Original article Nutrient dynamics and plant assemblages of Macrotermes falciger mounds in a savanna ecosystem Justice Muvengwi a, b, * , Hilton G.T. Ndagurwa c, d , Tatenda Nyenda b , Monicah Mbiba a, b a School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa b Department of Environmental Science, Bindura University of Science Education, Private Bag 1020, Bindura, Zimbabwe c Department of Forest Resources and Wildlife Management, Faculty of Applied Sciences, National University of Science & Technology, P.O. Box AC 939 Ascot, Bulawayo, Zimbabwe d Forest Ecology Laboratory, Faculty of Applied Sciences, National University of Science & Technology, P.O. Box AC 939 Ascot, Bulawayo, Zimbabwe article info Article history: Received 1 March 2016 Received in revised form 30 July 2016 Accepted 8 August 2016 Available online 13 August 2016 Keywords: Diversity Macrotermes falciger Mineralization Nitrogen Savanna Termite abstract Termites through mound construction and foraging activities contribute significantly to carbon and nutrient fluxes in nutrient-poor savannas. Despite this recognition, studies on the influence of termite mounds on carbon and nitrogen dynamics in sub-tropical savannas are limited. In this regard, we examined soil nutrient concentrations, organic carbon and nitrogen mineralization in incubation ex- periments in mounds of Macrotermes falciger and surrounding soils of sub-tropical savanna, northeast Zimbabwe. We also addressed whether termite mounds altered the plant community and if effects were similar across functional groups i.e. grasses, forbs or woody plants. Mound soils had significantly higher silt and clay content, pH and concentrations of calcium (Ca), magnesium (Mg), potassium (K), organic carbon (C), ammonium (NH 4 þ ) and nitrate (NO 3  ) than surrounding soils, with marginal differences in phosphorus (P) and sodium (Na) between mounds and matrix soils. Nutrient enrichment increased by a factor ranging from 1.5 for C, 4.9 for Mg up to 10.3 for Ca. Although C mineralization, nitrification and nitrification fraction were similar between mounds and matrix soils, nitrogen mineralization was elevated on mounds relative to surrounding matrix soils. As a result, termite mounds supported unique plant communities rich and abundant in woody species but less diverse in grasses and forbs than the surrounding savanna matrix in response to mound-induced shifts in soil parameters specifically increased clay content, drainage and water availability, nutrient status and base cation (mainly Ca, Mg and Na) concentration. In conclusion, by altering soil properties such as texture, moisture content and nutrient status, termite mounds can alter the structure and composition of sub-tropical savanna plant communities, and these results are consistent with findings in other savanna systems suggesting that increase in soil clay content, nutrient status and associated changes in the plant community assemblage may be a general property of mound building termites. © 2016 Elsevier Masson SAS. All rights reserved. 1. Introduction Epigeous termite mounds are a prominent feature in tropical and subtropical savannas. They are major sources of ecosystem spatial heterogeneity through their influence on soil physical and chemical properties such as topography, water status, decomposi- tion rates and nutrient cycling (Lee and Wood, 1971; Sileshi et al., 2010). Termites process and redistribute considerable quantities of organic material and soil particles during mound construction, and therefore strongly modify soil properties on mounds relative to the surrounding intermound matrix. These changes to soil prop- erties influence the composition, spatial distribution and dynamics of plants (Dangerfield et al., 1998; Joseph et al., 2012, 2013; Moe et al., 2009; Seymour et al., 2014), plant nutrient status (Grant and Scholes, 2006; Holdo and McDowell, 2004; Joseph et al., 2014) and animal landscape choices (Loveridge and Moe, 2004; Mobæk et al., 2005; Muvengwi et al., 2014). Thus, by modulating the availability of resources to other organism, termites act as ecosystem engineers in environments where they occur (Dangerfield et al., 1998; Jones et al., 1994). * Corresponding author. School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa. E-mail address: justicemuvengwi@yahoo.co.uk (J. Muvengwi). Contents lists available at ScienceDirect Acta Oecologica journal homepage: www.elsevier.com/locate/actoec http://dx.doi.org/10.1016/j.actao.2016.08.004 1146-609X/© 2016 Elsevier Masson SAS. All rights reserved. Acta Oecologica 76 (2016) 13e21