TEMBO in the Timbavati
By Michele Hofmeyr and Raymond Travers
So you are driving along in your car in the Kruger National Park and you ponder the fact that elephants eat about 180kg of vegetation per day. Where on earth do all the KNP’s elephants find 180kg of vegetation to eat each every day? Kruger National Park scientists have also been pondering this interesting question too. Perhaps more specificially, what they have been asking relates to the distribution of elephants and other herbivores in conservation areas in relation to the nutrient status of the vegetation and now they hope that TEMBO can give them the answers.
TEMBO, or more specificially, the elephant movements and bio-economic optimality programme, is a five year programme run jointly by the Wageningen University in the Netherlands and the University of Kwa-Zulu Natal. The project is funded by WOTRO (a Dutch funding agency for research in the tropics). The main objective of the TEMBO project is to predict the distribution of elephants in conservation areas in relation to the nutrient status of the vegetation, in order to carry out a cost-benefit analysis for the optimization of resource management for commercial purposes and conservation.
Ecologists from SANParks Scientific Services in the Kruger National Park visited the projects TEMBO are currently running in the Timbavati Private Nature Reserve. The group was shown various sites by Cornelis van der Waal and Yolanda Pretorius, both TEMBO PhD students working in the Timbavati.
In the main experiment, various sized plots had been fertilized with three different levels of phophorous and nitrogen from low to high concentrations. The size of the fertilized patches varies from 2x2m to 50x50m in size. This experiment is conducted in an area of 30 ha on the farm Sumatra in the Timbavati. The purpose of this study is to investigate how differences in soil nutrient availability (soil fertility) affect grass production and palatability or tastiness. These plots will also show the different responses of trees and grasses to fertilizer applied in small and large patches in the in low nutrient mopane savannas. The experiments will also look at the effect of fertilization on the shoot growth and leaf numbers of mopane trees. The soil nutrients also influence the quality of the grass, which in turn will influence the types and numbers of animals that will come to the area to graze.
The second site shown was an exclosure experiment where 1m x1.5m cages keep out herbivores from the fertilized patches of grass and make it possible to see the effect of fertilization on grass production and utilization. The preliminary results show that fertilization increased grazing off-take more than 10 fold.
A third project currently running in the Timbavati is looking at how animals utilize these fertilized patches. This research is being conducted by Yolanda Pretorius. This project will look at how foraging behaviour of different body sized herbivores is affected by patch size and nutrient concentration. To do this, Yolanda is counting spoor and dung piles in cleared sand areas near fertilized patches, while also monitoring how long it takes for dung piles to decompose. The results so far are showing that for the most abundant herbivore species in the area, larger animals such as buffalo select large fertilized patches while smaller herbivores like impala are more sensitive to local nutrient concentration.
“It is very useful for us to see the results of these fertilization experiments in reserves neighbouring the Kruger National Park” said Dr Rina Grant, Systems Ecologist for Scientific Services, based in Skukuza. “We are interested in how nutrients affect the distribution of animals in our savanna systems and considerable information can be gained from detailed experiments such as these. We can use these findings to better understand changes in the system and build these into our monitoring programmes that in turn inform management plans” explained Dr Grant.