In order to meet their mandate, the staff of scientific services has been getting out and about - getting their hands dirty, their brows sweaty, their power tools revved up and their brains in high gear to meet the challenge of conserving Kruger’s precious flora and fauna.
The Kruger National Park has the declared mission of “maintaining biodiversity in all its natural facets and fluxes”, and it has a truly impressive array of biodiversity – official figures quote 49 species of fish, 34 amphibians, 114 reptiles, 507 birds and 147 mammals. But biodiversity is an all-encompassing kind of word, so one has to include the more than 200 different kinds of grasses, about 400 different kinds of trees and shrubs and well over 1,000 other sorts of plants.
And all this doesn’t even consider the insect life underpinning the park’s ecosystem - about half of southern Africa’s known species of insects are thought to occur in Kruger, producing the slightly mind-boggling figure of some 20,000 insect species in the park. In Kruger’s burn plots alone, 169 species of ants have been found. The insect life of the park is sufficient to sustain 39 different species of insectivorous bats.
And to further boggle the mind, experiments done near Skukuza have revealed that in the knobthorn-marula woodlands of the park in the summer months there are about 2.4 tonnes of insects in the tree canopies in one square kilometre of woodland. In comparison, if all the herbivores the size of an impala and larger are considered in the same size area, they only add up to 2.3 tonnes.
Now think about the termites, grasshoppers and other insects that live lower down – the creepy crawlies start to outweigh the big and hairies by a long shot, and cannot be ignored in conservation efforts. All this biodiversity is one of Kruger’s greatest strengths and assets, but when you have tens of thousands of species to consider, how can you tell if you are effectively conserving them all, not just the elephants?
Especially when Sanparks considers that biodiversity also includes all the processes in the ecosystem - how all the ani-mals and plants live and function together. All the processes are interlinked and need to be conserved, not just the species alone. This is the challenge facing scientific services, and November was the month when ideas discussed in management meetings were put into practice.
Although not all the details are finalised, the staff of scientific services has come up with a plan to conduct biodiversity surveys throughout Kruger. Since 1989, Kruger has had a number of fixed plots where Veld Condition Assessment (VCA) is carried out every year.
For just under a decade, the surveys of the VCA plots focussed on grasses – species, composition and abundance – but in 1997 the programme was expanded to evaluate the trees and shrubs in the plots. There are currently 527 VCA plots scattered throughout Kruger, and the section rangers usually spend many hours in the VCA plots each March, performing the somewhat tedious job of measuring and recording what has sprouted from the soil.
Kruger scientists have now realised that the previous emphasis on plants is not sufficient to trace changes in biodiversity. Starting from next year, selected plots will act as sites for the added dimension of biodiversity monitoring. Much work has been done in recent years on how to best sample for different kinds of biodiversity, and Kruger’s experts consulted with experts from Sanbi (South African National Biodiversity Institute), the Organisation for Tropical Studies (OTS) and several wellknown Australian scientists before going into the veld to check out the various methods that can be applied at each selected site.
One of the main methods of finding out about the small creatures that skitter and scamper on the ground is to use pitfall traps. This is essentially a bucket buried in the ground that unsuspecting creatures tumble into and then cannot escape from due to the steep sides.
The pitfall trap is refined with the addition of three drift ‘fences’ – plastic sheeting radiating out from the central pit that channels small animals into the trap. The drift fences are too low to be a problem to larger animals, but the smaller ones follow the fences into the pit. These pits are especially effective in trapping reptiles and amphibians.
Other ways of sampling biodiversity include setting out specialised small baited traps for animals like rats, mice and mongooses and long funnel traps for snakes. Birdcalls and sightings are also recorded to estimate the bird diversity in the area. To improve the knowledge of the numbers and distribution of small antelope (like duiker and steenbok) the antelope dung heaps in the area will also be recorded. Information like the presence of termite mounds, dead trees, burrows in the ground, litter, pans and other temporary water will provide a holistic picture of the habitats in the area that support the recorded biodiversity.
The VCA sites as well as the biodiversity monitoring sites will be positioned so that they can provide information about the creatures and plants in every single land type in Kruger from mopane thickets to grasslands. Information will be obtained for the tops of hills, foothills and river fringes to cover all possible habitats. Scientific services has also identified areas like specialised riverine vegetation, sodic areas and rocky koppies where they intend to do specific surveys to record some rarer species.
At this stage, a lot of work is focussing on the nuts and bolts of the issue, to establish the cost-benefit ratio. With all the time and money in the world, a near perfect picture of the biodiversity can be obtained, but all involved have busy schedules and the best possible picture for the least expenditure of time and money is being worked out.
Although not finalised, the plan is to make over 50 intense biodiversity monitoring sites. The sites in the sensitive environments that are of vital importance to biodiversity are likely to be intensively monitored by scientific services each year, possibly with help from other researchers or organisations. The section rangers would be tasked with looking after the more than 500 sites that need less intensive monitoring, but provide a more complete picture of how the park’s ecosystem is functioning, doing each site once every three years.
All the chosen sites will be GPSed and will have permanent markers in place. When the biodiversity data begins to flow in, Kruger will have a remarkable amount of information that can be used to pinpoint any changes that management needs to be alert to. Conservationists have increasingly become aware that changes in the smaller species may reflect larger system changes.
The monitoring programme will supply the necessary information to evaluate the Thresholds of Potential Concern (TPCs) that Kruger uses in its adaptive management or ‘learning by doing’ approach. Kruger’s science awareness officer, Michele Hofmeyr, comments, “Conservation does not only involve charismatic species, but is mainly about habitat conservation. We need to know what is occurring in the habitat to understand the system more clearly.
Once the habitat is conserved, species numbers are allowed to fluctuate within predetermined limits (TPCs) before any management actions are taken. “The most challenging part is balancing human values and needs with ecosystem processes.”
After many days in the veld, the scientific services team now knows that the sun is hot, the best way to keep a pitfall trap clean when you bury it in the ground is to bury two buckets and pull out the top one when you are done, that blue tags are the least harassed by animals….and that there are a LOT of living things out there in Kruger’s veld.