Creative fire management can increase habitat for grazing animals in national parks
A recent paper by scientists from Wits University in South Africa shows how creative fire management can increase habitat for wildebeest and other grazing animals in national parks.
The work, published in the Journal of Applied Ecology shows that small, repeated fires can have a concentrating effect on animals, and create ’grazing-lawn ecosystems’ where food quality is higher and herbivores can see predators from further away.
Navashni Govender from the South African National Parks (SANParks) joined up with prof Sally Archibald from Wits University and prof Catherine Parr from the University of Liverpool. Together with a team of graduate students and technicians, and with the support of Working on Fire, Govender, Archibald and Parr set up a large-scale experiment near Satara Restcamp in the Kruger Park in 2013.
Over the following three years fires of varying sizes were lit annually in the early- and late-dry season of each year and the type and number of grazers visiting burns was monitored by looking for the presence of dung on burn sites. The response of grass to the grazing herds was also measured with plots that were never burnt, used to compare any changes.
“After 5 years the results are conclusive,” says Archibald. “Our PhD student, Jason Donaldson, has shown that all grazers increase their use of small burns (<25ha) after a fire and that the number of animals on these smaller burns is large enough to keep the grass short and palatable for longer periods.”
Wildebeest remained on these small burns and actively selected them over areas where burns were absent, and grass was taller. The continued high number of wildebeest on small burn patches ultimately kept grass very short (<5 cm) over large areas of the plots and made it impossible for plots to be burnt again. This is in contrast to the large, landscape fires that generally occur in this system, which only create good habitat for wildebeest for a few weeks after the fire.
The collaborators are now investigating whether smaller animals, like grasshoppers, benefit from the management intervention, and have found three families that were unique to short-grazed patches, increasing biodiversity overall.
“The research adds to a growing understanding of the interactions between fire, grazers and grass structure and function in savannas, and highlights the importance of understanding feedback between fire management policies and wild herbivores,” says Donaldson. “The collaborators have been testing this management tool in other ecosystems in Africa, and are also, with collaborators from the University of Pretoria, exploring what this means for rangeland systems where cattle, not wildebeest are the dominant grazers.”
Fire management may seem like a contradictory idea to some, who view it as a destructive force of nature, but humans have been making use of the effect of fire on vegetation structure and animal movement since before the rise of modern man.
Modern-day land managers still rely heavily on fire to manage grasslands in Africa with commercial farmers and migratory pastoralists both burning savannas to provide fresh growth for livestock and to keep areas clear of thick brush.
The Kruger National Park is exploring the possibility of using this new insight to manage the southern Basalt plains, which are notoriously low in animals despite their high soil fertility.