Coastal dune systems are very sensitive geoindicators that reflect rapid geological change and its environmental consequences. Detailed analysis of the long-term trends in the dynamics of the shifting Holocene dunes using satellite images and ground survey data revealed that during the 20th century, erosion, flattening, and sylvanization of the dunes along the entire 33-km length of the still-active Great Curonian dune ridge was taking place at a very rapid rate and scale. Flattening of the shifting dune ridge because of exhaustion of sand supplies, plant succession, and human activity is the main dune management problem, important both for the maintenance of landscape diversity and for the conservation of the traditional heritage features of the Curonian Spit as a World Heritage site. A radical shift in dune-handling paradigm—from forestation to the removal of pine plantations—and the enhancement of dune dynamism is critically needed for the protection of the Great Curonian shifting dune ridge.