**A Final Report of the**

**Vegetation Survey and Map Project for**

**St. Vincent National Wildlife Refuge, Apalachicola, Florida**

**A USFWS-USGS Research Partnership Program Project**

**submitted by**

**Susan L. Grace**

**U.S. Geological Survey**

**National Wetlands Research Center**

**700 Cajundome Blvd.**

**Lafayette, LA**

**70506**

**phone: 337-266-8618**

**e-mail: sue_grace@usgs.gov**

**April 2000**

**Contents**

Initial Project Description 4

Brief Project Summary 4

Background 5

Climate 5

Geology 6

Soils 7

Hydrology 14

Natural Disturbances 15

Hurricanes 15

Wildfires and Prescribed Fires 16

Methods 18

Earlier Vegetation Surveys 18

Field Survey Procedures 1997 19

Mapping Procedures 19

Results 20

Plant Database 20

Species at Risk 20

Invasive Species 21

Vegetation Map 23

Vegetation Class Descriptions 24

Pine Flatwoods 24

Pine-Cabbage Palm Flatwoods 28

Cabbage Palm Hammock 31

Scrub 34

Sand Pine-Scrub 37

Live Oak Hammock 40

Hardwood Hammock 43

Coastal Grassland 46

Palustrine Marsh 49

Palustrine Shrub 53

Palustrine Open Water 56

Estuarine Marsh 59

Estuarine Shrub 62

Estuarine Open Water 64

Beach Dunes 67

Other Cover Classes 70

Intertidal Zone 70

Oyster Reef 70

Intertidal Flats 70

Developed 71

Managed Marsh 72

Managed Open Water 73

Summary 73

Research Needs 74

Acknowledgments 74

Literature Cited 76

Appendix 78

**Initial Project Description**

In an effort to understand the plant community structure of St. Vincent
Island, the US Fish and Wildlife Service (USFWS) conducted a vegetation
survey of the island in 1969. At that time, 17 plant communities were
identified and mapped using colored pencils and hand-drawn delineations
of vegetation boundaries. This map was in desperate need of updating
using current knowledge of plant community classifications and
technologies. The objectives of this research were to resurvey the plant
communities on the refuge and to create a digitized vegetation map to be
used as a tool for management decisions for USFWS staff. This map,
developed as a GIS layer, would provide needed information used in the
management of wildlife, fire, hydrology, and recreation areas for which
the refuge currently is responsible.

Refuge employees were responsible for information associated with the
1969 vegetation survey, current road maps of St. Vincent NWR, and site
visit consultations. An estimated 5-15 person days of refuge employee
time was required to conduct these activities. U.S. Geological Survey,
Biological Resources Division (USGS-BRD) personnel and associates were
responsible for photo interpretation and digitizing of photography, a
new vegetation survey, and delineations of vegetation boundaries.
Discussions with researchers from the National Wetlands Research Center
(NWRC) in Lafayette, Louisiana, indicated that the direct costs could be
minimized by the fact that employee time would be donated by each
agency. USGS-BRD would contribute partial funding towards the vegetation
survey and photo interpretation (supervised by Dr. Sue Grace, NWRC).
Total estimated costs for this project included the cost of updating the
aerial photography and a student intern to help digitize information
from the photography. Project completion: December 1999.

**Brief Project Summary**

In July 1997, Thom Lewis, biologist at St. Vincent National Wildlife
Refuge (NWR) identified a research need to have the vegetation of the
refuge surveyed and mapped for management purposes. USGS staff made an
initial refuge visit in October 1997 where ideas and issues were
discussed among collaborative staff to help define a study to meet the
research needs requested by the refuge. In the fall 1997, a proposal for
the Research Partnership Program was successfully funded to support the
identified projects and further support was provided from the USFWS
Ecological Services Office, Panama City, FL.

Information regarding aerial photography acquisition, earlier plant
surveys and vegetation maps, soil maps, and ecological literature was
obtained during the fall 1997. Also at this time correspondence was
established between collaborators and Anne Johnson of the Florida
Natural Areas Inventory (FNAI) with a site visit in October 1997.

Field surveys were conducted during the next two summers (FY 1998-99) to
define and refine plant communities used in the vegetation map. A draft
vegetation map was completed by the end of summer 1998, then
ground-truthed, georeferenced, and refined in summer 1999. In addition
to definition of plant community boundaries, a description of each plant
community was made and dominant plant species listed for each plant
community type. Plant community descriptions were made and cross
referenced to earlier vegetation descriptions of the refuge and compared
to the natural community descriptions for Florida published by FNAI
(1990).

Products from this project included an updated list of plant species for
the refuge, a plant database describing plant species on the refuge, a
description of plant communities, and a final map of the vegetation
types of the refuge both in digital and hard copy. This project is an
excellent working example of interagency cooperation between USFWS and
USGS. The help of the USFWS staff made this project possible by
providing transportation to and from the refuge, housing, fuel and
transportation while on the refuge and in sharing their knowledge,
providing historical data and information of the refuge itself.

**Background**

St. Vincent National Wildlife Refuge (NWR) is made up of three land
units: (1) St. Vincent Island - a 12,35-acre island located in a chain
of barrier islands within Apalachicola Bay; (2) the mainland unit, an
86-acre pine forest and tidal marsh located on the adjacent mainland
across from St. Vincent Island; (3) Pig Island, a small 46 acre island
located to the east of St. Joseph Peninsula within St. Joseph Bay. Both
the St. Vincent Island and mainland unit boundaries are within Franklin
County. Pig Island is located in Gulf County.

**Climate**

The climate of the Apalachicola area is affected by the adjacent Gulf of
Mexico and is characterized as a moderate climate with long, warm
growing seasons and mild winters (Sasser et al. 1994). Average summer
temperatures for June, July, and August hover around 80^0^F while winter
temperatures for December, January, and February fall to 55^0^F. The
last freeze date for spring is February 2, and the first freeze date in
fall is December 21 giving a 322 day potential growing season for the
area. Precipitation in the Apalachicola area follows two rain periods.
The summer rainy season from June through September contributes an
average of 30 inches of rain a year while the winter rainy season
(December through April) contributes an average of 16 inches per year
with May, October, and November being generally drier months. Total
average precipitation is about 56 inches per year.

Summer at St. Vincent NWR is characterized by afternoon thunderstorms
caused by the moist, unstable air produced from the surrounding Gulf of
Mexico waters. Thunderstorms are generally intense and occur over a
short period of time during 2-4 days each week. In general, these
thunderstorms produce little significant rainfall but occasionally can
produce 2 to 3 inches of rain in less than 2 hours. The greatest amount
of precipitation recorded for the Apalachicola region was 11.7 inches in
September 1932. Humidity is high in this area as a result of the
adjacent Gulf of Mexico waters. The humidity will fall to 60% to 70%
during mid-afternoons of summer and recover to 85% during the night
until dawn.

The prevailing winds are from the north in the winter and south in the
summer with an average windspeed ranging from 6.5 to 7.9 mph. A record
windspeed of 85 miles per hour was recorded during Hurricane Kate,
November 1985.

**Geology**

The underlying geologic formation described for the Apalachicola region
includes Miocene, Pliocene, and Holocene descriptions although older
geologic formations certainly underlie these formations (Stapor 1973,
Sasser et al. 1994). The Miocene formations are found approximately
300-450 feet below mean sea level and include the St. Mark\'s Formation
(early Miocene in age - 26 million years ago) and the Bruce Creek
Limestone Formation (early to mid Miocene in age). Both formations are
mostly composed of limestone with some thin beds of sand and clay
present. The Intracoastal Formation (late Miocene to early Pliocene in
age - 13 million years ago), overlies the St. Mark\'s Formation and
Bruce Creek Limestone Formations and occurs up to 175 feet below mean
sea level in the vicinity of St. Vincent Island. Pliocene formations
that occur in this area and below the island includes the Alum Bluff
Group (late Pliocene in age - 2 million years ago), which is composed of
unconsolidated sandy, shelly limestone in a clay matrix and sandy shell
beds. More recent Pleistocene and Holocene deposits of undifferentiated
surface sediments (alluvium and marine terrace deposits), overlie the
Alum Bluff deposits and are less than 11,000 years old. These Holocene
deposits make up the surface geologic layers of St. Vincent Island and
surrounding area. The earliest radiocarbon dates from Holocene deposits
of the barrier islands are approximately 4,400 years old (Schnable
1966).

There has been significant study and interpretation of the geologic
history of St. Vincent Island and the geologic formation of the barrier
islands of Apalachicola Bay (Stapor 1973, Stapor and Tanner 1977,
Donohue et al. 1990). Stapor (1973) suggested that St. Vincent Island
was formed from a series of sand ridges that were deposited from the
northwest end of the island (the oldest ridges) to the southeast end of
the island (youngest sand ridges). The oldest sand ridges on the island
have been carbon dated to being between 3,500 and 6,500 years old.
Following the initial shoal development on the northwest portion of the
island a series of four east-west oriented sand ridges, less than 2
miles each, formed to the south of the shoal. Stapor also suggests a
possible sea-level rise approximately 2,000 to 3,000 years ago which
drowned the older ridges and created Big Bayou. Following this increase
in sea level, the sand ridge deposition forming St. Vincent Island
changed the orientation to a more southeast-northwest one. Also
following this sea-level rise St. George shoal developed, beaches of
Cape St. George Island formed and Pig Island formed as the beginning of
Cape San Blas shoal developed. These newly developed islands continued
to grow from sand ridge depositions 1,000 to 2,000 years ago. The
formation of the deep and narrow West Pass Channel between St. Vincent
Island and Cape St. George Island led to the formation of the youngest
sand ridges on the island which were deposited 400-500 years ago. As a
result of the deep West Pass channel formation, the youngest deposited
sand ridges have been deposited at more northeast-southwest orientation,
almost perpendicular to the orientation of the older sand ridges on the
island. Donohue et al. (1990) suggests that the youngest sand ridges on
the southeast portion of the island are currently undergoing erosional
processes because of less sand availability for deposition.

**Soils**

There are 16 soil types mapped for St. Vincent NWR, with some overlap
among the refuge units (Table 1): 14 soil types mapped for St. Vincent
Island, 3 soils mapped for the mainland unit and 6 mapped for Pig
Island. The following is a description of each soil type and a general
description of its mapped location on the refuge. All descriptions are
summarized from the soils surveys conducted in Franklin and Gulf
Counties (Sasser et al. 1994).

**Table 1.** List of soils and location on St. Vincent NWR. SVI= St.
Vincent Island, MU=mainland unit, PI=Pig Island.

  ------------------------------------------- --------- --------- ---------
  Soil Type                                   SVI       MU        PI

  *Beaches*                                   X                   

  *Bohicket-Tisonia complex*                  X                   

  *Corolla sand*                              X                   X

  *Corolla-Duckston complex*                                      X

  *Dirego-Bayvi complex*                      X                   X

  *Duckston sand*                             X         X         

  *Duckston-Bohicket-Corolla complex*         X                   

  *Duckston-Rutledge-Corolla complex*         X                   

  *Kershaw sand*                              X                   

  *Kureb-Corolla complex*                                         X

  *Leon sand*                                           X         

  *Lynn Haven sand*                                     X         

  *Mandarin fine sand*                        X                   

  *Maurepas muck*                             X                   

  *Newhan-Corolla complex*                    X                   

  *Ortega fine sand*                          X                   

  *Resota fine sand*                          X                   

  *Rutledge loamy fine sand*                  X                   
  ------------------------------------------- --------- --------- ---------

***Beach soils***

Beaches are deposits of loose, fine sand and shell fragments within the
high tide mark. These fragments and sand are susceptible to movement by
wind and tide. This soil type is of low fertility and low organic
content. This soil type occurs in a small portion of St. Vincent Island
and is restricted to the narrow strip of beach along the southern and
eastern portions of St. Vincent Island from Indian Pass Point to West
Pass Point and along most of the eastern portion of St. Vincent Island
up to Mallard Slough. There is a small area of beach at St. Vincent
Point on the island.

***Bohicket and Tisonia soils***

These soils are very poorly drained soils of nearly level (\<1% slope)
tidal and estuarine marshes. Bohicket soil has approximately 23 inches
of gray silty clay in its surface layer to 80 inches of black silty
clay. Tisonia soil profile has 4 inches of mucky peat in the surface
layer, over 22 inches of brown muck below the surface layer, 44 inches
of gray clay, and below this to a depth of 80 inches of sand and sandy
clay loam. The water table of this soil complex occurs at or above the
surface throughout the year and under tidal influence. The organic
content of Bohicket soil is low to moderate (5-25%) whereas Tisonia soil
has a high organic content (40-65%). Both soil types exhibit high
salinities and fertility. This soil type occurs abundantly in the tidal
marshes on the eastern portion of St. Vincent Island including Big
Bayou, Mallard Slough, Sheepshead Bayou, and the marshes of the
northwest portion of the island.

***Corolla sand***

This soil type is a somewhat poorly drained soil of nearly level to
gently sloping terrain (\<3% slope). It occurs on salt flats, small sand
dunes and in swales of large dunes. The surface layer is composed of 6
inches of light gray sand and below the surface to 80 inches is more
light gray sand. This soil type has a seasonally high water table at a
depth of 18 to 36 inches for 3 to 6 months per year. Flooding can occur
during coastal storms and hurricanes. This soil type has a low organic
content (0.5%) and low fertility. This soil type is moderately abundant
on St. Vincent Island. It occurs scattered throughout the island on some
interior dunes and makes up the predominant soil type of the high dunes
along the southern portion of the island. There is a small portion of
this soil type found in association with the cabbage palm islands of the
northwestern portion of the island at the mouth of Big Bayou. It also
makes up the sand dunes along the southwestern portion of Pig Island.

***Corolla-Duckston complex***

The soils of this complex range from very poorly drained to moderately
drained soils of nearly level to strongly sloping terrain. They occur on
low dune-like ridges along the coast, low ridges and rises in flatwoods,
and floodplains. See earlier descriptions for Corolla sand and Duckston
sand for soil profile characterizations. This soil complex makes up the
sandy dune areas of Pig Island, primarily located on the eastern portion
of the island.

***Dirego and Bayvi soils***

These are very poorly drained soils of nearly level (\<1% slope) tidal
and estuarine marshes. Generally this soil complex is made up of 50%
Dirego and 40% Bayvi soils. The surface soil of Dirego soil is brown
muck to 35 inches with a subsurface sand to 72 inches. The surface soil
of Bayvi soil is mucky sand to 8 inches and a subsurface layer of sand
to 80 inches. Both soil types have a water table at or above the surface
throughout the year and are tidally influenced. Dirego soils have a high
organic content (25-60%) whereas the Bayvi soil has a moderate organic
content (8-20%). Both soil types are of low fertility and have high
salinities. This soil type has a low occurrence on St. Vincent Island
and is found in the marshes to the north of Big Bayou, in the northwest
portion of St. Vincent Island. It also makes up the soils of the marshes
of the southern portion of Pig Island.

***Duckston sand***

This is a poorly drained soil on nearly level (0-2% slopes) terrain. It
occurs on level flats adjacent to coastal dunes and marshes in low
swales between dunes. The soil surface layer consists of gray sand 4
inches thick, and below the surface layer to 80 inches is more gray and
white sand. There is a high water table in this soil type to a depth of
12 inches throughout the year. The water table may fluctuate with tides.
This soil type can flood during storm events. There is a low organic
content (3%) and this soil has low fertility. This soil type occurs in
moderate abundance on St. Vincent Island. It is found in association
with pine-cabbage palm flatwoods and swales of the southern portion of
the island. On the southeast end of the island it occurs in pine-cabbage
palm flatwoods adjacent to wetlands associated with Oyster Pond and
pine-cabbage palm flatwoods associated with the high dunes along the
coast of West Pass point. There is one narrow strip of this soil type
associated with a pine-palmetto flatwoods area in the interior of the
island between Shell Road and G Road near Road 6. There is also a small
narrow strip of this soil type associated with pine-palmetto flatwoods
north of the scrub oak dune that runs along Road A between Road 1 and
Road 2. In addition, there is a small portion of this soil type
associated with the swales adjacent to the high dunes that run along the
southern coast of the island between Road 3 and Road 4. This soil type
can also be found in the pine-cabbage palm flatwoods and swales in the
northwest portion of the island on the western end of Road J along Dry
Bar. This soil type occurs abundantly in the mainland unit. It is found
in association with the pine flatwoods forest community of this unit and
makes up about 50-60% of the unit.

***Duckston-Bohicket-Corolla complex***

This complex is made up of very poorly to somewhat poorly drained soils
of nearly level terrain (0-2% slopes). This complex of soils occurs on
low ridges, flats and in narrow, elongated tidal marshes on barrier
islands. This complex is made up of 50% Duckston, 25% Bohicket and 15%
Corolla soils. Duckston occurs on very low ridges, on nearly level
flats, and in swales; Bohicket occurs in narrow, elongated marshes
between low dune ridges and Corolla soil occurs on low dune ridges. See
previous descriptions for characteristics of individual soil types. This
soil complex has moderate to high occurrence on St. Vincent Island. It
occurs predominately on the northern portion and a small amount in the
southeastern corner of the island. It is most closely associated with
the hardwood hammock communities of the island north of Road G. In
addition it is associated with the pine flatwoods forests on Dry Bar
along Road I and Road J. This soil complex is also associated with the
hardwood hammock communities, southeast of St. Vincent Creek Outlet.

***Duckston-Rutledge-Corolla complex***

This complex is made up of very poorly drained to somewhat poorly
drained soils of nearly level terrain (0-2% slopes). This complex occurs
on low ridges, flats and swales of barrier islands. This complex is made
up of 50% Duckston, 25% Rutledge and 25% Corolla soils. Rutledge soils
occur in low swales, Duckston in flats and Corolla in low ridges. See
previous descriptions for characteristics of individual soil types. The
majority (\>60%) of St. Vincent Island is made up of this soil complex.
It occurs predominantly in the southern and middle of the island with no
occurrence of this soil complex in the oldest part of the island in the
northwest corner (north of Mallard Slough). This complex is closely
associated with the pine flatwoods forest communities that are the
dominant vegetation class of the island.

***Kershaw sand***

This is an excessively drained soil of sloping to strongly sloping
(5-12%) terrain. It occurs on side slopes and tops of high sandy ridges.
The surface layer is composed of 5 inches of gray sand with brown fine
sand below to a depth of 80 inches. There is no water table within 80
inches of the soil surface. This soil has a low organic content (\<1%)
and low fertility. This soil type has a low occurrence on St. Vincent
Island and occurs on two sand ridges on the southeast corner of the
island. It occurs in association with live oak hammocks.

***Kureb-Corolla complex***

This soil complex is made up of excessively to moderately drained soils
that are found in nearly level to strongly sloping terrain. These soils
are found in sand dune ridges along the coast and in low rises in
flatwoods. The profile for both soils consists of sandy soil to 80
inches. Soils in this complex may have a seasonal high water table
between 18 and 60 inches from 1 to 6 months per year, with no seasonal
water table the rest of the year. This soil complex is found in the sand
dunes along the western portion of Pig Island.

***Leon sand***

This soil type is a poorly drained soil of nearly level terrain (0-2%
slope). It occurs in broad flatwoods and on small inclines or low ridges
in titi bogs. The surface layer is 8 inches of dark gray sand with brown
gray to brown sand below to 80 inches. This soil type has a seasonally
high water table at a depth of 6-12 inches 1 to 4 months per year. The
soil has low to moderate levels of organic matter (0.5-4%) and has low
fertility. This soil type is moderately abundant on the mainland unit.
It occurs along the northern edge of the unit, in association with the
pine flatwoods community of the unit.

***Lynn Haven sand***

This soil type is a poorly drained soil of nearly level terrain (0-2%
slopes). This soil type is found in broad, depressional areas of
flatwoods. The soil profile consists of a surface layer composed of 8
inches black sand with 14 inches below of dark gray sand. The subsoil to
80 inches is gray and brown sand. This soil type has a seasonal (late
winter and early spring) high water table within a depth of 12 inches of
the surface 4 to 6 months per year and a depth of 30 inches the rest of
the year. The organic content of the soil is moderate (0.2-4%) with low
fertility. This soil type occurs in low abundance only on the mainland
unit. It is primarily located along the east end of the unit and along a
small north-south section through the middle of the unit.

***Mandarin fine sand***

This soil type is somewhat poorly drained in nearly level soil (0-3%
slopes) of low coastal ridges and small inclines in flatwoods. The
surface of this soil type has 4 inches of gray fine sand and below this
layer to 80 inches is more fine sand. There is a seasonally high water
table present in this soil at a depth of 18 to 36 inches for 3 to 6
months per year. This soil has low organic content (\<3%) and low
fertility. This soil type has a low occurrence on St. Vincent Island.
There are two locations in the interior of the island where this soil
type is found. It occurs in two interior sand ridges that run along the
southern half of the island in association with scrub oak plant
communities.

***Maurepas muck***

This is a poorly drained, organic soil of nearly level (\<1% slope)
brackish marshes and swamps. The surface layer consists of 6 inches of
brown muck, and below that to a depth of 80 inches is brown muck. There
is a high water table in this soil that is 6 to 12 inches above the
surface throughout the year. The water table is tidally influenced. The
organic content and the fertility is high in this soil type. This soil
type occurs in moderate to high abundance on St. Vincent Island. It is
located in the southeastern portion of the island. This soil type is
closely associated with the fresh and brackish marshes adjacent to the
lakes and large ponds in the southeastern end of the island.

***Newhan-Corolla complex***

This soil complex is made up of excessively to somewhat poorly drained
soils of gently undulating to steep terrain (5-15% up to 30% slope).
This complex occurs in coastal dunes and swales. The Newhan soils occur
in high dunes and the Corolla soils are soils of low dunes and swales.
The Newhan soil surface has 1 inch of gray sand and has gray and white
sands below to 80 inches. The surface layer of the Corolla sand is made
up of 3 inches of dark gray sand with more gray sand below to 80 inches.
Newhan soils do not have a water table within 80 inches of the surface
whereas the Corolla soil has a seasonal water table at a depth of 18 to
36 inches 2 to 6 months per year (36 inches below surface the rest of
year). Both soils have low organic content (0.5%) and low fertility.
This soil type is in moderate abundance on St. Vincent Island and is
found in two locations on the island. It is found along the tip of
Indian Pass Point along the southwestern corner and also occurs around
West Pass Point along the southeastern portion of the island. This soil
type occurs in association with the high sand dunes of the island.

***Ortega fine sand***

This soil type is moderately well-drained and in nearly level to gentle
sloping terrain (0-5% slopes). It occurs on side slopes or in concave
areas of sandy uplands. The surface layer consists of 5 inches of
grayish brown fine sand and below this to 80 inches is more fine sand.
This soil type has a seasonally high water table located at a depth of
60 to 72 inches for 6 months per year. The organic content of this soil
is low (1-2%) and has low fertility. This soil type has a low occurrence
on St. Vincent Island and is restricted to a small portion of the
southeastern end of the island associated with live oak sand ridges.

***Resota fine sand***

This soil type is a moderately well-drained soil of nearly level or
gently sloping (0-5% slopes) terrain. It occurs in coastal ridges and
remnant sand dunes. The soil profile consists of a surface of 3 inches
of fine sand with more fine sand to 80 inches below. There is a
seasonally high water table at a depth of 40 to 60 inches 6 months per
year. This soil type has low organic content (\<1%) and has low
fertility. The majority of interior sand ridges that run
northwest-southeast across St. Vincent Island are made up of Resota fine
sand, giving this soil type a moderate to high occurrence on the island.
These sand ridges are mainly in the southwestern and south central
portions of the island and are associated with the scrub oak communities
of the interior of the island.

***Rutledge loamy fine sand***

This is a very poorly drained soil of nearly level terrain and
depressions (\<2% slope). The surface layer is composed of 5 inches of
black loamy fine sand with fine gray sand below the surface to 80
inches. There is a seasonally high water table present in this soil type
at a depth of 24 inches for 3 to 6 months per year. This soil type has a
high organic content in the surface layer and low throughout the rest of
the profile. This soil type also has a moderate level of fertility. It
has low to moderate occurrence on St. Vincent Island. It is found
primarily on the southern half of the island adjacent to the large ponds
and lakes of the southeastern section of the island. This soil type
occurs in association with shrub thickets upstream from wetlands
adjacent to lakes 1, 4, and 5, Oyster Pond, and the sawgrass wetland
south of Road B between Road 3 and Road 4. It also occurs in a narrow
strip just south of Mallard Slough and is associated with a sawgrass
marsh.

**Hydrology**

The patterns of water movement, both at the surface and below, play a
significant role in the present day vegetation patterns observed on St.
Vincent NWR. Of the three units that make up the refuge, only surface
water flow movement on St. Vincent Island has been investigated. In a
recent study, Davis and Mokray (1999) documented sites where natural
flow of surface water of St. Vincent Island had been altered by road
construction and other modifications to determine how to restore natural
surface water flow patterns on the island. They observed water flow
patterns at 261 sites and determined that 250 sites exhibited channel
flow (surface flow from uplands to creek channels) and 11 sites
demonstrated sheet flow (large flat areas several hundred feet across
through which water flows in a large mass). All surface water flow on
the island results as run-off from rain events or occurs as baseflow
from seepage of the ground water table (estimated to be five ft above
mean sea level; Davis and Mokray 1999). The ground water table recharges
rapidly on the island because of the high sand content of the soil that
allows water to permeate down to the ground water table quickly.

Results of the recent hydrology study on St. Vincent Island suggest that
human alterations such as roads have created impediments to natural
surface water flow. Roads and other constructed features act as dams to
creeks, reduce flow to wetlands creating deeper water wetlands, reduce
salinity flows to salt marshes, provide a means of allowing nearby
creeks to overflow into one another during high water events, and
manipulate water movement with ditching. Not only have these activities
altered the natural surface water flow patterns, but they have also
significantly altered vegetation patterns as well. The most obvious
vegetation response to surface water flow changes can be seen along
roads where saltwater has been restricted to flow into creeks and
marshes on one side of the road. As a result, one side of the road shows
a converted saltwater marsh to freshwater marsh, and on the other side
the natural salt marsh is present. Roads have also created deeper water
wetlands on portions of the island, damming small creeks and channels.
As a result, more deeper-water plant species such as cattails, red
maple, and cypress trees have begun to invade willow thickets, bayheads
and titi swamps along the small creeks and channels. Having deeper-water
wetlands also affects the potential for a wetland to burn in dry
periods. Many of these wetland communities that are being converted
(e.g., titi swamps and bayheads), will not burn in dry periods
perpetuating less fire-tolerant species and greater abundance of deeper
water wetland species. In addition, water flow patterns on the island
are manipulated by water control structures constructed between lakes on
the southeastern portion of the island. These control devices have been
established to control water levels. They are currently used to manage
plant species, primarily cattails, and have a significant impact on the
composition of other wetland species present. Further, the construction
area of water control structures house several invasive species as a
result of soil disturbance. Further construction of culverts and other
water flow control structures should consider the possibility of
increasing introductions of invasive species Minimum soil disturbance
should be maintained in the construction of these modifications.

**Natural Disturbances**

The vegetation of St. Vincent NWR is subject to both large and small
scale disturbances that have influenced and continue to influence the
structure and abundance of plant species present on the refuge. Below is
a discussion of the two large scale disturbances that have significant
effects on the vegetation of St. Vincent NWR.

***Hurricanes***

One of the most significant large scale disturbances to the refuge
vegetation is hurricanes. Although the refuge is situated in an area
along the northern Gulf of Mexico that is considered to have a
relatively low frequency of hurricanes (Doyle and Krauss 1999), there
have been at least 60 tropical storm tracks through the general vicinity
of the refuge in the past 100 years. Of these storms, there have been 19
storms with hurricane force winds over 70 mph and two storms with winds
greater than 100 mph (Table 2). These storms play a strong role in the
dynamic vegetation patterns of the refuge over time. Sand is blown about
from the high winds of the storm and either covers up existing
vegetation or creates new sand dunes that allow a site for plants to
colonize. As a result, plant populations fluctuate in size and presence
over time. In addition to the impact of hurricanes on population loss or
gain, hurricanes also affect tree growth. Doyle and Krauss (1999) found
changes in diameter growth as a response to Hurricanes Elana and Kate in
1985. Trees impacted by the hurricane produced less girdle growth and
more foliage growth as a response. Doyle and Krauss (1999) also suggests
the hurricane of 1894 may have reduced forest density significantly as
evidenced by increased growth of neighboring trees resulting in a much
thinner stand of trees. In addition to affecting tree growth and forest
structure, hurricanes and strong wind and flood events can act as
mechanisms for new introductions of native and invasive plant species on
the refuge.

**Table 2.** Tropical storms with hurricane force winds (70 mph) for the
general vicinity of St. Vincent NWR.

+-------------------------------+--------------------------------------+
| Year of Hurricane             | Maximum                              |
|                               |                                      |
|                               | Windspeed                            |
|                               |                                      |
|                               | (mph)                                |
+-------------------------------+--------------------------------------+
| 1886                          | 96                                   |
+-------------------------------+--------------------------------------+
| 1886                          | 83                                   |
+-------------------------------+--------------------------------------+
| 1893                          | 81                                   |
+-------------------------------+--------------------------------------+
| 1894                          | 109                                  |
+-------------------------------+--------------------------------------+
| 1896                          | 75                                   |
+-------------------------------+--------------------------------------+
| 1899                          | 80                                   |
+-------------------------------+--------------------------------------+
| 1903                          | 79                                   |
+-------------------------------+--------------------------------------+
| 1915                          | 92                                   |
+-------------------------------+--------------------------------------+
| 1926                          | 73                                   |
+-------------------------------+--------------------------------------+
| 1929                          | 79                                   |
+-------------------------------+--------------------------------------+
| 1936                          | 83                                   |
+-------------------------------+--------------------------------------+
| 1939                          | 74                                   |
+-------------------------------+--------------------------------------+
| 1941                          | 83                                   |
+-------------------------------+--------------------------------------+
| 1966                          | 95                                   |
+-------------------------------+--------------------------------------+
| 1972                          | 80                                   |
+-------------------------------+--------------------------------------+
| 1985                          | 113                                  |
+-------------------------------+--------------------------------------+
| 1985                          | 97                                   |
+-------------------------------+--------------------------------------+
| 1995                          | 79                                   |
+-------------------------------+--------------------------------------+
| 1998                          | 74                                   |
+-------------------------------+--------------------------------------+

***Wildfires and Prescribed Fires***

A second large-scale disturbance that strongly influences the vegetation
of St. Vincent NWR is wildfires. Florida, in general, is prone to
wildfires because it is located in a climate that has the highest
frequency of lightning activity. As such, many of the native plant
communities are made up of plant species that are fire-tolerant and
benefit from fire by either resprouting or producing flowers and seeds
following fire. Although there is an active wildfire suppression program
on St. Vincent NWR and throughout the United States in all land
management agencies, there is a growing awareness of the importance of
wildfires on the landscape ecologically. In the last decade there have
been 24 wildfires that burned across 2,302 acres of the refuge (Table
3). We realize that fire is a critical process in many communities and
ecosystems in fire prone areas. As a result, we are increasing our fire
management programs to include prescribed fires that try to mimic
wildfire effects under more controlled conditions. St. Vincent NWR has a
fire management program that includes prescribed fires. In the last
decade over 113 prescribed burns have been conducted to successfully
burn 36,415 acres of the refuge (Table 3).

Fire is an important ecological process that determines the structure
and composition of natural plant communities of St. Vincent NWR.
Historically, wildfires occurred frequently on the landscape and were
caused by lightning strikes that ignited fuels to burn across the
landscape. The majority of refuge lands are dominated by slash pine
forests which is one of the forest types in the southeastern U.S. that
was naturally maintained by frequent low-intensity fires. Many of the
plant species of the pine forests of St. Vincent NWR are considered fire
tolerant or fire-adapted by having characteristics that allow the plant
to regenerate either vegetatively or reproductively following fire and
is not killed by fire. In the presence of frequent burning, the
structure of these forests develop into an open pine stand with little
to no midstory trees or shrubs present and a rich diverse layer of
grasses and herbs in the understory. The vegetation structure of these
forests are also influenced strongly by the season of burn. Robbins and
Myers (1990) have shown that frequent late spring and early summer fires
(growing season burns) will reduce woody shrub and tree invasion into
the forest. Further, less fire-tolerant, invasive plant species such as
Chinese tallow (*Sapium sebiferum*) may be eliminated with frequent
growing season burns (Grace 1998). On the other hand, in the absence of
fire (e.g., active fire suppression programs), heavier fuels such as
shrubs and small trees begin to invade forest stands and can have a
significant shading impact on native herbaceous vegetation in the
understory in as little as 3 years, thus significantly reducing native
plant diversity in a forest stand. As heavy fuels build up in fire
suppressed areas, the potential for higher intensity fire behavior can
be expected.

Not all plant communities on St. Vincent NWR should be subjected to
frequent burning however. Natural plant communities other than slash
pine forests such as scrub oak dunes, sand pine-scrub oak, scrub-shrub,
live oak hammocks, cabbage palm hammocks, and maritime forests probably
had less exposure to frequent fire because of the fuel structure in
these communities and probably only burned in extremely dry conditions.
As such, many of the plant species in these communities are not fire
tolerant and are killed back after each fire. A fire management program
for the refuge should consider the timing and season of burning in the
fire regime.

**Table 3.** Numbers of prescribed fire and wildfires from 1985-99 and
their acreages for St. Vincent NWR.

+---------------+------------+-------------+------------+------------+
| Year          | Number of  | Acreage of  | Number of  | Acreage of |
|               |            | Prescribed  | Wildfires  | wildfires  |
|               | Prescribed | Fire        |            |            |
|               |            |             |            | (acres)    |
|               | Fire       |             |            |            |
+---------------+------------+-------------+------------+------------+
| 1985          | 5          | 540         | 1          | 0.1        |
+---------------+------------+-------------+------------+------------+
| 1986          | 4          | 4960        | 0          | 0          |
+---------------+------------+-------------+------------+------------+
| 1987          | 6          | 843.4       | 1          | 0.3        |
+---------------+------------+-------------+------------+------------+
| 1988          | 6          | 1604.7      | 0          | 0          |
+---------------+------------+-------------+------------+------------+
| 1989          | 13         | 2246.8      | 1          | 33         |
+---------------+------------+-------------+------------+------------+
| 1990          | 9          | 1635        | 3          | 97         |
+---------------+------------+-------------+------------+------------+
| 1991          | 10         | 2336        | 2          | 201        |
+---------------+------------+-------------+------------+------------+
| 1992          | 8          | 2125        | 1          | 1100       |
+---------------+------------+-------------+------------+------------+
| 1993          | 16         | 5861        | 7          | 1452       |
+---------------+------------+-------------+------------+------------+
| 1994          | 9          | 2671        | 0          | 0          |
+---------------+------------+-------------+------------+------------+
| 1995          | 4          | 776         | 1          | 38         |
+---------------+------------+-------------+------------+------------+
| 1996          | 12         | 5045        | 0          | 0          |
+---------------+------------+-------------+------------+------------+
| 1997          | 1          | 151         | 1          | 86         |
+---------------+------------+-------------+------------+------------+
| 1998          | 10         | 5620        | 6          | 285        |
+---------------+------------+-------------+------------+------------+
| 1999          | 2          | 1278        | 4          | 160        |
+---------------+------------+-------------+------------+------------+
| Total         | 115        | 37692.9     | 28         | 3452.4     |
+---------------+------------+-------------+------------+------------+

**Methods**

**Earlier Vegetation Surveys**

St. Vincent Island is an attractive place for botanical surveys due to
its extensive diversity of native plants and plant communities. McAtee
(1913) published the first plant list for St. Vincent Island. There was
little plant inventory work following this survey for the next several
decades. Thompson (1970) conducted an extensive survey of vegetation
cover classes for St. Vincent Island and expanded the plant list
generated by McAtee (1913). Thompson listed 301 plant species that
occurred on St. Vincent Island. At this time, Thompson also completed a
plant community survey of Pig Island but did not submit a plant species
list. These surveys conducted by Thompson offered a baseline data for
general vegetation patterns for management operations of the refuge. The
results of Thompson\'s work is compared to current vegetation patterns
on the refuge in the Results section below. Thompson\'s existing plant
species list was expanded and 2 years on the barrier islands of the
Apalachicola National Estuarine Research Reserve including St. Vincent
Island. Results of this study showed 632 plant species listed for St.
Vincent Island (Anderson 1986, 1987, 1988). Additional research of plant
inventories and vegetation surveys have been conducted by FNAI in 1987
and are ongoing. These studies will inventory and monitor plant species
at risk on the refuge, specifically on St. Vincent Island (Table 4).

**Field Survey Procedures 1997**

The goal of the current study was to update vegetation data and produce
a digitized vegetation map. For the vegetation portion of this study,
the information gathering phase involved obtaining information regarding
previously published vegetation data. Information obtained included
published literature, maps, interim and final reports, and
correspondence and personal communications with previous surveyors. The
field phase of this project included an initial site visit for
reconnaissance, specimen collections, and initial descriptions of plant
communities. Additional site visits were conducted throughout the 2-year
period to continue to fine tune plant community descriptions and
inventory plant species. The product development phase of this research
included compiling all data resulting from plant inventories and
developing a plant database using Microsoft Access software.

**Mapping Procedures**

The mapping process consists of aerial photography acquisition, data
preparation, photo interpretation, and mapping. Procedures and
techniques used in the mapping process for this project were derived
from, and are in accordance with, nationally accepted standards and
conventions for map accuracy and habitat mapping. A photo search was
conducted to determine the availability of existing aerial photography.
Color infrared photography flown by NASA-Ames Research Center in
December 1992 at a scale of 1:32,500 was acquired for this project. This
data fulfilled the requirements necessary for landcover vegetation
mapping; namely, full stereo coverage, flown during leaf-off/winter time
of year, good quality, clarity and color, cloud-free coverage, and
acceptable scale for achieving level of detail desired for final map. In
preparation for photo interpretation, soil surveys, topographic maps,
and other collateral information was compiled and analyzed. A landcover
classification system was developed for the purpose of categorizing and
mapping the vegetation communities in accordance with project goals.
Field surveys were conducted to record ground-truthed data such as
habitat structure, vegetation type and/or class, and to correlate
photographic signatures for photo interpretation. The photography was
interpreted by using a stereoscope, and the vegetation classes were
delineated by hand with technical pen and ink. The data were mapped by
using a Zoom Transfer Scope. The cartographic transformation phase, as
this stage of the process is known, consists of transferring the
information from the aerial photograph to base maps, in this case, USGS
1:24,000 scale quadrangles. Field verification surveys as well as
quality control checks were conducted before final map production. The
maps were digitized and the data was edited, compiled, and stored in
ArcInfo format.

**Results**

**Plant Database**

The plant surveys of St. Vincent NWR during 1997 revealed eight new
plant species not previously reported for the refuge. These results
compiled with previous reports of plant surveys increase the total
number of plant species reported for the refuge to be 596 species. The
great number of plant species reported for the refuge reflects the vast
diversity of habitats included within the refuge boundaries. To manage
these data efficiently and effectively for current and future managers
of the refuge, a plant database was developed. This database includes
the following fields: common name, genus, species, variety or subspecies
(if present), author citation, plant family, flowering characteristics,
flowering date, life history (annual, biennial or perennial), habit
(herbaceous or woody), life form (herb, shrub, tree, vine), origin
(native or non-native), habitat, Florida status (common, frequent,
occasional, rare), wetland status (obligate wetland, facultative
wetland, facultative upland, obligate upland), species at risk (whether
it is monitored by FNAI as a rare plant), and global rank (as defined by
FNAI) for all plant species on the refuge. The software used to develop
this database allows for the user to sort by any field given above, so
refuge managers can access any part of the database needed to generate
lists of plants that are of interest.

***Species at Risk***

There are five known species at risk for St. Vincent NWR; corkwood
(*Leitneria floridana*), Gulf Coast lupine (*Lupinus westianus* var.
*westianus*), Florida beargrass (*Nolina atopocarpa*), West\'s flax
(*Linum westii*), and Drummond\'s yelloweyed grass (*Xyris drummondii*)
(Table 4). The Florida Natural Areas Inventory Program considers the two
most imperiled species on the refuge are the West\'s flax and the Gulf
Coast lupine which both have global ranks of G2 (imperiled globally). Of
these species, *Linum westii* is considered listed endangered by the
Florida Department of Agriculture and Consumer Services (FDACS). All
other species with the exception of *Xyris drummondii* are listed as
threatened species by the FDACS. There are no federally listed plant
species for the refuge currently.

**Table 4.** Species at risk listed for St. Vincent Island, both species
and common names are given as well as global rank, Florida status, and
federal status. Global and state ranks; G2=imperiled globally, G3=very
rare and local throughout range, S2=imperiled in Florida, S3= very rare
and local throughout range. Florida status ranks; LT=listed threatened,
LE= listed endangered, NL=not listed. There are no species listed that
are at risk federally.

+--------------------------+-------------------------+-------+--------+
| Species                  | Common Name             | G     | F      |
|                          |                         | lobal | lorida |
|                          |                         | Rank  |        |
|                          |                         |       | Status |
+--------------------------+-------------------------+-------+--------+
| *Leitneria floridana*    | corkwood                | G3S3  | LT     |
+--------------------------+-------------------------+-------+--------+
| *Linum westii*           | West\'s flax            | G2S2  | LE     |
+--------------------------+-------------------------+-------+--------+
| *Lupinus westianus* var. | Gulfcoast lupine        | G2S2  | LT     |
| *westianus*              |                         |       |        |
+--------------------------+-------------------------+-------+--------+
| *Nolina atopocarpa*      | Florida beargrass       | G3S3  | LT     |
+--------------------------+-------------------------+-------+--------+
| *Xyris drummondii*       | Drummond\'s yellow-eyed | G3S3  | NL     |
|                          | grass                   |       |        |
+--------------------------+-------------------------+-------+--------+

***Invasive Species***

There are 35 plant species listed for the refuge that are considered
invasive species to Florida (Wunderlin 1997). The invasive species of
the refuge represent 16 different plant families with grasses the
largest family represented by 10 species (Table 5). Most of the invasive
species introductions have occurred in human-altered sites within the
refuge, specifically on roadsides, water control structures and open
water canals. Some invasive species are introduced from high water
floodings into natural communities but there is little evidence of wide
establishment by this means of introduction. Current control management
practices for each species can be found on the internet at:
http://aquat1.ifas.ufl.edu/welcome.html (Center for Invasive and Aquatic
Species).

**Table 5.** A list of invasive plant species and their plant families
on St. Vincent NWR.

  --------------------------- -------------------------- ------------------
  Species                     Common Name                Family

  *Alternanthera              alligatorweed              Amaranthaceae
  philoxeroides*                                         

  *Carya illinoinensis*       pecan                      Juglandaceae

  *Carya ovata*               shagbark hickory           Juglandaceae

  *Chenopodium ambrosioides*  Mexican tea                Chenopodiaceae

  *Cynodon dactylon*          bermudagrass               Poaceae

  *Cyperus esculentus*        chufa flatsedge            Cyperaceae

  *Cyperus lanceolatus*       epiphytic flatsedge        Cyperaceae

  *Echinochloa crusgalli*     barnyardgrass              Poaceae

  *Eleusine indica*           Indian goosegrass          Poaceae

  *Eragrostis atrovirens*     thalia lovegrass           Poaceae

  *Heliotropium curassavicum* seaside heliotrope         Boraginaceae

  *Heliotropium indicum*      Indian heliotrope          Boraginaceae

  *Hyptis mutabilis*          tropical bushmint          Lamiaceae

  *Kummerowia striata*        Japanese clover            Fabaceae

  *Leonotis nepetifolia*      lion\'s ear                Lamiaceae

  *Limnophila sessiliflora*   Asian marshweed            Scrophulariaceae

  *Lycopersicon esculentum*   garden tomato              Solanaceae

  *Lygodium japonicum*        Japanese climbing fern     Schizaeaceae

  *Medicago lupulina*         black medick               Fabaceae

  *Mollugo verticillata*      green carpetweed           Molluginaceae

  *Panicum repens*            torpedograss               Poaceae

  *Paspalum notatum*          bahiagrass                 Poaceae

  *Paspalum urvillei*         vaseygrass                 Poaceae

  *Phyllostachys aurea*       golden bamboo              Poaceae

  *Polygonum lapathifolium*   pale smartweed             Polygonaceae

  *Rumex chrysocarpus*        amamastla                  Polygonaceae

  *Rumex paraguayensis*       Paraguayan dock            Polygonaceae

  *Sapium sebiferum*          Chinese tallow             Euphorbiaceae

  *Sesbania punicea*          rattlebox                  Fabaceae

  *Setaria viridis*           green foxtail              Poaceae

  *Sonchus asper*             spiny sowthistle           Asteraceae

  *Sonchus oleraceus*         common sowthistle          Asteraceae

  *Sporobolus indicus* var.   smutgrass                  Poaceae
  *indicus*                                              

  *Wisteria sinensis*         Chinese wisteria           Fabaceae

  *Xyris jupicai*             Richard\'s yellow-eyed     Xyridaceae
                              grass                      
  --------------------------- -------------------------- ------------------

**Vegetation Map**

The diversity of vegetation on St. Vincent NWR has been described in 21
cover classes that, for the most part, reflect the major vegetation
patterns of the refuge. The following describes the synonyms, extent,
topography, soils, appearance, ecology, and associated plant species for
each vegetation class. A cross reference of the vegetation classes
defined in this study compared to the natural plant community
descriptions for Florida (FNAI 1990) and previous studies are given in
Table 6.

**Table 6.** A cross comparison of vegetation classes and natural plant
communities as defined by the 1999 vegetation map of St. Vincent NWR,
FNAI (1998), and Thompson (1968).

+-----------------------+-------------------+--------------------------+
| 1999 Vegetation/Cover | FNAI (1998)       | Thompson (1968)          |
| Classes               |                   |                          |
+-----------------------+-------------------+--------------------------+
| Pine flatwoods        | Mesic flatwoods   | Slash pine-mixed         |
|                       |                   | understory               |
|                       |                   |                          |
|                       |                   | Slash pine-saw           |
|                       |                   | palmetto-*Ilex*          |
+-----------------------+-------------------+--------------------------+
| Pine-cabbage palm     | Wet flatwoods     | Slash pine-cabbage palm  |
| flatwoods             |                   | hammock                  |
+-----------------------+-------------------+--------------------------+
| Cabbage palm hammock  | Maritime hammock  | Cabbage palm             |
+-----------------------+-------------------+--------------------------+
| Scrub                 | Scrub             | Scrub oak dunes          |
+-----------------------+-------------------+--------------------------+
| Sand pine-scrub       | Scrub             | Sand pine-scrub oak      |
+-----------------------+-------------------+--------------------------+
| Live oak hammock      | Xeric hammock     | Mixed live oak-scrub oak |
|                       |                   |                          |
|                       |                   | Live oak dunes           |
|                       |                   |                          |
|                       |                   | Live oak-grass dune      |
+-----------------------+-------------------+--------------------------+
| Hardwood hammock      | Maritime hammock  | Hardwood hammock         |
+-----------------------+-------------------+--------------------------+
| Coastal grassland     | Coastal grassland | Slash pine-grass         |
+-----------------------+-------------------+--------------------------+
| Palustrine marsh      | Swale             | Sawgrass-emergent marsh  |
|                       |                   |                          |
|                       |                   | Cattail                  |
+-----------------------+-------------------+--------------------------+
| Palustrine shrub      | Baygall, swale    | Not identified           |
+-----------------------+-------------------+--------------------------+
| Palustrine open water | Coastal dune      | Freshwater pond          |
|                       | lakes             |                          |
+-----------------------+-------------------+--------------------------+
| Estuarine marsh       | Estuarine tidal   | Tidal marsh              |
|                       | marsh             |                          |
+-----------------------+-------------------+--------------------------+
| Estuarine shrub       | Estuarine tidal   | Not identified           |
|                       | marsh             |                          |
+-----------------------+-------------------+--------------------------+
| Estuarine open water  | Coastal dune      | Saltwater pond           |
|                       | lakes             |                          |
+-----------------------+-------------------+--------------------------+
| Beach dunes           | Beach dunes       | Beach                    |
+-----------------------+-------------------+--------------------------+
| Intertidal zone       | Uncolsolidated    | Beach                    |
|                       | substrate         |                          |
+-----------------------+-------------------+--------------------------+
| Oyster reefs          | Mollusk reefs     | Not identified           |
+-----------------------+-------------------+--------------------------+
| Intertidal flats      | Unconsolidated    | Not identified           |
|                       | substrate         |                          |
+-----------------------+-------------------+--------------------------+
| Developed             | Not identified    | Not identified           |
+-----------------------+-------------------+--------------------------+
| Managed marsh         | Not identified    | Not identified           |
+-----------------------+-------------------+--------------------------+
| Managed open water    | Not identified    | Not identified           |
+-----------------------+-------------------+--------------------------+

**Vegetation Class Descriptions**

***Pine Flatwoods***

**Synonyms:** Mesic slash pine flatwoods, mesic flatwoods, slash
pine-mixed understory, slash pine-saw palmetto-*Ilex*, *Pinus elliottii*
var. *elliottii / Ilex glabra* woodland, *Pinus elliottii* var.
*elliottii* / (*Sabal palmetto*) / *Serenoa repens-Ilex glabra*
woodland.

**Extent on Refuge:** Total acres = 4279.8 acres. Occurs on St. Vincent
Island, Mainland Unit and Pig Island. This vegetation type is the most
abundant vegetation type on the refuge. It makes up most of the forested
vegetation of St. Vincent Island where it occurs in low ridges between
sand dunes. On the mainland unit it makes up the majority of vegetation
on the northern portion of the unit. Pine flatwoods also make up the
interior forests of Pig Island.

**Topographic Position:** Low and nearly level terrain.

**Soils:** Mapped soil units associated with this vegetation type
include Duckston, Duckston-Rutledge-Corolla Complex, Leon Sand, and Lynn
Haven Sand. These soils are poorly drained soils on nearly level terrain
and are composed of fine sands to a depth of more that 80 inches. The
soils are of low fertility, low organic matter and moderate acidity.

**Hydrology:** Mesic sites that are seasonally flooded up to 6 months
per year. In dry periods the water table can fall below 24 inches from
the soil surface.

**Appearance:** In relatively natural conditions and under frequent fire
regimes (once every 3 to 5 years) this vegetation type is characterized
by an open to closed canopy of pine trees with little to no midstory, or
an understory of either continuous saw palmetto or a rich grass and herb
groundcover layer. In more fire suppressed sites, this vegetation type
will have a dense hardwood component, including significant height
growth of palmetto in the midstory and understory and a loss of native
herbs and grasses in the groundcover (Figure 1).

**Ecology:** Frequent, light intensity, surface fires are essential to
preserving and restoring this vegetation type. Frequent fire promotes
the dominance of native groundcover plants such as herbs and grasses and
decreases encroachment of woody vegetation into the midstory. In the
absence of fire, open pine flatwoods are quickly invaded by hardwoods
and shrubs that shade out and out compete native species in the
understory. Further, the increased presence of hardwoods and shrubs in
the midstory changes the behavior and intensity of fires as they burn
through the stand. Increased woody vegetation in the midstory results in
greater amounts of vertical fuels present and can lead to torching and
crowning up into the canopy, creating more intense fire behavior, less
ability for control and a higher potential for catastrophic fires.

There is little controversy that Florida is the thunderstorm capital of
the world and that frequent fires played a significant role in the
structure of plant communities on the landscape historically. Pine
flatwoods and other pine forests of North Florida are extremely
vulnerable to ignition during lightning activities and once ignited have
the potential to spread fire across the landscape due to the light fuels
present on the ground (i.e., pine needle litter, grassy understory,
etc). While there is little dispute that most lightning activities occur
during the summer months, there is still considerable debate about what
season to use prescribed fire in the management of these ecosystems.
This is a difficult issue since conditions during the summer or growing
season are drier and can lead to more intense fire behavior with
potential control problems than conditions during the dormant or winter
months. The most common practice used today in this vegetation type is
to introduce prescribed fire under cooler more controllable conditions
initially to reduce fuel hazards and then over time introduce growing
season burns for restoration. Growing season burns have several
beneficial effects in the flatwoods. First, growing season burns have a
greater impact on reducing woody vegetation than dormant season burns
(Robbins and Myers 1990). Second, many native grasses and herbs in the
understory flower and produce seeds (therefore increasing in numbers)
only following a growing season burn. This is especially important for
rare plants and plants of concern like wiregrass (*Aristida* spp.),
toothache grass (*Ctenium* spp.), pitcher plants (*Sarracenia* spp.) and
orchids (*Calapogon* spp., *Pogonia* spp.) for example.

**Vegetation:**

***Overstory:*** The overstory is made up of mostly slash pine (*Pinus
elliotii*) trees, but may include a few scattered trees of sweetgum
(*Liquidambar styraciflua*), cabbage palm (*Sabal palmetto*), Virginia
live oak (*Quercus virginiana*) and other oaks (*Quercus* spp.).

***Midstory:*** Frequently burned sites have very few species present;
however, less frequently burned sites may include regenerating overstory
species as well as red maple (*Acer rubrum*), common persimmon
(*Diospyros virginiana*), fetterbush (*Lyonia lucida*), sweetbay
(*Magnolia virginiana*), wax myrtle (*Myrica cerifera*), red bay
(*Persea borbonia* var. *borbonia*), dwarf live oak (*Quercus minima*),
myrtle oak (*Q. myrtifolia*), water oak (*Q. nigra*), and farkleberry
(*Vaccinium arboreum*).

***Understory:*** The understory includes regenerating overstory and
midstory species as well as huckleberrys (*Gaylussacia dumosa*, *G.
frondosa, G. mosieri*), St. John\'s-wort (*Hypericum* spp.), gallberry
(*Ilex glabra*) other hollies (*Ilex* spp.), winged sumac (*Rhus
copallinum*), dewberry species (*Rubus* spp.), greenbrier species
(*Smilax* spp.), eastern poison ivy (*Toxicodendron radicans*),
Darrow\'s blueberry (*Vaccinium darrowii*), and shiny blueberry (*V.
myrsinites*).

***Groundcover:*** The groundcover of this vegetation type is very
diverse and may include species of foxgloves (*Agalinis* spp.),
bluestems (*Andropogon* spp.), threeawns (*Aristida* spp.), asters
(*Aster* spp.), hairsedges (*Bulbostylis* spp.), vanillaleaf
(*Carphephorus* *odoratissimus*), spadeleaf (*Centella* *asiatica*),
spurred butterfly pea (*Centrosema* *virginianum*), thistles (*Cirsium*
spp.), pigeonwings (*Clitoria* spp.), tickseeds (*Coreopsis* spp.),
flatsedges (*Cyperus* spp.), witchgrasses (*Dichanthelium* spp.),
crabgrasses (*Digitaria* spp.), buttonweeds (*Diodia* spp.), sundews
(*Drosera* spp.), elephantsfoots (*Elephantopus* spp.), lovegrasses
(*Eragrostis* spp.), fleabanes (*Erigeron* spp.), pipeworts
(*Eriocaulon* spp.), eryngoes (*Eryngium* spp.), thoroughworts
(*Eupatorium* spp.), fingergrasses (*Eustachys* spp.), umbrellasedges
(*Fuirena* spp.), everlastings (*Gnaphalium* spp.), hedgehyssops
(*Gratiola* spp.), mille grains and bluets (*Hedyotis* spp.), frostweeds
(*Helianthemum* spp.), St John\'s-worts (*Hypericum* spp.), yellow
stargrasses (*Hypoxis* spp.), rushes (*Juncus* spp.), Carolina redroot
(*Lachnanthes* *caroliana*), pinweeds (*Lechea* spp.), lespedezas
(*Lespedeza* spp.), flaxes (*Linum* spp.), lobelias (*Lobelia* spp.),
goldencrest (*Lophiola* *aurea*), primrosewillows (*Ludwigia* spp.),
hornpods (*Mitreola* spp.), beebalms (*Monarda* spp.), muhlies
(*Muhlenbergia* spp.), gromwell (*Onosmodium* *virginianum*), devilwoods
(*Osmanthus* spp.), royal ferns (*Osmunda* spp.), panicgrasses
(*Panicum* spp.), nailworts (*Paronychia* spp.), crowngrasses
(*Paspalum* spp.), butterworts (*Pinguicula* spp.), camphorweeds
(*Pluchea* spp.), pogonias (*Pogonia* spp.), milkworts (*Polygala*
spp.), jointweeds (*Polygonella* spp.), mermaidweeds (*Proserpinaca*
spp.), bracken ferns (*Pteridium* spp.), bishopsweed (*Ptilimnium*
*capillaceum*), meadowbeauties (*Rhexia* spp.), snoutbeans (*Rhynchosia*
spp.), beaksedges (*Rhynchospora* spp.), rosegentians (*Sabatia* spp.),
plumegrasses (*Saccharum* spp.), bluestems (*Schizachyrium* spp.),
nutrushes (*Scleria* spp.), blueeyed grasses (*Sisyrinchium* spp.),
goldenrods (*Solidago* spp.), indiangrasses (*Sorghastrum* spp.),
ladiestresses (*Spiranthes* spp.), dropseeds (*Sporobolus* spp.), queens
delights (*Stillingia* spp.), bluecurls (*Trichostema* spp.),
bladderworts (*Utricularia* spp.), cowpeas (*Vigna* spp.), violets
(*Viola* spp.), chainferns (*Woodwardia* spp.), and yelloweyed grasses
(*Xyris* spp.).

![](media/image1.jpeg){width="6.010416666666667in"
height="8.399305555555555in"}Figure 1. Appearance of frequently burned
pine flatwoods vegetation class.

***Pine-Cabbage Palm Flatwoods***

**Synonyms:** Wet slash pine-cabbage palm flatwoods, low flatwoods,
pocosin, cabbage palm/pine savanna, hydric flatwoods, wet flatwoods,
slash pine-cabbage palm flatwoods, *Pinus elliottii* var. *elliottii* /
(*Sabal Palmetto*) / *Serenoa repens* - *Ilex glabra* woodland.

**Extent on Refuge:** Total acres = 426.2 acres. Occurs on St. Vincent
Island. On the island, it is found along pond margins of the
southeastern portion of the island and as small islands of woodlands
scattered in estuarine marshes of the northeastern portion of the
island.

**Topography:** Low flatlands, lower in slope than pine flatwoods.

**Soils:** Similar to pine flatwoods, Duckston,
Duckston-Rutledge-Corolla Complex, Duckston-Bohicket-Corolla Complex,
Leon Sand, and Lynn Haven soils. These soils are poorly drained soils on
nearly level terrain and composed of fine sands to a depth of more that
80 inches. The soils are of low fertility and low organic matter and are
slightly acidic.

**Hydrology:** Mesic to hydric sites that are seasonally flooded with
standing water for one or more months per year.

**Appearance:** This vegetation type is characterized by the relatively
open canopy of mixed pine and cabbage palm trees with either a dense
thicket of hardwood shrubs and small trees in the midstory and
understory with a sparse groundcover or a sparse midstory with a dense
groundcover of hydrophytic herbs and small shrubs (Figure 2).

**Ecology:** Pine-cabbage palm flatwoods occur in low lying areas that
can have standing water for at least one month per year. As a result,
hydrology is an important component of this vegetation type. Plant
species that occur in these flatwoods are wetland associated. They
either require or can live in saturated conditions for a part of the
life cycle. Alterations to the local hydrology can alter the composition
and structure of this vegetation type. In general more water allowed in
this vegetation type will promote the growth of deeper water species
such as cypress, sourgum, and bay. The removal of water from a site will
promote more upland species such as pines and oaks. Recovery from
hydrologic alterations in this vegetation type is slow and may lead to
the introduction of invasive species in more disturbed sites (FNAI
1990).

Although pine-cabbage palm flatwoods are found in wetland habitats,
periodic fires can burn across a site under drier conditions. Natural
fires are estimated to occur once every 3 to 10 years (FNAI 1990). Like
slash pine flatwoods, fires probably occurred in the summer during
active thunderstorm activity and when the water table fell below the
soil surface. Ignition probably occurs where more pine trees are found,
and fire spreads into areas of pine-cabbage palm mixed flatwoods,
although it is possible for ignition to actually occur in pine-cabbage
palm flatwoods. Depending on fuel conditions, catastrophic fires can
occur in this vegetation type. Areas with a long absence of fire (i.e.,
more than 25 years) and a thick midstory of shrubs, vines, and small
hardwood trees can develop to create a vertical wall of fuel that when
covered with dead pine needles and cabbage palm fronds from the canopy
will ignite and cause extreme fire behavior (e.g., torching and
crowning). More frequently burned areas will have a reduced midstory of
shrubs and woody growth, producing a low creeping surface fire.
Management of this vegetation type with fire is similar to pine
flatwoods. Fuel reduction burns occur in the winter or dormant season,
but over time, growing season burns may be introduced at a site as well.

**Vegetation:**

***Overstory:*** The overstory is dominated by slash pine (*Pinus*
*elliottii*) and cabbage palm (*Sabal* *palmetto*) trees. Other trees in
the canopy may include red cedars (*Juniperus* *virginiana*) and live
oaks (*Quercus* *virginiana*) .

***Midstory:*** The midstory is made up of regenerating overstory
species as well as seacoast marshelder (*Iva* *imbricata*), wax myrtle
(*Myrica* *cerifera*), and oak species (*Quercus* spp.).

***Understory:*** The understory includes regenerating midstory and
overstory species as well as St. John\'s-worts (*Hypericum* spp.),
hollies (*Ilex* spp.), winged sumac (*Rhus* *copallinum*), dewberries
(*Rubus* spp.), greenbriers (*Smilax* spp.), eastern poison ivy
(*Toxicodendron* *radicans*), blueberries (*Vaccinium* spp.), and grapes
and muscadines (*Vitis* spp.).

***Groundcover:*** The groundcover is sparse but may include scattered
stems of sedges (*Carex* spp.), ticktrefoils (*Desmodium* spp.),
witchgrasses (*Dichanthelium* spp.), thoroughworts (*Eupatorium* spp.),
morningglories (*Ipomoea* spp.), rushes (*Juncus* spp.), primrosewillows
(*Ludwigia* spp.), panicgrasses (*Panicum* spp.), golden polypody
(*Phlebodium* *aureum*), camphorweeds (*Pluchea* spp.), and chickweeds
(*Stellaria* spp.).

![](media/image2.jpeg){width="6.0in" height="3.9229166666666666in"}

Figure 2. Appearance of pine-cabbage palm flatwoods vegetation class.

***Cabbage Palm Hammock***

**Synonyms:** Maritime hammock, coastal hammock, maritime forest,
tropical hammock, *Sabal palmetto* seasonally flooded woodland, *Sabal
Palmetto* woodland, *Quercus virginiana* - *Sabal palmetto*- *Persea
borbonia* / *Serenoa repens* - *Ilex vomitoria*.

**Extent on Refuge:** Total acres = 106.5 acres. Occurs on St. Vincent
Island. On the island, it is found in two locations. It occurs adjacent
to managed marshes and ponds of the southeastern portion of the island
as well as a small line of cabbage palm hammock along the eastern shore.

**Topography:** Low areas of shorelines, lakes, and pond margins.

**Soils:** This vegetation type occurs in association with Corolla sands
and the Duckston-Bohicket-Corolla soil complex. These soils are very
poorly drained soils of flat terrain. The soils are made up of sand to a
depth of over 80 inches with little organic content, low fertility and
moderate acidity. These soils may be tidally influenced.

**Hydrology:** Mesic to hydric sites with seasonally high water table
present within 12 to 36 inches of soil surface 3 to 6 months per year.

**Appearance:** Cabbage palm hammocks are characterized as narrow bands
of hardwood forests along shorelines and edges of lakes and ponds. On
the refuge, this vegetation type is characterized as canopy of palm
trees, with a few scattered live oak trees. There is little to no
midstory or understory and a sparse groundcover (Figure 3).

**Ecology:** Cabbage palm hammocks occur along coastlines and marsh
edges where saltwater flooding, salt spray, and strong winds affect the
vegetation. As a result the plant species that occur in this vegetation
are adapted to these harsh conditions. In general, this vegetation type
is fairly resistant to fire. There is little to no midstory or
understory and little groundcover. Fuels in this vegetation type are
poor for spreading a fire and include dead palm fronds that hang from
the canopy, dried up sea wrack, and overwash debris materials such as
driftwood. Natural fires probably occurred once every 26 to 100 years
(FNAI 1990). Fires that do burn across this vegetation type probably
ignite in adjacent pine stands and under extreme drought conditions can
be catastrophic (i.e., all vegetation consumed).

**Vegetation:**

***Overstory:*** The overstory is dominated by cabbage palm (*Sabal*
*palmetto*) trees.

***Midstory:*** The midstory is composed of juvenile overstory species
and scattered red cedars (*Juniperus* *virginiana*), hollies (*Ilex*
spp.), and hackberry (*Celtis* *laevigata*) trees.

***Understory:*** The understory is fairly sparse, but scattered
regenerating overstory and midstory species may be present as well as
coralbean (*Erythrina* *herbacea*), Virginia creeper (*Parthenocissus*
*quinquefolia*), and yuccas (*Yucca* spp.).

***Groundcover:*** The groundcover is very sparse and may include
woodoats (*Chasmanthium* spp.), bedstraws (*Galium* spp.), basketgrasses
(*Oplismenus* spp.), and blacksnakeroots (*Sanicula* spp.).

![](media/image3.jpeg){width="6.49375in"
height="4.382638888888889in"}Figure 3. Appearance of cabbage palm
hammock vegetation class.

***Scrub***

**Synonyms:** Sand pine scrub, Florida scrub, sand scrub, rosemary
scrub, oak scrub, scrub oak, *Pinus clausa / Quercus myrtifolia -
Quercus geminata - Quercus chapmanii* woodland, *Ceratiola ericoides*
shrubland, and *Ceratiola ericoides - Quercus geminata - Serenoa repens/
Cladonia* spp. - *Cladina* spp. shrubland.

**Extent on Refuge:** Total acres = 1557.9 acres. Occurs on St. Vincent
Island and Pig Island. This vegetation type is common on St. Vincent
Island. Here, it occurs associated with sand dunes that run
northwest-southeast along the interior of the island. On Pig Island, a
mixture of scrub and sand pine-scrub can be found along the northern
portion of the island. This mixed vegetation type occurs on high sand
dunes that run northwest-southeast on Pig Island.

**Topography:** Older sand dunes and along slopes of high sand ridges.
Strongly sloping to nearly level terrain.

**Soils:** This vegetation type is associated with Mandarin-Resota*,*
Corolla-Duckston, and Kershaw-Ortega fine sands. These soils are
excessively drained to moderately drained soils. They are made up of
fine gray to white sands. These soils have low fertility and low organic
matter content.

**Hydrology:** Xeric conditions, there is no water table within 80
inches of the soil surface.

**Appearance:** This vegetation type is considered both a woodland and a
shrubland, depending on the fire history of the site. In a more mature
stand that has had no recent fire in the past 25 or more years, this
vegetation type takes on more of a woodland aspect as the scrub oaks and
sand pine enter into the canopy. At this stage of succession a scrub
community will have a closed to open canopy of sand pine and sand live
oak trees, with dense clumps or thickets of scrub oaks and other
hardwood shrubs in the midstory and understory. The groundcover is
generally sparse and dominated by lichens and few herbs. With more
frequent fire, this vegetation type is considered more of a shrubland.
Florida rosemary (*Ceratiola ericoides*) and false rosemary (*Conradina
canescens*) will dominate the canopy which may only be several feet
high. The groundcover remains sparse in frequently burned sites (Figure
4).

**Ecology:** Scrub is associated with very dry, xeric conditions. As
such, the plant species that occur on this vegetation type are adapted
to living with little water availability. To live in this environment,
plants have evolved adaptations to conserve water similar to plants of
the desert.

Fire is an important ecological process for scrub vegetation. Frequent
surface fires are not prevalent in this system, so fires are
catastrophic (i.e., consuming and killing most vegetation). Natural fire
frequencies for this vegetation type are estimated to be once every 20
to 80 years or more. Plant species growing in scrub exhibit adaptations
to catastrophic fires. Serotinous species such as sand pine, for
example, will open their cones and release seeds only under high heat
conditions. Other plants have underground root systems that allow the
plant to resprout immediately following fire. Fire begins a regeneration
process in this vegetation type, similar to western forest ecosystems.

**Vegetation:**

***Overstory:*** There is no overstory species in this vegetation type,
though an occasional slash pine (*Pinus elliottii*) tree may be present

***Midstory:*** Depending on fire history, the midstory may be a well
developed tall shrubland in less frequently burned sites and may include
Florida rosemary (*Ceratiola ericoides*), rusty staggerbush (*Lyonia
ferruginea*), scrub oak species (*Quercus myrtifolia, Q. geminata, Q.
Chapmanii*), and saw palmetto (*Serenoa repens*). More frequently burned
sites will not have a well developed shrub layer.

***Understory:*** The understory will include regenerating midstory
species and may also include false rosemary (*Conradina canescens*),
earleaf greenbrier (*Smilax auriculata*), Darrow\'s blueberry
(*Vaccinium darrowii*), Shiny blueberry (*V. myrsinites*) and yuccas
(*Yucca* spp.)

***Groundcover:*** The groundcover is mostly open sands and lichens
(*Cladonia* spp.), but may also include scattered stems of threeawns
(*Aristida* spp.), hairsedges (*Bulbostylis* spp.), tread-softly
(*Cnidoscolus* *stimulosus*), milkpeas (*Galactia* spp.), gayfeathers
(*Liatris* spp.), toadflaxes (*Linaria* spp.), lupines (*Lupinus* spp.),
Florida beargrass (*Nolina atopocarpa*), pricklypear cacti (*Opuntia*
spp.), jointweeds (*Polygonella* spp.), snoutbeans (*Rhynchosia* spp.),
beaksedges (*Rhynchospora* spp.), nutrushes (*Scleria* spp.), gum bully
(*Sideroxylon lanuginosum*), sandgrasses (*Triplasis* spp.), and
Carolina yelloweyed grass (*Xyris caroliniana*).

![](media/image4.jpeg){width="6.49375in"
height="4.402083333333334in"}Figure 4. Appearance of scrub vegetation
class.

***Sand Pine-Scrub***

**Synonyms:** Scrub, Florida scrub, sand scrub, rosemary scrub, oak
scrub, scrub oak, *Pinus clausa / Quercus myrtifolia - Quercus
geminata - Quercus chapmanii* woodland, *Ceratiola ericoides* shrubland,
*Ceratiola ericoides - Quercus geminata - Serenoa repens/ Cladonia*
spp. - *Cladina* spp. shrubland.

**Extent on Refuge:** Total acres = 13.5 acres. Occurs on St. Vincent
Island and Pig Island. This vegetation type is fairly limited on St.
Vincent Island and currently occurs in one small area in the
northwestern portion of the island along Road D between Road 2 and Road
3. On Pig Island, this vegetation type occurs in a dense stand on the
northern tip of the island and extends along both the eastern and
western sides of the island. Sand pine-scrub is a mixed vegetation type
of Pig Island. The acreage estimated includes only pure sand pine
dominated portions of the islands.

**Topography:** Older sand dunes and along slopes of high sand ridges.
Strongly sloping to nearly level terrain.

**Soils:** This vegetation type is associated with Mandarin-Resota*,*
Corolla-Duckston, and Kershaw-Ortega fine sands. These soils are
excessively drained to moderately drained soils. They are made up of
fine gray to white sands. These soils have low fertility and low organic
matter content.

**Hydrology:** Xeric conditions, there is no water table within 80
inches of the soil surface.

**Appearance:** This vegetation type is considered both a woodland and a
shrubland, depending on the fire history of the site. In a more mature
stand that has had no recent fire in the past 30 or more years, this
vegetation type takes on more of a woodland aspect as the scrub oaks and
sand pine enter into the canopy. At this stage of succession a scrub
community will have a closed to open canopy of sand live oak trees, with
dense clumps or thickets of scrub oaks and other hardwood shrubs in the
midstory and understory. The groundcover is generally sparse and
dominated by lichens and few herbs. In more recently burned sites where
there is no canopy layer of scrub oak trees, this vegetation type
appears as a shrubland. At this stage, dense thickets of younger scrub
oaks and scrub shrubs dominate the midstory and understory layers with
little groundcover except lichens and a few scattered herbs (Figure 5).

**Ecology:** The ecology of sand pine-scrub is similar to scrub
vegetation, the difference from scrub is the dominance of sand pine in
this vegetation type. Sand pine-scrub is associated with very dry, xeric
conditions. As such, the plant species that occur on this vegetation
type are adapted to living with little water availability. To live in
this environment, plants have evolved adaptations to conserve water
similar to plants of the desert.

Fire is an important ecological process of sand pine-scrub vegetation.
Because frequent surface fires are not prevalent in this system, fires
are catastrophic (i.e., consuming and killing most vegetation). Natural
fire frequencies for this vegetation type are estimated to be once every
20 to 80 years or more. Plant species growing in scrub exhibit
adaptations to catastrophic fires. Serotinous species such as sand pine,
for example, will open their cones and release seeds only under high
heat conditions. Other plants have underground root systems that allow
the plant to resprout immediately following fire. Fire begins a
regeneration process in this vegetation type, similar to western forest
ecosystems.

**Vegetation:**

***Overstory:*** The overstory in this vegetation type is dominated by
sand pine (*Pinus* *clausa*); however, an occasional slash pine (*Pinus*
*elliottii*) may also occur in the overstory.

***Midstory:*** The midstory is similar to scrub vegetation and varies
with fire history. Less frequently burned sites may include Florida
rosemary (*Ceratiola* *ericoides*), rusty staggerbush (*Lyonia*
*ferruginea*), scrub oak species (*Quercus* *myrtifolia*, *Q. geminata,
Q. Chapmanii*), and saw palmetto (*Serenoa repens*). More frequently
burned sites will not have a well developed shrub layer.

***Understory:*** The understory is also similar to scrub vegetation and
will include regenerating midstory species and may also include false
rosemary (*Conradina canescens*), saw greenbrier (*Smilax auriculata*),
Darrow\'s blueberry (*Vaccinium darrowii*), Shiny blueberry (*V.
myrsinites*), and yuccas (*Yucca* spp.)

***Groundcover:*** The groundcover is also similar to scrub vegetation
and is made up of mostly open sands and lichens (*Cladonia* spp.), but
it may also include scattered stems of threeawns (*Aristida* spp.),
hairsedges (*Bulbostylis* spp.), tread-softly (*Cnidoscolus*
*stimulosus*), milkpeas (*Galactia* spp.), gayfeathers (*Liatris* spp.),
toadflaxes (*Linaria* spp.), lupines (*Lupinus* spp.), Florida beargrass
(*Nolina atopocarpa*), pricklypear cacti (*Opuntia* spp.), jointweeds
(*Polygonella* spp.), snoutbeans (*Rhynchosia* spp.), beaksedges
(*Rhynchospora* spp.), nutrushes (*Scleria* spp.), gum bully
(*Sideroxylon lanuginosum*), sandgrass (*Triplasis* spp.), and Carolina
yelloweyed grass (*Xyris caroliniana*).

![](media/image5.jpeg){width="6.3in" height="4.061805555555556in"}Figure
5. Appearance of sand pine- scrub vegetation class.

***Live Oak Hammock***

**Synonyms:** Xeric hammock, xeric forest, sand hammock, live oak
forest, oak woodland, oak hammock, live oak, mixed live oak-scrub oak,
live oak dunes, live oak-grass dunes, *Quercus geminata - (Quercus
virginiana) / Serenoa repens - Lyonia fruticosa* forest, *Quercus
virginiana / Ilex vomitoria / Oplismenus setarius* forest, *Quercus
virginiana / Serenoa repens* forest, *Quercus virginiana / vaccinium
arboreum - Ilex vomitoria* forest.

**Extent on Refuge:** Total acres = 420.9 acres. Occurs on St. Vincent
Island and the Mainland unit. On St. Vincent Island, this vegetation
type is found along the sand ridges of the southeastern portion of the
island. There are small patches of live oak hammocks along the
northeastern portion of the island as well. On the mainland unit, there
is a small live oak hammock on the northern portion of the unit.

**Topography:** Older sand dunes and along slopes of high sand ridges.
Strongly sloping to nearly level terrain.

**Soils:** This vegetation type is most strongly associated with
Kershaw-Ortega sands, but it can occur where other excessively drained
soils such as Mandarin-Resota*,* Corolla-Duckston are found on the
refuge. These soils are made up of fine sands to a depth of over 80
inches below the soil surface. They make up the older sand dunes and
higher sand ridges that occur on the refuge. These soils are of low
fertility and low organic content.

**Hydrology:** Xeric conditions, no water table present within 80 inches
of the soil surface.

**Appearance:** In more mature forests, this vegetation type appears as
an open or closed canopy forest with tall live oak trees. At this stage
of succession, there is little to no midstory and an understory of
palmettos below with a sparse groundcover of herbs or grasses. This
vegetation type, as it succeeds from a scrub oak shrubland to a live oak
forest (see ecology section below) may appear as a scrubby dense low
canopy forest of scrub oaks and live oak trees with a dense shrubby
midstory and understory of hardwoods with little to no groundcover
present (Figure 6).

**Ecology:** Live oak hammocks are associated with dry, xeric
conditions. This vegetation type has been considered to be a late
successional stage of scrub vegetation and develops in the absence of
fire for more than 30 years (FNAI 1990). In general, this vegetation
type is resistant to fire. The natural fire frequency of this vegetation
type is estimated to be once every 30 or more years. The dominance of
live oak trees and other hardwoods in the canopy and midstory of the
hammock produce poor fuel conditions due to the incombustible oak leaf
litter. However, under drought conditions, the palmetto understory may
promote the spread of fire throughout a site. In general, fires that do
burn across this vegetation type will be catastrophic, consuming and
killing most vegetation within the hammock.

**Vegetation:**

***Overstory:*** The dominant overstory species is live oak (*Quercus
virginiana*)

***Midstory:*** The midstory is sparse and includes regenerating live
oaks as well as American beautyberry (*Callicarpa americana*), common
persimmon (*Diospyros virginiana*), hollies (*Ilex* spp.), southern
magnolia (*Magnolia grandiflora*), and other oaks (*Quercus* spp.).

***Understory:*** The understory may include regenerating midstory
species and false rosemary (*Conradina canescens*), saw palmetto
(*Serenoa repens*), and blueberries (*Vaccinium* spp.).

***Groundcover:*** There is a sparse groundcover that may include
species of bluestems (*Andropogon* spp.), threeawns (*Aristida* spp.),
hairsedges (*Bulbostylis* spp.), butterfly peas (*Centrosema* spp.),
partridgepeas (*Chamaecrista* spp.), bush goldenrod (*Chrysoma*
*pauciflosculosa*), goldenasters (*Chrysopsis* spp.), pigeonwings
(*Clitoria* spp.), tread-softly (*Cnidosculus* *stimulosus*), dayflowers
(*Commelina* spp.), flatsedges (*Cyperus* spp.), ticktrefoil
(*Desmodium* spp.), witchgrasses (*Dichanthelium* spp.), crabgrasses
(*Digitaria* spp.), Elephantsfoots (*Elephantopus* spp.), lovegrasses
(*Eragrostis* spp.), thoroughworts (*Eupatorium* spp.), flattop
goldenrod (*Euthamia* *graminifolia*), cottonweed (*Froelichia*
*floridana*), milkpeas (*Galactia* spp.), bedstraws (*Galium* spp.),
beeblossoms (*Gaura* spp.), everlastings (*Gnaphalium* spp.), frostweeds
(*Helianthemum* spp.), St John\'s-worts (*Hypericum* spp.), pinweeds
(*Lechea* spp.), lespedezas (*Lespedeza* spp.), toadflaxes (*Linaria*
spp.), lupines (*Lupinus* spp.), prickly pear cacti (*Opuntia* spp.),
nailworts (*Paronychia* spp.), crowngrasses (*Paspalum* spp.),
groundcherries (*Physalis* spp.), resurrection fern (*Pleopeltis
polypodioides*), jointweeds (*Polygonella* spp.), beaksedges
(*Rhynchospora* spp.), bluestems (*Schizachyrium* spp.), nutrushes
(*Scleria* spp.), gum bully (*Sideroxylon* *lanuginosum*), goldenrods
(*Solidago* spp.), indiangrasses (*Sorghastrum* spp.), bluecurls
(*Trichostema* spp.), sandgrasses (*Triplasis* spp.), and Carolina
yelloweyed grass (*Xyris caroliniana*).

![](media/image6.jpeg){width="6.3in" height="4.104166666666667in"}Figure
6. Appearance of live oak hammock vegetation class.

***Hardwood Hammock***

**Synonyms:** Maritime hammock, coastal hammock, maritime forest,
tropical hammock, *Quercus virginiana-Sabal palmetto - Juniperus
virginiana* var. *silicicola* / *Persea borbonia, Quercus virginiana -
Sabal palmetto - Persea borbonia / Serenoa repens - Ilex vomitoria*.

**Extent on Refuge:** Total acres = 166.9 acres. Occurs on St. Vincent
Island. This vegetation type is found along the northern portion of the
island and along the eastern edge of the island. It forms forests
adjacent to the shoreline.

**Topography:** Lower slopes, nearly level terrain.

**Soils:** This vegetation type is associated with the
Duckston-Bohicket-Corolla soil complex. These soils are very poorly
drained soils that occur on low ridges, flats and in narrow strips along
coastlines. Other soils of the flatwoods such as the Leon and Lynn Haven
sands may also support hardwood hammocks.

**Hydrology:** Mesic sites that are seasonally flooded up to 6 months
per year. In dry periods the water table can fall below 24 inches from
the soil surface.

**Appearance:** This vegetation type is characterized as a closed canopy
forest of mixed hardwood tree species, a well developed midstory and
understory of mixed hardwoods, some palmetto and a sparse groundcover of
herbs and grasses (Figure 7).

**Ecology:** Hardwood hammocks are restricted to narrow bands along
shorelines. As a result, the plants of this vegetation type are exposed
to episodic saltwater flooding, and strong winds during storm events. In
addition, this vegetation type occurs in low lying areas where standing
water can occur for long periods of time throughout the year.
Alterations to local hydrology could significantly affect the
composition and structure of this vegetation type. Allowing more water
to this site may promote deeper water species such as red bay and
sourgum. Restricting water from this site may promote more oaks and
other hardwoods to replace the cabbage palm and pines over time.

Hardwood hammocks are fairly resistant to fire. The fuels are poor
because of the incombustible nature of the oak and hardwood litter that
can not carry a fire well. Natural fire frequencies for this vegetation
type are estimated to be once every 26 to 100 years (FNAI 1990).
Ignition probably occurs in adjacent pine flatwoods and burns up to the
boundary of this vegetation type. Under extreme drought conditions fires
that burn through hardwood hammocks are catastrophic, consuming and
killing most vegetation.

**Vegetation:**

***Overstory:*** The overstory is composed of a mixture of slash pine
(*Pinus elliottii*), live oak (*Quercus virginiana*), and cabbage palm
(*Sabal palmetto*) trees in equal occurrence. Other species that may be
present in the canopy can include red cedar (*Juniperus virginiana*) and
southern magnolia (*Magnolia grandiflora*).

***Midstory:*** Depending on the maturity of the stand the midstory can
include species of the canopy as well as American beautyberry
(*Callicarpa americana*), hackberry (*Celtis laevigata*), hollies
(*Ilex* spp.), wax myrtle (*Myrica cerifera*), and Hercule\'s-club
(*Zanthoxylum clava-herculis*).

***Understory:*** The understory can include regenerating midstory
species as well as Virginia creeper (*Parthenocissus quinquefolia*), saw
palmetto (*Serenoa repens*), greenbriers (*Smilax* spp.), and yuccas
(*Yucca* spp.).

***Groundcover:*** The groundcover is very sparse in this vegetation
type and may include woodoats (*Chasmanthium* spp.), coralbeans
(*Erythrina herbacea*), bedstraws (*Galium* spp.), basketgrasses
(*Oplismenus* spp.), woodsorrels (*Oxalis* spp.), golden polypody
(*Phlebodium* *aureum*), resurrection fern (*Pleopeltis polypodioides*),
and blacksnakeroots (*Sanicula* spp.).

![](media/image7.jpeg){width="6.5in" height="4.395833333333333in"}Figure
7. Appearance of hardwood hammock vegetation class.

***Coastal Grassland***

**Synonyms:** Coastal savanna, salt flat, overwash plain, slash
pine-grass, *Uniola paniculata - Schizachyricum maritimum - Hydrocotyle
bonariensis* herbaceous vegetation.

**Extent on Refuge:** Total acres = 43.9 acres. Occurs on St. Vincent
Island. This vegetation type is found along the southeastern tip of the
island. It makes up a narrow strip of grasslands adjacent to the beach
dune vegetation along the shoreline.

**Topography:** On nearly level terrain associated with inland side of
fore dunes and high sand ridges along coastline.

**Soils:** This vegetation type is associated with excessively to
somewhat poorly drained soils of the sand dunes adjacent to the
coastline such as the Newhan-Corolla complex, and Kureb-Corolla complex.
These are sandy soils to a depth of more than 80 inches.

**Hydrology:** Mesic to hydric conditions, this vegetation type may be
exposed to extreme, high-water salt pulses during storm events along the
coast and may exhibit flooding from 1 to 6 months per year.

**Appearance:** This vegetation type is characterized as a treeless open
flat land with a sparse to dense groundcover of grasses, prostrate
vines, and herbaceous species that are exposed to beach and coastline
conditions. On more established sites, a small cluster of pine trees or
shrubs may occur (Figure 8).

**Ecology:** Coastal grasslands are found in low, flat areas behind the
foredunes along the coast. This vegetation type occurs in an area
subject to episodic saltwater flooding, strong winds, and overwash
deposition during storm events. As a result most of the plant species
found in this vegetation type are adapted to high salinity pulses and
windy conditions. Most of the plant species that occur in this
vegetation type are also species of the beach vegetation. Frequent fires
may play an important role in this vegetation type by reducing the woody
growth and maintaining a grass-dominated groundcover. While fires
probably ignite in adjacent pine flatwoods the fine fuels of this
vegetation type promote the spread of fire. Natural fires probably
occurred in this vegetation type once every 3 to 5 years.

**Vegetation:**

***Overstory:*** This vegetation type is considered a grassland. There
are no dominant overstory species, though an occasional slash pine
(*Pinus elliottii*) may occur.

***Midstory:*** As a grassland, there are no dominant midstory species.
Scattered shrubs such as saltwater falsewillow (*Baccharis*
*angustifolia*), marshelder (*Iva* spp.), red cedar (*Juniperus*
*virginiana*) and wax myrtle (*Myrica cerifera*), may occur.

***Understory:*** There are no dominant understory species in this
grassland vegetation type; however, scattered juveniles of midstory
shrubs may be present.

***Groundcover:*** The groundcover in this vegetation type is made up of
salt tolerant and maritime species and may include asters (*Aster*
spp.), bushy seaside oxeye (*Borrichia* *frutescens*), sandburs
(*Cenchrus* spp.), crotons (*Croton* spp.), buttonweeds (*Diodia* spp.),
lovegrasses (*Eragrostis* spp.), sunflowers (*Helianthus* spp.),
marshpennyworts (*Hydrocotyle* spp.), morningglories (*Ipomoea* spp.),
muhlies (*Muhlenbergia* spp.), eveningprimroses (*Oenothera* spp.),
prickly pear cacti (*Opuntia* spp.), panicgrasses (*Panicum* spp.),
crowngrasses (*Paspalum* spp.), fogfruits (*Phyla* spp.), groundcherries
(*Physalis* spp.), saltworts (*Salsola* spp.), bluestems
(*Schizachyrium* spp.), goldenrods (*Solidago* spp.), cordgrasses
(*Spartina* spp.), and seaoats (*Uniola* spp.), cowpeas (*Vigna* spp.).

![](media/image8.jpeg){width="6.489583333333333in"
height="4.38125in"}Figure 8. Appearance of coastal grassland vegetation
class.

***Palustrine Marsh***

**Synonyms:** Swale, sawgrass-emergent marsh, cattail, freshwater marsh,
slough, *Cladium mariscoides* Herbaceous Vegetation, *Cladium
mariscoides - Eleocharis equisetoides* Herbaceous Vegetation.

**Extent on Refuge:** Total acres = 668.4 acres. Occurs on St. Vincent
Island. This vegetation type occurs mostly in narrow strips in the
swales between dunes and pine flatwoods of the interior of the island.
This vegetation type makes up the headwaters of the ponds and lakes of
the island.

**Topography:** Low nearly level terrain.

**Soils:** The soils associated with this vegetation type include
Maurepas muck, and Rutledge loamy fine sand. These soils are poorly
drained soils of brackish marshes and swamps. There is generally a mucky
or loamy sand within the top 8 inches of the soil surface and sands
below to a depth of 80 inches or more. These soils are fertile and
contain a large amount of organic matter.

**Hydrology:** Mesic to hydric conditions, a high water table can be at
or above the soil surface for 3 to 6 months per year.

**Appearance:** This vegetation type is characterized as an open,
treeless grassland that has standing water in it a good portion of the
year of following precipitation events. The vegetation is composed
mainly of herbaceous species of emergent wetland species that form a
continuous groundcover. Where vegetation includes woody shrubs and small
trees the vegetation type is considered a palustrine shrub class (Figure
9).

**Ecology:** Palustrine marsh is a hydrologically driven ecosystem. The
water table of this vegetation type is above the soil surface for most
of the year. At times of the year in drier periods when the water levels
are not maintained by ground water tables, levels are maintained by
surface water run-off during precipitation events. As a result of the
continued presence of water at or above the soil surface, the plant
species associated with this vegetation type are obligate wetland
species requiring flooded conditions throughout most or all of its life
cycle. Alterations to the local hydrology would significantly impact the
species composition and structure of this vegetation type. Increased
water levels may promote more deeper-water-tolerant species such as
cattails, cypress, red maple, bays, sourgum and others. Decreased water
levels may promote a transition to palustrine shrub vegetation of dense
shrubs, increased hardwoods and willow trees. In addition, alterations
to local hydrology may allow invasive species to colonize an area, under
conditions of either increased or decreased water to a site. Chinese
tallow, cogongrass, and cattails for example, can be extremely
aggressive in response to changes in hydrology.

Fire may play an important ecological role in palustrine marshes.
Periodic surface and ground fires are common in this vegetation type.
Natural fire frequencies for this vegetation type are estimated to be
once every 1 to 3 years (FNAI 1990). Frequent fires in this ecosystem
reduce the invasion of shrubs and woody growth into a site and promote
the presence of a grass dominated ecosystem. In frequently burned sites
where soils are saturated, surface fires will ignite and the fine fuels
of grass and dead grass litter will promote fire spread. Under drier
conditions when soils are not saturated, a ground fire can occur where
the organic peat layer ignites and can continue to burn underground for
long periods of time. The results of peat fires in marshes can reduce
several in of organic peat accumulations.

**Vegetation:**

***Overstory:*** Few overstory species are present in this vegetation
type but may include red maple (*Acer rubrum*), Carolina willow (*Salix
caroliniana*), or baldcypress (*Taxodium distichum*).

***Midstory:*** There are few midstory species present in this
vegetation type but may include regenerating overstory species as well
as common buttonbush (*Cephalanthus occidentalis*), corkwood (*Leitneria
floridana*), sweetbay (*Magnolia virginiana*), wax myrtle (*Myrica
cerifera*), swamp bay (*Persea palustris*), Carolina willow (*Salix
caroliniana*), and sourgum (*Nyssa* spp.).

***Understory:*** The understory can include midstory species as well as
amaranths (*Amaranthus* spp.), rosemallows (*Hibiscus* spp.), dewberries
(*Rubus* spp.), elderberries (*Sambucus* spp.), and greenbriers
(*Smilax* spp.).

***Groundcover:*** The groundcover is dominated by Jamaica swamp
sawgrass (*Cladium jamaicense*), other species may include foxgloves
(*Agalinis* spp.), redstems (*Ammannia* spp.), milkweeds (*Asclepias*
spp.), asters (*Aster* spp.), waterhyssop (*Bacopa* spp.), screwstems
(*Bartonia* spp.), false nettles (*Boehmeria* spp.), waterstarworts
(*Callitriche* spp.), grasspinks (*Calopogon* spp.),
Bandana-of-the-Everglades (*Canna flaccida*), sedges (*Carex* spp.),
dodders (*Cuscuta* spp.), flatsedges (*Cyperus* spp.), witchgrasses
(*Dichanthelium* spp.), buttonweeds (*Diodia* spp.), barnyardgrasses
(*Echinochloa* spp.), spickerushes (*Eleocharis* spp.), thoroughworts
(*Eupatorium* spp.), flattop goldenrod (*Euthamia* *graminifolia*),
bedstraws (*Galium* spp.), umbrellasedges (*Fuirena* spp.), mille grains
and bluets (*Hedyotis* spp.), mudplantains (*Heteranthera* spp.),
marshpennyworts (*Hydrocotyle* spp.), bushmints (*Hyptis* spp.),
jewelweeds (*Impatiens* spp.), irises (*Iris* spp.), rushes (*Juncus*
spp.), Carolina redroot (*Lachnanthes* *caroliana*), sprangletops
(*Leptochloa* spp.), primrosewillows (*Ludwigia* spp.), watergrasses
(*Luziola* spp.), hempvines (*Mikania* spp.), muhlies (*Muhlenbergia*
spp.), goldenclub (*Orontium* *aquaticum*), devilwoods (*Osmanthus*
spp.), cinammon fern (*Osmunda cinnamomea*), panicgrasses (*Panicum*
spp.), crowngrasses (*Paspalum* spp.), arrow arums (*Peltandra* spp.),
common reeds (*Phragmites* spp.), camphorweeds (*Pluchea* spp.),
knotweeds (*Polygonum* spp.), rustweed (*Polypremum* *procumbens*),
pickerelweeds (*Pontederia* spp.), mermaidweeds (*Proserpinaca* spp.),
mock bishopsweed (*Ptilimnium capillaceum*), meadowbeauties (*Rhexia*
spp.), docks (*Rumex* spp.), rosegentians (*Sabatia* spp.), plumegrasses
(*Saccharum* spp.), arrowhead (*Sagittaria* spp.), lizard\'s tail
(*Saururus cernuus*), bulrushes (*Scirpus* spp.), foxtails (*Setaria*
spp.), cordgrass (*Spartina* spp.), wood sages (*Teucrium* spp.),
fireflag (*Thalia* *geniculata*), cattails (*Typha* spp.), bladderworts
(*Utricularia* spp.), vervains (*Verbena* spp.), vetches (*Vicia* spp.),
chainferns (*Woodwardia* spp.), yelloweyed grasses (*Xyris* spp.), and
wild rice (*Zizania* *aquatica*).

![](media/image9.jpeg){width="6.4in" height="4.307638888888889in"}Figure
9. Appearance of palustrine marsh vegetation class.

***Palustrine Shrub***

**Synonyms:** Baygall, swales, *Salix caroliniana* shrubland, *Salix
caroliniana* woodland, *Cyrilla racemiflora-Persea palustris-Magnolia
virginiana* shrubland.

**Extent on Refuge:** Total acres = 106.5 acres. Occurs on St. Vincent
Island. This vegetation type is found along the margins of freshwater
and managed open water areas of the interior and southern portions of
the island.

**Topography:** Low, nearly level terrain.

**Soils:** The soils associated with this vegetation type are similar to
the soils of palustrine marshes and include Maurepas muck, and Rutledge
loamy fine sand. These soils are poorly drained soils of brackish
marshes and swamps. There is generally a mucky or loamy sand within the
top 8 inches of the soil surface and sands below to a depth of 80 inches
or more. These soils are fertile and contain a large amount of organic
matter.

**Hydrology:** Mesic to hydric conditions, a high water table can be at
or above the soil surface for 3 to 6 months per year.

**Appearance:** This vegetation type is characterized as a shrubland or
woodland in more mature stages. It is considered a low closed canopy of
mixed wetland shrub and tree species such as willow, wax myrtle, red
maple, and bay trees. A dense midstory and understory of wetland shrub
and tree species is present, and a sparse groundcover of aquatic herbs
may occur (Figure 10).

**Ecology:** Palustrine shrub is ecologically similar to palustrine
marsh. This is a water dependent ecosystem where the vegetation is
composed of wetland-dependent species. The water table of this
vegetation type is above the soil surface for most of the year. At times
of the year in drier periods when the water levels are not maintained by
ground water tables, levels are maintained by surface water run-off
during precipitation events. As a result of the continued presence of
water at or above the soil surface, the plant species associated with
this vegetation type are obligate wetland species requiring flooded
conditions throughout most or all of its life cycle. Alterations to the
local hydrology would significantly impact the species composition and
structure of this vegetation type. Increased water levels may promote
more deeper-water-tolerant species such as cattails, cypress, red maple,
bays, sourgum, and others. Decreased water levels may promote a
transition to more mesic or flatwoods species (e.g., sweetbay, slash
pine, and palmetto). In addition, alterations to local hydrology may
allow invasive species to colonize an area under conditions of either
increased or decreased water to a site.

Fire may influence the abundance, composition, and structure of
palustrine shrub vegetation. In the absence of fire, palustrine marsh
develops increased shrubs and woody growth into the midstory and
develops into a palustrine shrub vegetation type. This vegetation type
is more resistant to frequent fires than palustrine marshes. The fuels
are poor in this vegetation and mostly made up of incombustible
materials. Natural fire frequencies probably occur in this vegetation
type once every 5 to 10 years. Under drier conditions, fires can carry
across this vegetation type, consume and kill all vegetation present.
Like many wetland forest species, however, resprouting will occur
immediately following fires. Although fire is currently used as a
management tool to reduce woody growth in palustrine shrub vegetation,
it is unclear what the impact of different seasons of burn will have on
reducing woody growth.

**Vegetation:**

***Overstory:*** The overstory may include red maple (*Acer rubrum*),
sweetbay (*Magnolia virginiana*), sourgums (*Nyssa* spp.) red bay
(*Persea borbonia* var. *borbonia*), Carolina willow (*Salix
caroliniana*), baldcypress (*Taxodium distichum*).

***Midstory:*** The midstory can be a thicket of tall shrubs and can
include red maple (*Acer rubrum*), buttonbush (*Cephalanthus
occidentalis*), buckwheat tree (*Cliftonia monophylla*), titi (*Cyrilla
racemiflora*), huckleberries (*Gaylussacia* spp.), hollies (*Ilex* spp.)
corkwood (*Leitneria floridana*), sweetbay (*Magnolia virginiana*), wax
myrtle (*Myrica cerifera*), red bay (*Persea* *borbonia* var.
*borbonia*), swamp bay (*P. palustris*), sourgum ( *Nyssa* spp.), and
Carolina willow (*Salix caroliniana*).

***Understory:*** In addition to midstory species, the understory can
include peppervine (*Ampelopsis arborea*), St. John\'s-worts
(*Hypericum* spp.), and dewberries (*Rubus* spp.).

***Groundcover:*** There are few groundcover species present in this
vegetation type, but they may include any groundcover species that occur
in palustrine marsh.

![](media/image10.jpeg){width="6.495138888888889in"
height="4.340277777777778in"}Figure 10. Appearance of palustrine shrub
vegetation class.

***Palustrine Open Water***

**Synonyms:** Coastal dune lake, freshwater pond, *Ceratophyllum
demersum* herbaceous vegetation *Najas guadalupensis - Ceratophyllum
demersum - Utricularia inflata* herbaceous vegetation.

**Extent on Refuge:** Total acres = 5.5 acres. A description of this
vegetation type is given to describe a management goal for palustrine
open water sites if needed.

**Topography:** Low, nearly level terrain.

**Soils:** The soils of this vegetation type are similar to the soils of
palustrine marsh and shrub vegetation types and include Maurepas muck,
and Rutledge loamy fine sand. These soils are poorly drained soils of
brackish marshes and swamps. There is generally a mucky or loamy sand
within the top 8 inches of the soil surface and sands below to a depth
of 80 inches or more. These soils are fertile and contain a large amount
of organic matter.

**Hydrology:** Hydric, permanent deep to shallow standing water
throughout the year.

**Appearance:** The vegetation that makes up this cover class includes
herbaceous submergent and emergent wetland species that are confined to
the boundaries of the pond or lake. The vegetation of shorelines and
margins of palustrine open water is considered separately as either
palustrine marsh or shrub for this study (Figure 11).

**Ecology:** This is a water-dependent system. Water levels are
permanently maintained in open water ponds and lakes by the ground water
table being above the soil surface for most of the year. Water levels
are also maintained by surface water run-off into the open water sites.
Small palustrine ponds may dry out for a portion of the year. The plants
associated with this vegetation type are obligate wetland species and
provide the basis of the food chain for the fish and wildlife (e.g.
migratory birds) that live in and around open water ponds and lakes.
Most of the vegetation consists of submergent vegetation that grows
below the water surface for most of its life cycle except during
flowering. Alterations to the hydrologic regime could impact the
abundance and composition of species in open water areas. Increased
water levels may promote only deeper-water-tolerant plant species and
lower plant species diversity. Decreased water levels may promote more
shallow water species such as cattails and other palustrine marsh and
shrub species. Alterations in water levels may also promote the
introduction of invasive species such as *Salvinia* spp. and others.

This vegetation type is resistant to fire for the most part. The
vegetation is vulnerable to fire under drought conditions, or during
times when small open ponds dry up. Fires will generally ignite in
adjacent vegetation types and burn into the organic peat layers of the
ponds as they dry out. In the absence of precipitation events or a
recovery of water levels, ground peat fires may occur at the surface or
underground peat layers for a long period of time.

**Vegetation:**

***Overstory:*** none, an occasional baldcypress (*Taxodium distichum*)
tree or sourgum (*Nyssa* spp.) may occur in standing water along the
edge of the open water.

***Midstory:*** Few midstory species are present except small trees and
tall shrubs that may grow along the edge in shallow water. These species
may include red maple (*Acer rubrum*), rosemallows (*Hibiscus* spp.),
wax myrtle (*Myrica cerifera*), and Carolina willow (*Salix*
*caroliniana*).

***Understory:*** In addition to juvenile midstory species present in
the understory amaranth (*Amaranthus* spp.), and St. John\'s-worts
(*Hypericum* spp.) may occur.

***Groundcover:*** Plants growing on the edge in shallow water or in the
deeper open water may include; joyweeds (*Alternanthera* spp.), coontail
(*Ceratophyllum* *demersum*), bittercresses *(Cardamine* spp.), Jamaica
swamp sawgrass (*Cladium* *jamaicense*), flatsedges (*Cyperus* spp.),
spikerushes (*Eleocharis* spp.), marshpennyworts (*Hydrocotyle* spp.),
St. John\'s-worts (*Hypericum* spp.), rushes (*Juncus* spp.), duckweeds
(*Lemna* spp.), sprangletops (*Leptochloa* spp.), frog\'s-bit
(*Limnobium* *spongia*), marshweeds (*Limnophila* spp.), halfchaff
sedges (*Lipocarpha* spp.), primrosewillows (*Ludwigia* spp.),
watergrasses (*Luziola* spp.), waternymphs (*Najas* spp.), lotus
(*Nelumbo* spp.), pondlilies (*Nuphar* spp.), waterlilies (*Nymphaea*
spp.), goldenclub (*Orontium* *aquaticum*), royal fern (*Osmunda*
*regalis*), knotweeds (*Polygonum* spp.), rustweed (*Polypremum*
*procumbens*), pondweeds (*Potamogeton* spp.), mermaidweeds
(*Proserpinaca* spp.), beaksedges (*Rhynchospora* spp.), docks (*Rumex*
spp.), pimpernels (*Samolus* spp.), arrowheads (*Sagittaria* spp.),
bulrushes (*Scirpus* spp.), duckweeds (*Spirodela* spp.), fireflag
(*Thalia* *geniculata*), cattails (*Typha* spp.), bladderworts
(*Utricularia* spp.), vetches (*Vicia* spp.), chainferns (*Woodwardia*
spp.) yelloweyed grasses (*Xyris* spp.), and wild rice (*Zizania*
*aquatica*).

![](media/image11.jpeg){width="6.6in"
height="4.254861111111111in"}Figure 11. Appearance of palustrine open
water.

***Estuarine Marsh***

**Synonyms:** Saltwater marsh, coastal dune lake, estuarine tidal marsh,
tidal marsh, brackish marsh, coastal marsh, *Spartina patens - Juncus
roemerianus* tidal herbaceous vegetation, *Juncus roemerianus* high
marsh vegetation, *Juncus roemerianus* low marsh vegetation, *Distichlis
spicata - Spartina* spp. tidal herbaceous vegetation, *Spartina bakeri -
Spartina patens* herbaceous vegetation.

**Extent on Refuge:** Total acres = 2782.4 acres. Occurs on St. Vincent
Island, Pig Island, and the Mainland Unit. This vegetation type is found
mostly along the northeastern portion of St. Vincent Island and in
Mallard Slough marsh and Sheepshead Bayou marsh. It makes up almost one
third of the vegetation on St. Vincent Island. On Pig Island, estuarine
marsh forms a narrow strip of marsh completely around the outer edge of
the island. The largest area of estuarine marsh on Pig Island is found
in the southern portion of the island. It makes up to one third of the
vegetation of this island. On the mainland unit, estuarine marsh makes
up the vegetation of the southern half of the unit and extends into St.
Vincent Sound.

**Topography:** Low, nearly level terrain at or below sea level.

**Soils:** The soils of this vegetation type include Bohicket, Tisonia,
Dirego, and Bayvi soils. These soils are very poorly drained soils that
are made up of muck in the top surface layers with a clay or sandy
component deeper in the profile. These are generally fertile, highly
saline soils with a high organic content.

**Hydrology:** Estaurine marsh is subject to hydric conditions, flooded
once or more daily in low marsh situations to periodic flooding during
storm events and extremely high tides in high marsh situations.

**Appearance:** This vegetation type appears as a continuous layer of
salt-tolerant, herbaceous species with little to no shrubs or trees.
This vegetation class will appear as large expanses of grasses, rushes,
and sedges along coastlines (Figure 12).

**Ecology:** Estuarine marshes are, by definition, exposed to tidal
influence at least one time per day. Tides flush nutrients into and out
of marshes that act as buffers between the harsh shoreline environments
and the more upland forests and freshwater marsh environments. Primary
productivity is the highest in this ecosystem. Plants of estuarine
marshes are able to survive both saline and flooding conditions. Most
plants of this vegetation type are considered obligate wetland species
where flooded conditions or saturated soils are required for all or part
of the life cycle. Alterations of the hydrology to this vegetation type
could impact the composition of species present. Increased fresh water
into a site could convert the site to more palustrine systems.

The natural fire frequency and importance of natural fire to this
vegetation type are not well understood. Current management practices of
estuarine marshes use fire as a tool to produce young plant shoots as a
food source for migrating waterfowl and shorebirds. Fire will also
reduce woody growth into open salt marshes and maintain a grass and herb
groundcover. Fire is promoted in areas as frequent as once every year to
once every 3 years.

**Vegetation:**

***Overstory:*** This vegetation type is considered a grassland, with
few overstory species present. Cabbage palm (*Sabal palmetto*) trees may
occur infrequently throughout a site.

***Midstory:*** The midstory is sparse in this vegetation type but may
include falsewillows (*Baccharis* spp.), marshelder (*Iva* spp.), wax
myrtle (*Myrica cerifera*), which make up the majority of tall shrubs if
present.

***Understory:*** In addition to occasional midstory species, the
understory may include amaranths (*Amaranthus* spp.), saltbushes
(*Atriplex* spp.), rosemallows (*Hibiscus* spp.), saltmarsh mallows
(*Kostelezkya* spp.), and common reeds (*Phragmites* spp.).

***Groundcover:*** The groundcover may include foxgloves (*Agalinis*
spp.), milkweeds (*Asclepias* spp.), asters (*Aster* spp.),
herb-of-grace (*Bacopa* *monnieri*), saltwort (*Batis* *maritima*),
seaside oxeyes (*Borrichia* spp.), sedges (*Carex spp*.), Jamaica swamp
sawgrass (*Cladium jamaicense*), swallowworts (*Cynanchum* spp.),
flatsedges (*Cyperus* spp.), saltgrasses (*Distichlis* spp.),
spikerushes (*Eleocharis* spp.), morningglories (*Ipomoea* spp.), rushes
(*Juncus* spp.), sealavenders (*Limonium* spp.), christmasberry
(*Lycium* *carolinianum*), shoregrass (*Monanthochloe* *littoralis*),
camphorweeds (*Pluchea* spp.), pondweesd (*Potamogeton* spp.), mock
bishopsweed (*Ptilimnium* *capillaceum*), rosegentians (*Sabatia* spp.),
glassworts (*Salicornia* spp.), bulrushes (*Scirpus* spp.), rattlebox
(*Sesbania* *punicea*), seapurslanes (*Sesuvium* spp.), cordgrasses
(*Spartina* spp.), dropseeds (*Sporobolus* spp.), seepweeds (*Suaeda*
spp.), arrowgrass (*Triglochin* *striata*), cattails (*Typha* spp.),
vetches (*Vicia* spp.), cowpeas (*Vigna* spp.), and horned pondweed
(*Zannichellia* *palustris*).

![](media/image12.jpeg){width="6.5in"
height="4.208333333333333in"}Figure 12. Appearance of estaurine marsh
vegetation class.

***Estuarine Shrub***

**Synonyms:** Estuarine tidal marsh, *Baccharis halimifolia - Iva
frutescens* shrubland, *Baccharis halimifolia - Iva frutescens / Panicum
virgatum* shrubland, *Iva frutescens* / *Spartina spartinae* shrubland,
*Iva frutescens* shrubland, *Myrica cerifera - Baccharis halimifolia /
Spartina spartinae* shrubland.

**Extent on Refuge:** Total acres = 1.5 acres. Occurs on St. Vincent
Island, Pig Island, and the Mainland Unit. On St. Vincent Island, this
vegetation type is found in small areas along edges of estuarine marshes
on the northern portion of the island. On Pig Island, this vegetation
type occurs in small patches in the interior of the marsh along the
southern tip of the island. On the mainland unit, a small patch of this
vegetation type is found in the estuarine marsh on the southern end of
the unit.

**Topography:** Low, nearly level terrain, at or below sea level. This
vegetation type is slightly higher in elevation than estuarine marsh.

**Soils:** The soils of this vegetation type are similar to estuarine
marsh soils and include Bohicket, Tisonia, Dirego and Bayvi soils. These
soils are very poorly drained soils that are made up of muck in the top
surface layers with a clay or sandy component deeper in the profile.
These are generally fertile, highly saline soils with a high organic
content.

**Hydrology:** Mesic to hydric conditions, flooded once or more daily in
low marsh situations to periodic flooding during storm events and
extremely high tides in high marsh situations.

**Appearance:** This vegetation type is characterized as a shrubland.
The canopy is dominated by salt-tolerant wetland species such as marsh
elder, groundsel tree, and wax myrtle which make a thick shrub layer.
The midstory and understory of this vegetation type can be thickets of
shrub species as well. Herbaceous estuarine marsh species makeup the
groundcover if present (Figure not available).

**Ecology:** Estuarine shrub vegetation is similar in ecology to
estuarine marsh vegetation. This vegetation type is considered a more
mature area of estuarine marsh where thickets of salt-tolerant shrubs
have invaded higher elevation areas that may not be exposed to tidal
influence. The dominant shrubs of this vegetation type are not
necessarily obligate wetland species but may tolerate periodic flooding
events. Alterations of the hydrology to this vegetation type could
impact the composition of species present. Increased fresh water into a
site could convert the site to more palustrine systems.

The natural fire frequency and importance of natural fire to this
vegetation type are not well understood. Current management practices of
estuarine shrub vegetation use fire as a tool to reduce woody growth to
develop more open salt marshes and maintain a grass and herb
groundcover. Fire is promoted in areas as frequently as annually to once
every 3 years.

**Vegetation:**

***Overstory:*** similar to estuarine marsh with cabbage palm (*Sabal
palmetto*) occurring occasionally.

***Midstory:*** The midstory is more prominent in this vegetation type
and is made up of a thicket of shrubs including saltwater falsewillows
(*Baccharis* spp.), marshelders (*Iva* spp.), and wax myrtle (*Myrica
cerifera*).

***Understory:*** The understory is similar to estuarine marsh species
and includes amaranths (*Amaranthus* spp.), saltbushes (*Atriplex*
spp.), rosemallows (*Hibiscus* spp.), saltmarsh mallows (*Kostelezkya*
spp.), and common reeds (*Phragmites* spp.).

***Groundcover:*** The groundcover is similar to estuarine marsh and
includes foxgloves (*Agalinis* spp.), milkweeds (*Asclepias* spp.),
asters (*Aster* spp.), herb-of-grace (*Bacopa* *monnieri*), saltwort
(*Batis* *maritima*), seaside oxeyes (*Borrichia* spp.), sedges (*Carex
spp*.), Jamaica swamp sawgrass (*Cladium jamaicense*), swallowworts
(*Cynanchum* spp.), flatsedges (*Cyperus* spp.), saltgrasses
(*Distichlis* spp.), spikerushes (*Eleocharis* spp.), morningglories
(*Ipomoea* spp.), rushes (*Juncus* spp.), sealavenders (*Limonium*
spp.), christmasberry (*Lycium* *carolinianum*), shoregrass
(*Monanthochloe* *littoralis*), camphorweeds (*Pluchea* spp.), pondweeds
(*Potamogeton* spp.), mock bishopsweed (*Ptilimnium* *capillaceum*),
rosegentians (*Sabatia* spp.), glassworts (*Salicornia* spp.), bulrushes
(*Scirpus* spp.), rattlebox (*Sesbania* *punicea*), seapurslanes
(*Sesuvium* spp.), cordgrasses (*Spartina* spp.), dropseeds
(*Sporobulus* spp.), seepweeds (*Suaeda* spp.), arrowgrass (*Triglochin*
*striata*), cattails (*Typha* spp.), vetches (*Vicia* spp.), cowpeas
(*Vigna* spp.), and horned pondweed (*Zannichellia* *palustris*).

***Estuarine Open Water***

**Synonyms:** Coastal dune lakes, saltwater ponds, lagoons, *Ruppia,
maritima* herbaceous vegetation, *Potamogeton pectinatus - Ruppia
maritima* herbaceous vegetation*, Potamogeton* *perfoliatus* -
*Zannichellia palustris* herbaceous vegetation.

**Extent on Refuge:** Total acres = 854.2 acres. This cover type occurs
on St. Vincent Island and occurs as small saline ponds scattered in
estuarine marsh vegetation of the northern portion of the island of
Mallard Slough marsh and Sheepshead Bayou marsh.

**Topography:** Low, nearly level terrain at or below sea level.

**Soils:** The soils of this vegetation type are similar to the soils of
estuarine marshes and shrub vegetation types and include Bohicket,
Tisonia, Dirego, and Bayvi soils. These soils are very poorly drained
soils that are made up of muck in the top surface layers with a clay or
sandy component deeper in the profile. These are generally fertile,
highly saline soils with a high organic content.

**Hydrology:** Estaurine open water occurs under hydric conditions with
standing water present at high tide. Fluctuations in water levels are
dependent on tidal influence and flooding with storm events.

**Appearance:** The plants of this cover class are predominately
submersed and emergent vegetation confined to the boundaries of the
estuarine open water. The vegetation is herbaceous and mostly submergent
in deeper-water areas and emergent vegetation restricted to the margins
and edges of the ponds and lakes (Figure 14).

**Ecology:** Estuarine open water systems can be tidally influenced or
over time can be isolated into saltwater ponds and lakes that are
periodically overwashed with salt water. Salinity in this open water
system can vary greatly depending on precipitation and storm events.
Estuarine open water systems are important as breeding grounds for
organisms and stopovers for migratory birds feeding on plants within
them. The plant species that are associated with this vegetation type
are submergent, salt tolerant wetland species that are found below the
water surface most of the life cycle and above the surface during
flowering.

This vegetation type is resistant to fire for the most part. The
vegetation is vulnerable to fire under drought conditions or during
times when small open saltwater ponds dry up. Fires will generally
ignite in adjacent vegetation types and burn into the organic peat
layers of the ponds as they dry out. In the absence of precipitation
events or a recovery of water levels, ground peat fires may occur at the
surface or underground peat layers for a long period of time.

**Vegetation:**

***Overstory:*** This vegetation type is similar to estuarine marsh with
cabbage palm (*Sabal palmetto*) occurring occasionally.

***Midstory:*** Similar to estuarine shrub vegetation, the midstory
along the edge of open water may include saltwater falsewillows
(*Baccharis* spp.), marshelders (*Iva* spp.), and wax myrtles (*Myrica
cerifera*).

***Understory:*** The understory species that occur on the edge of open
water are similar to estuarine marsh species and may include amaranths
(*Amaranthus* spp.), saltbushes (*Atriplex* spp.), rosemallows
(*Hibiscus* spp.), saltmarsh mallows (*Kostelezkya* spp.), and common
reeds (*Phragmites* spp.).

***Groundcover:*** The groundcover in this vegetation type will include
submergent saltwater species such as widgeongrasses (*Ruppia* spp.), and
saltwater eel grasses (*Zostera* spp.). Emergent groundcover species in
shallow water along the margin of open water may include any species of
estuarine marsh.

![](media/image13.jpeg){width="6.6in"
height="4.254861111111111in"}Figure 13. Appearance of estaurine open
water.

***Beach Dunes***

**Synonyms:** Beach

**Extent on Refuge:** Total acres = 219.2 acres. Occurs on St. Vincent
Island. This vegetation type is found along the foredunes of high wave
active areas of the southern and eastern shorelines of the island.

**Topography:** Sand ridge tops and side slopes of sand ridges along
coastline.

**Soils**: The soil map unit that makes up the beach dunes on the refuge
is the Newhan-Corolla complex. This soil is excessively drained soil
made up of gray and white sands to a depth over 80 inches.

**Hydrology:** Excessively drained deep sands, there is no water table
within 80 inches.

**Appearance:** The vegetation of the beach dunes is sparse with no
overstory or midstory components and either a sparse to dense understory
vegetation layer (Figure 15).

**Ecology:** Beach dune vegetation occurs on the foredune or first dune
parallel to the shore. This is a harsh and dynamic environment for
plants and animals to live in. Organisms living in this environment are
subjected to high energy wave actions, heavy winds, saltwater flooding,
and constant sand deposition. As a result most plant species in this
vegetation type have specialized adaptations for procumbent growth
(i.e., spreading growth close to the ground), water conservation, salt
tolerance, and flood tolerance. There are few species that can survive
and establish over long periods of time in this dynamic environment.
There is continual movement of sand and deposition. During storm events,
foredunes can be destroyed or created in one event. The vegetation is
generally sparse on younger foredunes and more abundant on back dunes
and older sand dunes.

Fire does not play a significant role in the structure or composition of
this vegetation type. Fires will occasionally burn into beach vegetation
but due to its sparse nature will not spread over large areas.

**Vegetation:**

***Overstory:*** Very few species occur in the overstory, but they may
include red cedar (*Juniperus virginiana*), slash pine (*Pinus
elliottii*), or cabbage palm (*Sabal palmetto*).

***Midstory:*** The midstory is not prominent in this vegetation type
and may include isolated individuals of saltwater falsewillows
(*Baccharis* spp.), marshelders (*Iva* spp.), and regenerating overstory
species.

***Understory:*** The understory may include species such as saltbushes
(*Atriplex* spp.), and juveniles of midstory species.

***Groundcover:*** The groundcover is mostly barren and may include
dense areas with sandburs (*Cenchrus* spp.), buttonweeds (*Diodia*
spp.), lovegrasses (*Eragrostis* spp.), mille grains and bluets
(*Hedyotis* spp.), sunflowers (*Helianthus* spp.), marshpennyworts
(*Hydrocotyle* spp.), morningglories (*Ipomoea* spp.), lupines
(*Lupinus* spp.), eveningprimroses (*Oenothera* spp.), pricklypear cacti
(*Opuntia* spp.), panicgrasses (*Panicum* spp.), nailworts (*Paronychia*
spp.), crowngrasses (*Paspalum* spp.), fogfruits (*Phyla* spp.),
groundcherries (*Physalis* spp.), spurges (*Poinsettia* spp.), docks
(*Rumex* spp.), saltworts (*Salsola* spp.), bluestem grass
(*Schizachyrium* spp.), seaoats (*Uniola* spp.), and yuccas (*Yucca*
spp.).

![](media/image14.jpeg){width="6.49375in"
height="4.402083333333334in"}Figure 14. Appearance of beach dune
vegetation class.

**Other Cover Classes**

***Intertidal Zone***

**Synonyms:** Unconsolidated shoreline, unconsolidated substrate, beach,
tidal flat.

**Extent on Refuge:** Total acres = 263.1 acres. Occurs on St. Vincent
Island. This cover type is found between the high and low tide marks of
the high wave energy areas of the southern and eastern portions of the
island. A small amount of intertidal zone can also be found along the
northwestern tip of the island.

**Soils:** This cover class is associated with beach soil as defined by
the Franklin County soil survey map. As defined, beach as a soil unit
includes deposits of loose fine sand and shell fragments below the high
tide mark.

**Topography:** Along slopes of shorelines between low and high tide
marks.

**Hydrology:** Flooded with tides.

***Oyster Reef***

**Synonyms:** Mollusk reefs*,* oyster bed.

**Extent on Refuge:** Total acres = 36.9 acres. Occurs along the shores
of St. Vincent Island and the Mainland Unit. This cover type is found
exposed at low tide and makes extensions of land along the northeastern
tip of the island forming St. Vincent Point and along the northern
portion of the island forming Pickalene Bar. A small oyster reef is
found on the southeastern portion of the mainland unit.

**Soils:** No soils have been mapped for this class because the area is
made up of shells and shell fragments from oysters.

**Topography:** At or below sea level.

**Hydrology:** Portions of oyster reefs may be completely flooded during
high tides.

***Intertidal Flats***

**Synonyms:** Unconsolidated substrate, saltflats, mudflats, tidal
flats*.*

**Extent on Refuge:** Total acres = 5.5 acres. Occurs on St. Vincent
Island and Pig Island. On St. Vincent Island, this cover type is found
in small isolated patches of estuarine marshes of the northeastern
portion and along the northern shore of the western end of the island.
On Pig Island, this cover type is found in the southwestern portion of
the island as a small patch within the estuarine marsh.

**Soils:** This cover class is associated with beach soil as defined by
the Franklin County soil survey map (Sasser et al. 1994). As defined,
beach soils include deposits of loose fine sand and shell fragments
below the high tide mark.

**Topography:** Along slopes of shorelines between low and high tide
marks.

**Hydrology:** Flooded with tides.

***Developed***

**Synonyms:** Urban, disturbed sites.

**Extent on refuge:** Total acres identified on map =14.1 acres. There
are significant areas of disturbance to native soils throughout the
refuge including an extensive road system, home sites, clearings for
soil borrow pits, bridges, water control structures, fenced
impoundments, boat landing sites, and others. Where there is significant
disturbance to native soil (i.e., turning over of the topsoil) there
will be an opportunity for invasive species to establish on the refuge.
Most of the invasive species (see Table 5) on the refuge are limited to
disturbed and developed areas.

**Topography:** Variable.

**Soils:** Soils are variable depending on the original soil map unit
developed.

**Hydrology:** Variable, but see hydrology report to refuge by Davis and
Mokray 1999.

**Vegetation*:***

***Overstory:*** Overstory trees of disturbed sites may include
mulberries (*Morus* spp.), sweet acacias (*Acacia* spp.), and Chinese
tallows (*Sapium sebiferum*).

***Midstory:*** In addition to overstory tree species, the midstory of
disturbed sites may include saltwater falsewillows (*Baccharis* spp.),
hickories (*Carya* spp.), oaks (*Quercus* spp.), and Hercule\'s club
(*Zanthoxylum clava-herculis*).

***Understory:*** The understory of disturbed sites may include
regenerating species of the overstory and midstory as well as peppervine
(*Ampelopsis arborea*), Virginia creeper (*Parthenocissus
quinquefolia*), common reeds (*Phragmites* spp.), dewberries (*Rubus*
spp.), elderberries (*Sambucus* spp.), sensitive plants (*Senna* spp.),
rattlebox (*Sesbania punicea*), eastern poison ivy (*Toxicodendron
radicans*), and Chinese wisteria (*Wisteria sinensis*).

***Groundcover:*** The groundcover species that occupy a disturbed site
vary depending on the initial vegetation type disturbed and can include
any of the following threeseed mercuries (*Acalypha* spp.), foxgloves
(*Agalinis* spp.), amaranths (*Amaranthus* spp.), ragweeds (*Ambrosia*
spp.), bluestems (*Andropogon* spp.), threeawns (*Aristida* spp.),
carpetgrasses (*Axonopus* spp.), bittercresses (*Cardamine* spp.),
sedges (*Carex* spp.), sandburs (*Cenchrus* spp.), partridgepeas
(*Chamaecrista* spp.), sandmats (*Chamaesyce* spp.), goosefoots
(*Chenopodium* spp.), thistles (*Cirsium* spp.), dayflowers (*Commelina*
spp.), horseweeds (*Conyza* spp.), tickseeds (*Coreopsis* spp.),
rabbitbells (*Crotalaria* spp.), crotons (*Croton* spp.), bermudagrass
(*Cynodon dactylon*), flatsedges (*Cyperus* spp.), American wild carrot
(*Daucus* *pusillus*), tansymustards (*Descurainia* spp.), witchgrasses
(*Dichanthelium* spp.), crabgrasses (*Digitaria* spp.), buttonweeds
(*Diodia* spp.), barnyardgrasses (*Echinochloa* spp.), false daisy
(*Eclipta* *prostrata*), goosegrass (*Eleusine indica*), lovegrasses
(*Eragrostis* spp.), fireweed (*Erechtites* *hieracifolia*), fleabanes
(*Erigeron* spp.), eryngoes (*Eryngium* spp.), thoroughworts
(*Eupatorium* spp.), fingergrasses (*Eustachys* spp.), flattop goldenrod
(*Euthamia* *graminifolia*), fimbries (*Fimbristylis* spp.), bedstraws
(*Galium* spp.), beeblossoms (*Gaura* spp.), Carolinacranesbill
(*Geranium* *carolinianum*), everlastings (*Gnaphalium* spp.), mille
grains and bluets (*Hedyotis* spp.), heliotropes (*Heliotropium* spp.),
camphorweed (*Heterotheca* spp.), St. John\'s-worts (*Hypericum* spp.),
morningglories (*Ipomoea* spp.), dwarfdandelions (*Krigia* spp.),
japanese clover (*Kummerowia* *striata*), wild lettuces (*Lactuca*
spp.), lion\'s ear (*Leonotis* *neptifolia*), pepperweeds (*Lepidium*
spp.), sprangletops (*Leptochloa* spp.), toadflaxes (*Linaria* spp.),
watergrasses (*Luziola* spp.), christmasberry (*Lycium* *carolinianum*),
garden tomato (*Lycopersicon* *esculentum*), Japanese climbing fern
(*Lygodium japonicum*), black medick (*Medicago* *lupulina*), Carolina
bristlemallow (*Modiola* *caroliniana*), carpetweeds (*Mollugo* spp.),
beebalms (*Monarda* spp.), tropical puff (*Neptunia pubescens*),
eveningprimroses (*Oenothera* spp.), prickly pear cacti (*Opuntia*
spp.), woodsorrels (*Oxalis* spp.), panicgrasses (*Panicum* spp.),
crowngrasses (*Paspalum* spp.), golden bamboo (*Phyllostachys aurea*),
pokeweeds (*Phytolacca* spp.), plantains (*Plantago* spp.),
fire-on-the-mountain (*Poinsettia* *cyathophora*), knotweeds
(*Polygonum* spp.), rustweed (*Polypremum* *procumbens*), meadowbeauties
(*Rhexia* spp.), beaksedges (*Rhynchospora* spp.), docks (*Rumex* spp.),
soapberries (*Sapindus* spp.), bluestems (*Schizachyrium* spp.),
licoriceweed (*Scoparia* *dulcis*), foxtails (*Setaria* spp.), fanpetals
(*Sida* spp.), catchflies (*Silene* spp.), sowthistles (*Sonchus* spp.),
scaleseeds (*Spermolepis* spp.), wedgescales (*Sphenopholis* spp.),
dropseeds (*Sporobolus* spp.), tridens (*Tridens* spp.), sandgrasses
(*Triplasis* spp.), vervains (*Verbena* spp.), crownbeards (*Verbesina*
sp.), and fescue (*Vulpia* spp.).

***Managed Marsh***

The vegetation of this class will reflect the vegetation types as
defined by management and restoration activities.

**Extent on refuge:** Total acres currently identified on map is 762.6
acres. There are currently five water control structures on St. Vincent
Island. These allow the control of salt water into and out of designated
lakes, ponds, and wetlands. The areas controlled are in the southeastern
portion of the island and include Oyster Pond and Lakes 1-5. The marshes
surrounding these open water sites have been impacted by the flooding
regimes and saltwater exchange allowed in these areas. Most recently, a
significant amount of cattail (*Typha* spp.) was reduced by humans as a
result of flood management projects.

***Managed Open Water***

The vegetation of this class will reflect the vegetation types as
defined by management and restoration activities.

**Extent on refuge:** Total acres currently identified on map is 167.6
acres. There are currently five water control structures on St. Vincent
Island. These allow the control of salt water into and out of designated
lakes, ponds, and wetlands. The areas controlled are in the southeastern
portion of the island and include Oyster Pond and Lakes 1-5. The
vegetation, predominately submersed vegetation, will be impacted as
flooding regimes and salinities change with management activities.

**Summary**

This project has resulted in a current description of the vegetation
cover types for St. Vincent NWR. We have produced a base vegetation map
that can continue to be used with GIS software to build layers of
information for management purposes. As a result of this project, we
have defined 21 cover types; 15 are composed of natural vegetation, 3
are defined based on mineral components, and 3 are associated with human
activities. We have also described the ecology and flora for each
vegetation class and produced a database that can be used for plant
identification and other purposes. Nearly 600 plant species descriptions
were defined in the plant database which included not only traditional
taxonomic information, but also ecological information, native or
non-native status, wetland status, and rare plant status. In addition,
this final report has described the overall ecology of the refuge in
terms of climate, geological history, and soils to give a broader
perspective of the refuge as a whole.

The natural vegetation of St. Vincent NWR makes up the ecological
building blocks for the ecosystems and organisms that utilize the
refuge. It makes up the habitat, fuels and food base for resident
organisms such as wildlife and migratory birds. Understanding the
structure and composition of the natural vegetation patterns is the
first step to understanding the ecology of the refuge. It is hoped that
the information provided in this study will give managers of the refuge
now, and in the future, an information resource that will help them make
sound management decisions.

**Research Needs**

As with many research projects, as one question begins to be answered
many more are revealed. Below are some examples of additional plant
ecology research projects and products that might help with management
issues in the future.

\- Develop a more refined ecological map of plant communities.

\- Develop a fuels map of the refuge, reflecting condition of fuels and
successional trends.

\- Conduct an analysis of the effectiveness and efficiency of the fire
management program in terms of success / failures of management
objectives.

\- Conduct an extensive invasive species survey.

\- Conduct an analysis of the vegetation change in response to water
management programs.

\- Conduct a rare plant survey.

\- Develop studies of fire effects on native vegetation such as
wiregrass.

\- Conduct habitat quality studies for migrating waterfowl and
shorebirds.

\- Develop a vegetation monitoring program to evaluate management
practices.

\- Conduct fire effect studies on vegetation used by secretive marsh
birds and neotropical migrants.

\- Develop historical vegetation maps and investigate changes in
vegetation over time.

\- Conduct an analysis of large scale disturbances (e.g., hurricanes,
wildfires) on vegetation structure.

\- Establish long term demographic studies of forest structure.

\- Conduct an investigation of fire history and estimate natural fire
frequency for community types on the refuge.

**Acknowledgments**

We are grateful to Thom Lewis, biologist, St. Vincent NWR, whose
interest, insights, experience and support made this research possible.
We thank the management staff of St. Vincent NWR, Terry Peacock, Don
Kosin and Randy Cordray for their support and interest in this study. In
addition, we thank Charlotte Chumney, Robert and Tommy Gay, Dale Shiver,
and other members of the refuge staff for their help with logistics.
They were always willing to provide logistic support with transportation
in and around the refuge, and help provide comfortable accommodations
for us on the refuge. This research would not be possible without the
help of Brandy Wainwright and Tamara Kley of the Johnson Control World
Services. Their tireless effort in helping with field data collection
and data entry made this research project a success. We also thank
Sharon King of the Johnson Control World Services for her assistance in
plant identification and specimen collections and preparations.
Vegetation map provided by Arturo Calix of the USGS-BRD, National
Wetlands Research Center. Ann Johnson of the Florida Natural Areas
Inventory program, provided technical advice and information regarding
plant taxonomy, identification and vegetation classification. This
research was funded by the USFWS and USGS-BRD under the Research
Partnership Proposal Program and additional support was provided by the
USFWS Ecological Services, Panama City, FL.

**Literature Cited**

Anderson, L. 1986. Noteworthy plants from Florida. II. Sida 11(4):
379-384.

Anderson, L. 1987. *Boltonia apalachicolensis* (Asteraceae): a new
species from Florida. Systematic Botany 12: 133-138.

Anderson, L. 1988. Noteworthy plants from north Florida. III. Sida
13(1): 93-100.

Davis, H., and M. Mokray. 1999. Assessment of the impact of road
construction and other modifications on surface water flow at St.
Vincent National Wildlife Refuge, Franklin County, Florida. USGS Final
Report to USFWS, Apalachicola, FL.

Donohue, J.F., S. Demirpolat, and W. F. Tanner. 1990. Recent shoreline
changes, Northeastern Gulf of Mexico. Pages 51-66 *in* W. F. Tanner,
editor. Coastal Sediments and Processes, Proceedings of the Ninth
Symposium on Coastal Sedimentology, Geology Department, Florida State
University, Tallahassee, FL.

Doyle, T., and K. Krauss. 1999. The sands and sambars of St. Vincent
Island. Florida Wildlife 53(4): 22-25.

Florida Natural Areas Inventory. 1990. Guide to the natural communities
of Florida. Florida Natural Areas Inventory, Tallahassee, FL. 111 pp.

Grace, J.B. 1998. Can prescribed fire save the endangered coastal
prairie ecosystem from Chinese tallow invasion? Endangered Species
Update 15:70‑76.

McAtee, W. L. 1913. A list of plants collected on St. Vincent Island,
Florida. Proceedings of the Biological Society of Washington 26:39-52.

Robbins, L.E., and R. L. Myers. 1990. Seasonal effects of prescribed
burning in Florida: a review. Tall Timbers Research Station
Miscellaneous Publication No. 8, Tallahassee, FL.

Sasser, L.D., K.L. Monroe, and J.N. Schuster. 1994. Soil surve y of
Franklin County, Florida. US Department of Agriculture, Soil
Conservation Service, University of Florida and Florida Department of
Agriculture and Consumer Services, Gainesville. 192 pp.

Schnable, J. 1966. The evolution and development of part of the
northwest Florida coast. PhD Dissertation, Florida State University,
Tallahassee. 231 pp.

Stapor, F. 1973. Coastal sand budgets and Holocene beach ridge plain
development, northwest Florida. PhD Dissertation, Florida State
University, Tallahassee. 221 pp.

Stapor, F. W., and W. F. Tanner. 1977. Late Holocene mean sea level data
from St. Vincent Island and the shape of the late Holocene mean sea
level curve. Pages 35-68 *in* W. F. Tanner, editor, Coastal
Sedimentology, Proceedings of the Third Symposium on Coastal
Sedimentology, Geology Department, Florida State University,
Tallahassee, FL.

Thompson, D. 1970. Vegetative cover types of St. Vincent Island Refuge.
Unpublished report to St. Vincent National Wildlife Refuge,
Apalachicola, FL. 11 pp.

Wunderlin, R. P. 1997. Guide to the vascular plants of Florida.
University Press of Florida, Gainesville, FL. 806 pp.

**Appendix**

**Appendix A.** *Database of plant species of St. Vincent NWR*

A hard copy of the database has been submitted with this final report.
In addition, a digital copy of the database has been submitted with this
report.

**Appendix B.** *Digital copy of vegetation map of St. Vincent NWR.*

A digital image burned onto a CD has been submitted with this final
report.

**Appendix C.** *Digital copy of the final report*.

An electronic copy of the final report is submitted with this report.