Biodynamics of the
Eastern Cape Thicket Biome

Introduction

Project overview

The Terrestrial Ecology Research Unit (TERU) of the University of Port Elizabeth is contracted to complete the Eastern Cape sector of the Conservation Farming project being run by the National Botanical Institute. The project aims to compare the impacts of traditional and innovative "biodiversity-friendly" farming methods on biodiversity and ecosystem processes in agricultural landscapes across South Africa. The project was initiated in April 1999 and is due for completion in December 2002.

Two PhD students, Ayanda Sigwela (Zoology) and Richard Lechmere-Oertel (Zoology and Botany), are currently working on quantifying the changes in ecosystem function and biodiversity on farms with different management histories. Their projects are being supervised by Graham Kerley and Richard Cowling of TERU. Louise Visagie, an MSc graduate from Stellenbosch University, has joined TERU on a two year contract to assist on all aspects of the project.

Soil ecology and biodiversity

Richard Lechmere-Oertel is working primarily on quantifying changes in the soil ecosystem, particularly soil-water retention and run-off and the implications of micro-climate changes on decomposition processes. Thus far, experiments designed to capture run-off from 100m² catchments have been established on several fence-line contrasts. Litter traps, bags and packs have been set out to measure litter fall and decomposition over 15 months in several sites across and degradation gradient. A series of climate data loggers will be established in these sites to measure micro-climate inside and outside of bushclumps. During this period, plant and faunal diversity assays will be conducted as well as a several of soil chemical and physical analyses.

Plant reproductive dynamics

Ayanda Sigwela is assessing plant sexual reproduction, focusing particularly on seed and seedling dynamics. He is testing the hypothesis that large mammals are important dispersers of thicket seeds. Seeds are being extracted from samples of elephant, rhinoceros, buffalo, eland, kudu, bushbuck, and duiker faecal material collected from Addo Elephant National Park. Bird latrines have also been set out along the degradation gradient to quantify the potential of birds to disperse seeds into degraded areas. Ayanda has measured the abundance and microsite environment of seedlings across the degradation gradient and has set up experiments to measure death due to predation or environmental stress. Soil seed banks will also be quantified.

Vegetation dynamics and rehabilitation

Much of this work is aimed at understanding the dynamics of Succulent Thicket with the ultimate aim of looking for a path towards rehabilitation. This will benefit many farmers who have reduced their goat stocking rates and are moving towards farming game animals.