Effects of stand characteristics on tree species richness in and around a conservation area of northeast Bangladesh

We investigated the effect of tree cover,forest patch and disturbances on tree species richness in a highly diverse conservation area of northeast Bangladesh.A systematic sampling protocol was adopted and 80 sub-plots from twenty five 1 ha plots were used for the vegetation survey.Linear regression analysis was performed to understand the effect of patch area,disturbances and tree cover on tree species richness.Ordination using Redundancy analysis(RDA) and Non-metric Multi Dimensional Scaling(NMDS) were also performed to explore the tree species compositional similarities along the stand characteristics gradient and locations of the sample plots.Our study revealed that,forest patch size has greater influence on species richness.Areas with medium level of disturbances have shown greater species richness.In constrained ordination the selected explanatory variables regulated the richness of common species.Our findings can be useful for better forest management and restoration of landscapes of conservation needs using ecologically important species.

Tree species diversity in relation to environmental variables and disturbance gradients in a northeastern forest in Bangladesh

Biodiversity has become an issue of global attention because of growing awareness of its importance and its rapid depletion worldwide.Diversity of tree species in relation to environmental and disturbance gradients was examined in three managed forests.Trees were randomly sampled in a survey of 75 circular plots(radius=13 m)with 5 subplots(radius=1 m).Generalized linear model analysis was used with a Poisson distribution log link function to understand the effects of variables(organic matter,organic carbon,nitrogen,potassium,pH,elevation and disturbance)on tree species richness.Canonical correspondence analysis was used to explore ecological relationships among plots.Our result found that the stand characteristics was an important influencing factor in the three forests.Our result showed that the variables had a highly positive influence on tree species richness in the three forests.In ordination,the selected variables governed the richness of tree species.Our study can help identify the most important factors that drive tree species richness in the three managed forests in Bangladesh and in similar ecosystems and inform forest management decisions for conservation according to ecological importance.