A juvenile Martial with kill on the Lewa-Borana Landscape

LEWA-BORANA LANDSCAPE WILDLIFE COUNT REPORT 20 MARCH 2020

Timothy Kaaria, Edwin Kisio, and David Kimiti

1.0 Introduction The Lewa-Borana Landscape (LBL) is a combined conservation area made up of Lewa Wildlife Conservancy and Borana Conservancy. The Landscape has been conducting annual wildlife counts using aerial and ground counting methods for many years. The two Conservancies begun wildlife counts in different years. Lewa’s counts dates back to 1977 while that of Borana started in 1991. The first combined count in the Landscape was conducted in 2016 and has been maintained to date.

The annual wildlife count is necessitated by the need to understand the general status and trends of wildlife populations in response to variations in , as well ecological and environmental conditions and species interactions.

The main objectives of the annual wildlife count are to:

1. Determine species abundance. 2. Derive and compare past and current species population trends. 3. Propose conservation priorities.

2.0 Methodology In 2020, the wildlife count on LBL combined both the aerial and ground counts. This count was conducted from 7.00 am to 12:00 pm on the 3rd and 4th March 2020. Heavy rains were received on the eve of the count on the Borana side of the Landscape which necessitated the activity being conducted in two days as opposed to one day in previous years. Thus, the count on the Lewa section of the landscape was conducted on day one while the Borana section was completed on day two.

The Landscape was divided into eight ground counting blocks and eight aerial counting blocks (Figure 1). The blocks were demarcated by either roads or other geographical features, primarily rivers, valleys and hills. On each ground counting block, wildlife species were counted by a minimum of three observers using one vehicle that traversed all the roads counting all seen on the way. All the wildlife sightings were recorded using a Cybertracker1 enabled PDA. In addition, hand-written data sheets of the same sightings were completed to act as a back-up in case the Cybertracker malfunctioned.

The blocks that were counted from the air had relatively poor accessibility and reduced visibility from the ground.

The aerial counting blocks were counted using a PA–18 Supercub (blocks 9a-9e) and a Cessna 180 aircraft (blocks 9f-9h) flown at an average height of 300 feet above the ground level. The speed of the aircrafts varied from 70 – 85 knots. As much as possible, transects were maintained at 500-metres on either side of the aircraft and followed an east - west or north - south direction depending on terrain, and the direction of wind and sun. The aerial counting team on the Lewa section used a dictaphone to record observations and a GPS unit to record geographic position data for mapping. The voice data was then downloaded onto a computer and transcribed onto a Microsoft Excel spreadsheet. Data from GPS unit was also downloaded for mapping.

The Borana section used datasheets to record observations and a GPS unit was left running to record tracklogs for mapping.

1 Cybertracker is a software that uses a geographic positioning system (GPS) enabled personal digital assistant (PDA) such as smartphones to collect GPS data and wildlife observation data in a single unit.

Figure 1: Map of the LBL showing the ground and aerial wildlife counting blocks, March 2020

3.0 Results and discussion The summary of wildlife sightings from the ground blocks and aerial blocks were added together for every wildlife species encountered (Table 1). We also produced the wildlife distribution map (Figure 2), patrol effort map/track logs (Figure 3), wildlife trends (Figure 4), and distribution maps of selected wildlife species (Figure 5a & b). The trends for most of the main wildlife species indicate an increase in numbers between 2018 and 2019 (Figure 4). In particular, Buffalo (χ2 = 276.94, df = 4, p = 0.0001), Beisa oryx (χ2 = 49.68, df = 4, p = 0.0001), (χ2 = 31.808, df = 4, p = 0.0001), Grevy’s zebra (χ2 = 2.8814, df = 4, p = 0.5779), and Plains zebra (χ2 = 84.362, df = 4, p = 0.0001) are increasing. Giraffe exhibited a decreasing trend (χ2 = 74.442, df = 4, p = 0.0001), as did Eland, although to a lesser degree (χ2 = 37.12, df = 4, p = 0.0001). The population of Grants in Borana section doubled while that of Lewa section increased substantially. While a highly productive population as a result of abundant rains in late 2019 may have played a large role in these increased numbers, our hypothesis is that there was a large influx of new individuals from outside the Landscape through the eastern gaps on the Borana fence line. Immigration of Hartebeest from Ole Naishu Ranch into Borana may also have occurred in the year thus boosting this population. In summary, populations of most wildlife species on Lewa are increasing or stable. The only populations of concern at the moment are the Reticulated giraffe which are decreasing and Buffaloes which continue to increase significantly. Monitoring of these two species will continue to identify any internal drivers for the dynamics as well as identify any possible management interventions. For more details on the number of wildlife counted on each property (Lewa and Borana Conservancy) against the previous years, refer to Appendices 1 and 2. It should be noted that the numbers of some specific wildlife species presented in each appendix e.g. Elephants, Buffaloes and Plains zebra should not be referenced on their own as these wildlife cross from Borana to Lewa side and vice versa depending on availability of resources. Thus, Table 1 is more accurately a representative picture of the status of wildlife across the entire Landscape.

4.0 Conclusion and recommendations Buffalo, Hartebeest, and Grant’s gazelle are rapidly increasing. The cause of increase for the first two is primarily through births as seen in our monthly surveys. Hartebeest on the Borana side may also have increased from immigration. However, little is known for the cause of increase in Grant’s gazelle population. It is therefore recommended that we monitor the use of all migratory corridors using camera traps on the Borana section of the Landscape to understand their usage by wildlife. Additionally, aerial counts should be standardized by limiting surveys on both sections of the Landscape to use of the PA-18 Supercub aircraft which can achieve slower speeds. To mitigate non-availability of two Supercubs at the same time, the count can be done over two days using one Supercub.

Figure 2: A combined distribution map of all wildlife sightings, March 2020

Figure 3: Patrol effort map/track logs during the wildlife count, March 2020 Table 1: Wildlife numbers counted on Lewa–Borana Landscape, 2016 – 2020

Lewa - Borana Landscape Wildlife Count Dates: 2016 - 2020 SPECIES 2016 2017 2018 2019 2020 Beisa Oryx 179 220 178 227 307 Buffalo 1220 1391 1623 1753 2086 Bush buck 15 17 16 15 15 8 1 4 5 6 Eland 280 192 322 291 245 Elephant 416 509 250 253 727 10 10 11 10 10 Gazelle, Grants 348 443 415 718 1101 Gazelle, Thompsons 27 4 7 10 16 Giraffe 273 251 127 167 178 Greater kudu 28 35 22 32 32 Hippo 2 2 2 2 2 Hartebeest 30 62 64 64 93 Hyena, spotted 0 0 122 133 136 1113 1096 1763 1817 1505 (Silver backed) 9 12 6 7 14 8 8 8 8 8 7 8 9 9 9 17 44 45 47 53 51 44 41 52 65 Rhino, black 81 82 88 101 109 Rhino, white 70 75 80 87 97 Sitatunga 0 0 0 0 0 68 85 140 161 168 Waterbuck 136 168 152 180 167 Zebra, Burchell 1262 1236 1228 1484 1599 Zebra, Grevy's 299 292 308 313 331

Notes Numbers correlated with daily sightings from patrol reports Known population Number derived from the unique IDs of Grevy’s zebra from the IBEIS database from October 2017 to Mid-January 2018 Repeat count on 11th Apr 2018; 12th Mar 2019

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Buffalo - Lewa Beisa oryx - Lewa Hartebeest - Lewa Eland - Lewa 2000 200 120 500 100 1500 150 400 80 300 1000 100 60 Numbers Numbers 200 Numbers 40 Numbers 500 50 100 20 0 0 0 0

Year Year Year Year Buffalo - Borana Beisa oryx - Borana Hartebeest - Borana Eland - Borana 800 150 60 150

600 100 40 100 400

Numbers 50

Numbers 50 Numbers Numbers 20 200 0 0 0 0

Year Year Year Year Giraffe - Lewa Plains zebra - Lewa Grevy's zebra - Lewa 800 2000 800

600 1500 600

400 1000 400

Numbers 725 Numbers Numbers 200 500 200

0 0 0

Year Year Year Giraffe - Borana Plains zebra - Borana 100 1000 80 800 60 600 40 400 Numbers Numbers 20 200 0 0

Year Year Figure 4: Wildlife trends of selected species on LBL - 2020

Figure 5a: Wildlife distribution maps of selected species on LBL - 2020 9

Figure 6b: Wildlife distribution maps of selected species on LBL - 2020

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Appendix 1: count figures on Lewa Wildlife Conservancy: 1977 – 2020

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Appendix 2: Game count figures on Borana Wildlife Conservancy: 1977 – 2020

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