Deforestation drivers and effects of livestock grazing on forest structure and composition in the coastal forests of Kilwa District Tanzania
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Date
2024-05
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Sokoine University of Agriculture
Abstract
Coastal forests of Eastern Africa hold considerable importance for
the communities residing adjacent or within including forage
provision to both domestic and wild ungulates among other
ecosystem services. However, the coastal forest ecosystems of
Tanzania are facing pressure due to increasing detrimental
anthropogenic activities including massive livestock influx which may
affect its integrity and vital roles. The present study aimed to provide
a better understanding of the effects of livestock grazing on the
woody plant composition, vegetation structure, and regeneration
capacity of the coastal forests and local communities’ perception of
the contribution of livestock grazing and other human activities to the
change in land cover of landscape comprising coastal forests in
southern Tanzania. The study was conducted in Kilwa District, Lindi,
Southern Tanzania. Data collection involved a household survey and
ground vegetation survey and analysis of Landsat satellite images.
Results indicated that coastal forests at the study site had
experienced a 45% decline in cover between 2007 and 2022 at the
rate of -3% loss per year, to which interviewed respondents also
agreed. Further, 29% of farmland area has increased within the past
15 years. The results revealed further that crop cultivation, livestock
grazing, and charcoal production are among the major drivers for
forest cover loss. Furthermore, results indicated no and low grazing
intensity had higher plant species richness, density, and diversity
contrary to moderate and heavy grazing intensities. The moderate
and heavy grazing intensities also had low seedling density and
diversity. Livestock grazing has also negatively affected the stem
distribution of seedlings, saplings, poles, and trees indicating
degradation of the coastal forests. It can be concluded from these
findings that grazing affected plant species composition, diversity
indices, and stem densities in the studied coastal forests. Low
grazing intensity had higher diversity indices, stem density, and
regeneration status similar to or better than no grazing. Therefore,
low grazing is suitable under low stocking rates for livestock due to its insignificant effect on woody species structure, composition and
regeneration potential/seedling, and sapling density. It is suggested
that urgent interventions are required to ensure controlled grazing
that halts heavy grazing and detrimental human activities in the
coastal forests within village lands. Also, further research involving
large-scale study and long-term cattle and goat grazing experiments
with varied grazing intensities/stocking rates to discern proper
carrying capacities and effects on biophysical factors such as soil,
water, vegetation, and wildlife resources in the landscapes with
ample coastal forest resources. This information is useful for
informing sustainable conservation strategies of coastal forests at
the study site and elsewhere with similar environments.
Description
MSc Dissertation
Keywords
Forest disturbance, Land cover and land use changes, Livestock migration, Ecosystem services.