Global change includes the effects of increased atmospheric carbon dioxide levels and the associated changes in temperature and rainfall. In the immediate future (2050) of eastern South African these predicted changes include an increase of 2-3oC and a more variable rainfall regime with more intense wet periods interrupted by prolonged periods of drought. These changes are likely to impact ecosystems at higher altitude first, such as those on the slopes of the northern escarpment in Limpopo. The interaction between climate and fire frequency currently determines the distribution of the grassland, savanna and forest biomes in the region. Global change has the potential to alter the composition and distribution of these vegetation types. A common prediction is for the encroachment of savanna and forest tree species into the threatened remains of open grasslands. However, no on-the-ground research has been carried out to test this prediction and this limits our ability to plan for their protection in the future.
The Phalaborwa-based Ndlovu node of the South African Environmental Observation Network (SAEON) has initiated a long-term vegetation monitoring program to track the fate of grasslands and savannas over the next several decades. The area surrounding the small town of Haenertsburg supports vegetation of remarkably high biodiversity, and has been chosen as the primary field observatory for this research initiative. The research is based on similar long-term projects being conducted in the northern hemisphere, but has been adapted to suit the local situation, and will provide locally and globally relevant answers. The investigations will take a multi-scaled approach – from monitoring individuals and species-level responses to global change and fire through to mapping large-scale shifts of the grassland-forest and grassland-savanna boundaries.
In order to collect the necessary information, 60 4m x 4m permanent monitoring plots have been marked in the annually and triennially (3-year) burned management blocks across the Haenertsburg common. By repeatedly monitoring the vegetation within these plots into the future – and by recording the species present and the occurrence of woody shrubs and trees, we will be able to demonstrate climate–induced changes at the community-level. In addition, by intensively monitoring a further 240 1m x 1m plots we will be gathering information which will allow us to understand not just the changes in vegetation but, as importantly, how these changes come about. Understanding the process of change, together with the role of fire, will allow us to effectively manage and maintain grassy ecosystems.
Secondary monitoring sites have been set up by the Ndlovu node on the Ebenezer Dam peninsula - just outside of Haenertsburg, as well as in the Soutpansberg in northern Limpopo. Plans are also in place to join forces with the newly-established SAEON node in Pietermaritzburg to replicate this monitoring in the KwaZulu-Natal Drakensberg, and to collaborate with similar research activities being carried out on the Blyde escarpment at Mariepskop. Through these links, the Haenertsburg grassland is part of a local network of biodiversity observatories that will provide the information necessary to understand and react to the impacts of global change on montane grasslands at the national scale. An exciting new development is the interest shown by The Mountain Research Initiative – a Swiss research organization, to include SAEON Ndlovu’s monitoring sites (including the Haenertsburg grassland) as part of an international network of ecological observatories.
Another initiative from the Ndlovu node – in an effort to understand the consequences of global change on biodiversity, is the monitoring of phenology (the timing of biological events such as flowering, migration) in plants and animals locally. This monitoring is being carried – not by scientists, but by volunteer citizens and so needs your involvement! The BIRD’S EYE VIEW migration monitoring project was started in 2007 and simply asks that people be on the lookout for the first arrival of easily recognisable migrant bird species in their area, and then to catalogue the arrival dates with SAEON. The two projects launched this season focus on the timing of important and conspicuous plant life cycle events and are geared more towards the keen gardener and amateur botanist. CLIMATE BUDDY is concerned with monitoring the opening dates of flower buds in spring, while the TURNING A NEW LEAF project aims to track spring leafing and autumn leaf drop in deciduous trees. Being a SAEON citizen scientist is the ideal way for environmentally-conscious people to make a great contribution.
People wanting to know more are welcome to contact Dave – the Biodiversity Research Manager for the Ndlovu Node, on +27 (0)13 735 3534 / 35 or email@example.com.