Patterns of plant species diversity across Terai landscape in north-

Abstract: The north-eastern Uttar Pradesh forms a part of Terai landscape in north India which is drained by two important tributaries of river Ganga viz., Rapti and Gandak. This landscape comprises a mosaic of cultivation, human habitation and natural vegetation that has been heavily used by people. The natural vegetation is broadly divisible into four categories viz., grasslands, secondary scrub, old-fields and forests. Of these, the grasslands were the most species-rich followed by forests, secondary scrub and old-fields. A total of 615 species of angiosperms were recorded within an area of ~10,000 km2 which represent 389 genera and 94 families. Sampling of forested landscape revealed a sizable number of rare species within frequency range of 0.001- 0.1%. These species showed very low seedling abundance and poor regeneration. The overall, landscape level diversity (γ-diversity) of the forested landscape was 4.035, to which shrubs contributed the most. The scrub vegetation was dominated by woody climbers which frequently formed thickets. Diversity of woody perennials was very low in the plantations. The composition and diversity of various grassland communities have been compared with respect to topography and canopy openings reflecting different light regimes. Suitable measures are suggested for the regeneration and conservation of existing pool of wil