Diversity, composition and population structure of vegetation in Palabek settlement and adjacent areas in Lamwo District Uganda

Abstract

Refugees in Lamwo district, Uganda, were settled at Palabek settlement since 2017, interacting with and partly depending on the natural resources for survival. The study assessed the pattern of change in plant species diversity, composition, density and population structure of tree species.

Six line transects were established radiating from the center of the settlement outwards to the north, east, south, west north east and south west upon which nested sample plots were laid. Five line transects were 8km each and one line transect was 3km due to difficulties accessing the area. The settlement area was in 4km radius and 4km buffer was considered for the areas outside the settlement and due to their closeness to the settlement. Systematic sampling was adopted in the study to ensure an even spread of the sample plots throughout the study area.

A Pearson correlation was used to analysis the relationship between the study variable and the distance from the settlement outwards, Shannon-Weiner diversity index was used to calculate the diversity of the plant life forms and PCA used to determine species associated with settlement.

A total of 255 plant species belonging to 181 genera and 43 families were recorded during the study. The diversity index was 3.6, 3.0 and 2.7 for shrubs, trees and herbaceous plants respectively.

The study findings revealed that species diversity of trees, shrubs and herbs generally increased from the settlement outwards although the increase was not statistically significant with increase in sampling effort. The population structure of the trees in the sampled plant community exhibited a reverse J-shaped distribution, three tree species of conservation concern were found to be threatened in the study area.

Therefore, planning for sustainable harvesting of wood products is of paramount importance to safeguard the vegetation in the study area from loss. Encouraging practices like Agroforestry, establishment of woodlots, energy saving technologies use will help save the vegetation from degradation in Palabek settlement and surrounding areas.