ISLANDS - SOIL PATCHES AND PLANT COMMUNITY DYNAMICS ON A NEW OIL SANDS RECLAMATION DESIGN 1

The goal of land reclamation after oil sands mining in the boreal forest of northern Alberta, Canada is to re-establish functioning forest ecosystems, including the development of a natural plant community. Reclamation practices include the use of operational reclamation soils derived from upland forest soils (referred to as forest floor-mineral mix (FFMM)), which has higher plant diversity, and lowland based peat-mineral mix (PMM), which has greater tree regeneration. Building from experience in forest harvesting practices and natural landscape patterns, the "Islands" reclamation concept was put into practice in a new reclamation area established in 2015 with patches or islands of differing sizes and shapes of FFMM placed within a matrix of the more abundant PMM. These islands of FFMM are intended to serve as lifeboats and colonization centres for native biota. Initial studies are focusing on determining the optimal size and spacing of the FFMM patches. Plant species area curves were developed and show that patch sizes of at least 671 - 960 m 2 are recommended to allow initial establishment of native plant species, and in particular woody species, with smaller patch sizes favouring non-native weedy species. Initial spatial patterns indicate no relationship between plant species richness and distance to FFMM - PMM soil boundary with the rate and distance of spread of native plants from the FFMM patches being an important monitoring consideration in future years. This work on the Islands approach will help in the development of more efficient and effective reclamation practices which take advantage of the ecological differences in available reclamation soils.