Effects of Anthropogenic Disturbances on Forest Composition, Diversity, Structure, and Carbon Stock in Sayaka Forest Reserve, Mwanza Region, Tanzania

Leonard Aloice Pascal; Thadei Tarcis Rugambwa; Kelvin James Lyatuu; Paulo John Lyimo; Beatus Mwendwa

doi:10.37284/eajfa.8.1.4130

Leonard Aloice Pascal Sokoine University of Agriculture
Thadei Tarcis Rugambwa Sokoine University of Agriculture
Kelvin James Lyatuu Sokoine University of Agriculture
Paulo John Lyimo Sokoine University of Agriculture
Beatus Mwendwa Institute of Adult Education

DOI: https://doi.org/10.37284/eajfa.8.1.4130

Keywords: Anthropogenic Disturbances, Acacia Woodland, Carbon Stock, Forest Structure

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Abstract

Forests are important in biodiversity conservation, carbon sequestration, and climate regulation, yet they are threatened by anthropogenic pressures. This study assessed the effects of anthropogenic disturbances on forest composition, diversity, structure, and carbon stock in Sayaka Forest Reserve (SFR), using a systematic random sampling design of 80 circular plots (0.071 ha each). These plots were used to collect data for regenerants (< 1 cm dbh) and adult trees (≥ 1 cm dbh) as well as signs of disturbance, including farming, charcoal production, grazing, and tree cutting. The study identified a total of 13 woody species from 9 plant families, with Fabaceae as the dominant plant family. Species diversity was low among adults (H’ = 1.18) but higher in regenerants (H’ = 1.99), indicating potential for recruitment despite ongoing pressures. Mean stem density (259 ± 69 stems ha⁻¹), basal area (0.92 ± 0.26 m² ha⁻¹), and carbon stock (4.53 ± 1.34 Mg C ha⁻¹) were substantially lower than values reported in comparable East African woodlands. Generalised Linear Models revealed that farming and grazing significantly reduced species diversity, basal area, and carbon stock, while charcoal production had moderate negative effects, and tree cutting showed no significant short-term impact. These findings highlight severe ecological degradation in Sayaka Forest Reserve, emphasising the need for urgent management interventions. Strategies should focus on controlling agricultural encroachment, regulating grazing pressure, promoting sustainable energy alternatives, and implementing restoration programs to enhance biodiversity and carbon sequestration in SFR.

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