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An analysis of selected influencing factors of wildfire regimes over the last three decades in the Boland Mountain Complex, South Africa
Author(s)
Van Heerden, Andrie-Maryna
Date Issued
2024
Type
Thesis
Publisher
Cape Peninsula University of Technology
Abstract
This study examined the factors influencing wildfire regimes in the Boland Mountain Complex
(BMC), Western Cape Province, South Africa, for over thirty years. The fynbos region, covering
the BMC, is one of the world's six floral kingdoms with high levels of endemism and is both
fire-adapted and fire-dependent. Inappropriate fire regimes are a considerable concern for
biodiversity loss, and as such, it is crucial to understand the influencing factors to facilitate
decision-making. This study aims to identify and analyse the key anthropogenic, environmental
and climatic factors contributing to wildfire frequency, size, seasonality and fire return intervals
over time. A mixed-methods approach was employed to evaluate various relationships by
utilising a comprehensive dataset comprising fire records, including global position information,
satellite imagery, land use data, and meteorological records. The results showed an increase
in fire frequency and cumulative yearly hectares burnt. The cumulative hectares have a very
highly significant statistical link to the number of Very Large and Large category fires.
Therefore, in order to reduce fire size, the importance of the speed and scale of the
suppression response must be highlighted. Increased fuel load caused by the spread of
invasive alien plants (IAPs) and changes in land use as well as climatic changes mainly an
increase in temperate and drought conditions facilitate more intense fire behaviour.
Additionally, urban expansion have intensified the risk of fire ignitions but could also lead to an
increase in reporting biasness. From a space-time composite perspective, the fire return period
had an average fire return interval of 8.63 years, which is currently not conducive to maximising
biodiversity. The proximity of ignitions was examined near the closest towns and transport
routes, with Grabouw and track footpaths having the highest frequency. The hectares burnt for
each Very Large category fire has a very highly significant statistical link to biomass and total
hectares burnt in the BMC. None of the weather-related variables showed any notable links
between the dependent variable of total hectares burnt per Very Large fire category. This could
be due to distance from weather stations and variations in microclimates within mountainous
areas. There is, however, a notable link between antecedent annual rainfall and the fire
frequency and cumulative hectares burnt in the BMC for the same year. This research shows
an overall trend of increased fires, highlighting key risks and specific geographical areas as
hotspots. It is recommended that results from long-term monitoring, research, and input from
all stakeholders must be regularly assessed and reported back into legislation, prediction,
prevention, preparedness, suppression, rehabilitation recommendations, and planning.
Integrated wildfire management should also be viewed holistically, considering all
stakeholders' needs and capacity, coordinating all stakeholders' management efforts, and
continually practising adaptive management.
(BMC), Western Cape Province, South Africa, for over thirty years. The fynbos region, covering
the BMC, is one of the world's six floral kingdoms with high levels of endemism and is both
fire-adapted and fire-dependent. Inappropriate fire regimes are a considerable concern for
biodiversity loss, and as such, it is crucial to understand the influencing factors to facilitate
decision-making. This study aims to identify and analyse the key anthropogenic, environmental
and climatic factors contributing to wildfire frequency, size, seasonality and fire return intervals
over time. A mixed-methods approach was employed to evaluate various relationships by
utilising a comprehensive dataset comprising fire records, including global position information,
satellite imagery, land use data, and meteorological records. The results showed an increase
in fire frequency and cumulative yearly hectares burnt. The cumulative hectares have a very
highly significant statistical link to the number of Very Large and Large category fires.
Therefore, in order to reduce fire size, the importance of the speed and scale of the
suppression response must be highlighted. Increased fuel load caused by the spread of
invasive alien plants (IAPs) and changes in land use as well as climatic changes mainly an
increase in temperate and drought conditions facilitate more intense fire behaviour.
Additionally, urban expansion have intensified the risk of fire ignitions but could also lead to an
increase in reporting biasness. From a space-time composite perspective, the fire return period
had an average fire return interval of 8.63 years, which is currently not conducive to maximising
biodiversity. The proximity of ignitions was examined near the closest towns and transport
routes, with Grabouw and track footpaths having the highest frequency. The hectares burnt for
each Very Large category fire has a very highly significant statistical link to biomass and total
hectares burnt in the BMC. None of the weather-related variables showed any notable links
between the dependent variable of total hectares burnt per Very Large fire category. This could
be due to distance from weather stations and variations in microclimates within mountainous
areas. There is, however, a notable link between antecedent annual rainfall and the fire
frequency and cumulative hectares burnt in the BMC for the same year. This research shows
an overall trend of increased fires, highlighting key risks and specific geographical areas as
hotspots. It is recommended that results from long-term monitoring, research, and input from
all stakeholders must be regularly assessed and reported back into legislation, prediction,
prevention, preparedness, suppression, rehabilitation recommendations, and planning.
Integrated wildfire management should also be viewed holistically, considering all
stakeholders' needs and capacity, coordinating all stakeholders' management efforts, and
continually practising adaptive management.
Additional information
Thesis (Master of Environmental Management)--Cape Peninsula University of Technology, 2024
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