Effects of elephants on vegetation along a fenceline contrast in South Africa

We assessed the degree of damage of two common plant species, marula Sclerocarya birrea and the mountain aloe or flat-flowered aloe Aloe marlothii in two neighboring game reserves along a fenceline with respect to the presence of African elephants Loxodonta africana. One of these reserves, Thornybush, had 40-50 elephants while the other reserve, the Wits Rural facility, contained no elephants, although elephants had broken into a select region briefly during a recent drought. We measured the browse height of S. birrea relative to overall tree height and trunk circumference to establish the differences among the three different areas. We also measured the presence/absence of A. marlothii in these game reserves. We found no A. marlothii in the reserve with elephants, while this plant species was quite common where there were no elephants, despite the absence of soil differences. In the section of the Wits Rural facility where the elephants had broken in, there were considerably more damaged A. marlothii than in the scetion of this reserve without elephants. We also established the association between the size of the aloe and elephant consumption.