The phytogeography of moist forests across Eastern Zimbabwe

Abstract

Background and aims – During the 1970s, a comprehensive survey of moist forest areas across Zimbabwe’s Eastern Highlands was carried out, from Nyanga in the north to Chirinda Forest in the south. All tree stems 8 cm diameter or greater in both canopy and sub-canopy layers were measured in 176 quarter-hectare plots, and plots were then classified into 12 altitude-related forest types. The aim of the present study is to categorise the woody species recorded in these plots in terms of their chorological status. The findings are compared to similar analyses from moist forests across Malawi.Material and methods – All tree species recorded during the initial survey were listed and placed into 12 described chorological (phytogeographical) categories based on their continental distribution. Their occurrence across the 12 previously described forest types is given. Key results and conclusions – A total of 211 tree species was recorded from 176 plots. Most species (86, or 40.8%) are Afromontane endemics or near-endemics, while 48 species (22.7%) are Guineo-Congolian linking, 31 (14.7%) are Eastern endemic or near-endemics, and 16 (7.6%) are sub-Afromontane endemics or near-endemics. The remainder comprise African linking and Zambezian species. This shows that species of the moist forests of eastern Zimbabwe form a complex phytogeographical mix. While Afromontane species dominate at high altitudes, Guineo-Congolian and Eastern species become more common at lower altitudes. In terms of proportions of chorological categories, results were found to be similar to those from forest studies in Malawi.