Professor Stefan Siebert.
Two researchers from the North-West University (NWU) participated in the compilation of the largest international database of its kind to determine the impact of urbanisation on biodiversity across the world.
The data of plants in 110 cities and birds in 54 cities were studied by a team of 24 researchers from 10 countries. Professors Sarel Cilliers and Stefan Siebert from the subject group Botany at the NWU are the only South Africans who participated in the study. They made available data collected during many years of research in Potchefstroom and Ganyesa (North West).
The study showed that 20% of the world’s bird species — and 5% of plants are found in cities. This finding appeared earlier this year in the international journal, Proceedings of the Royal Society B. This article has recently been identified as the “most viewed paper in science” by Nature, one of the most authoritative journals in the natural sciences.
Cilliers says the study has determined that urbanisation drastically reduces the number of indigenous species, which was to be expected. “It is encouraging that there are still many indigenous species that are typical of the natural environment in which the cities were developed — despite the impact and change of urbanisation.”
Only one bird species, the rock dove (Columba livia), and among the plants, an annual meadow grass (Poa annua), occurred in all the studied cities. He says their research is not merely about studying biodiversity, but also about the meaningful planning, conservation and management thereof. “Every city should have a well-structured biodiversity conservation plan in place. We have to conserve urban biodiversity, not only to protect our natural and cultural heritage, but also because it affects human health and wellness.
“People often ask why biodiversity needs to be conserved, what do we get from it?” says Cilliers. The answer can be found in the services delivered by ecosystems and biodiversity. Ecosystem services can be categorised in four main types: provisioning services (for instance plants provide food and medicine), regulating services (for instance wetlands purify water, regulation of climate and absorption of contaminants by plants), habitat services (pollination of plants by insects), and cultural services (parks for aesthetics and recreation). Urban ecological researchers of the NWU have been studying the biodiversity of several urban regions and settlements in the North West since 1996.
Fifty-three scholarly articles, chapters in books and dissertations about the urban ecology of the province have been published to date (even more than in Gauteng and KwaZulu-Natal). These databases were also used for the international study. Very few urban areas can boast the database of biodiversity of all land-use areas, from pavements to fragmented natural areas that Potchefstroom has.
“They knew about our research, which is why we were invited to the workshop in the US and to write this and other articles.” According to Cilliers, the study has also led to two subsequent projects funded for five years and three years respectively by the National Science Foundation in the US and the National Socio-Environmental Synthesis Centre at the University of Maryland in the US. During this period extended workshops will be held in several countries, including South Africa.
These projects will study cities as complex socio-ecological systems. Researchers from the University of Cape Town and the municipality of Durban will also participate in these studies. Cilliers is currently on sabbatical at the Stockholm Resilience Centre in Sweden, which is internationally known for their research into socio-ecological systems.
This supplement has been paid for by the North-West University Potchefstroom Campus. Contents and pictures were supplied and signed of by the NWU