CENTERVILLE – The stretch of Louisiana coast between the Wax Lake Outlet and Atchafalaya River deltas is a tangle of contradictions. Much of Louisiana’s coastal wetlands are being eroded away. But not here. These deltas are growing. The plants that play a starring role in that growth can’t stand saltwater. Yet tides exert a powerful influence on how and where they take root. Coastal erosion often is blamed on the work of humans: flood control levees that divert the sediment that should enrich coastal wetlands, canal-cutting that allows saltwater into freshwater marsh, even the introduction of the nutria, whose gluttony robs the ...