Images from outer space have revealed the astonishing rate of human transformation of the natural landscape in KwaZulu-Natal over the past 20 years.
A new study in the latest edition of the SA Journal of Science also suggests that nearly 8% of KZN’s undisturbed natural space disappeared in six years – to be replaced by new farms, timber plantations, dams, mines or expanding human settlements.
The study, by researchers from Ezemvelo KZN Wildlife, Wits University and the SA Environmental Observation Network, was based on an analysis of satellite images and land-cover transformation maps.
By comparing satellite photos between 2005 and 2011, they found that 7.6% of the natural habitat in KZN was lost to human transformation.
The imagery showed that 73% of KZN was still in a natural state in 1994.
By 2011, only 53% remained in a natural state, and if this trend continued it was likely that only 45% of the landscape would be left in a natural state by 2050.
“The province is experiencing a loss of natural habitat which has profound consequences for this species-rich area,” said lead author Debbie Jewitt and colleagues Peter Goodman, Barend Erasmus, Timothy O’Connor and Ed Witkowski.
They said there were more than 10.8 million people in KZN (roughly one person a hectare).
Since 1994, an average of 1.2% of the natural landscape had been transformed by human activity each year.
New farming land accounted for the lion’s share. Of the nearly 722 000ha of natural vegetation lost since 2005, expansion of agriculture accounted for about 496 000ha of the transformed land.
The built environment expanded by more than 111 000ha, while commercial timber plantations took over nearly 46 000ha of untransformed land. New dams, mines and soil erosion had also played a significant role in land transformation.
In 2005, there were about 14 450 dams in KZN. Six years later, there were nearly 21 000 mainly small dams. Over the same period, the area covered by mines increased by 90%, while eroded areas increased by 44%.
Jewitt, an ecosystem ecologist at Ezemvelo KZN Wildlife, said the dramatic loss of habitat raised the question of whether this level of habitat loss was sustainable.
“In light of calls for further development, a major rethink is required in order to determine how this development should be implemented,” she said.
Once natural habitat was reduced below 50% there was likely to be a rapid decline in the ability of natural areas to support viable populations of animals, plants and other natural organisms.