## 4 Discussion  
### Hotspot Analysis  
The integration of GPS location data and RS imagery allows for spatiotemporal comparisons of sheep grazing preferences and vegetation conditions [1; 23]. Previous research by [PERSON] et al. [91] and [PERSON] et al. [12] showed that livestock expand their daily feeding areas in response to low forage availability. This relationship between grazing behaviour and vegetation condition can be used to predict the movement of animals and their preferred grazing areas. It can also be used to predict the grazing behaviour of sheep (and other livestock) across farms. Access to such information would greatly improve grazing management strategies and ultimately protect areas and plant species sensitive to overgrazing [1].  
In this study, six of the twelve grazing camps are bisected by drainage lines. The GPS data and hotspot analysis showed that the sheep prefer areas along drainage lines with higher vegetation vigour (higher NDVI), but expanded their foraging domain when placed in camps with less variability (no drainage lines). It was found that the drainage lines were utilized year-round by the sheep under all stocking densities and the sheep only utilized less than 20% of available grazing land when a drainage line is present. Drainage lines are therefore effectively exposed to higher stocking rates in comparison with the rest of the camp. The higher biomass in the drainage lines does not necessarily enable these areas to sustain selective overgrazing as this may harm the more palatable plant species, ultimately reducing the biodiversity [23; 92; 93].  
Although the effect of rainfall events on vegetation conditions was not the focus of this study, previous work [94] found strong correlations between rainfall variability and vegetation indices and that such indices accurately reflect vegetation production potential and rain use efficiency in semi-arid environments. In our study, the high-resolution Sentinel-2 imagery confirmed variability in vegetation conditions across the study area and over time. For instance, higher NDVI values were recorded in the drainage line areas and these areas also responded more swiftly to rainfall events in comparison to the grazing areas outside the drainage lines. Early summer rain in January resulted in increased vegetation activity, which is reflected in the NDVI values. This was observed from 2017 to 2020, except for 2019, when lower than average rainfall was received. The NDVI values clearly portrayed differences in vegetation cover and plant vigour, likely driven by higher soil moisture content, which is in accordance with the findings of [PERSON] [95], [PERSON] and [PERSON] [96] and [PERSON] et al. [97].  
A possible explanation for the sheep clustering in the drainage lines is the in situ observed denser vegetation layer in these areas. The plants are also more palatable. This is most likely due to the soils being deeper along the drainage lines. During field visits, it was observed that selective defoliation of specific plant species occurs, which suggests that vegetation cover is not the only driver of grazing behaviour. Although a detailed comparison between the measured soil properties and vegetation composition is outside the scope of this paper, it is clear from preliminary analyses that vegetation composition and density impacted animal behaviour and grazing selection. More work is needed to investigate how species composition and soil conditions impact grazing behaviour. The use of remotely sensed imagery for species detection and mapping should also be investigated. Identifying and mapping more productive areas across rangelands should assist land users to fence off these areas to prevent overgrazing. Understanding how small stock utilize drainage lines could assist in the sustainable use of these areas through improved management strategies such as fencing off these preferred grazing areas. This should be considered during farm planning processes on a large scale, but also on a camp scale when stocking rate is considered.