Stocking density and distribution in relation to vegetation in a biodiverse semi-arid pastoral system in South Africa
M. Igshaan Samuels A B C * , Nicky Allsopp D and M. Timm Hoffman B
+ Author Affiliations
- Author Affiliations
A Agricultural Research Council – Animal Production, Biodiversity and Conservation Biology Department, University of the Western Cape, 7535, South Africa.
B Plant Conservation Unit, Department of Biological Sciences, University of Cape Town, 7701, South Africa.
C Biodiversity and Conservation Biology Department, University of the Western Cape, 7535, South Africa.
D South African Environmental Observation Network (SAEON), Fynbos Node, Claremont 7735, South Africa.
* Correspondence to: isamuels@uwc.ac.za
The Rangeland Journal 44(1) 1-12 https://doi.org/10.1071/RJ21046
Submitted: 18 August 2021 Accepted: 17 January 2022 Published: 7 March 2022
© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the Australian Rangeland Society. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)
Abstract
The spatial heterogeneity of vegetation in a communal grazing system provides pastoralists with a range of grazing sites to select for their livestock. When fencing spatially constrains herds, there is reduced access to ecological heterogeneity, which may have a negative impact on livestock and the grazing resource. This study investigated temporal and spatial changes in stocking densities and distribution within the six major vegetation types of the Leliefontein pastoral area in Namaqualand, South Africa. This semi-arid, biodiverse area of about 2000 km2 supports a spatially-constrained mobile pastoral system based on small stock production. Over the data period from 1999 to 2006, the location of 256 small stock herds, their temporal occupancy and herd size were used to determine stocking densities within the daily grazing radius of herds. These grazing radii were overlaid using GIS to produce stocking density distributions over the landscape. The density and location of herds were unevenly distributed when assessed monthly and annually. Parts of the study area were consistently overstocked whereas others remained ungrazed. We argue that the recommendation of fixed stocking rates within this variable environment is inappropriate because forage availability and quality fluctuate within and between years and within drought cycles. We conclude that development interventions should rather focus on reducing stocking densities during and after drought periods. This would benefit pastoralists through reduced livestock mortalities and the vegetation would recover more quickly from the impacts of drought.
Keywords: drought, grazing management, landscape ecology, livestock mobility, Namaqualand, overstocking, semiarid shrublands, spatial variation, stocking rate, Succulent Karoo.
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