Vegetation cover changes due to artisanal and small-scale gold mining in Bukombe-Mbogwe forest reserve in Geita region, Tanzania

Abstract

Bukombe-Mbogwe Forest Reserve (BMFR) has substantially lost its vegetation cover following Artisanal and Small-scale Gold Mining (ASGM). The study aimed at examining vegetation cover changes in BMFR and surrounding villages due to ASGM in Mbogwe District. Purposive and random sampling were employed obtaining 138 respondents. Data was collected through remote sensing, participant observation, questionnaire survey, key informant interviews and focus group discussions. Landsat images of three window periods (1984, 2002 and 2020) were analysed qualitatively and quantitatively using Normalized Difference Vegetation Index (NDVI) and supervised classification of Maximum Likelihood (ML) algorithm techniques respectively. Descriptive and content analysis were conducted for quantitative and qualitative socio-economic data respectively. By using NDVI technique, median values decreased in BMFR from 0.57 (dense vegetation) to 0.34 (shrubs and grasslands). Land use/cover changes (LULCC) for 1984 to 2020 proved that there was decrease in dense vegetation from 46.4% to 25.62%, bare-land from 43.23% to 20.06% and increase in sparse vegetation from 9.4% to 46.86% and built-up land from 0.97% to 7.46%. Logs for pit construction were extracted from BMFR by 67.5%. Therefore; ASGM has negatively changed vegetation cover in BMFR and surrounding villages. The paper recommends increasing protection in BMFR by employing Joint Forest Management (JFM).