Habitat use and diet selection of reintroduced white rhinoceros (Ceratotherium simum) in Pafuri, Kruger National Park

Pedersen, Gayle (2009-03)

Thesis (MSc (Conservation Ecology and Entomology))--Stellenbosch University, 2009.

Thesis

ENGLISH ABSTRACT: In 2005, six white rhinoceros (Ceratotherium simum) were reintroduced into Pafuri, in the far northern section of Kruger National Park (KNP), South Africa, as part of a large mammal reintroduction project. All six individuals were fitted with horn radio transmitters. Rhinos have been absent from Pafuri for over a century, and this project aimed to establish a breeding nucleus in the area. The aim of this study was to monitor post-release movement and habitat use of these animals within the 203 km2 study area and assess the short term success of the re-introduction project as well as the suitability of the five landscape types in Pafuri as a habitat for white rhinoceros. Habitat suitability and selection was assessed at two ecological hierarchical scales: 1) landscape system, analysed further down to the spatial scale of range and territory establishment, and 2) feeding station for diet selection. Rhinos were tracked for 12 months and a database of 719 sighting records was compiled. These data were used to determine the utilisation of and preference between the Pafuri landscape types, using preference indices that compare utilisation versus availability. An a-LoCoH nonparametric kernel method was used to calculate home ranges and utilisation distributions of each rhino. Feeding surveys were attempted by backtracking along fresh rhino feeding paths and recording the grass species present and eaten in 0.7 m x 0.7 m quadrats. Faecal samples were collected and analysed using microhistological techniques and dietary composition was assessed for each rhino. Landscape preference analyses showed that the rhinos favoured Colophospermum mopane Shrubveld on calcrete in the dry season, and the Punda Maria Sandveld in the wet season. The territory establishment of the dominant bull was substantially larger (44.8 km²) than those of adult male rhinos in the rest of KNP. Ranging areas of the mature females (17 – 25.4 km²), were consistent with sizes of previous studies. The two sub-adults ranged far more extensively, establishing an 84.1 km² annual range during the study period. The annual diet consisted of mostly perennial grass species, with moderate grazing value species dominating for most of the year. Dietary analyses showed that Schmidtia pappophoroides, Eragrostis superba, Enneapogon cenchroides, Cenchrus ciliaris and Stipagrostis uniplumis were the primary grass species consumed. vii This study demonstrated that the Pafuri rhinos are behaving similarly to rhinos established in other areas, with movements around the landscapes being primarily influenced by rainfall and permanent water sources, and the high quality grazing that is more abundant in the wet season. Their range and territory sizes were inevitably large, for a low density area, but not uncommonly so. The most significant outcome of this study was the preference shown for the Colophospermum mopane Shrubveld on calcrete landscape that is classed as unique within South Africa, and was also ranked as ‘avoided’ by the earlier KNP studies into landscape preferences of rhinos. The grass cover in Pafuri, although sparse and very dry, contained a diversity of low to high grazing value grasses that the rhinos appeared to exploit to the best of their ability. The abundance of moderate grazing value species in their diets, and the low number of low grazing value species suggests that they are maximising the opportunities to graze on nutritious grasses when they are available. Our findings suggest that the Pafuri area is suitable for the establishment of a small breeding nucleus of white rhinos. The abundance of permanent water, in the form of springs, is a great advantage however, the potential for bush encroachment into grasslands in areas of such low rainfall needs to be considered if the population continues to grow at the current rate. The birth of two new calves in 2008 confirms that these rhinos have settled and adapted to their new habitat, and is a very promising sign for the future of this increasing subpopulation.

AFRIKAANSE OPSOMMING: In 2005 is ses wit renosters (Ceratotherium simum) hervestig in Pafuri in die noordelike gedeelte van die Kruger Nasionale Park (KNP), Suid-Afrika, as deel van ‘n groot soogdier hervestigings projek. Al ses individue is gemerk met horing radioseintoestelle. Renosters kom vir al meer as ‘n honderd jaar nie meer in Pafuri voor nie en hierdie projek was daarop gemik om ‘n teel-nukleus in hierdie gesied te vestig. Die doel van hierdie studie was om die verspreiding van die renosters na loslating en habitat-gebruik binne die 203 km2 studie-omgewing te monitor, om die korttermyn sukses van die hervestigings program te evalueer en ook te kyk na die gepastheid van die vyf landskap-tipes in Pafuri as ‘n geskikte habitat vir die wit renosters. Habitatgepastheid en seleksie is geëvalueer volgens twee ekologiese hiërargiese skale: 1) landskapsisteem, wat in meer resolusie tot die ruimtelike skaal van reikwydte en omgewingsvestiging geanaliseer is, en 2) voedings-stasie vir dieet-seleksie. Renosters is vir 12 maande gevolg en ‘n databasis wat 719 waarneming-rekords bevat, is opgestel. Laasgenoemde data is gebruik om die gebruik en voorkeur vir die Pafuri landskap tipes te bepaal met behulp van voorkeur-indikators wat die gebruik met beskikbaarheid vergelyk het. ‘n a-LoCoH nie-parametriese kern metode is gebruik om die reikwydte en gebruiksverspreidings van elke renoster te bereken. Voedingsopnames is gedoen deurdat vars renoster voedings-paadjies terugwaarts gevolg is en die grasspesies teenwoordig en waarop gevoed is, in 0.7 m x 0.7 m kwadrante te bepaal. Mismonsters is versamel en geanaliseer deur gebruik te maak van mikro-histologiese tegnieke en voedingswaarde-samestellings is vasgestel vir elke renoster . Landskapsvoorkeur analises dui daarop dat die renosters in die droë seisoen Colophospermum mopane struikveld wat op kalkreet groei verkies en die Punda Maria Sandveld in die reën seisoen. Die terrein vestiging van die dominanate bul was aansienlik groter (44.8 km²) in vergelyking met die volwasse bul renosters in die res van die KNP. Reikwydte van die volwasse koeie (17 – 25.4 km²) was ooreenstemmend met dié van vorige studies. Die reikwydte van die twee subvolwassenes het baie meer gevarieer, deurdat ‘n 84.1 km² jaarlikse reikwydte gedek was binne die studie periode. Die jaarlikse dieet het meestal bestaan uit meerjarige ix grasspesies, met spesies met matige weidingswaarde wat oorheers vir meeste van die jaar. Voedingswaarde analises dui daarop dat Schmidtia pappophoroides, Eragrostis superba, Enneapogon cenchroides, Cenchrus ciliaris en Stipagrostis uniplumis die primêre gras spesies was waarop gewei word. Die studie het bewys dat die Pafuri renosters soortgelyke gedragspatrone vertoon het as renosters in ander gevestigde gebiede, deurdat bewegings binne die landskap hoofsaaklik beïnvloed word deur reënval en permanente waterbronne, asook die hoë gehalte weidingsbronne beskikbaar gedurende die reën seisoen. Hulle reikwydte- en terrein-groottes was uiteraardelik groot vir ‘n lae-digtheid areas, maar dit is nie buitengewoon nie. Die mees betekenisvolle gevolgtrekking van die studie was die voorkeur vir die Colophospermum mopane struikveld op kalkreet landskappe wat beskou word as uniek aan Suid-Afrika, en wat ook beskou was as ‘vermy’ deur vroër KNP studies tov. landskap voorkeure spesifiek vir renosters. Die grasbedekking in Pafuri, alhoewel yl en baie droog, het tog oor ‘n verskeidenheid grasse beskik wat van lae tot hoë weidings waarde het, en wat die renosters tot die beste van hulle vermoë benut het. Die oorvloedige teenwoordigheid van beide spesies met matige weidingswaarde in hulle dieët en die lae hoeveelheid van spesies met lae weidingswaarde, impliseer dat hulle die geleentheid om op voedingsryke grasse te voed ten volle benut wanneer dit beskikbaar is. Ons resultate dui daarop dat die Pafuri omgewing geskik is vir die vestiging van ‘n klein teel-nukleus van wit renosters. Die oorvloedige teenwoordigheid van permanente waterbronne in die vorm van fonteine is ‘n groot voordeel, maar die kans vir bosindringing in hierdie grasveld-gebiede met lae reënval moet oorweeg word sou die populasie aanhou toeneem teen die huidige tempo. Die geboorte van twee nuwe kalfies in 2008 staaf die moontlikheid dat die renosters gevestig en aangepas het in hulle nuwe habitat, wat ‘n baie belowende teken is vir die toekoms van die groeiende subpopulasie.

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