the world. As these plants accumulate more sediments, the dunes start growing. The
roots of Marram grass can follow the growth of the dunes and their leaves are
resistant to sharp blowing sands. This system is called the primary or white dunes,
where sand transport is still one of the major driving processes. The dunes grow up to
several tens of meters forming a natural dyke between the coast and inland areas.
Where sand and wind availability are optimal dunes can grow up to more than
100 m, e.g. along the western French coast or the Namibian coastline. Where less
sand is available, the white dune area may reach only 3 m in height, as can be seen
along some Mediterranean coasts (Doody 2005). Due to the continuous aeolian
activity, white dunes are very dynamic and can move up to several meters year or
more during storms (Martínez and Psuty 2004).
On the lee side of the primary dunes, aeolian processes have a less omnipresent
impact. Here, the sediments can settle, and vegetation is able to develop. Due to soils
poor in nutrients, extremes in temperature and water availability, dune grassland
often develops in sediments with a higher lime content. In less calcareous soils
heather species become dominant. The prominent presence of mosses and lichens
give these grasslands a grey appearance, thus they are also known as ‘grey dunes’.
Open sandy spots in the grassland, some caused by the digging of rabbits or larger
grazers, are vulnerable for the dominant winds and form blow outs. If the direction of
the wind is dominant, blow outs can initiate the formation of parabolic dunes, a very
distinct pattern in the landscape. Where parabolic dunes accumulate sediments, the
blowouts may be wind excavated down to the ground water level. Here wet dune
slacks may form of even small lakes which show a remarkable diverse vegetation
(Goudie 2011).
Eventually dune grasslands accumulate organic material in the otherwise rather
sandy soil and wind and sand become a less dominant factor. Encroachment with
larger grasses and forbs as well as the establishment of shrub species lead up to the
dune forests in moderate climates or dense shrublands (e.g. maquis vegetation) in
Mediterranean areas. Also, the wet dune slacks accumulate organic matter and
eventually form an environment where birch forests can develop.
3.7 Inland Saline Habitats
In former times, inland saline habitats were often seen as badlands, and the landscape
scenery was not always perceived as beauty in the eyes of residents. However,
especially during the last decade’s scientific publications have pronounced the
uniqueness of these habitat types (e.g. Evans and Roekarts 2015, factsheets of the
European Environment Agency 2019, and pers. comm. with farmers).
Natural inland saline habitats can occur under arid or semi-arid conditions where
evaporation causes increasing salt concentrations, and in regions where saline or
alkaline waters flow out of the geological surface (salt springs). Such habitats may
also occur where excavation material of mining activities is deposited (Pernik and
292
C. Hobohm et al.
roots of Marram grass can follow the growth of the dunes and their leaves are
resistant to sharp blowing sands. This system is called the primary or white dunes,
where sand transport is still one of the major driving processes. The dunes grow up to
several tens of meters forming a natural dyke between the coast and inland areas.
Where sand and wind availability are optimal dunes can grow up to more than
100 m, e.g. along the western French coast or the Namibian coastline. Where less
sand is available, the white dune area may reach only 3 m in height, as can be seen
along some Mediterranean coasts (Doody 2005). Due to the continuous aeolian
activity, white dunes are very dynamic and can move up to several meters year or
more during storms (Martínez and Psuty 2004).
On the lee side of the primary dunes, aeolian processes have a less omnipresent
impact. Here, the sediments can settle, and vegetation is able to develop. Due to soils
poor in nutrients, extremes in temperature and water availability, dune grassland
often develops in sediments with a higher lime content. In less calcareous soils
heather species become dominant. The prominent presence of mosses and lichens
give these grasslands a grey appearance, thus they are also known as ‘grey dunes’.
Open sandy spots in the grassland, some caused by the digging of rabbits or larger
grazers, are vulnerable for the dominant winds and form blow outs. If the direction of
the wind is dominant, blow outs can initiate the formation of parabolic dunes, a very
distinct pattern in the landscape. Where parabolic dunes accumulate sediments, the
blowouts may be wind excavated down to the ground water level. Here wet dune
slacks may form of even small lakes which show a remarkable diverse vegetation
(Goudie 2011).
Eventually dune grasslands accumulate organic material in the otherwise rather
sandy soil and wind and sand become a less dominant factor. Encroachment with
larger grasses and forbs as well as the establishment of shrub species lead up to the
dune forests in moderate climates or dense shrublands (e.g. maquis vegetation) in
Mediterranean areas. Also, the wet dune slacks accumulate organic matter and
eventually form an environment where birch forests can develop.
3.7 Inland Saline Habitats
In former times, inland saline habitats were often seen as badlands, and the landscape
scenery was not always perceived as beauty in the eyes of residents. However,
especially during the last decade’s scientific publications have pronounced the
uniqueness of these habitat types (e.g. Evans and Roekarts 2015, factsheets of the
European Environment Agency 2019, and pers. comm. with farmers).
Natural inland saline habitats can occur under arid or semi-arid conditions where
evaporation causes increasing salt concentrations, and in regions where saline or
alkaline waters flow out of the geological surface (salt springs). Such habitats may
also occur where excavation material of mining activities is deposited (Pernik and
292
C. Hobohm et al.