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Annual Research and Monitoring Report, 2007
Conservancy
Lewa Wildlife
Lewa Wildlife Conservancy
Research and Monitoring
Annual Report 2007
Geoffrey Chege and Edwin Kisio
February 2008
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
ACKNOWLEDGEMENTS
The staff of the Lewa Research and Monitoring Department would like to thank the following
individuals and institutions for their unwavering moral, logistical and financial support of activities
completed in 2007: The Board of Lewa in Kenya, USA, UK and Canada, Dr Tim Woodfine,
Tanya Langenhorst and Guy Parker, Grevy’s Zebra Trust, Kenya Wildlife Service, Management
of Lewa, Marwell Conservation, Mulhouse Zoo through Pierre Moisson, Mpala Research Centre,
Northern Rangelands Trust, Princeton University, Prof Dan Rubenstein, Richard and Rhoda
Goldman Fund, Sacramento Zoo, Save The Elephants, Saint Louis Zoo, Safaricom Ltd, Tusk
Trust, Toronto Zoo, US Fish and Wildlife Society, Wilhelma zoologisch-botanischer Garten
Stuttgart, Zucher Tuitchetz and Zurich Zoo.
Finally, special thanks to the security personnel who gather basic wildlife monitoring data in the
field together with other staff who offer logistical support to the department.
Without all your contributions, the specific details described in this report would not have been
completed.
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
EXECUTIVE SUMMARY
In 2007, the Research Department of Lewa undertook several pertinent research and monitoring
activities aimed at providing insight into specific management issues to better inform decisions
on proactive management of species and habitats in the Conservancy.
Black rhino
The population of black rhinos rose to 55 following three births representing 5.7% growth rate
compared to the national meta-population target of 5%. The average growth rate since 2000 has
been 10%. Mean inter-calving interval was 2.5 years with several calving intervals being <2.0
years. In particular, Mawingo’s last two inter calving intervals were ≤1.6 years. This was
exceptional considering that the gestation period of black rhinos is 18 months. Overall, Lewa’s
population performance in the year was above average compared against standard benchmarks
for evaluating performance of black rhinos. All rhinos either maintained or improved their body
condition due to the 2007 rains. Six “clean” rhinos were notched for identification. Introduction
of camels into the extreme western side of the former Manyagalo Ranch and increased human
activities in the central parts appeared to negatively affect the spatial and temporal utilisation
patterns of rhinos in the two areas. The carrying capacity of black rhinos was estimated to be
70. Surplus production will need to be moved out in the next two years.
It was recommended that the population of black rhinos on Lewa should be maintained at
maximum sustained yield of 52 non-sex biased stock for maximum productivity. Efforts should
be enhanced to either extend the existing IL Ngwesi sanctuary and translocate excess animals
out of LWC or to amalgamate Lewa and Borana and ultimately with Il Ngwesi in the next five
years in order to raise the ecological carrying capacity of the expanded area to about 160
animals and become a Key 1 rated population. Before this happens, there will be need to closely
monitor activities of the upcoming adult bulls for remedial actions to be undertaken as necessary.
White rhino
The population of white rhinos stood at 37 animals. There were two births in the year. Age at
first calving was 7.9 years and inter-calving interval was 2.5 years. Seven rhinos have been
translocated to Ol Pejeta in the last two years in order to achieve a balanced sex ratio, and
establish a founder and breeding stock of the same at OPC.
Even though Guidelines on Management of White Rhinos in the country do not advocate rapid
growth of this species, it was recommended that the current growth rates in LWC should be
maintained in order to attain stocks that can be moved to other private and community areas on
custodianship agreement basis. For such rates to be achieved, an active balancing programme
should be continuously pursued in order to stock a non-sex biased population.
Grevy’s zebra
The Grevy’s zebra population stood at 430 compared to 399 in 2006 representing a potential 7%
population increase. At least 69 foals were born in the year. Survival rate of these foals at the
close of the year was 70%. However, this rate was expected to further reduce as monthly foal
patrols continued in 2008. The overall recruitment rate into juveniles’ stage of foals born in 2006
was 49% which compared well with 2005 when 47% of foals were recruited. However, the
survival rate of foals born on Lewa since 2004 has been below 50% which is the minimum infant
survival per annum required for Lewa’s Grevy’s zebra to increase in numbers.
Scat analysis of lions showed that zebras continued to form the main diet of lions with twice as
much Plains zebra being predated compared to Grevy’s zebra. This contrasted with 2003-2005
when the two zebras were predated almost equally. This lowered rate of predation may have
been due to a reduction in lion numbers arising from emigration. This demonstrates the potential
benefits that Grevy’s zebra population can achieve when low numbers of lions are maintained in
the Conservancy.
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Consequently, it was recommended that in collaboration with Kenya Wildlife Service, lions in
Lewa should be maintained at agreeable low thresholds to avoid negative predator-Grevy’s
zebra interactions. Such site specific plans have already been incorporated in the National
Grevy’s Zebra Strategy Plan, 2007 and have been proposed for inclusion in the National Lion
and Hyena Strategy Plan (in preparation).
General Wildlife Monitoring
The annual game count showed that most of the key wildlife species registered an increment in
numbers when compared to the 2006 count. In particular, eland, oryx, Grevy’s zebra, Plains
zebra, giraffe and ostrich registered positive trends while waterbuck had a negative trend.
Rainfall
Lewa received 620 mm of rainfall in 2007 compared to 758 mm in 2006. This contrasted with
286 mm that was received in 2005. This amount of rainfall was also way above the long term
mean rainfall of 517 mm averaged since 1972.
Management issues
A number of issues that have a direct impact on the current status of LWC’s biodiversity were
evaluated. Intensive community cattle grazing was found to have a positive impact in improving
the range for Grevy’s zebra. In order to achieve extensive optimal results and suit LWC’s
ecological and environment conditions, it was recommended that at least 4 bunches of
community cattle with a minimum of 500 herds per bunch, should be grazed and paddocked in
the Conservancy. In future, both cattle grazing and prescribed burning should compliment each
other for extensive results to be achieved.
The ecological impacts arising from the annual marathon were similarly evaluated. The
significant impacts were categorised into four: depletion of resources; pollution; vegetation
degradation; disruption of animal behaviour; and physical impacts.
Large stands of Datura stramonium were found to prevent growth of grass and herbaceous
material in the heavily infested areas. The plant was insignificantly utilised by browsers. It was
recommended that the existing early detection and monitoring programmes of invasive species
be maintained. Similarly, regular surveys of known infestation areas should be initiated by laying
of transects to monitor the rate of spread or reduction. Again, elimination of D. stramonium
should be effected before the fruiting stage.
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
TABLE OF CONTENTS
ACKNOWLEDGEMENTS .............................................................................................................. i
EXECUTIVE SUMMARY .............................................................................................................. ii
TABLE OF CONTENTS ............................................................................................................... iv
LIST OF FIGURES....................................................................................................................... vi
LIST OF TABLES.........................................................................................................................vii
1.
RHINO MONITORING .......................................................................................................... 1
1.1.
Status and performance of black rhinos in Lewa as at December 2007 ....................... 1
1.2.
Population growth rate in 2007 ..................................................................................... 2
1.3.
Ecological carrying capacity of rhinos on LWC ............................................................. 3
1.4.
Predicted future rhino growth rates and numbers in LWC ............................................ 5
1.5.
Projected future expansion programmes for the benefit of rhinos................................. 6
1.6.
Population performance indicators ............................................................................... 7
1.7.
Milestones in LWC’s rhino conservation efforts ............................................................ 7
1.8.
Home ranges of black rhinos ........................................................................................ 8
1.8.1.
Breeding female black rhinos ............................................................................... 8
1.8.2.
Breeding males black rhinos................................................................................. 9
1.9.
2.
Translocation .............................................................................................................. 12
1.10.
Ear notching of black rhinos ................................................................................... 12
1.11.
Recommendations.................................................................................................. 12
1.12.
Rhino body condition scores................................................................................... 12
1.13.
Performance of white rhino in Lewa........................................................................ 13
1.13.1.
Status of white rhinos in LWC, 2007............................................................... 13
1.13.2.
Growth rate in 2007 ........................................................................................ 14
1.13.3.
Sex ratio and translocation ............................................................................. 15
1.13.4.
Overall performance of white rhino on LWC ................................................... 15
GREVY’S ZEBRA RESEARCH AND MONITORING.......................................................... 16
2.1.
Introduction ................................................................................................................. 16
2.2.
Methods ...................................................................................................................... 17
2.3.
Results and discussion ............................................................................................... 17
2.3.1.
Dynamics of Grevy’s zebra numbers in 2007 ..................................................... 17
2.3.2.
Survival and recruitment rates of foals born in 2006........................................... 18
2.3.3.
Survival and recruitment rates of foals born in 2007........................................... 18
2.4.
Seasonality of foaling.................................................................................................. 19
2.5.
Inter-foaling interval .................................................................................................... 20
2.6.
Distribution of lactating females and foals in 2007...................................................... 21
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Annual Research and Monitoring Report, 2007
3.
Lewa Wildlife Conservancy
PREDATOR MONITORING IN LEWA ................................................................................ 23
3.1.
Lion profile on LWC as at 2007................................................................................... 23
3.2.
Collaring, tracking and identification of lions ............................................................... 23
3.3.
Collection of scat ........................................................................................................ 23
3.4.
Scat and hair analysis................................................................................................. 24
3.5.
Results and discussion ............................................................................................... 24
3.5.1.
Dynamics of lion population in Lewa .................................................................. 24
3.5.2.
Scat and hair analysis in 2007............................................................................ 25
3.6.
Comparative assessment of predation rates, 2004-2007 ........................................... 26
3.7.
Conclusion .................................................................................................................. 26
4.
TRACKING OF COLLARED GREVY’S ZEBRA IN NORTHERN KENYA........................... 27
5.
GENERAL WILDLIFE MONITORING ................................................................................. 30
5.1.
6.
7.
Annual game census .................................................................................................. 30
ECOLOGICAL MONITORING ............................................................................................ 33
6.1.
Rainfall in 2007 ........................................................................................................... 33
6.2.
Vegetation monitoring ................................................................................................. 34
6.2.1.
Grass assessment .............................................................................................. 34
6.2.2.
Prescribed burning ............................................................................................. 34
6.2.3.
Fixed point photography ..................................................................................... 34
MANAGEMENT ISSUES .................................................................................................... 35
7.1.
Improvement of rangeland for Grevy’s zebra.............................................................. 35
7.1.1.
Background ........................................................................................................ 35
7.1.2.
Methods.............................................................................................................. 36
7.1.3.
Results and discussion ....................................................................................... 37
7.1.4.
Impact of the programme and future .................................................................. 38
7.1.5.
Recommendations.............................................................................................. 38
7.2.
Management of invasive species................................................................................ 39
7.2.1.
Invasive and alien species in LWC ..................................................................... 39
7.2.2.
Control of invasive species in LWC .................................................................... 40
7.3.
Impact of the Marathon ............................................................................................... 42
7.3.1.
Depletion of natural resources............................................................................ 42
7.3.2.
Disturbance to biodiversity.................................................................................. 42
7.3.3.
Pollution.............................................................................................................. 43
7.3.4.
Physical impacts................................................................................................. 43
7.3.5.
Compromise in wildlife monitoring activities: ...................................................... 43
8.
REFERENCES ................................................................................................................... 45
9.
APPENDIX 1: BREEDING PERFORMANCE OF RHINOS ON LEWA, 1985 - 2007 .......... 46
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Lewa Wildlife Conservancy
LIST OF FIGURES
Figure 1.1: Sex and age structure of black rhinos in Lewa, December 2007 ................................ 1
Figure 1.2: Number of calves born per breeding female black rhino in Lewa: 1984-2007............. 2
Figure 1.3: Trend in black rhino population including births, deaths, translocations and temporal
growth rates on LWC, 2000-2007 ................................................................................................. 3
Figure 1.4: A hypothetical production curve of rhinos showing density dependent declines in
performance beyond 75% of ECC with zero growth rates at ECC level........................................ 4
Figure 1.5: The relationship between the current population, predicted ecological carrying
capacity and maximum sustained yield, and surplus production that need to be regularly
removed to maintain maximum growth rates of rhinos on LWC, 2007 .......................................... 5
Figure 1.6: Predicted performance of black rhinos on LWC at 6% and 9.4% p.a. growth rate...... 5
Figure 1.7: The relationship between MSY, current population and future population numbers on
LWC based on 6% and 9.4% growth rates ................................................................................... 6
Figure 1.8: Location of LWC showing the possible expansion routes to Borana and IL Ngwesi
Group Ranches for subsequent colonisation by black rhino ......................................................... 7
Figure 1.9: The ranging areas of four breeding female black rhinos on LWC, 2007 ..................... 9
Figure 1.10: The ranging areas of five breeding female black rhinos on LWC, Jan-Sept 2007... 10
Figure 1.11: Ranging areas of Mama C and Seiya between Jan. – Sept. & Oct. – Dec. 2007.... 10
Figure 1.12: Ranging areas of Ndito and Nashami between Jan. – Sept. & Oct. – Dec. 2007.... 11
Figure 1.13: Ranging areas of Oboso and Zaria between Jan. – Sept. & Oct. – Dec. 2007 ....... 11
Figure 1.14: The ranging areas of Sonia between Jan. – Sept. & Oct. – Dec. 2007 ................... 12
Figure 1.15: Sex and age structure of white rhinos on LWC, December 2007............................ 14
Figure 1.16: Number of calves born per breeding female white rhino in LWC: 1984-2007 ......... 14
Figure 1.17: Trend in white rhino population including births, deaths, translocations in LWC..... 15
Figure 2.1: Grevy’s zebra population trends in Lewa and Kenya’s Rangelands, 1978-2007...... 16
18
Figure 2.2: Comparison of survival rate of Grevy’s zebra foals born on LWC, 2003-2007 ......... 18
19
Figure 2.3: Comparison of Grevy’s zebra foals born annually on Lewa since 2003 ................... 19
20
Figure 2.4: Age of Grevy’s zebra foals born in 2007 and still surviving at end of the year.......... 19
21
Figure 2.5: A comparison of numbers of Grevy’s zebra foals born per month on LWC against the
22
2007 rainfall – note the non-synchrony of foaling with the rains.................................................. 20
Figure 2.6: A comparison of numbers of Grevy’s zebra foals born per month on LWC against the
23
2006 rainfall – note the non-synchrony of foaling with the rains.................................................. 20
Figure 2.7: Proportional inter-birth intervals for Grevy’s zebra on LWC, 2007............................ 21
24
Figure 2.8: Distribution of Grevy’s zebra foals and juveniles on LWC, 2007 .............................. 22
25
Figure 3.1: Performance of Grevy’s zebra and lions in LWC, 1996-2007 ................................... 24
26
Figure 3.2: Trend in the number of lions on LWC, 2000-2007 .................................................... 25
27
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Figure 3.3: A comparison of the proportion of equids versus bovid hair found in lion scat on
28
LWC, 2004-2007 ......................................................................................................................... 25
Figure 3.4: Comparative assessment of predation rates of Grevy’s and Plains zebra from hairs
29
found in lion scat ......................................................................................................................... 26
Figure 4.1: Movement patterns of 3 collared Grevy’s zebra in Laisamis area, Feb. – Jul. 2007. 28
30
Figure 4.2: Movement patterns of one collared female Grevy’s zebra between food and water in
31
Laisamis area covering 280 km from 1-14 Mar. 2007 ................................................................. 28
Figure 4.3: Movement patterns of Liz (June 2006 – March 2007) showing the extensive
32
distances travelled by the Grevy’s zebra from the National Reserves to the community areas of
Kalama and West Gate (mapping by Henrik B. Rasmussen)...................................................... 29
Figure 5.1: Comparison of the dynamics of some key wildlife species on LWC, 2006-2007 ...... 30
33
Figure 5.2: Trend in Grevy’s and Plains zebra numbers, 1999-2007.......................................... 32
34
Figure 5.3: Trend in Buffalo, Eland and Waterbuck numbers, 1999-2007 .................................. 32
35
Figure 6.1: Monthly rainfall received in LWC (2005-2007) against the long-term mean ............. 33
37
Figure 6.2: Amount of rainfall received per station in LWC, 2007............................................... 33
38
Figure 7.1: Diagrammatic representation of the systematic rotation of cattle pens..................... 37
39
Figure 7.2: A section of the cattle pen showing impact of intense cattle trampling for 5 days .... 37
40
Figure 7.3: A comparison of location of cattle pen sites versus non-pen sites/non-grazed areas
41
showing the impact of trampling and subsequent phased grass regeneration............................ 38
Figure 7.4: Distribution of Datura stramonium on LWC, 2006 – 2007 ........................................ 41
42
Figure 7.5: Areas that witnessed significant wildlife disturbance due to the Marathon ............... 44
43
LIST OF TABLES
Table 1.1: Sex and age structures of black rhinos in Lewa, December 2007................................ 1
Table 1.2: Inter-calving intervals of female black rhinos in Lewa, December 2007 ....................... 2
Table 1.3: Performance of LWC’s rhino population against set benchmarks ................................ 8
Table 1.4: Black rhino body condition scores .............................................................................. 13
Table 1.5: Sex and age structures of white rhinos on LWC, December 2007 ............................. 14
Table65.1: Game count figures in Lewa, 2001-2007................................................................... 31
Table 7.1: Exotic plant species found in LWC as at Dec. 2007 (from Giesen et al., 2007) ........ 39
Table87.2: Some pertinent data on the impact of Safaricom Marathon ...................................... 44
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Lewa Wildlife Conservancy
1. RHINO MONITORING
1.1.
Status and performance of black rhinos in Lewa as at December 2007
The population of black rhinos in Lewa Wildlife Conservancy (LWC) stood at 55 animals
comprising of 16 calves (0≤3 years); 13 sub adults (3≤6 years); and 26 adults (>6 years) (Table
1.1; Figure 1.1). The sex ratio of males to females was 1:1.1.
Three births were recorded in 2007 compared to eight in 2006. Seiya (8.7 years) gave birth to
her 2nd offspring while Waiwai (12.5 years) and Mawingo (18.6 years) gave birth to their 3rd and
6th calves respectively (Figure 1.2). Mawingo’s last two inter-calving intervals were 18 and 19
months respectively (Table 1.2; Appendix 1). This is significant considering that the gestation
period of black rhinos is 16 months. The two inter-calving intervals are the shortest in LWC and
may be among the least in the country. Most of the breeding females born in LWC have intercalving intervals <2.5 years suggesting a settling effect of the rhinos (Table 1.2; Appendix 1).
It is predicted that 10 females will calve in 2008 (Figure 1.3). This prediction is based on the
mean inter-calving interval of each female and age at first calving of 7.0 years for first time dams.
Stumpy (nearing natural attrition age of c.40 years) and Solio are the oldest breeding females in
LWC and are expected to calve to their 8th and 9th calves respectively. To date, both Stumpy
and Solio have given birth to 7 and 8 calves respectively since they were introduced in LWC in
the 1980’s (Figure 1.2). The only other known female to have produced such high number of
calves was from Ol Jogi which was credited with 8 calves before she succumbed at c.40 years.
Table 1.1: Sex and age structures of black rhinos in Lewa, December 2007
Age class
Males
Females
Not sexed
Sub total
Proportion in
population
Calves (0≤1 year)
-
2
1
3
5%
Calves (1<3 years)
8
3
2
13
23.5%
7
6
-
13
23.5%
Adults (6<30 years)
9
15
-
24
44%
Adults (>30 years)
-
2
-
2
4%
Grand total
24
28
3
55
100%
Sub-total
Sub-adults (3<6
unless calved)
years
16
14
12
10
8
6
4
2
0
Calves
Calves
Sub adults
Adults
Adults
(0≤1 years ) (1<3 years ) (3<6 years) (6-30 years) (>30 years )
Males
Fem ales
Uns exed
Figure 1.1: Sex and age structure of black rhinos in Lewa, December 2007
1
Proportion of
population that is
actively breeding
Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
6
4
2
0
So
St lio
um
M
p
aw y
in
go
Za
J u ri a
ni
pi
er
N
di
to
N
yo
ta
So
n
W ia
ai
w
M ai
el
ua
ya
Se
iy
Sa a
m
i
O a
bo
N
as so
ha
m
N i
at
um
i
No. of calves/female
8
Figure 1.2: Number of calves born per breeding female black rhino in Lewa: 1984-2007
Table 1.2: Inter-calving intervals of female black rhinos in Lewa, December 2007
Inter-calving intervals
st
Age at 1
No. Female name Current age calving (yrs)
Juniper
19.5
1
7.6
18.6
2
Mawingo
**
Meluaya
11.9
3
8.4
Ndito
18.0
4
9.3
Nyota
11.9
5
7.8
Solio
32.0
6
**
Sonia
16.4
7
7.1
Stumpy
39.0
8
**
Waiwai
12.5
9
6.8
19.8
10 Zaria
7.8
11 Seiya
8.7
5.5
9.5
12 Nashami
7.6
9.3
13 Natumi
6.7
9.3
14 Samia
8.2
7.2
15 Oboso
5.4
st
Mean age at 1 calving =
7.3
1
2
3
4
3.2
2.2
1.9
3.2
2.7
3.1
4.7
**
2.1
2.3
2.7
2.3
2.8
2.2
2.4
3.5
2.4
3.9
2.3
2.1
-
2.2
1.7
2.1
1.5
3.9
2.8
3.0
-
2.3
1.5
3.2
2.2
2.2
-
5
6
7
1.6
2.1
2.9
2.3
3.0
2.0
Mean inter-calving interval =
Mean calving
interval/
female
2.5
2.0
1.9
2.5
2.2
3.0
3.6
2.8
2.2
2.4
2.7
2.5
1.2.
Population growth rate in 2007
In 2007, the population of black rhinos in LWC had an overall growth rate of 5.7%. This rate was
slightly lower than that recorded between 2000-2003 and 2003-2005 (Figure 1.3). However, this
lowered rate was expected considering that growth rates in 2005-2006 hit a record high of 15%
p.a. with 13 out of the 15 breeding females with calves <2.0 years in 2007. Nevertheless, this
rate was above the national metapopulation target of 5%1 as was recommended in the national
Black Rhino Strategy Plan, 2000-2005 (KWS, 2000).
In 2006, potential factors that may have led to the very high growth rates of black rhinos
observed in LWC since 2000, and that exceeds the intrinsic rate of increase (rmax = 9.4%) for
non-sex biased rhino populations were discussed2. It was also mentioned that it is critical for
LWC and all other rhino areas in Kenya to maintain such high growth rates since large, rapidly
1
Since then, a revised Conservation and Management Strategy Plan for the Black Rhino and Management Guidelines for the
White Rhino in Kenya that targets an annual growth rate of 6% in established sanctuaries including LWC, has been produced.
2
Factors needed to achieve high growth rates are contributed by: (i) a non-sex biased population that is expanding as a result
of active breeding and has a young age structure; and (ii) when a population as described in (i) is in good habitat.
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
breeding and healthy populations not only provide the best insurance against any future
poaching events, but also prevents loss of heterozygosity by ensuring maximum rate of gene
transfer to future generations (Okita-Ouma, Amin, Adcock, Emslie, Pearce-Kelly and Kock,
2007). It is from this realisation that LWC will need to either translocate its excess stock of
rhinos in the next two years or expand into the neighbouring Borana and Il Ngwesi Ranches so
as to maintain current productive levels, and for the overall population to attain a Key 1 rating3 as
per the AfRSG guidelines (Emslie and Brooks, 1999).
5.7%
15%
13%
10
Growth rates for
the period
60
55
12%
50
8
6
40
4
29
30
Population size
No. of births/deaths/
translocations per year
12
2
0
20
2000 2001 2002 2003 2004 2005 2006 2007 2008
Years
No. calves
Translocations OUT
Deaths
Population size
Predicted biths in 2008
Figure 1.3: Trend in black rhino population including births, deaths, translocations and temporal
growth rates on LWC, 2000-2007
1.3.
Ecological carrying capacity of rhinos on LWC
The ecological carrying capacity (ECC) of black rhinos in LWC was reviewed in 2004-2005 using
a multi-faceted model for estimating the holding capacity of rhinos in the nine well-established
rhino sanctuaries in Kenya (Okita-Ouma et al., 2007). The model took into account productivity
and quality of the standing crop of browse (based on 150 detailed vegetation transects on LWC),
and also put into consideration other auxiliary data4 on variables that affect ECC of rhinos. This
information was combined with Landsat-7 satellite imagery data to give overall browseavailability and browse suitability index maps for LWC.
Using the above parameters, the mean ECC of black rhinos in the Conservancy was adjusted
from the initial 83 animals estimated in 2006 to 70 (range 61 to 80) (Okita-Ouma et al., 2007). It
is imperative to note that the maximum sustained yield (MSY) for large bodied animals e.g. black
rhinos is attained at 75% of ECC, and that exceeding stocks beyond this level is characterised
by a tumble in annual growth rates over time as the population under review manifests density
dependent declines (Figure 1.4) (Amin et al., 2006). With this in mind, a population that is at
MSY has the capacity to produce maximum surplus production that can be translocated without
compromising the stock and productivity levels as long as all other factors are held constant.
Therefore, in the case of LWC, the MSY of rhinos is 52 (using ballpark figure of 70 = ECC)
(Figure 1.5). Hence, with the current population at 55, in theory, MSY has already been
exceeded by three animals. Therefore, if the ECC and hence the MSY are correct, then LWC’s
3
4
A population that is increasing or stable and n > 100
Such data include soils, populations of competing browsers, long-term rainfall and temperature.
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
population will start showing reduced annual growth rates in the coming years unless remedial
actions are undertaken as soon as possible.
However, in reality, the estimated ECC will need to be regularly reviewed since:
(i)
The dynamics of the numbers of competing browsers is expected to change on a
temporal basis and will affect the ECC of rhinos. This is because cumulative browser
impacts alter the carrying capacity in the rhino feeding layer, since competitors like
elephants remove most of the vegetation lying within 2m (critical feeding level of rhinos)
from the ground level. Such a case was observed in Ngulia Rhino Sanctuary (OkitaOuma et al., 2007) until the elephant population had to be reduced.
(ii)
Large, long-lived animals like rhino have the ability to overshoot the ECC for several
years before feedback from the habitat conditions affects population performance
indicators (Amin et al., 2006) (growth rate, age at first calving, percentage of females
calving per year, proportion of calves in the population, sex ratio etc) e.g. as witnessed in
the Solio population5 up and until 2007 when 27 rhinos were translocated out.
It imperative to note that habitat monitoring procedures have already been developed to
help provide an additional early warning system in the carrying capacity of rhinos. In line
with this, one LWC research staff was trained in the use of such techniques.
10
r max = 9.4
Growth rate (%)
8
6
4
2
0
0
10
20
30
40
50
60
70
80
90
100
Ecological carrying capacity (%)
Density independent
phase
Density
dependent phase
Figure 1.4: A hypothetical production curve of rhinos showing density dependent declines in
performance beyond 75% of ECC with zero growth rates at ECC level (Amin et al., 2006)
5
This population had a disproportionate age structure that was heavily biased towards adults and a skewed sex ratio in favour
of males as the population had overshot the carrying capacity and past removes were not based on monitoring data.
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
10
Surplus Production that
should be removed
regularly to attain MSY
and maintain growth
rates at rmax = 9.4% p.a
Growth rate %
r max = 9.4%
5
0
Population level
75% of ECC
≡ MSY = 52
Current
population
= 55
ECC
= 70
Need regular
review due to
flactuating biotic
and abiotic factors
Figure 1.5: The relationship between the current population, predicted ecological carrying
capacity and maximum sustained yield, and surplus production that need to be regularly
removed to maintain maximum growth rates of rhinos on LWC, 2007
1.4.
Predicted future rhino growth rates and numbers in LWC
The minimum metapopulation growth rate of black rhinos in the well established sanctuaries in
Kenya, including LWC has been set at 6% (Okita-Ouma et al., 2007). This rate has been
attained in the Conservancy in the past few years where growth rates have even exceeded the
intrinsic rate of increase = 9.4% p.a. Similarly, as stated in earlier, the MSY of black rhinos in
LWC (c. 52) has already been realised. However, using past performance of this population as a
guide (mainly between 2000-2006), and the fact that rhinos can overshoot their carrying capacity
for several years before density dependent declines are noted, the time taken to reach ECC of
black rhinos in the Conservancy has been modelled using the metapopulation target of 6% p.a.
and rmax = 9.4% p.a., assuming all other factors remain constant within the life of the current
Black Rhino Strategy Plan in the country.
Using the above model, at 9.4% p.a. growth rate, the population will hit the ECC of 70 by 2010
while it will take 1½ years more to reach the same figure at 6% p.a. (Figure 1.6). Using the
same projection, the relationship between the current population and estimate of numbers at the
close of each year until 2013 is shown in Figure 1.7.
No. of black rhino in Lewa
under different growth rates p.a.
100
Time to reach
ECC at 6%p.a.
growth rate
Time t o reach
ECC at 9.4%
p.a. growt h rat e
90
80
94
77
70
60
50
55
55
40
2007
2008
2009
2010
2011
2012
2013
Years
6% per annum
9.4% per annum
Figure 1.6: Predicted performance of black rhinos on LWC at 6% and 9.4% p.a. growth rate
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
100
Population of black rhinos
in Lewa
90
80
70
ECC = 70
60
MSY = 52
50
40
2007
2008
2009
2010
2011
2012
2013
9.4% per annum
55
60
66
72
79
86
94
6% per annum
55
58
62
65
69
73
77
Figure 1.7: The relationship between MSY, current population and future population numbers on
LWC based on 6% and 9.4% growth rates
1.5.
Projected future expansion programmes for the benefit of rhinos
As discussed in section 1.3, the factors affecting the ECC of rhinos in LWC will vary over time
due to several external factors. Therefore, for LWC’s black rhino population growth rates and
maximum productivity to be sustained in future, there is need to continuously remove surplus
production that overshoots the MSY (Figure 1.5).
Translocation of surplus animals for long distances may not be economically and ecologically
sustainable as few areas in Kenya are available or suitable for the establishment/augmentation
of existing stocks. Similarly, the current Black Rhino Strategy Plan lay emphasis on the crucial
role that partnership between government, private and communities6 can play in future rhino
conservation ventures. Based on this information, the most readily available options for LWC’s
rhino expansion programmes would be:
(i)
(ii)
In the medium term, continue to liaise with Il Ngwesi Group Ranch for the expansion
of its existing rhino sanctuary and translocate a minimum founder population from
LWC into the area. Such plans should follow all relevant KWS guidelines and
approvals.
Amalgamate LWC with Borana Conservancy and Il Ngwesi Group Ranch in the longterm (Figure 1.8). Using experience gained from elsewhere (e.g. Ol Pejeta), a
decision should be made on whether to immediately drop the dividing fence lines or
to translocate in a phased manner excess animals into Borana, with subsequent
dropping of the dividing fence once the two populations have established
themselves. As in (i) above, acceptable standards of security and biological
monitoring techniques in these areas have to be put in place and verified by all
concerned stakeholders. The expanded range including Ngare Ndare Forest
Reserve will be approximately 450 km2 with an estimated ECC of about 160 rhinos.
If this is achieved, it is predicted that the LWC/Borana/Il Ngwesi stock will be among
the first populations to be rated as Key 1 Population in Kenya as described by the
AfRSG of the IUCN (Emslie and Brooks, 1999).
6
Community participation has been identified as one of the strategic objectives needed to attain a vision of 2000 black rhinos in
the wild as captured in the current Black Rhino Strategic Plan & Management Guidelines for White Rhinos in Kenya (2007).
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Phase 1
Phase 2
Figure 1.8: Location of LWC showing the possible expansion routes to Borana and IL Ngwesi
Group Ranches for subsequent colonisation by black rhino
1.6.
Population performance indicators
The performance of LWC’s black rhino population was evaluated against standard benchmarks
for assessing the level of performance of any rhino population. Overall, LWC’s rhino
performance was above average and this was consistent with similar trends observed in the
Conservancy since 2000 (Table 1.3). In particular, some rhinos (e.g. Mawingo) have been
performing exceptionally well and have registered inter-calving intervals of <1.6 years. Similarly,
inter-calving intervals and age at first calving have remarkably reduced in all the females e.g. two
females born in LWC calved at 5.5 and 5.4 years respectively (Table 1.2).
1.7. Milestones in LWC’s rhino conservation efforts
The total area available to black rhinos has been increased from 5,000 acres in 1984 to the
current 62,000 acres that incorporates different land holdings. Within the same time, 61 calves
have been born while 9 individuals have been translocated out to establish new populations
elsewhere in line with the metapopulation management of rhinos in Kenya. Annual growth rates
since 2000 have averaged 10%. Inter-calving intervals have averaged 2.5 years with several
females having calving intervals <2.5 years. Age at first calving averages 7.3 years with two
females calving at ≤5.5 years. In terms of mortality, only 3 rhinos have been lost since 2000
from causes that can be explained.
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Table 1.3: Performance of LWC’s rhino population against set benchmarks
Benchmark
Minimum
recommended
Comments for LWC
rhino
6%
Level of LWC’s
performance in
2007
5.8%
Growth rate
Inter-Calving Interval
2.5 years
2.5 years
Good
% Adult Females Calving/year
At least 40%
20%
Below average
Age at First Calving
<7.0 years
7.3 years
Moderate
Sex Ratio
Minimum
1M : 1.2F
Good
% of Calves in Population
At least 28%
29%
Good
Average Mortality Rates
Maximum 4%
0
Excellent
1.8.
1M : 1F
Just below average
Home ranges of black rhinos
1.8.1. Breeding female black rhinos
As in the previous years, the breeding female black rhinos in the Conservancy appeared to have
permanently established their homeranges in specific areas of LWC (Figure 1.9 and 1.10).
However, in 2007, Ndito, Seiya, Nashami and Mama C appeared to have shifted their core
ranging areas from the extreme western edge of the former Manyagalo Ranch when evaluated
using a step-wise 50-95% kernel homerange analysis between January – September and
October – December 2007 (Figure 1.11 – 1.12). This may have been as a result of entry of
camels into the area in September 2007 thus affecting the spatial and temporal distribution
patterns of the rhinos. It would be critical to monitor the continued presence of camels in this
area for effects on growth of the woody vegetation and utilisation, and further impact on the
distribution of rhinos.
Zaria, Oboso, Samia and Sonia concentrated their ranging areas in the relatively open Soboiga
area (Figure 1.13 – 1.14). These areas are dominated by Aspilia, Hibiscus, Abutilon and
Indigofera spp. which form key black rhino diet. Similarly, the core areas of these rhinos
appeared to avoid Manyagalo exclusion zone compared to previous years when they used to
colonize the area due to its high browse productivity. Avoidance of this exclusion zone may
have been as a result of a number of factors including increased human traffic to and from
Manyagalo community. Similarly, the area has witnessed infrastructural development in the last
one year probably leading to more effects on the spatial and temporal distribution of rhinos.
BB (4.2 years) shifted her home range to the eastern side of the Conservancy from Soboiga.
This behaviour was previously observed in other sub adult rhinos (Tana, Lacky, Nashami and
Maxxine) probably in search of ideal calving grounds and territories.
Meluaya and Waiwai remained in the northern areas of the Conservancy which forms rocky and
hilly kopjes. These areas are relatively thick and contain palatable browse mainly of Acacia,
Maytenus, Commiphora and Euphobia spp.
Since the introduction of the grazing programme at Fumbi block in April 2007, the black rhinos
residing in the area were observed to co-exist with cattle with no major shifts in the ranging areas
being observed.
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Lewa Wildlife Conservancy
1.8.2. Breeding males black rhinos
All the breeding males Melita (24.0 years), James (24.2 years), Mutane (19.0 years), Amuri (20.5
years) and Lacky (11.6 years) maintained their ranging areas. James and Mutane had the
smallest home range. James who previously reside on the extreme western edge of former
Manyagalo Ranch shifted to Njora and Kona ya Manyagalo probably as a result of the
introduction of camels into the extreme corner of the former Manyagalo ranch. Melita who used
to roam widely in the previous years was noted to have been pushed to the northern confines by
Lacky who established his home range on Mlima mbogo, Isiolo Valley, Mlima Nyeusi and Mlima
Nderi areas. Batira had his ranging areas on the western side of the Conservancy but was noted
to shift briefly to the southern (former Manyagalo) area. With the influence of James, he
returned back to Mawingo area where he seemed to have established his home range between
Mutane and Amuri.
Figure 1.9: The ranging areas of four breeding female black rhinos on LWC, 2007 (generated
using kernel homerange analysis in ArcView 3.2)
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Figure 1.10: The ranging areas of five breeding female black rhinos on LWC, January –
September 2007 (generated using kernel homerange analysis in ArcView 3.2)
Figure 1.11: Ranging areas of Mama C and Seiya between January – September and October –
December, 2007
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Figure 1.12: Ranging areas of Ndito and Nashami between January – September and October –
December, 2007
Figure 1.13: Ranging areas of Oboso and Zaria between January – September and October –
December 2007
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Figure 1.14: The ranging areas of Sonia between January – September and October –
December 2007
1.9.
Translocation
No translocations were undertaken during the year. However, three sub adult males; Batira,
Nasha and Sero have reached their adulthood and therefore they should be monitored closely to
assess their interaction with other breeding bulls.
1.10.
Ear notching of black rhinos
In an effort to make all LWC rhinos identifiable by patrol teams and other wildlife management
staff, six rhinos were successfully notched with distinguishable ear patterns in December 2007.
These were Tupac (2.5 years), Mama C (5.4 years), Sonia’s calf 3 (2.2 years), Zaria’s calf 5 (2.0
years), Stumpy’s calf 7 (2.0 years) and Jazz (4.2 years). To date, 44% of the LWC black rhino
population have been ear notched with the current ear notching pattern design while some of the
remaining 56% comprising the founder adults have distinguishable marks based on the old earnotching system. Elimination of clean rhinos has ensured that LWC rhinos are identifiable to all
and helps in gathering reliable biological data for informed management intervention strategies.
1.11.
Recommendations
Ear notching of sub adults rhinos should be an on going exercise in the future as majority of
calves are expected to disperse from their maternal ranging areas once they reach the sub adult
age bracket.
1.12.
Rhino body condition scores
The assessment of rhino body condition followed a 1-5 standardized method as described by
Reuter and Adcock (1998) and adopted by the African Rhino Specialist Group (AfRSG).
Excellent rains received in 2007 resulted to the availability of abundant browse throughout the
year. Consequently, like all the other rhinos, the oldest LWC female black rhino (Stumpy = 39
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
years and Solio = 32 years) which were in their mid lactation period registered an improvement
in their body condition scores (Table 1.4).
Table 1.4: Black rhino body condition scores
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
1.13.
Rhino Name
Zaria
Solio
Natumi
Mawingo
Rhinotek
Ndito
Juniper
Sonia
Samia
Oboso
Nashami
Waiwai
Maxxine
Stumpy
Melita
Lacky
Ibong
Mutane
Borana
Elvis
Tula
Batira
Sex
F
F
F
F
F
F
F
F
F
F
F
F
F
F
M
M
M
M
M
M
F
M
Breeding
condition
Late lactation
Late lactation
Late lactation
Non - lactation
Sub - Adult
Early lactation
Late lactation
Late lactation
Early lactation
Mid lactating
Mid lactating
Mid lactating
Sub - Adult
Late lactation
Adult Male
Adult Male
Adult Male
Adult Male
sub - Adult
Calf
Sub - Adult
Adult Male
Age (yrs)
19.9
32.1
9.4
18.7
6.5
18.1
19.6
16.5
9.4
7.3
9.6
12.6
5.7
39.1
24.1
11.7
20.6
19.1
3.5
2.3
3.8
8.8
Scoring (Jan.
2007)
3
3
3+
3+
4
3+
3
3
3+
3+
3
3
4
3
4
4
4
3+
4
3
3
4
Scoring (Oct.
2007)
3+
3
3+
44
3+
3+
3+
3+
3+
3+
3+
4
3
4
4+
4
4
4
3+
3
4
Performance of white rhino in Lewa
1.13.1. Status of white rhinos in LWC, 2007
The population of white rhino stood at 37 comprising of 8 calves (0≤3 years); 6 sub adults
(3≤6years); 23 adult (>6 years) (Table 1.5; Figure 1.15). The highest proportion of the
population comprised of adults with calves and sub-adults comprising of 21% and 16%
respectively. This was in contrast with the black rhino population which appeared to have a
much younger age distribution. The sex ratio of white rhinos was 1:1 following the translocation
of 5 males and 2 females to Ol Pejeta in 2006 and 2007 in a move meant to correct the disparity
in the sex ratio in the Conservancy that had led to numerous fights among the breeding bulls.
Two births were recorded in 2007 compared to five in 2006. The calves were born to Rinta (3rd
calf) and Ngororika (7th calf). Three females (Murembo, Ngororika and Songare) hold the record
of having brought fourth seven calves each since their introduction into LWC. Four females
follow with five calves each (Figure 1.16). The mean inter-calving interval was 2.5 years with
majority of the females’ last calving interval being 2.0-2.1 years. It is predicted that six females
(including two females (8.0 years) that were moved from Solio to LWC in 2004) will calve in 2008
(Figure 1.17). This prediction is based on the mean inter-calving interval of each respective
female and age at first calving of 7.0 years for first time dams.
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Lewa Wildlife Conservancy
Table 1.5: Sex and age structures of white rhinos on LWC, December 2007
Age class
Males
Females
Not sexed
Sub total
Proportion
population
Calves (0≤1 year)
1
0
1
2
5%
Calves (1<3 years)
1
3
2
6
16%
Sub-adults (3<6 years
unless calved)
4
2
-
6
16%
Adults (6<30 years)
11
11
-
22
59%
Adults (>30 years)
-
1
-
1
3%
Grand total
17
17
3
37
100%
in
Proportion of
population that is
actively breeding
12
10
Sub-total
8
6
4
2
0
Calves
(0≤1 years)
Calves
(1<3 years)
Sub adults
(3<6 years)
Males
Adults
(6-30 years )
Fem ales
Adults
(>30 years)
Uns exed
Figure 1.15: Sex and age structure of white rhinos on LWC, December 2007
8
No. of calves/female
6
4
2
in
ta
R
kw
ai
bi
li
Ja
nd
o
Tu
m
at
al
O
po
N
re
ng
a
ika
So
or
go
r
N
M
ur
em
bo
0
Figure 1.16: Number of calves born per breeding female white rhino in LWC: 1984-2007
1.13.2. Growth rate in 2007
To date, the overall growth rate p.a. of white rhino in LWC has averaged 5%. This rate is set to
increase as more sub adult females are recruited into the breeding age bracket. This is ideal for
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
LWC since stocking rates are still low and there is abundant grass material. Nevertheless, the
increase in numbers can only be accommodated if a balanced sex ratio is maintained.
However, since this species is not indigenous to Kenya, the national Management Guidelines for
White Rhino lay less emphasis on annual growth rates until new sites for releasing excess
production become available. This significantly contrasts with the metapopulation management
of black rhinos that recommends minimum growth rates of 6% p.a. in the well established
sanctuaries in the country.
As such, the main justification for keeping white rhinos in Kenya has been proposed as (OkitaOuma et al., 2007):
- For conservation purposes, where breeding the species supports the reintroduction of
white rhino into original (northern subspecies) range.
- For conservation education due to the high visibility of the animal.
- As a driver for tourism and community conservation initiatives as it is an attractive
species that is relatively easy to manage, thriving on Kenyan grasslands outside of the
trypanosome and tsetse belts.
As for LWC, breeding of white rhinos should be encouraged for the stock to be used as source to
restock other areas including suitable community and private conservancies. To date, ** white
rhinos have been moved out of the conservancy to establish populations elsewhere.
6
6
42
37
5
4
32
33
34
50
1
36
37
40
32
30
3
2
20
Population size
No. of births/deaths/ translocation per
year
Translocation IN
7
1
0
10
2000 2001 2002 2003 2004 2005 2006 2007 2008
Births
Translocated OUT
Predicted births in 2007
Deaths
Population size
Figure 1.17: Trend in white rhino population including births, deaths, translocations in LWC
1.13.3. Sex ratio and translocation
With the removal of five males in 2006 and one sub adult female in 2007, the current sex ratio of
males : females stands at 1M: 1F, 2 with 3 unsexed. This continued balance should be
controlled and surplus males be translocated to other suitable areas.
1.13.4. Overall performance of white rhino on LWC
Since the introduction of white rhinos on LWC, 45 calves have been born. Eighteen animals
have been translocated out to other conservation areas to enhance tourism and for breeding
purposes. The latest movements involved translocation of seven animals to OPC in 2006-2007
as a start towards establishing a viable breeding stock. LWC’s “donor” status of white rhinos in
Kenya can be enhanced if the right sex ratios are maintained.
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
2. GREVY’S ZEBRA RESEARCH AND MONITORING
2.1.
Introduction
In the past few decades, Grevy’s zebra have undergone one of the most significant reductions in
numbers and range of any African mammal. In 2007, the population was estimated to have hit a
low of 1,800 animals (KWS, 2007) down from 15,000 in the 1970’s (Figure 2.1). This represents
an approximate reduction of 88% in just 37 years. Similarly, it is only <0.5% of the Grevy’s zebra
range that is within protected areas including LWC. The factors contributing to these massive
reductions have been discussed in detail by Williams, 2002.
Nonetheless, while the above reductions were occurring, Grevy’s zebra continued to extend their
range southwards into the Laikipia plateau including LWC, where they received sympathetic
reception (Williams, 2002). Consequently, in the past two decades, it is only these areas that
have witnessed increases in numbers (Williams, 2002), the most significant being on LWC.
Presently, LWC holds at least 430 Grevy’s zebra representing an estimated 23% of the global
wild population of this critically endangered species. This figure is up from about 106 animals
that were residing in LWC in 1977. The increase in the Conservancy’s population has mainly
been from births. As a result, LWC’s population has been recognised as one of the three
remaining breeding nucleuses (Rubenstein et al., 2005) in the wild with a potential to increase
and be a source for restocking former rangelands. Numbers in LWC have been confirmed
annually through two major activities:
(i)
Annual game counts conducted since 1977 that showed gradual population increases up
to 1999-2000 when remarkable downward oscillations were witnessed (Figure 2.1). This
is despite the fact that this population resides inside a PA and is free from anthropogenic
factors affecting other populations in pastoralist and livestock dominated areas.
(ii)
Foal patrols that have recorded significant births since 2003 when active monitoring of
natality of foals, their survival and recruitment rates was initiated. Since then, this activity
has been completed on a monthly basis.
700
13718
632
600
12000
500
430
9000
400
300
6000
3000
No. in Lewa
No. in Kenya's rangelands
15000
200
2571
106
2000
1839
0
100
0
1977
1996
1998
2000
2002
Year
Kenya's Rangelands
2004
2006
Lewa
Figure 2.1: Grevy’s zebra population trends in Lewa and Kenya’s Rangelands, 1978-2007
18
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
From above discussion, it is evident that LWC is a critical stronghold of Grevy’s zebra.
Therefore, research and monitoring activities being undertaken in the Conservancy are aimed at
understanding, and subsequently implementing management interventions to ameliorate factors
that may be limiting growth of this population. Furthermore, LWC’s breeding performance can
be used as a benchmark to compare the performance of other populations in pastoralist
dominated areas where competition for critical resources (water, food and space) is more
pronounced. This will provide practical information for decision makers in their pursuit of scaling
greater heights in community based conservation in northern Kenya using Grevy’s zebra
recovery programmes as a flagship tool.
In the past, LWC has collaborated with Earthwatch Institute, St Louis Zoo, Princeton University
and Marwell Conservation in an attempt to explain the above limiting factors. Using appropriate
methods, research and monitoring activities significantly focussed on explaining:
(i)
Inter and intraspecific interaction including competition with Plains zebra; competition
among different reproductive classes of Grevy’s zebra; and predation rates.
(ii)
Mortality of all age classes, natality, survival and recruitment rates of infants.
(iii)
Impact of other biotic and abiotic factors in determining movement patterns, use of
space, and exploitation of food and water resources by Grevy’s and Plains zebra.
(iv)
Susceptibility to diseases and parasitism levels.
In 2007, the specific questions that were addressed by LWC’s Grevy’s zebra research and
monitoring programme focussed on:
(i) Explaining factors limiting the growth of the population of Grevy’s zebra in LWC?
This query required information on births, foal survival and recruitment rates, inter-birth
interval, rate of age specific mortality and causes, and predation rate of both zebra
species. Other factors including competition and parasitism have previously been
addressed and hence were not investigated in 2007.
(ii) Based on the above findings, what practical and relevant adaptive management
interventions should LWC undertake to encourage Grevy’s zebra population growth?
2.2.
Methods
The methods used to address the above questions have been described in detail in past annual
reports (Chege et al., 2007; Low et al., 2005). In particular, the main activities undertaken were:
a) Monthly foal patrols of Grevy’s zebra to determine natality, survival and recruitment rates.
b) Digital identification using a customised database that relied on the unique bar code on the
right rump of Grevy’s zebra. Currently, the reproductive history of about 90% of all adult
Grevy’s zebra has been archived in the database.
c) Daily tracking of collared lions, scat collection and subsequent analysis of hair samples.
2.3.
Results and discussion
2.3.1. Dynamics of Grevy’s zebra numbers in 2007
A total of 430 Grevy’s zebra were counted in the March 2007 total ground and aerial game
census. This was up from 399 animals counted in February 2006. In between the two counts,
there were 69 births and 27 confirmed deaths. At the same time, 29 foals born in 2006 were
confirmed dead between the two counts. Since emigration and immigration through the northern
game gap were not actively monitored and daily reports relied on indirect methods, and while
taking births and deaths between the two counts into account, a total of 439 Grevy’s zebra
should have been counted in the February census.
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
The difference may be explained by the fact that aerial total counts of species only give a
minimal estimate of the population. Minimal emigration and immigration may have had an effect
on overall numbers. Also, not all Grevy’s zebra kills may have been detected due to:
a) The height of grass which made detection of carcasses difficult.
b) Foals in the 0-6 month age bracket may have been consumed whole.
c) Some kills happen at night with hyenas scavenging on the bones before dawn.
2.3.2. Survival and recruitment rates of foals born in 2006
There were 51 foals born in 2006. Eleven and four of these foals were confirmed and suspected
dead respectively by December 2006 through monthly foal patrols. All the suspected dead foals
were subsequently confirmed dead in 2007. Therefore, as at December 2006, there were only
36 foals that were still surviving.
Monthly foal patrols continued in 2007 to determine the fate of the above 36 foals. Fourteen of
them were confirmed dead in 2007. Therefore, only 22 foals (46%) born in 2006 survived to
become juveniles, and hence stood a high chance of survival due to reduced vulnerability to
predation. This overall survival rate was equivalent to 47% that was recorded in 2005 but was
significantly higher than 25% and 27% recorded in 2004 and 2003 respectively (Figure 2.2). It
should however be noted that Rubenstein et al., (2005) have modelled LWC’s Grevy’s zebra
population based on past performances and have shown that in the long term, the
Conservancy’s population will only increase in numbers if the overall survival rate of foals born in
each year is raised above 50%. Therefore, LWC has fallen short of this target since 2003.
2.3.3. Survival and recruitment rates of foals born in 2007
A total of 69 foals were born in 2007 compared to 51 and 75 born in 2006 and 2005 respectively
(Figure 2.3). Nine of these foals were confirmed dead while a further 12 were suspected dead
as at December 2007. Foals were suspected dead if they and their mothers were not seen for a
minimum period of six consecutive months (i.e. last sighting in June 2007), or their mothers were
sighted for two consecutive months without their offsprings. As in the previous years, majority of
the confirmed and suspected dead foals were in the 0-6M age bracket further highlighting the
vulnerability of foals to predation (Rowen, 1992). Therefore, as at December 2007, the survival
rate of foals born in the year was 70% (N=48) (Figure 2.2) majority of which were in the 6-12M
age bracket (Figure 2.4). As in the past, this survival rate is expected to reduce further as
monthly monitoring of foals continue in 2008.
Proportional death and survival
rate
0.80
75%
73%
70%
0.70
0.60
54%
53%
47%
0.50
46%
0.40
0.30
27%
This survival rate is
expected to reduce
further as monthly foal
patrols continue in 2008
30%
25%
0.20
The minimum overall survival
rate of foals born per year
required for Lew a's Grevy's
zebra population to increase
in numbers.
0.10
0.00
2003
Death rate
2004
Overall survival rate
2005
Year
2006
2007
Survival rate as at end of 2007
Figure 2.2: Comparison of survival rate of Grevy’s zebra foals born on LWC, 2003-2007
19
18
No. of foals born per year
Annual Research and Monitoring Report, 2007
75
80
60
Lewa Wildlife Conservancy
69
59
51
44
40
20
0
2003
2004
2005
Year
2006
2007
Figure 2.3: Comparison of Grevy’s zebra foals born annually on Lewa since 2003
No. of foals surving/age bracket
20
40
29
30
20
13
9
10
0
0-3M
3-6M
6-12M
Age bracket of surving foals at end of year
Figure 2.4: Age of Grevy’s zebra foals born in 2007 and still surviving at end of the year
21
2.4.
Seasonality of foaling
In 2007, timing of foaling of Grevy’s zebra was neither synchronised to the rainy seasons in the
year nor in 2006 (Figures 2.5 and 2.6). Rather, foals seemed to have been born throughout the
year with the exception of September, November and December 2007. Elsewhere, it has been
shown that Grevy’s zebra are usually driven into condition dependent oestrus based on
prevailing environmental conditions i.e. they undergo anoestrus in times of dearth of resources
and only reproduce when conditions are right. Therefore, it follows that the high grass biomass
in LWC (even though it becomes moribund in the dry season), coupled by the perennial water
sources, may be enough to trigger and sustain breeding unlike elsewhere in northern Kenya.
19
160
140
120
100
80
60
40
20
0
10
8
6
4
2
p
O
ct
N
ov
D
ec
g
Se
l
Au
Ju
M
Ja
ar
Ap
r
M
ay
Ju
n
0
Rainfall (mm)
Lewa Wildlife Conservancy
12
n
Fe
b
No. foals born per month
Annual Research and Monitoring Report, 2007
Month
No. foals born per m onth in 2007
Rainfall 2007
Figure 2.5: A comparison of numbers of Grevy’s zebra foals born per month on LWC against the
2007 rainfall – note the non-synchrony of foaling with the rains
250
10
200
8
150
6
100
4
50
0
0
M
Fe
b
Ja
ar
Ap
r
M
ay
Ju
n
Ju
l
Au
g
Se
p
O
ct
N
ov
D
ec
2
Rainfall (mm)
12
n
No. foals born per month
22
Month
No. foals born per m onth in 2007
Rainfall 2006
Figure 2.6: A comparison of numbers of Grevy’s zebra foals born per month on LWC against the
2006 rainfall – note the non-synchrony of foaling with the rains
23
2.5.
Inter-foaling interval
Considering that LWC’s Grevy’s zebra reside inside a PA, it follows that this population should
reproduce optimally. Therefore, in 2006, simple inter-foaling benchmarks that were based on the
duration of the gestation period of Grevy’s zebra (= 13.5 months), to assess the females’
reproductive success were developed. These benchmarks were grouped into the following
categories: 13.5-15 months = “Excellent”; while a 24-27 months interval was considered as “Very
Poor”. Similarly, inter-birth intervals >27 months were classified as unknown since females may
have lost a foal in between without being captured in the Portfolio® Database.
All the inter-foaling intervals that have been appropriately captured in the digital database were
re-assessed in 2007. Sixty four percent of the inter-birth intervals were rated above “Average”
with 30% falling within the “Excellent” category i.e. <15.9 months (Figure 2.7). It would be
interesting to gauge the impact of holistic management of grasslands that has been introduced in
20
Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
LWC to assess the response towards reproduction of Grevy’s zebra from the ensuing palatable
and more nutritious grass material that significantly attracts grazers including Grevy’s zebra.
The above benchmarks may be used by other collaborating partners working in northern Kenya
to gauge the level of performance of populations residing in livestock dominated areas (only if
individuals in such populations are known and the reproductive history of females has been
captured appropriately in relevant databases). The output from such assessments may also be
relevant to community based organisations in the region that are in the process of developing
core areas for biodiversity conservation using Grevy’s zebra as a flagship species.
Proportional inter-foaling
interval
0.40
0.30
35
21
0.20
19
19
17
0.10
7
0.00
14-15
Excellent
16-18
Good
19-21
Average
21-24
Poor
24-27
Over 27
Very poor Unknow n
Duration of inter-foaling interval
(Months)
Figure 2.7: Proportional inter-birth intervals for Grevy’s zebra on LWC, 2007
24
2.6.
Distribution of lactating females and foals in 2007
As in the previous years, the central parts of LWC and Ngare Ndare continued to be the
preferred areas where Grevy’s zebra with foals in the 0-3M age bracket formed nursery herds
(Figure 2.8). The distribution of lactating females was observed to be more widespread and
away from water sources, as foals were recruited into the 6-12M age bracket. As in 2006, areas
frequented by the nursery herds were characterised by:
(i)
(ii)
(iii)
(iv)
(v)
Proximity to perennial water sources.
Proximity to the swamp that offered safe drinking water and green herbaceous
material throughout the year.
Abundance of Increaser I and II grass species (Cynodon spp) that are ideal for
production of equid milk (Rubenstein, Pers. comm.)
Relatively open vegetation for enhanced visibility against predation.
Comparatively short grass (hoof level) arising from prescribed burning and intense
cattle grazing; hence the availability of tender and nutritious grass.
In order to imitate the above environmental conditions for the benefit of lactating Grevy’s zebra, it
is proposed that that the annual prescribed burning programme focussing mainly on identified
kindergarten areas should be continued. This should be complimented by intensive livestock
grazing under the holistic management approach that is already in place. The two methods
should ensure: opening up of wooded areas to provide increased visibility; while livestock will
offer greater trampling of moribund grass thus maintaining relative short grass and sprouting of
nutritious herbaceous material preferred by lactating females.
21
Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Figure 2.8: Distribution of Grevy’s zebra foals and juveniles on LWC, 2007
25
22
Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
3. PREDATOR MONITORING IN LEWA
Intensive monitoring of the activities of predators in the Conservancy has been on-going since
2003. The main aim of this exercise is to investigate the impact of predation on prey species
with particular focus to the critically endangered Grevy’s zebra and the more commonly
occurring Plains zebra. Attention has been paid to the long-term implication of predation on the
survival of Grevy’s zebra population in the Conservancy.
The population of Grevy’s zebra in the Conservancy has experienced a downward oscillating
trend dropping from 630 in 2000 to the current population of 430. Factors that could have
potentially led to this reduction in numbers have been investigated in the past with competition
with Plains zebra and predation by lions having been identified as possible limiting factors to the
growth of the population (Figure 3.1). Since the dynamic of lions have changed on a temporal
basis, this project sought to explore further the extent of predation on Grevy’s zebra by lions and
suggest possible mitigation strategies to rectify the situation.
To achieve the above objective, the following activities that have been described in detail in
previous annual reports were completed by gathering and analyzing appropriate data:
(i)
(ii)
(iii)
(iv)
(v)
Collaring of lions to determine spatio-temporal movement patterns. In 2007, two male
lions were collared.
Tracking of lions on a daily basis to determine movements, behaviour and levels of
interaction.
Identification of lions using operational collars as the reference point; and also their
unique whisker spots.
Collection and analysis of scat to determine the proportion of prey hair in the diet of the
target candidates.
Monitoring mortality rates of prey to determine predation levels.
3.1.
Lion profile on LWC as at 2007
The population of lions in LWC stood at 25 resident lions in October 2004 (Njonjo, 2004). This
number reduced to 16 lions by the end of 2005 and to 12 in 2007. Seven cubs were born in
March 2006 while seven males (four sub adults and 3 adults) and a female with her two-year old
cubs emigrated out of the Conservancy in the year. The current resident population comprises
of two adult females, two sub adult females (migrants), one adult male and seven cubs.
3.2.
Collaring, tracking and identification of lions
Since 2003, a number of lions have been fitted with collars. By 2005, six collars were still
operating. However, some of these collars malfunctioned whereas some lions emigrated out of
LWC (2 to Borana Ranch and 3 moved to Samburu Reserve). Therefore, by December 2007,
there was only one female with a reliable collar. This collar served as the reference point during
the daily tracking of lions since the lioness was part of a definite pride. All the uncollared lions
were identified and tracked using spoors that were complimented by Pennycuick and Rudnai’s
method (1970) for individual identification and to determine population sizes.
3.3.
Collection of scat
Scat was collected on a daily basis7 from known lion individuals using the methods listed below
in order to increase the chances of encountering the droppings:
•
•
7
Finding collared individuals and observing them until they produced scat. This was
however time consuming.
Locating the exact areas where lions had been resting and searching for scat once they
had relocated to another place.
Lion scat is difficult to find due to its high protein content thus making it attractive to smaller predators and scavengers.
23
Annual Research and Monitoring Report, 2007
•
•
Lewa Wildlife Conservancy
Kills were located and scat searched around them. This was a very effective way
particularly if the kills were big.
Opportunistically on road sides.
700
25
600
500
20
400
15
300
10
200
5
100
0
0
No. of Grevy's zebra
30
19
96
19
97
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
20
07
No. of lions
3.4.
Scat and hair analysis
The methods used to clean scat and subsequent hair analyses have been explained in detail
(Njonjo, 2004; Chege et al., 2007). As a summary, 20 hairs from each scat sample were
selected for mounting and identification. Only hairs that had a root were mounted on microscope
slides. Hairs were then observed under a light microscope where the basic configuration of the
hair i.e. relative width of the medulla and cortex were used to distinguish between hairs of
different animals. The hairs were similarly compared with a reference hair collection that has
been developed from hairs uprooted from known animals to ensure accuracy.
No. of lions
No. of Grevy's zebra
Figure 3.1: Performance of Grevy’s zebra and lions in LWC, 1996-2007
26
3.5.
Results and discussion
3.5.1. Dynamics of lion population in Lewa
The population of lions in LWC in 2007 remained constant at 12 individuals. Nine of these lions,
comprising of two lionesses and their seven offsprings formed a cohesive group throughout the
year. Two sub-adult females were migrants while 1 male found residence in the Forest.
The dynamic of the lion population has changed by a huge margin since March 2006 when
seven cubs were born. Prior to this, four sub adult males had emigrated to Borana Ranch.
These were subsequently poisoned in 2007 during a wave of poisoning events witnessed in
northern Kenya in 2007. Within the same period, two sub adult females disassociated
themselves with the natal pride in February 2006. Similarly, two and one adult male moved out
of LWC to Samburu National Reserve in July 2006 and April 2007 respectively. Consequently,
as at December 2007, the population of lions in LWC stood at 12 compared to 25 resident lions
that were in the Conservancy in 2004 (Figure 3.2).
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
30
Lion population
25
20
15
10
5
0
2002
2003
2004
2005
2006
2007
Trend in lion population
Figure 3.2: Trend in the number of lions on LWC, 2000-2007
27
3.5.2. Scat and hair analysis in 2007
A total of 38 scat samples were collected and examined for prey hair content in 2007. From
each sample, 20 hairs were individually mounted and observed on a light microscope at x10mg
and x40mg for identification purposes. Results indicated that zebras (56%) formed the main diet
of lions with other species (bovids) contributing only 44% of the diet (Figure 3.3).
Proportion of hairs in lion scat
90
80
70
60
50
40
30
20
10
0
2004
Equids
2005
2006
2007
Other bovids
Figure 3.3: A comparison of the proportion of equids versus bovid hair found in lion scat on
LWC, 2004-2007
28
When hairs from the two zebra species were separated, 30% belonged to Grevy’s zebra while
70% were from Plains zebra (Figure 3.4). The bovids that were mainly predated were Impala,
Eland and Warthog. These results compare well with the field security personnel incident
reports that revealed almost twice as many dead Plains zebra as Grevy’s zebra.
25
Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Proportion of hairs in lion scat
80
70
60
50
40
30
20
10
0
2004
2005
Grevy's zebra
2006
2007
Plains zebra
Figure 3.4: Comparative assessment of predation rates of Grevy’s and Plains zebra from hairs
found in lion scat
29
3.6. Comparative assessment of predation rates, 2004-2007
Based on the scat analysis results dating back to 2004, zebras have continued to form the main
diet of lions although at different magnitudes. The proportions of zebras predated in 2007 (56%)
compared well with 2006 when 59% of the diet of lions comprised of zebra but contrasted with
2004 and 2005 when significantly more equids were predated (Figure 3.3).
This could be a result of emigration of several adult individuals and sub-adults from LWC to
neighbouring ranches and hence the reduction in number of lions to 12 in 2006 and 2007.
Again, up to seven of the lions residing in LWC in 2006 and 2007 were cubs. The highest
predation rate of zebras was in 2004 when both zebra species were predated equally (Figure
3.4). This coincided with the period when LWC had the highest number of lions comprising of 25
residents and up to 10 migrant lions. The lowest rate of predation of zebras was in 2006 and
2007 when the least number of lions were residing in the Conservancy. The highest proportion
of these lions comprised of immatures (7 cubs at a time). During this period, lions appeared to
prefer smaller bodied animals including impala and warthog. This contrasted with 2004 when
majority of the resident lions were adults staying in large group sizes, and hence, they may have
preferred bigger kills to satiate their appetite. This demonstrates the potential benefit that can be
achieved by maintaining the number of lions within the lower limit of acceptable thresholds. As a
start, a population of up to 12 lions (majority being cubs and sub-adults) appear not to
significantly have a negative impact on the population of Grevy’s zebra. .
3.7. Conclusion
The benefit of maintaining few lions on LWC was demonstrated in 2006 and 2007 when the
population of Grevy’s zebra showed an increment in numbers. LWC will need to maintain such
low number of lions in line with the National Strategic Plans and Management Guidelines for
Grevy’s zebra (2007). Similarly, proposals have been made to the Carnivore Working Group of
KWS so that information on predator/prey dynamics can be incorporated in the Lion and Hyena
Management Plan (in preparation).
26
Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
4. TRACKING OF COLLARED GREVY’S ZEBRA IN NORTHERN KENYA
Since mid 2006, LWC has collaborated with Save The Elephants, Princeton University, Marwell
Conservation, Northern Rangelands Trust, Grevy’s Zebra Trust and KWS to monitor the
movement patterns of Grevy’s zebra in northern Kenya. This project relies on GPS/GSM collars
worn by 16 animals that are distributed within the key pastoralist dominated Grevy’s zebra
strongholds of Laisamis, Barsalinga and the Livestock Marketing Division. The initial software
required to download GPS data has been perfected by STE through integration with ArcGIS and
Google Earth for real time outputs and hence more robust analysis.
The collars collect data on the spatial and temporal movements of target animals at regular
intervals (between 30 minutes – 2 hours) as determined by the perceived active/inactive periods
of Grevy’s zebra. It should be appreciated that this is the first time that such detailed and real
time data on movement patterns of Grevy’s zebra in pastoralist areas is being collected in order
to inform management decisions on landscape planning in an attempt to explore ways for
peaceful co-existence of this species with pastoralists and their livestock. This is in line with the
positive and bold steps being undertaken to establish viable community conservation projects in
northern Kenya by various stakeholders.
One set of four animals were GSM collared in Laisamis area (northern most community
conservancy - 150 km north of LWC) in order to provide movement and range use data on this
otherwise elusive population. The Laisamis Grevy’s zebra population is particularly critical since
it has been the least monitored/known and yet it has persisted amidst stiff competition from the
very high densities of livestock in the area. Three of the four collared animals have already
confirmed the extremely large distances that Grevy’s zebra move between the grazing fields and
water (Figure 4.1). In particular, one female made two trips in March 2007 from Laisamis to
Merile through Mt Baio (probably in response to availability of food and water) and covered a
distance of about 280 km in just two weeks (Figure 4.2). Such information will be crucial in
informing decisions about the location of the preferred critical resources both in the wet and dry
season. Also, this information is crucial to the management of Melako, and indeed all other
conservancies in making pragmatic zoning decisions of their areas for future co-existence
between Grevy’s zebra and livestock (Figure 4.3).
In all the collared animals, it would be critical to perform more detailed analysis to determine
factors influencing the movement patterns, including habitats and in response towards the
establishment of core conservation areas especially in West Gate and Kalama Conservancies.
Livestock and predators are important in this venture and hence there is need to combine the
project with other partners working in the region in order to provide such extra data. This need
was realised in a stakeholders meeting in November 2007 held at Mpala where data outputs to
answer these questions and a roadmap for more detailed analysis and reporting procedures for
all users were proposed.
27
Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Mapping by Guy Parker
Figure 4.1: Movement patterns of 3 collared Grevy’s zebra in Laisamis area, Feb. – Jul. 2007
30
Figure 4.2: Movement patterns of one collared female Grevy’s zebra between food and water in
Laisamis area covering 280 km from 1-14 Mar. 2007
31
28
Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Figure 4.3: Movement patterns of Liz (June 2006 – March 2007) showing the extensive
distances travelled by the Grevy’s zebra from the National Reserves to the community areas of
Kalama and West Gate (mapping by Henrik B. Rasmussen)
32
29
Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
5. GENERAL WILDLIFE MONITORING
5.1. Annual game census
LWC’s annual game count was completed in the first quarter of 2007. Annual counts and daily
reports on the abundance and distribution of wildlife are important as they provide trends in the
performance of target species, and assist in formulating informed management intervention
decisions as necessary.
A comparison of the game count figures in 2007 in relation to 2006 and previous counts is shown
in Figure 5.1 and Table 5.1. Analysis of the trends of the key wildlife species indicated gradual
increment in numbers in 2007 compared to 2006. In particular, the population of Grevy’s zebra
rose by 8% while Plains zebra increased by 13% (Figure 5.2). This is encouraging considering
the downward trend observed in the population of the two species since 2001.
The highest gains were realised by eland (47%) (Figure 5.3), ostrich (33%) and oryx (32%)
(Figure 5.4). Giraffe recorded a 29% increase which is quite remarkable considering that this
population was reduced in 2003 when 50 individuals were translocated to Meru Park.
Waterbuck on the other hand showed a 31% reduction (Figure 5.3). However, it is most likely
that several individuals of this species were not sighted due to the thick vegetation experienced
on the valleys and riverine areas after the December 2006 – January 2007 flooding.
50
30
20
10
Grevy's zebra
Burchells zebra
-40
Waterbuck
Warthog
Ostrich
Impala
Giraffe
Grant's gazelle
-30
Elephant
-20
Eland
-10
Buffalo
0
Beisa oryx
Percentage increase/decrease
40
Percentage increas e/decreas e
Figure 5.1: Comparison of the dynamics of some key wildlife species on LWC, 2006-2007
33
30
Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Table65.1: Game count figures in Lewa, 2001-2007
SPECIES
Beisa Oryx
Buffalo
Bush buck
Cheetah
Eland
Elephant
Gerenuk
Giraffe
Grant's gazelle
Greater kudu
Hippo
Hartebeest
Impala
Jackal
Klipsringer
Leopard
Lion
Ostrich
Black rhino
White rhino
Sitatunga
Warthog
Waterbuck
Burchell's zebra
Grevy's zebra
Jan-01
Jan-02
Feb-03
Feb-04
84
86
62
85
49
69
91
125
>20
21
151
150
17
236
162
38
1**
9
627
0
>8
1
8
119
29
30
21
88
149
1264
556
161
>20
10
121
28
15
245
192
37
2**
7
749
0
>8
7
20
98
29
31
23
194
170
1039*
487
203
>20
7
108
157
11
215
167
33
2
4
760
>15
>8
>8
18
65
32
32
16
136
64*
1025
462*
233
>20
8
137
216
7
177
261
36
2
2
679
>12
>6
>8
28
68
36
32
16
129
52
1102
435
255
>20
8
214
297
11
173
258
>20
2
2
836
>12
>8
8
24
48
40
39
14
170
116
1094
448
339
>20
8
169
392
11
147
320
>20
2
2
739
>12
>8
8
16
36
48
36*
14
140
134
970
399
343
>20
5
248
256
~10
189
362
>20
2
2
829
>12
>8
>8
12
48
53
36
10
163
93
1098
430
Species present but not counted
- Spotted hyena
- Dik dik
- Civet cat
- Stripped hyena
- Crocodile
- Serval cat
- Duiker
- Caracal cat
- Genet cat
- Reed buck
- Aardvark
- Steinbok
>
<
~
*
**
0
31
Feb-05
Mar-06
Mar-07
Key
(greater than)
(less than)
(approximately)
(census after translocation out of Lewa)
(census after translocation into Lewa)
(species present but not seen during count)
Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
700
600
1600
500
1200
400
800
300
400
200
Number of Grevy's zebra
Number of Plains zebra
2000
1999 2000 2001 2002 2003 2004 2005 2006 2007
Years
Plains zebra
Grevy's zebra
Figure 5.2: Trend in Grevy’s and Plains zebra numbers, 1999-2007
34
500
Numbers
400
300
200
100
0
1999 2000 2001 2002 2003 2004 2005 2006 2007
Years
Buffalo
Eland
Waterbuck
Figure 5.3: Trend in Buffalo, Eland and Waterbuck numbers, 1999-2007
35
150
Numbers
120
90
60
30
0
1999 2000 2001 2002 2003 2004 2005 2006 2007
Years
Beis a Oryx
Ostrich
Figure 5.4: Trend in Oryx and Ostrich numbers, 1999-2007
36
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
6. ECOLOGICAL MONITORING
6.1. Rainfall in 2007
In 2007, the mean annual rainfall received on the 11 rain stations spatially distributed in LWC
was 620 mm. This amount was slightly lower than the 758 mm received in 2006 but was
significantly higher than 286 mm received in 2006. It was also way above the long-term mean of
513 mm averaged from 1972 to 2006 (Figure 6.1). March – May and October – December were
the rainy seasons. This compared well with the bimodal distribution pattern of rainfall in LWC.
However, all the months (except September) recorded some amount of rain. Sambara station
received the least rainfall (140 mm) while Lewa HQ, Matunda and Soboiga stations with 498mm
each received the highest amount (Figure 6.2).
250
Rainfall (mm)
200
150
100
50
0
Jan
Feb
Mar
2007
Apr
2006
May
Jun
Jul
2005
Aug
Sep
Oct
Nov
Dec
Long term m ean rainfall
Figure 6.1: Monthly rainfall received in LWC (2005-2007) against the long-term mean
37
500
400
300
200
100
0
Le
Su w a
bu
ig
a
M
at
un
d
Ki a
sim
W
es a
tG
a
M te
u
An tu
na nyi
's
h
L e se
pa
L e ru
a
w
a
H
se
L
S a SC
m
ba
ra
Amount of rainfall (mm)
600
Am ount of rainfall (m m )
Figure 6.2: Amount of rainfall received per station in LWC, 2007
38
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
6.2. Vegetation monitoring
Monitoring the status of vegetation in LWC has been an ongoing process since mid-1990s. The
main goal of vegetation monitoring is to provide trends in the condition and performance of both
grass and woody vegetation habitats. The information gathered is important as it guides the
management in making informed decisions including areas suitable for application of prescribed
burning; zones in need of protection as a result of aggravated destruction by elephants - and
hence protection and regeneration of suitable woody vegetation habitats for black rhinos and
other browsers; and blocks to be subjected to intensive cattle grazing.
There were four types of vegetation monitoring activities undertaken in 2007. These were:
1.
Grass assessment
2.
Woody vegetation monitoring
3.
Prescribed burning
4.
Fixed-point photography
6.2.1. Grass assessment
The annual grass assessment survey was completed in order to estimate the biomass of grass
and composition of herbaceous material so as to determine areas that could be subjected to
prescribed burning and intensive cattle grazing. The two methods compliment each other as
they achieve varying results -hence, the method chosen is dependent on the desired output.
The methods used to estimate the biomass of grass are described in detail by Botha (1999). In
particular, any block with grass biomass >5000kg/ha and dominated by increaser I grass species
is considered to be moribund and hence should be considered for prescribed burning.
6.2.2. Prescribed burning
Even though several blocks had grass biomass >5,000kg/ha., only one block was subjected to
prescribed burning in order to remove the moribund stocks of herbaceous material. All the other
blocks were recommended to be subjected to a phased cattle grazing under the holistic
management approach. However, as it will take sometime to attain the desired number of cattle
for meaningful results, in future, grazing will be complimented with cool burns in order to achieve
desired and extensive results. Cool burns are preferred because:
(i)
(ii)
(iii)
They cause minimal damage to the woody vegetation.
Ensure that low biomass of grass is maintained for an extended period of time.
Cause minimal damage to soil nutrients.
6.2.3. Fixed point photography
The major objective of fixed point photography is to monitor trends in vegetation changes over
time. Such changes are brought by varying browsing pressure and changing rainfall regimes.
Fixed point photography was completed in the 28 permanent vegetation monitoring points.
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7. MANAGEMENT ISSUES
7.1. Improvement of rangeland for Grevy’s zebra
7.1.1. Background
In the past several years, the standing crop of grass biomass in LWC has witnessed
considerable build up after the rainy seasons since it is not kept in check by the low densities of
the bulk feeders. These vegetative components comprising mainly of Increaser I8 grass species
(Pennisetum stramineum and P. mezianum) become moribund upon the onset of the dry season
due to extensive underutilisation. The grass species also become highly fibrous, lignified and of
low quality, and hence are not preferred by the grazers.
In the past, one of the management techniques in LWC has been to apply fire to eliminate such
rank grass. Similarly, such burning reduces the risk of fire and changes the composition of grass
species. Even though cool burns have been successfully used in the past, experience has
shown that the rate of success of such intervention on woody species depends on the amount of
rainfall received in the subsequent years. Therefore, the impact on woody vegetation cover and
density has been noted to be remarkably affected when the rains fail. The intended outcome is
exacerbated by the fact that fire is non-selective and covers large areas.
In order to deviate from the above trend, in 2007, LWC adopted part of Allan Savoury’s holistic
management technique for rangeland rehabilitation and restoration that uses large herds of
grazing cattle as a tool. However, grazing may be selective, but this can be overcome if
sufficient numbers of cattle that are confined in space are used. This approach is set to achieve
sustained environmental, economic and social benefits in LWC through:
1. Increasing grazing and wildlife capacity by allowing large herds of community cattle to
graze in defined and controlled blocks.
2. Improving soil health, biodiversity of rangelands and grasslands through removal of
unpreferred grass species while promoting growth of more diverse and palatable grass.
3. Increasing profits and enhancing livelihoods of neighbouring communities by linking them
to better markets for sale of healthy cattle on a trial basis.
The above project has been tied to promoting one of the main objectives of the Conservancy i.e.
long term conservation of endangered species - mainly Grevy’s zebra and black rhino by:
a) Using local community cattle to intensively graze and trample on the moribund grass
material to change the composition and encourage regeneration of quality grasses that
are palatable to Grevy’s zebra. In the long term, extending the rangelands available to
this endangered species thus triggering its population increase.
b) Replacing the rangeland improvement methods currently practiced on LWC (mainly
prescribed burning), with a more environmental friendly technique that will significantly
reduce damage to woody vegetation.
At the same time, the long term implementation of holistic management for rangeland
rehabilitation is meant to replace fragmentary decision-making and short-term solutions with a
system that encompasses a whole, long-lasting process of restoring damaged land and
managing healthy land. Similarly, this technique can be used to restore declining wildlife
populations like Grevy’s zebra – this being the main objective of LWC’s approach.
8
Increaser I species can be defined as grass and herbaceous species which increase when rangeland is under utilised or
selectively grazed.
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Lewa Wildlife Conservancy
The holistic grazing management system as proposed by Alan Savoury is based around the
concept of grass growth, and promoting grazing in accordance with the phases of growth of
grass. These phases are (Felicity, 2007):
•
•
•
Phase 1: Pasture just beginning to grow from seed or root reserves. Energy for growth
coming from the roots. This is the first phase of growth, so there is low pasture biomass
(bulk). Very high nutritional value of the grass. High quality but low quantity grass.
Grazing during this time will cause the plant to have to start from scratch again, calling
on diminished root reserves for energy.
Phase 2: Grass growth really starting to take off. Energy for growth comes from
photosynthesis as there is enough leaf available, good bulk of grass whilst still
reasonably high nutrition levels. Ideal time to graze to balance needs of the grass and
needs of the grazing animal.
Phase 3: Grass lignifies. High bulk of pasture but quality declines rapidly. High quantity
but low quality grass. Plant focuses energy into replenishing root reserves. Grazing at
this stage will not harm the pasture plants but nutritional quality for animals is low.
The basis of Savoury’s grazing system focuses on grazing the pasture plants when in phase two
and allowing a sufficient period of rest post grazing to enable plants to recover and re-grow using
photosynthesis. Constant grazing of an individual plant reduces the leaf area available for
photosynthesis thus the plant must use root reserves to re-grow, weakening its energy reserves
and the capacity of the plant to respond to stress. The grazing system needed to allow plants
sufficient periods of rest and recovery involves a system of rotation, as constant grazing means
individual plants are overgrazed and eventually die out of the system, creating gaps. Presently,
LWC’s grazing programme is geared towards smothering grass that is already in phase 3, with
subsequent progression towards phase 2 and managing grazing at this level in future.
7.1.2. Methods
In order to realise the above objectives, two movable holding pens comprising of 40 metal
frames each, and that can be dismantled to ease portability, were constructed in the year to
confine community cattle grazing in LWC at night. Each frame measured 3x1.8m. The pens
were mounted in identified blocks that had standing grass biomass >5,000 kg/ha. and that were
dominated by the highly fibrous Increaser I grass species that are not preferred by wild grazers.
Previously, extensive studies on rangeland condition in LWC have shown that any block with
standing grass biomass >5,000kg/ha. and that is dominated by Increaser I grass species is
usually moribund and needs to be burnt (Trollope, 1999).
The pens were erected on designated areas that also served as intensive grazing blocks with up
to 800 herds of cattle mainly from the neighbouring communities and those from LWC being
grazed in two tight bunches to maximise trampling and cropping of grass. These herds were
later paddocked and over-nighted in the bomas to again achieve continued grass smothering.
This programme targeted two types of herds:
1. Community cattle coming through LWC for quarantine and destined for the market.
2. Community and LWC cattle for grazing purposes to trample and smoother the grass.
Bomas was shifted/rotated in the same block in a systematic manner (Figure 7.1) in order to
achieve an even smothering effect. In order to attain optimal results, the experimental design
(frequency of pen rotation) was varied severally to suit LWC’s ecological and environmental
conditions. It was realized that for effective trampling, each herd should have at least 500 herds
of cattle and be held in each pen for a minimum of 7 days in the dry season and a maximum of 3
days in the wet season. However, this was dependent on other factors including soil type and
transition between seasons.
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Starting pen
Continue
the shift
r=19.1m
Figure 7.1: Diagrammatic representation of the systematic rotation of cattle pens
39
7.1.3. Results and discussion
Since the inception of the grazing programme, the two pens that occupy 1,146m² each have
been shifted 49 times as at December 2007. Hence, the total area that has been subjected to
intensive trampling and immediate reduction of the standing crop of grass biomass to almost
zero was 56,154 m² compared to the initial biomass before boma erection of >5,000 kg/ha.
(Figure 7.2 and 7.3) This was in addition to intensive trampling and grazing on the blocks.
Completely trampled and manured
area with ~zero grass biomass
Figure 7.2: A section of the cattle pen showing the impact of intense cattle trampling for 5 days
40
There was also significant regeneration of quality and palatable grass in the boma sites as a
result of extensive manuring. This acted as an attractant to grazing herbivores. The sprouting
grass was non-fibrous and un-lignified. It was expected that this grass would attract the lactating
female Grevy’s zebra, and by extension formation of kindergartens in such sites.
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Un-grazed site
Site of cattle pen 1
Site of cattle pen 2
Figure 7.3: A comparison of location of cattle pen sites versus non-pen sites/non-grazed areas
showing the impact of trampling and subsequent phased grass regeneration
41
7.1.4. Impact of the programme and future
Remarkable grassland rehabilitation in terms of trampling and smothering the moribund grass
material, and subsequent regeneration of palatable grass that is preferred by grazers including
Grevy’s zebra, has been realised since the inception of the programme. Similarly, substantial
economic returns to the communities have been achieved through sale of healthy cattle.
Therefore, in future, this programme will remain an integral component of the adaptive wildlife
related management techniques being implemented by LWC.
7.1.5. Recommendations
1. In order to achieve extensive optimal results and suit LWC’s ecological and environment
conditions, at least 4 bunches of community cattle with a minimum of 500 herds per
bunch, should be grazed and paddocked within LWC. This will ultimately increase the
output from intense grazing and trampling as demonstrated in Figure 7.3, and the
subsequent regeneration of quality grass. Such extensive and quality grass lawns are
expected to attract abundant wildlife including the Grevy’s zebra due to the palatability of
herbaceous material. It is hypothesised that provision of such palatable feed will provide
enough nutrients hence improve the health of Grevy’s zebra thus triggering breeding. In
the end, LWC’s vision of restocking the former rangelands of Grevy’s zebra with its
current stock will be realised.
2. Realising a target of 2000 herds of cattle can be achieved through strengthening the
current LWC and Il Ngwesi livestock grazing partnership. Similarly, over time, the option
of bringing NRT affiliate community conservancies on board should be explored and a
partnership agreement developed.
3. However, the use of bomas represents a tiny proportion of the land available. Hence,
there will be need to compliment this programme with the traditional prescribed burning
exercises especially on the P. stramonium dominated black cotton soil areas.
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
7.2. Management of invasive species
Invasive plant species have been known to cause significant threat to water production, natural
landscape and the integrity of biodiversity. Similarly, invasive species always cause ripple
effects to the environment (Foxcrofti et al., 2006). As a result, invasive species are regarded as
one of the greatest threats to global biodiversity. Therefore, such species should be eradicated
using the most convenient techniques to avoid spread.
7.2.1. Invasive and alien species in LWC
There was an unprecedented proliferation of conspicuous invasive species in LWC following the
extremely high rainfall received between November 2006 and January 2007. Concerted efforts
were made to characterize and map these species so as to prioritise elimination. The most
widespread species was Datura stramonium that dominated Willy Robert’s exclusion zone,
Manyagalo Swamp and along Sirikoi River (Figure 7.4) together with most of the disturbed areas
e.g. road drains and abandoned cattle bomas. Willy Robert’s area had previously been
cultivated by the owners of the former Manyagalo Ranch. The area also receives extremely high
run-off of rain water from the adjacent small scale farmers in Manyagalo Community who do not
actively control the spread of invaders unless they are on cultivated land. Of extreme worry is
that even though D. stramonium flourished significantly, it was not utilised by browsers.
Similarly, it was found to prevent growth of grass and other undercover herbaceous material.
Other commonly identified exotic species in LWC included cactus (Opuntia exaltata, O. vulgaris,
Lantana camara and Lippia javanica (Table 7.1). Opuntia was originally meant to demarcate
LWC from the neighbouring communities in the south eastern side. Even though Opuntia is not
currently a major threat on the Conservancy, it appears to be gaining root further from its original
confines and hence need regular monitoring for its timely eradication. Elsewhere in the world
e.g. northern Australia, Opuntia had become a major invasive species that had to be removed
using specially designed eradication programmes (Giesen et al., 2007). L. camara is a major
invasive species in Australia and Southeast Asia and hence the need for its regular monitoring
and eradication to avoid spread.
Table 7.1: Exotic plant species found in LWC as at Dec. 2007 (from Giesen et al., 2007)
Species
Family
Notes
Achyranthes aspera
Amaranthaceae
Originally from China & Australia; common
at Lewa in riverine vegetation
Ageratum conyzoides Asteraceae
Originates from America; in disturbed areas
Chenopodium alba
Chenopodiaceae
Originally from Northern Hemisphere.
Datura stramonium
Solanaceae
Originates from America; in disturbed areas
Galinsoga parviflora
Asteraceae
Lantana camara
Verbenaceae
Opuntia exaltata
Cactaceae
Opuntia vulgaris
Cactaceae
Tagetes minuta
Asteraceae
Originates from South America; in riverine
areas
Originates from South America; disturbed
hill and outcrop areas
Originates from South America; disturbed
places near Lewa boundary, esp. along
roads
Originates from South America; disturbed
places near Lewa boundary, esp. along
roads
Originates from South America; widespread
in many habitats
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
7.2.2. Control of invasive species in LWC
Throughout the year, close collaboration with the Logistics Department was maintained and
majority of the D. stramonium were mechanically removed before the fruiting stage. In 2006, the
following recommendations, that have already been effected, were proposed for adoption and be
maintained in future to ensure timely eradication of invasive species. That in order to realise the
most cost effective results of invasive species eradication, prioritisation for control and ultimately
elimination of the alien species on the Conservancy should to a great extent be guided by the
following four principles (McNeely et al., 2001):
(i)
(ii)
(iii)
(iv)
The current extent of the species in and around LWC needs continuous definition.
This should involve continuous mapping of the distribution and intensity of the focal
species (Figure 7.4).
Documentation of the current and potential impacts to native flora and fauna.
Characterisation of the value of habitats that the species has or may invade.
Available cost effective and efficient measures to control and eliminate the species.
This may involve slashing, uprooting or application of herbicides.
Based on the above guiding principles, the following recommendations were proposed:
(i)
(ii)
(iii)
(iv)
(v)
The existing early detection and monitoring programmes of invasive species in LWC
should be enhanced. Currently, monitoring and control programmes have been ad
hoc. These need to be regularised by the Research and Logistics Departments as
part of their annual work plans.
Regular surveys and monitoring need to be conducted on known infestations and key
areas especially on the former Manyagalo Ranch and Willy Roberts exclusion zone.
To achieve this, permanent belt transects should be placed in infested areas to
measure the rate of spread or otherwise reduction, especially of D. stramonium.
For effective results, D. stramonium and other invasive species should be eliminated
before the fruiting stage. Slashing D. stramonium at the ground level was found to
be effective as it did not necessarily lead to regeneration or coppicing.
Application of herbicides should be considered for extensive stands of invasive
species. Likewise, control actions should be integrated with existing management
plans including controlled burning.
In collaboration with the Community Department, sensitise communities especially in
Manyagalo to eliminate D. stramonium on their land to reduce rates of runoff
especially during the rainy seasons.
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Figure 7.4: Distribution of Datura stramonium on LWC, 2006 – 2007
42
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
7.3. Impact of the Marathon
The annual Lewa Safaricom Marathon entered its eighth year in 2007. Since its inception, the
event has raised substantial funds for biodiversity conservation and human welfare both in the
Conservancy and in northern Kenya. Just like in any other tourism industry, in the recent past,
the event has raised concern for a variety of perceived or actual ecological and social impacts,
including wildlife disturbance and displacement, habitat damage and pollution within the
Conservancy. Much of these impacts may be due to lack of effective management and control
(Roe et al., 1997) due to the size of the event, and therefore, can be regulated if effective
mechanisms for mitigation are put in place.
While all activities carried out during the marathon period are meant to be environmental friendly,
the impact to the environment and wildlife is voluminous. This section is meant to bring into
focus some of the ecological impacts that were witnessed during the 2007 marathon event. The
impacts have been categorised into four: Depletion of resources; pollution; vegetation
degradation and disruption of animal behaviour; and physical impacts.
7.3.1. Depletion of natural resources
The event attracted over 6,000 participants who were distributed in various campsites and action
sites pre, during and post marathon as shown in Table 7.2. Majority of these were
accommodated in the conservancy thus placing a high demand on local resources in order to
satiate participation appetite. Of these participants, an estimated 5,000 found their way into the
finish point while up to 2,000 were at the starting point thus exerting pressure into the fragile
environment. In the campsites:
• Up to 87 fires were lit in just two nights thus exerting pressure on firewood that had to be
collected pre-marathon in the Conservancy.
• Water was extensively utilised during the event for various reasons. This extended to
even watering the marathon route. In the campsites, up to 59 showers were erected to
cater for the huge influx of people.
• Trampling and offroad driving especially in the main campsite areas and the finish point
thus creating a maze of tracks with subsequent creation of bare ground, thus disrupting
the ecological balance.
• Too many vehicles and people significantly reduce the visitor game viewing experience
on the Conservancy’s paying guests.
7.3.2. Disturbance to biodiversity
•
•
The effect on the distribution of wildlife one week to, during and a week after the
marathon. In particular, wildlife species were physically pushed off from all the main
blocks that were traversed by the marathon route. Two zones were identified as having
the most significant wildlife disturbance: (i) critically disturbed zone situated in the central
parts of LWC that was a no go zone to wildlife on the days preceding, and during the
marathon day; and (ii) highly disturbed zone lying within and along the marathon route
where wildlife were physically pushed away on the day of the event (Figure 7.5). This
obviously increased disturbance forcing the wildlife to shift their behaviour in relation to
drinking and feeding patterns. Mapping of the distribution of wildlife was completed one
week prior to the marathon. The same event was repeated one day after the event. The
results were significantly contrasting with majority of the wildlife virtually absent in the
above 2 mentioned zones in the post marathon survey.
Wildlife deaths arising from fences erected temporary around the campsites – at least six
wildlife individuals comprising of 2 Plains zebra, 1 Grevy’s zebra, 2 Impala and a
Warthog have been killed by the temporary fences erected around the campsites in the
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
last three marathons. Similarly, lions appear to have perfected their hunting skills by
chasing their prey against the fences for easy catch.
Mowing of grass on the campsites (e.g. Safaricom village, Digby’s), on water stations,
spectator points and spectator routes adversely affected distribution of wildlife and had
an impact on overall biodiversity within these focal sites.
Impact of having to move the odd dangerous and hand raised animals away from the
Lewa HQs because of the dangers to the marathoners who do not realise that the semitamed animals are not pets. The buffalo had to be moved in 2007 only for it to come
back to the HQs. Sera, the hand-raised giraffe succumbed in 2006 when she twisted
herself in the fence line after been confined in the workshop enclosure.
•
•
7.3.3. Pollution
•
•
•
•
This took various forms. The most significant ones were in the form of air (dust) and
noise pollution. Up to 1,000 vehicles were witnessed during the event majority of which
never adhered to rules and regulations of a protected area. LWC and its affiliate
parties’ vehicles were observed not to follow the well documented and known Lewa
Standard Procedures. There were two helicopters and a spotter plane during the entire
duration of the marathon. At least 10 caravans landed on the airstrip in just two days,
and not to forget other numerous light aircrafts (Table 7.2).
Solid waste and littering – up to 11,400 bottles of water were distributed in just two days
with the subsequent disposal through burying or burning. There were mountainous
loads of garbage generated from the campsites and the finish area that witnessed
temporary markets of all sorts of food items (Table 7.2).
Sewage – up to 123 temporary toilets were erected within the campsite and on the
water points. Along the course, relieve was in the bush.
Aesthetic pollution – this was in terms of tents where up to 531 tents were erected.
There were other numerous one-man tents that were not accounted for, and that were
erected within staff the compounds.
7.3.4. Physical impacts
•
•
•
Roads experienced very high usage with over 1,000 cars gaining entry into LWC in just
two days. This figure excluded LWC and other affiliate parties’ vehicles. The roads
that experienced the highest usage were those linking the Lewa HQs with tourist
outlets, campsites and the main access roads to Matunda (Figure 7.5). These roads
experienced significant impact while delivering supplies, preparing the marathon route
and while spectating.
Construction activities and infrastructural development including too many tents,
showers, toilets etc.
Mowing of campsites and spectator routes.
7.3.5. Compromise in wildlife monitoring activities:
•
At least 56 wildlife (rhino) monitoring teams are usually deployed on a daily basis to offer
security and surveillance of wildlife all over LWC. However, rhino surveillance activities
significantly decrease in the days running up to the event and during the event as most
of the security teams are tied up on security duties at the marathon campsites. This
increases the potential to lose rhino to poachers and indeed all other wildlife.
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Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
Table87.2: Some pertinent data on the impact of Safaricom Marathon
Activity
Self Catering Campsite
Safaricom Village
Maridadi Campsite
VIP Campsite
Highland Campsite
Bomb Campsite
Parliament Campsite
Community Campsite
Security Campsite
Guest to LWC staff
Other Campsites
Water Stops - people who
camped at site
Course
Finish
Start
No. People
350
500
85
100
10
30
20
100
30
250
20
20
150 staff,
1000
spectators
5,000
2,500
No. Tents No. Toilets
100
10
225
50
50
50
10
2
15
6
15
8
8
5
6
2
10
10
2
No.
Showers
10
25
2
6
8
Bush
2
2
Rubbish
Plenty
Plenty
Plenty
Plenty
Yes
Plenty
Plenty
Plenty
Yes
Yes
Yes
12
8
4
Yes
0
20
0
Bush
20, Bush
10, Bush
0
0
0
Plenty
Too much
Plenty
Water
Bottles
500
2,000
1,150
200
200
200
200
100
300
50
No. Fires
30
5
5
5
2
2
2
5
2
10
5
Cut Grass
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Cars
100
50
10
30
3
5
10
10
5
25
4
Planes
Yes
Yes
Yes
Yes
4
Yes
Yes spectator
points
Yes
Yes
8
Yes
200
500
200
2 Helicopters 1
S/Cub
Yes
Yes
1,000
10 caravans in 2
days
6,500
General
0
10
Figure 7.5: Areas that witnessed significant wildlife disturbance due to the Marathon
43
44
Yes
Yes
Yes
Yes
Annual Research and Monitoring Report, 2007
Lewa Wildlife Conservancy
8. REFERENCES
Amin, R., Okita-Ouma, B., Adcock, K., Emslie, R.H., Mulama, M. & Pearce-Kelly, P (2006) An
Integrated Management Strategy for the Conservation of Eastern Black Rhinoceros. Int. Zoo.Yb
40:118-129. Zoological Society of London.
Chege, G., Kisio, E. & Mwololo, M. (2007) Lewa Wildlife Conservancy:
Research & Monitoring Annual Report 2006. Lewa Wildlife Conservancy, Isiolo, Kenya.
Emslie, R. & Brooks, M. (1999) African Rhino: Status survey and action plan. ix + 92. IUCN
Gland and Cambridge, UK. Ix + 92 pp
Foxcrofti, L. C., Lotter, W. D., Runyoro, V. A. & Mattay P. M. C. (2006) A review of the
importance of invasive alien plants in the Ngorongoro Conservation Area and Serengeti National
Park. Afr. J. Ecol., 44:404–406
Giesen, W., Giesen, P. & Giesen, K. (2007) Habitat changes at Lewa Wildlife Conservancy.
KWS (2001) Conservation and management strategy for the black rhino (Diceros bicornis
michaelli) in Kenya (2001 – 2005). Kenya Wildlife Service, Nairobi
Low, B., Chege, G., Kisio, E., Mwololo, M., Kirathe, J., Njonjo, D. (2005) Lewa Wildlife
Conservancy: Research & Monitoring Annual Report 2004. Lewa Wildlife Conservancy,
Isiolo, Kenya.
McNeely, J.A. (2001) The great reshuffling: human dimensions of invasive alien species IUCN,
Gland.
Njonjo, D. (2004) Lewa Wildlife Conservancy Predator Project: Annual Report. Lewa Wildlife
Conservancy, Isiolo.
Okita-Ouma, B., Amin. R. & Kock, R. (2007) Conservation and Management Strategy for the
Black Rhino and Management Guidelines for the White Rhino (2007-2011). Kenya Wildlife
Service, Nairobi.
Okita-Ouma, B., Amin. R., Adcock, K., Emslie, R., Pearce-Kelly, P. & Kock., R. (2007) A positive
turning point in black rhino conservation in Kenya. In Conservation and Management Strategy for
the Black Rhino and Management Guidelines for the White Rhino (2007-2011) (Okita-Ouma, B.,
Amin. R. & Kock, R. (2007). Kenya Wildlife Service, Nairobi.
Rowen, M. (1992) Mother-infant behaviour and ecology of Grevy's zebra, Equus grevyi. PhD
Thesis. Yale, New Haven.
Rubenstein, D., Kirathe, J., Oguge, N., Muoria, P. & Chege, G. (2005) Zebras of Kenya:
Unravelling the relationship between Grevy’s and Plains Zebra. Poster Presented at the Annual
EWI Conference, Boston. U.S.A.
Williams, S.D. (2002) Status and action plan for Grevy's zebra (Equus grevyi). In Zebras, Asses
and Horses (ed. P.D. Moehlman), pp. 11-27. IUCN, Gland, Switzerland and Cambridge.
45
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9. APPENDIX 1: BREEDING PERFORMANCE AND CALVING PREDICTION FOR BLACK AND WHITE RHINO ON LEWA, 1985
- 2007
BLACK RHINO
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Name
Juniper
Mawingo
Meluaya
Ndito
Nyota
Solio
Sonia
Stumpy
Waiwai
Zaria
Nashami
Natumi
Samia
Oboso
Seiya
Tana
Rhinotek
Maxxine
Mama C
Date born
28/6/88
1/6/89
25/1/96
1/1/90
1/12/91
1/1/76
23/8/91
1/1/67
4/7/95
9/3/88
16/7/98
26/9/98
10/9/98
09/10/00
26/4/99
10/10/00
16/8/01
13/6/02
22/7/02
Age
(yrs)
19.5
18.6
11.9
18.0
11.9
32.0
16.4
39.0
12.5
19.8
9.5
9.3
9.3
7.2
8.7
7.2
6.4
5.6
5.4
Mother
Juno
Solio Cow
Juniper
Solio Cow
Stumpy
Solio Cow
Solio
Solio Cow
Solio
Solio
Stumpy
Solio
Sonia
Zaria
Ndito
Stumpy
Juniper
Waiwai
Ndito
Age at 1
calving
(yrs)
85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09
7.6
**
8.4
9.3
7.8
**
7.1
**
6.8
7.8
7.6
6.7
8.2
5.4
5.5
Mean age at 1st calving =
WHITE RHINO
No.
1
2
3
4
5
6
7
8
9
10
11
12
Age
(yrs)
32.0
19.0
27.0
22.0
28.0
22.0
21.0
13.6
8.0
8.0
5.6
5.1
Date born
1/1/76
1/1/89
1/1/81
1/1/86
1/1/80
1/1/86
1/1/87
3/6/94
1/1/00
1/1/00
11/6/02
11/12/02
**
Year female born
Quarter of the year calf born
Future calving based on respective female's last inter-calving interval
Future calving based on respective female's mean inter-calving interval
Expected date of first calving = 7 years)
History unknown
Key
Mother
Solio Cow
Natal Cow
Solio Cow
Natal Cow
Solio Cow
Natal Cow
Solio Cow
Ngororika
Solio Cow
Solio Cow
Natal
Tumbili
Mean age at 1st calving =
46
1
2
3
4
5
6
7
3.2
2.2
1.9
3.2
2.7
3.1
4.7
**
2.1
2.3
2.3
2.8
2.2
2.4
3.5
2.4
3.9
2.3
2.1
2.2
1.7
2.1
1.5
3.9
2.8
3.0
2.3
1.5
3.2
2.2
2.2
1.6
2.1
3.0
-
2.9
2.0
-
2.3
-
Mean inter-calving interval =
7.9
Calving intervals
1
2.9
2.3
2.0
2.3
4.0
2.2
2.2
2.5
Mean
calving
interval/
female
2.5
2.0
1.9
2.5
2.2
3.0
3.6
2.8
2.2
2.4
2.7
2.7
7.3
Age at 1
calving
(yrs)
85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09
6.0
8.1
**
**
**
8.3
9.4
7.7
-
Name
Murembo
Natal
Ngororika
Opondo
Songare
Tumbili
Jakwai
Rinta
Tale
Titilei
Samawati
Schini
Calving Intervals
2
2.6
2.2
2.2
2.6
2.2
3.2
2.9
2.5 -
3
1.9
2.2
2.6
2.5
4.0
3.4
1.9
4
2.8
2.2
2.1
2.5
2.0
3.6
2.1
-
5
1.8
2.1
2.0
-
6
2.0
2.1
2.0
-
7
-
Mean inter-calving interval =
2.5
Mean
calving
interval/
female
2.3
2.2
2.2
2.5
2.7
3.1
2.3
2.5
2.5