Rangeland resources assessment with satellite imagery: an operational tool for national planning in Namibia

Type Journal Article - Geocarto International
Title Rangeland resources assessment with satellite imagery: an operational tool for national planning in Namibia
Author(s)
Volume 20
Issue 3
Publication (Day/Month/Year) 2005
Page numbers 33-42
URL http://www.tandfonline.com/doi/abs/10.1080/10106040508542353
Abstract
The Namibian authorities endeavour to implement a rangeland resources management policy at national level. The first line of action is the allocation of livestock marketing priorities to the most drought‐affected areas. Another potential application is the estimation of land value in terms of grazing capacity, as a base for land purchase and redistribution for private land taxation. Accurate and up‐to‐date information on the resources, which are very variable in time and space, is indispensable for rational and efficient decision‐making. In this regard, low‐resolution satellite imagery appears to be a practical and suitable source of data for non‐biased and reasonably accurate estimation of forage production over the whole country. Using 17 years of AVHRR and VEGETATION satellite data over Namibia, seasonal biomass production estimates were obtained with a simple but operational vegetation production model known as the Monteith model. The accuracy of the products was assessed by comparison to field measurements carried out between 1999 and 2001, showing good correspondence and a residual error of approximately 25% of the average. Long‐term averages of biomass production from all available satellite data (17 growing seasons) give an indication of the “normal” potential of the land in terms of grazing. This can be used for marketing priority allocations, the comparison of the production of the current season to the long‐term average allowing to identify the most problematic zones and to quantify the severity of a crisis. The long‐term average is also a good base for land value assessment, although complementary processing is required. The products are integrated in a GIS environment to be used with complementary geographic information. The potential of such a system for decision making within the Namibian range resources management policy is discussed.

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