## 1 Introduction  
Land cover change is the leading global cause of species extinctions [1]. Humans have significantly altered 75% of the earth's surface, with over one third of the terrestrial land surface currently being used for cropping or animal husbandry [2, 3]. Hotspots of biodiversity have, on average, been more altered and degraded than other areas despite their importance [1]. The Cape Floristic Region (CFR) of South Africa is one such global biodiversity hotspot [4]. The CFR covers 90,000 km\({}^{2}\) and is home to around 9400 plant species, 68% of which are endemic [5]. This incredible plant species richness makes the CFR the most floristically diverse region of the world outside of the tropics [6]. The CFR is characterised by very high fine-scale habitat partitioning among species (beta diversity) and turnover of species in space (gamma diversity) [7]. Species within the CFR are thus inherently vulnerable to extinction through habitat loss, as many have narrow environmental tolerances and small range sizes [8, 9]. Within the CFR, the vegetation characteristic of the lowlands is known as Renosterveld. Renosterveld typically occurs on fertile, shale-derived soils and has a significant grass component. Due to the association of Renosterveld with soils and topography suitable for agriculture, an estimated 90-94% of its original extent has been completely transformed into intensively cultivated dryland crops: predominantly wheat, canola and barley [10, 11, 12]. Sheep are grazed on fallow fields and rotational crops as well as Renosterveld patches, further degrading the few remaining intact fragments. As a result of this historical land cover change and habitat degradation, the Renosterveld contains perhaps the highest concentration of threatened plant species of any continental region globally [13; 14; 15; 16]. Within the CFR as a whole, 1893 plant species are threatened with extinction, with many of these restricted to Renosterveld [11]. Of the 29 Renosterveld vegetation types described, 17 are listed as as either Critically Endangered, Endangered or Vulnerable according to South Africa's National Environmental Management: Biodiversity Act No 10 of 2004 (NEMBA). This act is intended to safeguard these ecosystems, ensuring formal protection and mandating restrictions on any loss of natural habitat. Further protection is given by the Conservation of Agricultural Resources Act, 1983 (Act No. 43 of 1983) (CARA). This act precludes the cultivation of virgin soil, defined as soil undisturbed for over 10 years, without prior authorization. Despite this legal protection, and concerted conservation efforts (e.g., the Cape Action for People and the Environment programme (CAPE) and the Overberg Renosterveld Conservation Trust), land cover transformation within the Renosterveld continues unabated [17; 18]. Recent estimates suggest that up to 1% of what remains of the Renosterveld has being lost each year between 1990 and 2014, with extermination expected to be completed in less than 75 years if these rates continue [11]. It was thought that historical rates of vegetation loss were unlikely to be maintained as the fragments of Renosterveld which do remain occur within areas that are less suitable for agriculture, with steep slopes or rocky soils [19]. However, improving technology and deteriorating economic conditions can render areas previously thought to be of minimal agricultural value vulnerable [10; 19; 20]. In order to prevent the loss of the last remaining fragments of Renosterveld, conservation management agencies and environmental law enforcement require timely and accurate information on the location and timing of land cover transformation. This information can help identify the proximal and ultimate drivers of vegetation loss and identify areas that may be susceptible to future change. In recent years new algorithms and an increase in the availability of remotely sensed data have improved the temporal and spatial resolution at which land cover change can be monitored [21; 22; 23; 24].