The re-establishment and management of a lion Panthera leo population in Zululand, South Africa

The re-establishment and management of a lion Panthera leo population in Zululand, South Africa

Biological Conservation 19 (198(~81) 107 117 THE RE-ESTABLISHMENT AND MANAGEMENT OF A LION PANTHERA LEO POPULATION IN ZULULAND, SOUTH AFRICA J. L. A...

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Biological Conservation 19 (198(~81) 107 117

THE RE-ESTABLISHMENT AND MANAGEMENT OF A LION PANTHERA LEO POPULATION IN ZULULAND, SOUTH AFRICA

J. L. ANDERSON Natal Parks, Game and Fish Preservation Board, UmJblozi Game Reserve, PO Box 99, Mtuabtuba 3935+ South AJ?ica

ABSTRACT

The re-establishment of a viable lion population in an area from which the)' had been eliminated is described. Subsequent growth of the population with associated dispersion and stock killing is documented. The rationale behind, and results oj~ a management programme to maintain a viable lion population with an acceptable level of stock killing are discussed.

INTRODUCTION

Large carnivores are generally regarded as being incompatible with man and his domestic animals. This is aptly illustrated by the recent dramatic changes in the distribution of the lion (Guggisberg, 1962; Schaller, 1972). There is little doubt that the endemic lion population in Zululand was actively eliminated, primarily by white settlers and hunters. These lions were last reported in central Zululand in 1938 by Steele (1970), who described the arrival in 1958 of a male which walked down from Mocambique and took up residence in Umfolozi Game Reserve. The initial and unofficial attempt to re-establish a viable population in the Umfolozi Game Reserve was made in 1963 with the introduction of a tame lioness. This was a failure, but a second project in 1965, when two wild females and three cubs (one male, two females) were introduced from the Transvaal, was successful. The fact that a litter was born indicated that these animals had settled down well. The population continued to increase and in 1968 three sub-adult males left Umfolozi, moved northwards through the corridor of state land into Hluhluwe Game Reserve and then out on to nearby cattle ranches. There they killed livestock valued at approximately £500 before they were shot. As the lion population increased so did the dispersion of lions and numbers of livestock killed. The costs of compensation paid to farmers was borne by the 107 Biol. Conserv. 0006-3207/81/0019-0107/$02"25 © Applied Science Publishers Ltd, England, 1981 Printed in Great Britain

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J. L. ANDERSON

Provincial Government and staff from the game reserves spent an increasing number of man-hours hunting the stock killers. In 1970 the first corrective measures to limit movement from the area were applied. The 1.5 m-high perimeter fence was reinforced with wire mesh but this proved ineffective. Subsequently, in 1972, it was decided that the height of this fence should be increased to 2 m and that this should be meshed, the netting buried 0.5 m below the soil surface. A further corrective measure was that any lion seen within 400 m of the fence would be shot and a predator control team was established to destroy any lion outside the area. During 1973 the policy of destroying lions near the boundary fence was implemented while improvements to the fence began. These measures still proved to be ineffective since during that year the number of cattle killed reached a peak (83). It was then decided that research into the problem was needed in order to establish alternative and effective means of reducing the livestock losses while maintaining as high a lion population as possible. This paper elaborates orr Steele's (1970) earlier description of the population and describes the measures taken to solve the problems of dispersion and stock killing. THE STUDY AREA

The Umfolozi and Hluhluwe G a m e Reserves and interconnecting corridor have an area of about 96,000 ha (Fig. 1). This complex, which is managed as a unit by the Natal Parks, G a m e and Fish Preservation Board (NPB), lies in the Lowveld vegetation type (Acocks, 1953). The t o p o g r a p h y is hilly with intersecting drainage lines and the altitude ranges from 60 m to 650 m above sea level. The major habitats vary from moist semi-deciduous forest in the north of Hluhluwe to open savanna woodlands in the south of Umfolozi. Most of the area is covered with a wooded savanna interspersed with patches of secondary scrub thicket. Perennial surface water is available on the major river systems and ephemeral streams and waterholes often retain water until well into the dry season. Probably because of the good water distribution ungulates are fairly evenly distributed (Bourquin et al., 1971). Their biomass is as high as 80 kg/ha and individual species range in size from square-lipped rhinoceros Ceratotherium simum down to blue duiker Cephalophus monticola. METHODS

Census The topography and vegetation cover of the area are such that most of the fieldwork had to be done on foot. The banks of major watercourses and the sandbanks on the rivers were examined for lion tracks as frequently as possible. As

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these provided a wide coverage of the area, a general picture of lion distribution was obtained. During the cooler months (May to August) lions favoured the river sandbanks when lying up during the day and there they could be readily stalked, counted and classified into sex and age classes. Over this period flights in a helicopter following the course of the river at a height of about 100 m and speed of 110 kph proved productive. In this manner up to 35 lions were located and classified within 1.5h. Capture and marking It was necessary to recognise individuals to determine the extent of pride areas, to reduce the chances of duplicate counting of groups or prides and to obtain an idea of the areas and prides from which dispersal occurred. The method of individual recognition described by Pennycuick & Rudnai (I 970)could not be applied as the animals would not permit one to approach close enough to record the whisker pattern. Using an amplified tape recording of lions and hyenas feeding, lions were attracted to a carcase using a variation of the technique described by Smuts et al. (1977, 1978c) or by placing a carcase near a favoured lying-up site. In each case the carcase was tied to an immovable object. Because of their shyness during the day lions were darted at night either from a vehicle or a seat fixed in a tree. Only animals older than about 18 months were immobilised and a standard dose of 200mg Phencyclidine. hydrochloride (Sernylan) (Bio-Ceutic Laboratories, St Joseph, Missouri, USA) and 10mg Acetylpromazine maleate (The Boots Co. Ltd, Nottingham, England)was used for all animals. For aesthetic reasons marking with individually recognisable collars or eartags was limited to one or two animals in each pride. For this reason only 20 animals were marked and once sufficient data had been collected these were recaptured and the eartags or collars removed. Brochures in which the project was described, and containing a map, were distributed to visitors who were asked to help in the resighting of marked animals. The collated sightings of marked animals helped determine which individuals and groups belonged to which prides and to define the pride area boundaries. Age classification Field age classifications were made on the basis of body size in relation to the size of an adult female. In the case of males which exceeded this size mane development (Smuts et al., 1978a) was used. The ages of lions which had left the complex and had been destroyed were estimated by using skull measurements and data on tooth development as described by Smuts et al. (1978a). Numerical status By the end of 1974 it became obvious that the minimum known population (114) was almost twice that of previous estimates (N PB records). The minimum known

RE-ESTABLISHMENT AND MANAGEMENT OF A LION POPULATION IN Z U L U L A N D

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population at the end of each year between 1965 and 1978 and the cumulative total of all lions destroyed over that period is illustrated in Fig. 2. The population estimates between 1965 and 1968 have been extracted from NPB records of sightings of known groups and those between 1970 and 1973 are based on the numbers counted in the annual game censuses (Vincent, 1970; Hitchins, 1971, 1972, 1973). The data from 1965 to 1968, when the population was comparatively small and very few animals had been destroyed, was considered accurate enough to use in calculating the rate of increase. Following the method used by Grimsdell & Bell (1972), r between 1965 and 1968 was found to be 0.43. 200' 190' 180'

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Estimates of the lion population and the cumulative totals of all lion destroyed over the period 1965-78.

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Distribution Resightings indicated that the population could be grouped into eight prides. Pride areas were situated along the major river systems, the number in each ranging from 4 to 24 animals.

Dispersal and movement from the complex The sex and age classes of lions destroyed beyond the boundary fence were recorded (Table 1). Animals less than 20 months old, destroyed with adult females, have not been included in this table as I do not believe their movement from the area was an independent one. During the first four years in which animals left the area only sub-adult males were involved. The first year in which females left the area was in TABLE 1 THE NUMBERS OF SUB-ADULT MALES AND SUB-ADULT AND ADULT FEMALES DESTROYED BETWEEN 1968 AND 1978 OUTSIDE TIIE HLUHLUWE/UMFOLOZI/CORRIDOR COMPLEX

Year

Males

Females

1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978

3 3 0 7 12 13 12 3 4 0 2

0 0 1 I 2 3 I 2 8 0 2

Total:

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20

Significance of difference Not Not Not Not p < p < p < Not Not Not Not

significant significant significant significant 0.01 0.025 0.005 significant significant significant significant

p < 0.001

1972. This was an adult female and she was destroyed less than 1 km from the boundary. The first dispersion of sub-adult females in the c o m p a n y of similarly aged males occurred in 1975. Significantly (p < 0.001) more males left the area than females. The shortest distance between the site where an animal was destroyed and the complex boundary fence was determined from a 1 : 50,000 map. Males were found (23-2 + 9.9km; ~ + 2SE, n = 59) significantly (p <0.01) further from the boundary than were females (0.6 _+ 0.4km; ~ _+ 2SE, n = 20). Not all skulls of animals destroyed outside the complex were recovered. However, in the age distribution of those that were (Table 2), the males were between 18 and 42 months old with a peak at between 25 and 36 months. Females ranged from 18 months to over five years of age. Sub-adult males, once having left the complex, seldom if ever returned. In contrast there have been many (n > 50) instances where females with cubs have left and returned almost immediately.

RE-ESTABLISHMENT AND MANAGEMENT OF A LION POPULATION IN ZULULAND

113

TABLE 2 AGE CLASS DISTRIBUTION OF 24 MALEAND 12 FEMALELIONS DESTROYEDOUTSIDE THE HLUHLUWE/UMFOLOZI/CORRIDOR COMPLEX

Age class (months)

Males

Females

7-12 13-18 19-24 25-30 31-36 37-42 43-48 49-54 55-60 61-66

0 1 4 9 6 5 0 0 0 0

0 0 0 3 5 0 2 2 0 2

DI SCUSSION

The rate of increase of the lion population over the first years of its reiniroduction (r = 0-43) exceeds that recorded in endemic populations (Schaller, 1972; Rudnai, 1973; Smuts, 1978a). This high rate of increase may be attributed to several factors which, although they may not have influenced natality, probably aided cub survival. The area being colonised contained no resident lions and consequently social factors which might have inhibited the rate of increase (Bertram, 1975) were absent during this initial period of population growth. This situation bears similarity to that in the Kruger National Park where there was a rapid increase in lion numbers following an experimental cropping programme (Smuts, 1978a). Within the complex, none of the prey species is migratory. Food supply for lions resident in prides is therefore constant throughout the year, a feature which Bertram (1973) has shown to be important in influencing cub survival. The herbivore biomass in Umfolozi shortly after the introduction of the females was 7660 kg/km 2 (Melton, 1978). This was considerably higher than the 5400kg/km 2 expected by the relationship of rainfall: biomass shown by Coe et all (1976). With rhinoceros and giraffe excluded from this biomass figure, as they rarely fall prey to lion, the available prey ungulate biomass in Umfolozi was at least 3758 kg/km 2. Based on the annual census figures and conservative estimates of those species which were difficult to count, the ratio of prey animals per lion (including small cubs) has not been less than 270:1. This far exceeds similar ratios from the central Kruger National Park 110:1 (Smuts, 1978a), Nairobi National Park 180:1 (Rudnai, 1974) and Etosha Game Reserve 80:! (H. Berry, pers. comm.). This ratio for the Serengeti ecological unit was approximately 600:1 (Schaller, 1972) but here most of the prey animals are migratory. Prey group density, important for lion prey search success (Elliott, 1975), is high in the complex. The mean group sizes of wildebeest (Attwell, 1977) and zebra (P. M. Brooks, pets. comm.) are smaller than those recorded in East Africa and warthog and nyala each have a typical group size of less than six.

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Permanent water within the complex is well distributed as are the prey species. Unlike the situation which prevailed in the Kruger National Park prior to the artificial water-for-game programme (Smuts, 1976), water posed no limitation on areas where lion prides could establish residence. The physiognomy of the vegetation, with plentiful cover up to 1 m high, was ideal for the diurnal search for and stalking of prey (Elliott, 1975). Furthermore, the comparatively low numbers of leopard Panthera pardus and spotted hyaena Crocuta crocuta meant that there was little competition for the food resource. Movement from the complex took two forms. First, there was the dispersion of sub-adult males compelled to leave the pride and become nomads (Schaller, 1972) until able to secure tenure of a pride themselves; secondly, the incidental and temporary movement out by animals where their pride area boundary abutted the fence. Smuts et al. (1978b) found that the earliest age at which males had acquired tenure of a pride was five years. None of the males which left the complex had reached this age. This dispersion of sub-adult males is typical of the findings of other studies (Schaller, 1972; Bertram, 1973; Smuts, 1978b). The dispersal of sub-adult females was more gradual than that of males. Initially the movement of these animals from the area of introduction was to form new and adjacent prides. It was seven years after the sub-adult male dispersal from the complex commenced that the dispersal of sub-adult females occurred. Even then they were in the company of similar aged males. To achieve the management goal, it was reasoned that if the lion population was composed of animals which by virtue of their social status were not likely to leave the pride area, then much of the stock killing would be reduced. Those animals least likely to leave were the pride males, pride females and their cubs less than 18 months old. Accordingly in late 1974 a policy of culling sub-adult males at between 18 and 24 months old was adopted and initiated. Positive results of this management were immediately apparent (Fig. 3). The reduction in sub-adult male dispersion and consequent livestock losses continued through 1975 (Fig. 2) and it was possible to disband the predator control team. The improvements to the fence probably reduced the temporary movement from the area where the fence abutted a pride area boundary. Although a deterrent, dispersion was not, however, prevented but channelled through key points such as river crossings where 'lion proofing' is impossible. For two reasons, the reduction in livestock losses was not maintained during 1976. First, exceptionally heavy and late rains hampered the culling programme and some animals left the complex before they could be removed, and secondly, a large proportion of the stock losses was attributed to one lion. This animal's first recorded kills were over 120 km from the complex and it then moved into Swaziland. At this stage it was considered that the lion was not from the complex and therefore not the Natal Parks Board's responsibility. However, after some two months in Swaziland, it lost an eartag with which it had been fitted six months previously in Umfolozi. A prolonged and inept hunt was then terminated by staff from the reserve.

RE-ESTABLISHMENT AND MANAGEMENT OF A LION POPULATION IN ZULULAND

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When, in 1976, sub-adult females began to leave the complex, it was decided that culling would be extended to these as well but that only 50 ~o of the sub-adult females located would be removed. Subsequently in 1977 a n d 1978 the results of the management programme (Fig. 2) showed that its aim had largely been achieved. However, I do not believe that there are grounds for complacency. Artificial selection on the population may in the long term have some unknown and undesirable side-effects. In larger ecosystems where male nomads can live until they are able to win tenure of a pride, the normal tenure of a pride lasts about two to three years (Bertram, 1973). Under these circumstances the chances of father-daughter matings are reduced. With the severe reduction in the numbers of sub-adult males, male tenure in most prides in the complex has exceeded three years and in one instance has been as 100

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long as six years. Where sub-adult females have remained in these prides, inbreeding has probably occurred. To date no noticeable ill-effects have been noted in the cubs from these prides. It may well be that the selection pressures on large carnivores are so strict that animals with any undesirable traits do not reach maturity. Some selection has been applied in the culling of sub-adult males in that any animal showing physical development greater than his siblings is not removed. These and other sub-adult males which may have eluded culling have been sufficient to replace pride males in at least two prides within four years. There have also been two instances where a younger male has been able to gain acceptance into a pride already dominated by an adult male. It is appreciated that under the given circumstances management of the lion

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population will be an indefinite task. It is hoped that this will be accompanied by continued monitoring to ensure that a healthy and viable population is maintained.

ACKNOWLEDGEMENTS

I am grateful to those members of the complex staffwho assisted in the fieldwork or gave me information on lions in the area. In particular M. Astrup, H. Bentley, P. M. Brooks, C. J. Forrest, C. Freeman, J. van Rensburg and C. Wex. Dr G. L. Smuts and P. G o o d m a n made valuable comments on the manuscript which was typed by Miss E. A. Roy. The figures were prepared by Miss C. Pringle. This paper is published with the approval of the Natal Parks Game and Fish Preservation Board. REFERENCES ACOCKS, J. P. H. (1953). Veld types of South Africa. Mere., Bot. Surv. S. Afr., No. 28. Pretoria, Government Printer. ATTWELL, C. A. M. (1977). Reproduction and population ecology of the blue wildebeest Connochaetes t. taurinus in Zululand. PhD thesis, University of Natal. BERTRAM, B. C. R. (1973). Lion population regulation. E. Afr. WiMl. J., 11,215-25. BERTRAM, B. C. R. (1975). Social factors influencing reproduction in wild lions. J. Zool., Lond., 177, 463-82. BOURQU1N,O., V1NCENT,J. & H ITCH1NS, P. M. (1971). The vertebrates of the Hluhluwe Game Reserve-Corridor (State Land)--UmfoloziIGame Reserve Complex. Lammergeyer, 14, 5-119. COE, M. J., CUMMING,D. H. & PHILLIPSON,J. (1976). Biomass and production of large African herbivores in relation to rainfall and primary production. Oecologia (Berl.), 22, 341-54. ELLIOTT, J. P. (1975). Prey capture by the larger fissipeds." the AJ?ican lion. PhD thesis, University of British Columbia, Vancouver. GRIMSDELL,J. J. R. & BELL,R. H. V. (1972). Population growth of red lechwe Kobus leche lethe, Gray; in the Busanga Plain, Zambia. E. Afr. Wildl. J., 10, 11%22. GUOOSBERG, C. A. W. (1962). Simba, the life of the lion. London, Bailey Bros & Swinfen. HITCHINS, P. M. ( 1971). Results of game counts using a Bell47 G-4a Helicopter: Zululand Reserves." 1971. Pietermaritzburg, Natal Parks, Game and Fish Preservation Board. (Typed report.) HITCHINS, p. M. (1972). Results of game counts using a Bell47 G-4a Helicopter: Zululand Reserves. 1972. Pietermaritzburg, Natal Parks Game and Fish Preservation Board. (Typed report.) HITCHINS, P. M. (1973). Results of a game count using a Bell 47 G-4a Helicopter in the Hluhlflwe/Corridor/Umfolozi Complex 1973. Pietermaritzburg, Natal Parks Game and Fish Preservation Board. (Typed report.) MELTON, D. A. (1978). Ecology of waterbuck Kobus ellipsiprymnus ( Ogilby, 1833) in the UmJblozi Game Reserve. DSc thesis, University of Pretoria. PENNYCU1CK, C. J. & RUDNAI, J. (1970). A method of identifying individual lions, Panthera leo, with an analysis of the reliability of identification. J. Zool., Lond., 160, 497-508. RUDNAI, J. (1973). Reproductive biology of lions (Panthera leo massaica Neuman) in Nairobi National Park. E. Afr. Wildl. J., 11,241-53. RUDNA1, J. (1974). The pattern of lion predation in Nairobi Park. E. Aft. Wildl. J., 12, 213-25. SCHALLER, G. B. (1972). The Serengeti lion. Chicago & London, University of Chicago Press. SMUTS, G. L. (1976). Population characteristics and recent history of lions in two parts of the Kruger National Park. Koedoe, 19, 153-64. SMUTS, G. L. (1978a). Interrelations between predators, prey, and their environment. BioScience. 28, 316-20. SMUTS, G. L. (1978b). Effects of population reduction on the travels and reproduction of lions in Kruger National Park. Carnivore, !(2), 61-72.

RE-ESTABLISHMENT AND MANAGEMENT OF A LION POPULATION IN Z U L U L A N D

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SMUTS, G. L., WHYTE, 1. J. & DEARLOVE,T. W. (1977). A mass capture technique for lions. E. AJL WiMI.

J.,15,81 7. SMUTS, G. L., ANDERSON,J. L. & AUSTIN, J. C. (1978a). Age determination of the African lion (Panthera leo). J. Zool., Lond., 185, 115 46. SMUTS, G. L., HANKS, J. & WHVTE, I. J. (1978b). Reproduction and social organization of lions from the Kruger National Park. Carnivore, 1(1), 17-28. SMUTS, G. L., WnVTE, I. J. & DEARLOVE,T. W. (1978e). Advances in the mass capture of lions (Panthera leo). Proc. i'nt. Congr. Game Biologists, 13th, 42(~31. S1EELE, N. A. (1970). A preliminary report on the lions in the Umfolozi and Hluhluwe Game Reserves. Lammergeyer, 1 I, 68-79. VINCENT, J. (1970). Results of game counts: 1970. Pietermaritzburg, Natal Parks G a m e and Fish Preservation Board. (Typed report.)