Research Report Etosha National Park June 2015 a Study of The
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Research Report Etosha National Park June 2015 A study of the distribution and diversity of small mammal species within the different habitats of Etosha National Park (M. Hauptfleisch) Student Name: Matthew Walters Lecturer Name: M. Hauptfleisch Student Number: 213082969 Course of Study: Bachelor of Natural Resource Management Faculty: School of Natural Resources and Spatial Sciences Department: Agriculture and Natural Resource Management Table of Contents Introduction ............................................................................................................................................ 3 Aims and Objectives ................................................................................................................................ 3 Methods and Materials ........................................................................................................................... 4 Study Sites ........................................................................................................................................... 4 Dolomite Hills .................................................................................................................................. 5 Plains ............................................................................................................................................... 5 Okaukuejo ....................................................................................................................................... 5 Pan Edge .......................................................................................................................................... 5 Plain Steppes ................................................................................................................................... 5 Seasonal Water Depressions........................................................................................................... 5 Hillocks ............................................................................................................................................ 6 Terminalia Woodland ..................................................................................................................... 6 Methods .......................................................................................................................................... 6 Results ..................................................................................................................................................... 8 Overall Results .................................................................................................................................... 8 Trap success and abundance within each habitat .............................................................................. 9 Small mammal species richness within each of the habitats ........................................................... 10 Small Mammal Diversity ................................................................................................................... 11 Discussion.............................................................................................................................................. 12 Conclusions ........................................................................................................................................... 13 Recommendations ................................................................................................................................ 14 Acknowledgements ............................................................................................................................... 14 References ............................................................................................................................................ 15 2 Introduction Important to the concept of rangeland management within the African context is the appreciation and understanding of small mammal distribution and population size. Small mammals within this study ranged from the three orders Rodentia, Insectivora, and Macroscelidea. Rodentia, by far, makes up the largest percentage of mammal species, with an estimated percentage of 40% (Danell & Aave-Olsson, 2002, as cited in Sizuka, 2014). Globally Rodentia, characterised by their continuously growing chisel-like incisor teeth (Apps, 2000), has a total of 33 families, 481 genera and 2277 species (Carleton & Musser, 2005). The orders Insectivora (aimed at Shrews) and Macroselidae (aimed at Elephant Shrews), though less numerous than the Rodentia are also important indicators of food availability due to their insectivorous eating requirements. In terms of Insectivora, Shrews are placed in the family Soricidae, with its three sub-families, which along with three other families creates a total of 385 shrew species within 26 genera worldwide (Wilson & Reeder, 2011). Elephant shrews, found only in Africa, are made up of 19 species within 4 different genera (Schlitter, 2005). Since the study will be conducted in the Etosha National Park (ENP) in Namibia, a brief overview of small mammals in Namibia is required. Within the overall Namibian regional context, small mammal species of order Rodentia comprises of 35 species, Insectivora comprises of 4 species, and Macroscelidea comprises of 3 species (Matson & Blood, 1994). However, past research and knowledge into the distribution and composition of small species remains limited due to the ENP’s greater focus on the bigger game species (H. Berry, 2013). However, there have been two noteworthy previous studies within ENP that have for a large part given a better understanding of the small mammal composition within the ENP. The first study was conducted through the Etosha Ecological Institute, by M. Griffin, over two periods of his stay in Etosha, in which small mammals were trapped and identified from Kaross in the west to Namutoni in the east (Griffin, 1993). A second study related to the study of the diet of owl species within ENP, mostly in the Okaukuejo area (Dilley, 1996). This study was able to partly determine what small mammal species occurred in the area based primarily on what was found in the owl pellets. The study of small mammals is the key to understanding the dynamics of veld condition, based primarily on the small mammal species’ immediate position as primary and secondary consumers (Avenant, 2000; David & Jarvis, 1983; Foresman & Badyaev, 2005). All data acquired within the study period will be included in the Small Mammal Atlas of Namibia Project. Aims and Objectives Due to the lack of any current and updated small mammal species inventories within ENP, the aim of the project would be to contribute towards drawing up an inventory of all the small mammals that occur within the habitats of the Park. The research question posed and which the research project was meant to clarify is: what is the difference in species distribution and density within the various habitats of ENP? The null hypothesis (N0 Hypothesis) would be that there is no significant difference between the factors influencing diversity namely: species abundance and species richness observed between the various study sites. The alternative hypothesis (NA Hypothesis) is that there is a significant difference in abundance and species richness between the various study sites. As a means of achieving the overall aims, four objectives need to be realised: To determine the species distribution and diversity of small mammals within the Park. To determine the species richness of each sample site. 3 To determine the species diversity of the sample site according to individual species abundance and species richness. To compare the study sites and to determine the reasons as to why each of them would have been significantly different. Methods and Materials Study Sites Figure 1: Map of study sites at Okaukuejo Figure 2: Map of the study sites at Namutoni 4 Dolomite Hills As part of the February sampling period, a trapping site was placed on the mountain ranges 20 km south west of Okaukuejo on a road that led to a radio tower, that go by the name Ondundozonananandana (H. Berry, 1995). Overall, the geology is overwhelmingly dolomite typical of the Karst region with weakly developed shallow soils typical of arid regions (Barnard, 1998). Additionally, the vegetation is described as Mopane Savannah (Mannheimer & Curtis, 2009). The dominant tree species recorded were Colophospermum mopane, Sterculia africana, and several Commiphora species. The dominant grass species recorded were Aristida meridionales, Cenchrus ciliaris,and Enneapogon cenchroides. Trapping within this habitat zone took place 21-24 of February. Plains The open plains in which the study site is not a continuous open plain, rather it is open grassland plain surrounded by woodland. The sample site is situated near the road 9.3 km south west of Okaukuejo. Typical of the general Etosha area, the geology is mainly that of calcrete-limestone, and the soils are typically shallow (Barnard, 1998). The vegetation zone, same as that of the dolomite hills, is Mopane Savannah (Mannheimer & Curtis, 2009).The dominant tree species in and around the study site included: Colophospermum mopane, Catophractes alexandrii, and Acacia nebrownii. The dominant grass species within the study site included: Cenchrus ciliaris and Enneapogon cenchroides. Trapping within this habitat zone took place 22-25 of February. Okaukuejo The sample site at Okaukuejo was laid out in an area that was still within