Abstract: The widespread environmental damage caused by slimes dam construction requires rehabilitation as one of the key management strategies towards land restoration. Most mines, however, focus on establishing a mere vegetation cover on the dams with no regard to their long-term ecosystem development. From the time when Mhangura Copper Mine was shut down in 2000 no follow up studies were carried out on the slimes dams to assess their development with respect to ecosystem function and long term recovery. A holistic approach involving an integration of different methods was necessary for such an evaluation to be undertaken. The Landscape Function Analysis (LFA) method was thus
combined with remotely sensed NDVI data to achieve this end. The data were first
analysed using LFA software packages and then with various multivariate statistical
analyses. There was a marked difference in species composition between the rehabilitatedslimes dams and the natural Acacia woodland. Hyparrhenia sp. was the dominant grasson Dam 5 and Imperata cylindrica dominated Dam 6. The tree layer on the slimes damswas not as developed as the grass layer. Nevertheless, Acacia saligna was the most abundant tree species on the dams. The rehabilitated slimes dams converged with the natural woodland for the LFA indices of stability, nutrient cycling and infiltration which suggested a high level of functionality. NDVI images taken over the years 1990, 1994, 2000 and 2010, depicted a progressive increase in vegetation cover. This was supported by the statistical analyses which showed a change in NDVI over the years though no actual trend was provided. The main factors affecting the sustainability of the rehabilitation were identified to be fire, grazing and tree harvesting. These data, however, did not provide a definite judgement of rehabilitation success or failure. The need for future monitoring to ascertain long term sustainability was suggested. Faunal surveys, comprehensive remote sensing monitoring and a study on the role of microbiota were
also recommended. The study contributed to the importance of and methods used for assessing ecosystem function on rehabilitated slimes dams in Zimbabwe, often ignored as most focus in on the establishment of plants on the dams.
