## 2 Materials and Methods
### Dating of Change Events  
High temporal frequency PlanetScope imagery was used to determine the date on which loss occurred for each parcel where loss was confirmed between February 2016 and January 2020. The removal of Renosterveld within a parcel can take multiple days or weeks to be completed, and even if removal occurs instantaneously multiple days or weeks can elapse before cloud-free image becomes available in which it is possible to confidently confirm that natural vegetation is no longer present. Two dates were therefore assigned to each parcel to describe the temporal nature of Renosterveld loss: the latest date on which it was possible to confirm that intact Renosterveld was still present, and the earliest date on which it was possible to confirm that intact Renosterveld was no longer present. Determining these dates depends on the revisitation frequency of satellite platforms, atmospheric conditions, which determine the image useability, and the nature of land cover change (Figure 2). The near-daily global imaging capability of the Planet satellite constellation and low cloud and haze over this region for much of the year provide sufficient images for these dates to be determined within a few days of each other for many of the Renosterveld loss events detected. The mechanism through which Renosterveld is converted to non-natural land cover, and whether change is continuous or punctuated, influences how discernible land cover change is when examining satellite image time-series'. This in turn influences how accurately loss events can be dated. Given an abrupt disturbance that removes a large amount of aboveground biomass and disturbs the soil surface-such as ploughing-the last date of Renosterveld presence and first date of its absence can be determined within a few days if sufficient imagery is available. Gradual vegetation degradation through continual overgrazing can result in the loss of Renosterveld over a period of multiple years or even decades. This type of land cover change is poorly captured by the approach used here. To assign dates to each parcel of Renosterveld loss the approximate month and year in which loss occurred was determined using monthly global surface reflectance basemaps available from Planet labs. Once this month was determined, time series' of daily imagery were examined to determine the last date of Renosterveld presence and first date of its absence (Figure 2) using the Planet Explorer online platform. Only those Renosterveld loss parcels in which these two dates could be confidently determined within 10 weeks of each other were used in subsequent exploration and analysis. The rate of loss through time between 2016 and 2020 was examined using the dates assigned and allowed the months and years in which high and low rates of loss occurred to be determined. The size distribution of change events was also explored providing insights into the nature and size of events that contribute most to total loss. Plotting the location, date and size of loss events spatially aided in identifying hotspots of land cover change with the Overberg Region.  
Code and data used in this analysis are available at www.github.com/GMoncrieff/renosterveld-data www.github.com/GMoncrieff/renosterveld-change. Due to ongoing investigations location data have been removed to protect the identity of landowners where necessary.