Landscape functionality of plant communities in the Impala Platinum mining area, Rustenburg L. van der Walt a, * , S.S. Cilliers a , K. Kellner a , D. Tongway b , L. van Rensburg a a School of Environmental Sciences and Development, North-West University, Potchefstroom Campus, Potchefstroom 2531, South Africa b CSIRO Ecosystem Sciences, GPO Box 1700, Canberra ACT 2601, Australia article info Article history: Received 23 April 2012 Received in revised form 19 July 2012 Accepted 14 August 2012 Available online Keywords: Landscape function Soil surface indices Fetch-length Platinum mine tailings Thornveld abstract The tremendous growth of the platinum mining industry in South Africa has affected the natural environment adversely. The waste produced by platinum mineral processing is alkaline, biologically sterile and has a low water-holding capacity. These properties in the environment may constitute dysfunctional areas that will create ‘leaky’ and dysfunctional landscapes, limiting biological develop- ment. Landscape Function Analysis (LFA) is a monitoring procedure that assesses the degradation of landscapes, as brought about by human, animal and natural activities, through rapidly assessing certain soil surface indicators which indicate the biophysical functionality of the system. The “TriggereTransfer eReserveePulse” (TTRP) conceptual framework forms the foundation for assessing landscape function when using LFA. The two main aspects of this framework are the loss of resources from the system and the utilisation of resources by the system. After a survey of landscape heterogeneity to reflect the spatial organisation of the landscape, soil surface indicators are assessed within different patch types (identi- fiable units that retains resources that pass through the system) and interpatches (units between patches where vital resources are not retained, but lost) to assess the capacity of patches with various physical properties in regulating the effectiveness of resource control in the landscape. Indices describing land- scape organisation are computed by a spreadsheet analysis, as well as soil surface quality indices. When assembled in different combinations, three indices emerge that reflect soil productive potential, namely: the (1) surface stability, (2) infiltration capacity, and (3) the nutrient cycling potential of the landscape. In this study we compared the landscape functionality of natural thornveld areas, rehabilitated opencast mines and rehabilitated slopes of tailings dams in the area leased for mining in the Rustenburg area. Our results show that the rehabilitated areas had a higher total SSA functionality due to higher infiltration and nutrient cycling indices than the natural thornveld landscapes. The length of interpatches and the width of patches greatly influenced the landscape function of the studied areas. The natural thornveld areas had a marginally higher total patch area than the rehabilitated areas. Vegetated patches (grass-, sparse grass-, grassy forb-, and grassy shrub-patches) generally scored the highest functionality indices, whilst bare soil interpatches contributed to the landscape functionality of the various plant communities the least. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction The platinum mining industry has experienced tremendous growth in South Africa during the past fifty years, but also had an extensive negative effect on the environment. These effects include increased salinity of tailings deposits which could lead to contam- ination of ground- and surface-water, and dust emissions (Implats, 2010). According to a review on the course of the mining industry in South Africa by PricewaterhouseCoopers (2010), platinum group metals (PGM’s) has been the biggest revenue-generating commodity since 2005. Impala Platinum produces more than 1.74 million ounces of platinum annually, with the price per platinum ounce reaching about R10 089 (Implats, 2010). Platinum mines in South Africa exploit thin, shallow reefs extending over vast lateral areas (Campbell, 2006) through conventional underground or opencast techniques (Glaister and Mudd, 2010). The waste produced by platinum mineral processing is alkaline, biologically sterile and has a low water-holding capacity (Van Rensburg and Morgenthal, 2004). These properties in the environment may constitute * Corresponding author. North-West University, Potchefstroom Campus, Building E6, Potchefstroom 2520, South Africa. Tel.: þ27 (0) 82 182 9718; fax: þ27 (0) 18 299 2509. E-mail addresses: 20480628@nwu.ac.za, luts06@hotmail.com (L. van der Walt). Contents lists available at SciVerse ScienceDirect Journal of Environmental Management journal homepage: www.elsevier.com/locate/jenvman 0301-4797/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jenvman.2012.08.024 Journal of Environmental Management 113 (2012) 103e116