Journal of Tropical Ecology http://journals.cambridge.org/TRO Additional services for Journal of Tropical Ecology: Email alerts: Click here Subscriptions: Click here Commercial reprints: Click here Terms of use : Click here Termitaria as preferred browsing patches for black rhinoceros (Diceros bicornis) in Chipinge Safari Area, Zimbabwe Justice Muvengwi, Hilton G. T. Ndagurwa, Tatenda Nyenda and Innocent Mlambo Journal of Tropical Ecology / Volume 30 / Issue 06 / November 2014, pp 591 - 598 DOI: 10.1017/S0266467414000480, Published online: 04 September 2014 Link to this article: http://journals.cambridge.org/abstract_S0266467414000480 How to cite this article: Justice Muvengwi, Hilton G. T. Ndagurwa, Tatenda Nyenda and Innocent Mlambo (2014). Termitaria as preferred browsing patches for black rhinoceros (Diceros bicornis) in Chipinge Safari Area, Zimbabwe. Journal of Tropical Ecology, 30, pp 591-598 doi:10.1017/S0266467414000480 Request Permissions : Click here Downloaded from http://journals.cambridge.org/TRO, IP address: 137.132.123.69 on 23 Oct 2014 Journal of Tropical Ecology (2014) 30:591–598. © Cambridge University Press 2014 doi:10.1017/S0266467414000480 Termitaria as preferred browsing patches for black rhinoceros (Diceros bicornis) in Chipinge Safari Area, Zimbabwe Justice Muvengwi∗,†,1, Hilton G. T. Ndagurwa‡,§, Tatenda Nyenda† and Innocent Mlambo† ∗ School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg Wits 2050, South Africa † Department of Environmental Science, Bindura University of Science Education, Private Bag, 1020, Bindura, Zimbabwe ‡ Forest Ecology Laboratory, Faculty of Applied Science, National University of Science & Technology, P.O. Box AC 939 Ascot, Bulawayo, Zimbabwe § Department of Forest Resources & Wildlife Management, Faculty of Applied Science, National University of Science & Technology, P.O. Box AC 939 Ascot, Bulawayo, Zimbabwe (Received 2 April 2014; revised 9 August 2014; accepted 10 August 2014; first published online 4 September 2014) Abstract: This study tested the hypothesis that the black rhinoceros browses more on termitaria than off termitaria vegetation due to elevated soil and foliar nutrient levels on termitaria. We investigated the role of termitaria in providing nutrient-rich forage for the black rhinoceros, by comparing the preference (selection ratio) for vegetation occurring on and off termitaria, and then testing its relationship with foliar nutrient concentrations. Soil nutrients, bite intensity, tree species diversity, vegetation density, canopy cover and basal area were also surveyed on and off termitaria. We sampled 25 termite mounds together with their corresponding control plots in Chipinge Safari Area, Zimbabwe. Soil and foliar N, P, K, Ca and Na concentrations were greater on termitaria than off termitaria, with approximately twice the concentration of these nutrients. Browse preference followed the between-site differences in soil and foliar nutrient concentrations, with higher selection ratios and bite intensities for vegetation on termitaria than off termitaria. Diospyros quiloensis was the most preferred browse species whilst Combretum imberbe, Kigelia africana and Strychnos innocua were the least. In conclusion, the black rhino preferred vegetation on termitaria to that in the surrounding matrix, and utilization of vegetation can be influenced by the soil substrate on which tree species grow. Key Words: Diceros bicornis, preference, savanna, termitaria, vegetation, Zimbabwe INTRODUCTION from the mound. However, the underlying causes for differences in browse preference were not tested. This Termites, through mound construction and soil particle limits our understanding of the factors driving the positive redistribution, act as ecosystem engineers, altering selection for vegetation on termitaria by the black rhino soil physical properties, nutrient availability, hydrology in the savanna. and topography which can ultimately influence local The relatively nutrient-rich soils of termitaria reduce plant richness, plant spatial distribution and vegetation competition for limiting nutrients i.e. nitrogen (N) and dynamics (Dangerfield et al. 1998, Fleming & Loveridge phosphorus (P), which alters the competitive dominance 2003, Grant & Scholes 2006, Holdo & McDowell 2004, of plants and may also enable the coexistence of nutrient- Joseph et al. 2012, 2013;Moeet al. 2009,Seymour demanding plants. As a result, there is an increase in plant et al. 2014). These changes have potential to influence productivity and species richness on termitaria compared browse selection by mammalian herbivores in savanna with the matrix (Fleming & Loveridge 2003, Joseph et al. woodlands where termite mounds are an important 2012,Moeet al. 2009,Seymouret al. 2014, Sileshi et al. feature of the landscape. For example, in the miombo 2010). This potentially increases the quantity and variety woodlands of central Zimbabwe, Loveridge & Moe (2004) of browse available for browsers, and at the same time found that the black rhino browsed more on vegetation reduces intraspecific competition between the animals. on termitaria than at distances from termitaria. In this Woody plants on termitaria have also been found to have study, however, preference was tested by comparing the higher leaf N, P and palatability than those in the matrix cumulative browse scores on different trees with distance (Grant & Scholes 2006, Holdo & McDowell 2004, Joseph et al. 2014). Additionally, termitaria act as fire refugia for woody plants which allow woody species to persist 1 Corresponding author. Email: [email protected]. on mounds post fire (Joseph et al. 2013). Further, the 592 JUSTICE MUVENGWI ET AL. soil moisture content is relatively higher on termitaria The mammalian fauna is represented by the than the surrounding matrix (Dangerfield 1991), which black rhinoceros Diceros bicornis (Linnaeus, 1758), maintains evergreen woody species on mounds. It is, kudu Tragelaphus strepsiceros (Pallas, 1766), buffalo therefore, expected that animals are likely to favour Syncerus caffer (Sparrman, 1779), warthog Phacochoerus vegetation on termitaria over that in the matrix. aethiopicus (Pallas, 1766), bushbuck Tragelaphus scriptus Our study site in south-eastern Zimbabwe, Chipinge (Pallas, 1766), grysbok Rhacerus melanotis (Thunberg, Safari Area, is home to a black rhino population 1811), impala Aepyceros melampus (Lichtenstein, 1812) translocated in 1990 from the Zambezi Valley secondary and bush pig Potamochoerus larvatus (F. Cuvier, 1822). to intensive poaching (Rachlow & Berger 1998). The carnivores present in the study area include leopard Macrotermes termitaria characterize much of the savanna Panthera pardus (Linnaeus 1758), spotted hyena Crocuta vegetation on soils relatively poor in nitrogen (N), crocuta (Erxleben, 1777) and black-backed jackal Canis extractable phosphorus (P) and total exchangeable mesomelas (Schreber, 1775). cations (Bloesch 2008, Brossard et al. 2007). Thus, if browse from termitaria has greater nutritional value than that found in the matrix, the possible significance of METHODS mounds as sources of nutrient-enriched forage for the black rhino is likely to be considerable. Plot measurements In this study, we tested the hypothesis that the black rhino would browse more on vegetation located on We surveyed vegetation on and off termite mounds termite mounds than that in the surrounding matrix in December 2013. The study area was divided into (hereafter referred to as on termitaria and off termitaria, 10 blocks of c.26km2 in area. Five blocks were randomly respectively) in Chipinge Safari Area, south-eastern chosen for surveying. In each block, a belt transect (30 m Zimbabwe. We expected that the preference for vegetation wide; 5 km long) was constructed from the southern side on termitaria would be driven by the foliar nutrient running through the centre of the grid in a northerly status of the browse since browse preference by animals direction. At each 1 km along each transect, excluding the has been shown to be related to the nutritional quality starting point, a termite mound was selected for survey of the browse (Cooper & Owen-Smith 1985, Cooper in the randomly chosen perpendicular to the transect. et al. 1988). Additionally, by determining preference for Five termite mounds were surveyed from each of the species occurring both on termitaria and off termitaria, five transects for a total of 25 sites. Termitaria with we aimed to identify key browse species favoured by the surface area at least 100 m2 and height ࣙ 1mwere black rhino in this system. selected as they contained a variety of plant assemblages (Joseph et al. 2012). The long and short diameter of each termite mound was measured at right angles using a tape STUDY SITE measure. The mean (±SE) termite mound height was 2.56 ± 0.5 m and average mound surface area was 334 The study was conducted in Chipinge Safari Area ± 0.7 m2. For each termite mound, a circular control plot 2 (20°21 S, 32°43 E) covering 261 km in south-eastern was placed at least 30 m away from the centre of the target Zimbabwe. The area is relatively dry, and receives termite mound or from the centre of any other nearest −1 an average rainfall of 489 mm y (Department of mound in the area. The bearing of the control plot from Meteorological Services unpubl. data). The mean daily the target mound was taken as the first value between temperature recorded over the last 20 y is 23.3 °C, zero and 360 generated from a scientific calculator.