2.2.4 Using Vegetation
Vegetation reduces wind speed, traps sand, stabilizes surface sediment, provides
habitat, and improves aesthetic appeal (Schwendiman 1977; Hesp 1989; Mitteager
et al. 2006; Nordstrom 2008). The characteristics of the vegetation have important
implications for the goods and services provided by coastal dunes. Basic dunestabilizing vegetation for use by municipal managers and residents should consist of
native species that are easy to propagate, harvest, store, and transplant with a high
survival rate, be commercially available at local nurseries at a relatively low cost,
and be able to grow in a variety of microhabitats on a spatially restricted foredune
(Feagin 2005; Mitteager et al. 2006). The species that are most useful in building
foredunes rapidly react positively to sand burial (Maun 1998). When sand deposition
diminishes, initial dune-building species can degenerate, but successional species
can be planted where sand deposition cannot be reinitiated (van der Putten and Peters
1995). Degeneration of Ammophila (arenaria or breviligulata, whichever is native),
for example, is not a problem where the loss is coincident with colonization by later
successional species (Vestergaard and Hansen 1992).
Other species may be more suitable for planting in environments landward of the
active foredune crest, e.g., Spartina patens in dune swales, but the use of other
species may not be necessary because they will eventually opportunistically colonize
the dune themselves (Feagin 2005). Stabilizing the sand surface with one species can
ameliorate environmental extremes and facilitate the establishment of other species
that are less adapted to stressful environments (Martínez and Garcia-Franco 2004;
De Lillis et al. 2004). Endangered species can colonize restored areas if populations
and seed sources are present nearby and if dispersal mechanisms (wind, water or
animals) are effective (Avis 1995; Snyder and Boss 2002; Grootjans 2004), although
sometimes endangered species need some assistance to colonize.
2.3 Retaining an Element of Natural Dynamism
Natural foredunes are inherently dynamic and fragmented, with portions in an
incipient state and portions at a more developed stage (Ritchie and Penland 1990;
Doody 2001). Some degree of natural dynamism is important to allow landforms
to be diverse and self-sustaining (Nordstrom 2008). Tolerance to burial is an
important cause of zonation of plant species on coastal foredunes, and burial can
have a stimulating, positive effect on the growth of dune-building plants and
prevent degeneration (Maun 2004). Many plant species can occur in sand dunes,
but the species most dependent on dune habitat tend to be concentrated in zones
with greater sand movement (Castillo and Moreno-Casasola 1996; Rhind and
Jones 1999). The variety of local topographic relief and small-scale differences in
sheltering and proximity to the water table enhance the variety of habitats across
and along the shore, and the resulting ecosystem services they provide (Everard
et al. 2010).
2 Foredune Restoration
23
Vegetation reduces wind speed, traps sand, stabilizes surface sediment, provides
habitat, and improves aesthetic appeal (Schwendiman 1977; Hesp 1989; Mitteager
et al. 2006; Nordstrom 2008). The characteristics of the vegetation have important
implications for the goods and services provided by coastal dunes. Basic dunestabilizing vegetation for use by municipal managers and residents should consist of
native species that are easy to propagate, harvest, store, and transplant with a high
survival rate, be commercially available at local nurseries at a relatively low cost,
and be able to grow in a variety of microhabitats on a spatially restricted foredune
(Feagin 2005; Mitteager et al. 2006). The species that are most useful in building
foredunes rapidly react positively to sand burial (Maun 1998). When sand deposition
diminishes, initial dune-building species can degenerate, but successional species
can be planted where sand deposition cannot be reinitiated (van der Putten and Peters
1995). Degeneration of Ammophila (arenaria or breviligulata, whichever is native),
for example, is not a problem where the loss is coincident with colonization by later
successional species (Vestergaard and Hansen 1992).
Other species may be more suitable for planting in environments landward of the
active foredune crest, e.g., Spartina patens in dune swales, but the use of other
species may not be necessary because they will eventually opportunistically colonize
the dune themselves (Feagin 2005). Stabilizing the sand surface with one species can
ameliorate environmental extremes and facilitate the establishment of other species
that are less adapted to stressful environments (Martínez and Garcia-Franco 2004;
De Lillis et al. 2004). Endangered species can colonize restored areas if populations
and seed sources are present nearby and if dispersal mechanisms (wind, water or
animals) are effective (Avis 1995; Snyder and Boss 2002; Grootjans 2004), although
sometimes endangered species need some assistance to colonize.
2.3 Retaining an Element of Natural Dynamism
Natural foredunes are inherently dynamic and fragmented, with portions in an
incipient state and portions at a more developed stage (Ritchie and Penland 1990;
Doody 2001). Some degree of natural dynamism is important to allow landforms
to be diverse and self-sustaining (Nordstrom 2008). Tolerance to burial is an
important cause of zonation of plant species on coastal foredunes, and burial can
have a stimulating, positive effect on the growth of dune-building plants and
prevent degeneration (Maun 2004). Many plant species can occur in sand dunes,
but the species most dependent on dune habitat tend to be concentrated in zones
with greater sand movement (Castillo and Moreno-Casasola 1996; Rhind and
Jones 1999). The variety of local topographic relief and small-scale differences in
sheltering and proximity to the water table enhance the variety of habitats across
and along the shore, and the resulting ecosystem services they provide (Everard
et al. 2010).
2 Foredune Restoration
23