The effect of habitat type on population distribution and abundance of Rothschild’s Giraffe (Giraffa camelopardalis rothschildi) in Ruma National Park and Mwea National Reserve in Kenya

The Rothschild’s giraffe is currently listed as vulnerable by the International Union for Conservation of Nature (IUCN). This is attributed to the loss of habitat due to human activities. This study examined the effect of habitat type on population structure and distribution of Rothschild’s giraffe in Ruma National Park (RNP) and Mwea National Reserve (MNR) in Kenya. The study employed road transects to collect data on the number, age class and sex distribution in three habitat types, open, medium and closed. Data was collected along three road transects of equal lengths measuring 14.2 km in each site (RNP and MNR) for comparison. A driving speed of 20 km per hour was maintained along each transect for standardization of survey effort and a maximum giraffe detection rate. Photographic capture of the coat patterns of the right side of all the giraffes sighted within 500 m from the transect was done for identification of age classes. The field visits were replicated 12 times for each transect giving 36 replications for each site spread equally through wet and dry seasons from March 2017 to November 2018. The effect of habitat type on population structure and distribution was analysed using ANOVA and Tukey HSD to test for significant differences. T-test was used to compare the mean population size of giraffe across the wet and dry seasons. Coat pattern analysis for age class identification was done using WildID software. The findings indicated that MNR had more males to females compared to RNP that registered more females and calves. Habitat type had a significant effect on the distribution of giraffes. The giraffe population showed a preference for medium habitat types. The findings are key for the management of habitat quality for giraffe populations at the interface where conservation areas overlap with human land use.

the management of habitat quality for giraffe populations at the interface where conservation areas 21 overlap with human land use. 22 Keywords: Rothschild's giraffe, population distribution, Giraffe conservation,23 24 INTRODUCTION 25 Africa serves as the cradle of the three giraffe sub-species as well as their origin. The observed decline 26 in the giraffe population is consistent within the continent and across the world. Various giraffe sub-27 species are currently occurring in twenty one countries across Sub-Saharan Africa. These countries 28 include Niger, down to Central, East and South Africa. This is made possible by their versatility in 29 nature enabling them to survive and thrive in areas with minimal tree cover (1). According to (2) giraffes 30 are extant in Cameroon, Chad, Botswana, Congo, Kenya,Ethiopia,Mozambique,Zambia,Zimbabwe,31 Uganda, and the Central Republic of Africa, Namibia, Niger, South Africa, Somalia, Tanzania, Angola 32 and Sothern Sudan. Giraffes are believed to be extinct in many countries to include; Guinea, Mauritania, 33 Eritrea, Senegal and Nigeria. The main threats facing the giraffe population have been sighted to be 34 habitat loss and land fragmentation (3). East Africa and Kenya specifically remain home to three 35 subspecies of giraffes; Maasai giraffe (Giraffa camelopardalis tipplekirschi), Rothschild's giraffe 36 (Giraffa carmelopardalis rothschildi) and Reticulated giraffe (Giraffa carmelopardalis reticulate ) (4-37 6). Home ranges for giraffes often overlap and they vary across Africa and this is influenced by several 38 environmental factors including, type of habitat and the amount of rainfall received, availability and 39 quality of forage, herbivore verse vis predator density, as well as human influences including poaching 40 and populations growth (7,8). 41 The Rothschild's giraffe was first described by Sir Walter Rothschild in the 18 th century, by then, these 42 giraffes were ranging feely and abundant across Kenya, Uganda and Sudan. In the late 1970s and early 43 1980s, Rothschild's giraffes were relocated from Soi Ranch in the Rift Valley of Kenya to Ruma 44 National Park, Nakuru National Park and later to Mwea National Reserve due to increasing human 45 activities and settlements (9). According to (2), giraffe's calves are usually preyed on by lions within 46 the early years of their life, in a study conducted in Lake Nakuru National Park, and this impacts 47 high rate of human population increase which eventually needed areas to settle and cultivate for their 57 basic livelihood needs (15). Due to the increasing need for agricultural settlement land and land 58 conversion to privately owned cattle ranches, land fragmentation became so high, gradually increasing 59 the giraffe's vulnerability (5,16). By the year 2010, Rothschild's giraffe population in the wild was less 60 than 670 individuals (10). Over 500 of these giraffes were found in Kenya hence making the country 61 an important stakeholder in the conservation and protection of the subspecies and its habitat (4). In June 62 2010, the IUCN declared the Rothschild's giraffe subspecies as endangered (17). 63 Rothschild's giraffe is historically known to have inhabited areas within eastern parts of Uganda and 64 Southern parts of Sudan and some areas in the Rift valley in Kenya. However, this sub-species was 65 eventually displaced from the original habitat due to human encroachment (2). Giraffes relate positively 66 to arid and semi-arid habitats due to their browsing behaviour. However, research shows that their 67 productivity is higher in humid environments rich in vegetative cover (18). Giraffes mostly feed on 68 leaves, flowers, twigs and fruits, therefore, shaping the vegetation within the savannah ecosystems (19). 69 Wooded grassland, which are rich ecosystems for their habitation are threatened by human 70 anthropogenic factors that include forest fires, agriculture & habitat degradation (13). 71 In Kenya, Rothschild's giraffes inhabited part of the Rift Valley on a land that was known as Soy Ranch 72 or Soi Ranch which was an 18,000 acre Ranch before they were translocated to Ruma National Park 73 and Lake Nakuru National Park in the late 1970s and early 1980s (20) for safety, due to human 74 encroachment and settlement. Currently, in Kenya and Uganda, Rothschild's giraffe numbers are 75 estimated to be 1,671 individuals (14). Giraffes cover long distances in search of forage and mates, this 76 has gradually increased the conflict between man and the giraffes as the demand for agricultural land 77 increased and vast lands fragmented for infrastructure development and settlement, consequently 78 reducing giraffe feeding range would negatively affect their breeding (21,22). Giraffes are megafaunas 79 that browse on a variety of plants across their feeding ranges, mostly these ranges are usually replaced 80 by crop farms which in turn reduce the variety of browse for the giraffes (19). In Kenya, they are faced 81 with many extrinsic threat factors including; habitat loss, poaching, climate change, infrastructure 82 development, inbreeding due to population isolation and intrinsic factors; loss of migration corridors, 83 dietary complications and interspecific competition as well as diseases, that lead to reduced carrying 84 capacity (23). Historically, Rothschild's giraffes inhabited the Western parts of Kenya, but all known 85 wild populations were extremely reduced mainly due to agricultural developments (14,23). type, and sex were recorded. Photographic capture of the right side of the giraffe coat pattern was taken 117 using a camera, Nikon Coolpix 900 for identification of the age class i.e., Adult, Sub-Adult and Calf. 118 The images of the giraffe coat patterns were matched to available reference coat patterns of the age 119 classes using WildID software (27). The field visits were replicated 12 times for each transect giving 120 36 replications for each site spread equally in wet and dry seasons for two annual years from March 121 The abundance of Rothschild's giraffe in RNP and MNR was calculated as the cumulative number of 125 individuals sighted along the transects. ANOVA and Tukey HSD post-hoc tests were used to test for 126 significant differences. Captured images were run through the Wild ID software to identify the age 127 classes of the individual giraffes recorded. Giraffe abundance was compared across age classes (adult, 128 calf and sub-adults), and three habitat types (closed, medium and open) in RNP and MNR. T-test was 129 used to compare abundance between dry and wet seasons and sex during the period of study. 130 Comparison of wildlife populations across habitat types to determine any difference in distribution due 131 to habitat type has also been applied by (28). Therefore, analysis was carried out separately for each 132 site; RNP and MNR to allow for comparison in R statistical software (29). 133

RESULTS 134
Giraffe population structure and distribution 135 The total number recorded during the period of study in RNP were 314 giraffes, 221 (70.4%) adults, 72 136 (22.9%) sub-adults and 21 (6.7%) calves while in MNR they were 56 giraffes, 38 (67.9%) adults, 8 137 (14.3%) sub-adults and 10 (17.9%). The distribution in the number of calves varied between the two 138 sites, (6.7% in RNP and 17.9% in MNR), RNP recorded a high number of females 181 (57.6%) while 139 MNR recorded 24 (42.9%) females which was fewer than that of the males in the same protected area. 140 MNR had a higher population of male giraffes (57.1%) as compared to the population of males in RNP 141 (42%) relative to the female population (Table 1). 142

The distribution of giraffe age classes and sex 147
There was a significant difference in the distribution of giraffes according to the age classes in MNR 148 (F-2.862, N = 482, DF2 P<0.05), with a slightly higher number of Sub-Adults. While in RNP 149 showed no significant difference in age class distribution (Fig 2). While more females were This is the Fig 2 legend: Boxplots comparing mean age classes of Rothschild's giraffe distribution in Ruma National Park (A) and Mwea National Reserve (B) use types; Adult, Calf and Adult.

Effect of habitat type on giraffe population distribution 153
Habitat type had a highly significant effect on the distribution of giraffes in Ruma, (F-106.2, N = 1723, 154 DF2 P<0.001) and significant effect in MNR, (F-9.939, n=482, DF2 P<0.05). In RNP a significant 155 difference was noted in all habitat types with medium habitat having high numbers followed by open 156 then closed habitat. In MNR a significant difference was established between open and closed habitats 157 and no difference between the pairs medium and closed, and open and medium (Fig 3). Giraffes are generally regarded as capital breeders and therefore they mostly rely on accumulated body 178 reserve to satisfy the energy needs for reproduction as opposed to income breeders that usually meet indication for the high numbers of giraffes as opposed to MNR. Predation is one of the main causes of 182 juvenile mortality in any given population in the wild (31,32), and this could be the case for MNR, 183 however, predation is also a component of seasonal variation in juveniles and MNR is not an exception. 184 It is expected that seasonal cases on reserve encroachment by the community are lower during the dry 185 season, leopards being the main predators on giraffe calves in this Reserve. The presence of predators 186 in any habitat would also result to a reduced reproduction success hence affecting the population growth 187 of a species (14,17). 188 According to (33,34), in the wild giraffes exhibit social patterns that are characterised by changes in 189 groups composition, where females are more in numbers than males being one aspect that makes a 190 heard healthy for breeding (35) where more females were recorded. Nonetheless, there is a biological trend that favour some female 203 giraffes unlike the male giraffes in the lower altitudes compared to higher altitudes (38,39), hence the 204 higher number of females in RNP than MNR. Therefore, the biological trend could be favouring the 205 giraffe population in RNP, which is at the lower altitude 206

Effect of habitat type on giraffe population distribution 207
In MNR, a high number of giraffes were recorded in medium habitats and low in closed habitats. This 208 was an isolated case because MNR exemplifies more of the closed habitat within its ecosystem, hence 209 no significant difference in the giraffe's distribution in the Reserve. In RNP, giraffes preferred medium 210 habitats, due to factors such as predation, competition and resource quality (40). Giraffe distribution in 211 both medium and closed habitats was the same hence similar utilization of the habitats. This supports 212 previous studies by (41,42) on ungulate species that showed that when temporal variation in adult 213 survival is low, calf survival typically becomes the most important determinant of population growth 214 and quality browse and it's availability for the young (40). Closed habitats recorded the least numbers 217 of giraffes, these areas were dominated by males and very few females, calves and sub-adults. This 218 concurs with (44), that giraffes inhabit dry, semi-arid and sub-tropical savannah environments that vary 219 from open to closed habitats, but they avoid forest habitats. The reason for this would be predation and 220 females keeping the calves away from threats or even competition from other species (45). Giraffes 221 were recorded to invade farms and this heightened the human-wildlife conflict in both RNP and MNR 222 communities, hence in reiteration the presence of human-oriented threats such as snaring and hunting 223 being propagated towards these giraffes in both RNP and MNR (45). 224

Effect of seasonality on giraffe population distribution 225
In RNP more giraffes were recorded in the three habitats during the dry season compared to the few 226 numbers during the wet season. This could be attributed to the park floods during the wet season hence 227 the giraffes stayed away from the low lying areas and instead remained on the higher grounds during 228 the wet season resulting in few numbers recorded during this period (40). This is contrary to what was 229 observed in MNR, with the reserve being well-drained, more giraffes were recorded during the rainy 230 season as in the savannah woodland habitat as opposed to during the dry season. This could be due to 231 forage availability or choice of forage during that particular period (46). 232

CONCLUSION 233
The low giraffe population with an imbalance in population structure in Mwea National Reserved could 234 be largely be attributed to risk factors relating to predation and human encroachment. Habitat type had 235 a significant effect on the distribution of giraffes. The giraffe population showed a preference for 236 medium habitat types characterised by mixed habitat structure including savannah and broken bushes.