Species Composition and Diversity Using Importance Value Index (IVI) and Diversity Indices Across Upland Forest Types in Cambodia: A Scoping Review

AbstractUpland forests in Cambodia (e.g., evergreen, semi-evergreen, dry mixed deciduous, and deciduous dipterocarp forests in hilly-to-montane landscapes) support high biodiversity and provide critical ecosystem services, yet evidence on tree species composition and diversity patterns remains fragmented across sites, methods, and reporting styles. This scoping review maps how the literature in Cambodia has applied Importance Value Index (IVI) and diversity indices (e.g., Shannon, Simpson, evenness) to describe forest communities, compare forest types, and interpret disturbance effects. Following established scoping review guidance and reporting recommendations, we synthesize available peer-reviewed studies and relevant technical sources that report floristic composition, dominance structure, and diversity metrics. Evidence shows that Cambodia’s evergreen and semi-evergreen forests generally exhibit higher species richness and more even composition than deciduous dipterocarp forests, which are commonly characterized by strong dominance of a few dipterocarps (e.g., Dipterocarpus and Shorea). However, comparability is constrained by variation in plot size, DBH thresholds, sampling intensity, and inconsistent reporting of IVI components. Key gaps include limited upland-specific datasets outside a few well-studied provinces, underuse of standardized diversity frameworks (e.g., Hill numbers), and insufficient integration of IVI/diversity results with environmental gradients (topography, soil, fire regimes) and disturbance histories. We provide recommendations to harmonize methods and improve future syntheses for Cambodian upland forest ecology and management.