Strydom (2025) Climate-related drivers of fire danger and activity in the Drakensberg mountains, South Africa

Identification

• Journal: Theoretical and Applied Climatology
• Year: 2025
• Date: 2025-10-17
• Authors: Sheldon Strydom
• DOI: 10.1007/s00704-025-05811-6

Research Groups

• Department of Geography, Rhodes University, Makhanda (Grahamstown), South Africa

Short Summary

This study quantifies the geospatial characteristics and trends of fire activity and danger in the uKhahlamba-Drakensberg Park (UDP), South Africa, linking observed changes to climate variability. It found significant increases in fire activity and fire danger in specific areas of the park, driven by changes in atmospheric conditions such as temperature, relative humidity, and wind speed.

Objective

• To quantify trends and variability in fire danger and activity in the Drakensberg mountains.
• To assess the role of climate change in altering the fire climatology and pyrogeography of the uKhahlamba-Drakensberg Park (UDP) region.

Study Configuration

• Spatial Scale: uKhahlamba-Drakensberg Park (UDP), South Africa, a World Heritage Site. Three specific ground-based weather station sites: Royal Natal National Park (1420 m elevation), Giant’s Castle (1740 m elevation), and Shaleburn (1600 m elevation).
• Temporal Scale:
  • Satellite fire activity data: 2001–2021 (21 years).
  • Ground-based meteorological data: 1990–2021 (site-specific durations, ranging from 27 to 31 years).

Methodology and Data

• Models used:
  • Lowveld Fire Danger Index (LFDI) for fire danger quantification.
  • Optimised Hotspot Analysis (Getis Ord Gi statistic) for identifying significant spatial clusters of fire activity.
  • Kernel Density Analysis for identifying areas of high fire frequency.
  • Sen’s Slope estimator for determining rates of change in time series.
  • Mann-Kendall method for testing the statistical significance of trends.
  • Coefficient of Variation (CV) for quantifying interannual variability.
• Data sources:
  • Satellite: NASA Earth Observing System Data and Information System (EOSDIS) Moderate Resolution Imaging Spectrometer (MODIS) Active Fire Product (1 km spatial resolution) and MODIS Burned Area Product (500 m spatial resolution).
  • Observation: South African Weather Service (SAWS) long-term daily meteorological records (maximum and minimum air temperature in degrees Celsius, maximum and minimum relative humidity in percent, wind speed in meters per second, and daily total rainfall in millimeters).

Main Results

• Overall fire activity in the UDP increased by approximately 30 fires per decade between 2001 and 2022, though this trend was not statistically significant.
• The winter fire season (June, July, August - JJA) experienced a significant increase of approximately 51 fires per decade and a significant increase in burned area of approximately 10,300 hectares per decade.
• The autumn season (March, April, May - MAM) showed a significant decrease of approximately 9 fires per decade and a significant decrease in burned area of approximately 3574.40 hectares per decade.
• Geospatial analysis revealed significant increases in fire activity in the Central UDP (Cathedral Peak, Cathkin Valley/Giant’s Castle areas) and significant decreases in the Southern UDP. The Northern UDP (Royal Natal Park) showed no significant change.
• Lowveld Fire Danger Index (LFDI) increased significantly at Royal Natal Park (1.81 units per decade annually, 1.86 units per decade in JJA), driven by significant decreases in relative humidity (-30.50% per decade) and increases in wind speed (0.23 m/s per decade).
• Giant’s Castle experienced a significant annual air temperature increase (0.37 °C per decade) and a significant relative humidity decrease (-36.20% per decade), with seasonal LFDI increases being significant in MAM, SON, and JJA (at 90% confidence).
• Shaleburn showed a significant annual air temperature increase (0.84 °C per decade) and a significant relative humidity decrease (-1.41% per decade), but no significant annual LFDI change.

Contributions

• Provides a spatially explicit quantification of fire activity and fire danger trends in the uKhahlamba-Drakensberg Park, a globally important World Heritage Site, addressing a gap in mountain fire climatology research.
• Establishes a clear link between observed changes in local climate variables (air temperature, relative humidity, wind speed) and increasing fire danger and activity in specific mountain regions.
• Offers critical insights for fire management strategies in sensitive mountain environments, highlighting areas of increasing risk and the need to adapt to a warmer, drier, and windier climate.

Funding

• National Research Foundation
• Rhodes University (Rated Researcher Incentive Fund)

Citation

@article{Strydom2025Climaterelated,
  author = {Strydom, Sheldon},
  title = {Climate-related drivers of fire danger and activity in the Drakensberg mountains, South Africa},
  journal = {Theoretical and Applied Climatology},
  year = {2025},
  doi = {10.1007/s00704-025-05811-6},
  url = {https://doi.org/10.1007/s00704-025-05811-6}
}