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SubmergedAquaticVegetation
- 1. The Relationship Between Shoreline Characteristics and Nearshore Submerged Aquatic Vegetation Bridget Smith, Chris Patrick, Meghan Williams, Don Weller
- 3. SAV Decline Li et al. 2007 Estuaries & Coasts Patrick et al. 2014 Estuaries & Coasts
- 5. Shoreline Types Natural Hardened Mechanisms of change - Suspend sediment, decreasing water clarity - Scour away sensitive beds - Deepen the adjacent shore through bottom scour
- 6. Slope 0 m -3 m 0 m -3 m
- 7. Shoreline Hardening and SAV Effects of Shoreline Alteration and Other Stressors on Submerged Aquatic Vegetation Riprap and bulkhead negative predictors of SAV abundance at the subestuary scale Patrick et al. 2014 Estuaries & Coasts The Relationship Between Shoreline Hardening and Adjacent Submerged Aquatic Vegetation Less SAV directly adjacent to bulkhead Patrick et al. 2014 Estuaries & Coasts (in review)
- 8. Shoreline Hardening: Further Questions How does the length of shorelines (natural, riprap, and bulkhead) influence the abundance of SAV? How far do these offshore effects extend? Does this differ for different shoreline types? How are shoreline structures related to nearshore bathymetry?
- 10. Shoreline Scale Shoreline LengthDistance to ShoreDepth
- 11. SAV Presence and Mean Density Presence: The fraction of years SAV is present from 1984 to 2012 <10% 10-40% 40-70% 70-100% Coverage
- 12. SAV Presence and Mean Density Presence: 0.607 Mean Density: 1.714 <10% 10-40% 40-70% 70-100% Coverage
- 13. SAV Presence and Mean Density Presence: 0.143 Mean Density: 0.321 <10% 10-40% 40-70% 70-100% Coverage
- 14. Hypotheses Steeper slopes occur off of hardened shorelines. SAV adjacent to natural shorelines will have greater presence and mean density than SAV adjacent to hardened shorelines. For natural shorelines, there will be a positive relationship between shore length and SAV presence and mean density.
- 15. Methods
- 16. Data • Shoreline condition: length and location of shoreline types • SAV spatial extent from 1984 to 2012 from aerial photography • Bathymetry
- 17. Variables Response Predictor Slope Depth SAV Presence SAV Mean Density Shoreline Type Shoreline Type Depth Shore Length Distance to Shore Salinity Zone
- 18. Statistical Analyses Physical Characteristics SAV Presence and Mean Density ANOVA Categorical variable: shore type Continuous variables: depth and slope ANOVA Categorical variables: shore type and salinity zones ANCOVA Categorical variable: shore type Continuous variables: shore length, distance to shore, depth If results are significant, run linear regression by shore type
- 19. Slope Analysis
- 20. SAV Presence and Density Analysis
- 21. Results
- 25. Results SAV Presence and Mean Density
- 26. Shore Type P value <0.001 Natural shorelines also has the highest mean density of SAV
- 27. Depth and Shore Length Interaction P value = 0.007 Natural Shorelines: Presence by Depth and Shore Length Bulkhead Shorelines: Presence by Depth and Shore Length Interaction P value = 0.004 Riprap not significant. Depth Depth Presence Presence
- 28. Depth and Distance to Shore Interaction P value < 0.001 Natural Shoreline: SAV Mean Density by Depth and Distance to Shore Depth MeanDensity
- 29. Depth and Distance to Shore Interaction P value < 0.05Interaction P value < 0.001 Riprap Shoreline: SAV Mean Density by Depth and Distance to Shore Depth MeanDensity Bulkhead Shoreline: SAV Mean Density by Depth and Distance to Shore Mean Density Depth
- 30. Salinity P value < 0.001 Highest presence and mean density in the polyhaline zone
- 31. Salinity Interaction P value < 0.001
- 32. Take Away Points More gradual slopes along natural shorelines Natural shorelines have greater SAV presence and mean density than hardened shorelines 0 3 Dept h Natural Riprap and Bulkhead Shoreline Type Presence Density Length Distance Natural + + + + Bulkhead - - NS + Riprap - - NS NS
- 33. Next Steps Repeat analysis when better bathymetry becomes available Examine how shoreline length and shore type are related to slope
- 34. Acknowledgements Chris Patrick Meghan Williams Donald Weller Smithsonian Environmental Research Center Virginia Institute of Marine Science NOAA USGS
Hinweis der Redaktion
- Ecosystem services: primary production, provide carbon to detritivores, carbon sequestration, filter nutrient inputs, nursery ground for fish Biological sentinels for water quality and sediment inputs (Orth et al 2006)
- Agriculture: ¼ of land in chesapeake bay devoted to agriculture. Largest source of nutrient and sediment pollution entering bay
- People moving to coast, sea level rise->will be a lot more hardening
- Bulkhead: vertical wall, water depth often a meter + Reflected waves- damage sav, bury them with sediment
- Add graphic from slope creation Slope influences what potential habitat is available- steeper slope=takes less distance to reach -3 m deep Bottom scour from hardened shorelines could cause changes in slope
- Riprap: poorer resilience, do not recover as quickly from temporary declines Armoring can change near shore hydrology, morphology, water clarity, and sediment composition Many subestuaries in chesapeake bay up to 50% armored Significant because of populations moving to coast and sea level rise- hardening will increase
- Shore length, how far offshore effects extend, interaction with nearshore bathymetry Mention bathymetry last-> transition to slope
- Add photos
- edit
- Give same colors
- Mean density interaction only significant for natural shorelines
- Redo salinity zone image. Fix graph.
- edit