Keywords 
Elephants, preference, forage, crops, habitat 
Introduction 	gather food by elephants can best be described as 
	Over the last thirty years literally hundreds of 	hierarchical system of diet selection. A feeding 
	studies on African elephants (Loxodonta 	pattem established for one area cannot be 
	a/ricana) have been carried out across the 	extrapolated to another area. Selection of fora.ge 
	continent. The feeding ecology of the largest 	by African Elephants according to tree species 
	land mammals has attracted much attention, not 	has been reported by ~everal authors in other 
	only for the sheer quantity of food consumed, 	national parks. On a daily scale, intake rates are 
	but also the variety of plants selected and their 	limited by digestion and excretion, and the 
	impact on vegetation (Sukunw, 2003). 	amount of time investod for fureging· On a fin: 
	Herbivores have long been known to 	scale, consumption rates are inf1uen~ .bY . e 
	demonstrate preferences for different plant 	morphological properties and spatial dlstnb:lon 
	species and individual plants within a species. 	of plants (Shipley et al., 1994). In small f °h~er 
	. 	ifi parts 0 t el 
	Also the average food plant quality selected by 	ranges, elephants may use speci c es 
	different herbivores has been shown to be greater 	ranges more intensely than in large horne r~~ 
	than the average found in the environment (Laws 	and therefore impact may.be more irItens~. haDt 
	& Belovsky, 2010). Due to the biological 	it may be more appropnat~. to ?efine ~ ~Pns or 
	necessities of their immense body size, elephants 	impact in terms ofrange utll~zat!On n:: I;er se 
	have a key ecological role that is defined by their 	densities rather than populatton nurn ers 
	need for great quantities of food, water and 	(Junker et al., 2008). 
habitat. The grazing/browsing process used 10 
	
Journal o/Technology & Socio-Economic Development 

Forage preference by African elephants (loxodonta africana) in rimoi national game reserve, Keiyo County, Kenya 

Koskey Joseph Aruseyl',Okeyo Owuor J. B.Z, Sudoi v), Koskey, S. J.4, Saina A. K. 5 IDepartment ofWil~life Management, Narok University College, Narok, 2Dep~ment ofEnvironrnental Biology and Health, Chepkoilel University College, Eldoret, 4Ministry of Education, Eldoret west District, Eldoret, 5Department of Electrical and Electronics, Eldoret Polytechnic, Eldoret, Kenya. *Corresponding author Email: kO!iiose@yahoo.com
Abstract 
The feeding ecology of the largest land mammals has attracted much attenti'on, not only for the sheer quantity of food consumed, but also the variety of plants selected and their impact on vegetation. With continuous loss of habitat, qualitatively as well as quantitatively, elephants are forced to extend their range. This study was carried out between April and November 2010. The data on preferred forages by elephants were obtained by making a systematic record of the feeding behaviour. Their diet was deduced from records of plants which showed obvious signs of recent elephant use. The collected data were coded in Statistical Package for Social Sciences (SPSS ver. 17.0) and analyzed by descriptive methods. Results showed that the most preferred wild forage were Acacia tomlis (22.5%) followed by Balanites aegyptica (14.8%), then Acacia mellifera (9.6%) and Zizyphus mucronata (7.5%) and Acacia brevispica (7.1%). Elephants too showed preference for crops. There were significant differences in the crop raiding patterns ("l = 36.443, df'= 5, P = 0.0003). Based on the findings, the most preferred crops and therefore most raided was maize (86.5%) followed by millet (51.4%) and green grams (34.8%), while the least raided crops were cowpeas (16.8%) followed by millet (7.3%). This study showed that elephants consume different plant species with varying degree of preference. The daily diets of African elephants in Rimoi conservation area were selected entirely from the indigenous vegetation. Nineteen wild plant species viz., Acacia "'(ortilis, Balanites aegyptica, Acaia mellifera, Zizyphus mucronata, Acacia brevis pica, Acacia hamulosa, Acacia obyssintca. Combretum spp., Grewia bicotor, Cissus rotllndifo/ia, Cynodon dactylon, Eragrostis minor, Achyranthes aspera; Sanseviera intermedia, Sarcostemma viminale, Grewia mollis, Chloris pycnothrix, Ficus spp. and Aloe spp. were used in different ways by elephants as food in this region. Results also showed that the use of the plant species is more skewed towards the acacia plants and is likely to affect the normal functioning of the ecosystem, which indicate that elephants would be implicated in vegetativn change in structure and composition through their varied seasonal choice of food items that include fellin~ 
and debarking in the dry season. 
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Materials and Methods 
This study was done in Rirnoi National Game Rese~e and J(9Jlservation Area (RNGRCA) situated in Keiyd'County. Keiyo County is fourty seven counties in Kenya. The County has a total area approximately 1,439 km2 (GoK, 2001). It borders West Pokot County to the north, Baringo County to the east and Uasin Gishu County to the west (Fig. 1.1). Administratively the district is divided into five divisions, namely Chepkorio, Kamariny, Tambach, Soy and Metkei. It lies between 35°25' and 35°45' East longitudes and between 0°10' and 0~52' North latitude (GoK, 2002). Rimoi National Game Reserve is situated in the Kerio valley floor in the Keiyo/Baringo boundary. It is situated between longitudes 35° 30' and 350 40' East and latitude 0 0 40'and 0°50' North. Regionally, it is located in Rimoi and Tambach Divisions of Keiyo County (figure 3.2). RNGRCA is about 404 square kilometres which is approximately 35% of the entire County. RNGRCA is bounded by the Kerio River in the east which also separates Keiyo and Baringo Districts, and the Keiyo escarpment on the western part with the top of the escarpment (the highlands) extending as far as the Uasin Gishu border. The boundary of the Reserve, which is the critical zone of Rimoi NRCA, is marked to the northern-end by River Emsos while to the south by River Kessup. Rimoi National Game Reserve is a trust-land area of 66 square kilometres, generally flat and is part of the Kerio Valley basin - locally called Soin (or Tir'ngwon'gwo or Soiwo), that portion lying adjacent to Endo (River Kerio). The official boundary of theNational Game Reserve are delineated on a boundary plan No. 216/46 and was gazetted through legal notice number 13 of 26th January, 1983. The County Council of Keiyo is the Government body that is responsible for the management of the Rimoi National Game Reserve with technical advice from the Kenya Wildlife Service. 
Rainfall distribution in Keiyo County is highly influenced by altitude. In highland plateau where the altitude is high, temperatures are moderate and evaporation rate is low. In the Eastern part of the district, which forms the Kerio Valley and where the altitude is low, low rainfall, high temperatures and high evaporation rates 
Volume 2, September 2013 Issue 

characterize the climate. In between these two extremes, there are variations as one drop from the highlands to the floor of Kerio Valley. The mean monthly temperatures vary between 17° C and 22° C. It is generally hot in the valley, while 
it is cold in the highlands, mainly in Nyaru and Iten. The rainfall pattern is bi-modal in nature with long rains from March to June and short rains occurring between June and December, though it varies from one area to another within the district. The Keno Valley has been formed by several phases of intensive volcanic activities. Most of the extensive rocks include basalts, phonolite, trachylespyroclassic rocks and alluvial deposits. The rock formations in the county can be divided into basement systems (metamorphic), tertiary volcanic (extensive igneous) and quaternary alluvial deposits (sediments). Most of the coarse debris in these sediments is basement material derived from the escarpment. The sediments occur throughout the Kerio Valley. They consist of red and brown silts with numerous irregular coarse debris. Extensive igneous rocks are mainly found in southern part of the district. Soils in the district vary with location and altitude (Pratt and Gwyne, 1977). RNGRCA has a variety of vegetation and habitat types that can be explained by the difference in altitude and the varying climatic conditions. Its virgin wilderness is covered by a vibrant biotic community, which consist of thorn bush and woodland. The vegetation is dominated by Acacia trees (mostly A. mellifera and A. tortilis), bush lands and cactus, plus other prickly leaved species. Within the Reserve, the biotic communities are basically arid thorn bushland and woodland. Grasses in the Reserve are dominated by Themeda triandra and Cynodon dactylon in the open glades. The vegetation is green and thick during wet seasons but becomes scorched brown and sparse during dry periods. Vegetation progresses gradually from open glades of grassland and scrubland along the Kerio River through open bush lands to thick bushes and forests of Acacias and Balanites aegyptica. The vegetation and habitat of RNGRCA can be categorized into forest, woodland, bushland and grassland (Board of tourism, 2007). 
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Volume 2, September 2013 Issue 

Figure 1.1: Regional setting ofRimoi National Game Reserve and conservation area 
The fauna are composed of the elephants (Loxodonta a/ricana), Waterbucks (Kobus ellipsiprymnus), Bushbucks (Tragelaphus scriptus), Blue monkeys(Cercopithecus mitis), Dik diks(Rhynchotragus guentheri), Bushpigs (Potamochoerus porcus), Warthogs(Phacochoerus aethiopicus),Baboor.s (Papio anubis), Impala (Aepyceros melapus) and the African hare (Lepus capensis). The birds include pigeons (Columba guinea). Weavers (Bubaloruis niger), Ibis (Threskiornis aethiopcll) to mention a few (Board of tourism. 2007). 
Materials and Methods 
The data on preferred forages by elephants were 
obtained by making a systematic record of the feeding behaviour. Their diet was deduced from records of plants which showed obvious signs of recent elephant use. The vegetation browsed was identified during the early hour visit in the study area (7.00 am). The plants that were browsed on by the elephants were recorded. the plant species identified and picked. The plants showing signs of browsing were taken to be the sampling 
stations for plant samples along the feeding trails. After identification of the plants, the leaves, branches and bark of the foraged plants were collected. The samples were air dried, packed in brown paper bags and taken immediately to the laboratory for further analysis. The collected data were coded in Statistical Package for Social Sc\ences (SPSS ver. 17.0) and analyzed by descriptive methods. 
Results 
Preference of the wild vegetation by 1. a/ricana 
is provided in Figure 1.2. The five most preferred wild forage were Acacia tortilis (22.5%) followed by Balanites aegyptica (14.8%), then Acacia mellifera (9.6%) and Zizyphus mucronata (7.5%) and Acacia brevispica (7.1 %). The other components of ~e elephant diet in this region were: AcaCia hamu/osa, Acacia abyssinica, Compreturn sfP' and Grewia bicolor. However, observatIon during the field study showed that. both t~e leaves and bark of the Ficus 5pP· and AcaCia tortilis were consumed by the L. africana. 

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. Journal o/Technology & Socio-Economic Development 
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. Volume 2, September 20131ssue 

Figure 1.2: Wild vegetation preference by Loxodonta africana in Rimoi Conservation Area based on the estimates from counts along the feeding trails 
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Figure 1.3: Crop preference by Loxodonta africana in areas adjacent to Rimoi Conservation Area based on Likert scores from data on the questionnaires 

The preference of crop raiding of the domesticated crops by the African Elephant is shown in the Figure 1.3. There were significant differences in the crop raiding patterns of the crops ('l = 36.443, df'= 5, P = 0.0003). Based on the findings, the most preferred crops and therefore most raided was maize (86.5%) followed by millet (51.4%) and green grams (34.8%), while the least raided crops were cowpea (16.8%) followed by millet (7.3%). 
Discussion 

This study showed that elephants consume different plant species with varying degree of preference. Large herbivores are opportunistic grazerslbrowsers so their diets vary greatly from 
Cowpea 
Groundnut 
place to place, time to time, and among individuals and species. The daily diets of African elephants in Rimoi conservation area were selected entirely from the indigenous vegetation which does concur with findings of Holdo (2003); SmaIlie and O'Connor (2000). Nineteen wild plant species viz., Acacia tortilis, Balanites aegyptica, Acaia mellifera, Zizyphus mucronata, Acacia brevis pica, Acacia hamu/osa, Acacia abyssinica, Combretum spp., Grewia bicolor, Cissus rotundifolia, Cynodon dacty/on, Eragrostis minor, Achyranthes aspera; Sanseviera intermedia, Sarcostemma vimina/e, Grewia mollis, Chloris pycnothrix, Ficus spp. and Aloe spp. were used in different ways by elephants as food in this region. The selected species were not used in a similar manner, as 
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Journal of TechnoJogy & Socio - Economic Development 

shown by the study; some were browsed more often and debarked at the same time. Unlike findings of Varma et al., (2008) which sho ved elephant diet to be dominated by grass, results of this study showed that elephants in Rimoi National Game Reserve preferred Acacia plants (51.5%) more than any other. They consumed both the stems, leaves and barks, which do concur with the findings of Varma et al., (2008) where he indicated that Elephants did not exclusively consume the leaves of any plant but these were consumed along with the stem, shoot or fruits. Others were only chewed (Sarcostemma viminale, Sanseviera intermedia) and the sap swallowed, while the fibrous part was not ingested indicating some particular nutrient were extracted from it. They consumed the leaves, twigs, floral parts, branches and occasionally the bark. Elephant feeding trails provided signs and an estimate of the elephants diet preference in Rimoi conservation area, which do concur with the way or determination by Chiyo et al (2005}; Theuerkauf et al., (2000) and Kabigumila (1993), where they used signs of elephant feeding to determine elephant diet preference and quality. 
However, determination of diet from feeding trails may be biased towards stems and leaves, and biased against foraging of food items that leave little evidence, such as fruit fall consumption (Rode et al., 2006). Because the size of the food items consumed by elephants could not be determined fully and included in the study, the results may not reflect the full food items preferred and consumption by elephants in Rimoi conservation area, but gives an indication. The results as earlier stated show that the use of the plant species is more skewed towards the acacia plants and is likely to affect the normal functioning of the ecosystem which do concur with findings of Pamo and Tchamba (2001), which indicate that elephants are implicated with vegetation change in structure and composition through their varied seasonal choice of food items that include felling and debarking in the dry season. 
Observations made in this study show that foraging behaviour of elephants are expected to bring about dramatic changes in vegetation due to the increased killing of woody vegetation, suppressed recruitment and regeneration of vegetation coupled with anthropogenic factors due to human population increase. From the results it is most likely that the preferred or more palatable species of vegetation will be exterminated by elephants as their population 

Volume 2, September 2013 Issue 
increase and the demand of food goes up, and may switch to new food items so as to continue their survival especially the cows (elephants in milk) which normally forage diversely on vegetation due to the demand in nutrients for milk synthesis to feed the calves. The study therefore found out that African elephants select food components from a wide spectrum of plants with varying degrees of preference. The selected plant species were not used in a similar manner; some were browsed more often, while others were debarked at the same time. It is therefore important that elephant populations should be closely monitored so as to translocate when carrying capacity of the environment is shown to be surpassed. Like in Rimoi conservation area migratory corridors of the elephants have been blocked by human habitation, especially to south Turkana and to Mau forest ecosystem. 
Acknowledgement 
The author acknowledges the participants in this paper and the Department of environmental Biology in their contribution to the success of these researches. 
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