Daily herd movements across the wet and dry season in the semi-arid communal rangelands of Namaqualand, South Africa

Abstract

The role of indigenous grazing management practices in sustainable natural resource use has been widely identified and recognised in the literature. However, the grazing management practices of Nama pastoralists in the semi-arid regions in Namaqualand in South Africa have not been adequately studied in terms of GPS-based seasonal grazing distribution. This study aimed to assess the seasonal livestock grazing distributional patterns across three communal rangelands in Namaqualand using GPS collars. The objectives were to: (1) generate grazing distributional maps to identify patterns of seasonal rangeland use, (2) compare area covered at different grazing intensities of livestock between seasons, (3) delineate different grazing zones at different times of day, and (4) contrast seasonal differences within these grazing zones regarding grazing activity. CatLog GPS collars were mounted on livestock and T-LoCoH R package and Google Earth were used to generate grazing distribution maps showing areas most and least frequently used by livestock and daily movement patterns. The results showed that Namaqualand herds grazed only a small proportion (21.1%) of their mean home range (809.6 ± 76.2 ha) at high and moderate grazing intensities, regardless of season, corresponding to areas of 48.1 ± 13.5 ha and 287.7 ± 41.60 ha, respectively. In the wet season, herds used a 16.8% larger area than in the dry season. The area associated with high grazing densities was significantly smaller than areas grazed at lower grazing pressure. No significant differences in mean area associated with seasonal variation within each level of grazing suggests herders are not seasonally altering areas associated with high grazing intensity, which are sometimes associated with permanent water sources. It is also likely that herders are concerned about ensuring their livestock have sustained access to optimal forage sources by avoiding other flocks using the same areas. Grazing activity is indirectly proportional to grazing speed. Grazing activity is lower in the herded zones (the morning–excitement/appetite moderation zone and the early afternoon–target zone, mean speed = 0.955 ± 0.006 km h−1) than when in an unherded zone (late afternoon–late afternoon meal, mean speed = 0.852 ± 0.010 km h−1). Mean distance travelled daily by herds in the herded zones was greatest (4.773 ± 0.029 km). In the wet season (7.365 ± 0.055 km) and a greater area was covered daily (10.6 ± 1.2 ha) as resources become more abundant relative to the dry season. This suggests that indigenous herding practices in Namaqualand require ecologically aware decision-making processes associated with effective resource use. Contemporary grazing management policies should be more inclusive of indigenous management as aspects of holistic grazing management have been embedded in these practices for centuries.