A compartive study of vegetation structure and visibility at Wild Dog (Lycaon pictus) kill sites in and outside Hwange National Park

Abstract

The objective of this study was to compare vegetation structure and visibility at sites at which wild dogs (Lycaon pictus) had killed kudu (Tragelaphus strepsiceros) and impala (Aepyceros melampus). The kill sites, within Hwange National Park (HNP) and the adjacent forest areas, were recorded by Gregory Rasmussen between 1997 and 2002. Vegetation structure at each kill site was characterized in five 10 m x 10 m plots, one at the kill and the other four randomly placed within 1000 m from the kill site at each of the four major compass directions (North, South, East, West). Shrubs were characterized in a 5 m x 5 m quadrant within the 10 m x 10 m plot. Grass height was estimated in three randomly thrown 0.5 m x 0.5 m quadrats within the 10 m x 10 m. Twenty random non-kill sites were generated and measured in the same way and the following vegetation attributes were measured at each kill site and non-kill site: tree canopy cover, basal area, tree canopy volume, tree height, tree density, shrub height, shrub volume, and shrub density and grass height. The results of this study revealed that vegetation cover was denser outside the park (F= 6.658; P < 0.001). Visibility was also lower outside the park (F = 32.882; P < 0.001). Dogs selectively hunted impala in bushed grassland within the park and in bushed woodland outside park. Kudu were killed in the same vegetation types within and outside the park but in much taller and denser vegetation than impala (F = 6.847; P < 0.05). Grass height was insignificantly different between the two sides and also between the two species. Random non-kill sites vegetation characteristics differed significantly from the kill sites (F = 9.389; P < 0.05). Visibility was influenced by shrub height than any other vegetation characteristic and from this study it was concluded that the movement of wild dogs outside Hwange National Park can be explained by differences in vegetation structure within and outside the park.