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

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

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

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

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)

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

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

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

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

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

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

What can we do? prop scars

If water quality is sufficient Seagrass restoration

Seagrass restoration in Little Lagoon

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

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

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

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.

Method selection & test how it looked in February 2009

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.

But ... Seagrass transplantation is a lot of work

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

We need help THANK YOU If you want to volunteer, please contact Dennis Hatfield Bart Christiaen (bchristiaen@disl.org) THANK YOU

If you have any questions Please ask!