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Reclamation following anthropogenic disturbance often aims to restore native plant biodiversity. Strong laws are in place to regulate mine-land reclamation following coal extraction which includes components of required re-spread (topsoil/subsoil) depths, seed mixes and slopes among many others. These laws mandate recently mined areas be reclaimed back to productive landscapes where all aspects of the ecosystem can flourish. Subsoil and topsoil are re-spread and increasingly planted with diverse warm and cool season grass mixes, however historically excluding forbs. Both soil and the diverse seed mixes are typically spread homogeneously across landscapes creating high local-scale diversity (alpha), but low landscape-scale diversity (beta). Existing seed banks in direct re-spread areas of topsoil, and seed rain are thought to augment the vegetation successional trajectories and increase both alpha and beta diversity over time. Our objective was to evaluate the small and large-scale vegetation patterns across a 40-year reclamation gradient. We hypothesized that both alpha and beta diversity would increase with time since reclamation. Plant communities were sampled on 18 post-mine reclaimed and five native reference sites in central North Dakota mixed-grass prairie. Species composition and canopy cover were recorded at two locations in each reclamation year using a 1x1-m2 quadrat at 2-m intervals along a permanently marked 70-m transects. We determined the inherent small scale dissimilarity of vegetation along with the average patch size and the highest mean dissimilarity between patches using dissimilograms based on the relative Sørensen dissimilarity index in PC-ORD 6.0. Relative plant community patch size on reclaimed lands over four decades will indicate the landscape-level success of the current ecosystem-based reclamation strategy.