Status and progress of forest landscape restoration of the Bunduki Gap in Uluguru nature forest reserve, Morogoro, Tanzania.
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Date
2024
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Sokoine University of Agriculture
Abstract
Forest Landscape restoration is a global imperative, addressing
ecological, social, and climate challenges. In Africa's drylands, FAO
identifies a critical need to restore 221 million hectares. In response,
African nations, including Tanzania, pledged through the African
Forest Landscape Restoration Initiative (AFR100) to restore 5.2
million hectares by 2030. However, the historical deforestation and
degradation caused by illegal logging, agriculture expansion, and fires
persist. In 2008, Tanzania government evict farmers from the Bunduki
gap to enhance biological connectivity within the Uluguru nature
forest reserve. Despite this, studies on the progress and composition
of land cover at Bunduki post-eviction are scarce. Such information is
crucial for justifying and supporting ongoing restoration initiatives
amid global demands for sustainable forest management and climate
change mitigation.
Therefore this study assesses pre and post-eviction land cover
changes at the Bunduki gap using high-resolution satellite images
(Quickbird 2005, Worldview 2011, Pleiades 2017). Employing
supervised image classification with a random forest algorithm on
Google Earth Engine, assesses classification accuracy, analyzes
changes in land cover classes, tracks their persistence and
trajectories, and examines spatial distribution for the periods 2005-
2011 and 2011-2017. Vegetation composition was evaluated in terms
of species richness, Important value index, diversity indices (Shannon
and Simpson’s), and hierarchical clustering, while structural
characteristics were analyzed in terms of diameter class distribution
across forest part.
The pre and post-eviction land cover assessment reveals dynamic
transformations in the study area between 2005, 2011, and 2017.
Forest coverage increased from 1.74% in 2005 to 51.80% in 2017,
while bushland, grassland, and bare land exhibited contrasting
trends. The main result is the replacement of bare land, grassland,
and bushland by forest land cover. The rate of this replacement
differs temporally and spatially across the gap. Vegetation composition analysis revealed 1,149 individuals representing 94
species, 47 families, and 89 genera. The majority of species (52.13%)
were common across all forest part, with the Bunduki Gap exhibiting
25.53% unique species. Three distinct communities were identified,
displaying significant differences (R=0.64, P<0.005), although no
significance difference was observed in diversity indices (P>0.005).
Diameter class distribution of the shared and unique species with
high importance value index varies significantly across forest part
(P < 0.0438), with higher diameter classes prevailing in Uluguru North
and South, and lower and medium classes more prevalent in the
Bunduki Gap, albeit with fewer instances in Uluguru North and South
respectively. The study concludes there is successful forest recovery
post eviction and there are similarities in emerged plant species
across the forest part with varying diameter distributions, the
presence of unique species and distinct communities underscores the
imperative for further investigation to mitigate the spread of invasive
species within the reserve
Description
Dissertation
Keywords
Land cover change, Conservation Monitoring, Biological connectivity, Species diversity, Evictions