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Eelgrass mapping to inform land use and conservation

Eelgrass is seen as a critical nearshore habitat for birds, mammals, invertebrates and fish.

Eelgrass is seen as a critical nearshore habitat for birds, mammals, invertebrates and fish. Eelgrass beds are also an important carbon sink, according to a communication from the Islands Trust to the Bowen Island Municipality that announced the Trust's plan to map eelgrass on Bowen Island.

Councillor and Islands Trust trustee Andrew Stone welcomes the initiative.

"Several years ago, the Islands Trust started eelgrass and foreshore mapping of all the islands," Stone said at the July 22 council meeting. "Then there was a decision made that the funding was going to come from local governments and only the mapping of the unincorporated islands was done."

Stone said he took part in presentations and workshops and advocated for Bowen Island to be included in the study.

This summer, the Islands Trust and Islands Trust Fund are partnering with the SeaChange Marine Conservation Society to complete eelgrass inventories for the area of the Islands Trust.

"The goal of these surveys is to identify the presence and absence of eelgrass habitats that surround all 13 islands so that communities can protect and manage these critical fish and bird habitats," Nikki Wright, executive director of SeaChange explained.

Wright said that the eelgrass inventory is taken by boat and with an underwater camera. "The subtidal and intertidal edges are determined with a Trimble GPS unit in order that a polygon can be drawn of the eelgrass habitat. Characteristics of the eelgrass present are noted, such as substrate type, depth, whether the plants are growing within a narrow fringing bed or flat meadow, and whether they are patchy or continuous. Other notes are taken about nearshore and backshore characteristics as well, whether they are in a natural state or developed," Wright said. She added that while the presence of marine life such as marine mammals, birds and underwater life is noted, the priority of the study is to determine the extent of eelgrass off the shores of Bowen Island. This year's findings will be compared to the inventories done in the past, says Wright, and the maps produced from this field survey will be posted on the Islands Trust Fund website in early 2014 (the 2012 maps can be found at http://www.islandstrustfund.bc.ca/initiatives/marineconservation/eelgrass-mappinq.aspx).

In order to look at comparisons, the Islands Trust has asked SeaChange to gather information from local conservancies and known marine stewardship groups.

"Bowen Island eelgrass mapping will be slightly different from mapping for the other islands. It will be polygon-based and will map the full extent of the eelgrass beds. The additional cost of the polygon mapping has been funded by Metro Vancouver," the Islands Trust statement explains. "Eelgrass mapping is intended to provide support for BIM, local trust committees and the Trust Fund board in making science-based decisions about land use and conservation that preserve foreshore ecosystems in the Islands Trust area. Eelgrass mapping will serve as a baseline inventory to monitor the effects of conservation activities, such as Marine Protected Areas, as well as human impacts, such as potential increased tanker traffic, marine industrial activities (e.g. log dumping and booms) and foreshore use (e.g. wharves and docks). It will also enable marine conservation groups to identify areas ideal for eelgrass restoration."

Councillor Cro Lucas said that eelgrass habitats can potentially inform the municipality's policy for the construction of new docks and wharves. Stone added that this was one of the reasons he got actively involved. "This will give us the science to identify eco-sensitive areas," he said.

Wright said that SeaChange is part of a network of coastal stewardship groups, the Seagrass Conservation Working Group, that was formed in 2001 as a partnership of local, provincial and federal governments, First Nations, scientists and conservation groups. "Native eelgrass has been our focus thus far. Bowen Island has been a part of this network, and has done eelgrass mapping in the past. The hope is that many more communities will become engaged in protecting these valuable nearshore underwater meadows through inventories, educational programs and events as those places where eelgrass meadows have diminished or disappeared, the number of fish species and marine diversity drops," she said.

SeaChange plans to map Bowen Island from August 7 to 10, depending on prevailing winds.

"The subtidal and intertidal edges are determined with a Trimble GPS unit in order that a polygon can be drawn of the eelgrass habitat. Characteristics of the eelgrass present are noted, such as substrate type, depth, whether the plants are growing within a narrow fringing bed or flat meadow, and whether they are patchy or continuous. Other notes are taken about nearshore and backshore characteristics as well, whether they are in a natural state or developed," Wright said. She added that while the presence of marine life such as marine mammals, birds and underwater life is noted, the priority of the study is to determine the extent of eelgrass off the shores of Bowen Island. This year's findings will be compared to the inventories done in the past, says Wright, and the maps produced from the field survey will be posted on the Islands Trust Fund website in early 2014 (the 2012 maps can be found at http://www.islandstrustfund.bc.ca/initiatives/marineconservation/eelgrass-mappinq.aspx).In order to look at comparisons, the Islands Trust has asked SeaChange to gather information from local conservancies and known marine stewardship groups.

"Bowen Island eelgrass mapping will be slightly different from mapping for the other islands. It will be polygon-based and will map the full extent of the eelgrass beds. The additional cost of the polygon mapping has been funded by Metro Vancouver," the Islands Trust statement explains. "Eelgrass mapping is intended to provide support for BIM, local trust committees and the Trust Fund board in making science-based decisions about land use and conservation that preserve foreshore ecosystems in the Islands Trust area. Eelgrass mapping will serve as a baseline inventory to monitor the effects of conservation activities, such as Marine Protected Areas, as well as human impacts, such as potential increased tanker traffic, marine industrial activities (e.g. log dumping and booms) and foreshore use (e.g. wharves and docks). It will also enable marine conservation groups to identify areas ideal for eelgrass restoration."

Councillor Cro Lucas said that eelgrass habitats can potentially inform the municipality's policy for the construction of new docks and wharves. Stone added that this was one of the reasons he got actively involved. "This will give us the science to identify eco-sensitive areas," he said.

Wright said that SeaChange is part of a network of coastal stewardship groups, the Seagrass Conservation Working Group, that was formed in 2001 as a partnership of local, provincial and federal governments, First Nations, scientists and conservation groups. "Native eelgrass has been our focus thus far. Bowen Island has been a part of this network, and has done eelgrass mapping in the past. The hope is that many more communities will become engaged in protecting these valuable nearshore underwater meadows through inventories, educational programs and events as those places where eelgrass meadows have diminished or disappeared, the number of fish species and marine diversity drops," she said. SeaChange plans to map Bowen Island from August 7 to 10, depending on prevailing winds.

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