Ecological Impact of Large Herbivores at Artificial Waterpoints in Majete Wildlife Reserve, Malawi

Geenen, Kayla Adriana (2019-12)

Thesis (MScConsEcol)--Stellenbosch University, 2019.

Thesis

ENGLISH ABSTRACT: The management of water requires an important understanding of the impacts of supplementation on the ecosystem. In semi-arid environments worldwide, access to water is essential for the survival of wildlife and may affect the distribution of species within a reserve. Water supplementation, via artificial waterpoints (AWPs), has become common practice in maintaining wildlife densities when other water sources are limited in the dry season. Herbivores, especially those which are water-dependent, tend to congregate near water points and this congregation results in increased trampling and intense herbivore utilisation of the surrounding vegetation, eventually forming gradients of utilisation with increased utilisation pressure close to the AWP. Majete Wildlife Reserve (MWR) in southern Malawi has undergone a rehabilitation phase, which included a large wildlife reintroduction programme and as a necessity the construction of 10 AWPs. Concerns have now arisen as to the impact herbivores may be having on the vegetation surrounding these water points. In this study, vegetation change and structure surrounding AWPs and wildlife AWP usage was investigated. AWP utilisation by 12 species was studied with the use of camera traps from June 2017 to May 2018. African elephant (Loxodonta africana) and Cape buffalo (Syncerus caffer) were the most frequently observed species. AWPs were predominantly visited from 10:00 - 11:00, apart from black rhinoceros (Diceros bicornis minor) and Cape buffalo which preferred to utilise AWPs at dawn and dusk. Seventy-nine percent of AWP use observations were in the dry season, compared to 21% in the wet season. AWP utilisation was significantly higher in the south-eastern region of the reserve due to a lack of natural perennial water sources. Vegetation was sampled along three 2000m long transects in the N, SE and SW directions from six AWPs between July and November 2017 for woody vegetation, and between February and May 2018 for herbaceous vegetation. Both herbaceous vegetation condition and woody vegetation cover increased significantly with distance from water. Fixed-point photography was used to determine the change in vegetation cover between 2013 and 2018. Eight of the ten AWPs had an average decrease in vegetation cover. Woody vegetation cover surrounding AWPs decreased over the five-year period primarily due to elephant activity, and there was a coincided decrease in herbaceous vegetation cover. Soil erosion surrounding AWPs increased, due to an increase in water run-off and a decrease in soil stability when herbaceous vegetation cover decreased. AWPs are an important source of water for herbivores in the dry season in MWR, however the planning of AWP placement, maintenance and management options require careful consideration.

AFRIKAANSE OPSOMMING: Die bestuur van water vereis 'n goeie begrip van die gevolge van sodoende aanvulling op die ekosisteem. In semi-droë omgewings wêreldwyd is toegang tot water noodsaaklik vir die oorlewing van wilde diere en dit kan die verspreiding van spesies binne 'n reservaat beïnvloed. Wateraanvulling, deur kunsmatige waterpunte (AWPs), het gereelde praktyk geword in die handhawing van digtheid van wild in die natuur as ander waterbronne in die droë seisoen beperk is. Herbivore, veral waterafhanklike spesies, is geneig om naby waterpunte te vergader en hierdie gewoonte lei tot verhoogde vertrapping en oorbeweiding van die omliggende plantegroei, wat uiteindelik gradiënte van benutting vorm met 'n verhoogde gebruiksdruk naby die AWP. Majete Wildlife Reserve (MWR) in die suide van Malawi het 'n rehabilitasiefase ondergaan, wat 'n groot hervestigingsprogram vir wild insluit en word gesien as ‘n noodsaaklikheid vir die oprigting van 10 AWPs. Daar is nou kommer oor die impak wat herbivore op die plantegroei rondom hierdie waterpunte kan hê. In hierdie studie is plantegroeiverandering en -struktuur rondom AWPs en AWP-gebruik deur diere ondersoek. Die gebruik van die AWP deur twaalf spesies is bestudeer met behulp van ‘n kameratrap van Junie 2017 tot Mei 2018. Afrika-olifant (Loxodonta africana) en Kaapse buffels (Syncerus caffer) was die soorte wat die meeste voorkom. Afgesien van swartrenosters (Diceros bicornis minor) en Kaapse buffels, wat verkies om AWPs teen dagbreek en skemer te gebruik, is AWPs oorwegend van 10:00 - 11:00 besoek. Nege-en-sewentig persent van die AWP-waarnemings was in die droë seisoen, in vergelyking met 21% in die nat seisoen. AWP-benutting was aansienlik hoër in die suidoostelike gebied van die reservaat weens 'n gebrek aan natuurlike permanente waterbronne. Plantegroei opnames is onderneem op drie transekte van 2000 meter in die N-, SO- en SW-rigting vanaf ses AWPs tussen Julie en November 2017 vir houtagtige plantegroei, en tussen Februarie en Mei 2018 vir kruidagtige plantegroei. Bedekking van beide kruidagtige plantegroei en houtagtige plantegroei neem aansienlik toe met die afstand van water. Vastepuntfotografie was gebruik om die verandering in plantegroei tussen 2013 en 2018 te bepaal. Agt van die tien AWPs het 'n gemiddelde afname in plantbedekking gehad. Houtagtige plantegroei rondom AWPs het gedurende die vyfjaarperiode afgeneem, hoofsaaklik as gevolg van olifantaktiwiteit, en daar was 'n afname in die plantbedekking van plante. Wanneer die kruidagtige plantegroei bedekking laag was, het gronderosie rondom AWPs toegeneem, as gevolg van ‘n toename in die afloop van die water en 'n afname in grondstabiliteit. AWPs is 'n belangrike bron van water vir herbivore in die droë seisoen in MWR, maar die beplanning van AWP se plasing, instandhouding en bestuur moet noukeurig oorweeg word.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/107152
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