Initial Recovery of Flora and Fauna - Restore America's Estuaries
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Initial Recovery of Flora and Fauna - Restore America's Estuaries

Initial recovery of flora and fauna atrestored mosquito impoundments inIndian River Lagoon, FLMelinda DonnellyPhD Candidate, University of Central FloridaRon Brockmeyer, Linda Walters, WilliamGreening, and Jonas StewartRestore America’s Estuaries Conference, November 15, 2010

Outline• Study Site: Indian RiverLagoon, FL• History and Restoration ofMosquito Impoundments• Monitoring Methods• Results– Initial Recovery of Floraand Fauna– Setting Restoration Targets

Study Site: Indian River Lagoon• Temperate-SubtropicalBoundary• Highly diverseestuaryNew Smyrna BeachFrom Dybas, 2002

What are mosquito impoundments?Purpose: Floodinterior marshto preventmosquitobreedingEstuaryDikeBorrow DitchInterior Marsh

Negative Effects of Mosquito Impoundments• Altered communitycomposition– 21 native and nonnativeterrestrial plantspecies• Decrease in mangroves– Average MangroveDensity: 0.4 trees/m 2• Decreased habitat– Dike unavailable tomarine fishes andinvertebrates– No fiddler crabs on peakof dikeBrazilian pepper(non-native)Sable PalmSouthern Cedar

How are mosquito impoundmentsrestored?RestoredMarshInteriorMarshRemnantBorrowDitch

Natural Regeneration• Natural recruitmentof plant species• Benefits– Low cost– Natural communitystructure• Does it work?

Restored Mosquito Impoundment MonitoringVolusia CountyStart: Fall 2005• 5 impoundments• 2 reference marshes• 5 sites/impoundmentBrevard CountyStart: 2009• 7 impoundments• 1 site/impoundment• Pre/Post-Restorationmonitoring for 2 years

Monitoring MethodsVegetationFiddler CrabsBirdsInterior MarshFishRemnant Borrow Ditch100 m 2quadratElevationRestored Marsh0.25 m 2quadratsShoreline

Volusia County: Restoration of NaturalElevationsMaximum Change inElevation ofReference Marshes:less than 29 cmN = 15During high water season,tidal inundation occurredacross restored surface

Volusia County: Early ColonizersBlack Mangrove,Avicennia germinansSea purslane,Sesuvium portulacastrumPerennial Glasswort,Salicornia perennisSaltwort,Batis maritime

Volusia County: Plant Cover at RestoredMosquito Impoundments2-yr old Black MangroveBlack Mangrove SeedlingsPercent cover in reference marshes:greater than 95%

Volusia County: Brazilian Pepper- Brazilian pepper: nonnativefrom South America- Before restoration:- Relative abundance= 20% ofvegetation- After restoration:- 13 trees over 15 acres ofrestored dike- Elevation: less than 15 cmprevented post-restorationrecruitment

Volusia County: Fiddler CrabsUca pugilatorUca pugnaxMean Density of Fiddler Crabs in Reference Marshes: ~20 crabs/m 2

Volusia County: Birds, Fishes, and MarineInvertebratesBirds: 19 total speciesFishes and Invertebrates: 13 total species

Volusia County: Conclusions• Elevation: key to restoringhydrology• Intact mangrove andhalophytic vegetation atshoreline promotedvegetation recovery• Plant and fiddler crabrecovery occurred withinone month of substrateleveling

Brevard County Impoundment RestorationVolusia County• Objective 1: Elevation• Objective 2: Native plants• Objective 3: Fiddler crabsBrevard County

Brevard County: ElevationTarget: less than 15 cmmaximum heightMean Maximum HeightPre-RestorationPost-Restoration64.1 ± 6.5 cm 13.3 ± 1.0Paired t-test: significant differencein pre- and post-restorationmaximum height(t = 8.2, p

Brevard County: Native Wetland PlantsTargets:Native plants-•5% @ 6 months•10% @ 12 months•15% @ 18 months•25% @ 24 monthsNon-native plants-•less than 10%

Brevard County: Density of Fiddler CrabsTargets: 3 crabs/m 2

Brevard County: Preliminary Conclusions• Restoration of naturalelevation crucial torestoration of habitat– Natural hydrology– Decrease in Brazilian pepper• Natural recruitment ofmangroves and halophytes– Targets exceed for 6 monthsand 1 year• Fiddler crabs present onemonth after restoration

Thanks to…..• Funding: NOAA Recovery Act, Volusia County MosquitoControl, St. Johns River Water Management District,University of Central Florida, Florida Exotic Pest PlantCouncil• Canaveral National Seashore, Merritt Island NationalWildlife Refuge, NASA, Mosquito Lagoon AquaticPreserve• Family, friends, and UCF undergraduate and graduatestudents for lab and field help

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