribution and value as a source of forage for browsers, especially during the dry season, knowledge of the effect of browsers on mopane leaf quality is limited. There is also inadequate knowledge of the diet composition of the greater kudu during different seasons in the mopane woodland. Such information is important for proper management of browsers in the mopane woodland. As a result, a field experiment was conducted at Musina Nature Reserve, Limpopo Province, South Africa to determine the effect of pruning on mopane leaf phenology, production, macronutrients, trace elements and secondary metabolites. Pruning was conducted to simulate the effect of browsing by large herbivores such as the greater kudu on mopane leaf quality. In addition, rumen content analysis of greater kudu was conducted in order to quantify the amount of mopane and other plants browsed during the dry and wet seasons. Collected datasets were analysed using descriptive and inferential statistics. A two-tailed Mann-Whitney U-test was used to test the effect of pruning on mopane leaf phenology and production. The effect of pruning on the monthly concentration of macronutrients, trace elements and secondary metabolites was tested using a two-tailed t-Test: Two-Sample Assuming Equal Variance. The seasonal and annual effect of pruning on the concentration of macronutrients, trace elements and secondary metabolites was tested using One-Way Anova. Rumen datasets were analysed using the Pearson Correlation Coefficient. This study found that the rate of leaf phenology and production, including the concentration of certain macronutrients (Ca, K, N, P, S, Cl, Na, protein and fibre), trace elements (Fe, Mn, Mo, Cu, Zn and Se) and secondary metabolites (TP, CT and PPT) increased during leaf flush in October and then declined as the leaves ii matured and aged. However, the concentration of selected macronutrients (Mg and NO3) and trace elements (B, Co and F) increased when the leaves reached maturity in June, particularly during the leaf senescence stage, and declined thereafter. The concentration of macronutrients, trace elements and secondary metabolites between the control and pruned trees was statistically insignificant at P>0.05 for most samples. This study further showed that C. mopane contributed most (47%) to the diet of the greater kudu during the dry season. Other important dry season browse plants were Dichrostachys cinerea (30%), Commiphora edulis (12%), Grewia bicolor (6%) and Combretum apiculatum (5%). However, when gender was considered, the diet of the female greater kudu during the dry season consisted mainly of C. mopane (71%) and D. cinerea (22%). The diet of the male greater kudu contained less C. mopane (33%), but similar proportions of D. cinerea (31%) and other browse species. However, during the wet season, the diet of the greater kudu was mainly composed of C. apiculatum (43%). Other wet season browse plant species were Sclerocarya birrea (24%), C. mopane (12%) and Senegalia nigrescens (8%), with the contribution of the remaining species to the diet being insignificant. The diet of the female greater kudu in the wet season consisted mainly of C. apiculatum (44%) and C. mopane (20%), while the diet of the male mostly contained S. birrea (38%) and C. apiculatum (34%). It is concluded that the concentration of macronutrients, trace elements and secondary metabolites in mopane leaves is not dependent on <10% pruning, but seems to be associated with leaf growth stages. It is further concluded that the concentration of nutrients and chemical compound in mopane leaves has implications on the diet composition of browsers such as the greater kudu in the mopane woodland. The dependency of the greater kudu on species such as C. mopane and C. apiculatum as main sources of browse indicates the importance of these species to the diet of the greater kudu in the mopane woodland.
Deutscher Akademischer Austausch Dienst (DAAD) , National Research Foundation (NRF) and University of Limpopo (Biodiversity Research Chair)

MSCAGR (Plant Production)
Department of Plant Production
Colophospermum mopane (Fabaceae), commonly known as mopane tree, is an indigenous tree species in Southern Africa, often being the dominant species in semi-arid areas. It plays an integral part in the improvement of communities’ livelihoods when it is harvested for firewood and mopane worms which are edible insects are collected from the tree. Colophospermum mopane is host to many insects, among them Retroacizzia mopani, a leaf pest. Retroacizzia mopani produces lerps which are protective exudates that shield the insect from predation, but lerps also reduce the photosynthetic area of mopane leaves. This study aimed to determine the distribution of the African mopane psyllid, R. mopani and its natural enemies in the Tshikundamalema area, in Limpopo Province. The study assessed the presence of lerps on C. mopane, as well as determining the effect of site, tree height, tree density, tree position, branch size and neighbouring trees on R. mopani infestations at three sites. Sample of leaves infested with R. mopani were collected at six different sites and reared in the laboratory to determine the prevalence of R. mopani natural enemies and the levels of parasitism. The site, tree density, tree position, and branch size had an effect on the R. mopani infestations. The results showed that as the tree density, tree height and branch size increased, R. mopani infestation also increased. Neighbouring trees had no effect on R. mopani infestations. Trees found at the edge of the forest were more heavily infested compared to those that were inside the forest. All the three sites had low levels of parasitism by the natural enemy, Psyllaephagus arytainae Prinsloo. This indicates that P. arytainae has little effect on population dynamics of the psyllids.

Mopane (Colophospermum mopane) woodlands are a source of valuable resources that contribute substantially to rural economies and nutrition across Southern Africa. However, a number of factors such as over-harvesting and climate change have brought the sustainability of the mopane woodland resources into question. Insect defoliation remains a major factor contributing to the depletion of woodland resources in rural areas resulting in low vitality and productivity of the woodland. Conventional methods (e.g. visual evaluation) have been used in monitoring insect defoliated areas in the past. These methods are costly and timeconsuming, because of the need to collect data immediately before and after an extreme event. In this regard, remote sensing techniques offer a practical and economical means of quantifying woodland degradation over large areas. Remote sensing is capable of providing rapid, relatively inexpensive, and near-real-time data that could be used for monitoring insect defoliation especially in semi-arid areas where data collection may be difficult. The present study advocates the development of techniques based on remotely sensed data to detect and map defoliation levels in Mopane woodland. The first part of the study provides an overview of remote sensing of insect defoliation, the implications for detecting and mapping defoliation levels as well as the challenges and need for further research especially within Mopane woodland. Secondly, the study explored whether Mopane species can be discriminated from each of its co-existing species using remote sensing. This was done as a prerequisite for classifying defoliation on mopane trees. Results showed that, with limited training samples, especially in semi-arid areas, Mopane trees can be reliably discriminated from its co-existing species using machine learning algorithms and multispectral sensors with strategic bands located in sensors such as RapidEye. These positive results prompted the need to test the use of ground based hyperspectral data and machine learning algorithm in identifying key spectral bands to discriminate different levels of insect defoliation. Results showed that the random forest algorithm (RF) simplified the process and provided the best overall accuracies by identifying eight spectral wavelengths, seven of which belongs to the red-edge region of electromagnetic spectrum. Furthermore, we tested the importance of the red-edge region of a relatively cheaper RapidEye imagery in discriminating the different levels of insect defoliation. Results showed that the red-edge region played an important role in mapping defoliation levels within Mopane woodland with NDVI-RE performing better than the traditional NDVI. Thirdly, the study tested the reliability and strength of the internal validation technique of RF in classifying different defoliation levels. It was observed that the bootstrapping internal estimate of accuracy in RF was able to provide relatively lower error rates (0.2319) for classifying a small dataset as compared to other validation techniques used in this study. Moreover, it was observed that the errors produced by the internal validation methods of RF algorithm was relatively stable based on the confidence intervals obtained compared to other validation techniques. Finally, in order to evaluate the effects of insect defoliation on the biophysical properties of mopane canopies at different defoliation levels, the study estimated leaf area index (LAI) of different defoliation levels based on simulated data. This was done using PROSAILH radiative transfer model inverted with canopy spectral reflectance extracted from RapidEyeRapidEye imagery by means of a look-up-table (LUT). It was observed that the significant differences exist between the defoliation levels signifying reduction in the LAI as a result of the defoliation. Furthermore, results showed that the estimated LAI was in the range of those reported in literature. The NDVI-RE index was the most strongly correlated with the estimated LAI as compared to other variables (RapidEye bands and NDVI). Overall, the study demonstrated the potential of remote sensing techniques in discriminating the state of Mopane woodland after insect defoliation. The results are important for establishing an integrated strategy for managing defoliation processes within Mopane veldt, thereby satisfying both the needs of local populations for Mopane trees and the worms.
Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.