Important Notes

The purpose of this script is to provide a report summary of SAV analysis. The script used for analysis is SEACAR_SAV_BB_script_website.R.

All scripts and outputs can be found on the SEACAR GitHub repository:

https://github.com/FloridaSEACAR/SEACAR_Trend_Analyses

This script is based off of code originally written by Stephen Durham with comments by Marcus W. Beck. Modified by Tyler Hill.

The file being used for the analysis is: All_SAV_Parameters-2026-Mar-06.txt

Alligator Harbor Aquatic Preserve

SAV LME Results for Alligator Harbor Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae Decreasing trend 2009 - 2023 79.40 -2.36 0.03
Shoal grass No detectable trend 2008 - 2023 29.79 -0.50 0.47
Star grass Insufficient data - - - -
Widgeon grass Insufficient data - - - -
Manatee grass Decreasing trend 2008 - 2023 47.86 -1.23 0.03
Turtle grass No detectable trend 2008 - 2023 30.97 -0.45 0.38

Annual decreases in percent cover were observed for manatee grass (-1.23%) and drift algae (-2.36%). No detectable change in percent cover was observed for shoal grass and turtle grass. Trends in percent cover could not be evaluated for star grass and widgeon grass due to insufficient data.

Map showing SAV sampling sites within the boundaries of Alligator Harbor Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Alligator Harbor Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Apalachicola Bay Aquatic Preserve

SAV LME Results for Apalachicola Bay Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae Decreasing trend 2003 - 2023 84.82 -2.63 0.00
Shoal grass No detectable trend 2008 - 2023 31.69 0.92 0.49
Widgeon grass Insufficient data - - - -

An annual decrease in percent cover was observed for drift algae (-2.63%). No detectable change in percent cover was observed for shoal grass. Trends in percent cover could not be evaluated for widgeon grass due to insufficient data.

Map showing SAV sampling sites within the boundaries of Apalachicola Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Apalachicola Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Apalachicola National Estuarine Research Reserve

SAV LME Results for Apalachicola National Estuarine Research Reserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae Decreasing trend 2003 - 2023 60.31 -1.84 0.03
Shoal grass No detectable trend 2008 - 2023 42.98 -0.24 0.73
Star grass Insufficient data - - - -
Widgeon grass Insufficient data - - - -
Manatee grass Insufficient data - - - -

An annual decrease in percent cover was observed for drift algae (-1.84%). No detectable change in percent cover was observed for shoal grass. Trends in percent cover could not be evaluated for manatee grass, star grass, and widgeon grass due to insufficient data.

Map showing SAV sampling sites within the boundaries of Apalachicola National Estuarine Research Reserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Apalachicola National Estuarine Research Reserve. The point size reflects the number of samples at a given sampling site.

Banana River Aquatic Preserve

SAV LME Results for Banana River Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae Insufficient data - - - -
Shoal grass Decreasing trend 1997 - 2025 32.71 -1.27 0.00
Halophila spp. No detectable trend 1997 - 2025 0.50 -0.01 0.14
Widgeon grass Decreasing trend 1997 - 2025 7.80 -0.34 0.00
Manatee grass No detectable trend 1997 - 2025 0.09 0.00 0.07
Turtle grass Model did not fit the available data - - - -
Total SAV Decreasing trend 1994 - 2025 39.07 -1.52 0.00
Total seagrass Insufficient data - - - -

Annual decreases in percent cover were observed for total SAV (-1.52%), shoal grass (-1.27%), and widgeon grass (-0.34%). No detectable change in percent cover was observed for Halophila spp. and manatee grass. Trends in percent cover could not be evaluated for total seagrass and drift algae due to insufficient data, and the model could not be fitted for turtle grass.

Map showing SAV sampling sites within the boundaries of Banana River Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Banana River Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Big Bend Seagrasses Aquatic Preserve

SAV LME Results for Big Bend Seagrasses Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae Increasing trend 2000 - 2024 5.45 0.81 0.00
Shoal grass Decreasing trend 2000 - 2024 24.83 -0.43 0.00
Star grass No detectable trend 2000 - 2024 18.55 -0.13 0.31
Widgeon grass No detectable trend 2001 - 2024 25.94 -0.28 0.60
Manatee grass Decreasing trend 2000 - 2024 35.95 -0.43 0.00
Turtle grass Decreasing trend 2000 - 2024 42.52 -0.48 0.00

An annual increase in percent cover was observed for drift algae (0.81%). Annual decreases in percent cover were observed for manatee grass (-0.43%), shoal grass (-0.43%), and turtle grass (-0.48%). No detectable change in percent cover was observed for star grass and widgeon grass.

Map showing SAV sampling sites within the boundaries of Big Bend Seagrasses Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Big Bend Seagrasses Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Biscayne Bay Aquatic Preserve

SAV LME Results for Biscayne Bay Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Attached algae No detectable trend 2008 - 2024 -0.03 0.01 0.10
Drift algae Decreasing trend 1999 - 2024 10.73 -0.31 0.00
Shoal grass Decreasing trend 1999 - 2024 8.21 -0.23 0.00
Halophila spp. Decreasing trend 2000 - 2024 0.67 -0.02 0.01
Widgeon grass Model did not fit the available data - - - -
Manatee grass Decreasing trend 1999 - 2024 14.75 -0.37 0.00
Turtle grass Decreasing trend 1999 - 2024 44.97 -1.37 0.00
Total SAV No detectable trend 1999 - 2024 51.24 -0.21 0.26
Total seagrass Increasing trend 2005 - 2024 17.14 0.61 0.00

An annual increase in percent cover was observed for total seagrass (0.61%). Annual decreases in percent cover were observed for Halophila spp. (-0.02%), manatee grass (-0.37%), shoal grass (-0.23%), turtle grass (-1.37%), and drift algae (-0.31%). No detectable change in percent cover was observed for total SAV and attached algae. The model could not be fitted for widgeon grass.

Map showing SAV sampling sites within the boundaries of Biscayne Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Biscayne Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Boca Ciega Bay Aquatic Preserve

SAV LME Results for Boca Ciega Bay Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae Insufficient data - - - -
Shoal grass No detectable trend 1998 - 2024 47.98 -0.2 0.38
Manatee grass Model did not fit the available data - - - -
Turtle grass Decreasing trend 1998 - 2024 52.33 -0.5 0.05
Halophila, unk. Insufficient data - - - -

An annual decrease in percent cover was observed for turtle grass (-0.50%). No detectable change in percent cover was observed for shoal grass. Trends in percent cover could not be evaluated for unknown Halophila and drift algae due to insufficient data, and the model could not be fitted for manatee grass.

Map showing SAV sampling sites within the boundaries of Boca Ciega Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Boca Ciega Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Cape Haze Aquatic Preserve

SAV LME Results for Cape Haze Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Attached algae Insufficient data - - - -
Drift algae Increasing trend 2003 - 2024 -11.48 1.25 0.02
Shoal grass No detectable trend 1998 - 2024 21.98 -0.33 0.35
Manatee grass No detectable trend 1998 - 2024 31.32 -0.16 0.83
Turtle grass No detectable trend 1998 - 2024 24.58 0.22 0.48
Total seagrass No detectable trend 1998 - 2024 31.20 -0.39 0.32

An annual increase in percent cover was observed for drift algae (1.25%). Total seagrass, manatee grass, shoal grass, and turtle grass showed no detectable change in percent cover. Trends in percent cover could not be evaluated for attached algae due to insufficient data.

Map showing SAV sampling sites within the boundaries of Cape Haze Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Cape Haze Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Cockroach Bay Aquatic Preserve

SAV LME Results for Cockroach Bay Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Attached algae Insufficient data - - - -
Drift algae Insufficient data - - - -
Shoal grass Increasing trend 2000 - 2024 19.22 0.53 0.02
Manatee grass No detectable trend 2000 - 2024 35.78 0.83 0.08
Turtle grass No detectable trend 2000 - 2024 16.24 0.18 0.42
Halophila, unk. Insufficient data - - - -

An annual increase in percent cover was observed for shoal grass (0.53%). No detectable change in percent cover was observed for manatee grass and turtle grass. Trends in percent cover could not be evaluated for unknown Halophila, attached algae, and drift algae due to insufficient data.

Map showing SAV sampling sites within the boundaries of Cockroach Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Cockroach Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Estero Bay Aquatic Preserve

SAV LME Results for Estero Bay Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Attached algae No detectable trend 2002 - 2024 8.13 -0.20 0.39
Drift algae No detectable trend 2002 - 2024 20.04 -0.29 0.38
Shoal grass Decreasing trend 2002 - 2024 37.07 -0.83 0.00
Paddle grass No detectable trend 2002 - 2023 18.90 -0.06 0.92
Star grass Model did not fit the available data - - - -
Manatee grass No detectable trend 2003 - 2021 26.94 -0.97 0.35
Turtle grass Decreasing trend 2002 - 2024 22.45 -0.48 0.01
Total seagrass Decreasing trend 2006 - 2024 47.66 -1.27 0.02
Halophila, unk. Model did not fit the available data - - - -

Annual decreases in percent cover were observed for total seagrass (-1.27%), shoal grass (-0.83%), and turtle grass (-0.48%). Manatee grass, paddle grass, attached algae, and drift algae showed no detectable change in percent cover. A model could not be fitted for unknown Halophila and star grass.

Map showing SAV sampling sites within the boundaries of Estero Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Estero Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Florida Keys National Marine Sanctuary

SAV LME Results for Florida Keys National Marine Sanctuary
Species Statistical Trend Period of Record LME Intercept LME Slope p
Attached algae No detectable trend 2008 - 2025 0.07 0.00 0.20
Drift algae Decreasing trend 1999 - 2025 8.74 -0.21 0.00
Shoal grass Decreasing trend 1996 - 2025 6.66 -0.24 0.00
Halophila spp. No detectable trend 2005 - 2025 0.07 0.00 0.41
Widgeon grass No detectable trend 2005 - 2025 -0.03 0.00 0.13
Manatee grass Decreasing trend 1996 - 2025 4.94 -0.11 0.02
Turtle grass Decreasing trend 1996 - 2025 42.29 -1.38 0.00
Total SAV No detectable trend 1999 - 2025 31.28 0.24 0.12
Total seagrass Increasing trend 2005 - 2025 15.77 0.28 0.00

An annual increase in percent cover was observed for total seagrass (0.28%). Annual decreases in percent cover were observed for manatee grass (-0.11%), shoal grass (-0.24%), turtle grass (-1.38%), and drift algae (-0.21%). Total SAV, Halophila spp., widgeon grass, and attached algae showed no detectable change in percent cover.

Map showing SAV sampling sites within the boundaries of Florida Keys National Marine Sanctuary. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Florida Keys National Marine Sanctuary. The point size reflects the number of samples at a given sampling site.

Fort Pickens State Park Aquatic Preserve

SAV LME Results for Fort Pickens State Park Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Shoal grass No detectable trend 2016 - 2025 57.58 -0.38 0.30
Widgeon grass Insufficient data - - - -
Manatee grass Insufficient data - - - -
Turtle grass No detectable trend 2016 - 2025 24.56 0.87 0.14
Total SAV No detectable trend 2016 - 2025 76.79 -0.63 0.22
Total seagrass No detectable trend 2016 - 2025 69.86 -0.41 0.45

Total SAV, total seagrass, shoal grass, and turtle grass showed no detectable change in percent cover. Trends in percent cover could not be evaluated for manatee grass and widgeon grass due to insufficient data.

Map showing SAV sampling sites within the boundaries of Fort Pickens State Park Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Fort Pickens State Park Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Gasparilla Sound-Charlotte Harbor Aquatic Preserve

SAV LME Results for Gasparilla Sound-Charlotte Harbor Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Attached algae No detectable trend 2007 - 2024 -11.38 0.91 0.26
Drift algae No detectable trend 1999 - 2024 8.35 0.37 0.18
Shoal grass No detectable trend 1998 - 2024 20.79 -0.12 0.08
Star grass Insufficient data - - - -
Widgeon grass No detectable trend 1998 - 2019 4.26 -0.04 0.80
Manatee grass No detectable trend 1998 - 2024 46.72 -0.26 0.62
Turtle grass No detectable trend 1998 - 2024 32.49 -0.22 0.14
Total seagrass Decreasing trend 1998 - 2024 25.25 -0.20 0.01

An annual decrease in percent cover was observed for total seagrass (-0.20%). Manatee grass, shoal grass, turtle grass, widgeon grass, attached algae, and drift algae showed no detectable change in percent cover. Trends in percent cover could not be evaluated for star grass due to insufficient data.

Map showing SAV sampling sites within the boundaries of Gasparilla Sound-Charlotte Harbor Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Gasparilla Sound-Charlotte Harbor Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Indian River-Malabar to Vero Beach Aquatic Preserve

SAV LME Results for Indian River-Malabar to Vero Beach Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae Insufficient data - - - -
Shoal grass Model did not fit the available data - - - -
Halophila spp. No detectable trend 1997 - 2025 0.49 0.00 0.79
Widgeon grass No detectable trend 1997 - 2025 0.24 -0.01 0.10
Manatee grass Decreasing trend 1997 - 2025 5.52 -0.23 0.00
Turtle grass No detectable trend 1997 - 2025 1.73 -0.07 0.10
Total SAV Decreasing trend 1994 - 2025 39.51 -1.47 0.00
Total seagrass Insufficient data - - - -

Annual decreases in percent cover were observed for total SAV (-1.47%) and manatee grass (-0.23%). Halophila spp., turtle grass, and widgeon grass showed no detectable change in percent cover. Trends in percent cover could not be evaluated for total seagrass and drift algae due to insufficient data, and the model could not be fitted for shoal grass.

Map showing SAV sampling sites within the boundaries of Indian River-Malabar to Vero Beach Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Indian River-Malabar to Vero Beach Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Indian River-Vero Beach to Ft. Pierce Aquatic Preserve

SAV LME Results for Indian River-Vero Beach to Ft. Pierce Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae Insufficient data - - - -
Shoal grass Decreasing trend 1998 - 2025 27.88 -0.78 0.00
Halophila spp. No detectable trend 1998 - 2025 0.12 0.01 0.09
Widgeon grass No detectable trend 1998 - 2025 0.13 0.00 0.12
Manatee grass Decreasing trend 1998 - 2025 15.48 -0.55 0.04
Turtle grass Decreasing trend 1998 - 2025 5.65 -0.19 0.01
Total SAV Decreasing trend 1994 - 2025 51.26 -1.60 0.00
Total seagrass Insufficient data - - - -

Annual decreases in percent cover were observed for total SAV (-1.60%), manatee grass (-0.55%), shoal grass (-0.78%), and turtle grass (-0.19%). No detectable change in percent cover was observed for Halophila spp. and widgeon grass. Trends in percent cover could not be evaluated for total seagrass and drift algae due to insufficient data.

Map showing SAV sampling sites within the boundaries of Indian River-Vero Beach to Ft. Pierce Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Indian River-Vero Beach to Ft. Pierce Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Jensen Beach to Jupiter Inlet Aquatic Preserve

SAV LME Results for Jensen Beach to Jupiter Inlet Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae Insufficient data - - - -
Shoal grass No detectable trend 1997 - 2025 8.41 -0.15 0.10
Halophila spp. No detectable trend 1997 - 2025 1.66 -0.03 0.06
Widgeon grass Model did not fit the available data - - - -
Manatee grass Decreasing trend 1997 - 2025 16.27 -0.56 0.00
Turtle grass No detectable trend 1997 - 2025 3.16 -0.09 0.07
Total SAV Decreasing trend 1994 - 2025 30.00 -0.77 0.00
Total seagrass Insufficient data - - - -

Annual decreases in percent cover were observed for total SAV (-0.77%) and manatee grass (-0.56%). Halophila spp., shoal grass, and turtle grass showed no detectable change in percent cover. Trends in percent cover could not be evaluated for total seagrass and drift algae due to insufficient data, and the model could not be fitted for widgeon grass.

Map showing SAV sampling sites within the boundaries of Jensen Beach to Jupiter Inlet Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Jensen Beach to Jupiter Inlet Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Lemon Bay Aquatic Preserve

SAV LME Results for Lemon Bay Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Attached algae No detectable trend 1999 - 2024 -1.17 0.47 0.26
Drift algae Decreasing trend 1999 - 2024 22.53 -0.54 0.02
Shoal grass No detectable trend 1998 - 2024 28.69 0.19 0.60
Manatee grass No detectable trend 1998 - 2024 6.78 -0.01 0.96
Turtle grass No detectable trend 1998 - 2024 4.32 0.30 0.45
Total seagrass No detectable trend 1998 - 2024 26.64 0.55 0.25

An annual decrease in percent cover was observed for drift algae (-0.54%). Total seagrass, manatee grass, shoal grass, turtle grass, and attached algae showed no detectable change in percent cover.

Map showing SAV sampling sites within the boundaries of Lemon Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Lemon Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Lignumvitae Key Aquatic Preserve

Not enough data to perform analyses in Lignumvitae Key Aquatic Preserve

Loxahatchee River-Lake Worth Creek Aquatic Preserve

SAV LME Results for Loxahatchee River-Lake Worth Creek Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae Insufficient data - - - -
Shoal grass Decreasing trend 1999 - 2025 20.20 -0.58 0.00
Halophila spp. Decreasing trend 1999 - 2025 1.71 -0.04 0.00
Widgeon grass Model did not fit the available data - - - -
Manatee grass No detectable trend 1999 - 2025 2.54 -0.08 0.34
Turtle grass No detectable trend 1999 - 2025 0.09 0.00 0.30
Total SAV Decreasing trend 1999 - 2025 27.66 -0.80 0.00
Total seagrass Insufficient data - - - -

Annual decreases in percent cover were observed for total SAV (-0.80%), Halophila spp. (-0.04%), and shoal grass (-0.58%). No detectable change in percent cover was observed for manatee grass and turtle grass. Trends in percent cover could not be evaluated for total seagrass and drift algae due to insufficient data, and the model could not be fitted for widgeon grass.

Map showing SAV sampling sites within the boundaries of Loxahatchee River-Lake Worth Creek Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Loxahatchee River-Lake Worth Creek Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Matlacha Pass Aquatic Preserve

SAV LME Results for Matlacha Pass Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Attached algae Insufficient data - - - -
Drift algae No detectable trend 2000 - 2024 -5.87 1.10 0.10
Shoal grass No detectable trend 2000 - 2024 19.63 0.08 0.88
Paddle grass Insufficient data - - - -
Star grass No detectable trend 2010 - 2023 2.64 0.07 0.78
Widgeon grass Insufficient data - - - -
Manatee grass Insufficient data - - - -
Turtle grass No detectable trend 2000 - 2024 26.60 -0.48 0.16
Total seagrass No detectable trend 2002 - 2024 33.45 -0.53 0.13
Halophila, unk. Insufficient data - - - -

Total seagrass, shoal grass, star grass, turtle grass, and drift algae showed no detectable change in percent cover. Trends in percent cover could not be evaluated for unknown Halophila, manatee grass, paddle grass, widgeon grass, and attached algae due to insufficient data.

Map showing SAV sampling sites within the boundaries of Matlacha Pass Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Matlacha Pass Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Mosquito Lagoon Aquatic Preserve

SAV LME Results for Mosquito Lagoon Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae Insufficient data - - - -
Shoal grass No detectable trend 2009 - 2025 3.71 0.21 0.24
Halophila spp. No detectable trend 2009 - 2025 -0.05 0.00 0.16
Widgeon grass Model did not fit the available data - - - -
Manatee grass Model did not fit the available data - - - -
Turtle grass Model did not fit the available data - - - -
Total SAV No detectable trend 2009 - 2025 3.67 0.21 0.24
Total seagrass Insufficient data - - - -

Total SAV, Halophila spp., and shoal grass showed no detectable change in percent cover. Trends in percent cover could not be evaluated for total seagrass and drift algae due to insufficient data, and a model could not be fitted for manatee grass, turtle grass, and widgeon grass.

Map showing SAV sampling sites within the boundaries of Mosquito Lagoon Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Mosquito Lagoon Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Nature Coast Aquatic Preserve

SAV LME Results for Nature Coast Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae No detectable trend 1997 - 2025 18.46 -0.32 0.43
Shoal grass Decreasing trend 1997 - 2025 14.44 -0.17 0.04
Star grass No detectable trend 1997 - 2025 8.79 0.09 0.39
Widgeon grass No detectable trend 1997 - 2025 8.39 0.04 0.97
Manatee grass Decreasing trend 1997 - 2025 57.52 -1.51 0.00
Turtle grass Decreasing trend 1997 - 2025 113.70 -2.77 0.00

Annual decreases in percent cover were observed for manatee grass (-1.51%), shoal grass (-0.17%), and turtle grass (-2.77%). Star grass, widgeon grass, and drift algae showed no detectable change in percent cover.

Map showing SAV sampling sites within the boundaries of Nature Coast Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Nature Coast Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Pine Island Sound Aquatic Preserve

SAV LME Results for Pine Island Sound Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Attached algae No detectable trend 2002 - 2023 18.49 -0.57 0.07
Drift algae No detectable trend 2000 - 2024 12.13 -0.01 0.93
Shoal grass No detectable trend 2000 - 2024 15.44 0.43 0.22
Paddle grass Insufficient data - - - -
Star grass Insufficient data - - - -
Widgeon grass Insufficient data - - - -
Manatee grass No detectable trend 2000 - 2024 20.59 0.37 0.28
Turtle grass No detectable trend 1998 - 2024 8.91 0.11 0.46
Total seagrass No detectable trend 1998 - 2024 19.27 0.30 0.33

Total seagrass, manatee grass, shoal grass, turtle grass, attached algae, and drift algae showed no detectable change in percent cover. Trends in percent cover could not be evaluated for paddle grass, star grass, and widgeon grass due to insufficient data.

Map showing SAV sampling sites within the boundaries of Pine Island Sound Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Pine Island Sound Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Pinellas County Aquatic Preserve

SAV LME Results for Pinellas County Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Attached algae No detectable trend 2000 - 2021 1.35 -0.01 0.96
Drift algae Increasing trend 2012 - 2025 -49.76 2.67 0.00
Shoal grass No detectable trend 1998 - 2025 23.58 0.21 0.15
Star grass Insufficient data - - - -
Widgeon grass No detectable trend 1998 - 2024 -20.72 1.16 0.37
Manatee grass No detectable trend 1998 - 2025 19.93 0.33 0.11
Turtle grass No detectable trend 1998 - 2025 42.22 -0.21 0.20
Total SAV No detectable trend 2011 - 2019 35.61 0.42 0.57
Halophila, unk. No detectable trend 1999 - 2022 -1.64 0.11 0.66

An annual increase in percent cover was observed for drift algae (2.67%). Total SAV, unknown Halophila, manatee grass, shoal grass, turtle grass, widgeon grass, and attached algae showed no detectable change in percent cover. Trends in percent cover could not be evaluated for star grass due to insufficient data.

Map showing SAV sampling sites within the boundaries of Pinellas County Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Pinellas County Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Rookery Bay Aquatic Preserve

SAV LME Results for Rookery Bay Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Shoal grass No detectable trend 1998 - 2005 33.63 -1.71 0.25
Paddle grass No detectable trend 1998 - 2005 -0.44 0.08 0.36
Star grass No detectable trend 1998 - 2005 3.53 -0.23 0.44
Manatee grass No detectable trend 1998 - 2005 16.10 -1.13 0.40
Turtle grass No detectable trend 1998 - 2005 36.99 -3.14 0.07
Total seagrass Decreasing trend 1998 - 2005 68.37 -4.52 0.02

An annual decrease in percent cover was observed for total seagrass (-4.52%). Manatee grass, paddle grass, shoal grass, star grass, and turtle grass showed no detectable change in percent cover.

Map showing SAV sampling sites within the boundaries of Rookery Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Rookery Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Rookery Bay National Estuarine Research Reserve

SAV LME Results for Rookery Bay National Estuarine Research Reserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Shoal grass No detectable trend 1998 - 2005 33.63 -1.71 0.25
Paddle grass No detectable trend 1998 - 2005 -0.44 0.08 0.36
Star grass No detectable trend 1998 - 2005 3.53 -0.23 0.44
Manatee grass No detectable trend 1998 - 2005 16.10 -1.13 0.40
Turtle grass No detectable trend 1998 - 2005 36.99 -3.14 0.07
Total seagrass Decreasing trend 1998 - 2005 68.37 -4.52 0.02

An annual decrease in percent cover was observed for total seagrass (-4.52%). Manatee grass, paddle grass, shoal grass, star grass, and turtle grass showed no detectable change in percent cover.

Map showing SAV sampling sites within the boundaries of Rookery Bay National Estuarine Research Reserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Rookery Bay National Estuarine Research Reserve. The point size reflects the number of samples at a given sampling site.

St. Andrews Aquatic Preserve

SAV LME Results for St. Andrews Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae No detectable trend 2016 - 2023 84.42 -2.62 0.07
Shoal grass No detectable trend 2000 - 2023 11.99 0.27 0.49
Manatee grass No detectable trend 2000 - 2023 4.17 -0.15 0.82
Turtle grass No detectable trend 2000 - 2023 27.04 1.06 0.13
Total seagrass No detectable trend 2000 - 2007 88.14 -1.52 0.15

Total seagrass, manatee grass, shoal grass, turtle grass, and drift algae showed no detectable change in percent cover.

Map showing SAV sampling sites within the boundaries of St. Andrews Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of St. Andrews Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

St. Joseph Bay Aquatic Preserve

SAV LME Results for St. Joseph Bay Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae No detectable trend 2006 - 2023 9.61 0.08 0.83
Shoal grass No detectable trend 2005 - 2023 48.45 -0.49 0.50
Manatee grass No detectable trend 2005 - 2023 54.20 -0.90 0.26
Turtle grass No detectable trend 2005 - 2023 62.38 -0.14 0.69

Manatee grass, shoal grass, turtle grass, and drift algae showed no detectable change in percent cover.

Map showing SAV sampling sites within the boundaries of St. Joseph Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of St. Joseph Bay Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

St. Martins Marsh Aquatic Preserve

SAV LME Results for St. Martins Marsh Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae No detectable trend 1997 - 2025 18.42 -0.22 0.10
Shoal grass No detectable trend 1997 - 2025 27.14 -0.26 0.14
Star grass Decreasing trend 1997 - 2025 75.14 -2.16 0.04
Widgeon grass No detectable trend 1997 - 2025 23.54 -0.16 0.66
Manatee grass No detectable trend 1997 - 2025 18.49 -0.13 0.51
Turtle grass No detectable trend 1997 - 2025 36.16 -0.18 0.25

An annual decrease in percent cover was observed for star grass (-2.16%). Manatee grass, shoal grass, turtle grass, widgeon grass, and drift algae showed no detectable change in percent cover.

Map showing SAV sampling sites within the boundaries of St. Martins Marsh Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of St. Martins Marsh Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Terra Ceia Aquatic Preserve

SAV LME Results for Terra Ceia Aquatic Preserve
Species Statistical Trend Period of Record LME Intercept LME Slope p
Drift algae Insufficient data - - - -
Shoal grass Increasing trend 1999 - 2024 25.74 0.86 0.00
Widgeon grass Insufficient data - - - -
Manatee grass No detectable trend 1999 - 2023 36.54 0.14 0.71
Turtle grass No detectable trend 1999 - 2024 34.43 0.23 0.45
Halophila, unk. Insufficient data - - - -

An annual increase in percent cover was observed for shoal grass (0.86%). No detectable change in percent cover was observed for manatee grass and turtle grass. Trends in percent cover could not be evaluated for unknown Halophila, widgeon grass, and drift algae due to insufficient data.

Map showing SAV sampling sites within the boundaries of Terra Ceia Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Terra Ceia Aquatic Preserve. The point size reflects the number of samples at a given sampling site.

Summary of SEACAR_SAV_BB_script_website.R

  • Objective: Import and format SAV data, create summary plots and maps of changes over time, model changes over time using Bayesian and mixed-effects models. Results are separate for each managed area, species, and parameter (e.g., Braun Blanquet, percent cover, etc.).
  • Packages: bayesplot, brms, broom.mixed, data.table, grid, gridExtra, gtable, nlme, scales, sf, tictoc, tidybayes, tidyverse
  • File inputs: All_SAV_Parameters-2024-Sep-19.txt, seacar_dbo_SampleLocation_Point.shp, seacar_dbo_SampleLocation_Line.shp, ORCP_Managed_Areas.shp, Counties_-_Detailed_Shoreline.shp, MApolygons_corners.csv
  • Steps by line number:
    • 1 - 40: load libraries and import SAV file, create necessary sub-folders.
    • 43 - 132: format SAV data including renaming columns, removing NA values, and reformatting abundance/cover values. For the latter, this included removal of NA values and those out of range, and ensuring appropriate values for Braun Blanquet, modified Braun Blaunqet, percent occurrence, and percent cover.
    • 136: Import ManagedArea.csv to obtain abbreviated ManagedAreaNames.
    • 139 - 193: function for plotting model predictions (multiplots).
    • 196 - 288: function for plotting model predictions with simplified trendlines on a single plot (trendplots).
    • 292 - 307: function used throughout script to allow for swift modification of species labels between “common” and “scientific” names. The script defaults to using scientific throughout the backend (i.e. .rds objects with species names default to scientific), with the usenames variable (line 468) converting the display of species names to the desired display type.
    • 310: EDA variable to specify what the script should produce. Setting to “plots” creates data exploration plots.
    • 313: scope_plots variable can be set to TRUE or FALSE. Set to TRUE to render spatio-temporal scope plots for each ManagedArea. Resulting plots are placed in the ‘output/Figures/SAV_temporal_scope_plots/’ folder.
    • 323 - 324: create failedmods data table to store failed model results.
    • 327 - 499: setup parameter list and objects for looping through parameters to create models and summary output, parameters include Braun Blanquet, median percent cover, visual percent cover, percent occurrence, frequency of occurrence. Write results to output .xlsx files.
      • 351 - 395: setting up palettes for both species (spcols) and ProgramNames (prcols).
    • 517 - 1192: loop through parameters to create models and summary output, the following is an outline of steps in this loop.
      • 530 - 1518: loop through managed areas using parameter from outside loop
      • 539 - 553: create and save plot of parameter score for managed area over time by species
      • 555 - 568: create and save plot of parameter score for managed area over time by program ID
      • 570 - 583: create and save plot of parameter score for managed area over time grouped by species, by program ID
      • 585 - 598: create and save plot of quadrat sizes for managed area over time by species
      • 600 - 613: create and save plot of quadrat sizes for managed area over time by program ID
      • 615 - 628: create and save plot of method for managed area over time by species
      • 630 - 643: create and save plot of method for managed area over time by program ID
      • 645 - 659: create and save plot of method for managed area by quadrat size and species
      • 661 - 675: create and save plot of method for managed area by quadrat size and program ID
      • 677 - 707: create and save plots of grid values over time by species and program ID if data available
      • 709 - 739: create and save plots of depth values over time by species and program ID if data available
      • 743 - 759: create and save a plot legend of species
      • 762 - 785: loop through species to create and save a plot of parameter score over time
      • 787 - 808: create and save a plot of totals for the species of parameter score over time
      • 811 - 827: create and save a plot legend of species
      • 830 - 853: loop through species to create and save a plot of parameter score as boxplots over time
      • 855 - 875: create and save a plot of boxplots for the species of parameter score over time
      • 898 - 908: setup empty objects for model results
      • 912 - 1029: Loop through species to fit models, with separate exception statements for different parameters. The modeling workflow is similar for each parameter, with minor exceptions. The general goal of each is to assess trends in a parameter over time for a particular species and managed area. Each workflow includes error handling if models did not converge, produces summary tables of model fit, and summary plots showing model result. The models vary in the Gaussian distribution family for the response variable depending on parameter. Random effects (e.g., for LocationID) are used for all models.
      • 1033 - 1124: create base plot of seagrass percent cover data over time for managed area. Add model fits if applicable, and saves object
        • 1036 - 1046: reads and sets modeled data for plots
      • 1127 - 1185: create and save barplots of parameter results for managed area over time by species, only for Braun Blanquet and percent cover, save model results from prior loops
      • 1197 - 1265: export .png of all plot types, setting height dynamically for multiplots.
      • 1273 - 1277: zip all images into subfolders and create SAV_Figures_[usenames].zip where usenames is either “scientific” or “common” based on the usenames variable setting.