A fire management environmental decision support system for the uKhahlamba Drakensberg Park World Heritage Site.

Abstract

Fire is a major disturbance force that affects global ecosystems and associated biomes and plays a pivotal role in the determination of ecosystem structure, functionality and dynamics. Anthropogenic environmental disturbances have resulted in shifts in fire regimes and the biogeochemical processes of these ecosystems are thus unable to function as they have done in the past, impacting both floral and faunal species. Therefore there is a need for anthropogenic management. Prescribed burning is one of the few beneficial fire management options available to decrease the severity of wildfires, decrease the associated costs in suppressing these fires and restore fire-dominated ecosystems. The uKhahlamba Drakensberg Park World Heritage Site (UDP-WHS) is predominantly managed for water resource and nature conservation, and fire hazard reduction. It is divided into management compartments in which prescribed management burns are conducted, (i.e. manager’s burn by compartment). These compartments are subdivided by three altitudinal belts (alpine, sub-alpine and montane). Each of these belts contains different vegetation communities and therefore requires different fire regimes. However these compartments do not coincide with the natural contours and consequently, the altitudinal belts of the Park. This is problematic for management as a certain percentage per altitudinal belt is required to be burnt annually. When burning a compartment that falls within two or more belts, the total area of that compartment needs to be sub-divided into its respective altitudinal belts as a whole compartment can be prescribed to burn not a sub-division thereof. A fire management environmental decision support system (EDSS) was developed to achieve prescribed burning objectives in the UDP-WHS. The system is based on ecologically ideal fire regimes and fire management objectives of the heritage site, using GIS and associated graphs to visually display the required fire regimes. The EDSS data preparation, statistical analysis and modelling was completed using ESRI ArcGIS suite (ArcMap, Scene and Catalog). Its main components are two models, an excel spreadsheet and an ArcMap document. The spreadsheet contains the historical burning data of the management compartments based on the compartment codes, with each compartment being not burnt or having a burning treatment. Years Since Last Burnt (YSLB) was calculated from these data and joined to the management compartments in the ArcMap document. The Intermediate output model was developed to create numerous temporary outputs allowing decision makers to decide which compartments to treat with prescribed burning by re-running the model with required alterations. The second model (Final Output model) is then run to export the selected burning treatment in table format to update the original historical data, and consequently YSLB, in the excel and ArcMap document. The ArcMap document contains the user interface housing the graphs for each altitudinal belt showing the percentage area selected to be burnt per YSLB compared to the minimal, maximum and ideal fire regimes. The fire management EDSS for the UDP-WHS consists of an ArcMap document, geodatabase, excel document and folders, which are all housed in one single folder. The use of GIS and EDSSs in environmental management improves the efficiency and accuracy of the decision making process and provides the ability to validate outputs.