376
Kenneth A. Moore and Frederick T. Short
demonstrated in Z. capricorni (Haynes et al., 2000;
Macinnis-Ng et al., 2002, 2003) and Z. marina
(Ralph and Short, 2002). The advantages of PAM
techniques are their ability to detect photosystem
characteristics non-invasively (Larkum et al., Chapter 14). PAM techniques are potentially very useful in
providing rapid assessment of the quality and health
of Zostera systems for management purposes. However their application in the field still requires a great
deal of development and testing.
C. Monitoring
Zostera distribution and health has been monitored
through both aerial and ground assessments more
than any other genus as a result of the ongoing
and long-standing focus on Z. marina in Europe
(Bostr¨ om et al., 2003; Hily et al., 2003), North America (Koch and Orth, 2003; Short and Short, 2003;
Wyllie-Echeverria and Ackerman, 2003) and Asia
(Aioi and Nakaoka, 2003; Lee and Lee, 2003). Until
recently, only localized monitoring, often with varying methodology, has been done. Little to no longterm monitoring has been done on the other eight
Zostera species. Global monitoring of seagrasses has
begun (www.SeagrassNet.org), but for Zostera these
efforts are still limited. Repeated monitoring yields
knowledge on the time course of change in seagrass
habitat (Moore et al., 2000; Burdick and Kendrick,
2001) and could provide comparative information on
Zostera species from around the world. In order to
assess the magnitude of anthropogenic impacts and
distinguish the signature of global climate change
(Short and Neckles, 1999), long-term, comparable
monitoring efforts are critical.
D. Restoration
The environmental factor with the greatest impact to
seagrass habitats worldwide is the reduction in water clarity that results from anthropogenic inputs to
coastal waters (Short and Wyllie-Echeverria, 1996).
Improvement of water clarity is the single greatest factor that will aid in the restoration of Zostera
species. Obviously, reduced anthropogenic inputs
through reduction in nutrient loading and elimination of sediment discharge into coastal waters will
result in improved water clarity. Such improvements
in water clarity will allow Zostera to begin to reestablish its former distribution and achieve historical
depth limits. The current trends in human population growth and distribution make achievement of
these goals an extreme and costly challenge requiring major financial input, political will, and environmental awareness. Locally, reduction in nutrients and
sediments that enter into the system and increased
flushing in restricted lagoons and harbors can improve water clarity. Unfortunately, cleanup efforts
will require long-term commitments because of cost
and because changes to land use practices take time
to implement and ground water residence time in
coastal systems can be decades or longer (Phillips
et al., 1999; Robinson and Reay, 2002).
Since Zostera species and other seagrasses have
the capacity to improve water clarity in their local
environment by promoting particle settlement, reducing re-suspension and taking up nutrients (Kemp
et al., 1984; Ward et al., 1984; Fonseca, 1996; Koch,
1999b), once plants are lost from a system, water
quality requirements for recovery may actually be
greater that those needed for maintenance of existing
populations (Kemp et al., 2004). Similarly, propagule supply of both vegetative material and seeds in
established beds may provide a greater capacity for
recovery from episodic stresses (Orth and Moore,
1986; Guerrini et al., 1999) than areas with no established plants that have to rely on seeds or propagules from other areas (Orth et al., 1994; Harwell and
Orth, 2001, 2002, Orth et al., Chapter 5).
Most seagrass restoration has occurred in Z. marina habitat and has progressed from early transplant efforts (Phillips, 1974; Fonseca et al., 1982)
to more scientific investigations of site selection
and transplant methodologies (Fonseca et al., 1998;
Calumpong and Fonseca, 2001; Short et al., 2002a).
Zostera restoration-science efforts now include rigorous methodology for fulfilling the statutory requirements for compensatory mitigation to offset
impacts to the seagrass (Davis and Short, 1997;
Fonseca et al., 1998) and simplifying the techniques, reducing the costs, and developing procedures that community-based volunteer groups can
use to embrace the task of revitalizing the coastal
environment (Short et al., 2002b). Both mitigation
and community-based restoration are important and
needed to slow the loss of seagrass habitat and reverse the trend of coastal ecosystem degradation.
Much of the information in restoration science has
come from work on Z . marina (Table 3).
The scientific tools for Zostera are: (a) a quantitative site selection model (Short et al., 2002a);
(b) a protocol to identify a sustainable source
Kenneth A. Moore and Frederick T. Short
demonstrated in Z. capricorni (Haynes et al., 2000;
Macinnis-Ng et al., 2002, 2003) and Z. marina
(Ralph and Short, 2002). The advantages of PAM
techniques are their ability to detect photosystem
characteristics non-invasively (Larkum et al., Chapter 14). PAM techniques are potentially very useful in
providing rapid assessment of the quality and health
of Zostera systems for management purposes. However their application in the field still requires a great
deal of development and testing.
C. Monitoring
Zostera distribution and health has been monitored
through both aerial and ground assessments more
than any other genus as a result of the ongoing
and long-standing focus on Z. marina in Europe
(Bostr¨ om et al., 2003; Hily et al., 2003), North America (Koch and Orth, 2003; Short and Short, 2003;
Wyllie-Echeverria and Ackerman, 2003) and Asia
(Aioi and Nakaoka, 2003; Lee and Lee, 2003). Until
recently, only localized monitoring, often with varying methodology, has been done. Little to no longterm monitoring has been done on the other eight
Zostera species. Global monitoring of seagrasses has
begun (www.SeagrassNet.org), but for Zostera these
efforts are still limited. Repeated monitoring yields
knowledge on the time course of change in seagrass
habitat (Moore et al., 2000; Burdick and Kendrick,
2001) and could provide comparative information on
Zostera species from around the world. In order to
assess the magnitude of anthropogenic impacts and
distinguish the signature of global climate change
(Short and Neckles, 1999), long-term, comparable
monitoring efforts are critical.
D. Restoration
The environmental factor with the greatest impact to
seagrass habitats worldwide is the reduction in water clarity that results from anthropogenic inputs to
coastal waters (Short and Wyllie-Echeverria, 1996).
Improvement of water clarity is the single greatest factor that will aid in the restoration of Zostera
species. Obviously, reduced anthropogenic inputs
through reduction in nutrient loading and elimination of sediment discharge into coastal waters will
result in improved water clarity. Such improvements
in water clarity will allow Zostera to begin to reestablish its former distribution and achieve historical
depth limits. The current trends in human population growth and distribution make achievement of
these goals an extreme and costly challenge requiring major financial input, political will, and environmental awareness. Locally, reduction in nutrients and
sediments that enter into the system and increased
flushing in restricted lagoons and harbors can improve water clarity. Unfortunately, cleanup efforts
will require long-term commitments because of cost
and because changes to land use practices take time
to implement and ground water residence time in
coastal systems can be decades or longer (Phillips
et al., 1999; Robinson and Reay, 2002).
Since Zostera species and other seagrasses have
the capacity to improve water clarity in their local
environment by promoting particle settlement, reducing re-suspension and taking up nutrients (Kemp
et al., 1984; Ward et al., 1984; Fonseca, 1996; Koch,
1999b), once plants are lost from a system, water
quality requirements for recovery may actually be
greater that those needed for maintenance of existing
populations (Kemp et al., 2004). Similarly, propagule supply of both vegetative material and seeds in
established beds may provide a greater capacity for
recovery from episodic stresses (Orth and Moore,
1986; Guerrini et al., 1999) than areas with no established plants that have to rely on seeds or propagules from other areas (Orth et al., 1994; Harwell and
Orth, 2001, 2002, Orth et al., Chapter 5).
Most seagrass restoration has occurred in Z. marina habitat and has progressed from early transplant efforts (Phillips, 1974; Fonseca et al., 1982)
to more scientific investigations of site selection
and transplant methodologies (Fonseca et al., 1998;
Calumpong and Fonseca, 2001; Short et al., 2002a).
Zostera restoration-science efforts now include rigorous methodology for fulfilling the statutory requirements for compensatory mitigation to offset
impacts to the seagrass (Davis and Short, 1997;
Fonseca et al., 1998) and simplifying the techniques, reducing the costs, and developing procedures that community-based volunteer groups can
use to embrace the task of revitalizing the coastal
environment (Short et al., 2002b). Both mitigation
and community-based restoration are important and
needed to slow the loss of seagrass habitat and reverse the trend of coastal ecosystem degradation.
Much of the information in restoration science has
come from work on Z . marina (Table 3).
The scientific tools for Zostera are: (a) a quantitative site selection model (Short et al., 2002a);
(b) a protocol to identify a sustainable source