Human activities outcomes on the composition of woody plant species of Ngarama Southern Forest Reserve in Kilwa District, Tanzania

Abstract

Abstract. Jilala ZJ, Mwakalukwa EE, Chamshama SAO. 2019. Human activities outcomes on the composition of woody plant species of Ngarama Southern Forest Reserve in Kilwa District, Tanzania. Asian J Ethnobiol 2: 108-118. This study evaluated the effects of human activities on the composition of woody plant species of the Ngarama Southern Forest Reserve (NSFR) in Kilwa District, Tanzania. Vegetation research was conducted in 40 systematically arranged rectangular test plots, aligned in five transepts over 2,070 ha forest. Information recorded in each plot included: species name, diameter at breast height (DBH), the height of selected timber species with a diameter ? 5 cm, and various indicators of human disturbance. Landsat TM and ETM+ images from 1995, 2000, and 2011 were used to locate and quantify the land cover change in the NSFR over the past 20 years. Inventory data was analyzed using Microsoft Excel and R software, while Landsat images were analyzed using the academic software ILWIS 3.0. About 126 plant species belonging to 34 families have been identified. Trees contributed 63% (28 families), and shrubs 37% (17 families). The Shannon-Wiener index and Simpson's diversity indices were 3.95 and 0.03, respectively. In addition, a mean stem density of 667 ± 19 stems ha-1 and a basal area of ??13.11 ± 0.34 m2 ha-1 were obtained. Twenty-three stumps (7 ± 3 ha-1 stems) with a mean baseline area of ??0.24 ± 0.09 m2 ha-1 stumps were removed, indicating ongoing anthropogenic disturbances in the forest. Other indicators of disturbance recorded were damage from fire (50%), paths / roads (13%), silage (8%), lumber/planks/pile harvesting (8%), cultivation (5%) and logging ( 8%). Although NSFR has a decent species richness and is well-diversified, there has been a consistently negative change in forest cover concerning low trunk density, average tree height, average DBH, and basal area, indicative of anthropogenic disturbance. Conservation measures are recommended to improve governance and accountability regarding accountability for intensive forest resource management.