Diversity, population structure and regeneration status of woody species in different habitats in Maun Educational Park, northern Botswana

Abstract

The diversity and population structure of woody species at Maun Educational Park (MEP) was investigated from June to July 2018. A total of 23, 18 and 30 quadrats of 20 × 20 m size were laid down at 50 m intervals along a transect line at riparian, seasonal floodplain and upland habitat, respectively. The Shannon diversity index and evenness were 1.87 and 1.54 in the riparian habitat, 2.01 and 0.77 in the seasonal floodplain habitat, 0.71 and 0.80 in the upland habitat. The species richness was 22, 14 and 19 in riparian, seasonal floodplain and upland habitat, respectively. The patterns of population structures of the woody species revealed that 32% and 21% of the woody species recorded in riparian and upland habitat, respectively, had a “reverse J-shaped” distribution, indicating a healthy or good regeneration. Vachellia tortilis and Combretum imberbe showed healthy regeneration in both riparian and upland habitat. Healthy regeneration in these species was attributable to their adaptive and defence mechanisms to herbivory. Most of the woody species showed either hampered seedling recruitment or hampered regeneration as a result of anthropogenic disturbance and herbivory. Almost all of the woody species (86%) in the seasonal floodplain habitat exhibited relatively good seedling recruitment and discontinued regeneration in the subsequent middle and higher diameter classes, suggesting that flooding inhibited regeneration of woody species.