English: Boardwalk onto the dunes Boardwalks have been constructed here to help walkers to cross particularly fragile areas without damaging the vegetation. On this wet morning the planks are wet and quite slippery. One of the footpaths leading into the Holkham Nature Reserve can be accessed from the A149 east of Burnham Overy Staithe. The first section of this path leads through marsh pastures > https://www.geograph.org.uk/photo/908439 - https://www.geograph.org.uk/photo/908447 which were reclaimed in the 18th and 19th centuries, beginning at Burnham Overy in 1639 and ending with the construction of the sea wall at Wells in 1859. Further seawards, the marsh pastures turn into saltmarsh > https://www.geograph.org.uk/photo/908459 the middle and upper levels of which are covered with plants such as sea aster and sea lavender. Leaving the saltmarsh behind, extensive dune systems form an impressive barrier between the saltmarsh and the foreshore. The dunes at Holkham sit on old shingle ridges and their landscape is continuously changing due to the effects of wind and water. The coast to the east is eroding whereas shingle banks are building up above the tideline where windblown sand gathers. The high dune islands on the foreshore have appeared in the last sixty years. Amongst the first plants to colonise newly formed dunes are sand couch grass, sea sandwort and marram grass. Flowers that thrive in extreme conditions, such as bee orchid and carline thistle, can be found growing on mature dunes. The dunes provide shelter and nesting places for many bird species of birds and the reserve accounts for 7% of the British population of Little terns. http://www.holkham.co.uk/naturereserve/dunes.html