ABSTRACT This study examined plant diversity status and the impact of drivers of change on the Kromme Peatlands in 2006. Species diversity was assessed using Whittaker plots. Ordination techniques were applied to determine species-environment relationship. Land use dynamics were assessed using GIS techniques on orthorectified images. Six peat basins were subjectively classified into good, medium and poor condition peat classes. This classification was based on the extent of disturbance on the vegetation. In the good peat basin (Krugersland), the vegetation was mostly diverse (4.1 Shannon's mean index) followed by medium class (Kammiesbos) (3.8 Shannon mean index) and poor class (Companjesdrift) (2.5 Shannon mean index). Species were not evenly distributed, since 77.8% of the Shannon's evenness index was < 1. There were variations in species richness. Species distribution and composition were influenced by grazing intensity, alien invasive, K, P and Ca²⁺. Total species variance accounted for first two axes was 40.7%. Analysis of images showed a progressive decrease in Peatland between 1942 (5.3%) and 1969 (8.3%) in the good and poor classes, with marginal increase from 1969 (1.5%) to 2003 (4.1%). Annual net rate of change over 61 years was -0.32% and -0.79% respectively. Invasive species in Peatlands increased by 50% between 1942 and 2003. Yearly net rate of change was +0.82% (good class) and +1.63% (poor class). Conservation measures such as clearing of alien invasive species, grazing regulation, construction of gabions (to in improve ground water infiltration, uplifting water table, as well as mitigate the extent of damage caused by floods) in 2003, helped reclaimed large parts of the peat basin that were lost. The continuous implementation of these conservation measures, could greatly improve on the functional status of the peat basin, especially as a carbon sink. KEYWORDS: Peat lands, species richness, diversity, condition class, species invasion, CCA, Cluster analysis INTRODUCTION Peat is sedentarily accumulated material consisting of at least 30% (dry mass) of dead organic material (IMCG Global Peatland Database). Grundling et al. (2004) defines peat as a brownish-black organic soil that is formed mostly in acidic, anaerobic wetland conditions, and comprises partially decomposed, loosely compacted organic matter. The importance of peatlands especially as carbon sinks, has been recognised by the European Union, and has subsequently identified a number of bogs as priority habitats for conservation under the Habitats and Species Directive (Wildlifetrust.org.uk). About 11 peatland eco- regions have been identified in South Africa (Marneweck et al. 2001).The Kromme peat basin is formed from palmiet-fen and are used for pasture and orchard farming. Ins pite of their importance, peatlands are reportedly threatened through erosion (Grundling et al. 1998 ), fire (Grundling et al. 1999) and alien vegetation (Haigh et al. 2002). Grobler et al. (2004) revealed that anthropogenic disturbances such as crop cultivation, fire, peat drainage, and the cutting/clearing of natural vegetation, have rapidly dwindled the once pristine peat swamp forest in the Kosi Bay Lake system in South Africa. The overexploitation of certain species, the introduction of exotic species, and the pollution or toxification of the soil, water and atmosphere have had major effects on South Africa's terrestrial, freshwater and marine biodiversity (White Paper on South Africa's Biological Diversity, 1997). Historically, the Kromme River land users changed from being predominantly pastoralists to commercial orchard farmers from about 1775 until present times (Haigh et al. 2002). More than 60% of the wetland catchment has been damaged beyond repair due to agriculture, channel and bank erosion and the proliferation of alien vegetation at the expense of conservation and rehabilitation (Natural Bridge Communications, 2005). This research work therefore attempts primarily to investigate the extent of the threat to plant diversity, emanating from anthropogenic activities and natural causes that the Kromme River Peatland Complex is experiencing and to suggest possible measures of restoring its natural functioning status. The study also seeks to find baseline information on the plant diversity potential of the wetland. MATERIALS AND METHODS Study area The Kromme River drains the Kouga Mountains eastern part of the inter-montane valley within the Cape Fold Belt, following a long inter-montane valley around the town of Kareedouw, and flows eastwards into the Indian Ocean west of Humansdorp at St. Francis Bay. The proposed study area is located between latitudes 33° 55` S and 33° 59` 15`` S, and longitudes 24° 15` E and 24° 26` 20`` E above the Churchill Dam (34° 05` S and 24° 29` E) (Figure i). The 48 km long peatland complex is situated upstream of the Churchill Dam, around the town of Kareedouw in the Eastern Cape Province. The altitude of the upstream basin is in the range of 350 to 300 m above mean sea level, with an average slope of 0.6% (Haigh et al. 2002). The geology of the area is dominated by quartzites and granites of the Cape Supergroup. The Kouga Formation (300 to 400 m) follows distinctive white quartzitic sandstone, with subordinate shale horizons forming the bedrock of the Kromme River basin. The predominant soil type is dark organic-rich loam within the Science Journal of Environmental Engineering Research ISSN:2276-7495 http://www.sjpub.org/sjeer.html © Author(s) 2013. CC Attribution 3.0 License. Published By Science Journal Publication International Open Access Publisher Research Article Land Use Changes and Their Impacts on the Vegetation Kromme River Peat Basin, South Africa C. A. Nsor¹ and J. Gambiza² ¹C/O Mesuna Sualihu, Deliman Oil Company, Box 6871, Accra-North, Ghana. ²Department of Environmental Science, Rhodes University, Grahamstown 6140, South Africa Volume 2013, Article ID sjeer-166, 12 Pages, 2013. doi: 10.7237/sjeer/166 Accepted 21�� March, 2013 Corresponding Author: C. A. Nsor Department of Environmental Science, Rhodes University, Grahamstown 6140, South Africa Email: ayineus@yahoo.com