Do environmental variables and overstory communities affect the spatial pattern of understory vegetation? Lessons from Monotheca buxifolia (Falc.) A. DC. forests in Pakistan

ABSTRACT The importance of understory vegetation cannot be denied as an integral component of forest ecosystems, but there is a dearth of studies to explore the effects of environmental variables and canopy species on its diversity and composition. Here we investigated the effects of environmental variables and overstory stand structure on the understory vegetation in old-growth Monotheca buxifolia dominated forests with considerable co-dominance of other broadleaved by using ecologically standardized data collection methods across Pakistan. Multivariate analyses were used to examine the vegetation composition and different species assemblages with multiple influencing variables. We found a total of 58 understory species belonging to 55 genera and 30 families mostly representing pluriregional (33.89 %) chorological affinities with therophytic (17 species) life-form dominance and microphyll (34.48 %) leaf-size spectrum. Likewise, significant differences were observed in species richness and diversity indices between different understory community types. Attributes such as elevation, aspect, soil properties, and tree canopy structure were most strongly correlated with the Redundancy Analysis (RDA-ordination), indicating that several factors exert the strongest influence and explained the spatial pattern of understory vegetation. The findings of this research can assist forestry resources managers, forest biologists and ecologists in restoration and conservation plans for understory vegetation in the region.