Eelgrass Meadows

Coastal Marine Restoration

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I.  Seagrasses - Definition and Distribution

A.  Intertidal & Subtidal

B.  Submerged flowering vascular plants (angiosperm)

B.  12 genera (48 species)

C.  Tropical, Temperate, and Subarctic

in Washington:

o Zostera marina (common eelgrass)

o Zostera japonica (Japanese eelgrass)

o Phyllospadix torreyi (Torrey's surfgrass)

o Phyllospadix scouleri (surfgrass)

o phyllospadix serrulatus (surgrass)

west coast distribution map

D.  Adaptive characteristics

E.  Eelgrass (Zostera marina)

Zostera marina Image 1
Zostera marina Image 2
Zostera marina Image 3

functions:

1.  slow current
2.  stabilize bottom sediments
3.  promote sedimentation
4.  inhibit resuspension of O.M.
5.  shelter/habitat
6.  direct/indirect feeding pathways
7.  high productivity & nutrient cycling
8.  take up sulfates & phosphates

Paradoxically, the greatest contribution of seagrass ecosystem to the chains of life...is death. - E. Menez

II.  Environmental Gradients Where Eelgrass is Found

A.  Sediment types

B.  Wave energy regime

C.  Light requirements

• need:  3-10 hours of irradiance-saturated photosynthesis (H_sat) per day
• carbon-balance calculations based on daily metabolic activity (light compensation point)

III.  Common Disturbances & Impacts on Eelgrass

A.  Removal/Alteration of habitat

B.  Alteration of available light (H_sat)

IV.  Restoration Efforts

A. Define appropriate sites & criteria

• extant population?
• available platforms for remote-sensing:
• satellites (limited by depth/clarity of water)
• sub-orbital (limited by depth/clarity of water)
• submarine (ground truth?)
• site history (disturbance)
• site conditions including changes to be made
• timeframe (biological/ecological & socio-political)
• restoration objectives
• no restoration option?
• success criteria
• monitoring expectations

B.  Transplantation

• cores/plugs
• individuals/sprigs (5-15 turions bundled)
• seeds
• turf
• (wire staples/rebar/tubing) - cannot be used with seeding

V.  Recommendations for Transplantation

1. understand the ecosystem; restoration & donor sites (e.g., light, temperature, wave action, edge plants) - no planting may be an option!

2. select site with clear water

3. transplant into an area larger than target (if possible)

4. select site with medium-grained sand

5. select site with low wave energy

6. plant on level substrate

7. plant in areas that pond during low tides...or deeper

8. minimize the holding time of donor stock

9. conduct small-scale experiments prior to transplanting (if possible)

VI.  Greatest Challenges for Eelgrass Restoration