Trade-offs between Plant Biodiversity and Management Intensification

Agroforestry, because of its diverse options and structure sometimes believed to be more suitable for conserving biodiversity, particularly in tropical landscapes, where rural people depends heavily on nature for sustaining their livelihoods. However, since agroforestry systems are subjected to some level of cultural management it is also critical to understand how cultural managements and different level of intensification affects biodiversity in such agroforestry landscapes. We conducted an exploratory survey on four contrasting agroforestry systems; viz., betel-vine (Piper betel) based agroforestry, lemon (Citrus limon) based agroforestry, pineapple (Ananas comosus) based agroforestry, and short-rotation swidden cultivation in a tropical forest patch of Bangladesh, to assess the response of plant community to different level of management intensification. A unique management intensification gradient was constructed identifying a total of 11 locally followed cultural practices spread across the studied agroforestry systems. We recorded 173 plant species (61 tree, 42 shrub, 47 herb, 18 climber and 5 orchid species) from forty 100 m2 plots established in four agroforestry systems. The Shannon-Weiner biodiversity index calculated was higher for betel-vine agroforestry (3.3), followed by 2.9 for lemon/horticulture agroforestry, 2.2 for pineapple agroforestry and 1.9 in short-rotation swidden agriculture system (comparable to 2.7 for forest). Species evenness index for tree was also higher in betel-vine agroforestry system (0.79). A simple linear regression was performed for each of the studied agroforestry systems to realize the response of different plant functional groups to a weighted management intensification value. It was observed that, plant biodiversity is highly sensitive to management intensification, and the response of different plant functional groups to different management regimes varied considerably on types of agroforestry systems, and the kind of expected products