Kitchens, Wiley M.

Zweig, Christa L.

English

Aquatic Commons

  
SWS Research Brief 
No. 2009-0001 June 2009 
Defining the Present Before Restoring the 
Past:  Everglades Vegetation Communities 
Background 
The Florida Everglades, one of the largest 
relatively intact wetands in the world, is 
the largest restoration project in the world.   
The goal of Everglades restoration is to 
return the area to a more natural state by 
reestablishing approximate historic water 
quantity, quality, and timing, while still 
providing flood control and water storage 
for south Florida (http://
www.evergladesplan.org).  An important 
indicator of restoration success will be the 
response of vegetation communities 
(groups of plant species) to the proposed 
hydrologic alternatives.  A project of this 
size requires a substantial amount of infor-
mation about the plant communities and 
environmental factors shape them to guide 
the path of restoration.  
The Everglades is especially hard to define 
because of the incredible diversity of plant 
communities within relatively small areas.  
One acre of land could hold up to 10 dif-
ferent communities, each providing a par-
ticular service to the animals living there.   
Despite the extent of environmental moni-
toring that has been done in the Ever-
glades, it is difficult to pinpoint direct 
causes of plant community changes over 
such a large area.   Defining large areas of 
plant communities can be difficult and 
incredibly time consuming.  One of the last 
landscape-level inventories of communi-
ties was performed in 1959 by Loveless 
and water management strategies have 
changed considerably since that time. 
Study Goal 
We believe the vegetation in this region 
has shifted from that described by Love-
less to vegetation types formed by the pre-
sent deeper water depths, and that identify-
ing the current communities— and specific 
hydrologic variables that affect them—is 
the initial step needed before restoring 
vegetation of the past.  We defined the 
existing vegetation communities of a cen-
tral, impounded Everglades remnant, de-
scribed how both present and historic hy-
drology affect these communities, and 
documented the change from communities 
described in previous studies.  This pro-
vides baseline knowledge for Everglades 
restoration. 
Study Area 
Our study area was a portion of the Ever-
glades in the peninsular region of Florida, 
USA. The Everglades used to be one con-
tinuous wetland from Lake Okeechobee to 
Florida Bay.  Water would flow very 
slowly (sheetflow) across the landscape at 
a rate of  3-5cm/second.  It has now been 
compartmentalized by canals and levees to 
reduce flooding and to provide water for 
the cities of south Florida.   
Water Conservation Area 3A (WCA 3A) is 
the largest remnant of the original Ever-
glades, approximately 200,000 ha (Figure 
1). Our study area, the southern half of 3A 
(3AS), is a matrix of tree islands, sawgrass 
strands, and sloughs (Figure 2).  Water 
Conservation Area 3AS is the main focus 
of Everglades restoration for the next 30 
years.   
The Decompartmentalization and Sheet-
flow Enhancement Project (DECOMP—
http://www.evergladesplan.org/pm/
projects/proj_12_wca3_1.aspx) will elimi-
nate much of the levee and canal system 
that now restricts sheetflow in these areas.  
 
Page 1  
S   O   C   I   E   T   Y       O   F       W   E   T   L   A   N   D       S   C   I   E   N   T   I   S   T   S 
Figure 1:  A satellite view of south Flor-
ida and the Everglades with Water con-
servation Area 3A South outlined in yel-
low. 
Figure 2:  An example of open water 
sloughs fringed by dense sawgrass 
strands.  Small tree islands are visible in 
the background. 
SWS Research Brief No. 2009-0001 
  
Page 2  
“PR E V I O U S  S T U D I E S  O F  V E G E TAT I O N  A R E  N O  L O N G E R  
R E S P R E S E N TAT I V E  O F  C U R R E N T  C O M M U N I T I E S”  
The Florida Snail Kite  
This vegetation work has been done as part 
of a larger project monitoring the Florida 
Snail Kite, an endangered bird species, 
and its habitat.  The Snail Kite was one of 
the first species listed in the Endangered 
Species Act in the 1960s.  It has a very 
specific range from the Kissimmee Chain 
of Lakes to the Everglades.  Most recently, 
their population was hit by a severe 
drought in 2001, and numbers have contin-
ued to decline.  This may be due, in part, to 
flooding of their preferred nesting and 
foraging habitat within southern Water 
Conservation Area 3A and other major 
habitat alterations within their range. 
They are monitored with a combination of 
radio tracking and mark-resighting tech-
niques to esti-
mate popula-
tion size and 
reproductive 
success.  The 
population 
has halved 
each year 
since 2006 
and is down to 
a record low 
of approxi-
mately 700 
birds.  Func-
tional extinc-
tion is expected in 50 years with a ‘best 
case’ scenario.  The Snail Kite’s fate is 
tightly intertwined with that of the Ever-
glades and restoration actions are of great 
importance. 
S   O   C   I   E   T   Y       O   F       W   E   T   L   A   N   D       S   C   I   E   N   T   I   S   T   S 
Approximately 70% of the eastern levees 
and canals in 3AS will be removed, and 
the highway which forms the southern 
barrier will be raised to restore natural 
flow. This is an area that will see radical 
hydrologic changes in the future and is a 
critical region for restoration monitoring. 
Methods 
Vegetation for this analysis was sampled 
from 2002-2005 within 20 plots in 3AS.  
Vegetation was cut along transects (Figure 
3) that ran from one previously identified 
type (slough, sawgrass, or wet prairie) into 
another type.  The samples were sorted to 
species in a lab and dried and weighed to 
provide biomass measures.  We took over 
10,000 quarter-meter-squared samples, 
which, if lined up end to end, would stretch 
the length of 250 football fields. 
We defined vegetation communities by the 
amount and type of species present, and 
linked them to water levels at each site. 
We also separated samples into the three 
different vegetation types (slough, saw-
grass, wet prairie) and did an identical 
analysis.  This was to reduce the noise as-
sociated with grouping very different types 
together and get a more refined idea of 
communities and hydrologic/community 
relationships. 
Findings 
There were ten communities within 3AS 
(Figure 4):  shrub island, deteriorated is-
land, sawgrass, cattail, strand/slough tran-
sition, wet prairie, shallow peat prairie, 
Figure 3:  Vegetation sampling on a 
transect in 3AS     
Figure 4:  Community analysis flowchart.  Grey boxes are final 10 communities.  
SWS Research Brief No. 2009-0001 
  
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“We must have sufficient information 
about where we are now to know where we 
can go from here.” 
shallow peat wet prairie, slough, and 
deeper slough.  Communities are not nec-
essarily differentiated from one another by 
absence or presence of a species, but by 
the proportion of species present.  Sloughs 
(dominated by lilies and submerged 
aquatic plants) are the deepest community, 
followed by wet prairies (beakrush and 
maidencane communities).  Slough/strand 
transitions (dominated by lemon bacopa) 
are less deep than prairies and sawgrass, 
cattail, and deteriorated islands are more 
dry.  Shrub islands (dominated by button-
bush and pickerelweed) are the driest com-
munities in our study area.  Determinants 
of community composition included peat 
depth and water depths up to 5 years    
previous to when the sample was taken.  
This indicates that there is a lag between 
hydrologic events and the plant’s response 
to them.  Some species react more quickly 
than others with sawgrass being one of the 
slowest to respond. 
From the separate analysis, sawgrass com-
munities were influenced by water depths 
in the dry seasons up to 4 years previous to 
the sample.  Sloughs were influenced by 
both the wet and dry seasons up to 5 years 
before, and wet prairies were influenced by 
water depths in the wet season only. 
Vegetation Communities:  Past, Pre-
sent, and Future 
The communities we encountered within 
3AS were quite different than those de-
scribed by Loveless in 1959—some had 
disappeared completely.  Instead of being 
dominated by beakrush and maidencane, 
the wet prairies in our study area were 
characterized by spikerush and egyptian 
paspalidum, which can be considered 
deeper water species.  The three sawgrass 
communities that Loveless observed are 
not as evident now, with the woody spe-
cies he mentions within them, wax myrtle 
and dahoon holly, being completely absent 
from our study sites. 
Significance 
This research provides a technique to ex-
plore subtle changes in community states 
and link them to hydrologic data. 
The communities and correlating hydro-
logic gradients described in this analysis 
could be used in future management deci-
sions for 3AS. 
We also provide a snapshot of vegetation 
communities of a remnant of the Ever-
glades in present-day conditions.  It is im-
portant to have a solid foundation of where 
restoration will begin to better understand 
where we are going. 
 
S   O   C   I   E   T   Y       O   F       W   E   T   L   A   N   D       S   C   I   E   N   T   I   S   T   S 
Figure 5:  Picture of a transect through 
a slough into sawgrass vegetation. 
Figure 6:  Slough community with a  
spider lily in the foreground 
Figure 6:  Early morning on a transect 
in the Everglades 
SWS Research Brief No. 2009-0001 
  
Additional Information 
 
Zweig, C. L. and W. M. Kitchens. 2008. Effects of land-
scape gradients on wetland vegetation communities:  In-
formation for large-scale restoration.  Wetlands 28: 1086-
1096.  
 
Loveless, C. M.  1959.  A study of the vegetation of the Florida Ever-
glades.  Ecology 40:1-9.   
 
Acknowledgments:  Melissa DeSa, U. S. Army Corps of Engineers 
Use of this Document 
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Page 4  
About the Author(s): 
 
Wiley M. Kitchens is Assistant Unit Leader at the Florida Cooperative Fish and Wild-
life Research Unit, University of Florida.  His research has an emphasis on conservation 
and restoration of wetland ecosystems.  Recently, his work focuses on the endangered 
Florida Snail Kite and its habitat. 
 
Christa L. Zweig is a post-doctoral associate at the Florida Cooperative Fish and Wild-
life Research Unit, University of Florida.  Her current research focuses on plant/
hydrology relationships, wetland restoration, and the use of remote sensing in ecology.  
She tends to her dogs, cat, chickens, orchids, hot peppers, and heirloom garden in her 
spare time. 
 
Contact Information:  czweig@ufl.edu, Box 110485, Gainesville, FL 32611-0485 
For more information 
about the SWS Research 
Brief, contact: 
 
Karen L. McKee 
karenmckee1@me.com 
S   O   C   I   E   T   Y       O   F       W   E   T   L   A   N   D       S   C   I   E   N   T   I   S   T   S 
SWS Research Brief No. 2009-0001 


Defining the Present Before Restoring the Past: Everglades Vegetation Communities

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Defining the Present Before Restoring the Past: Everglades Vegetation Communities

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