Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
The 5th International Wildland Fire Conference Sun City, South Africa 9–13 May 2011 The Mun-Ya-Wana Private Game Reserve, South Africa – a leader in using a Decision Support System for Prescribed Burning Winston S.W. Trollope1, Lynne A. Trollope1, Simon J. Naylor2, Ross R. Goode3, Philip de Bruyn4 , Stanley Cheswick 5 , Christian H. Schütte6 1 Working on Fire International, 38 Durban Street, Fort Beaufort, 5720, South Africa: [email protected]; Reserve Manager, Beyond, Phinda, Mun-Ya-Wana Game Reserve, Hluhluwe, South Africa: [email protected]; 3 Consultant, Mun-Ya-Wana Game Reserve, Hluhluwe, South Africa: [email protected]; 4 Assistant Reserve Manager, Beyond, Forest-,Vlei Lodge and Homestead, Phinda Private Game Reserve, Hluhluwe, South Africa: [email protected]; 5. Reserve Manager, Zuka, Mun-Ya-Wana Game Reserve, Hluhluwe, South Africa: [email protected]; 6 Owner, Bumbeni, Mun-Ya-Wana Game Reserve, Hluhluwe, South Africa: [email protected] 2 Abstract The assessment of range condition is a key requirement for the successful use of prescribed burning in wildlife management systems. The Mun-Ya-Wana Private Game Reserve comprising the Phinda, Zuka and Bumbeni sections, are leaders in Kwa-Zulu Natal, South Africa, in the use of range condition data for managing the rangelands on the Reserve. Prescribed burning is one of the essential range management practices used for improving the productivity and biodiversity of the grass sward and for controlling the encroachment of bush species like Dichrostachys cinerea. This is achieved through the use of a decision support system involving ecological criteria based on the condition of the grass sward. For this purpose the different species in the grass sward are divided into three ecological categories based on their reaction to grazing intensity viz.: Decreaser species – palatable and productive grass species that decrease when rangeland is under- or over-grazed; Increaser I species – less palatable and productive grass species that dominate when rangeland is under- or selectively grazed; Increaser II species – less palatable and productive pioneer grass species that increase when rangeland is over-grazed. Using this classification prescribed burning is not applied if the grass sward is in a pioneer condition dominated by Increaser II grass species caused by overgrazing. This is in order to enable the sward to develop to a more productive and resilient stage dominated by Decreaser grass species. Conversely when the grass sward is either under or selectively grazed dominated by Increaser I species burning is applied to encourage and increase the better fire adapted and more productive and palatable Decreaser grass species. Finally controlled burning is applied when the grass sward has become overgrown and moribund as a result of excessive self-shading, -1 generally when the standing crop of grass is >4 000 kg ha . A range condition monitoring program was initiated on the Reserve in 1998 and using data from the annual assessments together with the above criteria for prescribed burning, the overall condition of the rangelands on the Reserve have improved by approximately 30% in terms of the grazing capacity and dominance of productive and palatable grass species for utilization by wild ungulate species. Key Words: fire management, prescribed burning, range condition, wildlife management 1. Introduction The assessment of range condition is a key requirement for the successful use of prescribed burning in wildlife management systems. The Mun-Ya-Wana Private Game Reserve, 23 453 hectares in extent and comprising the Phinda, Zuka and Bumbeni sections, are leaders in South Africa in the use of range condition data for managing the rangelands on the Reserve. Prescribed burning is one of the essential range management practices used for improving the productivity and biodiversity of the grass sward and for controlling the encroachment of bush species like Dichrostachys cinerea. This is being achieved through the use of a decision support system involving ecological criteria based on the condition of the grass sward. In addition Mun-Ya-Wana is unique in that it is a highly successful partnership of rural communities and commercial enterprise, with the Phinda portion of the Reserve being owned by the Nqobogazi and Mduku rural Zulu communities, who lease it to the & Beyond commercial enterprise of shareholders. The Reserve is successfully managed for wildlife conservation and tourism resulting in socio-economic benefits to the communities and the maintenance of ecosystem services for all concerned. The objective of this paper is to provide an overview of the decision support system for managing the prescribed burning program which is based on the assessment of the condition of the rangelands on the 2 Reserve. This has resulted in significant ecological and financial benefits to the owners of the Mun-Ya-Wana Private Game Reserve. Insert Fig 1 Figure 1: Shareholders in the Mun-Ya-Wana Private Game Reserve located in the Zululand region of the KwaZulu Natal Province in north eastern South Africa. 2. Vegetation, Soils and Climate Mun-Ya-Wana has a unique suite of vegetation types including rare sand forest growing on the old Saint Lucia dune formations. According to Acocks (1988) the vegetation comprises Coastal Forest and Thornveld that includes Zululand Palm Veld and Zululand Thornveld, the latter occupying the escarpment of the first coastal plateau of the eastern slopes and tops of the Lebombo mountain range. Mucina & Rutherford (2006) provide a more comprehensive description of the vegetation classifying it as part of the Savanna Biome comprising the Zululand Lowveld No SVI 23 and Western Maputaland Sandy Bushveld No SVI 19. The former vegetation type comprises extensive flat or slightly undulating landscapes supporting various bushveld units ranging from dense thickets of Dichrostachys cinerea (sickle bush) and Acacia species to park-like savanna with broadleaved open bushveld characterised by Sclerocarya birrea (marula) and Acacia nigrescens (knobthorn). The herbaceous layer comprises tall grassveld types that include Themeda triandra, Panicum deustum, Sporobolus pyramidalis, Schizachyrium sanguineum, Setaria incrassata, Trachypogon spicatus and Tristachya leucothrix. The edaphic environment includes black-clay and duplex soils derived from a variety of sediments of the Dwyka, Ecca, Beaufort and igneous rocks of the Lebombo group and well drained soils occurring on stony slopes. The other vegetation type, the Western Maputaland Sandy Bushveld, is also located east of the Lebombo mountain range and comprises short bushlands and wooded grasslands occurring on mid- and lower midslopes of ancient coastal dune cordons. The underlying geology comprises carbonate rich sandy dune cordons and siltstones with well drained mesotrophic soils with a low clay content. Following intensive grass and tree and shrub field surveys at 44 sample sites by the Mun-Ya-Wana ecology section of the Reserve the vegetation was classified into the following homogeneous vegetation units (HVU’s) for range management purposes. This was done specifically for the application of a prescribed burning program in those vegetation types where fire is an essential and important range management practice – see Figure 2. Insert Fig 2 Figure 2: Classification of the vegetation into different homogeneous vegetation units (HVU’s) on the Mun-Ya– Wana Private Game Reserve. The climate of the Reserve is characterised by mild, frost free winters and hot, humid summers with mean daily 0 0 maximum and minimum temperatures exceeding 30 C in summer and 5 C in winter in this region of KwaZuluNatal province (Mucina & Rutherford, 2006). Detailed rainfall records for Mun-Ya–Wana for the period 1995 to 2009 are presented in Figure 3. Insert Fig 3 Figure 3: Mean monthly rainfall for the Mun-Ya-Wana Private Game Reserve recorded during the period 1995 to 2009. The mean annual rainfall for the period 1995 to 2009 was 776 mm with a coefficient of variation of 29% where the maximum and minimum annual rainfall recorded was 1195 and 354 mm respectively indicating the significant variability characterising the annual precipitation of the area. 3. Wildlife Ungulate Population With one of the management objectives of the Mun-Ya-Wana Private Game Reserve being to provide a competitive/high quality interpretive wildlife experience there is a diverse wild ungulate population of grazing and browsing ungulate species. An aerial census of the wild ungulate population is conducted annually and the estimated numbers for 2010 are presented in Table 1. Table 1: The number of different wild ungulates estimated with an aerial census on the Mun-Ya-Wana Private Game Reserve during 2010. Bulk Grazers No. Buffalo 350 Elephant 88 Concentrate Grazers Blue Wildebeest Bush Pig No. 500 50 Browsers Black Rhino Bushbuck No. Mixed Feeders No. 27 Impala 2000 1 Nyala 4000 Overall Total 3 Zebra Total 400 838 Mountain Reedbuck Steenbok 50 Giraffe 150 4 50 Waterbuck Warthog 25 1000 Grey Duiker Kudu Red Duicker White Rhino Hippopotamus 140 50 1819 250 200 651 6000 9308 4. Assessment and Monitoring of Range Condition for Prescribed Burning Following a series of lectures presented in 1998 by the senior author at the Southern African Wildlife College on the assessment of vegetation in African savannas for wildlife management, the ecologist for Mun-Ya-Wana who attended the course, requested advice. Recommendations were provided on the assessment and monitoring of range condition for prescribed burning for maintaining and improving range condition, and also for combating and preventing bush encroachment, a major problem on the Reserve. Sample sites representative of the different homogeneous vegetation units were identified throughout the Reserve. The assessment and monitoring of the vegetation using rapid, reliable and simple techniques for assessing range condition (Trollope & Potgieter, 1986; Trollope, 1990), was initiated in order to collect appropriate ecological data on which to base management decisions. Generally botanical survey methods are complicated and time consuming and do not lend themselves to monitoring the condition of rangeland for management purposes. Annual vegetation monitoring has continued to date (13 years) and the data are analysed to provide a decision support system for the application of ecologically appropriate burning treatments for improving and/or maintaining the condition of the rangelands on the Reserve. This has resulted in a significant improvement in the overall condition of vegetation on Mun-YaWana and the regeneration of areas of degraded farmland, previously used to grow crops like pineapples, sisal and cotton, to productive savanna vegetation best suited for supporting a wide range of wildlife communities. The following range assessment and monitoring program is being followed on Mun-Ya-Wana as a means of providing the necessary ecological data for managing the prescribed burning program on the Reserve. The necessity for rangeland to be burnt or not depends upon its ecological status and physical condition. Generally the condition of the grass sward determines whether rangeland should be considered for burning as this component of the vegetation reflects the ecological status of the ecosystem and the presence of or its ability to produce adequate grass fuel to carry and support a fire. Quantitative techniques have been developed to assess the condition of the grass sward in relation to prescribed burning. The first technique involves determining the condition of the grass sward in terms of its botanical composition, ecological status and basal cover and involves classifying the different grass species into different ecological categories according to their reaction to a grazing gradient i.e. from high to low grazing intensities as follows: DECREASER SPECIES - Grass & herbaceous species which decrease when rangeland is under or over grazed; INCREASER I SPECIES - Grass & herbaceous species which increase when rangeland is under grazed; INCREASER II SPECIES - Grass & herbaceous species which increase when rangeland is over grazed. Simplified techniques based on key grass species that have a highly significant effect on the potential of the grass sward to produce grass fuel, have been developed in southern and east Africa (Trollope, 1983; Trollope & Potgieter, 1986; Trollope & Trollope, 1999). Using these techniques criteria have been developed and successfully used to decide whether rangeland in a particular condition should be considered for burning or not. The second technique involves estimating the grass fuel load using the Disc Pasture Meter developed by Bransby and Tainton (1977) and illustrated in Figure 4. Insert Fig 4 Figure 4: Disc Pasture Meter developed by Bransby & Tainton (1977) used to estimate grass fuel loads for prescribed burning on Mun-Ya-Wana Private Game Reserve. This technique involves relating the settling height of an aluminium disc dropped onto the grass sward to the standing crop of grass holding up the disc, expressed in kilograms per hectare. There is a simple relationship between the settling height and the standing crop of grass based on the fact that the more grass there is the higher off the ground the disc settles. This instrument has been successfully calibrated for much of the 4 grasslands and savannas in southern and east Africa and the calibration developed in the Kruger National Park in South Africa by Trollope & Potgieter (1986) is used for estimating grass fuel loads for prescribed burning on Mun-Ya-Wana. The prescribed burning program being used on Mun-Ya-Wana is known as the Range Condition Burning System and was developed from a fire research program that was initiated in South Africa in the Eastern Cape Province in 1968 and later extended to the Kruger National Park in 1982 and to East Africa in 1992 (Trollope, 1971; Trollope & Potgieter, 1985; Trollope & Trollope, 1999). It is based on empirical results and its appropriateness for use in wildlife areas is that it provides a practical means of improving and maintaining the species and habitat diversity of natural grassland and savanna ecosystems (Trollope, 1971; Trollope et.al. 1995). This is achieved by burning to remove moribund and/or unacceptable grass material, to create or maintain an optimum relationship between herbaceous and woody vegetation if necessary, and to encourage wildlife to move to less preferred areas in order to minimise the overutilization of preferred areas. The basic philosophy of the range condition burning system is that the use of fire to achieve specific management objectives must be based on the condition of the vegetation and its known reaction to the different components of the fire regime i.e. type and intensity of fire and season and frequency of burning. The following ecological criteria are used to apply a burning program that will achieve the overall management objectives of improving and maintaining species and habitat diversity in grassland and savanna ecosystems. If the grass sward is dominated by pioneer grass species (Increaser II species) like Aristida, Eragrostis, Sporobolus, Tragus and Enneapogon species the grassland or savanna should not be considered for burning as this treatment will maintain the grass sward in a pioneer condition characterised by a low diversity of perennial grass species. Conversely if the grass sward is dominated by either climax or subclimax grass species (Increaser I & Decreaser species) like Hyperthelia, Hyparrhenia, Themeda, Andropogon and Pennisetum species the grassland or savanna can be considered for burning provided it is in a moribund condition. These criteria are intended to maintain a high species diversity of perennial grass plants. If the grass fuel load is greater than 4 000 kg ha then the grass sward is in a moribund condition and should be considered for burning. When the grass sward is in this condition in savanna areas it will also be able to generate an intense enough fire to create or maintain an optimum relationship between herbaceous and woody vegetation if necessary. This criterion is intended to maintain the grass sward in a vigorous and palatable condition that will ensure an adequate flow of forage for grazing animals and provide adequate resistance to accelerated soil erosion. It also provides the means of manipulating the structure of savanna vegetation to promote or maintain habitat diversity. All wildfires initiated by unplanned ignition sources like lightning or other causes are allowed to burn freely if the condition of the grassland or savanna vegetation fulfils the ecological criteria, otherwise they must be extinguished as far as possible. This is because the effect of fire on grassland and savanna vegetation is similar irrespective of the source of ignition if burnt under the same conditions. To prevent inadequate supplies of forage being available for the ungulate population, limits are set on the overall size of area to be burnt in any one season. Since Mun-Ya-Wana is located in the moist savanna not more than 50% of the total area available for burning is burnt during a growing season. -1 The following fire regime was recommended and is being used on Mun-Ya-Wana to implement the prescribed burning program on the Reserve: Type Of Fire The designated areas to be burnt are ignited as normal perimeter ignitions involving the “block burning” of the selected areas of rangeland that qualify for burning. Point ignitions involving a “Patch Mosaic Burning System” are not used because of the high risk of “run-away” wild fires associated with this burning system. Fire Intensity Fire intensity is an important component of the fire regime that needs to be, and is varied according to the reason -1 -1 for burning. When burning to remove moribund and/or unacceptable grass material a cool fire of <1 000 kJ s m is recommended and can be achieved by burning when the air temperature is <20°C and the relative humidity >50%. When burning to restore the balance between herbaceous and woody vegetation as trees and shrubs -1 -1 have become too dense, it is necessary to apply an intense fire of >2 000 kJ s m . This can be achieved when -1 the grass fuel load is >4 000 kg ha , the air temperature is >25°C and the relative humidity is <30%. This will cause a significant topkill of stems and branches of trees and shrubs up to a height of 3 m and make the 5 vegetation more available for shorter browsing animal species. In all cases the wind speed should not exceed 20 -1 km h for safety reasons (Trollope, 1999). The selection of the appropriate weather conditions for applying the fire intensities applicable to the different reasons for burning can be easily achieved by using the South African Lowveld Fire Danger Index for prescribed burning (Heine, Heine & Trollope, 2008) i.e. low intensity fires for removing moribund material and high intensity fires for combating bush encroachment. Fire intensity can be manipulated by taking into account the weather conditions at the time of the burn, the fuel load and curing condition of the grass fuel i.e. what proportion of dry grass is in the grass sward. The Fire Danger Index is calculated by considering the combined effects of air temperature, relative humidity, wind speed and degree of curing of the grass fuel, estimated as the percentage dryness of the grass, at the time of applying the fire. Air temperature and relative humidity are plotted on a chart to estimate a Burning Index. The Burning Index is adjusted using a Wind Correction Factor and a Grass Curing Factor. Charts together with an easy equation are available to enable the range manager to quickly calculate the FDI and assess whether it is suitable for the current reason for burning. The guidelines for using different Fire Danger Indices for prescribed burning are presented in Table 2. Table 2: Fire Danger Rating System for Prescribed Burning In African Grassland & Savanna Ecosystems. Season of Burning Burning on Mun-Ya-Wana is restricted to when the grass sward is dormant in order to avoid any detrimental effects on the regrowth and basal cover of the sward. The burning window can extend over the entire dry season commencing in June but the actual timing of the fires is varied according to the reasons for burning. When burning to remove moribund grass material prescribed burns are applied at any time during the dormant season. Conversely when burning to combat or prevent bush encroachment fires are applied after July when the grass fuel moisture is at its lowest to ensure a high intensity fire. Frequency of Burning When burning to remove moribund and/or unacceptable grass material the frequency of burning depends upon -1 the rate at which the grass sward becomes moribund (Trollope, 1989) i.e. grass fuel load >4 000 kg ha . Therefore the frequency of burning depends on the rate at which the grass fuel load accumulates and is therefore variable and a function of the stocking rate of grazing animals and the amount of rainfall the area receives. When burning to combat or prevent bush encroachment the frequency of burning is variable and depends upon the stocking rate of browsing animals and/or the rate of regrowth of the trees and shrubs. 6 Post -Fire Grazing Management Grazing after burning in wildlife areas is difficult to control. In order to prevent overgrazing it is important to ensure that the burnt area exceeds the short term forage requirements of the grazing animals that are attracted to the highly palatable and nutritious regrowth that develops after a burn. To avoid this problem relatively large areas are burnt Mun-Ya-Wana at any one time i.e. > 500 ha. Another strategy that is used, is to apply prescribed burns at regular intervals throughout the duration of the burning window during the dormant season. This has the effect of attracting the grazing animals to the newly burnt areas after the different fires thereby spreading the impact of grazing over the entire burnt area and avoiding the detrimental effects of heavy continuous grazing after the burns. 5. Effects of the Range Condition Burning System on Range Condition The Range Condition Burning System has been implemented on Mun-Ya-Wana since 1998. Only since 2004 has the range condition monitoring program has adequately covered all the different Homogenous Vegetation Units (HV’s). Results will therefore only be presented for the effects of the burning program on the grass sward. The assessment of the condition of the tree and vegetation for browsing animals has been included in the monitoring of the vegetation on the Reserve since the recent development of a suitable survey technique for this purpose. Data will now be presented to reflect the effects of the burning program on the forage and fuel potential, dominance of palatable and nutritious Decreaser species and the basal cover of the grass sward. Forage Potential The forage production potential of the grass sward is represented by the Forage Score This is calculated from the production potential of the individual estimates of the palatability and production of the different grass species that are recorded in the botanical composition of the grass sward in the different HVU’s. The Forage Scores recorded in the different HVU’s on Mun-Ya-Wana are presented in Figure 5. Insert Fig 5 Figure 5: The forage potential of the grass sward estimated for the different Homogeneous Vegetation Units on the Mun-Ya-Wana Private Game Reserve in 2004 and 2010. Data presented as Forage Scores. The results in Figure 5 indicate that there has been a significant increase in the forage potential of the grass sward in the majority of the HVU’s on the Reserve except for the Sandveld Woodland. A statistical analysis of the Forage Scores for 2004 and 2010 showed that overall increase in the Forage Scores was highly significant (F = 6.80; DF = 62; P< 0.01). However, it must be born in mind that the forage potential in the Sandveld Woodland and Sand Forest is not influenced by the prescribed burning program because these HVU’s are seldom, or not intentionally burnt. However, the remaining HVU’s all qualify and are included in the vegetation units being burnt on Mun-Ya-Wana and therefore the improvement in the forage potential of the grass sward can be interpreted as an improvement in the condition of the rangelands as a result of the burning program being implemented through the use of the Decision Support System involved in the Range Condition Burning System. Decreaser Grass Species An important reason for the increase in the forage potential of the grass sward is the recorded increase in the frequency of highly palatable, productive and nutritious Decreaser grass species like Themeda triandra, Panicum maximum, Digitaria eriantha and Chrysopogon serrulatus. The frequency of Decreaser grass species recorded in the different HVU’s on Mun-Ya-Wana during 2004 versus 2010 is presented in Figure 6. Insert Fig 6 Figure 6: The percentage frequency of Decreaser grass species in the grass sward estimated for the different Homogeneous Vegetation Units on the Mun-Ya-Wana Private Game Reserve in 2004 and 2010. Data presented as percentage frequency. The results in Figure 6 show that there has been a marked overall increase in the percentage frequency of Decreaser grass species in the majority of the HVU’s on Mun-Ya-Wana recorded in 2010 compared to 2004 and again the overall increase is statistically significant (F= 4.47; DF = 63; P<0.04). As in the case of the forage potential the changes in the frequency of Decreaser grass species in the Sandveld Woodland and Sand Forest is not influenced by the burning program because these HVU’s are seldom, or not intentionally burnt. The one anomaly though is that while the forage potential in the Mixed Lebombo Woodlands showed an increase in 2010 the frequency of Decreaser grass species showed no significant change. This anomaly will be investigated in the future as this HVU constitutes a significantly major portion of Mun-Ya-Wana (17%). Again these results provide additional evidence of the beneficial effects the Decision Support System involved in the Range Condition Burning System is having on the condition of the rangelands on the reserve. 7 Grass Basal Cover A fundamentally important effect of the Range Condition Burning System is its effect on the basal cover of the grass sward as represented by the Point To Tuft Distances of the grass tufts. The results for this parameter are presented in Figure 7. Insert Fig 7 Figure 7: The Basal Cover of the grass sward estimated for the different Homogeneous Vegetation Units on the Mun-Ya-Wana Private Game Reserve in 2004 and 2010. Data presented as the point to tuft distance. The results in Figure 7 indicate that in all the different HVU's there was a marked decrease in the point To Tuft Distance recorded in 2010 compared 2004. The decrease was statistically highly significant (F = 41.17; DF = 62; P<0.01) and this result constitutes a marked improvement in the basal cover of the grass sward and therefore a significant decrease in the potential for accelerated soil erosion in the different HVU’s on the Mun-Ya -Wana Private Game Reserve. Again in terms of the effects of the burning program on the HVU’s that are regularly burnt this provides additional evidence of the significant effect that the Range Condition Burning System is having in improving the condition of the rangelands on the Reserve. Wild Ungulate Population The final indicator of the beneficial effect of the Decision Support System involved in the implementation of the Range Condition Burning System on Mun-Ya-Wana is the increase in the population of wild ungulates dependent on the condition and nutritional quality of the rangelands on the Reserve. An annual aerial census of the wild ungulate population of grazing and browsing animals has been conducted since 2001. The data from 2004 to 2010 constitutes the natural biological increase in ungulate numbers through reproduction. However, because range condition data are only currently available for the grass sward the population of wild ungulates will be limited to concentrate and bulk grazers and mixed feeders comprising impala and nyala, whose diet includes a significant proportion of grass. The results are presented in Figure 8. Insert Fig 8 Figure 8: The Wild Ungulate Population of grazing animals estimated for the Mun-Ya-Wana Private Game Reserve for the period 2004 to 2010. Data presented as Animal Units based on the metabolic mass of the different ungulate species. The results in Figure 8 indicate a dramatic increase of 114 % in the wild ungulate population of grazing animals on Mun-Ya-Wana during the period 2004 to 2010. This increase in the wild ungulate population of grazing animals provides significant credibility to the improvement in the condition of the rangelands on the Reserve that have been presented in Figures 5, 6 and 7 viz. increases in the forage potential, frequency of palatable, productive and nutritious Decreaser grass species and the basal cover of the grass sward. The stocking rate of -1 -1 grazing wild ungulates has increased from 27.6 ha AU to 9.2 ha AU for this period which based on practical field experience are credible stocking rates for rangelands that are in the condition of the grass sward on Mu-YaWana and which receive a mean annual rainfall of 776 mm p.a. 6. Discussion and Conclusions The set of ecological data presented for the Mun-Ya-Wana Game Reserve clearly demonstrate the value and efficacy of basing a prescribed burning program on the assessment of range condition and the use of ecological criteria for identifying areas of rangeland to be considered for burning. Ecologically informed management decisions using the Decision Support System has resulted in the increase of palatable Decreaser grass species in many areas of the Reserve. Also a reduction in less palatable Increaser grass species resulting from selective grazing where significant areas of unburnt rangeland became moribund and unavailable to grazing animals. The Decision Support System has resulted in the recovery of areas previously used for crops like pineapples, sisal and cotton, that were dominated by pioneer Increaser II grass species. This has contributed significantly to the overall increase in the potential of the rangelands to support a greater population of wild ungulate species dependent on the vegetation for their forage requirements. While on this occasion the focus of the paper has been on the herbaceous grass component of the vegetation, encroaching bush species are also being increasingly controlled by the improvement in the condition of the rangelands. This has been through the potential of the grass sward to produce greater amounts of grass fuel thereby providing the ability to apply high intensity fires under the appropriate weather conditions to reduce the size and structure of the trees and shrubs. The coppice regrowth is then browsed intensively by impala and nyala further contributing to their control. The Reserve has also demonstrated how with judicious fire management ecosystem the functioning of previously degraded areas can be re-established and transformed resulting in their return to natural savannas and unique areas like the sand forest plant communities. 8 10. References Acocks, J.P.H, 1988. Veld types of South Africa, edn 3. Mem. Bot. Surv. S. Afr. No 57: 1-146. Bransby, D.I. & Tainton, N.M. 1977. The disc pasture meter: possible applications in grazing management. Proc. Grassl. Soc. Sth. Afr. 12 : 115-118. Meikel S., Heine J., Heine L. & Trollope W.S.W., 2008. Fire Danger Rating System for prescribed burning. Working On Fire International Report: 1- 6. Mucina, L. & Rutherford, M.C. (eds) 2006. The vegetation of South Africa, Lesotho and Swaziland. Strelitzia 19. South African National Biodiversity Institute, Pretoria: 1-807. Meikel, S., Heine, J., Heine, L. & Trollope, W.S.W., 2008. Fire Danger Rating System For Prescribed Burning. Working On Fire International, Nelspruit: 1-6. Trollope, W S W and Potgieter, A L F., 1986. Estimating grass fuel loads with a disc pasture meter in the Kruger National Park. J. Grassld. Soc. Sth Afr. 3, 4: 148-152 Trollope, W S W., 1971. Fire as a method of eradicating macchia vegetation in the Amatola Mountains of South Africa - Experiment and field scale results. Proc. Annual Tall Timbers Fire Ecology Conference. 10: 99-120 Trollope, W.S.W., 1983. Control of bush encroachment with fire in the arid savannas of southeastern Africa. PhD thesis, University Natal, Pietermaritzburg. Trollope, W S W., 1989. Veld burning as a management practice in livestock production. In: Veld Management in the Eastern Cape. (eds) J E Danckwerts & W R Teague. Govt. Printer, Pretoria. Trollope, W S W., 1990. Development of a technique for assessing veld condition in the Kruger National Park. J. Grassld. Soc. South. Afr.7, 1:46-51. Trollope, W.S.W., 1999. The use of fire as a management tool. In: Tainton, N.M. (ed). Veld management in South Africa. University Natal Press, Pietermaritzburg, South Africa: 240-242. Trollope, W.S.W., Biggs, H., Potgieter, A.L.F. & Zambatis, N., 1995. A structured versus a wilderness approach to burning in the Kruger National Park in South Africa. In: West N.E. (ed.). Rangelands in a sustainable biosphere. Denver: Society for Range Management: 574-575. Trollope, W.S.W. & Trollope, L.A., 1999. Report on the assessment of range condition and the fire ecology of the savanna vegetation on the Lewa Wildlife Conservancy in Kenya – 1998. Final Report. Department Livestock & Pasture Science, Faculty of Agriculture, University Fort Hare, Alice: 1-54.