An investigation into the fine-scaled variation in tree diversity and the varied architecture of Colophospermum mopane in the Mopaniveld

In this study we investigate the drivers behind variation in species richness and diversity at a fine
scale in the Mopaniveld (i.e. what causes monospecific vs. multispecies stands?) and the drivers
behind variations in stand and individual C. mopane architectures (height, basal area,
multistemmedness). We hypothesize that the basic compositional structure of the plant
communities is determined by physical and edaphic soil characteristics. In the absence of
disturbance, competition should determine densities and stand architectures of C. mopane given the
abiotic template. In highly disturbed savanna environments the effects of competition are most
likely less obvious, and densities and stand architectures of C. mopane would be determined by its
response to the disturbance regime. Our data indicated the presence of catenal sequences.
Plots with sandy soils were located at higher elevations and had lower conductivity, calcium and
carbon concentrations than plots with clay soils (U=57, P=.022; U=45, P=.01; U = 56, P = .02;
U=35, P<.005). Variation in species richness and diversity at a fine scale in this part of the
Mopaniveld appears to be determined by catenal sequences as species richness and diversity was
higher in plots with sandier soils (U=52.5, P<.05 and U=62, P=.05 respectively). C. mopane
appears to grow in higher densities on clay soils (U=66, P<.055), but grows larger on sandy soils
(Beta=0.652, P<.05 and Beta =0.553, P<.01 respectively) with high calcium concentrations
(Beta=0.487, P<.05 and Beta =0.463, P<.05 respectively). Variations in disturbance regimes and
competition at the catenal scale could be important in determining stand and individual C. mopane
architecture.