1. Seagrass restoration in Little Lagoon
May 2nd and 3rd 2009
Bart Christiaen

2. What are seagrasses? flowering plants salt water Turtlegrass
Definition
Seagrasses in Perdido
Widgeongrass not ‘true seagrass’
Turtlegrass
Shoalgrass
Widgeongrass

3. Why are they important? Food & shelter
seagrasses & epiphytic algae = base foodchain

4. Why are they important? sediment stabilization input organic matter
sediment chemistry
roots = stabilization = less ‘cloudy’ water when windy
when above/belowground tissue dies = degraded by bacterial community = input organic matter = substrate many organisms
photosynthesis (plants use CO2 + light to create sugars + O), excess O2 transported to belowground tissue for respiration, part of it leaks out = microhabitat for bacteria (nitrification) + change in sediment chemistry

5. Problem: worldwide decline
decline since 1970 = only what has been reported/researched = tip of iceberg
black squares = caused by anthropogenic influence
seagrass declines reported since 1970 (Short & Echeverria 1996)

6. Underlying cause ...
population growth + large part of population lives near the sea = impact on coastal habitat

7. For example: in Florida
Population increase
Decrease in seagrass cover
example Florida
More people = more opportunity for damaging activities

8. Mechanism Direct effects: prop scarring, construction, ...
direct: prop scarring (boating)
construction (marinas and docks)

9. Mechanism Indirect effects: shading Indirect:
construction = damaging near shore vegetation + marsh = destroy buffer for runoff. storm runoff = major source for nutrients + sediment load in estuaria & lagoons = shading
dredging = sediment resuspension = shading
more people = more nutrients. algae (macro/epiphytic/phytoplankton) grow faster than seagrasses = are the ones that profit from nutrient increase. live on leaves or in water column = shading

10. Shading
shading: direct effect: less light = less photosynthesis = slower plant growth
BUT also less O2 exuded by roots = sediment chemistry changes: toxic substances in sediment (sulfides) are normally neutralized by the protective O2 layer around the roots. less O2 = roots & rhizomes die off = less nutrient uptake through roots (‘positive’ feedback) = even more trouble for plant

11. What can we do? Government: protection of existing beds
regulation of dredging, watershed development, ...
Citizens:
responsible boating

12. What can we do?
prop scars

13. If water quality is sufficient
Seagrass restoration

14. Seagrass restoration in Little Lagoon

15. Not as simple as it looks
Notoriously high failure rate
You’ve got to do it right!

16. Site selection
Site selection based on water quality, sediment, exposure to wave energy,...
NE corner of Bon Secour Wildlife Refuge, near the Jeff Friend Trail
3 sites researched in 2008, differences in light & salinity
Best site near Jeff Friend Trail

17. Method selection & test
Best candidate for restoration: shoalgrass
grows rapid + needs less light than turtle grass
deeper root system than widgeongrass = more resistant for wave action

18. Method selection & test
Appropriate method: transplantation
% survival shoalgrass plugs
weeks
% survival
Different methods for restoration. Plants that form seeds = seeding, for example eelgrass restoration (problem, shoalgrass does not flower frequently). Some plants: lab propagation & tissue culture, for example widgeongrass (problem, shoalgrass propagation more difficult)
Transplantation = take plugs from donor site and bring them to new sites. why? shoalgrass = mostly vegetative propagation. bring living plants in new (suitable) site = rapid growth if conditions are right. But, potential for damaging donor sites! Not that big of a problem for shoalgrass though (rapid vegetative expansion). Still: small plugs, low density + only trained persons take plugs.
Test transplant experiment in Little Lagoon: succes! 2 treatments (protected against ‘bioturbation’ = damage by certain animals, confr. rays, bluecrabs + unprotected)
80-95% survival after 1 year + plants start to spread.

19. Method selection & test
how it looked in February 2009

20. It works = bigger scale!
Bigger scale experiment: 8 shallow plots + 8 plots at intermediate depth. Hope = going to spread out over time + for continuous bed.

21. But ...
Seagrass transplantation is a lot of work

22. We need help When? → 2nd & 3rd May of 2009 → 10.30 in the morning
Where? → parking lot of Jeff Friend Trail
What? → short demonstration
→ planting together with students
from Dauphin Island Sea Lab
→ knee deep – waist deep water
DISL will provide sunscreen & water & snacks
you will get wet & a bit muddy = waders or dirty clothes + sunglasses!
shallow water + lots of Sealab people around for assistance

23. We need help THANK YOU If you want to volunteer, please contact
Dennis Hatfield
Bart Christiaen
THANK YOU

24. If you have any questions
Please ask!