A BIOPHYSICAL FRAMEWORK FOR THE SUSTAINABLE MANAGEMENT OF WETLANDS IN THE LIMPOPO PROVINCE WITH NYLSVLEY AS A REFERENCE MODEL Report to the Water Research Commission by W VLOK1, CL COOK1, RG GREENFIELD2 D HOARE3, J VICTOR4 & JHJ VAN VUREN2 1University of Limpopo 2Johannesburg University 3 Consultant 4 SA National Biodiversity Institute WRC REPORT NO.: 1258/1/06 ISBN NO: 1-77005-462-6 APRIL 2006 This Report is obtainable from: Water Research Commission Private Bag X03 Gezina 0031 Pretoria, South Africa The Report emanates from a Water Research Commission project K5/1258: titled: A BIOPHYSICAL FRAMEWORK FOR THE SUSTAINABLE MANAGEMENT OF WETLANDS IN THE NORTHERN (LIMPOPO) PROVINCE WITH NYLSVLEY AS A REFERENCE MODEL DISCLAIMER This report has been reviewed by the Water Research Commission (WRC) and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the WRC, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. Nylsvley Executive Summary __________________________________________________________________________ EXECUTIVE SUMMARY Water in South Africa is a critically important natural resource. The Department of Water Affairs and Forestry list it as one of the most limiting resources in South Africa. South Africa is a semi-arid to arid region, receiving only an average of 500 mm of rain per annum, which is only 60% of the world average. Sixty five percent of the country receives less than 500 mm per annum, with 21% receiving less than 200 mm per annum. These conditions are further associated with highly variable climatic processes such as long periods of drought and floods, resulting in impacts on water resources that are difficult to manage. Jay O’Keeffe mentioned that the country’s rivers are often short and high seasonal flow regimes occur during the rainy season. The ecological value of wetlands is demonstrated by their physical and geological presence, shape and vegetation it supports. Wetlands control stream flow, attenuate the force of floods, store water, slowly releasing it over time and remove certain pollutants. The value of wetlands was previously not appreciated and the international trend was to drain wetlands. In 1996, Dr. Geoff Cowan (DEAT) estimated that more than half of the wetlands in South Africa had already been destroyed or otherwise lost. Where wetlands are destroyed in the catchment of a river, the likelihood of flooding can increase in the lower reaches, resulting in serious damage. The recent floods in the Limpopo Province, Mpumalanga and Mozambique are clear evidence of this fact and a large proportion of the damage can be attributed to poor wetland management. The lack of wetlands could not buffer or minimise the impacts of the floods. A possible reason for the lack of awareness of the importance of wetlands may be the fact that research on vlei’s and sponge areas in the past focused mainly on specific agricultural activities and related matters in catchment areas. This resulted in the fact that rivers and associated wetlands were merely considered as sources of freshwater to be utilised at will. Although there is an increase in public awareness of the environmental importance of water and the importance of conservation of the natural environment when developing water resources (Heath and Claassen, 1999), much must still be done to make the larger community aware of this aspect. This is especially important when one refers to wetland conservation. In semi-arid areas, it is critical to find a balance between water resource development and the maintenance of the natural environment (DWAF, 1995). At a workshop in 2000 on Wetlands in the Limpopo Province, a needs analysis identified the following five main areas for research: 1) a need to compile baseline information of wetland research i Nylsvley Executive Summary __________________________________________________________________________ in the Limpopo Province; 2) preparation and utilisation of information and knowledge in education and awareness programmes; 3) development of scientific information to assist in the management approach of these sensitive habitats; 4) development of expertise on vlei’s and sponge areas in the province (centre of excellence) and 5) to identify development potentials in the area. Nylsvley as a RAMSAR site is under threat. Recent studies have shown that the water quality is poor. During the last ten seasons, water bird numbers have shown a decline of 80-90% in Nylsvley, indicating deterioration in the wetland. It was also mentioned that the frog numbers have declined, as only a few calling frogs were heard in February, after the good rains in the Limpopo Province (Wetlands Workshop, 2000). A study in this area will assist the Limpopo Province Department of Finance and Economic Development (Environmental Affairs) to compile a management plan for the reserve. The Nylsvley project is proposed in an attempt to obtain a holistic perspective of the current state of the vlei area and to identify impacts that could lead to further degradation and also identify areas where restoration could be affective. A further important consideration for focusing in the area is that the Waterberg is registered as a Biosphere Reserve, making it an important international and national conservation area. The project will address various issues such as pollution from various quarters that have impacted on the resources and the effects of the increasing human population on the water quality in the area. Introduction: The project was initiated after a two-day workshop in 2000 hosted by Dr Steve Mitchell of the Water Research Commission near Nylsvley Nature Reserve. The aim of the workshop was to gather all role players to identify needs as far as biomonitoring of wetlands are concerned. After the consultation with the community, researchers and conservation agencies, a specialist workshop was held to compile the proposal for the project. Objectives: 1 To develop draft water quality guidelines in vlei areas for key variables/parameters. 2 To develop potential biomonitoring indices specific to vlei areas. 3 To compile a draft sustainable management programme, focusing on the biophysical aspects, for Nylsvley. 4 To propose a strategic management plan for sustainable utilization of wetlands in the Waterberg region. A further important aspect of the project was the building of capacity. The lack of scientists specializing in wetlands is still problem is South Africa. A result from the larger project to address ii Nylsvley Executive Summary __________________________________________________________________________ the problem is the completion of a PhD and two MSc studies. Various other students were involved in the project as research assistants, although the projects they completed as part of their studies focused on other areas. Summary of the different chapters: Chapter 1 is a summary of the different sites used during the study. A total of 18 sites were used, 10 for water and sediment sampling and 8 for the whole spectrum of water, sediment and biota. Chapter 2 is a comprehensive summary of the water quality study. A range of parameters was evaluated and compared to an earlier study that focused on the Nylsvley Reserve area only. In the latter study, sites in the upper catchment of some of the important tributaries were included. The idea was to use these sites to get some baseline water quality data to really be able to quantify the pollution of the water in the Nyl River system and the associated floodplain. Chapter 3 gives an overview of the potential pollutants in the sediments. This study was included to give some overview of the “pollution history” of the study area. Chapter 4 is focusing on pesticides as potential pollutants. During the initial phase of the project, it was assumed that metals formed the most important pollutants in the system. As the project developed, we have decided to investigate the possible impact of pesticides on the biota of the system. Chapter 5 is a summary of the work done on the macro-invertebrates of the whole system. The idea was to test the current indices used in the River Health Programme (RHP) to test its applicability to the Nylsvley area as a monitoring tool. The methodology and interpretation of the results were tested to evaluate the potential of SASS5 as a monitoring tool for Nylsvley and similar wetlands. Chapter 6 is included to give some view on the potential of frogs in particular as a monitoring agent for wetlands. The idea is to develop this work further into an index that can form part of a biomonitoring programme. Chapter 7 focused on the plants as monitoring organisms. The feeling was that the current Riparian Vegetation Index (RVI) used in the RHP is not practical and a more specific index must be developed. This is an effort to get a working document on the table. Chapter 8 is evaluating the Fish Assemblage Integrity Index (FAII) as a tool to monitor Nylsvley and similar floodplain areas. Chapter 9 is a proposed method to use the various indices from this project to get an overall picture of the health of wetlands. Chapter 10 an example of what a management plan must consist of and we used one of the main issues identified to illustrate the use of the framework. iii Nylsvley Executive Summary __________________________________________________________________________ Recommendations: This is a summary of the recommendations from the various sections in the report. Each author has highlighted the most important aspects. These recommendations form the basis for the management framework we have compiled for the management of Nylsvley in particular and the whole floodplain and the catchment areas contributing to this sensitive system. Towards the end of the project a flight in micro-light airplanes was undertaken to get a overall view of the study area in particular and a general impression of the area. It must be emphasized that this gave a huge insight into the system, its functioning and problems not picked up during normal surveys and traveling in the area.