Effect of transportation infrastructure on forest plant diversity and soil properties in Lawachara National Park, Bangladesh

Abstract

Transportation infrastructure has bought many blessings for human civilization, although its negative influences, especially on a forested landscape should be heeded with prime concerns. In this study, we studied, how railway track perforating through Lawachara National Park affecting the nearby vegetation alpha (α) and beta (β) diversity and composition and soil properties, and whether the effects are active until a certain distance into the forest interior. Total 32 plots in 8 transect lines perpendicular to the railway are laid with 4 plots at 10 m, 40 m, 70 m and 100 m distances. Tree and tree regeneration α and β-diversity and composition, and soil organic matter and pH were assessed at each of these plots. Our results showed that, soil organic matter and pH, as well as α-diversity indices were significantly (P < .05) higher in plots near the railway track than forest interior parts in case of both tree and tree regenerations. But the β-diversity did not vary significantly (P > .05) with distances. High amount of organic matter in outermost plots was maybe due to the decomposition of litterfall and debris where increased pH value was due to presence of high amount of calcareous substances and plant residue. As the α-diversity of plant decreased with increasing distance from the railway track and in most cases the value decreased until 70 m distance, indicated that the influence of the railway tracks maybe prominent up to 70 m. So, to minimize this effect of vegetation structure proper steps such as careful planning in road building, afforestation using the native species and evaluation of the necessity of infrastructure and possible alternatives to it should be assessed.