Above ground biomass, land cover change and regeneration of tree species under different grazing intensities in miombo woodlands,Tanzania
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Date
2024
Authors
Journal Title
Journal ISSN
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Publisher
Sokoine University of Agriculture
Abstract
Tanzania's livestock sector faces challenges due to overgrazing,
threatening the ecological balance of critical habitats like Miombo
woodlands. This study investigates the impact of grazing pressure on
land cover changes, tree biomass, and regeneration potential in
these woodlands of Kilosa, Kilombero, and Handeni districts.
Despite existing research on the damaging effects of overgrazing, a
comprehensive analysis specific to Tanzanian Miombo woodlands is
lacking. We address this gap by analyzing high-resolution satellite
imagery (Landsat 5 TM & 8 OLI) from 1995 to 2021 to quantify land
cover changes across the study areas.
Field surveys were conducted to assess grazing intensity,
aboveground biomass (AGB), and tree regeneration within
representative Miombo woodland sites. Allometric models estimated
tree-level AGB, which was then scaled to calculate plot-level AGB
(tonnes/ha). Statistical analyses explored relationships between
grazing intensity and land cover change, biomass dynamics, and tree
regeneration.
Results reveal a negative impact of medium and high grazing
intensities on AGB compared to light grazing. Satellite image
analysis indicates higher tree cover loss under medium grazing
(63.5%) compared to high (61.5%) and light grazing (23.2%)
between 1995 and 2022. Additionally, grazing intensity significantly
affects tree regeneration (number, species richness, diversity, and
evenness) (p < 0.05).
These findings show the damaging effects of overgrazing on
Tanzanian Miombo woodlands. This knowledge can inform
sustainable grazing practices, collaborative management strategies,
and efforts to mitigate forest cover loss. Further research could
explore
optimal
grazing
levels
and
develop
specific
recommendations for policymakers and land managers.
Description
MSc Dissertation
Keywords
Biomass, Land cover, Tree species, Grazing, Miombo, Woodlands