BINDURA UNIVERSITY OF SCIENCE EDUCATION FACULTY OF AGRICULTURE AND ENVIROMENTAL SCIENCE
DISSERTATION: The feeding selectivity of eland (Tragelaphus oryx oryx) in Chivero Recreational Park.
NAME CHIKOMBORERO CARLTON KASAWAYA
STUDENT ID B1025739
A FINAL WORK RELATED LEARNING PROJECT DESSERTATION TO BE SUBMITED TO THE FACULTY OF AGRICULTURE AND ENVIRONMENTAL IN PARTIAL FULFILMENT OF THE BACHELOR OF SCIENCE ENVIRONMENTAL DEGREE IN WILDLIFE AND RANGELAND MANAGEMENT AT BINDURA UNIVERSITY OF SCIENCE EDUCATION .
DEDICATION
This thesis is dedicated to the furtherance of conservation and my parents.
ACKNOWLEDGEMENTS
I would like to express my profound gratitude to my supervisors Mr. J Muvengwi and Miss Mbiba. Special mention goes to my father and mother for all the moral support. I register my indetness to my workmates and friends for their support and assistance in several ways during the course of the project. Special mention and gratitude goes to Mr. Makumbe and Mr. Chikorowondo for their assistance in data analysis.
Appreciation goes to the acting Director General (ZPWMA), Mr. Chidzeya for affording me an opportunity to be attached with the ZPWMA. I would like to register my appreciation to my on the job supervisors that is the Officer In Charge Mr. Sibanda, field supervisor Senior Ranger (finance and Admin legal and co operate services) Mr. Dzika, the Area Manager (Mr. Mhosira), Senior Wildlife Officer (Mr. Mapiki) and the Rangers for their passionate support to my academic and personal welfare during the attachment period, their mentoring during my placement period and their relevant input for the fruitful completion of this report.
I would also like to induce my appreciation with the department of Environmental Science from Bindura University of Science Education for without your support this project would be of no essence.
ABSTRACT
The eland is the largest antelope, a flagship species in Chivero’s ecotourism. Its conservation is therefore important for ecotourism and biodiversity at large. The natural diet of wild animals has a significant effect on the growth, the successful recruitment of viable offspring in animal populations and biologically fit antelopes. The study sought to investigate investigated seasonal variation in the selective utilization and dietary contribution of grass and woody plant species, parts, and height classes to vegetation consumed by elands, the feed preference index and to compare eland dietary diversity and species diversity between wet and dry season in Chivero Recreational Park Zimbabwe. A total of plots 60 circular of 1m radius were sampled randomly along feeding trail 2m wide, 30 per seasons. Dung samples were also collected between seasons and 8 elements (Na, Mg, Ca, S, P, N, K and Fe) were lab tested for nutritive concentrations. Diet contribution was analysed, results indicated significant difference between dry and wet seasons with (P < 0.001). Feed preference index was significantly different between dry and wet season with (P = 0,033). Diversity was very highly significantly different between dietary diversity and ecosystem diversity with (P < 0.001). Only 17% of the commonly fed woody species contributed 90% of the diet increasing to 93% in the wet season and 19% of the commonly fed grasses contributed 43% increasing to 72% in the wet season. Six grass and eleven woody species remained very lowly and moderately accepted by the eland. Most of the preferred browse consumed during each season came from 1 or 2 common shrub species. Leaves and leaf bearing shoots constituted 80% of the material consumed from woody plants during the dry season. Stems and leaves of grasses constituted 77% in the dry decreasing to 68% in wet season. On faecal samples collected only sulphur differed significantly between seasons, increasing highly in the wet season. The results indicate seasonal variation within the species that support eland diet. Eland dietary diversity was lower than ecosystem diversity in both seasons contrary to most studies. Most of the species that constitute eland diet are absent in Chivero hence there was adequate evidence on fire effect in the sour veld.
Key words: Acceptance, availability, Chivero dietary diversity, eland, faecal, flagship, feed preference index and feeding trail.
Table of Contents CHAPTER I ...... 11 INTRODUCTION ...... 11 1.1 BACKGROUND...... 11 1.2PROBLEM STATEMENT ...... 12 1.3 JUSTIFICATION ...... 12 1.4 Aim ...... 13 1.5 Objectives ...... 13 1.5 Hypotheses ...... 13 CHAPTER II ...... 14 LITERATURE REVIEW ...... 14 2.1ELAND ECOLOGY ...... 14 2.1.2 ELAND GENUS AND DISTRIBUTION ...... 15 2.2 Eland Description ...... 15 2.3 Eland Principal or Primary feed ...... 16 2.3.1 Determination of principal or primary feed ...... 16 2.4 Accepted or Preference Feed ...... 16 2.4.1 Determination of feed preference ...... 17 2.5 Eland Ecology and Habitat Use ...... 17 2.6 Ecology of other competitors ...... 18 2.7 Preferred feed of the Eland ...... 19 2.7.1 Significance of feed preference ratings ...... 20 2.7.2 Seasonal Variation of Feed ...... 21 2.8 Feed Availability ...... 21 2.8.1 Effects of inadequate feed ...... 22 2.8.2 Eland favourite habitat ...... 23 2.8.3 Eland wet and dry season Home ranges ...... 25 2.8.4 Factors affecting habitat selection by ungulates ...... 26 2.8.6 Significance of suitable habitat to animal populations ...... 26 CHAPTER III ...... 27 MATERIALS AND METHOD ...... 27 3.1 DESCRIPTION OF THE STUDY AREA ...... 27 3.2 THE PHYSICAL ENVIRONMENT OF CRP ...... 27 3.3 THE BIOTIC ENVIRONMENT OF CRP ...... 28 3.3.1 Wildlife Species ...... 28 3.3.2 Vegetation ...... 29 3.4 Vegetation and plant inventory ...... 29 3.5 SAMPLING PROCEDURE ...... 29 3.6 MEASURED/RECORDED VARIABLES AND MEASUREMENT TECHNIQUES ...... 29 3.7.1 Availability ...... 30 3.7.2 Acceptance ...... 30 3.7.3 Feed preference index ...... 31 3.7.4 Diet contribution ...... 31 3.8 DATA ANALYSIS ...... 31 3.8.1 Acceptance and Availability Analysis ...... 31 3.8.2 Diet contribution Analysis ...... Error! Bookmark not defined. CHAPTER IV ...... 33 RESULTS ...... 33 4.1 INTRODUCTION ...... 33 4.2 Diet Contribution within Dry Season ...... 33 4.2.1 Diet Contribution within Wet season ...... 33 4.2.3 Dietary Contribution between Dry and Wet Seasons ...... 34 4.3 Feed preference Index within Dry season ...... 34 4.3.1 Feed preference index within wet season ...... 34 4.3.2 Feed Preference between Dry and Wet seasons ...... 35 4.4 Faecal Samples ...... 38 4.4.1 ACCEPTANCE AND AVAILABILITY CORRELATION IN SEASON ...... 39 4.5 Dietary Diversity ...... 39 4.1 Wet Season Feed Preference ...... 40 4.2 Wet Season Principal/primary Feed ...... 40 4.3 Dry Season Feed Preference ...... 40 4.4 Dry Season Principal/primary Feed ...... 41 4.5 Seasonal Variation on Principal/primary and Preferred Feed Species ...... 41 CHAPTER V ...... 42 DISCUSSION ...... 42 5.1 DIET COTRIBUTIONS ...... 42 5.1.2 Diet contributions within Dry Season ...... 42 5.1.3 Diet contribution within Wet Season ...... 42 5.1.4 Diet contributions between Wet and Dry Season ...... 42 5.2 Plant species selection ...... 43 5.2.1 Feed preference Index and acceptance within the Dry season ...... 44 5.2.2 Feed preference Index and acceptance within the Wet season ...... 44 5.2.3 Feed preference Index and acceptance between Dry and Wet Season ...... 44 5.3 Shannon Weiner Diversity indices ...... 46 5.4 Pearson correlations ...... 47 5.5 Competition with other species ...... 47 5.6 Eland distribution influenced by feed ...... 47 CHAPTER VI ...... 49 CONLUSION AND RECOMMENDATIONS ...... 49 6.1 Conclusion ...... 49 6.2 Recommendations ...... 49 REFERENCES ...... 51 Appendix A: dry season diet contribution ...... 56 Appendix B wet season diet contribution ...... 56 Appendix C. Mann Whitney U test and Wilcoxon W ...... 58 Appendix D. Tables showing calculated Diet contribution ...... 59 Appendix E. showing browsed heights ...... 60
List of tables
Table 3.0 Measured/recorded variables and measurement techniques ………………………27 Table 4.0: Patch Based Eland faecal samples in Chivero……………………………………36 Table 4.1: Pearson Correlation between Available grass species and those accepted by an eland when accepted within its home range in Chivero ………………………………...... 38 Table 4.2: Feed Preference Ratings of different woody and herbaceous plants in CRP……39
List of figures
Fig 2.0 Eland distributions in Africa …………………………………………………………12 Fig 2.1 Eland Source Range map: (Redrawn, IEA 2008)……………………………………12 Fig 3.0 Location of the study are a……………………………………………………………25 Fig 4.0 Dietary contribution of grass species constituting eland diet during the dry season ………………………………………………………………………………………... 31 Fig 4.1 Dietary contribution of grass species constituting in the eland diet during the wet season ……………………………………………………………………………………….. 32 Fig 4.2 Feed preference Index box plots of grass species constituting the eland diet during the dry and wet season in Chivero ………………………………………………………………33 Fig 4.3 Patch based acceptance frequency versus availability for 9 grass species with adequate samples ……………………………………………………………………………34 Fig 4.4 Patch based acceptance frequency versus availability for 11 woody plant species with adequate samples ……………………………………………………………………………35 Fig 4.5 Shannon Weiner Dietary diversity Index mean graph of grass species constituting the eland diet between the dry and wet season in Chivero ……………………………………... 38
List of Acronyms CITES: Convention on International Trade of Endangered species. CPA: Chivero recreational park. IEA: International Environmental agency. IUCN: International union for conservation of Nature. UZ: University of Zimbabwe. ZPWMA: Zimbabwe parks and Wildlife Management authority.
CHAPTER I
INTRODUCTION
1.1 BACKGROUND. Herbivore populations are influenced by a combination of food availability and predator pressure, the relative contribution of which is hypothesized to vary across a productivity gradient, rainfall and altitude (Richards et al., 2006). The grasses selected by herbivores vary in their retention of greenness and their utilisation varies between the dry and wet seasons with some extensively grazed by the mid dry season evidently through re grazing of tufts (Knoop, 2006a and Owen Smith, 2006b). Food quantity, rather than quality appears to attract browsers to foraging sites in the late wet and early dry seasons. Food quality seems to be more important in the early wet and late dry seasons (Heitkoning et al., 1998). Forage selection has been observed to be influenced by edaphic factors which determine the distribution of palatable and unpalatable herbaceous and woody plant species (Fleming & Loveridge 2003, Holdo & McDowell 2004, Pretorius et al., 2011). In Zimbabwe, Chivero is such a veld in natural region 3 which receives considerable amount of rainfall annually but is however a sour veld. This may influence distinct herbivory pattern by the eland.
The study focuses is on determination of plant species selection by the eland, diet contribution of different woody and herbaceous species to the eland diet and compare eland dietary diversity and ecosystem diversity. Studies have shown seasonal differences in feed preferences of eland and roan antelope, hippotragus equinus , to vary between seasons. Recent studies have shown distinct herbivore feeding behaviour to vary in relation to soil cartina bottomland and upland by antelopes (Knoop and Owen Smith, 2006), in relation to grazing pressure. Vegetation growing in nutrient poor environments has been demonstrated to have high concentrations of secondary compounds which influence feed palatability and selection (Coley et al., 1985, Owen Smith 1993, Owen Smith & Cooper 1987a). Vegetation on termitaria may not act as nutrient hotspots for elephants (Muvengwi et al., 2013), the same vegetation in utilisable heights to antelopes also act as their browse. In pursuit of this study, investigation on the dietary niche of the eland is at the core its uniqueness. Based on rumen anatomy, eland ( Tragelaphus oryx, Pallas) have been classified as intermediate feeders preferring browse (Hofmann & Stewart, 1972; Hofmann,1973). Most field studies support this classification (e.g. Kerr , Wilson & Roth, 1970; Jankowitz, 1982; Buys, 1990), while in others eland were found to be predominantly grazers (Lamprey, 1963; Underwood, 1975; Nge’the & Box, 1976). In all studies, where the contribution of forbs to the diet was assessed, such herbaceous browse formed an appreciable percentage of the diet (e.g. Kerr et al. , 1970; Field, 1975; Jankowitz, 1982).
1.2PROBLEM STATEMENT Eland ( Tragelaphus oryx oryx ) numbers have progressively declined in parts of Southern Africa, according to (Grant et al., 2002, Owen Smith and Ogutu, 2003). The eland population at Chivero South Bank Recreational Park has dramatically and progressively declined from approximately 100 individuals to approximately 20 individuals distributed in the eastern part of the park in about 5 years (PWMA, 2010). There might be many causes of the population decline, but it is assumed that feed availability could be the cause especially in the absence of predators. Frequent intense veld fires could have affected vegetation dramatically. It is also suspected that veld fires that followed scheduled block burning reduced complex communities to simple ones following poor resilience by herbaceous plants (PMWA, 2012).
1.3 JUSTIFICATION Eland have been recorded on a wide variety of vegetation types, including montane grassland, savanna and but no studies have examined the diet composition and selectivity of eland in sour tall hyparrhenia grass veld like Chivero. This represents a gap in the understanding of eland feeding ecology, especially since modelling (Owen Smith, 1985) has indicated that eland should favour vegetation types offering high abundances of browse species with high leaf: stem ratios. The natural diet of wild animals has a significant effect on the growth and the successful recruitment of young individuals in animal populations (Bothma, 2002). The composition of diets selected by wild and domestic ungulates has long been of interest to range and wildlife. In optimal foraging Hanley, (1982) the animal must be able to keep track of the constantly changing browse and adjust their functions of differing phenologies and habitats. The foraging ungulate must detect the values of individual browse species while consuming continuous multi species meals. Knowledge of the reasons why ungulates select on feeds is necessary for an understanding of the forage needs of animals and the underlying basis of competitive interactions among species (Pyke et al., 1977). However visible signs of malnutrition and undernourished antelopes are present in the park with high mortality rates at natality stage. The research findings will help illuminate the dietary niche of elands from browsing ruminants and in turn reduce the chance of local extinction of the eland. Chivero is a great tourist attraction in ecotourism business and an eland one of their flagship species.
1.4 Aim To investigate eland feed selectivity between two seasons (wet and dry) in Chivero Recreational Park.
1.5 Objectives To determine the diet contribution of different woody and herbaceous species to eland diet in Chivero Recreational Park. To determine plant species selection by eland in Chivero Recreational Park. To compare eland dietary diversity and ecosystem diversity of their home range.
1.5 Hypotheses H1: The selected feed species by the eland in Chivero Recreational Park differs between wet and dry season.
H1: Eland diet selection is correlated with plant availability.
H1: Diet has a higher Shannon Weiner diversity than both available and eaten plant species.
CHAPTER II LITERATURE REVIEW
2.1 ELAND ECOLOGY
2.1.1 Eland Distribution in Africa
Figure 2.0: Eland distributions in Africa
Source: Range map (Redrawn from, IEA2008)
Figure 2.1 Eland
Source Range map: (Redrawn, IEA 2008) 2.1.2 ELAND GENUS AND DISTRIBUTION The eland (Tragelaphus oryx oryx ) of Botswana, Southern Zimbabwe and Namibia is one of the three sub species that are recognised in Southern Africa, the other two being the eland (Tragelaphus oryx livingstonii ) of Angola, Zambia, Zaire and Northern Zimbabwe and East Sudan, Kenya and Tanzania eland Tragelaphus oryx pattersonianus (Bothma, 2002). Estes(1991) states that, they are five well defined eland races: the Tragelaphus oryx oryx which has the largest geographical range in Sothern Africa, the pattersonianus occupying the coastal hinterland of Kenya and Tanzania has the smallest horns perhaps confined to the Shimba hills national Reserve. Giant elands Tragelaphus derbianus giggas, Tragelaphus derbianus derbianus , so called because the giant eland has horns averaging about four foot longer and weighs 25 50kilograms than other races, and it occurs in Northern Savannah regions. The most distinctive race is Tragelaphus derbianus giggas , the “Lord Derby’s” eland found northern savannah have bluish greyish colour in aging adults. The eland was originally classed in a separate genus Taurotragus , but recently re placed in the genus Tragelaphus based upon evidence of hybridization with the greater kudu Tragelaphus strepsiceros and the sitatunga T. speckii, together with mitochondrial DNA studies and allozyme analysis.
Three oryx species were critically endangered this decade. Nine of eighteen antelope species across three tribes are considered endangered by the IUCN. The common eland's population is decreasing, but it is classified as "Least Concern" by the International Union for Conservation of Nature (IUCN).Some species have even been extinct in the wild and have since been reintroduced such as the Arabian oryx ( Leucoryx oryx ). Other species that are endangered include the eastern bongo ( Tragelaphus eurycerus ), mountain nyala ( Tragelaphus angasii ) and western giant eland (Tregalaphus derbianus).
2.2 Eland Description The eland, Tragelaphus oryx oryx is a large ox like animal, heavily built with relative thick legs. Adult males are 30 35% heavier than females and easily recognised at a distance. The forequarters are notably larger and heavier than the hind and as a result, the front feet are larger. The most representative form is the southern Cape eland which are tan coloured, dull fawn, without body stripes and a dark brown mark down the back of the forelegs above the knees. In northern Botswana, Zimbabwe and southern Mozambique, hybrids and crossbreeds between the southern Cape and Livingstone’s eland have between 1 5 vertical body stripes. Livingstone’s eland have 6 7 vertical white stripes 9 12 mm wide on the flanks but lack the prominent, dark brown marking on the forelegs. East African eland are a rufous fawn with 8 12 narrow stripes 4 8 mm wide down the flank and a white chevron above the eyes on the forehead. Hybrids of the southern Cape eland and the east African eland which have the same rufous colouring but are without stripes are common where distributions overlap. Lord Derby’s eland have a rich terracotta, reddish brown to chestnut colour with 8 12 narrow stripes, a distinct dark brown to black blaze around the bottom half of the neck and a short black mane stretching down the neck to the middle of the back. Aging adults tend to lose their hair resulting in the overall colour becoming bluish grey due to the skin reflecting through the coat. A large dewlap descends from the throat of adult bulls. The dewlap of Lord Derby’s eland is longer and starts from the chin.
2.3 Eland Principal or Primary feed A principal feed species can be defined as the feed species the animal eats in greatest quantities. This disregards its relative availability, calorific or other nutritive values (Short and Smith, 1994). A principal feed, on the other hand, is one that makes up a large proportion of the animal’s intake, irrespective of its preference relative to other feed on offer (Tainton, 1999).
2.3.1 Determination of principal or primary feed Principal feed are often, therefore, determined by circumstance. If, for example, an animal is presented with forage from only a single species then, assuming that it is prepared to consume that feed that species will automatically serve as the principal feed species (Tainton, 1999). In a mixed sward, the principal feed is a function of the number of species and the relative acceptability and abundance (equitability) of each (Tainton, 1999).
2.4 Accepted or Preference Feed Preferred feed are those, which are proportionately more frequent in the diet than in the available environment (Petrides, 1975). Feed preference is the extent to which feed is consumed in relation to its availability (Petrides, 1975). Preference is shown by an animal when it consumes a particular feed in larger proportions than that in which it is presented to that animal (Mentis, 1981b as cited in Tainton, 1999), irrespective of the extent to which that feed contributes to the total diet of that animal. Practically every study that has been made of the feed habits or ecology of a particular species of animal has shown that certain feed are taken in greater abundance than other feed that are available in equal quantities, (Dice, 1952). Most antelope’s exhibit feed preferences. The feed preferences of antelopes may be correlated with the nutritive values of their feed, but this is not always true. The concept of feed preference has a widespread ecological significance. It is basic to scientific range management, to the understanding of predator prey relationships and to other aspects of animal biology (Petrides, 1975). The feed preference measures the Like ability of forage species. The concept of preference also can be used to evaluate habitat (Sampson, 1952
2.4.1 Determination of feed preference Stoddart and Smith (1955), states that one thing which determines the use factor is how well animals like the particular species. This is referred to as preference. Preference is determined by the choice an animal makes if given free access to various plant species. For example, a hungry animal might be forced to eat as much wheat straw as alfalfa hay, but if both were placed before him, he would choose the alfalfa hay and therefore its preference rating would be higher. Petrides(1975) states that to determine feed preference relationship in the field, it is necessary to measure the amount of various feed available (A) for feeding and the extent to which those feed are actually removed (R) by herbivores. Attempts to develop preference ratings for the several feed eaten in nature by a particular kind of animal have been made by a number of investigators (Dice, 1952). Each preference rating should be based upon the proportions of the several kinds of feed actually consumed by the animals. The preference rating for each feed species necessarily varies more or less with the season and with age of the consumed individuals (Dice, 1952). Furthermore, any measure of the feed preference of a given kind of animal actually applies only to the particular area and to the particular conditions for which it is calculated. Preference ratings will be critical in studies, but for many ecological investigations a simple classification will suffice (Dice, 1952). It is suggested that a classification of feed preference that include only four categories of highly preferred, moderately eaten, slightly eaten, and refused will often be adequate (Dice, 1952).
2.5 Eland Ecology and Habitat Use Eland are gregarious, medium sized grazers with an average body mass of 942kg (Estes, 1997). A herd of about 15 30 individuals composed mostly of females, calves, sub adults (Estes and Estes, 1974; Estes, 1997). Eland herds are cohesive and are maintained through having a stable social structure (Estes and Estes, 1974; Sekulic, 1981). Males are territorial and defend their territories from other males. Eland habits include the following landscape level vegetation associations: forests (Sekulic, 1981), open woodlands, xerocline slopes, vleis, and grasslands with medium tall grasses (Ben Shahar and Skinner, 1988; Magome et al., 2008; Parinni, 2006). The most important factors that influence the feeding behaviour of animals are the availability and acceptability of, their preference for, and the digestibility and chemical composition of their feed (Bothma, 2002). The eland favours a mosaic arrangement of woodland and grassland (Estes, 1991). The woods have to be open enough to support an under story of grasses, which are utilized in the rainy season. Eland herds range the open grassland in the dry season in search of green plants, including the forbs and foliage that make up C.20% of their diet (Estes, 1991). Termite mounds, which support lusher growth than the surrounding leached ancient soil, have many of the grasses and browse plants they like best. Dry season movements depend on the availability of water and feed. Forage quality is in turn closely dependent on annual, manmade fires that burn off the tall dead grasses within a month or two after the rain ends (Estes, 1991). Green flush comes up along the drainage lines with their heavier clay soils while the doughtier woodland soils remain blackened and lifeless until woody plants put out new leaves in the Miombo spring, a good month before the rains begin attracting the Eland back to the woods. Eland regularly visit salt licks, typically situated at the bases of termite mounds, and where soils are particularly poor, they may visit the sites of old kills to chew bones presumably to acquire calcium and phosphorous (Estes, 1991).
2.6 Ecology of other competitors Eland are sensitive to drought and to competition by other animals(Bothma, 2002).Estes (1991) states that elands, like the Roan is associated with the Brachystegia/Isoberlinia wooded savannah, but is less of woodland and more of grassland/tree savanna species, tolerating taller grass and higher elevation including mountain grasslands such as Malawi’s Nyika plateau and Zimbabwe Chimanimani Mountains. Also like the Eland, Roan antelope is a selective grazer on perennial grasses that grow in leached soils of poor nutrient status which support a low herbivore biomass, offering little nourishment in the dry season except on low sground that retains enough moisture to produce growth after annual fires (Estes, 1991). The Roan just like the elands browse to some extent (up to 10 20% of rumen contents) on forbs leaves and pods. Like other water dependent wildlife, the Roan and the Eland concentrates near water points during the dry season and disperses during the rains (Estes, 1991). A high crude protein and low fibre diet is important, much the same as for the reedbuck (Bothma, 2002).The Roan tends to be late risers like the eland, especially on cool mornings when the grass is soaked with dew. In Kenya’s Shimba Hills Reserve, a trans located Roan herd observed between July and September, lagged about an hour behind the indigenous eland, often resting until 0900h, then grazing intensively between 1000h and 1100h, with a resting peak from 1400h to 1500h. Both species had feeding peaks in the last hours of daylight and settled to rest and ruminate after dark ‘author’s observation’ (Grobler, 1974) as cited in Skinner and Smithers, 1990).
2.7 Preferred feed of the Eland Grobler(1974) as cited in Skinner and Smithers (1990) states that in Zimbabwe 23 species of grasses were recorded as preferred by the eland. These include among others the Buffalo grass, Panicum maximum ; Spear grass, Heteropogon contortus ; Eragrostis jeffreysii ; Red grass, Themeda triandra and Urochloa oligotricha were recorded as being utilized on a year round basis. Wilson (1969) and Estes and Estes (1974) both added to the list of species utilized in this area. Wilson (1975) as cited in Skinner and Smithers (1990) states that in the Northern Transvaal, Elands showed a marked preference for black footed brachiaria, Brachiaria nigropedata, and would also heavily utilize red grass, Themeda triandra ; Spear grass, Heteropogon contortus ; Yellow thatch grass , Hyperthelia dissolute ; Thatch grass, Hyparrhenia hirta ; Slit grass, Schizachyrium jeffreysii ; and Gum grass, Eragrostis gummiflua . In this sector browse was utilized to a very limited extent. Grass species consumed by Eland include Eragrostis superba , Chrysopogon species and Andropogon species among others (Grobler, 1981; Wilson and Hirst, 1977; Ben Shahar and Skinner, 1988). Most of these grass species grow in areas with low woody cover where they may have less competition for sunlight, water and nutrients (Medina and Silva, 1990; Pellew, 1983). Shade tolerant grass species like Panicum maximum are frequently eaten by Eland, partially due to their high nutritional value and moisture content (Parinni, 2006). In Zimbabwe, Wilson (1969a) as cited in Skinner and Smithers (1990), included among browse plants utilized Sweet thorn, Acacia karroo ; Lippia oatzii ; Rhus lancea ; Silver raisin bush, Grewia monticola , and the fruits and leaves of sickle bush, Dichrostachys glomerata , and the fruits of Buffalo thorn, Ziziphus mucroanata . Grobler (1974) as cited in Skinner and Smithers (1990) added Wild pear, Dombeya rotundifolia ; Raisin bush, Grewia flava ; Fever tea, Lippia javanica , and Wild camphor bush, Tarchonanthus comphoratus , to the list of browse plants noting that the last named is an important species prior to the rains. Kingdon (1997) states that, eland prefer new grass growth or grasses of medium height belonging to locally dominant species. Estes (1993) states that elands are (grazers/browsers) mixed feeders, eats grasses supplemented by foliage and herbs, especially kinds growing on woodland termite mounds. The eland is considered a browser, preferring leaves and shrubs, since grass is not the major component of the diet (Abdullahi, 1981; Codron et al., 2007). They are found mainly in lightly forested areas as well as grass lands of southern Africa. The terrain utilized is plain and savannah of southern and eastern Africa. They may graze on grasses but the basis of the diet is achieved from browsing brush, shrubs, and low trees (Buys, 1990). They exhibit crepuscular behaviour, feeding in the early morning and late evening, when temperatures are cooler (Lewis, 1978). Elands do not maintain territories as other antelope species; however, they do maintain a herd hierarchy (Underwood, 1981; Wirtu et al., 2004). They roam large distances to keep up their foraging habits. Eland can be found in herds of 25 to 60, but herds containing up to 100 have been observed. From observations, females reach sexual maturity around 2.5 years of age while males reach sexual maturity at 4 years of age (Hall, 1975; Hosking and Withers, 1996).
The degree of selectivity that can be exercised by a large herbivore, within its time energy constraints, is determined largely by mouth size. Animals with small mouths are more capable of being selective of plant parts than animals with large mouths are (Meyer et al., 1957, McClymont 1967, Jarman 1974). The ability to forage selectively (determined by the time energy constraints and mouth size) is very important when browse is being eaten. Whereas leaves and current annual growth of browse species may be about 65% cell solubles and 10% lignin, older twigs may be only 30% cell soluble and 20% lignin (Blair et al., 1977). The ability to harvest selectively the leaves and current annual growth without also harvesting the older twigs therefore is important in determining the relative value of browse forage to an herbivore. Such ability has been mentioned frequently for small mouthed ruminants such as sheep, pronghorn, and deer (Cook and Harris et al., 1950), but seldom mentioned for large mouthed ungulates such as cattle or horses. Rather, cattle do not appear to be capable of such a fine degree of selectivity, as evidenced by their browsing effects on the growth form of antelope bitterbrush (Hormay 1943).
2.7.1 Significance of feed preference ratings Feed preference ratings provide useful evidence towards the understanding of trophic ecology and practical resource management (Cook and Stoddart, 1953). They yield information on the sustainability of ranges as animal habitats and enable appraisals of the abundance of consumer organisms with respect to range carrying capacity. The relative abundance and condition of feed species present in an area may further indicate the vigour of consumer populations and whether feed limits consumer abundance there.(Gandiwa et al., 2006) If calculated similarly on a widespread basis, preference values should enable meaningful comparisons between research appraisals and management results across the geographic ranges of important species (Cook and Stoddart, 1953).
2.7.2 Seasonal Variation of Feed The diet of many kinds of animals varies considerably from season to season and often from year to year (Dice, 1952). This is due to variations in feed preferences and in requirements at successive life history stages, at successive ages, and at various seasons, but is especially governed by variations in the kinds of feed available (Dice, 1952). The California quail, for example, feed principally on green vegetation in the winter and spring, but in summer and fall, when its feed plants usually dried up, it feed for the most parts on seeds (Dice, 1952). Only a relative few kinds of animals subsist on a single kind of feed which is available at all times in sufficient quantity for their needs. Any precise consideration of the feed relations with an ecosystem must include a measurement of the kinds and amounts of feed which are present at each season (Dice, 1952). Special attention must be given to the fluctuations in the kinds and amounts of feed available. The preference ratings for each feed species necessarily vary more or less with the season and with the ages of the consumed individual. Animals may or not change their preference and principal feed with the change of the season. They may or not also change on their preferred plant part and height with the change of the season (Dice, 1952). The seasonal variations in community activity result in fluctuations not only in the amounts but also in the kinds of feed available to animals (Dice, 1952). In cold climates, for instance, the green, lush vegetation of summer gives place in winter to much more barren conditions. Grobler (1981) observed Eland using more open savannah woodlands during the dry season compared with the areas used during the wet season.
2.8 Feed Availability Feed is a fundamental requirement for all living organisms. It is not surprising that herbivores choose habitats in areas with abundant feed resources that can meet their body maintenance requirements (Senft et al., 1987). Some animal species secure feed and defend them from other animals thus establishing territories. When feed resources are abundant and uniformly distributed in space, most animals will not exhibit any form of selection and therefore aggressive behaviour is minimized (Houston et al., 1993). This ideal situation is not present in the nature as feed resources such as foraging grass are patchily distributed, while their abundance may be limited by environmental factors such as water and nutrient availability. Changes in feed abundance and quality directly affect grazing herbivores, which causes herbivores to change their behaviour to meet their feed requirements (Houston et al ., 1993). Any measure of the feed preference of a given species of animal based on digestive tract, Regurgitated pellet, or dung analysis must take into account the kinds and quantities of the various feed available to the animal (Dice, 1952). A kind of feed that is very abundant may be taken by an animal in greater quantity than another more preferred feed that is rare in the habitat. If all kinds of suitable feed are scarce, an animal may eat feed that usually would be refused (Dice, 1952). Also, some feed that are present in the habitat may be relatively inaccessible to a particular individual because they are outside his home range, are located in a position exposed to attack from predators, or are in place which the animal finds difficult to reach (Dice, 1952). The feed eaten by a given animal, therefore, are actually an indication of the kinds of feed available to him, as well as a measure of his feed preference (Dice, 1952). Most kinds of animals have at least a small degree of adaptability in their feed habits. If their preferred feed is not at hand, they are able to subsist on other less desirable feed types (Dice, 1952). The relative availability in the ecosystem of the various possible kinds of feed consequently has much to do with the quantities of each kind of feed consumed by a given species of animal (Houston et al ., 1993). Bothma (2002) propounds that not only the quality and quantity of the available feed are important for wild herbivores, but also the interaction between various species of herbivores when competing for the same feed resources. In terms of animal production, it is therefore not only the ability of the feed to supply energy, provided that sufficient protein, minerals and vitamins are consumed, but also the competition between the herbivores that is important (Bothma, 2002). In times of feed shortage, these differences tend to separate the herbivores in terms of feeding when competition for feed would be mutually harmful. Feeding height is also important. For example, the Sable and the Wildebeest feed at different heights when different grass species are available, but they will compete when the choice of graze is restricted (Bothma, 2002). Some herbivores also feed on the seed pods or leaves or different parts of plants.
2.8.1 Effects of inadequate feed Should the feed supply for a given species on a particular area be inadequate either in quantity or quality, the individuals of that species may be seriously injured (Dice, 1952). Inadequate of preference feed greatly affects the growth of young organisms usually results in stunting and population decline due to death (Farb, 1970). Sometimes the feed is adequate in quantity but may lack certain essential elements. This lack may affect the individual animals as seriously as a shortage of feed (Dice, 1952). Improper or insufficient feed may bring other ills than direct death through starvation. Emaciated and weakened animals become easy prey for carnivores. Starvation can be expected to reduce the rate of maturity and also the rate of reproduction thereby reducing the animal population and distribution (Ruthven, 1983).
2.8.2 Eland favourite habitat The density and distribution of different animal populations varies according to the abundance of their preferred habitat (Bothma, 2002). The eland preferred habitat combines, savannah woodland and grassland; trees (fire resistant, broad leafed, deciduous) widely spaced with understory of sparse grasses utilized in rainy season (Estes, 1993). Drainage line and floodplain grasslands that produce new growth after the annual fires keep the Elands in open during dry season (Estes, 1993). The Eland favours a mosaic arrangement of woodland and grassland (Estes, 1991). The woods have to be open to support an understory of grasses, which are utilized in the rainy season (Estes, 1991). Skinner and Smithers states that elands are savannah woodland species, dependent on cover and the availability of water. They prefer open woodland with adjacent vleis or grassland with medium to high stands of grass (Estes, 1993). Favourable habitat is a mixture of savannah woodlands and grassland. Woodlands consists of fire resistant, broadleaf deciduous trees scattered over an under story of sparse grasses that are grazed during the rainy season. Dry season feeding grounds are grassland areas that were once flooded, and then burned, subsequently producing new growth. If possible, tregalaphus oryx avoids extensive open lands (Estes, 1993). They avoid woodland where the tree density is high and areas where the grass is short, caused by over utilization or other causes. Bothma (2002) states that the eland is a rare and endangered eco tonal animal species that is highly selective in its choice of habitat. Its habitat requirements include plains with a dense medium to tall grass layer of good quality, a tree cover with a sparse lower shrub layer and a fairly dense canopy layer, sandy soils and water in close proximity. The grassland habitat of the eland is being reduced due to habitat destruction for agricultural development. Antelope are important to their habitats as grazers and browsers. They are also important as prey for carnivores. Eland live in savannah woodlands and grasslands during the dry season where they eat mid length grass and leaves. They are diurnal but are less active during the heat of the day (Wilson and Hirst, 1977). Eland form herds of ten to thirty females and calves led by a single male, called a bull. Wilson and Hirst (1977) compared woody canopy cover (tree cover) in areas occupied by eland in South Africa and Zimbabwe. They reported that total woody cover ranged between 8.9 24.9%, with tree canopy cover making a significant contribution. However, variability in cover estimates may be due to differences in vegetation communities but because eland habitat use is variable throughout the course of the year, hence it is difficult to generalize. Based on the optimal foraging theory, eland antelope are expected to choose open areas which allow them to maximize feed intake because of grass abundance but which may be of low quality due to increased steaminess. However, since forage of higher quality is associated with woody cover (Ludwing et al., 2008), and since elands are feed specialists (e.g., selecting high quality grass stems of Panicum maximum ); they are expected to straddle between the two cover types (intermediate cover). However, because eland occur at relatively low population densities, the predation avoidance hypothesis (Hirth, 1977) predicts that they should favour areas with more woody cover relative to surrounding areas. Eland herds in Kenya selected habitat on edges of forests with tall grass and sparse tree canopy cover (Sekulic, 1981). He further observed three factors influencing eland habitat choice: 1 grass height (eland showed preference for medium tall grass), 2 density of trees and bushes (eland preferred open areas with sparsely distributed trees and bushes), 3 plateau or hills (eland used mid slopes frequently). Eland herds did not use thick woodland areas and avoided upland slopes during the dry season (Sekulic, 1981). The avoidance of slopes and selection for valley habitat by eland in the dry season was ascribed to green leaf still available in valleys. Stevenson Hamilton (1974) indicated that eland preferred areas interspersed with thickets for shade and open valleys for grazing. Joubert (1974) documented a home range of 20 40 km2 for Eland in Kruger national Park (KNP) (Harrington et al ., 1999). The habitat preference parameters for Eland includes: abundant stands of dense, intermediate to tall grasses 45 150 cm high of both sweet and sour species open savannah woodland with scattered large trees and a lower stratum of moderately dense shrub land flat to slightly undulating topography well drained, sandy soil especially those derived from granite and quartzite clean surface drinking water for daily consumption (Stevenson Hamilton, 1974). Open grassy plains, short grass environments and thickets 23 are avoided, except for adult bulls taking refuge in thickets. Elands are extremely susceptible to droughts with a severe, rapid depletion of forage quality (Sekulic, 1981). These often result in high mortalities. As they are intolerant of severe cold spells, it is essential that the habitat includes patches of thicket vegetation that allow refuge against cold and winds (Sekulic, 1981). However, if not confined by a lack of space or game fencing, they may migrate away from these conditions. Elands are specialist grazers favouring environments with adequate feed quality and quantity, which may be characterised by the abundance of grass (Estes and Estes, 1974). Other habitat requirements for ungulates include water, adequate cover for protection from weather, and concealment cover from predators (Mangel and Clarke, 1986; Mysterud and Ostbyte, 1999), and for mating and rearing of young (Block and Brennan, 1993). The landscape configuration and density of woody plants is important as it affects aspects of animal ecology.
2.8.3 Eland wet and dry season Home ranges Eland have distinct wet season and dry season use areas (i.e., home ranges), although they may overlap, (Estes, 1974; Wilson and Hirst, 1977), each with its own woody cover characteristics. Harrington et al., (1999) also concluded that habitat selection by rare antelope was more evident in the late dry season where feed resource and water were limiting factors. Ogutu and Owen Smith (2005) suggested that drought mediated moisture loss in habitat adversely affected the nutritional content in elands diets and this reduces fitness levels. Grobler (1981) observed that the body condition of eland deteriorated during the late dry season when feed was limiting. During lean periods, elands spent more time feeding in open areas in the Matopos National Park, Zimbabwe (Grobler, 1981 Movements of Eland outside their home range into areas that have recently been burned to take advantage of new green flushes of feed have been documented (Magome, 1991, Sekulic, 1981). Eland showed seasonal habitat selection in Angola (Estes and Estes, 1974). Wet season habitats included the miombo (Brachystegia) woodlands and the Ecotone between woodlands and grasslands with grass species containing higher nutrients contents. In the dry season, eland selected for green marshes. In Pilanesberg National park, South Africa, Magome (1991) observed that eland avoided open savannas and secondary grasslands. At the same time, those avoided habitats were selected by Wildebeest, White rhino, Hartebeest and Zebra. Hence, this separation partially reduced competition between eland and these other ungulates. Avoidance of open grasslands is consistent with observations by Grobler (1974), and Wilson and Hirst (1977). However, selection for more open grassland by eland in Kenya was attributed to absence of their favoured open woodland in the areas (Sekulic, 1978). In Pilanesberg National Park, Eland used slopes in wet season and bottomlands during dry season (Magome, 1991). Bottomlands were avoided possibly due to tall grass stands with high stem to leaf ratio during the growing season.
2.8.4 Factors affecting habitat selection by ungulates Precise quantification of space use enables ecologists to measure species habitat attributes so that they can infer behaviour such as habitat selection. Johnson (1980) described habitat selection as the disproportionate use of habitat resources and Block and Brennan (1993) mention that it is scale dependent. There are many factors which can influence resource selection by ungulates including predation risk (Riginos and Grace, 2008), feed availability (Senfit et al ., 1987), water availability (Redfern et al ., 2003) and season and leaf phenology (Wilson and Hirst, 1977). Predators have direct effects on prey populations through lethal consumption and non lethal effects on prey. Lima (1998) suggested that non lethal effects of predators on prey have larger ecological impacts than actual predation.
2.8.6 Significance of suitable habitat to animal populations It is essential to have a sound understanding of the relationship between an animal and its habitat, because the way in which animal populations react to their habitat largely reflects the suitability of that habitat (Bothma, 2002). Every animal species has its own characteristic density under optimal habitat conditions. In sub optimal conditions, the social structure of animal populations may be affected to such an extent that it can lead to a decline in numbers or even cause extinction (Bothma, 2002). As a general rule, the size of the social units or herds in which animals occur is related directly to the structure of the habitat (Bothma, 2002).
CHAPTER III MATERIALS AND METHOD
3.1 DESCRIPTION OF THE STUDY AREA Chivero Recreational Park is located in the North Central parts of Manyame basin in Zimbabwe; Chivero is downstream of Harare main water shed and extends 62km 2. Its geographical position is found around latitude 30 47’S and longitude 17 54’E. The study area is divided into two the lake area covering 26 km 2 of water and park area covering 36 km 2of land (ZPWMA, 2013). The area is on an elevation with a high relief of ranging1300m to 1675m above sea level (Magadza, 2008).The climate of Chivero is wet; rainfall averages 750mm and 1125mm for the period 1996 to 2012. The mean maximum temperature was calculated for the same period is 27.3 oC and the minimum temperature is 16.7 oC.The study focused on the South Western and central part of the park bordered between the lake shore line and Park fence. The study area is illustrated in figure 3.0.
Figure 3.0 Location of the study area.
3.2 THE PHYSICAL ENVIRONMENT OF CRP
3.2.1 History of the Area The Shona people under chief Chivero historically used to inhabit the area under communal land tenure system. The peasants were then removed from the area before the proclamation of the existence of the Robert Mcllwaine was done in 1958. It was used to test the merits of preservation during animal relocation from Kariba Operation Noah.
3.2.2 Relief Chivero Recreational Park has a high relief. The altitude varies 1300 and1600 above sea level with some trig points within the Park at Bushman’s paintings. The lowest point in the park is Fraud which is on a flood plain 1286 above sea level. The terrain of the park is a angulating characterised by gentle rises and descents in the Park. This pattern is a useful hive in browse utilisation as water shed and temporary flood plains become nutrient hotspots.
3.2.3 Soils Soils are deep, coarse and outstandingly efficient in organic matter and are suitable for agriculture purpose because of their interference with the use of agricultural machinery. In the southern part, the hills exhibit a great variety, with crystalline limestone, granite, a dandled ironstone massif (mass of connected rocks to give a peak) and schist (rocks made of thin layered small rocks). The south west corner has shallow red brown clay soils formed over basic rock with ridges of shallow sand over gneissic rocks (ZIMPAKS, 2011).
3.2.4 Hydrology The rain season stretches from October/ November to March, while the dry cool season is between May and August. Frost is common in winter season while October and November are the hottest months. Apart from the main lake during the rainy season pans and swamp develop in the park.
3.3 THE BIOTIC ENVIRONMENT OF CRP
3.3.1 Wildlife Species Chivero Recreational Park supports a diverse fauna that consists of 53species of mammals, 400 species of birds, 28 species of amphibians and 50 species of fish (CRP, 2011). The mammal fauna in the area includes, Wildebeest ( Cannochaetus taurinus ), Zebra (Equus burchelli), Waterbuck (Kobus ellipsiprymnus) , Giraffe ( Giraffa camelopardalis), Steenbok (Raphicerus campestis) , Kudu (tregalaphus streptsiceros) , Eland Tregalaphus oryx) and Impala (Aepeceras melampus) which make up approximately 30% of the biomass. Unusual interesting species include Tsessebe ( Damaliscus lunatus ), Sable ( Hippotragus niger ) and White rhino (Ceratotherium Simum) . Carnivores include Serval (Felis serval) and Caracal (Felis caracal) . 3.3.2 Vegetation The major influence of vegetation is the availability of water, soil type, and forage. Chivero is dominated by brachystegia spiciformis, brachystegia bohemii and julbinardia globiflora . Uapaca kirkiana, Vangueria infausta , Strychnos cocculoides, Piliostigma thonnngii, Petrocarpus angolensis and Afezelia quanzensis are present in the park among others . The major grass type Hyparrhenia tall grass veld with common grasses like Hypethelia dissoluta , Hyperhenia filipendula, Heteropon contortus, Digitaria malijiana, Eragrostis racemosa however Heteropogon contortus, Sporobolus pyramidis, Melinis rapens, Cynodon dactylon are increaser species which become dominant when the grass is overgrazed.
3.4 Vegetation and plant inventory A vegetation and grass inventory was done and a record of all tree species found in the park were recorded and pressed, kept in an arch file for quick reference during implementation of the experimental design of feeding trail.
3.5 SAMPLING PROCEDURE Although Tregalaphus oryx is vigilant, a direct observation method was used for gathering data. The method was used involved, identifying the single herd of eland. Only feeding sites where a heard would have spent at least 10 minutes were considered sampling. At each feeding site Circular sample plots of 1m radius were determined from the central spoor along the feeding trail (Petrides, 1975). A total of 60 plots were randomly sampled along the feeding trail, 30 plots in each of the dry and wet season with the aid of an experienced tracker. Dung (pellets) of elands was collected during dry season and wet season and specific areas were recorded on the particular points they were collected. Samples were analysed by (UZ) University Of Zimbabwe laboratory for nutritive value analysis. Essentially, in this exercise, biodiversity of tree species was assessed using point centred quarter method and for grasses using the Shannon Weiner index across 60 plots.
3.6 MEASURED/RECORDED VARIABLES AND MEASUREMENT TECHNIQUES For all the selected grass species, data was collected second feeding station and recorded. The species present and their abundance, browsed and grazed parts, habitat type, species activity, number of bites were scored on count Scoring was according to the following scale: 0 = no grazing evident, 1 = very light grazing, 2 = light to moderate grazing, 3 = moderate to heavy grazing, 4 = heavy grazing and 5 = tuft completely grazed, only roots remaining and feeding height was estimated. For all the selected woody species, data was also collected second feeding station and recorded. The species present and their abundance, browsed and grazed parts, habitat type, species activity, number of bites were scored on count and feeding height was estimated.
Table 3.0 Measured/recorded variables and measurement techniques. VARIABLE TECHNIQUE Species present Species richness were recorded on physical count Species availability Braun Blanquet cover abundances (Blanquet, 1955) Browsed and grazed parts Visual observation Habitat type Visual judgement of the understory Species activity Observation ( use of binoculars) Selected species height A disc pasture meter was used to record the tallest and shortest grass and the rest were estimated between the ranges. Tree browsed heights were recorded by a vertex iv Hypsometer Number of bites A fine scale score ranking was used
All calculated variables were per plot. (3.143m 2) where A = Area and r = radius
3.7.1 Availability
P (a) =
Where P (a) is the proportional availability
3.7.2 Acceptance
P (u) =
Where P (u) is proportional utilisation The acceptance of a food type is the proportional frequency with which it was eaten (used) when encountered. Fine scale measures provide more precise differentiation of use among feed types, but feeding decisions governing acceptance are not independent when plants are encountered in clusters. In these circumstances, statistical assessments need to fall back on site based acceptance frequencies, provided these sites are sampled independently. 3.7.2.1 Acceptance and Availability Analysis Acceptance frequencies take values with the range 0– 1, and natural clustering of these values indicates divisions between feed types that are favoured (frequently eaten when encountered), neglected (rarely eaten when encountered), or rejected (never eaten when encountered (Owen Smith 1994; Owen Smith and Cooper 1987). This approach eludes some of the problems encountered in interpreting selection from ratios between proportional use and availability estimated independently: arbitrary decisions about what is effectively available within some broad foraging area; spurious divisions between positively and negatively selected feed types; and unbounded upper values of such ratios (Owen Smith and Cooper 1987a).
3.7.3 Feed preference index FPI =
Where FPI is Feed Preference Index, P (u) is proportional utilisation and P (a) is the proportional availability.
3.7.4 Diet contribution DC = NB*(Pa.Pu)
Where DC is diet contribution, NB is Number Bites, P (u) is proportional utilisation and P (a) is the proportional availability. A measure of the dietary contribution by each plant species was derived by multiplying the number of records of consumption of each plant part for that species by the product of the availability and acceptance frequency per site. This approximation was used because it was difficult to quantify objectively the actual dietary contribution by mass of the wide range of available plant species and parts. The relative dietary contribution was then calculated by dividing the dietary contribution of each species by the summed dietary contributions across all species consumed. Similar calculations were used to estimate the relative dietary importance of particular plant parts and height classes. For measures of use, 95% confidence intervals were calculated, assuming sites to be replicate samples.
3.8 DATA ANALYSIS Data was tested for normality using Kolmogorov Smirnov test in SPSS version 21 Statistical Package for Social Sciences (SPSS, Zar 2006) and it was normal after log transformations. Data on diet contribution across species in each season were analysed using One Way Anova. Seasonal variation on diet contribution, of fed species between wet and dry season was analysed using Mann Whitney U test because data was non normal between seasons. Feed preference index was analysed using (non parametric) Kruskal Wallis one way ANOVA in each season and Mann Whitney between seasons because data was non normal after normality tests using Kolmogorov Smirnov test. Feed preference data within dry season were transformed using log 10 , ln, square root and exponent but, remained skewed. Independent t test was used to analyse data on dung samples and dietary diversity between seasons. Shannon Wiener indices were analysed using Pearson correlation coefficient (r s) bivariate analysis.
CHAPTER IV
RESULTS
4.1 INTRODUCTION This chapter presents the collected data in form of tables, graphs and inferential statistics.
4.2 Diet Contribution within Dry Season The different grass species contributed significantly to the diet with values, F = 17.9, df 4, 108 and (P < 0.001).
FIG. 4.0 Dietary contribution of grass species constituting in the eland diet during the dry season (upper 95% confidence limits are indicated).
A total of 5 grass species were sampled from 30 plots. A (total area = 94.29m 2), Heteropogon contortus and Brachiaria brizantha contributing significantly. There is no significant difference between Digitaria milanjiana Schizachyrium jeffreysii and Ranchelytrum Rapens . Schizachyrium jeffreysii was taken to be the reference group since it had the lowest diet contribution.
4.2.1 Diet Contribution within Wet season The species contributed to the diet with F = 16.4, df 8, 188 and (P < 0.001).
FIG. 4.1 Dietary contribution of grass species constituting in the eland diet during the wet season, (upper 95% confidence limits are indicated). A total of 5 grasses were sampled from 30 independent plots. Acroceras macrum, Heteropogon Contortus, Panicum maximum and Schizachyrium jeffreysii contributed significantly from Schizachyrium semiberbe . Schizachyrium jeffreysii was taken to be the reference group since it had the lowest diet contribution.
4.2.3 Dietary Contribution between Dry and Wet Seasons Data were tested using Mann Whitney U test between the wet and dry season. The dietary contribution of woody and herbaceous plants was highly significantly different between seasons with values, (median ± SD) = (0.3882 ± 1.090), Z = 4.021 and (P < 0.001).
4.3 Feed preference Index within Dry season The grass species feed preference index of elands was significantly different in the dry season with values, H = 52.6, df 4 and (P < 0.001).
4.3.1 Feed preference index within wet season The grass species feed preference index showed a significant difference in the wet season,
with values: H = 15.3, df 7 and (P = 0.033)
FIG. 4.2.Feed preference Index box plots of grass species constituting the eland diet during the dry and wet season in Chivero, at (95% confidence are indicated).
4.3.2 Feed Preference between Dry and Wet seasons The woody and grass species feed preference index was significantly different between wet and dry season. The (mean ± SD) were (1.070 ± 3.64), Z = 0.41 and (P = 0.68) to 3sf illustrating no significant difference between dry and wet season.
Fig. 4.3 Patch based acceptance frequency versus availability for 9 grass species with adequate samples for, a) dry season b) wet season. Species acronyms: R.rep Rhynchelytrum repens ; S.Jeff Schizachyrium jeffreysii ; D.mila Digitaria milanjiana ;H.cont Heteropogon Contortus ; B.briz Brachiaria brizantha ; S.serm Schizachyrium semiberbe ; E.rac Eragrostis Racemosa ; M.rap Melinis rapens ; A.macr Acroceras macrum ; P.max Panicum maximum and R.rep Rhynchelytrum repens .
Fig. 4.4 Patch based acceptance frequency versus availability for 11 woody plant species with adequate samples for a) dry season and b) wet season. Species acronyms: F.Ind Flacourtia indica ; B.spe Brachystegia spiciformis ; J.glo Julbernardia globiflora ; S.viro Secrunega virosa ; C.mol Combretum molle ;C.zey Combretum zeyheri ;A.Car Acacia karroo ;G.Fla Grewia flava ;D.Ron Dombeya rotundifolia and Z.muc Ziziphus mucronata
Table 4.0. Patch Based Eland faecal samples in Chivero analysed using Independent T test, the table illustrates t value, df value and p value, above values indicate wet season and below bracketed indicate dry season.
Parameters Nutritive Elements Na Mg Ca N P K S Fe mean±SE 0.137±0.00279 0.0660±0.00812 0.0669±0.1762 0.1024±0.02334 0.28±0.05148 1.234±0.1433 0.1100±0.4506 0.4268±0.15905 0.137±0.00279 0.2000±0.15403 0.3375±0.17898 0.0970±0.01973 0.309±0.07504 1.472±0.18117 0.7180±0.23353 0.584±0.15306 t value wet 0.000 0.889 1.505 0.177 0.319 1.030 2.556 0.712 (dry) 0.000 0.889 1.505 0.177 0.319 1.030 2.556 0.712 df value wet 8 8 8 8 8 8 8 8 (dry) (8.00) (4.023) (4.078) (7.788) (7.082) (7.597) (4.297) (7.988) p value E ass 1.00 0.400 0.171 0.864 0.758 0.333 0.034 0.497 E not assumed 1.00 0.424 0.206 0.864 0.759 0.335 0.059 0.497
4.4 Faecal Samples Nutritive elements were tested using Independent T test and they had no significant differences between Dry and Wet season except only for Sulphur which differs between wet and dry season.
4.4.1 ACCEPTANCE AND AVAILABILITY CORRELATION IN SEASON Table 4.1 The table below shows Pearson Correlation between availability and acceptance by an eland within its home range in Chivero Recreational Park. Variable Pearson Correlations
(r s) P values Overall 0.25 0.631 Acroceras macrum 0.016 0.944 Brachiaria brizantha 0.218 0.113 Digitaria milanjiana 0.327 0.185 Eragrostis Racemosa 0.243 0.347 Heteropogon Contortus 0.138 0.330 Melinis rapens 0.149 0.486 Panicum miximum 0.309 0.152 Rhynchelytrum repens 0.048 0.782 Schizachyrium jeffreysii 0.195 0.205 Schizachyrium semiberbe 0.125 0.588
4.5 Dietary Diversity Diversity indices were calculated using Shannon Weiner index (H' = - ) per plot. Data was skewed to the left and was exponent transformed to meet the requirements of Independent t test. Eland grass dietary diversity was significantly different between seasons with (mean ± SE) = (2.71 ± 0.10), t = 8.032, df = 8 and (P < 0.001).
FIG. 4.5.Shannon Weiner Dietary diversity Index mean graph of grass species constituting the eland diet between the dry and wet season in Chivero, upper and lower 95% confidence limits are indicated
4.1 Wet Season Feed Preference A total of 15 wet season trees feeding stations were sampled and 13 different tree species were being utilized. A total of 30 grass feeding stations were randomly sampled along feeding trail and 9 grass species were being utilized. Ziziphus mucronata was highly preferred as compared to other tree species and Heteropogon contortus was highly preferred as compared to other grass species.
4.2 Wet Season Principal/primary Feed Dichrostachys cinerea was seen as the principal feed species of the eland antelope in Chivero Recreational Park. In grasses which were being utilized, Heteropogon contortus was the principal feed species.
4.3 Dry Season Feed Preference A total of 15 dry season trees feeding stations were sampled and 12 different tree species were being utilized. A total of 30 grass feeding stations were randomly sampled along a feeding trail and 5 grass species were being utilized. Grewia flava was highly preferred as compared to other tree species and Brachiaria brizantha was highly preferred as compared to other grass species. 4.4 Dry Season Principal/primary Feed Dichrostachys cinerea was seen as the principal feed species of the eland in Chivero Recreational Park. In grasses which were being utilized, Heteropogon contortus were the principal feed species.
4.5 Seasonal Variation on Principal/primary and Preferred Feed Species In the wet season the eland antelope highly preferred Ziziphus mucronata and in the dry season they highly preferred Grewia flava . In the grasses utilized, they highly preferred Heteropogon contortus in the wet season and Brachiaria brizantha in the dry season. Dichrostachys cinerea was the principal feed species in both wet season and dry season. In grasses, Heteropogon contortus were principally fed in both wet and dry season.
Table 4.2: Feed Preference Ratings of different woody and herbaceous plants in CRP (Atkinson, 1995) Rating Category * Wet Season * Dry Season Trees Grasses Trees Grasses ≥ 2 High Z. mucronata Nil G. flava 0.74 < FPI < 2 Medium C. molle H. contortus D. rotundifolia B. brizantha D. cinerea A. macrum D. cinerea D. malinjiana R. repens C. zeyheri H. contortus P. maximum Z. mucronata S. jeffreysii A. karroo S. incanum 0.1 < FPI < 0.75 Low F. indica B. brizantha B. speciformis R. repens J. globiflora S. Sermibebe J. globiflora S. jeffreysii C. Zeyheri M.rapens C. molle B. speciformis E. racemosa F. indica S. virosa
FPI < 0.01 Very low Nil Nil Nil Nil CHAPTER V
DISCUSSION
5.1 DIET COTRIBUTIONS
5.1.2 Diet contributions within Dry Season Results in the dry season show that diet contribution was significantly different with plant species respectively. Woody species contribution was high and grasses contributed moderately to the annual eland diet in the dry season. This pattern indicates that woody species have higher water retention during hot weathers in the tropics hence they lose water slowly as compared to grass species. The results are attributed to the different morphological structures of the woody with corky bark, waxy leaves and deep roots to improve on water storage ability and fire resistance whereas grasses have shallow rhizomatic and fibrous roots and minimum fire resistance. This is similar to Watson and Owen Smith, (2000) in the semi arid shrubland who found grasses contributing only 6% of eland annual diet. However the outcome also concurs with Knoop et al , (2006) who found the roan feeding on woody plants more than grasses in the dry season.
5.1.3 Diet contribution within Wet Season The observations were that, the diet contribution was significantly different with plant species respectively. Woody species contributed moderately and grass species highly of annual diet in wet season. This outcome is accredited to the availability of water in the wet season which will be in abundance. It is however in line with the optimal foraging theory which stipulates that the energy expended by an animal in search for feed is highly returned by the quality of feed selected. The rapid decline in grass consumption in January perhaps resulted from the maturation of grasses at this time because eland stomach structure is that of browsers, eland probably digest mature grass less well than grazers (Hofmann, 1973; Owen Smith, 1982). The result coincides with Watson et al., (2000) who found eland grass consumption peaked at the beginning of the wet season when grasses were early with green foliage.
5.1.4 Diet contributions between Wet and Dry Season Most of grass and woody species that were highly preferred, contributed significantly to the eland diet. However Grewia flava and Schizachyrium jeffreysii were neglected by the eland because of their diminutive palatable lifespan such that they quickly reach maturity. The number of bites per unit plot in the wet season was lower than that of the dry season which most likely could be a compensation for high nutrient eland diet available during the mid wet season. Grasses that quickly reach maturity stage store nutrients to the root system leading to low nutrient diet which is not favoured by the eland as compared to the tree foliar which remains fleshy except when they shed leaves in winter. This chains the concept the optimal foraging theory assumptions, patch selection feeding and negates the non selective gazing principles. The results however are analogous to Watson and Owen Smith, (2000) in Mountain Zebra National Park South Africa where they assessed diet contribution in semi arid shrubland. The angulating environment influences nutrient distribution hence of the preferred plant species since most feeding trails tracked was almost within bottomland. This is moreover similar to Knoop et al , (2006) in their study of bottom land and upland in relation to the roan antelope (hippotragus equinus ) foraging behaviour, confirming that the relative use of the upland and bottomland zones differed between years. The selective neglect for grass in the dry was compensated on trees because their loss water content and nutritive value along the year is very low.
5.2 Plant species selection The eland moderately selected both grass species and woody species in our study all year round. This is attributed to the reason that these are the available grasses and woody species that intersect with eland dietary niche. This follows Grobler (1974) as cited in (Skinner et al., 1990) that in Zimbabwe 23 species of grasses were recorded as preferred by the Eland. These include among others the Buffalo grass, Panicum maximum ; Spear grass, Heteropogon contortus ; Eragrostis jeffreysii ; Red grass, Themeda triandra and Urochloa oligotricha were recorded as being utilized on a year round basis. Wilson, (1969) and Estes, (1974) both added to the list of species utilized in this area. Wilson, (1975) states that in the Northern Transvaal, Elands showed a marked preference for Spear grass, Heteropogon contortus, and would also heavily utilize back footed brachiaria, brichairia brizantha , red grass, Themeda triandra ; Slit grass, Schizachyrium jeffreysii ; and Gum grass, Eragrostis gummiflua . Grass species preferred by eland include Eragrostis superba , Chrysopogon species and Andropogon species among others (Grobler, 1981; Wilson et al., 1977; Ben Shahar et al., 1988). Most of these grass species grow in areas with low woody cover where they have less competition for sunlight, water and nutrients (Medina et al., 1990; Pellew, 1983). Grobler (1974) added Wild pear, Dombeya rotundifolia ; Raisin bush, Grewia flava ; Fever tea, Lippia javanica , and Wild camphor bush, Tarchonanthus comphoratus , to the list of browse plants noting that the last named is an important species prior to the rains. Eland prefer new grass growth or grasses of medium height belonging to locally dominant species. Estes (1993) states that elands are mixed feeders, feed on grasses supplemented by foliage and herbs, especially those growing termite mounds since they are nutrient hotspots.
5.2.1 Feed preference Index and acceptance within the Dry season Woody species were highly accepted and limited grass species were accepted in the dry season. Preference is ascribed to the quality of the foliage; palatability and tastiness of the grass, the sweetness and sourness of the grass depend on the digestible cellulose in the grass. The elands are ruminants with rumen flora which is able to digest cellulose. This supports the patch selection foraging theory which dismisses the fact animals just feed on any veld factoring in plants being selected according to quality and quantity. The observation agrees with (Atkinson et al., 1995) who found eland selecting more woody species than grasses. The eland highly preferred Grewia Flava , medially preferred Dombeya rotundifolia and very lowly preferred Secrunega virosa among woody species. Brachiaria brizantha and Heteropogon Contortus was highly preferred and lowly preferred Schizachyrium jeffreysii among grass species. Only 2 grass species were preferred considerably during this season. Shade tolerant grass species like Panicum maximum are frequently eaten by eland, partially due to their high nutritional value and moisture content (Parinni, 2006). In Zimbabwe, Wilson (1969a) as cited in Skinner and Smithers (1990), included among browse plants utilized Sweet thorn, Acacia karroo ; Lippia oatzii ; Rhus lancea ; Silver raisin bush, Grewia monticola , and the fruits and leaves of sickle bush, Dichrostachys glomerata, and the fruits of Buffalo thorn, Ziziphus mucroanata .
5.2.2 Feed preference Index and acceptance within the Wet season Grass species contributed significantly more than woody species to the diet in the wet season. Eland highly preferred Ziziphus mucronata , and lowly preferred Flacourtia indica among woody species. Grass species, which were preferred, include the Heteropogon contortus and Brachiaria brizantha and however Schizachyrium jeffreysii was lowly preferred. The grasses that contribute much of the veld in Chivero are increaser 1 which is readily available during the wet season. The most preferred grass species are known to have higher cellulose in their cell walls.
5.2.3 Feed preference Index and acceptance between Dry and Wet Season Feed preference index varied significantly between dry and wet season. In all browsed species recorded, the eland preferred the plant tips for foraging. New tips that were very fresh were much preferred probably due to their palatability. At low browse line height, high damage in most browse species and in grass species a low moderate height was preferred. Most of the grasses accepted were perennial grasses. On grasses, they fed on highly at very low height from the ground, concentrating on leaves and stems. The eland principal/primary feeds indicated no seasonal variations. The observed ability to harvest selectively the leaves and current annual growth without also harvesting the older twigs therefore is accredited to the relative value of browse forage to herbivores. Such ability has been mentioned frequently for small mouthed ruminants such as sheep, pronghorn, and deer (Cook and Harris 1950; Meyer et al., 1957; Weir and Torell 1959; McClymont 1967; Eadie 1969; Healy 1971; Short 1977), but seldom mentioned for large mouthed ungulates such as cattle or horses. Rather, cattle do not appear to be capable of such a fine degree of selectivity, as evidenced by their browsing effects on the growth form of antelope bitterbrush (Hormay 1943).
The degree of selectivity that can be exercised by a large herbivore, within its time energy constraints, is determined largely by mouth size. Animals with small mouths are more capable of being selective of plant parts than animals with large mouths are (Meyer et al., 1957, McClymont 1967, Jarman 1974). The ability to forage selectively (determined by the time energy constraints and mouth size) is very important where there is herbivory. Whereas leaves and current annual growth of browse species may be about 65% cell soluble and 10% lignin, older twigs may be only 30% cell soluble and 20% lignin (Blair et al., 1977).
The results are in agreement with what other researchers obtained. Wilson (1969) as cited in Skinner and Smithers (1990) added Wild pear, Dombeya rotundifolia ; Raisin bush, Grewia flava to the list of preferred Eland browse species. Among the graze species, he added Buffalo grass, Panicum maximum ; Spear grass, Heteropogon contortus, Brachiaria brizantha and Schizachyrium jeffreysii. Other species cited by Grobler (1974) such as Themeda triandra , Urochloa oligotricha Eragrostis jeffreysii , Eragrostis gummiflua , Hyperthelia dissolute and Hyparrhenia hirta were not utilized by the Eland in Chivero. In addition, species such as Lippia javanica , Grewia monticola , Dichrostachys glomerata and Lippia oatzii were not recorded on the species that were preferred by the Eland. On the principal or primary feeds, there was no variation between seasons. Heteropogon contortus and Dichrostachys cinerea were the primary feeds on both seasons.
5.3 Shannon Weiner Diversity indices The diversity results show that ecosystem diversity does not change between seasons within the home range. The wet season is more diverse than the dry season. The frequency of occurrence or abundances of encountered grass species was higher in the wet season than that of the dry season because in the wet season there could be recruitment of new species. Most grass species break dormancy in the dry season soon after veld fires and hot dry weather therefore they are bound to germinate early wet season. Similar to most studies eland dietary diversity varies significantly between seasons. Contrary to Watson, (2006) eland studies in KwaZulu Natal National Park dietary diversity was lower than ecosystem diversity. Dietary diversity is higher in the wet season because rainfall reception is high hence high palatability of herbaceous plants. Ecologically selection index range is wider in wet than dry season. However since forage quality increase in the wet season where there is much water, differences in dietary diversity could be causing by instability in assimilation efficiencies between seasons. These results are similar to those found by (Owen Smith and Chafota, 1993) when they were looking at metabolic rate in relation to body size and elephant selectivity in Chobe National Park in northern Botswana around near Kasane area.
5.3.1 Residual nutritive values from faecal samples Sulphur differed significantly between the 8 elements in the dung residue. This indicates that sulphur content is not constantly assimilated efficiently or the plants probably differ in their provision of sulphur between seasons. This is attributed to the fact that eland were feeding on aged woody species and sulphur tend to bio accumulate in aged pants and that it is found as sodium sulphite (a compound) which is not readily adsorbed or assimilated by the sodium potassium pump on eland rumen membranes (Jarman, 1974). Sulphur and phosphorous among (Na, Mg, Ca, N, K and Fe) are the non metals and they tend to bio accumulate with age in leaf foliar. This explains why sulphur is more in the dry season where elands were browsing more on tree foliar than the dry season. Lake water poor with high effluent discharge, is the major drinking water point whose shore bounds the other half of the park and possibly this could be reason for the presence of heavy metals. The constancy of the other metals that did not differ between seasons is greatly related to the chemical properties of group 1 and 2 which do not have 3s orbitals hence they tend to lose electrons in the outer shell in ionic bond thus they are very reactive and readily assimilated with consistency (Owen Smith, 2002).
5.4 Pearson correlations The observations were that plant species acceptance was negatively correlated to plant species availability. This clarifies the eland as a selective herbivore, despite the available grass species in abundance eland feed by choice rather than influence of available woody or herbaceous species hence they are not generalists. This is also attributed to the fact that quality rather than quantity of feed influences preference or acceptance of an animal (Bothma, 2002). The independence of the variables showing no association is best explained the digestibility ratios which are behavioural and unique to an individual species that generally its selectivity. This again is in line with the optimal foraging theory and assimilation efficiency concepts. The results differ from Watson, (2006) in their study of eland diet in Masaimara ecosystem.
5.5 Competition with other species Eland prefers to browse at medium height; however some animal species prefer the same feed species as the eland in Chivero. These include the kudu, impala, sable, wildebeest and waterbucks. Impalas are the most in abundant species in Chivero. Their abundance might be a great threat to the eland in terms of competition for feed. They may make the feed unavailable to the eland due to their feeding behaviour. Ideally eland prefer grasses of medium height of which this can be negatively affected or contested by the impala or kudu since they graze reducing the height of the grass to above than 30cm in height of which it becomes unavailable to the eland (Skinner and Smithers, 1990). Waterbucks and wildebeests add to the animal species that compete for feed with the eland however they numbers are low as compared to the impala population. The elands might be in equilibrium competition since both species show low numbers of new individuals and natality rate.
5.6 Eland distribution influenced by feed Eland were found in the western part of Chivero were there is much of Heteropogon contortus and open woodland. They were also found close to the lake and pans where there was cover. This is in agreement with Skinner and Smithers, (1990) cited that elands are savanna woodland species, dependent on cover and availability of water. They prefer open woodland with adjacent vleis or grassland with medium to high stands of grass. During the dry season, elands were also found in areas that were burnt during early burning. They were utilizing new shoots that were fresh and this was supported by Estes, (1993) when he cited that eland favours grasslands that produce new growth after the annual fires in the dry season. Preferred spices influenced habitat selection and general distribution to the eastern park and this was similar to (Skinner and Smithers in 1990) their study was prompted by the lack of initial increase by the Eland introduced into the Pilanesberg Game Reserve in North West Province, South Africa; 67 animals released between 1979 and 1983 had only grown to approximately 70 animals by 1988 (Skinner and Smithers, 1990). We recorded forage selection by eland within the context of the landscape units favoured in different seasons. Chrysopogon serrulatus , Panicum maximum , Heteropogon contortus , and Themeda triandra contributed most to the diet of eland. Faecal crude protein content did not drop below 6.6% of dry matter during the dry season, with use of burnt grassland by eland contributing to an elevation in faecal protein levels at the beginning of the wet season (Skinner and Smithers, 1990). The Eland population had increased to 127 animals by 1991, suggesting that the earlier lack of population growth had been due to below average rainfall, lack of burns providing green regrowth or top hamper during the dry season, or a delay in learning to exploit available forage resources efficiently. The habitat is that area in which an animal occurs by choice (Bothma, 2002).
CHAPTER VI
CONLUSION AND RECOMMENDATIONS
6.1 Conclusion In conclusion, selected feed species by the eland in Chivero Recreational Park differs between wet and dry season, eland diet selection is not significantly correlated with plant availability and eland diet does not have a higher Shannon Weiner diversity than both available and eaten plant species hence available feed in Chivero does not meet the minimum requirements of eland diet.
6.2 Recommendations The researcher recommends that planned burning should be done in areas where elands are much concentrated so as to facilitate the growth of new fresh shoots that can be utilized during the dry season and early in the rain season. Burning small patches in e land habitats may not attract huge concentration of competitors. This would be more effective if burning of bigger patches outside eland areas would be implemented at the same time in such a manner that the green flushes of grass would occur at about the same time in both areas. The above could likely reduce competition and predation risk in habitats of highest value to eland (i.e. create refuge where eland can escape from competition and predators). A viable eland population should be introduced so as to enable the populations to increase. A sound carrying capacity should be introduced to avoid overutilization of the habitat that may lead to deterioration of range condition and even to range destruction. Of the forage species present in an area, those with the highest and lowest preference ratings are especially useful as indicators of stocking density and range condition. This study provided baseline data on the feeding ecology of the eland in Chivero. However, further researches on the distribution and abundance of preferred and accepted feeds of the eland should be carried out. Abundance of preferred and principal feed species has an effect on the production and growth of animals (Petrides, 1975). A study to assess other areas of the park in terms of distribution and abundance of accepted and principal feed will help in re introductions of the eland in Chivero. Habitat suitability assessment should be conducted in order to ascertain if the habitat is conducive for the eland. A research on the distribution of the eland should also be carried out. An assessment on the abundance of the Eland competitors should be done as well to see if competitors are not too many in the park. A research related to lake water quality effect on animal diet contribution. An assessment on the availability of water source during the dry season necessitates a further study since eland are water dependent animals.
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Appendix A: dry season diet contribution
Tests of Between-Subjects Effects Dependent Variable: ln diet con Source Type III Sum of df Mean Square F Sig. Squares Corrected Model 196.187 b 4 49.047 17.949 .000 Intercept 405.971 1 405.971 148.570 .000 Species 196.187 4 49.047 17.949 .000 Error 295.113 108 2.733 Total 826.794 113 Corrected Total 491.300 112 a. season = dry b. R Squared = .399 (Adjusted R Squared = .377)
Parameter Estimates Dependent Variable: ln diet contribution Parameter B Std. Error t Sig. 95% Confidence Interval Lower Bound Upper Bound Intercept 3.573 .352 10.138 .000 4.272 2.874 [Species=Brachiaria brizantha] 3.195 .467 6.836 .000 2.268 4.121 [Species=Digitaria milanjiana] 1.211 .525 2.305 .023 .169 2.252 [Species=Heteropogon 3.054 .475 6.433 .000 2.113 3.995 Contortus] [Species=Rhynchelytrum .714 .534 1.337 .184 .344 1.772 rapens] [Species=Schizachyrium 0b . . . . . jeffreysii] a. season = dry b. This parameter is set to zero because it is redundant.
Appendix B wet season diet contribution
Tests of Between-Subjects Effects Dependent Variable: ln diet contribution Source Type III Sum of df Mean Square F Sig. Squares Corrected Model 429.446 b 8 53.681 16.402 .000 Intercept 2291.891 1 2291.891 700.268 .000 Speciesp 429.446 8 53.681 16.402 .000 Error 615.301 188 3.273 Total 3271.616 197
Parameter Estimates Dependent Variable: ln diet contribution Parameter B Std. Error t Sig. 95% Confidence Interval Lower Bound Upper Bound Intercept 5.002 .395 12.669 .000 5.780 4.223 [Species=Acroceras macrum] 1.594 .558 2.855 .005 .492 2.695 [Species=Brachiaria brizantha] .768 .536 1.434 .153 .289 1.824 [Species=Eragrostis Racemosa] .551 .590 .934 .352 .613 1.716 [Species=Heteropogon 4.619 .536 8.625 .000 3.562 5.675 Contortus] [Species=Melinis rapens] .496 .541 .918 .360 .570 1.562 [Species=Panicum miximum] 3.437 .546 6.294 .000 2.360 4.514 [Species=Rhynchelytrum 1.073 .573 1.872 .063 .057 2.202 rapens] [Species=Schizachyrium 1.552 .552 2.812 .005 .463 2.641 jeffreysii] [Species=Schizachyrium 0b semiberbe] a. season = wet
Appendix C. Mann Whitney U test and Wilcoxon W
Test Statistics Diet cont Chi Square 7873.558 df 297 Asymp. Sig. .000
Ranks season N Mean Rank Sum of Ranks 1 266 190.85 50765.50 Diet con 2 150 239.80 35970.50 Total 416
Test Statistics Diet con Mann Whitney U 15254.500 Wilcoxon W 50765.500 Z 4.021 Asymp. Sig. (2 tailed) .000 a. Grouping Variable: season
Ranks season N Mean Rank Sum of Ranks 1 243 188.68 45849.50 FPI 2 130 183.86 23901.50 Total 373
Test Statistics a FPI Mann Whitney U 15386.500 Wilcoxon W 23901.500 Z .413 Asymp. Sig. (2 tailed) .680 a. Grouping Variable: season
Appendix D. Tables showing calculated Diet contribution Acceptance and Fpi Wet season trees Species FO Pa NB Acc/(Pu) FPI DC RDC Ziziphus mucronata 6 0.04 116 0.3 7.5 1.392 0.6280 Combretum zeyheri 15 0.1 49 0.13 1.3 0.637 0.0287 Dichrostachys cinerea 57 0.35 138 0.4 1.14 19.32 0.8710 Flacourtia indica 5 0.03 9 0.02 0.7 0.027 0.0012 Julbernardia globiflora 53 0.3 24 0.1 0.3 0.720 0.0325 Combretum molle 23 0.14 15 0.04 0.3 0.084 0.0038 Brachystegia spiciformis 6 0.04 3 0.01 0.3 0.001 0.0001 Totals 165 100% 354 100% 22.18
Wet season grasses SPICIES (FO) Pa % NB Pu/Acc FPI D C R. DC Schizachyrium jeffreysii 234 0.113 104 0.103 0.912 1.21 0.0373 Acroceras macrum 220 0.106 94 0.093 0.877 0.927 0.0286 Rhynchelytrum repens 159 0.077 71 0.07 0.909 0.383 0.0118 Heteropogon Contortus 464 0.224 326 0.323 1.442 23.587 0.7267 Panicum miximum 342 0.165 182 0.181 1.1 5.435 0.1675 Brachiaria brizantha 185 0.089 74 0.073 0.82 0.481 0.0148 Schizachyrium semiberbe 141 0.068 45 0.045 0.662 0.138 0.0043 Eragrostis Racemosa 184 0.089 49 0.049 0.551 0.0214 0.0007 Melinis rapens 146 0.07 63 0.062 0.886 0.273 0.0084 Grand totals 2075 1 1008 1 32.4554 1
Dry season trees Species FO Pa NB Pu FPI DC R. DC Grewia flava 9 0.04 70 0.1 2.5 0.028 0.001 Dombeya rotundifolia 23 0.1 101 0.13 1.3 1.313 0.0471 Dichrostachys cinerea 61 0.3 201 0.3 1 18.09 0.6489 Combretum zeyheri 21 0.1 50 0.1 1 0.5 0.0179 Ziziphus mucronata 34 0.2 178 0.2 1 7.12 0.2554 Acacia karroo 12 0.1 77 0.1 1 0.77 0.0276 Solanum incanum 10 0.04 30 0.04 1 0.048 0.0017 Brachystegia spiciformis 5 0.02 4 0.01 0.5 0.0008 0.00003 Julbernardia globiflora 8 0.03 3 0.004 0.13 0.00036 0.00001 Combretum molle 12 0.1 9 0.01 0.1 0.009 0.0003 Flacourtia indica 8 0.03 2 0.002 0.1 0.00012 0.000004 Secrunega virosa 9 0.04 3 0.004 0.1 0.00048 0.00002 Totals 212 100% 728 100% 27.87976
Dry season grasses SPICIES FO Pa % NB Pu/Acc FPI D C R. DC Digitaria milanjiana 103 0.122 71 0.128 1.049 1.109 0.0252 Rhynchelytrum repens 92 0.109 51 0.092 0.835 0.511 0.0116 Heteropogon Contortus 283 0.336 178 0.321 0.955 19.198 0.4357 Brachiaria brizantha 252 0.299 205 0.37 1.237 22.679 0.5148 Schizachyrium jeffreysii 112 0.136 48 0.086 0.632 0.561 0.0127 Grand totals 842 1 553 1 44.058 1
Appendix E. showing browsed heights
SPICIES 10(cm) 20(cm) 30(cm) 40(cm) 50(cm) 60(cm) 70(cm) 80(cm) 90(cm) Schizachyrium jeffreysii 1 4 6 3 1 6 Acroceras macrum 2 7 5 4 3 1 Rhynchelytrum repens 1 3 2 6 2 2 2 Heteropogon Contortus 5 5 8 5 1 3 1 1 Panicum miximum 1 2 3 5 1 7 Brachiaria brizantha 4 4 5 5 1 4 2 Schizachyrium semiberbe 3 1 4 3 3 4 Eragrostis Racemosa 3 3 2 3 3 2 1 1 Melinis rapens 2 8 6
Overall feeding height 5 31 25 46 30 12 28 6 1
SPICIES 10(cm) 20(cm) 30(cm) 40(cm) 50(cm) 60(cm) 70(cm) 80(cm) 90(cm)
Schizachyrium jeffreysii 1 4 6 3 1 6
Acroceras macrum 2 7 5 4 3 1
Rhynchelytrum repe ns 1 3 2 6 2 2 2
Heteropogon Contortus 5 5 8 5 1 3 1 1
Panicum miximum 1 2 3 5 1 7
Brachiaria brizantha 4 4 5 5 1 4 2
Schizachyrium semiberbe 3 1 4 3 3 4
Eragrostis Racemosa 3 3 2 3 3 2 1 1
Melinis rapens 2 8 6
Overall feeding hei ght 5 31 25 46 30 12 28 6 1
SPICIES 10(cm) 20(cm) 30(cm) 40(cm)
Digitaria malanjiana 1 11 12 3
Rhynchelytrum repens 8 14 4
Heteropogon Contortus 1 8 8 7
Brachiaria brizantha 2 12 11 2
Schizachyrium jefferysii 18 9 2
Overall feeding height 4 57 54 18
Appendix F Multiple Comparisons Dependent Variable: ln diet contribution Post Hoc
LSD (I) sppp (J) sppp Mean Std. Sig. 95% Confidence Interval Difference (I- Error Lower Upper J) Bound Bound Brachiaria brizantha -1.2446 * .49705 .013 -2.2228 -.2665 Digitaria milanjiana -1.0456 .62082 .093 -2.2673 .1761 Eragrostis Racemosa 1.0426 .63058 .099 -.1983 2.2835 Heteropogon Contortus -2.9543 * .49972 .000 -3.9377 -1.9709 Melinis rapens 1.0977 .57752 .058 -.0388 2.2342 Acroceras macrum Panicum miximum -1.8429 * .58335 .002 -2.9908 -.6949 Rhynchelytrum repens .0161 .53071 .976 -1.0283 1.0605 Schizachyrium jeffreysii .1034 .51263 .840 -.9054 1.1122 Schizachyrium 1.5938 * .59646 .008 .4200 2.7676 semiberbe Acroceras macrum 1.2446 * .49705 .013 .2665 2.2228 Digitaria milanjiana .1990 .52603 .705 -.8362 1.2342 Eragrostis Racemosa 2.2873 * .53751 .000 1.2295 3.3450 Heteropogon Contortus -1.7097 * .37552 .000 -2.4486 -.9707 Brachiaria brizantha Melinis rapens 2.3423 * .47416 .000 1.4092 3.2754 Panicum miximum -.5982 .48124 .215 -1.5453 .3488 Rhynchelytrum repens 1.2607 * .41587 .003 .4423 2.0791 Schizachyrium jeffreysii 1.3480 * .39253 .001 .5756 2.1205 Schizachyrium 2.8384 * .49705 .000 1.8603 3.8166 semiberbe Acroceras macrum 1.0456 .62082 .093 -.1761 2.2673 Brachiaria brizantha -.1990 .52603 .705 -1.2342 .8362 Eragrostis Racemosa 2.0882 * .65366 .002 .8019 3.3746 Heteropogon Contortus -1.9087 * .52856 .000 -2.9488 -.8685 Melinis rapens 2.1433 * .60265 .000 .9573 3.3292 Digitaria milanjiana Panicum miximum -.7972 .60823 .191 -1.9942 .3997 Rhynchelytrum repens 1.0617 .55794 .058 -.0363 2.1597 Schizachyrium jeffreysii 1.1490 * .54077 .034 .0848 2.2132 Schizachyrium 2.6394 * .62082 .000 1.4177 3.8611 semiberbe Acroceras macrum -1.0426 .63058 .099 -2.2835 .1983 Brachiaria brizantha -2.2873 * .53751 .000 -3.3450 -1.2295 Digitaria milanjiana -2.0882 * .65366 .002 -3.3746 -.8019 Heteropogon Contortus -3.9969 * .53998 .000 -5.0595 -2.9343 Melinis rapens .0551 .61269 .928 -1.1506 1.2608 Eragrostis Racemosa Panicum miximum -2.8855 * .61819 .000 -4.1020 -1.6689 Rhynchelytrum repens -1.0265 .56878 .072 -2.1458 .0928 Schizachyrium jeffreysii -.9392 .55194 .090 -2.0254 .1469 Schizachyrium .5512 .63058 .383 -.6897 1.7921 semiberbe Acroceras macrum 2.9543 * .49972 .000 1.9709 3.9377 Brachiaria brizantha 1.7097 * .37552 .000 .9707 2.4486 Digitaria milanjiana 1.9087 * .52856 .000 .8685 2.9488 Eragrostis Racemosa 3.9969 * .53998 .000 2.9343 5.0595 Melinis rapens 4.0520 * .47696 .000 3.1134 4.9906 Heteropogon Contortus Panicum miximum 1.1114 * .48400 .022 .1590 2.0639 Rhynchelytrum repens 2.9704 * .41905 .000 2.1457 3.7950 Schizachyrium jeffreysii 3.0577 * .39590 .000 2.2786 3.8368 Schizachyrium 4.5481 * .49972 .000 3.5647 5.5315 semiberbe Acroceras macrum -1.0977 .57752 .058 -2.2342 .0388 Brachiaria brizantha -2.3423 * .47416 .000 -3.2754 -1.4092 Digitaria milanjiana -2.1433 * .60265 .000 -3.3292 -.9573 Eragrostis Racemosa -.0551 .61269 .928 -1.2608 1.1506 Heteropogon Contortus -4.0520 * .47696 .000 -4.9906 -3.1134 Melinis rapens Panicum miximum -2.9405 * .56397 .000 -4.0504 -1.8307 Rhynchelytrum repens -1.0816 * .50933 .035 -2.0839 -.0793 Schizachyrium jeffreysii -.9943 * .49046 .044 -1.9595 -.0291 Schizachyrium .4961 .57752 .391 -.6404 1.6326 semiberbe Panicum miximum Acroceras macrum 1.8429 * .58335 .002 .6949 2.9908 Brachiaria brizantha .5982 .48124 .215 -.3488 1.5453 Digitaria milanjiana .7972 .60823 .191 -.3997 1.9942 Eragrostis Racemosa 2.8855 * .61819 .000 1.6689 4.1020 Heteropogon Contortus -1.1114 * .48400 .022 -2.0639 -.1590 Melinis rapens 2.9405 * .56397 .000 1.8307 4.0504 Rhynchelytrum repens 1.8589 * .51593 .000 .8436 2.8742 Schizachyrium jeffreysii 1.9462 * .49731 .000 .9676 2.9249 Schizachyrium 3.4367 * .58335 .000 2.2887 4.5847 semiberbe Acroceras macrum -.0161 .53071 .976 -1.0605 1.0283 Brachiaria brizantha -1.2607 * .41587 .003 -2.0791 -.4423 Digitaria milanjiana -1.0617 .55794 .058 -2.1597 .0363 Eragrostis Racemosa 1.0265 .56878 .072 -.0928 2.1458 Heteropogon Contortus -2.9704 * .41905 .000 -3.7950 -2.1457 Rhynchelytrum repens Melinis rapens 1.0816 * .50933 .035 .0793 2.0839 Panicum miximum -1.8589 * .51593 .000 -2.8742 -.8436 Schizachyrium jeffreysii .0873 .43436 .841 -.7675 .9421 Schizachyrium 1.5777 * .53071 .003 .5334 2.6221 semiberbe Acroceras macrum -.1034 .51263 .840 -1.1122 .9054 Brachiaria brizantha -1.3480 * .39253 .001 -2.1205 -.5756 Digitaria milanjiana -1.1490 * .54077 .034 -2.2132 -.0848 Eragrostis Racemosa .9392 .55194 .090 -.1469 2.0254 Heteropogon Contortus -3.0577 * .39590 .000 -3.8368 -2.2786 Schizachyrium jeffreysii Melinis rapens .9943 * .49046 .044 .0291 1.9595 Panicum miximum -1.9462 * .49731 .000 -2.9249 -.9676 Rhynchelytrum repens -.0873 .43436 .841 -.9421 .7675 Schizachyrium 1.4904 * .51263 .004 .4816 2.4992 semiberbe Acroceras macrum -1.5938 * .59646 .008 -2.7676 -.4200 Brachiaria brizantha -2.8384 * .49705 .000 -3.8166 -1.8603 Digitaria milanjiana -2.6394 * .62082 .000 -3.8611 -1.4177 Eragrostis Racemosa -.5512 .63058 .383 -1.7921 .6897 Schizachyrium Heteropogon Contortus -4.5481 * .49972 .000 -5.5315 -3.5647 semiberbe Melinis rapens -.4961 .57752 .391 -1.6326 .6404 Panicum miximum -3.4367 * .58335 .000 -4.5847 -2.2887 Rhynchelytrum repens -1.5777 * .53071 .003 -2.6221 -.5334 Schizachyrium jeffreysii -1.4904 * .51263 .004 -2.4992 -.4816 Based on observed means. The error term is Mean Square (Error) = 3.736. *. The mean difference is significant at the .05 level.