Ecology of Three Apex Predators in Majete Wildlife Reserve, Malawi
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Ecology of three apex predators in Majete Wildlife Reserve, Malawi By Willem Daniel Briers-Louw Thesis presented in partial fulfilment of the requirements for the Degree of Master of Science, Department of Conservation Ecology & Entomology, Stellenbosch University Supervisor: Dr Alison J. Leslie Faculty of AgriSciences Department of Conservation Ecology & Entomology December 2017 Stellenbosch University https://scholar.sun.ac.za Declaration By submitting this thesis electronically, I declare that the entirety of the work contained therein is my own, original work, that I am the sole author thereof (save to the extent explicitly otherwise stated), that reproduction and publication thereof by Stellenbosch University will not infringe any third party rights and that I have not previously in its entirety or in part submitted it for obtaining any qualification. Willem Daniel Briers-Louw December 2017 Copyright © 2017 Stellenbosch University All rights reserved i Stellenbosch University https://scholar.sun.ac.za Abstract Apex carnivores play an important role in the ecosystem by regulating prey via predation. Anthropogenic influences have resulted in rapid range and population reductions of large carnivores across the African continent. These carnivores are often reintroduced into protected areas to compensate for human-induced losses, restore ecosystem functioning and promote eco-tourism. Majete Wildlife Reserve in Malawi is a prime example, as human persecution resulted in the extirpation of large carnivores, with the exception of a small spotted hyena (Crocuta crocuta; hereafter hyena) population. As from 2003, African Parks attempted to rectify this problem by restoring and developing the reserve. Between 2011 and 2012, three lions (Panthera leo) and six leopards (Panthera pardus) were reintroduced. The aim of this study was to describe the ecology of the apex predators and to determine whether the felid reintroduction was successful or not. Lion and leopard movements and home ranges were determined using GPS collars. The reintroduction of felids was considered successful. This was based on: (1) reduced post-release movements; (2) lack of homing tendencies; (3) breeding success; and (4) population persistence. Mean home ranges of lion (380.45 ± 117.70 km2 [SE]) and leopard (495.08 ± 80.99 km2), were the largest on record for any reintroduced felid in Africa, which was likely due to a low competitor density. Thus, we expect home range sizes to decrease with an increase in conspecific density. Population abundances and densities were estimated with the use of camera traps. The known lion population increased to eleven individuals in five years, while the leopard population was estimated at 11 (range = 9–17). This indicates population persistence and growth. Both founder populations were small and require additional translocations to maintain genetic diversity. Hyena density (2.62 hyenas/100 km2) and clan size (5.33 ± 0.67) were the lowest estimates in any woodland habitat and comparable to arid areas. This may be explained by decades of direct persecution and poaching of their prey, or a naturally low density. Predator diets were described and compared by means of scat analysis. Lion and hyena exhibited a high dietary overlap of medium to large herbivores. Using Jacobs’ preference index, both species preferred warthog (Phacocoerus africanus) and waterbuck (Kobus ellipsiprymnus). Hyenas selected a broader range of prey, likely reducing competition with lions (which almost exclusively selected only four species). In contrast, leopards occupied a lower dietary niche, which consisted mainly of small-to medium-sized ungulates. These findings indicate that the three apex predators use resource partitioning to reduce competition. ii Stellenbosch University https://scholar.sun.ac.za This study suggests that reintroduction is a viable tool for re-populating large carnivores in protected areas in Malawi. The current predator population appeared to have a minimal impact on prey populations due to their small population size. We recommend long-term monitoring of predator- prey dynamics as the predator populations increase to prevent major ecological imbalances. Finally, we encourage management to focus energy and resources on the formation of a managed carnivore metapopulation to establish a genetically viable carnivore population within Malawi. iii Stellenbosch University https://scholar.sun.ac.za Opsomming Top roofdiere speel ‘n belangrike rol in die regulering van ekosisteme deur predasie. Menslike invloede het gelei tot ‘n vinnige afname in karnivoor populasiegetalle en habitatverliese in Afrika. Hierdie karnivore word dikwels hervestig in bewaarde areas om te kompenseer vir menslik ge- induseerde verliese, funksionering van ekosisteme te herstel en eko-tourisme te bevorder. Majete Wildreservaat is ‘n prima voorbeeld waar menslike vervolging groot karnivore uitgeroei het, behalwe vir die gevlekte hiëna (Crocuta crocuta; hierna hiëna) populasie. Vanaf 2003 het African Parks gepoog om hierdie probleem reg te stel deur restourasie en ontwikkeling van die reservaat. Tussen 2011 en 2012 was drie leeus (Panthera leo) en ses luiperds (Panthera pardus) hervestig. Die doel van hierdie studie was om die ekologie van die top roofdiere te beskryf en te bepaal of die hervestiging van leeus en luiperds suksesvol was. Bewegings en gebiede van leeus en luiperds is bepaal met hulp van GPS-halsbande. Die hervestiging van hierdie spesies was beskou as suksesvol. Na vrystelling was daar: (1) ‘n afname in beweging; (2) geen behoefte om huiswaarts (herkoms) te keer nie; (3) sukses met teling; en (4) populasie oorlewing. Die gemiddelde gebied van leeus (380.45 ± 117.70 km2)[SE]) en luiperds (495.08 ± 80.99 km2) was die grootste op rekord vir enige hervestigde karnivoor in Afrika, moontlik as gevolg van lae kompetisie digtheid. Dus verwag ons ‘n verkleining van gebiede namate die kompetisie digtheid toeneem. Populasiegetalle- en digthede is geskat met behulp van kamerastrikke. In vyf jaar het die erkende leeu populasie tot elf individue vermeerder, terwyl die luiperd populasie op 11 (omvang = 9–17) staan, wat populasie oorlewing en groei aandui. Beide stigter populasies was klein, daarom is addisionele translokasie nodig om genetiese diversiteit te behou. Hiëna digtheid (2.62 hiënas/100 km2) en stamgroep grootte (5.33 ± 0.67) was die kleinste in soortgelyke habitat. Hierdie is moontlik as gevolg van direkte vervolging en stroping van hulle prooi oor dekades of ‘n natuurlike lae digtheid. Roofdierdiëte is beskryf en vergelyk deur misanalise. Leeus en hiënas se diëte van medium tot groot prooi het tot ‘n groot mate oorvleuel. Gebaseer op Jacobs’ indeks, het beide spesies vlakvark (Phacocoerus africanus) en waterbok (Kobus ellipsiprymnus) verkies. Hiënas het egter ‘n wye verskeidenheid prooi geëet, moontlik weens mededinging met leeus (wat amper uitsluitlik net vier spesies geëet het). In kontras met leeus en hiënas, het luiperds ‘n kenmerkende dieet, wat hoofsaaklik uit klein tot medium grootte prooi bestaan. Hierdie resultate bewys dat die drie karnivore kompetitise met mekaar verminder deur verskillende diëte te volg. Hierdie studie dui daarop dat hervestiging van groot karnivore in bewaarde areas in Malawi ‘n vatbare tegniek is. Tot dusver het die roofdierpopulasie ‘n klein impak op die prooipopulasies gehad weens iv Stellenbosch University https://scholar.sun.ac.za die klein roofdier populasiegetalle. Ons beveel aan dat roofdier-prooi dinamika gemonitor word soos wat die roofdiere toeneem om ekologiese wanbalanse te vermy. Ten slotte, moedig ons die bestuur van African Parks aan om ‘n karnivoor meta-populasie in Malawi te stig, wat ‘n genetiese vatbare populasie kan volhou binne die landsgrense. v Stellenbosch University https://scholar.sun.ac.za Acknowledgements Thank you to African Parks (Majete) Pty Ltd. for allowing me to witness and be part of the amazing success story that is Majete Wildlife Reserve. Thank you to everyone who made this study possible, particularly those who were involved in the reintroduction and collaring of the lions and leopards. Thank you to Majete management and the entire game capture team, for allowing me to be part of the lion re-collaring, this was truly a once-in-a-lifetime experience. Next, I would like to thank Craig Hay and Gervaz Tamala for their supervision and willingness to assist me with my research. To the rest of the management team, thank you for making me feel part of the Majete family. Thank you to the law enforcement team, especially Tizola Moyo, Martin Awazi and John Jiya for organising scouts, providing valuable information and allowing access to reports. To all the scouts who assisted me in the field I am greatly appreciative. Your knowledge about Majete really aided my project and helped me learn so much about the bush. I would also like to thank all the stores-men and mechanics at the workshop, particularly Africa’s best bush-mechanic, Isaac Mlilo, who kept our vehicles going despite numerous setbacks and was always there when we needed him. Thank you to Dr Alison Leslie who provided me the opportunity to experience the “warmest” heart of Africa. Majete has become my home and I will never forget the stories and friends that have been made along this incredible journey. I am overjoyed to have been part of this amazing team and to have experienced this with you. I would like to thank all the Earthwatch volunteers for their contribution. Thank you to Prof Arthur Rodgers for your correspondence and help with operating Home Range Tools in ArcGIS. Thank you to Dr Matt Hayward for providing equations for predator carrying capacities and Prof Martin Kidd for help with statistics. I would also like to thank Dr Dan Parker and Rhodes University for providing access to their reference of animal hair cross-sections. A special thanks to Prof Antoinette Malan for her generosity with laboratory equipment which proved invaluable for the scat analysis. Thank you to the Hay family for your support throughout my stay in Majete and being my role-models. To all my fellow researchers, Anel Olivier, Claire Gordon, Frances Forrer and Kayla Geenen, thank you for all your help and for the good times we shared in Majete.