Values
As part of the evaluation of biodiversity, there has been
recognition of the importance of biodiversity in the provision of ecosystem services, processes, and functions. The
importance of saltmarshes for the maintenance of fisheries
has been recognized for more than half a century; other
services, although long recognized anecdotally by local
residents, had only recently been scientifically assessed.
Barbier et al. (2011) have reviewed the services provided
by saltmarsh and attempted an economic evaluation. Economic data are available from a limited number of
saltmarsh types and sites. While the data demonstrate high
values in the instances studied, extrapolation to
saltmarshes as a whole requires caution.
Recent major storms and recognition that the incidents
and intensity of storms are likely to increase in some localities as a result of climate change that has promoted interest in the role of saltmarshes in absorbing wave energy and
protecting the hinterland (Costanza et al., 2008; Koch
et al., 2009). Shepard et al. (2011) have reviewed the role
of saltmarshes in protecting the coastline against storms.
Vegetation cover plays a major role in attenuation of wave
impact, while belowground biomass is important in limiting erosion. Yang et al. (2012) demonstrated that Spartina
alterniflora, an introduced species in China, was more
effective in attenuating wave energy because of its height
than the shorter native species. Whether, given the potentially adverse impacts of S. alterniflora on Chinese
saltmarshes (An et al., 2007), continued planting of
S. alterniflora is justified is a policy question for managers. Tall S. alterniflora is the dominant species in the
Gulf and Atlantic coasts of the United States and may perform a greater role in wave attenuation than the short vegetation of most marshes elsewhere. The magnitude of
attenuation is influenced by storm intensity and water
depth, but it is clear saltmarsh can protect the coastline.
The old concept of “wetlands as wasteland” is dead and
buried. The importance of ecosystem services provided by
wetlands is now firmly established. More intangible, but
no less important, is the aesthetic value of saltmarsh, long
recognized by landscape painters and increasingly so by
a much wider public.
Conservation and management
Saltmarshes have long been valued for conservation.
Some of the earliest formal major conservation reserves
were saltmarshes (Davy, 2009), which have been perceived as valued sites for research and community education and as places of beauty. The large numbers of birds
associated with saltmarshes have also been a major factor
behind the designation of many saltmarsh sites as conservation reserves and the listing of saltmarsh sites as wetlands of international importance under the Ramsar
Convention. Saltmarshes are afforded special protection
in a number of jurisdictions (e.g., in the Australian state
of New South Wales coastal saltmarsh is an Endangered
Ecological Community, while the European Union
Habitats Directive recognizes a range of saltmarshes as
requiring designation as Special Areas of Conservation).
Conservation of saltmarshes will not be achieved simply by designating sites as reserves. Given the range of
threats saltmarshes face, there will need to be active management. Management regimes for saltmarshes need to be
integrated into wider coastal zone management plans
(Shepard et al., 2011), and given the importance of
saltmarshes for migratory birds (and in the case of waterfowl the adverse impacts they may have on saltmarshes),
there needs to be an international component to management plans. Species of fish, for which saltmarsh is nursery
habitat, may distribute widely as adults, so national and
international management of marine resources will also
need to consider saltmarsh. Management of sediment supply and hydrology requires saltmarsh management to be
integrated into catchment management.
Over the past half century, there has been increasing
attention paid to rehabilitation, restoration, and recreation
of saltmarshes (Zedler, 2001; Roman and Burdick, 2012).
Substantial sums have been expended on this work, which
has frequently been mandated by planning and environmental laws. Considerable progress has been made in the
field, but there is still debate as to how success of programs should be measured and whether or not it is
achieved (Ambrose, 2000; Mossman et al. 2012a;
Mossman et al. 2012b).
Summary
Saltmarsh is the natural fringing vegetation of many estuaries, most particularly in temperate and higher latitudes,
but saltmarsh also occurs in conjunction with mangroves
in tropical and subtropical regions. The development of
saltmarsh involves dynamic interactions and feedbacks
between the biota and the physical environment.
Saltmarshes provide habitat for a rich biota. The ecosystem services provided by saltmarshes include sustaining
fisheries, provision of habitat migratory birds, provision
of shoreline protection, and sequestration of carbon.
Anthropogenic pressures on estuarine resources and the
effects of increased carbon dioxide and climate disruption
will pose threats to the long-term sustainability of many
saltmarshes unless coordinated international action can
be undertaken.
Bibliography
Adam, P., 1976. The occurrence of bryophytes on British
saltmarshes. Journal of Bryology, 9, 265–274.
Adam, P., 1978. Geographical variation in British saltmarsh vegetation. Journal of Ecology, 66, 339–366.
Adam, P., 1981. Vegetation of British saltmarshes. New Phytologist,
88, 143–196.
Adam, P., 1990. Saltmarsh Ecology. Cambridge: Cambridge
University Press.
Adam, P., 1997. Absence of creeks and pans in temperate Australian
salt marshes. Mangroves and Salt Marshes, 1, 239–241.
Adam, P., 2000. Morecambe Bay saltmarshes: 25 years of change.
In Sherwood, B. R., Gardiner, B. G., and Harris, T. (eds.), British
Saltmarshes. Tresaith: Forrest Text, pp. 81–107.
530
SALTMARSHES
As part of the evaluation of biodiversity, there has been
recognition of the importance of biodiversity in the provision of ecosystem services, processes, and functions. The
importance of saltmarshes for the maintenance of fisheries
has been recognized for more than half a century; other
services, although long recognized anecdotally by local
residents, had only recently been scientifically assessed.
Barbier et al. (2011) have reviewed the services provided
by saltmarsh and attempted an economic evaluation. Economic data are available from a limited number of
saltmarsh types and sites. While the data demonstrate high
values in the instances studied, extrapolation to
saltmarshes as a whole requires caution.
Recent major storms and recognition that the incidents
and intensity of storms are likely to increase in some localities as a result of climate change that has promoted interest in the role of saltmarshes in absorbing wave energy and
protecting the hinterland (Costanza et al., 2008; Koch
et al., 2009). Shepard et al. (2011) have reviewed the role
of saltmarshes in protecting the coastline against storms.
Vegetation cover plays a major role in attenuation of wave
impact, while belowground biomass is important in limiting erosion. Yang et al. (2012) demonstrated that Spartina
alterniflora, an introduced species in China, was more
effective in attenuating wave energy because of its height
than the shorter native species. Whether, given the potentially adverse impacts of S. alterniflora on Chinese
saltmarshes (An et al., 2007), continued planting of
S. alterniflora is justified is a policy question for managers. Tall S. alterniflora is the dominant species in the
Gulf and Atlantic coasts of the United States and may perform a greater role in wave attenuation than the short vegetation of most marshes elsewhere. The magnitude of
attenuation is influenced by storm intensity and water
depth, but it is clear saltmarsh can protect the coastline.
The old concept of “wetlands as wasteland” is dead and
buried. The importance of ecosystem services provided by
wetlands is now firmly established. More intangible, but
no less important, is the aesthetic value of saltmarsh, long
recognized by landscape painters and increasingly so by
a much wider public.
Conservation and management
Saltmarshes have long been valued for conservation.
Some of the earliest formal major conservation reserves
were saltmarshes (Davy, 2009), which have been perceived as valued sites for research and community education and as places of beauty. The large numbers of birds
associated with saltmarshes have also been a major factor
behind the designation of many saltmarsh sites as conservation reserves and the listing of saltmarsh sites as wetlands of international importance under the Ramsar
Convention. Saltmarshes are afforded special protection
in a number of jurisdictions (e.g., in the Australian state
of New South Wales coastal saltmarsh is an Endangered
Ecological Community, while the European Union
Habitats Directive recognizes a range of saltmarshes as
requiring designation as Special Areas of Conservation).
Conservation of saltmarshes will not be achieved simply by designating sites as reserves. Given the range of
threats saltmarshes face, there will need to be active management. Management regimes for saltmarshes need to be
integrated into wider coastal zone management plans
(Shepard et al., 2011), and given the importance of
saltmarshes for migratory birds (and in the case of waterfowl the adverse impacts they may have on saltmarshes),
there needs to be an international component to management plans. Species of fish, for which saltmarsh is nursery
habitat, may distribute widely as adults, so national and
international management of marine resources will also
need to consider saltmarsh. Management of sediment supply and hydrology requires saltmarsh management to be
integrated into catchment management.
Over the past half century, there has been increasing
attention paid to rehabilitation, restoration, and recreation
of saltmarshes (Zedler, 2001; Roman and Burdick, 2012).
Substantial sums have been expended on this work, which
has frequently been mandated by planning and environmental laws. Considerable progress has been made in the
field, but there is still debate as to how success of programs should be measured and whether or not it is
achieved (Ambrose, 2000; Mossman et al. 2012a;
Mossman et al. 2012b).
Summary
Saltmarsh is the natural fringing vegetation of many estuaries, most particularly in temperate and higher latitudes,
but saltmarsh also occurs in conjunction with mangroves
in tropical and subtropical regions. The development of
saltmarsh involves dynamic interactions and feedbacks
between the biota and the physical environment.
Saltmarshes provide habitat for a rich biota. The ecosystem services provided by saltmarshes include sustaining
fisheries, provision of habitat migratory birds, provision
of shoreline protection, and sequestration of carbon.
Anthropogenic pressures on estuarine resources and the
effects of increased carbon dioxide and climate disruption
will pose threats to the long-term sustainability of many
saltmarshes unless coordinated international action can
be undertaken.
Bibliography
Adam, P., 1976. The occurrence of bryophytes on British
saltmarshes. Journal of Bryology, 9, 265–274.
Adam, P., 1978. Geographical variation in British saltmarsh vegetation. Journal of Ecology, 66, 339–366.
Adam, P., 1981. Vegetation of British saltmarshes. New Phytologist,
88, 143–196.
Adam, P., 1990. Saltmarsh Ecology. Cambridge: Cambridge
University Press.
Adam, P., 1997. Absence of creeks and pans in temperate Australian
salt marshes. Mangroves and Salt Marshes, 1, 239–241.
Adam, P., 2000. Morecambe Bay saltmarshes: 25 years of change.
In Sherwood, B. R., Gardiner, B. G., and Harris, T. (eds.), British
Saltmarshes. Tresaith: Forrest Text, pp. 81–107.
530
SALTMARSHES