Influence of elephant (Loxodonta africana Blumenbach) on Baikiaea plurijuga dominated woody vegetation around natural and artificial watering points in the northern part of Hwange National Park, Zimbabwe

Abstract

The extent of elephant damage on shrub and mature Baikiaea plurijuga was investigated around artificial and natural watering points in the Main Camp area of Hwange National Park. Damage was scored on a percentage basis for B. plurijuga and other associate species. Level of damage was determined by height of plant and nature of damage. Structural changes to B. plurijuga were also investigated between artificial and natural watering points at varying elephant occupancy gradients from a watering point.

Elephant damage on B. plurijuga recruits (1-3m) around artificial watering point was 26.5%, 10% and 9.75% in high, moderate and low zones of elephant occupancy respectively. Elephant damage to mature B. plurijuga (>3m) around artificial watering points amounted to 18%, 14% and 8% in high, moderate and low zones of elephant occupancy. Elephant damage to overall woody vegetation in B. plurijuga dominated woodlands around artificial watering points was 23%, 15% and 11% in high, moderate and low zones of elephant occupancy respectively. Damage to recruits, mature B. plurijuga and overall woody vegetation decreased linearly with distance from artificial watering point.

Elephant damage on B plurijuga recruits around natural watering points was 11.5%, 10% and 8% in high, moderate and low zones of elephant occupancy respectively. Elephant damage on mature B. plurijuga around natural watering points was 14%, 9% and 8% in high, moderate and low zones of elephant occupancy respectively. Elephant damage to overall woody vegetation in B. plurijuga dominated woodlands was 18%, 13% and 10% in zones of elephant occupancy respectively. Damage to mature B. plurijuga and overall woody vegetation decreased linearly with distance from natural watering point while damage to recruits did not change linearly with distance from water.

Statistical analysis showed that artificial watering points are associated with higher damage to B. plurijuga recruits and overall woody vegetation within ¡Ü1km radius from water than natural watering points. Such high damage resulted in lower canopy cover closer to artificial watering point and relatively higher canopy cover around natural watering point. Other changes associated with increasing distance from artificial watering points were increase in canopy cover and decrease in woody species diversity. Changes associated with distance from natural watering points were increase in canopy cover, mean basal area of B. plurijuga shrubs, mean height B. plurijuga shrubs and decrease in diversity. Woody species diversity was higher around natural watering points than around artificial watering points.