Ecology of plains zebra (Equus quagga) in Majete Wildlife Reserve, Malawi

De Vos, Charli (2017-12)

Thesis (MScConsEcol)--Stellenbosch University, 2017.

Thesis

ENGLISH ABSTRACT: Zebras occur throughout Africa and are responsible for sustaining the dynamics and overall well-being of the environments they reside in. However, zebras have experienced significant range reductions and restricted access to water and forage, as well as population declines within the last 100 years, contributing to the recent enlistment of plains zebra (Equus quagga) from Least Concern to Near Threatened on the IUCN Red List. In Majete Wildlife Reserve (MWR), located in southern Malawi, wildlife was almost completely extirpated from the reserve by 1985. In 2003 African Parks (Pty) Ltd. together with the Malawi’s Department of National Parks and Wildlife (DNPW) aimed to restore the reserve to its former glory. Fences were constructed, law-enforcement was improved and wildlife was reintroduced, including 174 plains zebra (hereafter referred to as zebra). More than ten years after the species’ initial reintroduction, zebra have successfully established within MWR. Prior to this study, no long-term monitoring was conducted on MWR’s zebra post reintroduction. In this study, zebra demographics, diet, waterhole usage and behaviour was investigated. The demography of zebra was determined with the use of an individual side-stripe database and an aerial survey. Of the estimated 571 zebra currently in the reserve, 243 were individually identified. Over the last few years, the population appears to have transitioned from the slower growth rate expected immediately after translocation to the rapid annual growth rate indicative of an approach toward carrying capacity. Adult zebra in the reserve currently exhibit a biased sex ratio of 1.0:0.8 (female:male). Population structure and organization is similar to established zebra populatons; however the formation of herds (multiple bands associating with each other) was never observed in MWR. In addition, stable isotope analysis was conducted to examine the seasonal diet of the species. Results confirmed that zebra are predominantly grazers that occasionally browse (trees, shrubs and forbs), even given the dominance of browse (dicotyledonous trees and shrubs) in the miombo woodland environment of Majete. The proportion of browse consumed, however, varied significantly among the seasons, with only 1.5% browse consumed during the late wet season compared to 10.2% in the late dry season. Artificial waterhole usage by zebra was studied with the use of camera traps. Waterholes were predominantly visited at 09:00, 13:00 and 14:00. However, when natural surface water decreased and more animals aggregated around artificial waterholes, it appeared that zebra shifted their visitation time to avoid interspecific competition around these waterholes. Finally, the diurnal time budgets of this species indicated that family bands allocate 41.8% of their time to feeding behaviour, followed by resting (18.5%), locomotion (10.9%), vigilance (7.5%), maintenance (2.7%) and social behaviour (1.4%). In comparison, bachelor bands allocated 27.0% to vigilance behaviour, followed by locomotion (21.0%), feeding (18.4%), resting (15.4%), maintenance (6.4%) and social behaviour (2.4%). It is unknown if the relatively small amount of time spent feeding was compensated for nocturnally or is indicative of low graze availability during the dry season. Based on the findings of this study, issues facing the conservation of zebra within MWR were identified and conservation and management options are presented.

AFRIKAANSE OPSOMMING: Sebras kom regdeur Afrika voor en is verantwoordlik om die dinamika en welstand van die ekosisteem waarin hulle voorkom te onderhou. Binne die laaste 100 jaar, is hulle egter beïnvloed deur habitat verlies, beperkde toegang tot water en kos, sowel as ‘n afname in populasiegetalle. Hierdie het bygedra tot die onlangse verandering in die vlaktesebra (Equus quagga) se IUCN Rooi Lys klassifikasie vanaf Lae Risiko na Byna Bedreig. Die Majete Wildreservaat (MWR), wat in die suide van Malawi geleë is, was amper gestroop van alle wild teen 1985. In 2003 het African Parks (Pty) Ltd. saam met Malawi se Departement van Nationale Parke en Wild (DNPW) beoog om die reservaat te herleef. Heinings is opgerig, wetstoepassing is versterk en wild is gehervestig, insluitend 174 vlaktesebras (hierna slegs verwys as sebra). Nou, meer as tien jaar na die aanvanklike herlewing, is sebra suksesvol gevestig in die reservaat, maar geen lang-termyn navorsing is al gedoen op die reservaat se sebra na die herinstelling nie. In hierdie studie, is die demografie, dieet, watergatgebruik en gedrag van die sebra ondersoek. Die demografie van die sebra is bepaal met behulp van ‘n individuele kant-streep databasis en ‘n lugopname. In totaal is 243 individue geidentifiseer van ‘n beraamde 571. Dit wil voorkom dat die populasie in die laaste paar jaar, vanaf ‘n stadiger bevolkingsgroeikoers, soos wat verwag word tydens die eerste paar jaar na hervestiging van wild, bevorder het na ‘n vinnige bevolkingsgroeikoers wat aandui dat die populasie die dra-kapasiteit benader. Volwasse sebra in die reservaat vertoon ‘n bevooroordeelde geslagsverhouding van 1.0:0.8 (vroulik:manlik). Daar is gevind dat die demografie soortgelyk is aan ander gevestigde populasies, alhoewel troppe (die samekoms van groepe) nooit waargeneem is in MWR nie. Verder is die dieet van sebra ondersoek deur gebruik te maak van stabiele isotoop analise van mismonsters. Resultate het bevestig dat sebra hoofsaaklik gras vreet en slegs af en toe blare sal eet, ongeag daarvan dat takvoer (tweesaadlobbige bome and bosse) meer algemeen bekombaar is in die miombo bos habitat van Majete. ‘n Duidelike seisoenale verskil in die persentasie blare wat gevreet is, is ook gevind. In die lae nat seisoen het hulle dieet slegs 1.5% takvoer bevat in vergelyking met 10.2% tydens die lae droë seisoen. Die besoek aan kunsmatige watergate is ondersoek deur gebruik te maak van kamerastrikke. Kunsmatige watergate was hoofsaaklik besoek tydens 09:00, 13:00 en 14:00. Wanneer natuurlike waterbronne egter begin opdroog het en meer diere rondom die kunsmatige watergate begin saamdrom het, wil dit voorkom asof sebra hulle besoektye aan kunsmatige watergate verander het om interspesifieke kompetisie te vermy. Laastens, het die daglig tydsbegrotings van die spesie vasgestel dat familie groepe 41.8% van hulle tyd spandeer om te vreet, daarna om te rus (18.5%), te beweeg (10.9%), waaksaam te wees (7.5%), hulself te versorg (2.7%) en om sosiaal te verkeer (1.4%). Rondloper mannetjies spandeer weer die meerderheid van hulle tyd om waaksaam te wees (27.0%), gevolg deur te beweeg (21.0%), te vreet (18.4%), te rus (15.4%) en sosiaal te verkeer (2.4%). Dit is onbepaald of die relatiewe klein hoevelheid tyd wat deur die dag aan vreet spandeer was, gekompenseer word deur meer tydens die aand te vreet en of dit ‘n gevolg is van die skaarsheid van gras tydens die droë seisoen. Die bevindings van hierdie studie is gebruik om kwessies rakende die bewaring van sebra in MWR te identifiseer en ‘n bewarings- en bestuursplan voor te stel.

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