Assessment of Plant Diversity in Forest, Agroforest and Social Forestrty in the Degraded Madhupur Sal Forest of Bangladesh

Abstract

The rich plant biodiversity found in tropical regions faces significant threats due to extensive human activities. Factors such as deforestation, habitat deterioration, human settlement, excessive resource exploitation, the introduction of invasive species, pollution, and the interconnected effects of global climate change collectively contribute to a substantial negative impact on biodiversity in these areas. The study aimed to assess plant diversity in Madhupur Sal Forest, Bangladesh, comparing agroforestry, social forestry, and natural Sal Forest sites. Using 90 random 10 × 10 m² plots, 47 species were recorded, including 31 trees, 5 shrubs, 6 herbs, and 5 climbers. Anacardiaceae, Arecaceae, Euphorbiaceae, and Fabaceae were prominent families, each with a species richness of 3. Agroforestry exhibited the highest species richness (14), Shannon-Wiener index (1.37), and Simpson's index (2.41) among plantation sites, surpassing social forestry. Social forestry, however, showed higher tree stand density (1673 trees/ha), tree basal area (28.67 m²/ha), and species evenness (0.67) than agroforestry. The natural Sal Forest site displayed the highest species richness (33), tree basal area (41.21 m²/ha), Shannon-Wiener index (2.15), and species evenness (0.78). Overlapping species occurred between agroforestry and social forestry (5 species), and agroforestry and natural Sal Forest (1 species), resulting in a higher similarity index (19%) for the former. No species overlapped between social forestry and natural Sal Forest. The study concluded that natural Sal Forest exhibited the highest diversity (2.15), while agroforestry proved beneficial for biodiversity compared to bare land.