Population ecology and distribution of in the Kunene and Erongo Regions, Namibia. June 2004 Dr. P. Stander 16 June 2004

Lions in the arid to semi-arid environment of the Kunene Region live at low densities and maintain large home ranges. In a classic example of adaptation to a harsh environment these lions exhibit unique behaviour, such as individual specialisation and cooperative hunting in Etosha (Stander 1992) and killing seals along the (Bridgeford 1985). Lions are of great aesthetic appeal and financial value due to the growing tourism industry in the Region. Baseline data on density, demography, and ecology of lions collected by this study contribute to our understanding of population dynamics and conservation status. These data are valuable and may be used to guide tourism development, management, and the development of long-term conservation strategies.

INTENSIVE STUDY AREA The study site of 15 440 km2 is situated in the Tourism Concession and extends into the Skeleton Coast Park and surrounding communal conservancies of the Kunene Region. The area falls in the Etendeka Plateau landscape of the northern Desert, with an annual rainfall of 0 - 100 mm (Mendelsohn et al. 2002). The study area stretches from the Atlantic Ocean in the west to the edge of human settlement and livestock farming in the east. The Hoaruseb river runs along the northern boundary and river in the south.

Skeleton Coast Park

Etosha Hoar useb National river Park

Hoanib river Kunene Study Area

Low density High density study area study area % Palmwag

Uniab # river Namibia Lion population ecology in Kunene and Erongo Regions – June 2004 P Stander

METHODS Lions in the Kunene are difficult to locate and observe. To overcome this difficulty all known adult and sub-adult lions are captured and fitted with a radio-collar. The study area is covered systematically by tracking spoor, setting out bait and using sound play- backs to locate and capture individual lions. Radio-collared animals are located with the use of a fixed-wing aircraft. Aerial locations are then followed up by ground observations to record group composition in relation to individuals and age/sex structure, and the ratio of marked to unmarked individuals. Home range analyses are based on locating the daytime resting spots of lions by radio telemetry with at least 24 hours between fixes. Home range size is calculated using the Minimum Convex Polygon (MCP) and Kernel Contour methods (Harris et al. 1990).

RESULTS

Socio-ecology and population dynamics

Since November 1999 a total of 28 lions have been radio collared and 62 lions are marked or individually identifiable. There are four distinct groups or prides of which the Barab/Aub pride is the largest (Genealogy chart). All known adult lions in the Kunene and Erongo Regions were born in the Barab/Aub pride and they have since disperesed permanently from the pride. Two additional sub-adult groups, Xpl-19, 20 & 21 (cubs of Xpl-2) and the first litters of Xpl-9 and 11 (6 lions), have recently left the pride and we are monitoring their movements. The Obab pride, however, appears independent and distinct from the Barab/Aub pride. The Obab pride consists of eight lions but we have substantial evidence that they form part of a larger pride.

Page - 2 Lion population ecology in Kunene and Erongo Regions – June 2004 P Stander

Group structures and genealogy of the Barab/Aub pride and related groups between November 1999 and December 2003.

Barab / Aub Pride

Xpl-1 Xpl-2 Xpl-5 Xpl-9 Xpl-11 Xpl-14 ?

Litter died ? ? ? ? Uniab nomad males ? ? Xpl-19 Xpl-20 Xpl-21 Xpl-4 Xpl-8 Xpl-12

Xpl-13

Hoaruseb group

Xpl-10 Xpl-3 Key: Xpl-6 Adult Female Mortality Xpl-15 Sub-adult Male Sex unknown

Cub ? = Mother unknown

Group structure and genealogy of the Obab pride between March 2001 and December 2003.

Obab Pride

Xpl-17 Xpl-18

One cub died when < 3 months old Xpl-16 Xpl-23 Xpl-22

Page - 3 Lion population ecology in Kunene and Erongo Regions – June 2004 P Stander

Population density was calculated in two intensive study areas (Study site map) that were surveyed intensively and where we were confident that there were no unmarked or unknown lions. We predicted that the western study area would support a lower density of lions since the habitat is significantly dryer and supports lower numbers of prey species than the eastern study area. Using the Kunene Sampling Method (Loveridge et al. 2001) lion densities were calculated at 0.49 lion 100 km-2 for the low density area (west) and 0.71 lion 100 km-2 for the high density area (east). Extrapolating these two density estimates, as a range of minimum to maximum, to the total study area the population estimate is between 76 and 109 lions.

Population demography of Kunene lions Male 2 Sex ratio of Kunene lions Total Study Area (km ) 15440 Female High density study area (km2) 875 2 Low density study area (km ) 770 8 Number of marked / known lions 62 Number of radio-collared lions 28 6 Low High Lion population estimate density density 4

Calculated number of lions 3.8 6.2 2 -2 Lion density (lions 100 km ) 0.49 0.71 0 Extrapolated estimate 76 109 Adult Sub-adult

Of the seven radio-collared lionesses, six (85%) presently have dependant cubs. There are 16 cubs in total at an average of 2.8 cubs per female. The population dynamics of these lions were evaluated over a five year period (1999-2003) by analysing birth rates, mortality, fecundity, and rate of increase associated with 13 known adult lions. This population of 13 known lions in 1998 increased at an average rate of 22.5% (range 14.6 – 34.5%) to 48 lions in 2003, where the sex ratio is even. During the five year period six lionesses gave birth to 13 litters totalling 38 cubs. Litter sizes ranged between 2 and 5 cubs with the mean at 3.1 cubs. Cub survival was high, with only 9% mortality up to age of one year (n = 38) and none thereafter. With most cubs surviving, the mean birth interval was 2.2 years (SD = 0.28; range 1.9 – 2.7 years; (n = 6).

Distribution of age classes in the Kunene lion population

16

14

12

10 R2 = 0.9739 8

Numbers 6 4

2

0 Small cubs Large cubs (1- Sub-adults (2- Adults (4-10yrs) Past prime (<1yrs) 2yrs) 4yrs) (>10yrs)

Age Classes

Page - 4 Lion population ecology in Kunene and Erongo Regions – June 2004 P Stander

With this remarkably high fecundity rate there is a preponderance of young lions in the population when looking at an age distribution graph for 2003. However, when the same data is cast into broader age classes the result depicts the characteristics of a healthy and stable population.

The phenomenal increase of this lion population during the study period is best presented as a logarithmic rate of increase (top) and the annual exponential growth rate (bottom). Population growth was over 30% for both 1999 and 2000. Thereafter it dropped to around 15% for 2001, 2002, and 2003.

The rate of increase of the Kunene lion population

4.00 3.50 y = 0.6945 x - 1387.4 3.00

2.50 2.00 Numbers e 1.50

log 1.00

0.50 0.00 1999 2000 2001 2002 2003 2004 Time (years)

Exponential rate of growth of the Kunene lion population

0.45

0.40

0.35

0.30

0.25

0.20

0.15

increase of rate Exponential e 0.10

log

0.05

0.00

1999 2000 2001 2002 2003

Years

Page - 5 Lion population ecology in Kunene and Erongo Regions – June 2004 P Stander

Dispersal and expansion of the Kunene lion population

The highest concentration of lions (core area) in the Kunene region is found in the Palmwag Tourism Concession, between the Hoanib and Uniab Rivers. Northern and southern home ranges adult female Xpl-10 Home range of adult female Xpl-9

14—20' 12—30' 13— 13—30' 14— 13—20' 13—40' 14— 14—20'

r 19—20' 18—30' ive nib r H oa

19—20' 18—30'

# # #Purros # # # # Aub river # # # # # # # # # ## Hunkab# # # # ### # 19—40' # 19— # # # # #

# # #

k # # # r

19— # a # #

# # # Sesfontein 19—40' # #

% P

# # ### # Hoaruseb # t Kai-as # ##

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#H o # # Project % # e # l

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S Palm

# Obab 20— # # # # ##### Hoanib river # #Aub river river # # 20— 19—30' Hunkab# # # #

# #

k Kaikams

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t Kai-as

s # v er

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S Palm Obab 20— river 20—20'

20— #Kaikams

r i v er 20—20' Uniab Uniab river

12—30' 13— 13—30' 14— 13—20' 13—40' 14— Home range of adult female Xpl-18 Home range of sub-adult group Xpl-4 14—20' 13—20' 13—40' 14— 14—20' 14—20' 13—20' 13—40' 14— 14—20'

19—20' 19—20' iver iver nib r nib r H oa H oa 19—20' 19—20'

# Aub river Aub river # ## ## Hunkab# Hunkab# 19—40' 19—40' # # #

#

k

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19—40' # P P #

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S # ## Palm # # Palm 20— Obab 20— Obab # # # ## # ## ### river river # # # #

20— # 20— # # # # ### ## # # ## # # # # #Kaikams #Kaikams# # # # ### r iv er r iv er Uni ab Uni ab

20—20' 20—20'

20—20' 20—20'

13—20' 13—40' 14— 13—20' 13—40' 14—

Page - 6 Lion population ecology in Kunene and Erongo Regions – June 2004 P Stander

The dispersal patterns of six groups of lions have been monitored since the late 1990’s. All the groups, with the exception of the most recent dispersal (Xpl-19 group), have settled in a new home range. With the exclusion of the Xpl-19 group, the lions moved an average of 104.6 km (SD = 30.8) from their maternal home range.

Dispersal of Kunene lions from their maternal home ranges Date occupying Direct distance Group Lion ID maternal home to present home composition range range (km)* Xpl-1 Adult male 1998 120 Xpl-5 & 9 Adult females 1998 85 Xpl-3,6 & 15 Adult males 1999/2000 130 Xpl-10 Adult female 1999/2000 128 Xpl-4,8 & 12 Adult males 1999/2000 60 Xpl-19,20 & 21 Sub-adults 2001 51 *Present home range is defined as the area occupied between January and July 2003.

#Purros Etosha National Par k Xpl- 3

Xpl- 10 Sesfontein% Xpl- 1 Hoaruseb river r riv e ni b Ho a Xpl- 5,9 Mowe% Bay Xpl- 19 Hoanib river

Hunkab# Xpl-3,4,10,19

k

r

a Aub river

P

t Aub Canyon s Kai-as #

a # o

C

n

o Li o n

t % Xpl-1,5&9

e Proj ect l %

e Camp k Palmw ag

S Ob ab river # Xpl- 4 Kai kams b r iver Uni a Uniab Key river

Maternal home range

Home range during 2003

Page - 7 Lion population ecology in Kunene and Erongo Regions – June 2004 P Stander

With the rapid growth of the lion population in the core area between 2000 and 2003, the dispersal of individual lions and hence the expansion of the population is to be expected. During the later half of 2003 and in 2004 we have documented several events of dispersal and population expansion. Marked lions from the core population moved north and settled in the Hoanib and Hoaruseb Rivers. During late 2003 and early 2004 some individual lions also moved south to the Hoab and Ugab Rivers, and one individual has moved as far south as the Omaruru River.

Developing conservation strategies for the Kunene lions is, among many ecological parameters, dependent on a sound understanding of the factors that drive the distribution and dispersion of the population. Monitoring the dispersal of individuals from their maternal home ranges provides important information towards understanding these population characteristics.

Page - 8 Lion population ecology in Kunene and Erongo Regions – June 2004 P Stander

CONCLUSION This desert adapted and coastal roaming lion population were believed to have disappeared totally after a low rainfall period in the 1980’s when many were killed by pastoralists. This study therefore unveils significant features and characteristics of the population. These lions live in the most rugged and arid environment anywhere in Africa. Some aspects of their behaviour and ecology is markedly different to lions elsewhere. Under these low density conditions Kunene lions produce larger litters (3.1 cubs) than measured elsewhere in Africa (2.4 cubs, Schaller 1972), and cub survival is unusually high. These features contributed to an astounding growth-rate, population increase, and subsequent expansion.

REFERENCES Bridgeford, P.A. (1985). Unusual diet of the lion Panthera leo in the Skeleton Coast Park. Madoqua. 14: 187-188. Harris, S., Cresswell, W.J., Forde, P.G., Trewhella, W.J., Woollard, T. & Wray, S. (1990). Home-range analysis using radio-tracking data - a review of problems and techniques particularly as applied to the study of mammals. Mammal Rev. 20: 97-123. Loveridge, A. J., Lynam, T. and Macdonald, D.W. (Eds). (2001). Lion Conservation Research. Workshop 1: Survey Techniques. Wildl. Conserv. Unit. Pp: 2-4. Mendlesohn, J., Jarvis, A., Roberts, C. & Robertson, T. (2002). Atlas of Namibia : A portrait of the Land and it’s People. David Philip Publishers, Cape Town. Schaller, G.B. (1972). The Serengeti Lion. Chicago: University of Chicago Press. Stander, P.E. (1992). Cooperative hunting in lions: the role of the individual. Behav. Ecol. Sociobiol. 29:445-454.

ACKNOWLEDGEMENTS The Kunene Lion Project received financial support and assistance from the Ministry of Environment and Tourism, Namibia Nature Foundation, Fort Worth Zoo (USA), Dunlop (Namibia), Total (Namibia), IRDNC, WWF - LIFE Program, Brookfield Zoo (USA) and Wilderness Safaris. Field data were collected by P Stander and L Conradie, with assistance from P Haredoep, W Moller and M Witbeen. The Ministry of Environment and Tourism is thanked for their support.

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