20.2.2 Restoring Dunefields: Vegetation vs Sand
Dunefields are very diverse and range from foredune plains, foredune–blowout
complexes, parabolic dunefields to transgressive dune sheets and dunefields (Hesp
2004; Hesp and walker 2012; Hesp et al. 2011)
Restoration of dunefields can be very generally grouped into two contrasting
sets of actions: the reactivation of stabilized dunes and the stabilization of mobile
dunes. Usually, the goal is to restore the heterogeneity of features in the geotemporal context (Psuty and Silveira, Chap. 3, this volume; Hesp and Hilton,
Chap. 5, this volume; Arens et al. 2004), and improve/change the environment for
psammophyte species including plants and animals (Pickart, Chap. 10, this volume; van der Hagen et al. 2008). Needless to say, human needs are also a common
reason for restoration.
Drivers influencing dune stabilization can be direct and human-induced (e.g.,
removal and/or flattening of dunes; stabilization by urban, industrial and farming
infrastructure; plantations of grasses, herbs, shrubs or trees; introduction or
removal of grazing, off-road vehicle activity, nutrient enrichment due to pollution);
indirect and external (e.g., changes in sediment supply, salt spray, and water
availability and water table heights, nutrient enrichment, and climate change); and
internal (such as soil development, and grazing) (Rhind et al., Chap. 8, this volume; Arens and Geelen 2006).
From perhaps the earliest historic times humans have destroyed, modified or
changed dune systems, both continental and coastal, often because of farming
activities and forest felling. The creation of drifting sands was enhanced in some
cases by climatic events (e.g., the Little Ice Age in Europe). Humans then tended
to view all drifting sands as bad and attempted to stabilize them, often with
considerable success, but commonly by introducing exotic species and creating
mono-specific stands (Muñoz-Reinoso et al., Chap. 9, this volume; Arens et al.,
Chap. 7, this volume; Moreno-Casasola et al., Chap. 14, this volume; Pickart,
Chap. 10, this volume; Grootjans et al. 2001; van der Meulen and Salman 1996;
Bossuyt et al. 2007). This trend continued into the late 1900 s in some countries,
and, led by agriculturalists and soil conservationists in particular, many exotic
species were introduced into coastal dunes, and then spread from those sites,
becoming invasive species.
Stabilization (both natural and artificially induced) of the natural dunes results
in the loss of space or habitat for the native species (Hesp and Hilton, Chap. 5, this
volume; Pickart, Chap. 10, this volume); the rare and uncommon obligate or semiobligate psammophytes (Rhind et al., Chap. 8, this volume); the dune slack hygrophytes (Grootjans et al., Chap. 15, this volume); as well as many other impacts.
When dunes become stabilized, diversity decreases because the early successional
stages disappear, and certain landform units may not be formed (e.g., deflation
basins and plains, wet slacks, gegenwalle ridges, precipitation, and trailing ridges,
etc.) resulting in habitat and diversity losses or changes (Arens and Geelen 2006;
Arens et al., Chap. 7, this volume; Rhind and Jones 2010; Rhind et al., Chap. 8,
20 Coastal Dune Restoration: Trends and Perspectives
329
Dunefields are very diverse and range from foredune plains, foredune–blowout
complexes, parabolic dunefields to transgressive dune sheets and dunefields (Hesp
2004; Hesp and walker 2012; Hesp et al. 2011)
Restoration of dunefields can be very generally grouped into two contrasting
sets of actions: the reactivation of stabilized dunes and the stabilization of mobile
dunes. Usually, the goal is to restore the heterogeneity of features in the geotemporal context (Psuty and Silveira, Chap. 3, this volume; Hesp and Hilton,
Chap. 5, this volume; Arens et al. 2004), and improve/change the environment for
psammophyte species including plants and animals (Pickart, Chap. 10, this volume; van der Hagen et al. 2008). Needless to say, human needs are also a common
reason for restoration.
Drivers influencing dune stabilization can be direct and human-induced (e.g.,
removal and/or flattening of dunes; stabilization by urban, industrial and farming
infrastructure; plantations of grasses, herbs, shrubs or trees; introduction or
removal of grazing, off-road vehicle activity, nutrient enrichment due to pollution);
indirect and external (e.g., changes in sediment supply, salt spray, and water
availability and water table heights, nutrient enrichment, and climate change); and
internal (such as soil development, and grazing) (Rhind et al., Chap. 8, this volume; Arens and Geelen 2006).
From perhaps the earliest historic times humans have destroyed, modified or
changed dune systems, both continental and coastal, often because of farming
activities and forest felling. The creation of drifting sands was enhanced in some
cases by climatic events (e.g., the Little Ice Age in Europe). Humans then tended
to view all drifting sands as bad and attempted to stabilize them, often with
considerable success, but commonly by introducing exotic species and creating
mono-specific stands (Muñoz-Reinoso et al., Chap. 9, this volume; Arens et al.,
Chap. 7, this volume; Moreno-Casasola et al., Chap. 14, this volume; Pickart,
Chap. 10, this volume; Grootjans et al. 2001; van der Meulen and Salman 1996;
Bossuyt et al. 2007). This trend continued into the late 1900 s in some countries,
and, led by agriculturalists and soil conservationists in particular, many exotic
species were introduced into coastal dunes, and then spread from those sites,
becoming invasive species.
Stabilization (both natural and artificially induced) of the natural dunes results
in the loss of space or habitat for the native species (Hesp and Hilton, Chap. 5, this
volume; Pickart, Chap. 10, this volume); the rare and uncommon obligate or semiobligate psammophytes (Rhind et al., Chap. 8, this volume); the dune slack hygrophytes (Grootjans et al., Chap. 15, this volume); as well as many other impacts.
When dunes become stabilized, diversity decreases because the early successional
stages disappear, and certain landform units may not be formed (e.g., deflation
basins and plains, wet slacks, gegenwalle ridges, precipitation, and trailing ridges,
etc.) resulting in habitat and diversity losses or changes (Arens and Geelen 2006;
Arens et al., Chap. 7, this volume; Rhind and Jones 2010; Rhind et al., Chap. 8,
20 Coastal Dune Restoration: Trends and Perspectives
329