Kruger Park Fire Raises a Storm

Park visitors came across severely burnt animals, notably rhino, and conveyed their horror to the media. The article sparked a flood of similar complaints from other visitors, as reported in a follow-up article on Independent Online.

"After the publication of the story, more visitors to the park said they had encountered several burnt and dead elephants - including a calf - impala and critically endangered ground hornbills in the past two weeks. "A visitor, who did not want be named for fear of being victimised, said he had seen numerous badly burnt animals last week.

"We were on the dirt road next to Afsaal on our way to Lower Sabie when we saw one elephant and dead birds - hornbills next to the road. There were also small antelope like duikers. One side of the elephant looked like acid had been thrown on to it." Another park visitor, Russell Bruton, lamented the lack of accountability evidenced in the "cavalier" responses from officials quoted in last week's story. This implied officials were happy to repeat the "disastrous experiment", he said.

"They proffer that animals must get out the way because fire is natural, totally ignoring the fact this fire was intentionally set to be so intense only flighted birds could escape.

"What of breeding herds of elephant with calves, of which the cow in these pictures was probably a part; where is her calf; where are the others? Or rhino, or buffalo, or anything else with young?" Park visitor Teresa Agenbag said her sister had come across a burnt rhino last week being hounded by wild dogs and hyenas. "It was distressed and wouldn't let cars pass." (Independent Online, October 16).

The response from the Kruger National Park

Fire is a natural and important component of savannas, such as the KNP, and both plants and animals have adapted to fire through the millennia. Ignition sources for fire in Kruger are many and varied. Nevertheless, fires are usually started by man (tourists, poachers, trans-migrants, fires crossing from the outside the park's borders) under warm environmental conditions (high temperatures and low relative humidity) and this often leaves rangers fighting large runaway fires. The current fire policy in the Kruger Park aims to reduce the number of large and hot runaway fires in the August - September late dry season by setting smaller and cooler management fires in May - June to break up the fuel load in the veld with burnt and un-burnt patches.

Kruger's vast area, spanning nearly two million hectares of the Lowveld, constitutes a diverse and highly variable ecosystem. Persistence of this variability is a key to the great tourism product that the national park offers. This also requires variability in the nature and extent of fires that burn across these vast landscapes. Nevertheless, over time, a steady decrease in very large trees has been observed in most landscapes in the KNP, with a concurrent densification of the shrub layer in the western granitic areas of the Park. Tall trees play an important role in the ecosystem as nesting sites for large birds, as moisture and mineral pumps from deeper soil layers to the upper layers and also as shade for animals and tourists alike.

It is understood that elephants and fire are playing interactive and contributing roles in these processes. Some renowned scientists, such as Prof William Bond from the University of Cape Town, also attribute the bush densification phenomenon to an increase in atmospheric CO2 levels. Such a change in woody vegetation structure on a large scale will impact negatively on plant and animal species that prefer more open areas, and also on the associated game viewing experience for tourists.

A very dense shrub layer will make certain antelope species more vulnerable to predation while certain predators prefer more open areas for hunting. Rare and threatened species such as roan antelope, tsessebe, cheetah and wild dog prefer more open areas and have declined over the past decades. Current atmospheric CO2 levels are the highest they have ever been in the last million years.

This favours woody plants above savanna grasses more than ever before in the history of savannas. Higher CO2 makes woody plants grow faster, sprout better after fire and build defences (spines, tannins) more easily. This competitive advantage of woody vegetation has resulted in significant and increased encroachment of woody vegetation into our grasslands over the past few decades. In addition, substantial alteration and thickening of savannas translates into a potential loss of a crucial biome which currently sustains millions of people and their livelihoods in Africa. Bush thickening appears to be taking place in most South African savanna areas as well as in certain other areas in the country.

Fire is a natural process, but also an important tool that managers can use to combat bush thickening. Animals such as white rhino, zebra, wildebeest, roan antelope, tsessebe, cheetah and wild dog prefer open savannas and will benefit from more open areas created by judicious use of fire by park managers. In such a large, natural area such as the Kruger Park, it is clearly impractical to use herbicide or mechanical means to combat bush thickening.

The experiment

In southern KNP in particular, for example east of Pretoriuskop and south of the Biyamiti River, it is obvious how woody shrubs, especially Combretum and Terminalia are increasing in density in what used to be much more open areas. This area was therefore selected to rigorously and scientifically test the use of fire as an appropriate tool to learn more about the role of fire in shrub densification and the loss of tall trees. An experiment was thus designed as part of an active adaptive management process to implement very hot fires, so called "firestorms", in two blocks in the Kruger Park.

Blocks that showed significant bush thickening and densification of the shrub layer were identified in the Malelane and Pretoriuskop sections in conjunction with section rangers. The experiment was approved by the Kruger Park Conservation Committee and the KNP Fire Protection Association (FPA) and a permit with conditions for the experiment was obtained.

The experiment and its conditions were also discussed with Working on Fire, the Lowveld and Escarpment FPA as well as with the Department of Agriculture, Forestry and Fisheries (DAFF) Veldfires Oversight Directorate and all parties indicted that they were satisfied with the conditions and safety procedures for the experiment. The mandate given to SANParks via periodic public meetings followed by approvals by the SANParks EXCO, the SANParks Board and DEA on the management plan has several objectives which support all of the above thinking in concept and often in particular detail.

Baseline data were collected to assess the impact of "firestorms" on woody vegetation. The Carnegie Airborne Observatory (CAO) assisted with flying the experimental areas to obtain high resolution LiDAR images of the three dimensional structure of vegetation before the fires were put in. CAO plans to return to the same area with a follow-up aerial campaign in 2011 to assess and quantify the change in vegetation structure caused by the firestorm experiment. Detailed field information was also collected pre and post the fire experiment on tree and shrub height and density and bark damage for different woody species to quantify fire impact.

Working on Fire

The Working on Fire team based in Nelspruit were actively involved in the planning of the experiment and assisted with burning the firebreaks as well as setting and controlling the experimental fire on 15 September using the latest aerial ignition technology. Before the blocks were set alight a helicopter was used to chase rhino and elephant out of the blocks. The fire front was first set alight on the western side along the tar road with a westerly wind.

The northern, eastern and southern flanks of the experimental blocks were left open to allow game to move out ahead of the fire front. In both blocks there were also a number of sodic sites without grass, areas that could act as refuge areas for game to move onto to get away from the fire. The blocks were burned as planned with no damage to any people or infrastructure. Rangers flew over and patrolled the blocks frequently the days after the fire, to look for injured game which may have needed to be euthanized.

Unfortunately in the days just after the experimental fires, which burnt about 12 000 hectares, an arsonist walked through the southern Kruger Park and set numerous fires under extreme environmental conditions. This and other arson fires this year have burnt 67 000 hectares in southern KNP. Nevertheless, in spite of precautions taken such as extensive firebreaks created for animals to move into, some animals were burnt in the experimental fire in spite of all precautions taken and a number of animals were also burned in the arson fires. Rangers continued to look for burnt animals and when found they would evaluate their condition. Some were put down immediately and others were monitored to see if they could recover.

The value system necessarily associated with managing large natural areas obviously includes condoning the many (normally cruel or violent) ways in which animals naturally die in such systems, though we as human custodians feel obliged to, whenever feasible, euthanize injured animals (especially) if human interference caused this. Generally we strive to limit such human interference in our management, but some is needed and it is always a sad event when such an animal has to be euthanized.

Due to the changing climate that we are managing within, with high air temperatures, lower relative humidity and increasing fire danger indices, fires that burn under the conditions that the experiment was lit under are becoming more frequent. However, in order to learn from, to use, adapt and manage these fires in the future we have to study how a high intensity fires burns and how the vegetation responds.

Pre-fire, post fire and re-growth vegetation surveys, pre and post fire LIDAR data and satellite images have been taken in order for us to study and learn from the experiment.

These data are essential to assist us to better predict, control and manage for firestorms (induced or natural) in the future and will help to set realistic monitoring thresholds for bush encroachment and/or disappearance of tall trees, and for fire, so that park management can be informed with the best possible understanding in a difficult and changing world.

Kruger National Park - South African Safari