Spatial and temporal patterns of elephant distribution in Marsabit National Park and Reserve, Kenya

Changing land use patterns next to protected areas (PAs) is a major threat to wildlife dispersal areas and migratory corridors. In most countries including Kenya, the PAs have become habitat "islands". As a result, this affects the net energy maximization strategy by wildlife including elephants as described by the optimum foraging theory. The decisions on which habitats to use, which specific feeding sites within the habitat to visit, and the migratory routes to follow is expected to conform to the optimum foraging theory. This theory has been tested in wild ungulates and information well documented. However, much attention has not been focused to the mega-herbivores. We aim to establish whether the optimum foraging theory is applicable to migratory mega-herbivores like elephants.

We seek to answer whether habitat selection, movement pattern, and distribution of elephants in Marsabit National Park/Reserve are influenced by biophysical and human factors. The specific objectives of the study are to: Map actual and potential elephant habitats, establish and explain the spatial and temporal patterns of elephant distribution, establish and explain the movement patterns of elephants, quantify habitat selection by elephants, identify and establish the quantity of plant species utilized by elephants, measure their foliage quality and inhibitors, and predict and simulate the future distribution of elephants in Marsabit National Park/Reserve and adjoining environment.

Appropriate expert knowledge neural networks will be designed and used to isolate the actual and potential elephant habitats from an ASTER satellite image taken on 3rd March 2004. Elephant distribution will be obtained from 5 male and 5 female elephants collared with satellite linked GPS collars. Biophysical data layers to be used in the analysis will include elevation, slope, drainage system, NDVI and soils. Human data layers will include distance from settlements, and distance from minor and major roads. Clustered random sampling strategy will be used to establish quadrants for identifying and quantifying plant species consumed by elephants and collection of image classification data. We aim to contribute towards the understanding of the "insular ecology" of elephants within the eutrophic savanna-forest fragmented ecosystem interface.

Summary of the results so far

60,469 GPS points have been collected from 9 collared elephants. The elephants exhibit a clustered distribution pattern all the year round. They cluster around water points and specific feeding grounds. They occur close to human settlements. During the wet season, they move to the lowlands. As water dries up during the dry season, they move back to the highland where there are permanent water points. The highest point an elephant was recorded during the dry season is 1694m a.s.l, while the lowest is below 500m a.s.l.