1. Introduction to Barrier Island Ecology Biology 366 Ecology 16 April 2002

2. Barrier Island Transect Beach and DunesBeach and Dunes Shrub Thicket and Maritime ForestShrub Thicket and Maritime Forest Freshwater WetlandsFreshwater Wetlands Tidal MarshTidal Marsh Estuarine Waters/Sand and Mud FlatsEstuarine Waters/Sand and Mud Flats

3. Dune Formation Sand, moved by the process of saltation, accumulates around objects including vegetation and flotsam

4. Dune Formation SandWindObject Elements required for dune formationElements required for dune formation

5. American Beachgrass (Ammophila breviligulata)

6. Sea Oats (Uniola paniculata)

7. Panic Grass (Panicum amarum)

8. Saltmeadow Cordgrass (Spartina patens)

9. Strand Line or Wrack Line Line of debris at spring tideLine of debris at spring tide Debris is called “wrack”Debris is called “wrack” Most dunes form hereMost dunes form here

10. Strand Line or Wrack Line Large quantities of sand moved across strandLarge quantities of sand moved across strand Common on prograding (growing) beachesCommon on prograding (growing) beaches Rare on eroding beachesRare on eroding beaches

11. Dune Environments Youngest strand lines lie most seawardYoungest strand lines lie most seaward Multiple dune ridges form as strand lines are colonizedMultiple dune ridges form as strand lines are colonized Oldest - - - - - - > Youngest

12. Dune Environments Dunes and colonizing plants grow in concertDunes and colonizing plants grow in concert Year 3 Year 2 Year1

13. Dune Environmental Conditions Low soil nutrients (N and P)Low soil nutrients (N and P) Desiccating windsDesiccating winds Blowing sandBlowing sand

14. Dune Environmental Conditions Air and soil temperatures are highly variableAir and soil temperatures are highly variable

15. Dune Processes Unvegetated dunes “migrate” or move from 15 m annuallyUnvegetated dunes “migrate” or move from 15 m annually Migrating dunes engulf surroundingsMigrating dunes engulf surroundings  Natural revegetation a long term process

16. Blowouts Occur when vegetation mantle is destroyedOccur when vegetation mantle is destroyed Difficult to stop, once startedDifficult to stop, once started Creates environment called “slack”Creates environment called “slack” blowout

17. Natural and Man-induced Impacts on Dunes Oceanic overwashOceanic overwash “erosion”“erosion” Off-road vehicle (ORV) trafficOff-road vehicle (ORV) traffic Sand fencing: wooden, brush, treesSand fencing: wooden, brush, trees Washovers

18. Salt Aerosol Impacts Salt aerosol effects on plants Salt aerosol source this side

19. Source of Salt Aerosols Salt Aerosols

20. Salt Aerosol Impact on Plants Source of salt aerosol (ocean side)

21. Salt Aerosol Impact on Plants Generally decreases from strand line, landwardGenerally decreases from strand line, landward Highest on foredunesHighest on foredunes Lowest in slacks and lee of dunesLowest in slacks and lee of dunes

22. Coastal Communities and Processes Beach and DunesBeach and Dunes Shrub Thicket and Maritime ForestShrub Thicket and Maritime Forest Freshwater WetlandsFreshwater Wetlands Tidal MarshTidal Marsh Estuarine Waters/Sand and Mud FlatsEstuarine Waters/Sand and Mud Flats

23. Shrub Thicket Environments Early colonizers (survive low nutrients)Early colonizers (survive low nutrients) Best examples are in dune slacksBest examples are in dune slacks Reduced salt aerosol environment allows arborescent vegetation to flourishReduced salt aerosol environment allows arborescent vegetation to flourish

24. Wax Myrtle (Myrica pennsylvanica) Northern Bayberry is common in thickets from Cape Hatteras northward into New EnglandNorthern Bayberry is common in thickets from Cape Hatteras northward into New England Bayberry candles are made from the waxy coating on the berriesBayberry candles are made from the waxy coating on the berries

25. Yaupon (Ilex vomitoria)

26. Maritime Forest Environments Develop under the influence of salt aerosolsDevelop under the influence of salt aerosols Restricted distributionRestricted distribution Shear edge created by salt aerosolsShear edge created by salt aerosols

27. Maritime Forest Environments Species adapted to:Species adapted to: –Low salt aerosols –low soil nutrients –sandy soils Salt aerosols control location and structure of the maritime forestSalt aerosols control location and structure of the maritime forest

28. Maritime Forest Environments Vines are commonVines are common Tree leaves small, thick, evergreenTree leaves small, thick, evergreen Live Oak (Quercus virginiana)

29. Bear oak (Quercus illicifolia) common along New England maritime-influence forests

30. Southern Red Oak (Quercus falcata) Common in Mid-Atlantic maritime forests

31. Red Cedar (Juniperus virginiana) Salt aerosol damage ocean

32. American Holly (Ilex opaca)

33. Loblolly Pine (Pinus taeda) Loblolly pine is the most common pine in the maritime forest. It typically is successional and is replaced by live or laurel oak in the southeastern US.

34. Dogwood (Cornus florida) Poison Ivy (Rhus toxicodendron) Woodbine (Parthenocissus quinquefolia)

35. Development of Maritime Forests Develop on coastal dune systemsDevelop on coastal dune systems Sterile sandy soilsSterile sandy soils Hummocky topographyHummocky topography Begin as scattered shrubsBegin as scattered shrubs

36. Impact of hurricanes on maritime forest vegetation. Pines are typically snapped off; cabbage palms survive. Live oak and magnolia have branches and leaves ripped off. Natural Impacts on Maritime Forests Large migrating dunes are capable of overwhelming shrub and forest vegetation

37. Significant Human Impacts Fragmentation occurs when development occurs within a continuous forestFragmentation occurs when development occurs within a continuous forest Forest opened to salt aerosol impacts when development occurs

38. Freshwater Wetland Environments Ponds, swamps, marshesPonds, swamps, marshes Form where water table intersects ground surfaceForm where water table intersects ground surface

39. Freshwater Wetland Environments Receive groundwater input from adjacent dunesReceive groundwater input from adjacent dunes Influenced by groundwater and rainfallInfluenced by groundwater and rainfall Water flows from adjacent dunes into slough between dunes

40. Freshwater Wetlands Cattails (Typha spp.)Cattails (Typha spp.) Bulrush (Scirpus spp.)Bulrush (Scirpus spp.)

41. Tidal Marsh Environments Develop in areas protected from wave attackDevelop in areas protected from wave attack Topographically flat, incised with drainage creeksTopographically flat, incised with drainage creeks

42. Tidal Marsh Environments Alternately exposed and covered by tides dailyAlternately exposed and covered by tides daily “Pulse- stable” environment s“Pulse- stable” environment s

43. Tidal Marsh Environment Saltmeadow Cordgrass (Spartina patens)Saltmeadow Cordgrass (Spartina patens) Smooth Cordgrass (Spartina alterniflora)Smooth Cordgrass (Spartina alterniflora)

44. Zonation Cordgrass dominant above and below mean tide levelCordgrass dominant above and below mean tide level Many other species dominant above average high tidesMany other species dominant above average high tides

45. Black Needlerush (Juncus roemerianus) Black Needlerush is common at the upper edge of the tidal marsh where the tide floods only occasionally Black Needlerush

46. Sea Ox-eye (Borrichia frutescens) Sea Lavender (Limonium carolinianum)

47. Glassworts (Salicornia spp.) These succulent plants grow in the most saline environments in the tidal marsh area

48. Formation of Tidal Marsh Sand and mudflats colonized by smooth cordgrassSand and mudflats colonized by smooth cordgrass –must reach critical elevation –seed falls on flats –spread by rhizomes Typical environments colonized by smooth cordgrass primarily by seeds

49. Formation of Tidal Marsh Sand flats are colonized by clumps of smooth cordgrass. Alternatively, the sand flats can be colonized by germinating seeds of smooth cordgrass. Colonization by Spartina alterniflora

50. Formation of Tidal Marsh Sand flats may become uniformly vegetated in 2- 5 yearsSand flats may become uniformly vegetated in 2- 5 years Creeks become incised as community maturesCreeks become incised as community matures

51. Human Impacts Finger canals (now outlawed in all states)Finger canals (now outlawed in all states) Point and non- point source runoffPoint and non- point source runoff

52. Mudflats and Sandflats No rooted aquatic vegetationNo rooted aquatic vegetation Significant infauna (clams, worms, etc.)Significant infauna (clams, worms, etc.) Important habitat for organisms in intertidal environmentsImportant habitat for organisms in intertidal environments

53. Submerged Aquatic Vegetation Typically composed of seagrassesTypically composed of seagrasses –Marine flowering plants –13 genera; 58 species worldwide Grow in shallow subtidal or intertidal water on soft muds and sandy sediments (some on rocky substrates)Grow in shallow subtidal or intertidal water on soft muds and sandy sediments (some on rocky substrates) Evolved from terrestrial grassesEvolved from terrestrial grasses Turtle Grass, Thalassia testudinum

54. Lifestyle Requirements for Seagrasses Must be adapted to saline waters (true halophyte)Must be adapted to saline waters (true halophyte) Must be able to grow completely submergedMust be able to grow completely submerged Must be securely anchored in the substrate (some species are anchored to rocky substrates)Must be securely anchored in the substrate (some species are anchored to rocky substrates) Must be able to flower, fruit and produce seeds in waterMust be able to flower, fruit and produce seeds in water Leaves and stems lack waxy cuticle typical of terrestrial plantsLeaves and stems lack waxy cuticle typical of terrestrial plants Typically possess aerenchyma tissue for bouyancyTypically possess aerenchyma tissue for bouyancy

55. Occurrence Worldwide in distributionWorldwide in distribution In US, found on Atlantic, Pacific, and Gulf coastsIn US, found on Atlantic, Pacific, and Gulf coasts 90% of seagrasses in US are in Gulf of Mexico90% of seagrasses in US are in Gulf of Mexico –Major beds in Chesapeake Bay, Florida, Texas and California Occur primarily in “beds,” typically patchy in natureOccur primarily in “beds,” typically patchy in nature Grasses typically found in 10-15 m of water, but have been found down to 130 feetGrasses typically found in 10-15 m of water, but have been found down to 130 feet

56. Ecology of Seagrass Beds Seagrass beds are important to:Seagrass beds are important to: –Grazers—manatees, ducks, etc. –Epiphyte grazers—feed on seagrass epiphytes—sea urchins, fish, etc. epiphytes—sea urchins, fish, etc. –Detritus feeders—feed on decaying organic matter organic matter –Shelter for conch, starfish, sand dollars, etc dollars, etc Substrate and food for bay barnacles, sea squirts, sponges, isopods, amphipods, snails, seahorses, anchovies, silversides, shrimp, blue crabs, waterfowl and othersSubstrate and food for bay barnacles, sea squirts, sponges, isopods, amphipods, snails, seahorses, anchovies, silversides, shrimp, blue crabs, waterfowl and others

57. Ecology of Seagrass Beds Bind sediments with extensive rhizomes and rootsBind sediments with extensive rhizomes and roots Baffle waves and currentsBaffle waves and currents Trap sediments/clear the water columnTrap sediments/clear the water column Improve water quality by taking up nutrients (epiphytes do the same)Improve water quality by taking up nutrients (epiphytes do the same) Important in oxygenating waterImportant in oxygenating water Seagrass systems protected under federal “no-net-loss” policy for wetlandsSeagrass systems protected under federal “no-net-loss” policy for wetlands

58. Vulnerability of Seagrass Beds Conditions resulting in reduction of seagrass bedsConditions resulting in reduction of seagrass beds –Nutrient loading –Light reduction –Physical destruction Rate of loss: weeks to monthsRate of loss: weeks to months Rate of recovery: yearsRate of recovery: years –Vegetatively slow recovery –Seeding shows more rapid recovery Propeller scars on seagrass beds near Windley Key, Florida Keys

59. Common Seagrasses of the Eastern and Gulf US Manatee Grass Syringodium filiforme Shoal Grass Halodule wrightii Widgeon Grass Ruppia maritima Turtle Grass Thalassia testudinum Eel Grass Zostera marina Paddle Grass Halophila decipiens

60. Causes of Decline in Seagrasses Dredge and fill operationsDredge and fill operations Mooring scarsMooring scars Propeller scarsPropeller scars Vessel wakesVessel wakes Jet skisJet skis Fish and shellfish harvesting techniquesFish and shellfish harvesting techniques Sewage outfalls Thermal pollution Disease Storms Ice scour Epiphyte load Burrowing shrimp Green algae