Structure and composition of woody vegetation along the Zambezi River floodplain and seasonal water pans in Mana Pools National Park, Zimbabwe.

Abstract

This study aimed at investigating woody vegetation structure and composition in relation to surface water availability in Mana Pools National Park (MPNP). Two study sites, namely the Zambezi River floodplain and seasonal water pans were selected. Sampling plots were systematically placed along transects from water pans at 100 m, 200 m and 500 m and thirty (30) different sampling plots of size 600 m2 were used. Statistical analysis was done using STATISTICA 7. A total of 192 woody plants from 18 woody species were recorded. More woody tree species (n = 13) were recorded around seasonal water pans as compared to the Zambezi River zone (n = 5). Results obtained from Kruskal Wallis H test showed no significant difference in height, basal area and tree density along a distance gradient from the Zambezi River to the interior (inland). Stem density and diversity showed a significant difference along a distance gradient from the Zambezi River to the interior (p < 0.05). Woody species density and diversity increased as a function of distance from the Zambezi River channel, with species diversity higher around seasonal water pans. A comparison obtained from the Mann Whitney U test between the two sampling sites showed significant difference in all structural variables. Findings of this study showed that the woodlands along the Zambezi River were more degraded as compared to those around seasonal water pans. It is an indication that the concentration of herbivores is impacting woodlands along the Zambezi River. Management should consider establishing artificial water pans around the park to minimise herbivore pressure along the Zambezi River.