Why Restore Eelgrass?

Decreasing Worldwide: In the recent paper “A global crisis for seagrass ecosystems”, the authors state that reports of seagrass loss worldwide have increased almost tenfold over the last 40 years (Orth et al. 2006). They indicate that this is the result of a multitude of coastal human population pressures including pollution, physical disturbances, invasive species, and global climate change.  They point out that: “there is a critical need for a targeted global conservation effort...”.  As far as we are concerned, anything that we can do to slow or reverse local losses will benefit the marine environment.

Decreasing Locally: It is clear that Long Island has lost much of the eelgrass coverage from the earliest aerial photos taken in 1930 resulting from acute die-offs (e.g., the “wasting disease” and the “brown tide”) as well as general declines in water quality throughout the 20th century.  More recently, we have found that long-term monitoring within the Peconic Estuary indicates that there has been a general decline in eelgrass coverage over the last decade.  Although the rate of loss varies between the sites monitored, the net result is a decrease in eelgrass.  Unfortunately, monitoring efforts in Long Island Sound and in the South Shore Estuary have only just been initiated recently, so little is known about the long-term trends of these estuaries.

Natural Recovery is Slow: The rate of natural eelgrass recovery can be VERY slow.  We have found that eelgrass meadows on Long Island have rates of rhizome expansion comparable to the global average for Zostera marina, which is approximately 26 cm/yr (Marbá and Duarte 1998). Using this rate and assuming conditions return to optimal for eelgrass growth, it would take over 100 years for a square foot of eelgrass to increase coverage to 1 acre through rhizome expansion alone, which is one means of proliferation for the species.  Infilling by seedlings can increase this rate, but it still would take decades to create a single acre naturally.  For cases where entire meadows have been lost, natural recruitment of seeds from nearby meadows is the only means of recolonization, and this relies heavily on chance and could take hundreds of years to take place. At this rate, even with improvements in conservation and management, eelgrass will not be able to make a significant return to local waters during our lifetimes.  This is where restoration comes in!

It Provides Valuable Ecosystem Services:The ecosystem services provided by seagrasses have a monetary value twice that of other marine habitats including coral reefs, mangroves, and salt marshes, though they receive far less attention (Orth et al. 2006). These services include preventing shoreline erosion, supporting species valuable to the environment and our economy, and increasing water quality (to name a few). Learn more at our ecosystem services page...


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