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Effects of different disturbance regimes on grass and herbaceous plant diversity and biomass in Zimbabwean dambo systems

Matayaya, Grace, Wuta, Menas, Nyamadzawo, George
TheInternational journal of biodiversity science, ecosystem services & management 2017 v.13 no.1 pp. 181-190
burning, conventional tillage, gardens, grasses, herbaceous plants, herbs, phytomass, plowing, seed germination, species diversity, Zimbabwe
This study examined the species richness, diversity, biomass of grasses and herbaceous plants and seed germination in plots with contrasting disturbance regimes established in a dambo garden, in Chiota, Zimbabwe. The disturbance regimes were burning, clipping, clearing and conventional tillage and were applied annually to each subplot from 2010 to 2012. It was hypothesised that burning increases biomass, species richness and diversity of plants while reducing seed bank diversity. Clearing, clipping and conventionally tilling negatively affect biomass, species richness and diversity. The Shannon–Wiener Index was used to estimate species diversity and the average values obtained ranged 0.53, 0.85, 0.91, 1.3 and 1.70, for the undisturbed, burnt, conventionally tilled, clipped and cleared plots, respectively. The biomass in the experiment ranged from 0.92t ha–¹ for the ploughed plot to 20.92t ha–¹ for the undisturbed plot. The species richness for the plants decreased in the following order; clearing>conventional tillage>burning>clipping>undisturbed. These results show that disturbance regimes increased species richness but however decreased plant biomass. It is apparent that the management practice that ensures maximum biomass of grasses and herbs in dambos is maintaining them in their natural state. However, clearing seemed to improve species diversity compared to maintaining the dambo in its natural state.EDITED BY Alexander van Oudenhoven and Patricia Balvanera