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A scientific heritage neglected?
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Any society would normally cherish its cultural heritage, important hallmarks of which are commonly preserved for enjoyment by the public in museums and galleries. I wish to propose that our legacy of scientific endeavour relating to the natural world is deserving of similar protection for future use by our scientific community.
I write about long-term field experiments conducted by natural resource agencies and universities. Although this article reflects personal opinions, it was motivated by the potential benefits recognised for SAEON in maintaining these experiments for purposes other than those for which they were established.
The workings of the natural world are not easily understood. A scientist embarking upon their first major study is soon confronted by bewildering complexity.
I attempted to understand the effects of grazing on rangeland dynamics but soon had to confront simultaneous and complex synergistic effects of fire type, season of burning, animal type, animal numbers and distribution, season of grazing, rainfall variability, tree abundance, and soil type, to name a few. Insights gained were obviously incomplete, but hopefully a piece was added to the puzzle. My experiences cemented the viewpoint that a deeper understanding could only emerge if an appropriate period of ecological time was studied – decades, not years.
How might we increase the rate and quality of pieces added to a puzzle? A foundation stone of the scientific approach is to tease apart experimentally the effects of individual factors. This approach is as relevant now as it was between 1930 and 1960 when a host of field experiments were set up across the country. The most prominent of these during this golden era were the trials conducted by agriculture, water affairs and forestry, national parks, other conservation agencies, and associated universities. These entities did not undermine the potential quality of their science by constraining it to a short-term funding cycle -- they were in it for the long run.
The experiments addressed objectives relevant to their time. A common critique is that the original objectives are no longer relevant and that the money could be better used for other research. I posit an alternative that they offer high quality, cost-effective opportunities for emerging theoretical and applied issues. A range of cases is described in order to demonstrate their broad value.
Climate change observatories
The former Department of Water Affairs and Forestry established experimental catchments throughout the country during the 1950’s in order to determine the effect of various land uses or management practices on water yield. Jonkershoek outside Stellenbosch is one of the oldest catchment experiments in the world. Their design and scale (15 catchments at Cathedral Peak) is a magnificent testament to the vision of these early workers. Current policy regarding forestry permits and burning regulations were founded on these efforts. Society’s investment has been repaid many times over.
Climate change poses a new threat to water security. Almost fortuitously, these experimental catchments are ideally located and already have an appropriate long record for detecting climate-induced changes in flow. If we had to start anew, it would be decades before changes in water yield could be distinguished from year-by-year variability. ‘Cheap at the price’, whatever they might cost to maintain.
Many might argue that most grazing and fire experiments are past their sell-by date because grazing and fire practices have been modified considerably since initiation of these trials. However, the effect of an external agent, such as climate or CO2, on vegetation might best be detected by witnessing a similar direction of change across dissimilar treatments.
SAEON and the Department of Agriculture have identified a possible climate-induced shift from karoo to grassland vegetation, based on 70 years of recorded vegetation change of grazing trials (Camp 6, Bergkamp) at Grootfontein in the Northern Cape. Seasonal grazing systems have resulted in stark differences in woody vegetation -- the Karoo may yet provide some insights on a topic of perennial interest to savanna ecologists.
Other grazing trials suggest that medium-height grassland may be giving way to tall Hyparrhenia grassland on the Mpumalanga highveld. Furthermore, grazing and fire practices will undoubtedly have to be adapted to climate change -- these experiments will continue to have agricultural relevance as well.
In effect, we have inherited a set of observatories for climate change which are well distributed across the country, provided they can be maintained.
Experimental legacy
Biodiversity conservation has emerged as an issue of global concern. Initiatives to ‘mainstream’ biodiversity conservation into the production sector are faced with a relative dearth of knowledge about the effects of management practices on biodiversity. Most of our research on biodiversity has been concentrated in protected areas. Long-term fire and grazing experiments have offered a ‘quick-fix’ approach for providing initial statements for grassland, karoo, and savanna.
Nitrogen loading is of concern throughout the industrialised world. What might happen to ecosystems subjected to prolonged loading of this element? Some answers have been provided by an elegant fertilizer experiment (initially for hay production) that was established on the Ukulinga Research Farm of the University of KwaZulu-Natal in the 1950’s.
The above example illustrates that our experimental legacy has plenty to offer theoretical ecology -- concepts relating to nutrient availability are at the core of current ecological theory. Burning experiments have contributed to gaining an understanding of the importance of fire as an ecological and evolutionary agent of our ecosystems. Detailed study of vegetation succession in response to fire preclusion has been achieved. The similar potential of grazing experiments for theoretical ecology has yet to be pursued.
This legacy is slipping away. Some agricultural research stations have been completely lost. nThabamhlope research station in KwaZulu-Natal has supported long-term grazing, fire and catchment trials since its founding in the 1930’s. These trials ceased when the station was handed over to the local community in the mid-1990’s.
The Estcourt research station experienced a similar fate. Coal mining has commenced on Nooitgedacht research station. Organisational changes precipitated the collapse of 60 years of catchment experiments at Cathedral Peak in the Drakensberg. Fire and grazing experiments have collapsed at Athole, Dohne and Nooitgedacht, amongst others. Most long-term exclosures have been dismantled in the KwaZulu-Natal parks. Fortunately, Kruger National Park was dissuaded from abandoning its long-term fire experiments.
It is not yet too late to halt and reverse this trend. Despite the above-mentioned losses, a robust ensemble of long-term experiments still remains for future scientific endeavour. Some of those lost, such as catchment monitoring, could still be revived.
Partnerships among government departments, SAEON, and academic institutions might offer a means forward for securing this heritage. Their value might be better appreciated when production landscapes are accorded the same interest as protected areas by researchers.
Related content:
- SAEON extends period of financial support to Jonkershoek
- Long-term hydrological monitoring at Jonkershoek aids climate change studies
- SAEON safeguards 80 years of long-term observation records
- Recognising voluntary contributions to long-term monitoring
