Figure 1.
A schematic representation of the exclosure experiment with the three treatments.
(1) open access, accessible for all herbivores (+E+N, open bars); (2) partial exclosure, elephant excluded, nyala present (−E+N, diagonal hatching); (3) full exclosure, both elephant and nyala excluded (−E−N, grey bars) (not to scale). The sets of three treatments were replicated 12 times.
Table 1.
List of 26 species included in the analyses.
Figure 2.
Mean density (trees/ha) per height class (i.e. seedlings: ≤0.5 m; saplings; 0.51–1.5 m) for all 26 species combined per treatment.
Open access (+E+N, open bars), partial exclosure (−E+N, diagonal hatching) and full exclosure (−E−N, grey bars). The bars indicate 95% confidence intervals of the means. N = 12 replicates per treatment.
Figure 3.
Mean density (trees/ha) per diameter size class (i.e. seedlings: ≤1 cm; saplings; 1–4 cm) for all 26 species combined per treatment.
Open access (+E+N, open bars), partial exclosure (−E+N, diagonal hatching) and full exclosure (−E−N, grey bars). The bars indicate 95% confidence intervals of the means. N = 12 replicates per treatment.
Figure 4.
Mean seedling density (trees/ha) for all 26 species combined per treatment per sampling year.
Open bars: 2005; grey bars: 2007. The bars indicate 95% confidence intervals of the means. N = 7 replicates for the open access treatment (+E+N) and N = 12 for the partial (−E+N) and full exclosure (−E−N).
Figure 5.
Mean stem density (stems/ha) per height class (i.e. seedlings: ≤0.5 m; saplings; 0.51–1.5 m) for all 26 species combined per treatment.
Open access (+E+N, open bars), partial exclosure (−E+N, diagonal hatching) and full exclosure (−E−N, grey bars). The bars indicate 95% confidence intervals of the means. N = 12 replicates per treatment.
Figure 6.
Size distribution curves of three common Sand Forest species in the three treatments.
a, height class distribution (i.e. seedlings: ≤0.5 m; saplings; 0.51–1.5 m); b, linear regression of diameter class distribution. Open access (+E+N, open bars, grey circles and lines), partial exclosure (−E+N, diagonal hatching, red circles and lines) and full exclosure (−E−N, grey bars, black circles and lines). The bars (a) and dotted lines (b) indicate 95% confidence intervals. N = 12 replicates per treatment.
Figure 7.
Size distribution curves of three characteristic Sand Forest species in the three treatments.
a, height class distribution (i.e. seedlings: ≤0.5 m; saplings; 0.51–1.5 m); b, linear regression of diameter class distribution. Open access (+E+N, open bars, grey circles and lines), partial exclosure (−E+N, diagonal hatching, red circles and lines) and full exclosure (−E−N, grey bars, black circles and lines). The bars (a) and dotted lines (b) indicate 95% confidence intervals. N = 12 replicates per treatment.