Submerged Aquatic Vegetation

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Submerged Aquatic Vegetation
WHAT IS IT AND WHY IS IT IMPORTANT?
Image provided by Ronald C. Phillips
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What Is Submerged Aquatic Vegetation (SAV)?

• SAV consists of plants that spend their life
  cycle completely submerged
• Includes algae, but usually refers to complex
  plants such as seagrasses
• SAV does not include marsh grasses

Seagrasses
Image provided by Ronald C. Phillips
Marsh grasses
Image provided by NOAA Department of Commerce
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What Are Seagrasses?
Paige Gill - Florida Keys NMS

• Type of SAV
• Exhibit seasonal growth
• Contribute to a rich, productive ecosystem
• Provide oxygen, food and habitat for many animals

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Where Do Seagrasses Grow?

• They require habitats where sunlight can reach
  the bottom
• They typically prefer shallow clear water
• They grow close to the shore in many coastal
  regions
• They occur from the Tropics to the Arctic

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Why Should We Care about Seagrasses?

• They release oxygen into the water
• They provide habitat and shelter
• They are a food resource
• They help stabilize the shoreline
• They help maintain water quality

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Seagrasses Release Oxygen into the Water

• Seagrasses use sunlight to produce oxygen
• Many economically important fish and shellfish
  require oxygen

Image provided by Fred Short
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Seagrasses Provide Habitat and Shelter

• Leaves provide habitat for tiny plants
• These tiny plants are the food resource of many
  economically important finfish, shellfish, and
  crustaceans.
• Leaves provide hiding spots for juvenile finfish
  and other animals
• Roots and stems prevent efficient foraging by
  predators who dig for prey

Image provided by SFWMD
Image provided by Heather Dine
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Seagrasses Are a Food Resource

• Seagrasses are a primary food source for manatees
  and sea turtles
• Many migratory waterfowl such as the Canada Goose
  and Black Brant consume seagrass

Image provided by Ronald C. Phillips
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Seagrasses Help Stabilize the Shoreline

• Roots trap sediments
• Seagrasses buffer the shore from storm effects
• They help prevent erosion

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Seagrasses Help Maintain Water Quality

• Roots trap sediments and promote water clarity
• They reduce sediment stirring caused by currents
• Stems and roots hold dead materials in place for
  decomposition

Images provided by Ronald C. Phillips
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Why Are Seagrasses Threatened?

• Seagrasses grow close to the shore and coastal
  areas are naturally dynamic
• Seagrases grow in areas that typically have
  increased development and recreational pressures
• There are laws that protect seagrasses, but it is
  hard to protect what you cant see

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Natural Threats to Seagrasses

• Overgrazing can decimate seagrass beds
• Storms can uproot or bury seagrasses
• Drought can change water levels, which can expose
  seagrasses
• Changes in rainfall can alter salinity, which can
  stress or kill seagrasses
• Outbreaks of diseases can cause diebacks

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Human Threats to Seagrasses

• Fertilizer and other chemical runoff reduce water
  quality
• Reckless boating can contribute to prop scars
• Docks shade seagrass beds
• Dredging destroys habitat
• Sediment runoff buries seagrasses and clouds
  water
• Certain shellfish harvesting methods destroy
  seagrass beds

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Can SAV Be Harmful?

• Some SAV can cause problems
• These plants can grow quickly and crowd out
  seagrasses
• They often thrive in polluted waters
• Their quick growth may lead to large population
  sizes
• They may contribute to fish and shellfish
  die-offs
• Plants clog waterways and choke boat engines

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Why Should We Protect Seagrasses?

• Seagrasses supports a healthy coastal environment
• They are important in maintaining recreational
  and commercial fisheries
• They are legally protected
• Seagrasses help reduce erosion

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How Do We Know Where Seagrasses Live?

• Field monitoring
• Underwater surveys
• Underwater photographs and videography
• Remote sensing technology
• Aerial imagery
• Underwater sensors

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How Can You Help?

• Always use pump-out stations to dispose of boat
  waste
• Avoid vegetated shallows when planning dredging
  or pier construction
• Participate in water quality monitoring programs
• Practice responsible boating and navigation

• Help environmental organizations plant seagrasses
• Use environmentally friendly landscaping
  techniques