Even though over many years the IUCN has considered the African buffalo and waterbuck and abundant species in Africa with no conservation concern, the situation is rapidly changing. Using aerial counts in wet and dry season in 2010 and 2013, this study assessed the trend, population status and distribution of the African buffalo and common waterbuck in the Northern Tanzania and Southern Kenya borderland. Both species were rare in the borderland, with the Amboseli region had the highest number of buffalo (241.5 ± 29.9), followed by Magadi/Namanga (58.0 ± 22.0), West Kilimanjaro (38.8 ± 34.9), and lastly Lake Natron (14.5 ± 9.0) areas. In terms of density, Amboseli also led with 0.03 ± 0.00 (buffalo per km 2), but rest had similar densities of 0.01 ± 0.00 buffalo per km 2. In terms of percent changes in buffalo, Amboseli area had a positive increase (+10.59 ± 27.71), but with a negative growth of -17.12 in the dry season. All other changes in all locations had negative (decline) buffalo numbers over time. For waterbuck numbers, Amboseli area also led with 12.3 ± 3.9 waterbuck), followed by Magadi/Namanga (10.3 ± 3.7.0), Lake Natron (3.8 ± 3.4), and lastly West Kilimanjaro (0.5 ± 0.5) areas. In terms of waterbuck density, they were low and less than 0.00 ± 0.00 per km 2. For percent changes in waterbuck numbers, Magadi/Namanga had higher positive change (+458.33 ± 291.67), but all other locations had negative (decline) changes with the worst being West Kilimanjaro and Lake Natron areas. Further, buffalo number was dependent (p = 0.008) on the season, with numbers being higher in the wet season than dry season. For waterbuck, numbers were independent (p = 0.72) of the season, with numbers being similar across seasons. The findings of this study showed that both species were negatively affected by drought. We recommend a constant joint monitoring program between Kenya and Tanzania, and jointly combat poaching, habitat fragmentation and encroachment to build viable populations in the borderland.
As one of the most widespread African ungulates, African buffalo is found throughout most of Africa south of the Sahara [
The African buffalo is active throughout the day, spending 18 hours per day moving and foraging [
African buffalo lives in large herds containing 50 to 500 animals [
African buffaloes are notable for their apparent altruism. Females appear to exhibit some sort of “voting behavior”. During resting time, the females will stand up, shuffle around, and sit back down again. They will sit in the direction they think they should move. After an hour of more shuffling, the females will travel in the direction they decide [
Buffaloes mate and give birth only during the rainy seasons. Birth peak takes place early in the season, while mating peaks later. A bull will closely guard a cow that comes into heat, while keeping other bulls at bay. This is difficult, as cows are quite evasive and attract many males to the scene. By the time a cow is in full estrus, only the most dominant bull in the herd/sub-herd is there. Cows first calve at five years of age, after a gestation period of 11.5 months. Newborn calves remain hidden in vegetation for the first few weeks while being nursed occasionally by the mother before joining the main herd. Older calves are held in the center of the herd for safety. The maternal bond between mother and calf lasts longer than in most bovids [
The African buffalo is a species of least concern according to the IUCN [
Apart from humans, buffalo is hunted by lions and crocodiles, which typically attack only old solitary animals and young calves [
Being a member of the big five game family [
The waterbuck (Kobus ellipsiprymnus) is a large antelope found widely in sub-Saharan Africa. It is placed in the genus Kobus of the family Bovidae. The thirteen subspecies are grouped under two varieties: the common or ellipsen waterbuck and the defassa waterbuck [
Waterbuck inhabit scrub and savanna areas along rivers, lakes and valleys. Due to their requirement for grasslands as well as water, the waterbuck have a sparse ecotone distribution. They are rather sedentary in nature. The waterbuck cannot tolerate dehydration in hot weather, and thus inhabits areas close to sources of water. Predominantly a grazer, the waterbuck is mostly found on grassland [
Though the defassa waterbuck have a much greater requirement for protein than the African buffalo and the Beisa Oryx, the waterbuck spend much lesser time on browsing (eating leaves, small shoots and fruits) in comparison to the other grazers [
The IUCN lists the waterbuck as being of Least Concerna ccording to the [
A gregarious animal, the waterbuck may form herds consisting of six to 30 individuals. The various groups are the nursery herds, bachelor herds and territorial males. Herd size increases in the dry season, whereas groups fragment in the wet months, probably under the influence of food availability. A few females may form spinster herds. Though females are seldom aggressive, minor tension may arise in herds [
Males start showing territorial behavior from the age of five years, but are most dominant from the age of six to nine. As soon as young males start developing horns (at around seven to nine months of age), they are chased out of the herd by territorial bulls. These males then form bachelor herds and may roam in female home ranges [
Marking of territories includes no elaborate rituals―dung and urine are occasionally dropped. Territorial males may use several kinds of display. In one type of display, the white patch on the throat and between the eyes is clearly revealed, and other displays can demonstrate the thickness of the neck [
While males become sexually mature at the age of six years, females reach maturity within two to three years. Females may conceive by the age of two-and-a-half years, and remain reproductive for another ten years [
This study examined the population status, trend and distribution of the African buffalo and common waterbuck populations in the Northern Tanzania and Southern Kenya borderland in the dry and wet season of 2010 and 2013. These findings are important in many ways including but not limited to helping the Kenya and Tanzania governments to formulate collaborative management and conservation of borderland wildlife resources. The dramatic buffalo and waterbuck population declines in the two countries calls for urgent, decisive and comprehensive and remedial interventions to protect the remaining populations and their habitats. In the long-term, this will enhance their population resilience to the intensifying droughts conditions and land use changes whilst contributing to the national economy and sustainable local livelihoods.
The overall objective of this research was to establish the current status of the African buffalo and common waterbuck population and its recovery after the severe 2007 and 2009 droughts in the Kenya-Tanzania borderland. The specific objectives were to:
Specifically, this study examined the following objectives:
1) Determine the population status and trend of buffalo and waterbuck in the Kenya-Tanzania borderland;
2) Determine the rate of population number and density growth (or decline) in ecosystems along the Kenya- Tanzania borderland;
3) Assess spatial-temporal distribution of buffalo and waterbuck in the Kenya-Tanzania borderland;
4) Make recommendations that will enhance monitoring and conservation of wildlife populations across the Kenya-Tanzania borderland.
The Amboseli-West Kilimanjaro and Magadi-Natron cross-border landscape, as comprises of various ecologically linked areas of Kenya and Tanzania, and is characterized by a high endowment of diverse wildlife species (
Amboseli region lies in the Southern part of Kenya, along the international border with Tanzania, and occupies an area of nearly 8797 km2 (
environment, with most of it lying in ecological zone VI, making unsuitable for crop farming unless under irrigation [
Historically, the Amboseli area was predominantly occupied by the Maasai people who depended on pastoralism to meet their livelihood needs [
Typical vegetation in the region is influenced by the ecological conditions which are arid to semi-arid [
This landscape comprises of; Meto, Torosei, Mbuko, Elangata Wuas, Olkiramatian, Lorngosua and Shompole ranches, which collectively cover about 5513 km2 (
Ewaso Ngiro is the only permanent river though there are several other seasonal rivers like the Namanga and Esokota which originate from Namanga and Meto hills. The other main seasonal river is the Ol Kejuado that originates from Ilemelepo hills to the north west of Ibisil town and drains into river Kiboko.
The diverse physical features have led to spatial-temporal variation vegetation communities, but generally, the dominant woody species include a variety of Acacia spp., Commiphora spp. and Balanites spp. Key grasses include; Chloris roxburgiana, Pennisetum stramenium, Pennisetum mezianum, Digitaria sp., Cynodon dactylon and Eragrostis sp. Rainfall is low, bimodal and highly variable, ranging between 400 - 600 mm, making pastoralism by the Maasai the most common land use [
The West Kilimanjaro covers an of nearly 3014 km2 within the Longido District of Arusha, Tanzania, and the northern extent of the area is the Tanzania-Kenya border from Namanga southeastward to Irkaswa (
The area comprises of a complex mosaic of diverse communities, extensive grazing lands, and large agricultural fields at lower elevations on Mt. Kilimanjaro. There are traditional, agro-pastoral Maasai communities that graze livestock and raise subsistence crops. The area has several Protected Areas (PAs) in its neighborhoods, mainly; Kilimanjaro N. P (755 km2) on the eastern boundary, Arusha N. P (137 km2) to the south, and Amboseli N. P (392 km2) in southern Kenya, 20 km north of the Tanzania-Kenya border. Other PAs in the West Kilimanjaro include; Longido Game Controlled Area (GCA) (1700 km2), and Ngasurai Open Area (544 km2) which provide important habitats for wildlife. Additionally, there are two private conservation areas, West Kilimanjaro Ranch (303 km2) and Endarakwai Ranch (44 km2).
Although the area varies in elevation (1230 to 1600 m), the predominant ecological zone is semi-arid savannah interspersed with woodlands. There are extensive agricultural fields along the lower, western flank of Mt. Kilimanjaro, and lowland forests within the boundary of Kilimanjaro NP. Rainfall is unpredictable, especially at lower elevations, and highly variable from year to year. The average annual rainfall in the semi-arid lower elevations is 341 mm/year [
This landscape covers an area of about 7047 km2, and lies west of the West Kilimanjaro area with its northern extent defined by the Tanzania-Kenya border (
For a many years since its creation, the Kenya Wildlife Service (KWS) has been undertaking total aerial counts of large herbivores using developed methods [
To improve the quality of data collected on the elephant population, both crew and planes were calibrated to aid in estimation of distance for subsequent calculation of observable strip width. Streamers were mounted on either side of the aircraft wings to create two strip categories, the inner and outer (
Calibration for observers entailed adjusting the angle of view of the streamers to correspond to 500 m and 250 m on the ground for a set altitude of 300 Ft AGL for the upper and lower streamer respectively. This was done by use of clinometers. The Rear Seat Observers (RSO’s) were each calibrated and observer specific and plane specific metrics for each calibration recorded according to an individual’s physique. The metrics comprised measurements from various reference points on the air craft such as low and high eye mark on the aircraft window, upper and lower streamer mark on wing strut and plane fuselage. In addition, Front Seat Observers (FSO’s) and pilots were also calibrated for the purpose of assisting the RSO’s to determine whether or not the counted animals are within the strip width.
For each calibration made, test flights were conducted at the set altitude for streamers (300 Ft AGL) to determine how well the streamers fitted to the desired strip width on the ground. This was achieved by creating a flight line at 500 m and 250 m from a very straight and long (5 km) section of a road. When the aircrafts flew on this line, the road was either 500 m or 250 m from the plane and this allowed for evaluation of the streamers. To asses inter observer variability in estimation and enhance species identification, all observers were independently subjected to count a portion of the same block with different species of known numbers in mock flights.
The target landscape was divided into blocks based on visible features from the aircraft like hills, ridges and rivers which helped the pilots to easily navigate during flight (
seat observers (FSOs) to navigate using GPS units. It also gave them ample time to make comprehensive ground observations, and an attempt was made to ensure the blocks were large enough (about 900 km2 each on average), and could be covered within a maximum duration of six hours per day. The enhance reliability of the data collected, the counting crew were trained on how to conduct aerial counts using mock test flights. Thus, different crews flew at different times but maintaining the same flight orientation so as to evaluate any inter observer variation in their ability to identify, detect, estimate and count wildlife species. They were also trained on use of voice recorders, GPS units and cameras, wildlife species identification, counting, estimation of herd sizes, data processing and handling. As noted by [
Counting of large herbivores was done in each block using a light aircraft which flew along East-West and North-South flight transects of 1 - 2 km width depending on the visibility on the ground and nature of the terrain (
In addition to elephant data, the flight observers noted and recorded human activities mainly vegetation clearing, livestock grazing, human settlements and infrastructure development. These were considered to represent key changes in the landscape which threatened its ecological integrity and elephant conservation.
Only data for the dry period of 2010 and 2013 were used so that comparisons between similar census zones and for wet and dry season could be compared. Tallies, percentages, means and standard errors for the data were calculated using standard mathematical and statistical methods [
Chi-square goodness of fit and chi-square cross-tabulations were done to establish differences and the association between ostrich numbers and ecosystem areas; periods after (2010) and post drought (2013); and seasons (wet and dry) using SPSS statistical software. Statistical tests were considered significant if type 1 error (alpha) was less than 5% (0.05) [
Since the census areas (for both wet and dry season) for 2010 and 2013 were similar, the total numbers, density and percentages (proportions) of each species of the large mammals seen were reliable measures for comparison.
African (cape) buffalo (Syncerus caffer) was well represented in all the landscapes during the 2010 and 2013 censuses. Only within the swamps of Amboseli were the majority seen, and a few more in the Lake Natron and Lake Magadi marshes. Amboseli and its surrounding group ranches had the highest number of African buffalo (
In terms of the number composition of buffalo in each area of the borderland (
Location | Year | Season | Census area (km2) | Buffalo numbers | Buffalo density (per km2) | Proportion (%) buffalo numbers in the borderland |
---|---|---|---|---|---|---|
Amboseli area | 2010 | Wet | 8797.00 | 235 | 0.03 | 70.36 |
Dry | 8797.00 | 222 | 0.03 | 69.81 | ||
2013 | Wet | 9214.44 | 325 | 0.04 | 56.52 | |
Dry | 9214.44 | 184 | 0.02 | 100.00 | ||
Overall (mean ± SE) | - | 241.5 ± 29.9 | 0.03 ± 0.00 | 74.17 ± 9.18 | ||
Magadi/Namanga Area | 2010 | Wet | 5513.00 | 62 | 0.01 | 18.56 |
Dry | 5513.00 | 63 | 0.01 | 19.81 | ||
2013 | Wet | 6348.32 | 107 | 0.02 | 18.61 | |
Dry | 63.48.32 | 0 | 0.00 | 0.00 | ||
Overall (mean ± SE) | - | 58.0 ± 22.0 | 0.01 ± 0.00 | 14.25 ± 4.76 | ||
West Kilimanjaro Area | 2010 | Wet | 3014.00 | 0 | 0.00 | 0.00 |
Dry | 3014.00 | 12 | 0.00 | 3.77 | ||
2013 | Wet | 3013.18 | 143 | 0.05 | 24.87 | |
Dry | 3013.18 | 0 | 0.00 | 0.00 | ||
Overall (mean ± SE) | - | 38.8 ± 34.9 | 0.01 ± 0.01 | 7.16 ± 5.97 | ||
Lake Natron Area | 2010 | Wet | 7047.00 | 37 | 0.01 | 11.08 |
Dry | 7047.00 | 21 | 0.00 | 6.60 | ||
2013 | Wet | 7047.26 | 0 | 0.00 | 0.00 | |
Dry | 7047.26 | 0 | 0.00 | 0.00 | ||
Overall (mean ± SE) | - | 14.5 ± 9.0 | 0.00 ± 0.00 | 4.42 ± 2.71 |
± 2.71%). For buffalo density, similar trend was maintained (
Considering (percent) changes in the density in each of the locations of the borderland between 2010 and 2013, Amboseli area had an overall positive buffalo density increase (+5.58 ± 26.45), but with a negative growth of −20.87 in the dry season hence the high variance in overall growth in buffalo density (
Location | Season | Buffalo density (per km2) (mean ± SE) | Buffalo % numbers in location (mean ± SE) | Change (%) in buffalo density over 3 years | Change (%) in buffalo proportion over the 3 years |
---|---|---|---|---|---|
Amboseli Area | Wet | 0.03 ± 0.00 | 63.44 ± 6.92 | +32.03 | +38.30 |
Dry | 0.02 ± 0.00 | 84.91 ± 15.09 | −20.87 | −17.12 | |
Overall | 0.03 ± 0.00 | 74.17 ± 9.18 | +5.58 ± 26.45 | +10.59 ± 27 | |
Magadi and Namanga Area | Wet | 0.01 ± 0.00 | 18.59 ± 0.02 | +49.87 | +72.58 |
Dry | 0.01 ± 0.01 | 9.91 ± 9.91 | −100.00 | −100.00 | |
Overall | 0.01 ± 0.00 | 14.25 ± 4.76 | −25.06 ± 74.94 | −13.71 ± 86.29 | |
West Kilimanjaro Area | Wet | 0.02 ± 0.02 | 12.43± 12.43 | No animals in wet season 2010 and dry season 2013. | No animals in wet season 2010 and dry season 2013. |
Dry | 0.00 ± 0.00 | 1.89 ± 1.89 | −100.00 | −100.00 | |
Overall | 0.01 ± 0.01 | 7.16 ± 5.97 | - | - | |
Lake Natron Area | Wet | 0.00 ± 0.00 | 5.54 ± 5.54 | −100.00 | −100.00 |
Dry | 0.02 ± 0.00 | 3.30 ± 3.30 | −100.00 | −100.00 | |
Overall | 0.00 ± 0.00 | 4.42 ± 2.71 | −100.00 ± 0.00 | −100.00 ± 0.00 |
changes in buffalo density in all locations in the borderland were negative (decline in buffalo density). The worst off in terms of this decline was Lake Natron area (−100.00 ± 0.00), followed by West Kilimanjaro area (−100.00 in dry season because there were no buffalo in the wet season of 2010 and dry season of 2013), and least decline for Magadi/Namanga area (−25.06 ± 74.94) which experienced a decline of −100.00 in the dry season buffalo density (
In terms of changes (percent) in the buffalo number composition of the locations in the borderland between 2010 and 2013, similar trend as in (percent) changes buffalo density was observed (
There were higher wet season changes in buffalo density and composition in Amboseli and West Kilimanjaro areas. However, dry season changes in density and composition of buffalo occurred in Lake Natron area only. The highest change differences in both density and composition occurred in Magadi, followed by Lake Natron and then Amboseli area. Decline (negative change) in buffalo density and composition occurred in Lake Natron and West Kilimanjaro areas in all seasons, but negative only in the dry season in Amboseli and Magadi (
Wet and dry season numbers of buffalo over time varied from with location in the borderland (
For West Kilimanjaro area in 2010, buffalo were only seen in the dry season and not in the wet season. However, in 2013, buffalo were only seen in the wet season and not in the dry season. For the pair of wet season, buffalo were only seen in 2013 implying an increase with time. But for the dry season, buffalo were seen only seen in the in 2010 implying a possible decline with time (
In terms relationships between Buffalo numbers in different locations (closer or further away from protected areas), influence of seasons on Buffalo numbers varied among the locations in the borderland (
The common waterbuck (Kobus ellipsiprymnus) was well represented in all the landscapes and ecosystems (protected areas and dispersal areas) along the Kenya-Tanzania borderland during the 2010 and 2013 censuses. Amboseli area had the highest number of common waterbuck (
Census location | Year | Season census done | Chi-square goodness of fit value | Conclusion | |
---|---|---|---|---|---|
Wet season | Dry season | ||||
Amboseli | 2010 | 235 | 222 | Χ2 = 0.37, df = 1, p = 0.54 | For 2010, wet season and dry season numbers were similar, with wet season being non-significantly higher. |
2013 | 325 | 184 | Χ2 = 39.06, df = 1, p < 0.001 | For 2013, wet season number was higher than the dry season number. | |
Chi-square value | Χ2 = 14.46, df = 1, p = 0.31 | Χ2 = 3.56, df = 1, p = 0.059 | For the set of wet season, and dry season, buffalo numbers were similar over time (with non-significant increase in wet season, but also non-significant decline in the dry season over time). | ||
Magadi | 2010 | 62 | 63 | Χ2 = 0.008, df = 1, p = 0.93 | For 2010, wet season and dry season numbers were similar. |
2013 | 107 | 0 | No statistical test necessary | For 2013, wet season number was higher than dry season number because there were no buffalo seen in dry season. | |
Chi-square value | Χ2 = 11.98, df = 1, p = 0.001 | No statistical test necessary. | For both sets of wet season, buffalo number in 2013 was higher than for 2010 (i.e. buffalo number increased with time for both seasons). This cannot be said for the dry season because there were no buffalo in 2013 meaning a possible decline. | ||
West Kilimanjaro | 2010 | 0 | 12 | No statistical test necessary | For 2010, buffalo were only seen in the dry season and not wet season. |
2013 | 143 | 0 | No statistical test necessary | For 2013, buffalo were only seen in the wet season but not in the dry season. | |
Chi-square value | No statistical test necessary. | No statistical test necessary. | For the pair of wet season, buffalo were only seen in 2013 implying an increase with time. But for the dry season, buffalo were seen only in the in 2010 implying a decline with time. | ||
Natron | 2010 | 37 | 21 | Χ2 = 4.41, df = 1, p = 0.036 | In 2010, the buffalo number in the wet season was higher than the dry season. |
2013 | 0 | 0 | No statistical test necessary | For 2013, there were no buffalo numbers in both wet and dry season. | |
Chi-square value | No statistical test necessary. | No statistical test necessary. | For both pairs of wet and dry season, buffalo were only seen in 2010 but not 2013, implying a possible decline with time for both seasons. |
Season of the year | Year | Location of census area | Chi-square cross tabulation value | Conclusion | |
---|---|---|---|---|---|
In or around protected areas | Away from protected areas | ||||
Wet season | 2010 (after drought) | 235 | 99 | Χ2 = 14.67, df = 1, p < 0.001 | In the wet season, buffalo number in locations was dependent of year, with numbers in both closer and further from protected areas increasing with time. |
2013 (post drought) | 468 | 107 | |||
Dry season | 2010 (after drought) | 234 | 84 | Χ2 = 58.37, df = 1, p < 0.001 | In the dry season, buffalo number in locations was dependent on year, with numbers in both closer and further from protected areas declining with time. |
2013 (post drought) | 184 | 0 | |||
Wet season | 703 | 206 | Χ2 = 6.96, df = 1, p = 0.008 | Generally, buffalo numbers in locations was dependent on the season, with numbers both closer and further away from protected areas being higher in the wet season than try season. | |
Dry season | 418 | 84 |
Location | Year | Season | Census area (km2) | Waterbuck numbers | Waterbuck density (per km2) | Proportion (%) waterbuck numbers in the borderland |
---|---|---|---|---|---|---|
Amboseli and surrounding group ranches | 2010 | Wet | 8797.00 | 18 | 0.00 | 50.00 |
Dry | 8797.00 | 17 | 0.00 | 73.91 | ||
2013 | Wet | 9214.44 | 13 | 0.00 | 43.33 | |
Dry | 9214.44 | 1 | 0.03 | 5.56 | ||
Overall (mean ± SE) | - | 12.3 ± 3.9 | 0.00 ± 0.00 | 43.20 ± 14.16 | ||
Magadi/Namanga Areas | 2010 | Wet | 5513.00 | 2 | 0.00 | 5.56 |
Dry | 5513.00 | 6 | 0.00 | 26.09 | ||
2013 | Wet | 6348.32 | 17 | 0.00 | 56.67 | |
Dry | 63.48.32 | 16 | 0.00 | 88.89 | ||
Overall (mean ± SE) | - | 10.3 ± 3.7 | 0.06 ± 0.03 | 44.30 ± 18.20 | ||
West Kilimanjaro Area | 2010 | Wet | 3014.00 | 2 | 0.00 | 5.56 |
Dry | 3014.00 | 0 | 0.00 | 0.00 | ||
2013 | Wet | 3013.18 | 0 | 0.00 | 0.00 | |
Dry | 3013.18 | 0 | 0.00 | 0.00 | ||
Overall (mean ± SE) | - | 0.5 ± 0.5 | 0.00 ± 0.00 | 1.39 ± 1.39 | ||
Lake Natron Area | 2010 | Wet | 7047.00 | 14 | 0.00 | 38.89 |
Dry | 7047.00 | 0 | 0.00 | 0.00 | ||
2013 | Wet | 7047.26 | 0 | 0.00 | 0.00 | |
Dry | 7047.26 | 1 | 0.00 | 5.56 | ||
Overall (mean ± SE) | - | 3.8 ± 3.4 | 0.00 ± 0.00 | 11.11 ± 9.35 |
In terms of the composition of common waterbuck in each area of the borderland (
Considering (percent) changes in the density between 2010 and 2013, Magadi/Namanga area had the highest positive average percent change (increase) in common waterbuck density (+384.87 ± 253.29) compared to other locations in the borderland (
There were more changes in waterbuck density and composition in the wet season in Magadi/Natron, West Kilimanjaro and Lake Natron areas, but more changes in the dry season in only Amboseli areas. The highest positive change differences in both density and composition were in Magadi/Namanga area. Amboseli, West Kilimanjaro and Lake Natron all had negative change in density and numbers of waterbuck, with more negative (decline) being in West Kilimanjaro and Lake Natron areas especially in the dry season (
Location | Season | Waterbuck density (per km2) (mean ± SE) | Waterbuck % numbers in location (mean ± SE) | Change (%) in waterbuck density over 3 years | Change (%) in waterbuck proportion over the 3 years |
---|---|---|---|---|---|
Amboseli Area | Wet | 0.00 ± 0.00 | 46.67 ± 3.33 | −31.05 | −27.78 |
Dry | 0.00 ± 0.00 | 39.73 ± 34.18 | −94.38 | −94.12 | |
Overall | 0.00 ± 0.00 | 43.20 ± 14.16 | −62.72 ± 31.67 | −60.95 ± 33.17 | |
Magadi and Namanga Areas | Wet | 0.00 ± 0.00 | 31.11 ± 25.56 | +638.16 | + 750.00 |
Dry | 0.00 ± 0.00 | 57.49 ± 31.40 | +131.58 | + 166.67 | |
Overall | 0.00 ± 0.00 | 44.30 ± 18.20 | +384.87 ± 253.29 | +458.33 ± 291.67 | |
West Kilimanjaro Area | Wet | 0.00 ± 0.00 | 2.78 ± 2.78 | −100.00 | −100.00 |
Dry | 0.00 ± 0.00 | 0.00 ± 0.00 | - | - | |
Overall | 0.00 ± 0.00 | 1.39 ± 1.39 | No waterbuck except 2 ones in wet season 2010. | No waterbuck except 2 ones in wet season 2010. | |
Lake Natron Area | Wet | 0.00 ± 0.00 | 19.44 ± 19.44 | −100.00 | −100.00 |
Dry | 0.00 ± 0.00 | 2.78 ± 2.78 | - | - | |
Overall | 0.00 ± 0.00 | 11.11 ± 9.35 | No waterbuck in dry season 2010 and wet season 2013. | No waterbuck in dry season 2010 and wet season 2013. |
For Amboseli area in 2010, wet season waterbuck number was similar (p = 87) to the dry season number. But for 2013, wet season waterbuck number was higher (p < 0.001) to the dry season number. For the set of wet season, waterbuck number for 2010 was similar (p = 0.37) to that of 2013 (i.e. a non-significant decline in number over time in wet season). But for the set of dry season, waterbuck number in 2010 was higher (p < 0.001) than for 2013 (i.e. waterbuck number was decreasing with time) for the Amboseli area (
Census location | Year | Season census done | Chi-square goodness of fit value | Conclusion | |
---|---|---|---|---|---|
Wet season | Dry season | ||||
Amboseli | 2010 | 18 | 17 | Χ2 = 0.29, df = 1, p = 0.87 | For 2010, wet season was similar to the dry season number. |
2013 | 13 | 1 | Χ2 = 10.29, df = 1, p < 0.001 | For 2013, wet season number was higher than the dry season number. | |
Chi-square value | Χ2 = 0.81, df = 1, p = 0.37 | Χ2 = 14.22, df = 1, p < 0.001 | For the set of wet season, waterbuck number for 2010 was similar to that of 2013 (i.e. a non-significant decline in number over time in wet season). But for the set of dry season, waterbuck number in 2010 was higher than for 2013 (i.e. waterbuck number was decreasing with time). | ||
Magadi | 2010 | 2 | 6 | Χ2 = 2.00, df = 1, p = 0.16 | For 2010, wet season number was similar to the dry season number, with non-significant more in the dry season. |
2013 | 17 | 16 | Χ2 = 0.30, df = 1, p = 0.86 | For 2013, wet season number was similar to dry season number. | |
Chi-square value | Χ2 = 11.84, df = 1, p < 0.001 | Χ2 = 4.55, df = 1, p = 0.033 | For the set of wet season, waterbuck numbers in 2010 was higher than for 2010 (i.e. waterbuck was increasing with time). Similarly, for the set of dry season, waterbuck number in 2013 was higher than for 2010 (i.e. waterbuck was also increasing in the dry season). | ||
West Kilimanjaro | 2010 | 2 | 0 | No test necessary. | Waterbucks seen only in the wet season of 2010 and not dry season of 2010. |
2013 | 0 | 0 | No test necessary. | No waterbuck seen in West Kilimanjaro in 2013. | |
Chi-square value | No test necessary. | No test necessary. | Waterbuck seen only in the wet season of 2010 and not in other census periods. | ||
Natron | 2010 | 14 | 0 | No test necessary. | For 2010, waterbuck was seen only in the wet season but not in the dry season. |
2013 | 0 | 1 | No test necessary. | For 2013, only one waterbuck was seen only in the dry season, but none in the wet season. | |
Chi-square value | No test necessary. | No test Necessary. | For the set of wet season, waterbuck was only seen in 2010 and not 2013, implying a decline. But in the set of dry season, only one waterbuck was seen in 2013 and not 2010, implying a re-colonization. |
in the Magadi/Namanga area. For the set of wet season, waterbuck numbers in 2010 was higher (p < 0.001) than for 2010 (i.e. waterbuck was increasing with time). Similarly, for the set of dry season, waterbuck number in 2013 was higher (p = 0.033) than for 2010 (i.e. waterbuck was also increasing in the dry season).
For West Kilimanjaro area in 2010, Waterbuck was seen only in the wet season of 2010 and not the dry season of 2010. Further, for the 2013 wet season, no waterbuck seen in West Kilimanjaro in the whole of 2013. For the set of wet and set of dry seasons, comparisons were not possible because only two waterbucks were seen in the wet season of 2010 and not in the dry season, and not in the entire 2013 censuses in West Kilimanjaro area (
In terms relationships between common waterbuck numbers in different locations (closer or further away from protected areas), influence of seasons on common waterbuck numbers varied among the locations in the borderland (
Season of the year | Year | Location of census area | Chi-square cross tabulation value | Conclusion | |
---|---|---|---|---|---|
In or around protected areas | Away from protected areas | ||||
Wet season | 2010 (after drought) | 20 | 16 | Χ2 = 0.10, df = 1, p = 0.32 | In the wet season, waterbuck number in locations was independent of year, with numbers in both closer and further from protected areas remaining similar with time. |
2013 (post drought) | 13 | 17 | |||
Dry season | 2010 (after drought) | 17 | 6 | Χ2 = 19.16, df = 1, p < 0.001 | In the dry season, waterbuck number in locations was dependent on year, with numbers near protected areas declining with time while those further away from protected areas increasing with time. |
2013 (post drought) | 1 | 17 | |||
Wet season | 33 | 33 | Χ2 = 0.13, df = 1, p = 0.72 | Generally, waterbuck numbers in locations was independent on the season, with numbers closer and further away from protected areas being similar across seasons. | |
Dry season | 18 | 23 |
was independent (cross-tabulations, p = 0.72) of the season, with numbers in all locations being similar across seasons. In terms of relationship with years, in the wet season, waterbuck number in locations near and further away from protected areas was independent (p = 0.32) of year, with numbers in both closer and further from protected areas remaining similar with time. But in the dry season, waterbuck number in locations was dependent (p < 0.001) on year, with numbers near protected areas declining with time while those further away from protected areas increasing with time (
The African buffalo and common waterbuck were poorly represented both in distribution and numbers in the borderland, and their population size is very low. The buffalo seem to be comparatively less abundant with about a majority of them are Amboseli and very few (less than fifty) in other areas. But common waterbuck were even more less, with most of the numbers less than ten in number in each of the locations. This is worrying because these species are very important grazers and prey in the African savannah ecology and these results highlight their decline. It is also instructive to note that whereas other species may easily be under-estimated in aerial counts because they are relatively small to see from the air (some gazelles, warthogs and most carnivores), and because of habitat cover (baboons and those who prefer thickets and bush), the African buffalo and waterbuck can clearly be seen from the air [
For the buffalo, Amboseli had the majority of the few numbers of buffalo (over 74%) and therefore remains the bedrock of viable buffalo populations in the borderland. However, buffalo were also found in all the locations of the borderland. This also highlights the potential and importance of other locations for supporting buffalo populations in the borderland. But more important is when you examine the rate of density and number changes over time and across seasons. Buffalo, only Amboseli had a small positive growth in density and numbers, but still had a decline (negative growth) in wet season. All other locations in the borderland had a negative growth in buffalo populations. This result reinforces the concern that the buffalo may actually be on its constant trend of decline and attention to reasons (drought mortality, retaliatory killings, declining water sources as climate change takes more tall) needs to be elaborated. This species is often sedentary and localized in ranging as buffalo herds maintain specific home ranges, so a decline in numbers cannot be attributed to drastic movements and immigration, but most likely on mortality. When the decline is in all the seasons and all the locations of the borderland, then this implies that buffalo may be becoming a locally threatened and endangered species in the borderland and urgent attention by conservationists need to be undertaken to highlight not only reasons for the decline, but remedial measures.
For both common waterbuck, both Magadi/Namanga area (with 44%) and Amboseli area (with 43%) had similar numbers and therefore both areas seemed to be critical as they contained the majority of the few remaining (about ten individuals each) of the species. This highlights the potential and importance of Magadi/Namanga area for supporting a good population of waterbuck in the borderland. The numbers in West Kilimanjaro and Natron will be wiped off unless there is immigration or rapid population recovery as the numbers are less than four in Lake Natron area and less than one in west Kilimanjaro. The waterbuck population in West Kilimanjaro is already practically locally extinct already. Looking at the changes in numbers and density of waterbuck over time, only Magadi/Namanga had a positive waterbuck population in density and numbers, but all other locations, including Amboseli area had negative (decline) change. This result reinforces the concern that waterbuck is already on its constant trend of decline as the population numbers are likely below viable population thresholds in the entire Kenya/Tanzania borderland. Therefore attention to reasons (drought mortality, retaliatory killings, declining water sources as climate change takes more tolls) needs to be urgently elaborated. Waterbuck are very sedentary and localized in ranging [
The African buffalo belongs to the tribe bovini with domestic cattle among other bovids ([
The Common waterbuck belongs to the tribe reduncini with reedbucks among other bovids. Ecologically, the for waterbuck, are the most water-dependent of all herbivores, and have even low tolerance of dehydration compared even to domestic animals. They are selective grazers, and that is why their distribution is limited to grasslands closer to water. Its preferred habitats are therefore grasslands and open woodlands closer to water sources in swamps or riverine areas [
Results showed that buffalo numbers in locations were dependent of season, and numbers were more in the wet season than dry season in both near and further away from protected areas across the wet and dry season. This is consistent with what is expected. It is expected that generally herbivore numbers will depend on season, and that numbers will increase in the wet than dry season. During the wet season, buffalo numbers are expected increase because more forage and water will be plentiful and competition with other herbivores will be less, as well as predation pressure on them declining due to plentiful other prey species availability [
However, animal numbers will always not thrive in wet season when there is more forage and water. Animal ecology, particularly foraging and habitat requirements may influence how animal numbers respond to wet and dry seasons over time. For Amboseli area showed that even though wet season waterbuck numbers were higher than dry season numbers, generally waterbuck was declining with time. For Amboseli area, buffalo wet season numbers were higher than dry season numbers than in dry season, but numbers were either generally similar or declining with time. In Magadi area, the buffalo numbers were either same or higher in the wet season, but still the buffalo numbers were increasing only in the wet season but declining in the dry seasons over time. In West Kilimanjaro, buffalo was only seen in the wet season of 2013 but not dry season of 2010, implying a decline in the dry season and a possible re-colonization of the area from another location in wet season when herbivores mostly disperse. In the Natron area, there was more buffalo in the wet season than dry season of 2010, and no buffalo seen at all in the area in all seasons in 2013, implying a general decline in buffalo numbers over time, and an indication of impending local extinction of buffalo in Natron area similar to West Kilimanjaro area.
As for common waterbuck, it was also interesting to note that waterbuck its numbers in locations were independent of season, and numbers were similar both near and further away from protected areas across the wet and dry season. This is contrary to what is expected. It is expected that generally herbivore numbers will depend on season, and that numbers will increase in the wet than dry season [
But again animal numbers will always not thrive in wet season when there is more forage and water. Animal ecology, particularly foraging and habitat requirements may influence how animal numbers respond to wet and dry seasons over time. For Amboseli area showed that even though wet season waterbuck numbers were higher than dry season numbers, generally waterbuck was declining with time. In Magadi/Namanga however, even though wet and dry season waterbuck numbers were similar, the general trend was an increasing waterbuck number with time. In West Kilimanjaro area, there were only 2 waterbucks in 2010 and none seen in 2013 implying local extinction was likely in West Kilimanjaro. In Lake Natron area 2010, waterbuck was only seen in wet season and not dry season. Further, only one waterbuck was seen in 2013 (wet season) implying that the number of waterbuck was declining rapidly in Lake Natron area and may be the one seen in 2013 was an immigrant, implying that local extinction of waterbuck in Lake Natron, just as lakeMagadi was also eminent. It therefore seems that waterbuck was also declining with time across locations because of lack of clear increasing population trend in all the locations.
The current status of African Cape buffalo is dependent on the animal’s value to both trophy hunters and tourists, paving the way for conservation efforts through anti-poaching patrols, village crop damage payouts, and hunting payback programs to local areas in some countries [
Buffalo ranks highly in human-wildlife conflicts because of its high incidences of attack on humans and livestock when they meet or compete for water and pasture [
The IUCN lists the waterbuck as being of Least Concern [
The waterbuck may not be a member of the famed tourism big five, but it is interesting and contributes to tourists nevertheless. The common waterbuck is a rare specialized grazer of intense tourism interest. Tourists will tend to value an animal that is easy to view and is also rare. In Amboseli National Park, a study in 2008 [
Re-colonization of buffalo and waterbuck to re-build its seriously reduced numbers that are still continuing to decline during wet season dispersal time will only be possible if less impacts from human encroachment, poaching by bush meat and habitat destruction. Management attention should be focused on all the borderland landscape, but in particular the Lake Natron and West Kilimanjaro because they had lowest numbers and are currently witnessing local extinction of buffalo and waterbuck in the borderland. With increasing of numbers in every wet season, and for every passing year in areas closer and away from protected areas, there is great potential and opportunity to get the numbers of these two species to build up again and become viable populations of the borderland meta-population.
Lastly, the safety of these two species as well as other large mammals in the borderland is critical for allowing for re-colonization of the space where wildlife large mammals in the borderland can again thrive. Increased conflicts with wild herbivores over damages (may be due to crop raiding and in some cases competition for water, pasture and space), and threats (such as bush meat poaching) and habitat destruction will lead to a steady herbivore decline in the borderland [
The status and distribution of the African buffalo and common waterbuck were very poor both in number and distribution in the mid borderland of Kenya-Tanzania. Most of the buffaloes and waterbucks, however, are found in Amboseli and Lake Natron area, but there is also a good population in Magadi/Namanga area and West Kilimanjaro in Tanzania. The population growth was negative (except in Amboseli wet season and Magadi/ Namanga Area). This raises a red flag because it means that the African buffalo and common waterbuck have not recovered from the effects of the 2007 and 2009 droughts and their population is still declining in all the areas of the borderland. These species are very water specific and localized in marshes and swamps where they are able to access water. Small populations and declining numbers mean that they can easily be wiped off by stochastic demographic and environmental parameters and undergo local extinctions. In fact, local extinctions of this species may already have happed in West Kilimanjaro and the Lake Natron Areas. Buffalos kill many people and so they also can be highly persecuted by communities and not tolerated because of their contribution to human-wildlife conflicts. Yet both buffalo and waterbuck are very attractive species to tourists and therefore contribute a lot to the tourism revenue and industry. It therefore needs concerted effort in both Kenya and Tanzania and the borderland communities to avoid poaching, retaliatory killing and insularization of the remaining populations of buffalo and common waterbuck. Further, joint monitoring between Kenya (KWS) and Tanzania (TAWIRI) will enhance science-based management through population monitoring and trend. The buffalo and waterbuck population status and distribution are poor enough in the Kenya-Tanzania borderland to make it a species of conservation concern in the borderland despite what IUCN reports indicate [
We humbly appreciate the contributions made by the Kenya and Tanzania census teams, and the incredible financial and moral support offered by various organizations and institutions. In particular, funding, personnel and logistical support were provided by AWF, KWS, TAWIRI, WD, TANAPA and ATE. We are equally grateful to the Director KWS, Director ATE, Director of Wildlife in Tanzania, Director General of TANAPA and Mr. Peter Zannetti for provision of aircraft and experienced pilots and observers. The ground crew and support personnel showed a lot of commitment which ultimately went a long way in making this research successful. Finally, we honor all those people who participated in one way or another in this exercise and whose names have not been mentioned. Their input equally contributed to the good work that was accomplished in all the census sessions.