Definition
Wetlands are seasonal or permanent freshwater- or
saltwater-saturated dynamic ecosystems. Reclamation
restores degraded wetlands to their former hydrological
and ecological functions. Wetland reclamation is the rehabilitation of degraded wetlands habitat, reconstructing the
impacted habitat as closely as possible to its original condition with respect to hydrological, ecological (vegetation,
habitats), and morphological (soil) components.
Description
Wetlands are altered by the removal of stream bank vegetation, dredging and dredge-spoil disposal, ditching, intrusion of invasive species, and other factors. Wetland
reclamation initially involves the stabilization of the
degraded area, characterizing soil and water quality, and
defining the inherent ecological features of the habitat.
Wetland reclamation activities require multidisciplinary expertise, including hydrologists, ecologists,
geologists, engineers, etc. A successful wetland reclamation project must define how wetlands work, if the wetlands can be restored and created, and the best
approaches to restore and create the wetlands (Mitsch,
2005). Elements common to wetland reclamation projects
are site-selection criteria, hydrologic analysis, water
source and quality, substrate augmentation and handling,
plant material selection and handling, buffer zone placement, and long-term management (Kentula, 2002).
Estuarine wetlands are strongly influenced by tides;
therefore, the dominant water source is tidal fresh or
brackish water controlled by tidal action. In estuarine wetlands reclamation, restoration can be effectively accomplished by blocking channels which allow tidal saltwater
inundation (USDA, 2008).
Similar to other reclamation projects in estuarine
systems, wetlands reclamation in the early planning
stage considers financial, social, and scientific feasibility
studies that must be completed to determine whether the
proposed reclamation activity is sustainable. The proposed
goals must be monitored before, during, and after the reclamation project. Adaptive management is defined as the
additional actions or adjustments that may be needed during the post-project monitoring process (USEPA, 2000).
Restoring lost or degraded wetlands is a valuable and
cost-effective way for society to enhance wetlands ecosystem services. This includes reducing the risk to humans of
impacts from coastal storms and other extreme events,
improving food and water security, and increasing the
capacity to mitigate and adapt to climate change
(Alexander and McInnes, 2012).
Bibliography
Alexander, S., and McInnes, R. 2012. The benefits of Wetland restoration. In Ramsar Scientific and Technical Briefing Note
No. 4. Gland: Ramsar Convention Secretariat.
Kentula, M. E., 2002. Wetland Restoration and Creation, National
Water Summary on Wetland Resources. United States Geological
Survey Water Supply Paper 2425. Washington, DC:U.S.
Geological Survey.
Mitsch, W. J., 2005. Wetland creation, restoration, and conservation: a wetland invitational at the Olentangy River Wetland
Research Park. Ecological Engineering, 24, 243–251.
United States Department of Agriculture (USDA) Natural
Resources Conservation Service, 2008. Wetland Restoration,
Enhancement, or Creation. Engineering Field Handbook.
Chapter 13. Washington, DC: US Department of Agriculture.
USEPA, 2000. Principles for the Ecological Restoration of Aquatic
Resources. EPA841-F-00-003. Office of Water (4501F).
Washington, DC: U.S. Environmental Protection Agency.
Cross-references
Coastal Wetlands
Marsh Drowning
Wetlands
WRACK
Keryn Gedan
Department of Biology, University of Maryland,
College Park, MD, USA
Definition
The accumulation of dead plant matter in marine systems.
Description
In some productive marine ecosystems, plant matter accumulates at a faster rate than it can decompose. Dead plant
material floats and aggregates at the landward margin of
a marsh or beach or against any other barriers that hinder
movement on the tide. At the high water mark, or strandline, wrack can form a mat centimeters thick that can block
light and retain moisture. In temperate coastal wetlands,
wrack mat formation has a seasonal cycle; the aboveground portion of plants senesces in the winter, leaving
brittle, dry stems, which are easily broken by the elements
and which form into wrack mats on the high tides in spring
(Valiela and Rietsma, 1995). Seagrass, kelp, and
macroalgae beds also produce wrack. Wrack mats are
a disturbance that can kill underlying plants creating bare
space in vegetated habitats (Bertness and Ellison, 1987).
Where stressful edaphic conditions are exacerbated by
the loss of the plant canopy, as in salt marshes, bare spots
formed by wrack mats can be persistent and are colonized
by stress-tolerant fugitive species (Bertness, 1991). However, some animals seek refuge in the cooler and moister
microclimate of wrack mats, and wrack is an important
food resource for detritivores, particularly in low productivity systems like beaches (Dugan et al., 2003).
Bibliography
Bertness, M. D., 1991. Interspecific interactions among high marsh
perennials in a New England salt marsh. Ecology, 72, 125–137.
Bertness, M. D., and Ellison, A. M., 1987. Determinants of pattern
in a New England salt marsh plant community. Ecological
Monographs, 57, 129–147.
742
WRACK
Wetlands are seasonal or permanent freshwater- or
saltwater-saturated dynamic ecosystems. Reclamation
restores degraded wetlands to their former hydrological
and ecological functions. Wetland reclamation is the rehabilitation of degraded wetlands habitat, reconstructing the
impacted habitat as closely as possible to its original condition with respect to hydrological, ecological (vegetation,
habitats), and morphological (soil) components.
Description
Wetlands are altered by the removal of stream bank vegetation, dredging and dredge-spoil disposal, ditching, intrusion of invasive species, and other factors. Wetland
reclamation initially involves the stabilization of the
degraded area, characterizing soil and water quality, and
defining the inherent ecological features of the habitat.
Wetland reclamation activities require multidisciplinary expertise, including hydrologists, ecologists,
geologists, engineers, etc. A successful wetland reclamation project must define how wetlands work, if the wetlands can be restored and created, and the best
approaches to restore and create the wetlands (Mitsch,
2005). Elements common to wetland reclamation projects
are site-selection criteria, hydrologic analysis, water
source and quality, substrate augmentation and handling,
plant material selection and handling, buffer zone placement, and long-term management (Kentula, 2002).
Estuarine wetlands are strongly influenced by tides;
therefore, the dominant water source is tidal fresh or
brackish water controlled by tidal action. In estuarine wetlands reclamation, restoration can be effectively accomplished by blocking channels which allow tidal saltwater
inundation (USDA, 2008).
Similar to other reclamation projects in estuarine
systems, wetlands reclamation in the early planning
stage considers financial, social, and scientific feasibility
studies that must be completed to determine whether the
proposed reclamation activity is sustainable. The proposed
goals must be monitored before, during, and after the reclamation project. Adaptive management is defined as the
additional actions or adjustments that may be needed during the post-project monitoring process (USEPA, 2000).
Restoring lost or degraded wetlands is a valuable and
cost-effective way for society to enhance wetlands ecosystem services. This includes reducing the risk to humans of
impacts from coastal storms and other extreme events,
improving food and water security, and increasing the
capacity to mitigate and adapt to climate change
(Alexander and McInnes, 2012).
Bibliography
Alexander, S., and McInnes, R. 2012. The benefits of Wetland restoration. In Ramsar Scientific and Technical Briefing Note
No. 4. Gland: Ramsar Convention Secretariat.
Kentula, M. E., 2002. Wetland Restoration and Creation, National
Water Summary on Wetland Resources. United States Geological
Survey Water Supply Paper 2425. Washington, DC:U.S.
Geological Survey.
Mitsch, W. J., 2005. Wetland creation, restoration, and conservation: a wetland invitational at the Olentangy River Wetland
Research Park. Ecological Engineering, 24, 243–251.
United States Department of Agriculture (USDA) Natural
Resources Conservation Service, 2008. Wetland Restoration,
Enhancement, or Creation. Engineering Field Handbook.
Chapter 13. Washington, DC: US Department of Agriculture.
USEPA, 2000. Principles for the Ecological Restoration of Aquatic
Resources. EPA841-F-00-003. Office of Water (4501F).
Washington, DC: U.S. Environmental Protection Agency.
Cross-references
Coastal Wetlands
Marsh Drowning
Wetlands
WRACK
Keryn Gedan
Department of Biology, University of Maryland,
College Park, MD, USA
Definition
The accumulation of dead plant matter in marine systems.
Description
In some productive marine ecosystems, plant matter accumulates at a faster rate than it can decompose. Dead plant
material floats and aggregates at the landward margin of
a marsh or beach or against any other barriers that hinder
movement on the tide. At the high water mark, or strandline, wrack can form a mat centimeters thick that can block
light and retain moisture. In temperate coastal wetlands,
wrack mat formation has a seasonal cycle; the aboveground portion of plants senesces in the winter, leaving
brittle, dry stems, which are easily broken by the elements
and which form into wrack mats on the high tides in spring
(Valiela and Rietsma, 1995). Seagrass, kelp, and
macroalgae beds also produce wrack. Wrack mats are
a disturbance that can kill underlying plants creating bare
space in vegetated habitats (Bertness and Ellison, 1987).
Where stressful edaphic conditions are exacerbated by
the loss of the plant canopy, as in salt marshes, bare spots
formed by wrack mats can be persistent and are colonized
by stress-tolerant fugitive species (Bertness, 1991). However, some animals seek refuge in the cooler and moister
microclimate of wrack mats, and wrack is an important
food resource for detritivores, particularly in low productivity systems like beaches (Dugan et al., 2003).
Bibliography
Bertness, M. D., 1991. Interspecific interactions among high marsh
perennials in a New England salt marsh. Ecology, 72, 125–137.
Bertness, M. D., and Ellison, A. M., 1987. Determinants of pattern
in a New England salt marsh plant community. Ecological
Monographs, 57, 129–147.
742
WRACK