Complex sentence: James Bay represents the southern extent of the Arctic Archipelago Marine ecozone, while the coastal areas are primarily in the Hudson Plains, whereas the northeastern coast bordering Quebec is in the Taiga Shield ecozone.
Split into simpler sentences: James Bay represents the southern extent of the Arctic Archipelago Marine ecozone. While the coastal areas are primarily in the Hudson Plains, the northeastern coast bordering Quebec is in the Taiga Shield ecozone.