The Role of Riparian Corridors in the Savanna Landscape of South Africa

A Cooperative Research Program Between: The University of the Witwatersrand, University of Washington, Institute of Ecosystem Studies, Kruger National Park, University of California-Berkeley

INTRODUCTION

This program will provide a thorough understanding of the structure and dynamics of riparian corridors and the role they play in the savanna landscape. In South Africa, savanna landscapes are important reservoirs of biodiversity in tropical and subtropical zones, and are affected by expanding human populations and shifting patterns of land use. In order to understand and manage savanna landscapes, several concepts must be employed. Foremost is the application of a modern systems viewpoint (e.g., Likens 1992), which hypothesizes the spatial and temporal heterogeneity of savannas as key to their function (Rogers 1997). The systems approach requires ecologists to expose the connections and fluxes between the elements of heterogeneity, their effect on biodiversity, and the feedbacks between heterogeneity and ecosystem function (Risser 1997). Therefore, boundaries in the landscape that designate this heterogeneity are of particular ecological interest. We choose to focus on riparian corridors because they are perhaps the most obvious expression of boundaries in savanna regions. They are recognized as "hotspots" of activity because they integrate terrestrial and aquatic systems (Naiman and Décamps 1997). However, the functional interactions between riparian zones and the adjacent upland savanna have been neglected. The research we propose will generate a novel understanding of savannas as integrated yet heterogeneous ecological systems.

OBJECTIVES

Our program has three major objectives. The first objective approaches the riparian and savanna uplands as parts of an interactive system.

Objective 1: Develop an understanding of the functional relationships of riparian corridors to the savanna matrix.

Because riparian zones have primarily been considered in relationship with streams rather than the larger landscape, this objective requires new approaches to riparian systems. In particular we have the following research goals:

a) Investigate the origin and structure of landscape heterogeneity in which the riparian zones exist;

b) Document key processes in the riparian zone; and

c) Determine the interactions of processes in the uplands with processes in the riparian zones.

Objective 2: Our educational objective is to diversify future generations of South African and American ecologists.

Because improved scientific understanding of riparian-upland systems, and understanding of ecosystem processes in South Africa, are limited in part by the small number of trained ecologists in the region, our second objective addresses this need.

Objective 3: Integrate the new scientific knowledge into the management of the KNP.

The third objective arises from a need to be good citizens within the KNP where the research will be conducted, and to test the validity of our emerging scientific understanding by relating it to management of the Park.