Age structure and grouping behaviour of elephants in Serengeti and Mikumi National Parks in Tanzania.

doi:10.21203/rs.3.rs-1744068/v1

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Age structure and grouping behaviour of elephants in Serengeti and Mikumi National Parks in Tanzania.

https://doi.org/10.21203/rs.3.rs-1744068/v1

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African elephants, Loxodonta africana, are mega-herbivores that utilise a variety of forage. Their large body size make them tolerant to diets of low nutritional quality. Subsequently, they mostly occur in moist-dystrophic savannas but also arid-eutrophic savannas. The arid-eutrophic savannas are characterised by nutrient-rich soils and small biomass of high quality forage while the moist-dystrophic savannas are characterised by nutrient-poor soils and large biomass of low quality forage. Female elephants are social, forming family groups consisting of genetically related individuals and young animals of both sexes. The social behaviour is influenced by forage availability which determine competition between group members. The differences in forage quantity between the savannas are expected to influence elephants grouping and reproduction. I predicted the elephants to form larger groups and to have higher reproductive efficiency in dystrophic savannas. I studied grouping behaviour and age structure of elephants in eutrophic Serengeti and dystrophic Mikumi National Parks in Tanzania during the dry season. I used park roads as transects, and when elephants were sighted, the car was stopped for data recording. Group size, group type (bachelor or family), and age composition of elephants were determined through direct observations. The Serengeti and Mikumi elephant populations differed in grouping behaviour and age structure, but opposite to my predictions. Serengeti had larger family groups and a larger proportion of young elephants 0–15 years old than Mikumi. The size of family groups differed between the parks while bachelor groups were similar. Further studies are recommended to compare elephant populations in contrasting savannas.

Loxodonta africana

Mikumi National Park

Serengeti National Park

arid-eutrophic savanna

moist-dystrophic savanna

poaching.

African savannas are traditionally classified as arid-eutrophic (nutrient-rich) and moist-dystrophic (nutrient-poor) (Huntley, 1982; Charles-Dominique et al., 2016; Mukwada, 2018). The classification is based on whether soil nutrients or soil water limit plant productivity and quality (Bell, 1982; Scholes, 1990; Colgan et al., 2012; Case and Staver, 2018). In savannas with low precipitation, moisture usually limits plant growth before soil nutrients are exhausted, leading to the production of little plant biomass of high nutritive value (Huntley, 1982; Staver et al., 2017). Where precipitation is high plant biomass production is high, however, leaching of soil nutrients decreases the nutritive value of the forage (Olff et al., 2002). On a large scale, the division follows annual precipitation, but on a landscape scale many factors are important, such as position in the soil catena (Scholes, 1990), former human land-use (Fox et al., 2015), and fire and herbivory itself (Fritz et al., 2002; Sankaran et al., 2008). Soil nutrient status plays a role, and where mean annual precipitation is comparatively low, nutrient-rich soils carry eutrophic savannas, while nutrient-poor soils carry dystrophic savannas (Scholes, 1990). This condition offers two savanna types with similar rainfall, as with Serengeti National Park on soils derived from volcanic ashes (Anderson et al., 2008) and Mikumi National Park on poor sand soils (Backéus et al., 2006).

The difference in quantity and quality of forage between the savannas determine herbivore composition based on the Jarman-Bell principle (Bell, 1971; Jarman, 1974; Augustine and McNaughton, 2006). Small to medium-sized ruminant herbivores with relatively high metabolic requirements need high quality forage, thus, dominate the eutrophic savannas (Olff et al., 2002; Owen-Smith, 2013). By taking many small bites, the small herbivores reduce the plant biomass leaving too little for the large herbivores (Augustine and Mcnaughton, 2004). Large-bodied species of ruminants and hind-gut fermenters with low metabolic requirements need much forage each but tolerate low quality forage, thus dominating the dystrophic savannas (Fritz et al., 2002; Olff et al., 2002).

African elephants, Loxodonta africana, are hind-gut fermenters and mega-herbivores (adults weighing > 1 ton) (Owen-Smith, 1992). They are flexible regarding their diet, consuming large quantities of forage and drinking water (Owen-Smith, 1992; du Toit et al., 2014). Elephants are less selective in dietary choice because they have low nutrient requirements per unit of body mass due to the differential scaling coefficients of metabolism and gut size (Jarman, 1974; Demment and Van Soest, 1985; Owen-Smith, 1992). Being hindgut fermenters elephants have a high passage rate of the ingesta, allowing them to utilise large quantities of fibrous forage (Bell, 1971; Clauss et al., 2003; Clauss et al., 2007). These factors make elephants good inhabitants of the dystrophic savannas where they constitute half or more of the metabolic biomass (Owen-Smith, 2013; Skarpe et al., 2014a). However, elephants are sexually dimorphic, where males are bigger than females (Owen-Smith, 1992; Stokke and du Toit, 2000). Based on the body size hypothesis, female elephants and calves have higher nutritional needs per unit body mass compared to males (Stokke and du Toit, 2000; Shannon et al., 2006; Woolley et al., 2011). As a result, the nutrient rich savannas meet the nutritional demand of the female elephants and the young elephants (Mramba and Mlingi, 2021).

Elephants utilise grasses during the wet season, switching to more browsing during the dry season when grasses are mature and depleted (Codron et al., 2006; Kos et al., 2012). Despite their tolerance to low quality forage, elephants seem to be affected by nutrient insufficiency and plant secondary metabolites (Jachmann and Bell, 1985; Owen-Smith and Chafota, 2012). They prefer forages with high protein (Ward et al., 2017) and minerals (Holdo and McDowell, 2004); avoiding plant secondary compounds (Owen-Smith and Chafota, 2012). Our feeding study in Serengeti and Mikumi National Parks showed differences in the feeding behaviour of elephants between the parks (Mramba et al., 2019). While Serengeti elephants switched to browsing in the dry season, Mikumi elephants utilised grasses in all seasons, possibly avoiding chemical defences of the miombo.

Female elephants are social, forming family groups of 2 to 20 or more animals, consisting of genetically related females and young animals of both sexes, often accompanied by one or two non-family adult males (Moss et al., 2011). Males that have left the family groups at puberty form small bachelor groups or range independently (Chiyo et al., 2011; Moss et al., 2011). Family groups are flexible and may split into small groups or merge into large clans, depending on resource availability (Wittemyer et al., 2005; Couzin, 2006; Vance et al., 2009). The patchy distribution of food resources in savanna ecosystems and elephants’ bulk forage requirements make them prone to intraspecific and interspecific competition (Wittemyer et al., 2005). Thus, where plant biomass is low, like in the dry season and in the arid-eutrophic savannas in all seasons, elephants live in small groups to minimize the cost of competing for forage within the group (Vance et al., 2009). Moreover, the small and medium-sized species of herbivores in the arid-eutrophic savannas outcompete the larger herbivores by feeding selectively on the high-quality plant parts (Murray and Illius, 2000; Skarpe et al., 2014b). Therefore, differences in plant biomass and herbivores between savannas are expected to influence the feeding and reproductive output of female elephants. Grouping patterns of male elephants are also driven by primary productivity because males are larger than females, thus, need larger quantities of forage (Stokke and du Toit, 2000; Shannon et al., 2006).

Female elephants start reproducing at > 10 years of age and have a gestation time of 22 months (Gough and Kerley, 2006; Moss et al., 2011). The calving intervals differ with resource availability, where under good conditions females can have a calf every 3rd to 4th year (Moss, 2001; Foley and Faust, 2010; Wittemyer et al., 2013). The intervals tend to be much longer when resources are limited (Gough and Kerley, 2006; Freeman et al., 2009). The calving intervals and time of first calving affect population structure of elephants (Moss, 2001; Wittemyer et al., 2007a). The proportions of calves and young animals tend to be high in populations which females have short calving intervals (Armbruster and Lande, 1993; Wittemyer et al., 2007a). Thus, differences in resource availability between savannas drive demographic variations in terms of reproduction (Foley et al., 2001). While Mikumi has bulky forage of lower nutritional value, Serengeti has inherently nutritious forage which is also utilised by abundant and diverse community of small and medium size herbivores (Morrison et al., 2019). The influence of the savannas may be different in males because male elephants are bulk feeders and less selective (Shannon et al., 2006; Mramba and Mlingi, 2021).

Adult elephants do not have natural predators due to their big body size, but calves may be prey to lions (Panthera leo) (Loveridge et al., 2006; Power and Compion, 2009). However, humans are the main threat to adult elephants through poaching (Wittemyer et al., 2014; Wasser et al., 2015; Schlossberg et al., 2020a). Poaching disrupts the association patterns of elephants when members of a group are killed by poachers (Gobush et al., 2008; Archie and Chiyo, 2012). Females elephants in populations disturbed by poaching form small, less cohesive groups from genetically unrelated individuals (Archie et al., 2006). Stressed females tend to have long calving intervals (Foley et al., 2001; Gobush et al., 2008).

The aim of this study was to determine the size/age structure, group size, and habitat utilisation by elephants in Serengeti and Mikumi National parks, in Tanzania (hereafter Serengeti and Mikumi respectively). The savannas are considered eutrophic and dystrophic respectively (Bell, 1982; Halsdorf, 2011; Vedeld et al., 2012; Goldenberg et al., 2018). I predicted larger family and bachelor groups in Mikumi than in Serengeti due to larger plant biomass production and less interspecific competition in Mikumi. I predicted the elephants to occur and form larger groups in closed habitats than in the open habitats in both sites because elephants browse during the dry season, when this study was conducted. I also predicted Mikumi elephants to have shorter calving intervals and earlier first calving due to food resource availability, and hence a larger proportion of young elephants in Mikumi than the Serengeti.

2.1. Study sites

The study was conducted in Serengeti National Park (14,763 km²) in northern Tanzania and Mikumi National Park (3230 km²) in central Tanzania (Fig. 1).

The soils of Serengeti are largely nutrient rich ash deposits from the volcanoes on the Ngorongoro Highlands (Anderson et al., 2008; Rugemalila et al., 2016). The soils support savannas and woodlands with nitrogen-rich Senegalia spp. and Vachellia spp., as well as nitrogen-rich grasses and sedges in the central and western parts of the park (Rugemalila et al., 2016). The park has a species- and individual rich community of medium-sized grazers dominated by the blue wildebeest, Connochaetes taurinus, plains zebra, Equus quagga, gazelles, Gazella spp, and mixed feeders such as impala, Aepyceros melampus, as well as elephants (Sinclair et al., 2007; Rugemalila et al., 2016). Intense consumption of the forage by the small and medium sized herbivores reduces the standing plant biomass available for elephants (Morrison et al., 2019). The elephant population density in the central region of the park was estimated to be about 0.04 animals km^− 2 in 2013 (Rugemalila et al., 2016). Rainfall is seasonal and bimodal with short rains falling from November to December and long rains from March to May. Most areas, including the central region where this study was conducted receive about 600–800 mm rainfall per year (Sinclair et al., 2007).

Mikumi has nutrient poor sandy soils except the Mkata flood plain, which has black cotton soils (Backéus et al., 2006). The poor sand soils support unpalatable miombo wood species, which are dominated by Julbernadia globiflora and Brachystegia spp. (Backéus et al., 2006). These tree species are low in nitrogen and are defended against herbivory with carbon-based secondary compounds (Wigley et al., 2018). The small area of fertile flood plain have long grasses dominated by thatch grass Hyparrhenia rufa, scattered trees of Vachellia spp. and Senegalia spp., which are comparatively rich in nitrogen (Backéus et al., 2006). The fauna of Mikumi is dominated by large-bodied species such as elephant and buffalo, Syncerus caffer, and fewer species of small herbivores in the flood plain dominated by impala (TAWIRI, 2019). Plant biomass is comparatively larger than Serengeti and utilised by fewer herbivore species (TAWIRI, 2019). The elephant population density in the park was estimated to be about 0.25 elephants km^− 2 in 2018 (TAWIRI, 2019). There is one long rainy season, from November to May, peaking around April with annual rainfall ranging geographically from 750 to 850 mm per year (Vedeld et al., 2012).

2.2. Data collection

Data were collected in 2014, from mid-August to mid-September in Serengeti, and from mid-September to mid-October in Mikumi, that were dry seasons in both parks. I used 9 roads transects in Serengeti and 11 in Mikumi (Fig. 1). The length of the road transects in Serengeti ranged from 26 km to about 60 km, with an average length of 39 km ± 13 SD. In Mikumi, the road transects ranged from 10 to 70 km, with an average length of 40 km ± 16 SD. I drove a car on the road transects and make observations of elephants from 7:00 AM to 5:00 PM, six days per week. When elephants were sighted, the car was stopped for data recording. Group type (bachelor or family), group size, age composition and habitat type (open and closed) were determined through direct observations. Closed habitats were the areas with trees as dominant vegetation and open habitat were areas with scattered trees. Binoculars were used where elephants were located beyond 50 m from the car. Elephants were classified into different age classes through visual assessments, by comparing the shoulder heights of young elephants with the height of mature females as described by Moss (1996). The elephants that the top of their shoulder reached up to the area above the armpit of mature females were classified as 0–4 years old. Elephants that their body size was about half the size of adult females were classified as 5–9 years old. Those with body size reaching about three quarters of the size of adult females and with thin tusks were classified as 10–15 years old. Elephant groups were identified based on key individuals such as tuskless individuals, matriarchies, very large males and individuals with unique features such as damaged tusks and skin. To minimise the chance of sighting same groups, observations were made once per transect, and no observations were made in the same transect during the return trip.

Secondary data for elephant mortality were collected from wildlife censuses (Mduma et al., 2014; TAWIRI, 2019) in order to consider the influence of mortality rates on elephant group size, type, composition. Relative mortality (carcass ratio) was computed as the number of dead elephants / (number of dead + live elephants) (Schlossberg et al., 2020b).

2.3. Data analysis

Chi-square tests were used to compare the percentage of bachelor and family groups encountered in Serengeti and Mikumi.

The size of family groups between the sites was analysed by Generalised Linear Model (GLM) with a standard specification of the quasi-Poisson family. Evaluation of the model was done using the dispersion parameter. One of the assumptions of the Poisson distribution is that the mean of the data equals to the variance (Zuur et al., 2009). Over- or under-dispersion happens where the variance is larger or smaller than the mean, indicated by an over-dispersion parameter > 2. The dispersion parameter of the model was > 2, thus the quasi-Poisson model was adopted to accommodate the over-dispersion.

Proportions of animals of different age classes were calculated and compared between the sites. The proportional data comprised the values 0 where a certain age class was absent in the group and 1 where all animals in the group were above 15 years. Thus, a zero-one inflated model was adopted. I used GAMLSS (Generalized Additive Model for Location, Scale and Shape) model with beta-inflated distribution (BEINF) which accommodates both 0 and 1 values of proportion data (Ospina and Ferrari, 2012; Rigby et al., 2019). The road transects were specified as a random variable in the model. The analyses were done in R version 4.0.0 (R Core Team, 2020).

I predicted family and bachelor groups to be larger in Mikumi than in Serengeti. However, contrary to my prediction, the family groups were significantly larger in Serengeti than in Mikumi (Table 1, Fig. 2). The mean size of the family groups in Serengeti was 13.9 animals (95% CI, 12.0-15.8) while in Mikumi was 7.4 animals (95% CI, 6.5–8.3). However, the bachelor groups did not differ significantly between the sites (p > 0.05). The mean size of bachelor groups in Serengeti was 1.7 animals (95% CI, 1.1–2.1) while in Mikumi it was 1.4 animals (95% CI, 1.0-1.8). One hundred and one observations were made of family groups and 31 observations of bachelor groups in Serengeti, which is equivalent to 77% and 23% respectively of all observations in the site. In contrast, 87 observations of family groups and 9 observations of bachelor groups were made in Mikumi, which is equivalent to 91% and 9% respectively of all observations in the site. The difference in the percentage of bachelor and family groups between the sites was statistically significant (chi² = 6.70, df = 1, p = 0.009), with Mikumi having fewer bachelor groups than the Serengeti.

In addition, I predicted elephants to form larger family groups in closed habitats in all sites due to availability of trees which are the main source of food for elephants during the dry season. However, the main effect of habitat on groups size was not significant (Table 1), but the interaction effect between habitat and site on the size of the family groups was significant (Table 1). The family groups were larger in open habitats compared to closed habitats in Mikumi while in Serengeti they were larger in closed habitats compared to open habitats (Fig. 3). Forty eight percent of all family groups in Serengeti were sighted in open habitats while 52% were sighted in closed habitats. In contrast, 83% of the family groups in Mikumi were sighted in the open habitats while 17% were sighted in closed habitats. The difference in habitat selection between the sites was statistically significant (chi² = 25.4, df = 1, p < 0.001), where more groups of elephants were observed in open habitats in Mikumi compared to Serengeti.

Table 1

Comparison of the size of the family groups between the sites (Serengeti and Mikumi) and the habitats (closed and open).
Dependent variable	Expanatory varables	Coefficients	St. error	z-Values	p-Value
Group size	Intercept	1.813	0.163	11.093	< 0.001
	Serengeti	0.909	0.180	5.047	< 0.001
	Open habitat	0.230	0.178	1.291	0.196
	Serengeti*open habitat	-0.422	0.210	-2.011	0.044

I further predicted a larger proportion of young elephants in Mikumi than in Serengeti. However, contrary to the predictions, the Serengeti population had a larger proportion of young elephants aged 0–15 years, while the Mikumi population had a larger proportion of elephants above 15 years old (Fig. 4).The difference in age composition of elephants in the family groups between the sites was significant (Table 2).

Table 2

Comparison of elephant age classes (0–4 years, 5–9 years, 10–15 years and above 15 years) between the sites.
Dependent variable	Explanatory variables	Coefficients	St. error	t-Values	p-Value
Proportion of animals in a group	Intercept	0.426	0.046	9.160	< 0.001
	Serengeti* 0–4 yrs	0.753	0.111	6.905	< 0.001
	Serengeti* 5–9 yrs	0.648	0.101	5.587	0.001
	Serengeti * 10–15 yrs	0.679	0.105	6.449	0.008

The study shows differences in grouping behaviour and age structure of elephants between the sites, but opposite to the predictions. The Serengeti elephants formed larger family groups and had higher proportion of young elephants than Mikumi, perhaps because female and young elephants have high nutrient requirements that are supported in Serengeti. The grouping behaviour of bachelor males did not differ between the sites, although Serengeti seemed to have more bachelor groups than Mikumi.

Group living causes intraspecific competition for forage, which might be true in Serengeti, but should be less in Mikumi due to the larger plant biomass in the park. Mikumi is regarded as a favourable habitat for large herbivores that need large quantities of forage and tolerate low quality forage (Tsalyuk et al., 2019). In addition, the low abundance and diversity of other herbivores in Mikumi should reduce interspecific competition. All these factors were predicted to promote group cohesion in Mikumi. However, the elephants in Mikumi occur mostly in the open Mkata flood plain, avoiding the miombo woodland (TAWIRI, 2019). The plain offers high quality forage due to alluvial soils, but it is also where most of the wildlife are located (TAWIRI, 2019). Forage quality is an important nutritional factor in female elephants due to their higher nutritional requirements compared to males (Stokke and du Toit, 2000; Shannon et al., 2006).

Mikumi has a higher density of elephants than Serengeti (Rugemalila et al., 2016; TAWIRI, 2019). High population density increases intraspecific competition for resources and have shown to influence habitat selection by female elephants (Owen-Smith et al., 2006; Robson and Van Aarde, 2018). At a low density, animals select the best habitat which offers quality and abundant forage, and form large groups (Robson and Van Aarde, 2018).

Furthermore, poor food resources have a direct impact on reproduction in female elephants by decreasing production of hormones that regulate reproduction, resulting in a decrease in conception rates (Wittemyer et al., 2007b; Woolley et al., 2009). It seems that, the high quality forage in Serengeti meet the reproductive requirements of female elephants, thus promote reproductive efficiency which is indicated by the large proportion of young elephants aged 0–15 years. The importance of forage quality on reproductive efficiency of female elephants was demonstrated by Wittemyer et al.(2007a), (2007b) and (Woolley et al., 2009).

Male elephants need larger quantities of forage compared to females due to their larger body size (Stokke and du Toit, 2000; Shannon et al., 2006), thus are affected more by forage quantity than quality. Chiyo et al. (2014) found large bachelor groups in areas with high primary productivity, indicating that forage abundance influences grouping behaviour of male elephants. Apart from nutrition, the social behaviour and grouping patterns of male elephants are also driven by mating opportunities (Evans and Harris, 2008; Goldenberg et al., 2014). The Mikumi population appears to have fewer males although I counted males in bachelor groups only, meaning that the numbers are an underestimation. Mikumi population was estimated to have only one breeding-age bull to every 20 breeding-age females which was lower compared to other protected areas in the Tanzania (TAWIRI, 2010). This indicates that there might be multiple factors influencing the population.

Wood vegetation are the major source of forage for elephants during the dry season when they switch from a grass-dominated diet to a browse-dominated diet (Owen-Smith et al., 2006; Shannon et al., 2013). However, elephants should deal with secondary metabolites of trees, which influence the dietary switch differently between savannas (Codron et al., 2006; Kos et al., 2012). Despite being generalist feeders, elephants select high quality forage when available, and seem to avoid secondary metabolites (Jachmann and Bell, 1985; Owen-Smith and Chafota, 2012). The effect of secondary metabolites is higher in females, thus they tend to select habitats and tree species with low secondary metabolites (Stokke and du Toit, 2000; Stokke and du Toit, 2002; Shannon et al., 2006). I expected elephants to occur in wooded habitats during the dry season in all parks, indicating a switch to browsing. However, the family groups occurred equally in open and closed habitat in Serengeti, but in Mikumi occurred mostly in the flood plains. This indicates that, the Serengeti elephants switched to browsing, while the Mikumi didn’t switch, probably avoiding the unpalatable miombo species. A feeding study by Mramba et al. (2019) found that, Mikumi elephants grazed throughout the dry season, while Serengeti elephants switched to browsing.

Other factors that influence elephant populations are poaching and availability of drinking water. Poaching influence grouping behaviour, reproduction and habitat selection by elephants (De Boer et al., 2005; Gobush et al., 2008; Jones et al., 2018; Mkuburo et al., 2020). Serengeti and Mikumi differ in the level of poaching (Gobush et al., 2008; Jones et al., 2018; TAWIRI, 2019). The 2018 elephant census estimated a carcass ratio of 17% in Mikumi (TAWIRI, 2019) compared to 2.5% in Serengeti (Mduma et al., 2014), which was linked to poaching. A large proportion of the carcases in Mikumi were located in the wooded habitats, thus elephants might avoid these areas. Water is vital resource in elephant populations (Woolley et al., 2009; Chamaillé-Jammes et al., 2013). Serengeti is drained by the Mara River and its tributaries which flow westward to lake Victoria. Although the river flow decreases during the dry season, the animals drink from stagnant pools along the rivers (Kihwele et al., 2021). In contrast, Mikumi is drained by the Mkata river which is seasonal (Senzota and Mtahko, 1990). Animals drink from artificial water points during the dry season. The variation in dry season availability of water between the sites may influence reproduction, grouping behaviour and habitat selection.

The study shows differences in grouping behaviour of female elephants between the sites, but not in bachelor males. The Serengeti population had higher proportion of young elephants compared to Mikumi. Female elephants are more affected by forage quality due to their reproductive demands and smaller body size than males. While Mikumi offers large plant biomass which is required by large herbivores, the quality of the forage may not meet nutritional demands of the females, thus reducing reproduction. The female elephants benefit from group living through collective knowledge and caring of calves which increasing survival chance of the calves. Poaching seems to affect the Mikumi population by confining the elephants in safe habitats close to the park headquarters. The differences between are obvious, however, broad studies that will involve more savannas are recommended to explore behaviour and demography of elephants.

The study compare social behaviour and demography of elephants in eutrophic and dystrophic savannas. Only one of each savanna type was studied due to limited financial resources. Consequently, some factors which are not directly related to the savanna categories such as surface water availability and poaching might also have influenced the results. In addition, the study was conducted for short time within a single year and in the dry season, thus factors specific to the year of study and the season might have influenced the results. A study that will involve more sites per savanna category and account for interacting factors will increase the knowledge on behaviour and demography of elephants in these contrasting savannas.

Competing Interests

The author declares no conflict of interest.

Ethics approval

The permission to conduct the study was offered by Tanzania Wildlife Research Institute, where a permit letter with reference number TWRI/RG/22/VOL. 39/88/97 was offered.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Availability of data

The data for this study are available from the author upon reasonable request.

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Age structure and grouping behaviour of elephants in Serengeti and Mikumi National Parks in Tanzania.

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1.0. Introduction

2.0. Materials And Methods

2.1. Study sites

2.2. Data collection

2.3. Data analysis

3.0. Results

4.0. Discussion

6.0. Limitations Of The Study

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