A total of 480 sightings were reported during the study period, which resulted in 4.740 wild animals being recorded a long 3 transect lines outside Lake Mburo National Park. Based on the number of observed animals during the study against the number of sightings, the results showed mean of 9.8 (8.48-11.12) for overall group size at 95% confidence interval. We also found out that one was likely to have between two and three encounters with wild animals within 1 km2 along the distance gradient from park boundary (Table 1)
Table 1
Animal encounter rates a long distance gradient from park boundary
Survey
|
|
Transects
|
|
TS1
|
TS2
|
TS3
|
Total Observed animals
|
1845
|
1780
|
1115
|
Number of sightings
|
182
|
156
|
142
|
Mean group size
|
10.14
|
11.41
|
7.85
|
Standard error of mean
|
1.24
|
1.67
|
1.05
|
Minimum group size
|
1
|
1
|
1
|
Maximum group size
|
75
|
89
|
51
|
Encounter rate (mean groups/km2)
|
2.53
|
2.85
|
1.96
|
The results of wild ungulate survey showed that the populations of different wild animal species varied significantly (p < 0.05) between the observed and the expected equal population distribution in the study area. For example, Zebras (Equus burchelli) and Impalas (Aepyceros melampus) accounted for about 45% and 35% respectively. This means that, of all the wild ungulates counted outside the LMNP during the study period, zebra and impala alone accounted for 80% (Table 2), a clear indication of disproportionate distribution of wild animals in private farms outside protected area.
Table 2
Population abundance of wild ungulates outside LMNP
|
|
Population Abundance
|
|
|
|
Wild species of ungulates
|
Sightings
|
Total
|
% Proportion
|
X²
|
df
|
p*
|
Zebra -Equus burchelli
|
142
|
2,154
|
45.44
|
848.43
|
36
|
<0.001
|
Impala -Aepyceros melampus
|
149
|
1,654
|
34.89
|
533.43
|
27
|
<0.001
|
Bush buck -Tragelaphus scriptus
|
64
|
376
|
7.96
|
1265.53
|
13
|
<0.001
|
Waterbuck-Kobus ellipsiprymnus
|
36
|
204
|
4.34
|
1550.87
|
11
|
<0.001
|
Duiker - Sylvicapra grimmia
|
45
|
143
|
3.09
|
460.45
|
4
|
<0.001
|
Warthogs-Phacochoerus ethiopicus
|
14
|
94
|
1.78
|
1084.32
|
6
|
<0.001
|
Buffaloes -syncercus caffer
|
12
|
76
|
1.66
|
1298.71
|
7
|
<0.001
|
Eland -Taurotragus oryx
|
18
|
39
|
0.84
|
678.14
|
4
|
<0.001
|
Total
|
480
|
4,740
|
100
|
131.075
|
56
|
<0.001
|
During the study we assumed that different species of animals were equally distributed outside the gazetted area. However, the results of Table 1 show that the frequency distribution of each animal species observed on private farms during the study varied significantly. A Chi Square Test for normal distribution of proportions of wild ungulate species in the Lake Mburo Region was statistically significant (p < 0.001).
For distance gradient, the results on animal surveys showed that there was significant decrease in the population density of wild ungulates as distance increased away from the park boundary northwards (R² = 0.884, P < 0.001). Association between total abundance of wild ungulates with distance ranges from the park boundary was a negative one. The mean densities of wild ungulates significantly decreased (p < 0.001) from 59.25 at the park boundary to less than 10.25 further north of LMNP.
Overall cattle population did not have significant progressive variations between distance zones. However, the mean population density of exotic (Friesian) cattle increased significantly from 184.25 at the park boundary to 550.5 further north. On the contrary, mean population of indigenous cattle (Bos tauruss) decreased from 1107 at park boundary to 164 along the same distance gradient. Shifts in spatial pattern of population densities of cattle breeds along the same distance gradient was due to pastoralists’ economic choices, partly influenced by own perception and experience of pathogen infestations in cattle. Pastoralists associated incidences of cattle diseases with the presence of wild animals as potential risk factor for disease spill overs.
For example, majority of respondents at the park boundary reported frequent repeat use of acarides due to high degree of infestation of the cattle with ticks. It was for this reason that most households adjacent to the park preferred the indigenous cattle breed to exotic, since they believed that indigenous breed of cattle offers good resistance to tropical diseases compared to Friesian cattle. The probability of a household having exotic breed of cattle at the park boundary was 3 times lower (0.21, 95%CI) compared to 0.74, 95%CI for households situated further north of Lake Mburo National Park. In terms of acaricide use, cattle mortalities and expenditure on the services of veterinary personnel, pastoralist households incurred lesser costs of cattle diseases control in areas with significant decline of zebra and impala populations (Figure 2).
Majority of the respondents, over 83%, linked the presence of wildlife with diseases infecting their cattle. Most respondents held a strong view that wild ungulates, especially zebras, impalas and buffaloes, are not only abundant on private farms/ranches, but are also perceived as the transmission vehicle of various diseases affecting cattle production in LMCA (Table 3). Given high proportions of zebras and impalas in cattle grazing areas, it was likely that most wild ungulate related cattle disease risks, including brucellosis and tick-borne disease were due to these animals’ grazing activities outside the protected area. It also emerged that large populations of zebra and impala have probably become permanent residents on private farms and ranches around Lake Mburo National Park.
Table 3
Sources of cattle disease risks as perceived by pastoralist communities
Sources of cattle diseases, N = 366
|
Respondents
|
|
Frequency
|
%
|
1. Wild ungulates on private farms
|
234
|
63.9
|
2. Cattle grazing within the LMNP
|
72
|
19.7
|
3. Moving cattle from one herd to another
|
35
|
9.6
|
4. Others
|
25
|
6.8
|
Total
|
366
|
100.0
|
Currently many animals trapped in private ranches/farms are unable to return to the protected areas, since people have severely encroached park buffer areas which once supported ecosystems connectivity. This situation facilitates frequent interactions between these wild ungulates and cattle in rangelands, thereby resulting in the spread of diseases.
We estimated annual cost of controlling ticks and treating sick cattle at herd level to be US $ 178 – 287 (at exchange rate of USD 1: UGX 2500). The expenditure pastoralist households incur on cattle diseases control also varied between distance zones, with communities living adjacent to the national park incurring higher costs compared to their counterparts situated further away from the park boundary. Our findings revealed that the costs of diseases control outweighed the benefits accrued from sales of milk among pastoralist households located within 8 km from the park boundary. On the contrary, the losses households located beyond 10 km away from the park incurred due to cattle diseases control were significantly lower (p < 0.05) than the benefits from sales of milk.
Table 4: Household incomes versus costs of disease control (in UGX 1000) by distance zone
Distance
|
No.
|
Mean cattle
|
Income from
|
Cost of
|
Mean Difference
|
P-value
|
Zones (km)
|
H/holds
|
Heads
|
Milk
|
Diseases
|
95% CI
|
|
0 - 4
|
60
|
91.7 ± 10.50
|
4931.67
|
5615.01
|
683.33 ± 611.10
|
0.041
|
4 - 8.
|
58
|
152.2 ± 18.6
|
6215.52
|
7181.04
|
965.52 ± 672.99
|
0.053
|
8 - 12.
|
64
|
85.9 ± 05.80
|
7454.1
|
5149.22
|
2304.69 ± 294.11
|
0.012
|
12 - 16.
|
60
|
65.0 ± 04.80
|
8430.01
|
4837.51
|
3592.50 ± 520.95
|
0.005
|
16 - 20
|
62
|
65.0 ± 06.30
|
9616.13
|
4735.48
|
4880.65 ± 341.67
|
0.003
|
20 - 24
|
62
|
56.8 ± 04.20
|
8056.45
|
4460.48
|
3595.97 ± 987.95
|
0.006
|
Mean differences between income from sale of milk and expenditure on diseases control was statistically significant at p ≤ 0.05.
Three breeds of cattle are reared by pastoralists in different proportions, across six distance zones. Spatial pattern of cattle breed populations illustrated in Figure 3 suggest that pastoralists’ perception of disease risks as a function of distance from the Lake Mburo National Park had some influence.