Remote Sensing and GIS Approach Detects Key Resource Areas for Large Herbivores in Kenyan Rangelands
Moffatt
Kangiri
Ngugi, Colorado State University/NREL, ngugi@cnr.colostate.edu
(Presenting)
Richard
Theodore
Conant, Colorado State University/NREL, conant@nrel.colostate.edu
Rangelands are extensive low productivity areas interspersed with a few high productivity zones referred to as Key Resource Areas (KRAs). KRAs serve as fall back areas forming “oases” of forage reserves during dry seasons which enable fuller use of extensive rangelands by bridging resource supply between times of abundance and scarcity. We ascertained the presence and use of KRAs as dry season foraging zones for large herbivores during fieldwork in Kenya. Published descriptions and our hypothesized expectations of KRA characteristics were tested using MODIS satellite data. We examined spatial and temporal green-up dynamics during 2000-2005. KRAs had high NDVI mean and variance relative to outlying rangeland (nonKRA). The coefficient of variation of NDVI was lower at KRAs. KRAs can be isolated from nonKRAs due to higher base NDVI values during the start of seasons, higher maximum NDVI and larger NDVI integral values which represent total production in a season. Ground truth reports confirmed production from woody biomass and perennial herbaceous biomass contributes to the higher NDVI in KRAs. Application of remote sensing is an objective method to identify KRAs in dry tropical ecosystems. This approach will strengthen inventory and monitoring of rangelands and may be applied in other rangelands to support management and conservation.