The effects of fire and elephants on species composition and structure of the Niassa Reserve, northern Mozambique

In the Miombo Woodlands Region of south-central Africa, the interaction between fires and elephants is one of the main drivers of vegetation, along with climate, soils and topography. Fire-elephant interaction is particularly important in conservation areas where elephant populations are confined and anthropogenic fires occur every year. The effects of this interaction on vegetation composition and structure have not been extensively studied in the region. The Miombo woodlands of the 42,000 km2 Niassa Reserve in northern Mozambique are subject to annual anthropogenic fires and an increasing elephant population, but it is not understood whether, the elephant-fire interaction is manifest. We investigate the distribution of plant species composition and ecosystem structure, and their relationships with environmental and disturbance factors within the Niassa Reserve. Fifty sampling plots were established and measurements for vegetation composition and structure, fire and elephant damage to plants, environmental (edaphic and topographic) and disturbance data were collected. We used multivariate statistics analysis including detrended correspondence analysis (DCA), canonical correspondence analysis (CCA) and Principal Component Analysis (PCA) to explore the data. Three groups of species were distinguished according to their abundances: the Miombo group, the eastern Combretacea group and the western Uapaca group. The miombo group was uniformly distributed in the area and independent of environmental and disturbances factors. The Uapaca group followed an elevation gradient from east to west, while the combretacea group was explained by edaphic and disturbance factors. The damage to the woody component was predominant in the east. The damage by fire and elephant to miombo species was concentrated on adults, while these species had low ingrowth.