Landscapes of the Kruger National Park

Knowledge on the abiotic and biotic components of the Kruger National Park (KNP) system has increased to such an extent, that it was possible to zonate the KNP into landscapes. A landscape was defined as an area with a specific geomorphology, climate, soil and vegetation pattern together with the associated fauna. On this basis 35 landscapes were identified and described in terms of the components mentioned in the definition. The objective of classification is that future management should be based on these landscapes. Relevant management considerations may change, but the landscape a@ a basic functional unit should not be negotiable

Rainfall patterns in the Kruger National Park

The available rainfall data for all the recording stations in the Kruger National Park are presented. The average annual rainfall was calculated for each station and this served as basis for compiling a rainfall map for the region. The cyclic nature of the annual rainfall as well as the rainfall distribution within cycles were investigated and a prediction made of expected future rainfall

Veldbrandnavorsing in die Struikmopanieveld van die Nasionale Krugerwildtuin

Die geskiedenis van veldbrand en die ontwikkeling van die huidige brandbeleid in die Nasionale Krugerwildtuin, Republiek van Suid-Afrika, word bespreek. Aandag word gegee aan die ligging en uitleg van die brandproefherhalings in die struikmopanieveld. Die metode van opname van die houtagtige komponente en die veldlaag word bespreek, sowel as die kriteria wat gebruik is in die vergelyking tussen brandbehandelings. 'n Fitososiologiese tabel van die verskillende persele is opgestel met spesifieke verwysing na die verskille in grondsoorte en hoe dit die floristiese samestelling bei'nvloed. Uit die resultate wat verkry is, is dit duidelik dat meer frekwente brande 'n nadelige invloed op die veldlaag het. Dit hang egter grootliks at van die seisoen van diejaar waarin gebrand word, sowel as die reenval en gepaardgaande opbou van brandbare materiaal. Brande in Augustus, Oktober en Desember is strawwer en rig meer skade in die veldlaag aan. In 'n nat siklus word die houtagtige komponent beter beheer deur 'n meer frekwente brand, maar as dit in 'n droe siklus toegepas word, kan dit lei tot bosindringing. 'n Oorwegende gevolgtrekking van hierdie studie is dat 'n brand* beleid wat nie daarop ingestel is om die natuurlike regime sover moontlik te simuleer nie, tot veldagteruitgang kan lei. Veld fire research on the mopani shrubveld of the Kruger National Park. The history of veld burning and the development of the current burning policy in the Kruger National Park, Republic of South Africa, are discussed. Attention is given to the siting and lay-out of replications of the experimental burning plots in the northern mopani shrubveld. The method used for syurveying the woody and herbaceous components and the criteria used for comparing different burning treatment are explained. A phytosociological table of different plots is presented with special reference to differences in soil types and its influence on floristic composition. The results obtained show that more frequent burns have a detrimental effect on the herba-ceous vegetation. This is primarily dependent on the amount of accumulated fuel which in turn is influenced by the season and amount of rainfall. The August, October and December burns are more severe and cause more damage to the herbaceous field layer. In a wet cycle better control of the woody components is obtained with more frequent burns, but when applied during a dry cycle it may lead to bush encroachment. A major conclusion is that a burning policy which is not aimed at simulating the natural regime as far as possible, may cause deterioration of veld conditions

Sperm storage and duration of fertility in female ostriches (Struthio camelus)

CITATION: Malecki, I. A. 2004. Sperm storage and duration of fertility in female ostriches (Struthio camelus). South African Journal of Animal Science, 34(3):158-165.The original publication is available at https://www.sasas.co.zaIn two experiments, one carried in South Africa and the other in Western Australia, the duration of sperm storage and the fertile period following separation of sexes were investigated by egg break-out and by counting the sperm in the perivitelline membrane (spermOPVL) above the germinal disc (GD) region. Fertilisation status was determined by the appearance of the GD. The perivitelline membrane above the GD was collected to count sperm under fluorescence following staining with 4′,6′-diamidino-2-phenyindole (DAPI). In both experiments, after the males were removed, the rate of lay declined by about 50% within a week. Following separation, spermOPVL were detected for up to four weeks and fertilised eggs were laid for nearly the same duration. The loss of sperm followed an approximately logarithmic function and sperm numbers declined at rates similar to that of the turkey. Since the duration of sperm storage was longer than indicated by clutch duration, ostrich clutch size might be larger than reported or female ostriches might store sperm for up to two clutches. Fertilisation rate in ostrich eggs is high because most eggs contain excessive numbers of sperm and very low numbers of sperm appear sufficient to achieve fertilisation.https://www.sasas.co.za/journals/sperm-storage-and-duration-of-fertility-in-female-ostriches-struthio-camelus/Publisher's versio