Draft Final Report Deliverable 8. Tree Island Hydrology and Ecology Project

Transcription

1 Draft Final Report Deliverable 8 For Tree Island Hydrology and Ecology Project Prepared for South Florida Water Management District Skees Road West Palm Beach, FL December 29, 2006 Prepared by Dr. Mary Ann Furedi Dr. John C. Volin Florida Atlantic University 2912 College Avenue Davie, FL 33314

2 Abstract The following is the draft final report for the Tree Island Hydrology and Ecology Project in Water Conservation Area (WCA) 3A and 3B. The overall objective of this project was to obtain annual hydrological data for up to 600 tree islands in WCA-3A and 3B. Over a 17 month period, hydrological data was collected for 200 islands, 175 in 3A and 25 in 3B. Hydrological data collected on the tree islands was linked to water surface height at known benchmarks to determine the absolute height of tree islands. This project was necessary to carry out one part of the Restoration, Coordination and Verification (RECOVER) program, which was established to implement the monitoring and adaptive assessment program for the Comprehensive Everglades Restoration Plan (CERP). In particular, the Monitoring and Assessment Plan (MAP) has been established as a tool for RECOVER to assess the success of CERP implementation through a series of performance measures representative of the natural and human systems found in South Florida. The statement of work described below is intended to support the Greater Everglades Wetland module of MAP and is directly linked to the Ridge and Slough Landscape Sustainability monitoring and research component. Introduction Tree islands are a unique and important component of the Everglades landscape (Loveless, 1959; Dineen, 1974; Zaffke, 1983). Tree islands support high plant species diversity, provide nesting habitat for a variety of fauna associated to forested wetlands, and serve as wetseason refuges for upland animals such as white-tailed deer (Loveless and Ligas, 1959). Although tree islands only compose 5-10% of the total area in the Everglades (Schneider, 1966), this small portion of the Everglades landscape supports more species of flora and fauna than any other habitat (Gawlik and Rocque, 1998). Tree islands are complex and diverse forest ecosystems that comprise a variety of plant communities associated with different hydroperiods, climatic regions, soils and salinities (Armentano et al., 2003). The elevation of tree islands are usually m higher than the surrounding wetlands (Loveless, 1959); however, some islands rise as much as 1.5 m or more above the marsh, particularly tree islands located in Everglades National Park (Heisler et al., 2001). Changes in surface elevation, which are extremely gradual, are associated with gradients in vegetation, especially along the long axis of the many teardrop shaped islands of Central Everglades (Sklar and van der Valk 2002). Thus, relatively small changes in water depths and durations can produce distinct shifts in island hydroperiods, which in turn determine vegetation communities, health and sustainability of tree islands (McPherson, 1973). Although the size of tree islands can range from less than one acre to as large as several hundred acres, the proportion of an island that is relatively elevated (i.e., more than 0.5 m above the surrounding marsh) is typically less than 0.1 ha (Heisler et al., 2001). Thus, changes in water depth may profoundly affect the spatial extent of the shorter hydroperiod, drier portions of tree islands that provide scarce habitat for less flood-tolerant plants and animals. Tree islands in the central Everglades have been dramatically altered by hydrologic changes during the past century. Drought, wildfire and prolonged flooding of islands have been reported to be the principal sources of damage to island vegetation and soils (Loveless, 1959; Dineen, 1972; McPherson, 1973; Schortemeyer, 1980; Guerra, 1996). Accordingly, because of 2

3 the high water conditions that have occurred in Water Conservation Area 2A (WCA-2A), more than 85% of islands were reported to have disappeared between 1950 and 1970 (Dineen, 1974; Wu et al., 2003). Similarly, in Water Conservation Areas 3A and 3B (WCA-3A and WCA-3B), the spatial extent of tree islands decreased by more than 60% between 1940 and 1995 (Sklar and van der Valk 2002). Restoration of degraded tree islands and protection of intact islands are among the goals for restoration of the Everglades ridge and slough ecosystem. Current restoration plans predict dramatic changes in depth patterns over portions of the ridge and slough landscape having large numbers of tree islands. Thus, topographic differences across a broad spectrum of tree islands are needed to predict the effects of proposed hydrologic changes on island species composition, hydroperiod, health, and spatial extent. Predicting effects of changes in water depths and hydroperiods on tree islands or managing water to restore tree islands can not be accomplished until the spatial distribution of the different types and sizes of islands are better known. Methods Tree Island Identification The locations of tree islands in relation to the benchmarks established by the FDEP and SFWMD were determined using geo-rectified aerial photographs (Table 1; Figure 1). Tree islands were classified based on polygon area determined using Arcview software. In consultation with the SFWMD project manager, we classified tree islands into three different size classes, representing small ( ha), medium (> ha), and large (>8.0 ha) size classes. All size classes were represented in the islands selected for hydrological measurements. To identify tree islands, the islands were named first by the WCA where they were located, then by the benchmark that they were associated with and finally, by the number corresponding to the order in which they were visited for measurements. For example: tree island 3A-3-1 is located in WCA 3A, is associated with benchmark 3, and was the first island where hydrological measurements were made for those islands corresponding to benchmark 3. Hydrological Data The collection of hydrological data necessary for determination of tree island elevation required a three-step procedure. First, the benchmark associated with the tree island of interest was located and the distance from the benchmark to the water surface was measured to the nearest mm. Next, a water depth measurement (measured to the nearest mm) was taken at a temporary benchmark established at the edge of the tree island adjacent to the island head. The edge of a tree island was defined as the transition area between Salix caroliniana and Cephalanthus occidentalis dominated community and Cladium jamaicense dominated community. The geo-referenced location of each sampled island was also recorded at the time of measurement. Once the benchmark measurements (permanent and temporary) were recorded, a total of nine measurements of surface or ground water were taken at the head of the tree island (Figure 2). 3

4 The first measurement occurred at what was considered to be the center of the head of the tree island based on a combination of canopy height and surface or ground water depth. Under wet season conditions when lower lying portions of an island may be flooded, the head of an island was determined using highest canopy height and presence of dry land. In the absence of dry land, canopy height along with surface water depths were used to determine the location of the tree island head. Under dry season conditions when receding water levels expose more dry land, canopy height was the primary guide for determining the head of a tree island. Once the general area of highest canopy height was identified, random ground water measurements were made to determine the area of highest elevation and center of the island head. From the center point, random angles and distances (determined a priori) were used to determine the location of the remaining eight surface or ground water measurements (Figure 2). If the head of the island was inundated, surface water was measured using a weighted measuring rod to the nearest mm. If no standing water was visible, a small diameter soil core was removed from the tree island floor. The defect caused by the soil core was left for at least 24h after the initial coring to allow for equilibration with the surrounding marsh. After at least 24h, the soil core defects were revisited and the ground water surface to the soil surface was measured to the nearest mm. The locations of all points were geo-referenced using a Garmin GPS unit (E-trec Legend model) and all measurements were made in the early morning before water levels were affected by evapotranspiration from the vegetation. Calculation of Tree Island Height Several calculations were used to determine absolute tree island height. First, the height of the water surface at the benchmark (H W ) was calculated using the following equation: H W = H B + B W where H B (NAVD 88, m) is the known height of the benchmark and B W (m) is the depth of water above or below the benchmark. Based on the assumption that the water surface is flat within a three mile radius of the benchmark, we then used the following equation to calculate absolute tree island height (H TI ): H TI = H W - TI W where TI W (m) is either the surface water depth (positive water depth) or ground water depth (negative water depth) on the tree island. One-way analysis of variances (ANOVA) was used to determine if differences in height existed between compartments. Regression analyses were used to examine the relationships between tree island height and tree island area within compartments. Verification of Methods To test the repeatability of our calculations of absolute tree island height, we selected 10 islands, seven from WCA-3A and three from WCA-3B. In addition to the original set of hydrological measurements used to determine absolute tree island height, hydrological 4

5 measurements were collected on two other separate occasions, using the same angles and distances as were used for the first measurements. Using the three sets of hydrological measurements, absolute heights for each island were calculated and compared (Table 2). The repeated absolute height measurements for each island did not differ significantly. Overall, absolute island height only differed by a few centimeters for each island (Table 2) thus providing a level of confidence about the repeatability of the methods employed in this study. Vegetation Assessment A qualitative assessment of tree/shrub species and herbaceous species within a 1m radius of each of the nine hydrology points was recorded for each tree island. A species list was compiled for each of the nine points on each island. If invasive or endangered plants or animals were encountered while collecting hydrological data, their location was geo-referenced using a Garmin GPS unit. Results and Discussion Absolute Island Height Over a 17 month period, hydrological data was collected for 200 tree islands, 175 in central and southern WCA-3A and 25 in WCA-3B (Table 3; Figure 2). Overall, tree islands ranged in height from 1.51m to 3.38m (Table 4). Mean tree island height differed significantly between WCAs (ANOVA, p<0.0001). On average, tree islands were lower in WCA-3B than in WCA-3A (2.05m vs. 2.74m). However, this difference in height was not an effect of island size (area). Overall, there was no relationship between tree island height and tree island area (R 2 = 0.003). The same pattern was seen when WCAs were examined separately (3A R 2 = 0.092, 3B R 2 = 0.016). Although tree islands in WCA-3A were higher, the mean island area was significantly less than WCA-3B (p = 0.035) (12.73m vs m). For the purpose of this report, we focused solely on examining the absolute height of tree islands. However, we are currently preparing a paper (for submission to Restoration Ecology) that will examine the relationships between tree island height, the height of surrounding sloughs, and annual hydroperiod in the context of possible changes that can occur under CERP. The draft version of the paper will be completed by the end of January 2007 and forwarded to Carlos Coranado-Molina and Fred Sklar for review. Vegetation Assessment Throughout both WCAs, the most common dominant canopy/shrub species on tree island heads were: Annona glabra, Myrica cerifera, Persia borbonia, and Salix caroliniana (Table 5). Moving south through the WCAs, additional tropical hammock species were present such as Chrysobalanus icaco and Magnolia virginiana. For those islands located on the western border of WCA-3A, Taxodium distichum was the dominant canopy species encompassing the islands. A common flood intolerant species found on the head of tree islands was Ficus aurea. The presence of F. aurea usually indicated a high point in the island s topography. Another flood 5

6 intolerant species that was found on a few of the higher islands was Bursera simaruba. A common shrub species found in the fringe of most tree islands was Cephalanthus occidentalis. Fern species such as Acrostichum spp., Blechnum serrulatum, Osmunda regalis, and Thelypteris spp. dominated the herbaceous layer of most tree islands (Table 5). Other dominant herbaceous species included: Boehmeria cylindrical, Pontederia cordata, and Saururus cernuus. Commonly occurring vine species included: Ampelopsis arborea, Ipomea spp., Parthenocissus quinquefolia, and Vitis spp. In addition to documenting dominant canopy, shrub, and herbaceous species on the tree islands included in this study, we also recorded all invasive and non-native species that were encountered while collecting hydrological data. Included in this list are: Carica papaya, Lygodium microphyllum, Melaluca quinquenervia, Musa x paradisiacal, Paratachardina lobata, Psidium guajava, and Schinus terebinthifolius (Table 6). Of all the invasive and non-native species found on the tree islands, P. lobata, was by far the most common (52% of the islands included in this study were infested with P. lobata). Challenges and Recommendations A large challenge encountered during the course of this project was hydrological differences due to seasonality. This project began in the wet season when water levels were above normal and most tree islands were flooded, creating ideal conditions for gathering hydrological data. However, dry season conditions created new challenges for measuring hydrological differences on tree islands. First, our method for determining the area of highest elevation on a tree island became more difficult. Under wet season conditions when lower lying portions of an island may be flooded, the head of an island was determined using highest canopy height and presence of dry land. In the absence of dry land, canopy height along with surface water depths was used to determine the location of the tree island head. Under dry season conditions when receding water levels expose more dry land, canopy height was the primary guide for determining the head of a tree island. However, Hurricane Wilma caused windfall to large trees on some of the islands, making visual determination of canopy height difficult. To overcome the lack of visual references, we often had to spend several hours locating what we considered to be the highest point. Once the general high area was identified and before we could create soil cores for our nine random points, we had to first remove soil cores to determine the area of highest elevation and center of the island head. Often times this process was timely. Soils may have been compacted due to occupation of the island or we may have encountered bedrock before encountering groundwater. If bedrock was encountered, the location of the island was noted and may have been revisited under more optimal conditions. Third, the seasonal dry down of the Everglades system limited our access to workable areas. During the months of June and July most of our work was focused on islands associated with benchmark 28 since this area was still accessible by a slick-bottomed airboat. If this project is continued in the future, those involved should consider seasonal changes to the Everglades system when planning their work schedule. Several challenges involved the placement of the permanent benchmarks. During the course of the project, we visited 27 of the 31 benchmarks. With the exception of benchmark 9, 6

7 all benchmarks were in the locations provided to us. However, benchmark 9 was located over a mile west of the original GPS coordinates (Table 1 contains the corrected coordinates for benchmark 9). Some of the benchmarks were difficult to access based on their locations adjacent to highly vegetated ridges. Most of the difficulties occurred in WCA-3B where the sloughs are degraded and the overabundance of Typha latifolia makes ridge jumping challenging. If the benchmarks and associated islands in WCA-3B are revisited in the future, it would probably best to plan this work during the rainy season when all areas are accessible. Another challenge associated with the benchmark was the construction of some benchmarks. On at least six of the benchmarks, the bar designating the actual known elevation was crocked. Depending on where you measured from the bar, the water depth measurement could differ by several centimeters. If possible, it may be important to recalibrate benchmarks over time in case additional settling occurs. Another suggestion associated with the benchmarks would be that if future tree island work is done using these benchmarks, it is probably necessary to establish additional benchmarks in WCA-3A. Many of the islands on the western edge are beyond the three mile radius of the nearest benchmark thus eliminating them based on the current methods employed in this study. Additional benchmarks are needed to develop an all inclusive picture of tree island height in central and southern WCA-3A. The number of benchmarks in WCA-3B were adequate. 7

8 Literature Cited Armentano, T. V., D. T. Jones, M. S. Ross, and B. W. Gamble Vegetation Pattern and Process in Tree Islands of the Southern Everglades and Adjacent Areas. In: Sklar, F. and van der Valk, A. eds. Tree Islands of the Everglades. Boston, MA: Kluwer Academic Publishers, chapter 8. Dineen, J. W Examination of Water Management Alternatives in Conservation Area 2A: In Depth Report (South Florida Water Management District), 2(3):1-10. Gawlick, D. E. and D. A. Rocque Avain communities in bayheads, willowheads and sawgrass marshes of the central Everglades. Wilson Bulletin, 110: Guerra, R. E Imapcts of the high water period of on tree islands in Water Conservation Areas. In: Armentano, T. V. ed. Proceddings of the Conference: Ecological Assessment of the High Water Conditions in the Southern Everglades. pp Heisler, I. L., D. T. Towles, L. A. Brandt, and R. T. Pace Tree island vegetation and water management in the central Everglades. In; Sklar, F. H. and van der Valk, A. eds. Tree Islands of the Everglades. Boston MA: Kluwer Academic Publishers, chapter 5. Loveless, C. M A study of the vegetation in the Florida Everglades. Ecology 40: 1-9. Loveless, C. M. and F. J. Ligas Range conditions, life history, and food habits of the Everglades deer herd: North American Wildlife Conference Transactions, 24: McPherson, B. F Vegetation in relation to water depth in Conservation Area 3, Florida. United States Geological Survey Florida Open File Report No Schortemeyer, J. L An evaluation of water management practices for optimum wildlife benefits in Conservation Area 3A. Tallahassee, FL: Florida Game and Fresh Water Fish Commision. Schneider, W. E Water and the Everglades. Natural History Magazine 75: Sklar, F. H. and A. G. van der Valk Tree Islands of the Everglades: An Overview. pp In; Sklar, F. H. and van der Valk, A. eds. Tree Islands of the Everglades. Boston MA: Kluwer Academic Publishers, chapter 1. Wu, Y., F. H. Sklar, K. Rutchey, W. Guan, and L. Vilchek Spatial Simulations of Tree Islands for Everglades Restoration. In; Sklar, F. H. and van der Valk, A. eds. Tree Islands of the Everglades. Boston MA: Kluwer Academic Publishers, chapter 16. 8

9 Zaffke, M Plant communities of Water Conservation Area 3A: Base-Line Documentation Prior to the Operation of S-339 and S-340. West Palm Beach, FL: South Florida Water Management District. Technical Memorandum

10 Table 1. The location (NAD33, decimal degrees) and elevation (NADV88, meters) of permanent benchmarks in central and southern WCA-3A and 3B. Benchmark ID GPS Location (NAD83, decimal degrees) Latitude Longitude Elevation (NAVD88, meters)

11 Table 2. A comparison of absolute height calculations for tree islands (NADV88, meters). The hydrological data necessary for calculating absolute height was gathered on three separate occasions as a means of critiquing the accuracy of the method used to calculate tree island height. Tree Island ID Height Calculation 1 Height Calculation 2 Height Calculation 3 3A B B B A A A A A A

12 Table 3. The location of tree islands in central and southern WCA-3A and 3B where hydrological data was collected along with the date when the data collection occurred. GPS Location (NAD83, decimal degrees) Tree Island ID Date Completed Latitude Longitude 3A-4-1 8/8/ A-4-2 8/8/ A-4-3 8/8/ A-4-4 8/8/ A-4-5 8/9/ A-3-1 8/11/ A-3-2 8/11/ A-3-3 8/11/ A-3-4 8/16/ A-3-5 8/16/ A-3-6 8/18/ A-3-7 8/16/ A-3-8 8/17/ A-3-9 8/17/ A /18/ A /22/ A /22/ A /24/ A /30/ A /30/ A /30/ A /29/ A /31/ B /26/ B /23/ B /23/ B /23/ B /23/ B /26/ B /27/ B /26/ B /27/ B /28/ B /27/ B /29/ B /29/ B /29/ B /29/

13 Table 3. cont. GPS Location (NAD83, decimal degrees) Tree Island ID Date Completed Latitude Longitude 3B /11/ B /13/ B /13/ B /13/ B /10/ B /18/ A /18/ A /3/ A /7/ A /7/ B /7/ B /8/ B /8/ A /10/ A /9/ A /9/ A /9/ A /16/ A /16/ A /21/ A /22/ A /23/ B /28/ A /29/ A /30/ A /1/ A /1/ A /1/ A /5/ A /5/ A /6/ A /6/ A /7/ A /8/ A /8/ A /13/ A /19/ A /19/

14 Table 3. cont. GPS Location (NAD83, decimal degrees) Tree Island ID Date Completed Latitude Longitude 3A /20/ A /22/ A /28/ A /28/ A /27/ A /27/ A /28/ A /29/ A /29/ A /29/ A /4/ A /5/ A /4/ A /5/ A /9/ A /9/ A /10/ A /10/ A /10/ A /10/ A /11/ A /12/ A /12/ A /12/ A /23/ A /23/ A /25/ A /25/ A /26/ A /30/ A /2/ A /9/ A /7/ A /13/ A /15/ A /16/ A /27/ A /21/

15 Table 3. cont. GPS Location (NAD83, decimal degrees) Tree Island ID Date Completed Latitude Longitude 3A /27/ A /2/ A /8/ A /8/ A /8/ A /14/ A /15/ A /15/ A-9-1 3/20/ A-9-2 3/20/ A-9-3 3/22/ A-9-4 3/28/ A /28/ A /28/ A /27/ A /30/ A /30/ A /5/ A /6/ A /10/ A /19/ A /19/ A /20/ A /21/ A /21/ A /27/ A /27/ A /28/ A /5/ A /29/ A /10/ A /11/ A /26/ A /26/ A /6/ A /11/ A /11/ A-4-6 7/17/

16 Table 3. cont. GPS Location (NAD83, decimal degrees) Tree Island ID Date Completed Latitude Longitude 3A-4-7 7/19/ A-4-8 8/3/ A /2/ A-9-5 9/19/ A-9-6 9/19/ A-9-7 9/19/ A-9-8 9/19/ A-9-9 9/19/ A /25/ A /21/ A /25/ A /25/ A /26/ A /27/ A /26/ A /27/ A /28/ A /2/ A /4/ A /4/ A /9/ A /5/ A /10/ A /10/ A /11/ A /12/ A /16/ A /19/ A /18/ A /19/ A /23/ A /26/ A /26/ A /30/ A /26/ A /26/ A /26/ A /31/ A /31/

17 Table 3. cont. GPS Location (NAD83, decimal degrees) Tree Island ID Date Completed Latitude Longitude 3A /1/ A /1/ A /2/ A /2/ A /6/ A /6/ A /7/ A /7/

18 Table 4. A comparison of water surface height at the permanent benchmark and absolute height of tree islands in central and southern WCA-3A and 3B (+/- 1 SE). The units for height are: NAVD88, meters. Tree Island ID Water Height at Bench Absolute Tree Island Height SE 3A A A A A A A A A A A A A A A A A A A A A A A B B B B B B B B B B B B

19 Table 4. cont. Tree Island ID Water Height at Bench Absolute Tree Island Height SE 3B B B B B B B B B A A A A B B B A A A A A A A A A B A A A A A A A A A

20 Table 4. cont. Tree Island ID Water Height at Bench Absolute Tree Island Height SE 3A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A

21 Table 4. cont. Tree Island ID Water Height at Bench Absolute Tree Island Height SE 3A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A

22 Table 4. cont. Tree Island ID Water Height at Bench Absolute Tree Island Height SE 3A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A

23 Table 4. cont. Tree Island ID Water Height at Bench Absolute Tree Island Height SE 3A A A A A A A A A A A A A A A A A A A A A A A A

24 Table 5. The dominant tree, shrub, and herbaceous species found on the heads of tree islands in central and southern WCA-3A and 3B. Tree Island ID Dominant Canopy/Shrub Dominant Herbaceous 3A-4-1 Ficus aurea Stenotaphrum secundatum 3A-4-2 Ficus aurea Stenotaphrum secundatum 3A-4-3 3A-4-4 3A-4-5 Salix caroliniana, Myrica cerifera Ficus aurea, Myrica cerifera, Salix caroliniana Annona glabra, Salix caroliniana Stenotaphrum secundatum Osmunda regalis, Thelypteris interrupta, Boehmeria cylindrical Acrostichum spp., Blechnum serrulatum, Thelypteris interrupta 3A-3-1 Celtis occidentalis Boehmeria cylindrical 3A-3-2 3A-3-3 3A-3-4 Persea borbonia, Annona glabra, Myrica cerifera, Salix caroliniana Persea borbonia, Annona glabra, Myrica cerifera, Salix caroliniana Salix caroliniana, Myrica cerifera Boehmeria cylindrical, Osmunda regalis, Thelypteris interrupta Boehmeria cylindrical, Osmunda regalis, Thelypteris interrupta Osmunda regalis, Thelypteris interrupta, Blechnum serrulatum 3A-3-5 Salix caroliniana Blechnum serrulatum, Acrostichum spp. 3A-3-6 3A-3-7 3A-3-8 Persea borbonia, Myrica cerifera, Annona glabra Persea borbonia, Myrica cerifera, Annona glabra, Ficus aurea Annona glabra, Persea borbonia, Myrica cerifera Blechnum serrulatum, Acrostichum spp., Boehmeria cylindrical Boehmeria cylindrical, Osmunda regalis, Thelypteris interrupta Blechnum serrulatum, Acrostichum spp., Boehmeria cylindrical 24

25 Table 5. cont. Tree Island ID 3A-3-9 3A-3-10 Dominant Canopy/Shrub Persea borbonia, Myrica cerifera, Ficus aurea Annona glabra, Myrica cerifera, Salix caroliniana Dominant Herbaceous Acrostichum spp. Osmunda regalis, Thelypteris interrupta, Boehmeria cylindrical 3A-3-11 Annona glabra, Myrica cerifera Osmunda regalis, Thelypteris interrupta, Blechnum serrulatum 3A-3-12 Annona glabra, Salix caroliniana, Myrica cerifera Osmunda regalis, Thelypteris interrupt, Boehmeria cylindrical 3A-3-13 Annona glabra, Myrica cerifera Boehmeria cylindrical, Osmunda regalis 3A A-3-15 Persea borbonia, Myrica cerifera Annona glabra, Salix caroliniana, Myrica cerifera Blechnum serrulatum Acrostichum spp., Blechnum serrulatum 3A-3-16 Annona glabra, Persea borbonia Thelypteris interrupta, Blechnum serrulatum, Boehmeria cylindrical 3A-3-17 Ficus aurea, Sabal palmetto Boehmeria cylindrica, Saururus cernuus 3A-3-18 Sabal palmetto, Myrica cerifera, Persea borbonia Acrostichum sp., Blechnum serrulatum 3A-6-1 Ficus aurea Acrostichum spp., Osmunda regalis, Saururus cernuus 3A-6-2 3A-6-3 Ficus aurea, Myrica cerifera, Annona glabra, Salix caroliniana Annona glabra, Myrica cerifera, Persea borbonia, Salix caroliniana Blechnum serrulatum, Osmunda regalis Blechnum serrulatum, Cladium jamaicense 25

26 Table 5. cont. Tree Island ID 3A-6-4 3A-6-5 Dominant Canopy/Shrub Ficus aurea, Annona glabra, Myrica cerifera, Persea borbonia Ficus aurea, Annona glabra, Myrica cerifera, Salix caroliniana Dominant Herbaceous Blechnum serrulatum, Saururus cernuus, Osmunda regalis Blechnum serrulatum, Osmunda regalis, Acrostichum spp., Pontederia cordata 3A-6-6 3A-6-7 Ficus aurea, Myrica cerifera, Salix caroliniana Ficus aurea, Myrica cerifera, Annona glabra, Persea borbonia Blechnum serrulatum, Osmunda regalis, Acrostichum spp., Saururus cernuus Blechnum serrulatum, Osmunda regalis, Acrostichum spp. 3A-6-8 Ficus aurea Saururus cernuus, Blechnum serrulatum, Acrostichum spp., Thelypteris interrupta 3A-6-9 Ficus aurea, Myrica cerifera, Annona glabra Acrostichum spp., Thelypteris interrupta, Boehmeria cylindrica 3A-6-10 Annona glabra, Salix caroliniana, Myrica cerifera Blechnum serrulatum, Osmunda regalis, Acrostichum spp., Thelypteris interrupta 3A-6-11 Ficus aurea Stenotaphrum secundatum 3A-6-12 Salix caroliniana Blechnum serrulatum, Osmunda regalis, Pontederia cordata 3A-6-13 Schinus terebinthifolius, Ficus aurea, Salix caroliniana, Myrica cerifera Blechnum serrulatum, Acrostichum spp., Saururus cernuus 3A-8-1 Ficus aurea Saururus cernuus, Rivina humilis 26

27 Table 5. cont. Tree Island ID 3A-6-7 Dominant Canopy/Shrub Ficus aurea, Myrica cerifera, Annona glabra, Persea borbonia Dominant Herbaceous Blechnum serrulatum, Osmunda regalis, Acrostichum spp. 3A-6-8 Ficus aurea Saururus cernuus, Blechnum serrulatum, Acrostichum spp., Thelypteris interrupta 3A-6-9 Ficus aurea, Myrica cerifera, Annona glabra Acrostichum spp., Thelypteris interrupta, Boehmeria cylindrica 3A-6-10 Annona glabra, Salix caroliniana, Myrica cerifera Blechnum serrulatum, Osmunda regalis, Acrostichum spp., Thelypteris interrupta 3A-6-11 Ficus aurea Stenotaphrum secundatum 3A-6-12 Salix caroliniana Blechnum serrulatum, Osmunda regalis, Pontederia cordata 3A-6-13 Schinus terebinthifolius, Ficus aurea, Salix caroliniana, Myrica cerifera Blechnum serrulatum, Acrostichum spp., Saururus cernuus 3A-8-1 Ficus aurea Saururus cernuus, Rivina humilis 3A-8-2 3A-10-1 Annona glabra, Salix caroliniana, Myrica cerifera Annona glabra, Salix caroliniana, Myrica cerifera Acrostichum spp., Saururus cernuus Saururus cernuus, Blechnum serrulatum, Osmunda regalis, Pontederia cordata 3A-10-2 Ficus aurea Osmunda regalis, Boehmeria cylindrica, Acrostichum spp., Blechnum serrulatum, Andropogon glomeratus 3B-13-1 Ficus aurea, Annona glabra Rivinia humilis, Pluchea rosea 27

28 Table 5. cont. Tree Island ID Dominant Canopy/Shrub Dominant Herbaceous 3B-13-2 Annona glabra Pontederia cordata, Acrostichum spp. 3B-13-3 Schinus terebinthifolius no herbaceous layer on head 3B-15-1 Ficus aurea Stenotaphrum secundatum 3B B B-18-4 Schinus terebinthifolius, mostly dead Annona glabra, Salix caroliniana Persea borbonia, Myrica cerifera, Salix caroliniana Vitis spp., Rivinia humilis Acrostichum spp., Thelypteris interrupta, Pontederia cordata Blechnum serrulatum 3B-21-1 Ficus aurea Rivina humilis. 3B-21-2 Persea borbonia, Myrica cerifera, Annona glabra, Salix caroliniana Blechnum serrulatum 3B-21-3 Myrica cerifera, Persea borbonia, Salix caroliniana Blechnum serrulatum, Pontederia cordata 3B-21-4 Annona glabra Blechnum serrulatum, Acrostichum spp., Thelypteris interrupta 3B-21-5 Ficus aurea, Annona glabra Acrostichum spp. 3B-24-1 Persea borbonia, Salix caroliniana, Myrica cerifera Blechnum serrulatum, Acrostichum spp. 3B-24-3 Ficus aurea Acrostichum spp., Osmunda regalis, Saururus cernuus 3B-24-4 Persea borbonia, Myrica cerifera, Salix caroliniana Blechnum serrulatum, Osmunda regalis, Acrostichum spp., Pontederia cordata 3B-25-1 Bursera simaruba, Ficus aurea Rivina humilis, Sambucus canadensis 28

29 Table 5. cont. Tree Island ID Dominant Canopy/Shrub Dominant Herbaceous 3B-25-2 Ficus aurea Rivina humilis, Acrostichum spp. 3B B B B B-30-2 Annona glabra, Salix caroliniana Annona glabra, Myrica cerifera, Salix caroliniana Ficus aurea, Annona glabra, Myrica cerifera Schinus terebinthifolius, Ficus aurea Ficus aurea, Myrica cerifera, Chrysobalanus icaco Acrostichum spp., Pontederia cordata Blechnum serrulatum, Pontederia cordata, Acrostichum spp. Rivina humilis, Acrostichum spp. Rivinia humilis, Sesbania herbacea Thelypteris interrupta, Boehmeria cylindrica, Acrostichum spp. 3B-30-3 Ficus aurea, Annona glabra Acrostichum spp., Thelypteris interrupta, Boehmeria cylindrical 3B B B-31-2 Annona glabra, Salix caroliniana, Chrysobalanus icaco Annona glabra, Salix caroliniana Ficus aurea, Myrica cerifera, Persea borbonia, Chrysobalanus icaco Blechnum serrulatum, Acrostichum spp., Boehmeria cylindrical, Pontederia cordata Acrostichum spp., Thelypteris interrupta, Pontederia cordata Acrostichum spp. 29

30 Table 5. cont. Tree Island ID Dominant Canopy/Shrub Dominant Herbaceous 3A-6-14 Annona glabra, Salix caroliniana Saururus cernuus, Ribina humilis, Ludwigia peruviana, Ampelopsis arborea 3A A-6-15a 3A-6-15b Salix caroliniana dominated mixed with Annona glabra and Myrica cerifera Ficus aurea mixed with Myrica cerifera and Magnolia virginiana Ficus aurea mixed with Myrica cerifera and Magnolia virginiana Acrostichum spp., Blechnum serrulatum, Salix caroliniana seedlings Saururus cernuus, Blechnum serrulatum, Acrostichum spp., Ampelopsis arborea Saururus cernuus, Blechnum serrulatum, Boehmeria cylindrical, Thelypteris interrupta 3A-6-16 Salix caroliniana Acrostichum spp., Pontederia cordata 3A-10-3 Salix caroliniana, Myrica cerifera, Magnolia virginiana Osmunda regalis, Blechnum serrulatum 3A-6-17 Salix caroliniana Thelypteris interrupta, Pontederia cordata 3A A-8-3 3A-12-1 Ficus aurea mixed with Myrica cerifera, Magnolia virginiana, and Salix caroliniana Head cleared for camp, remaining trees were Taxodium distichum, Sabal palmetto, Syzgium cumini Myrica cerifera, Salix caroliniana, Ilex cassine Blechnum serrulatum, Acrostichum spp., Thelypteris interrupta Stenotaphrum secundatum Osmunda regalis, Blechnum serrulatum, Pontederia cordata, Cladium jamaicense 30

31 Table 5. cont. Tree Island ID 3A A A-11-2 Dominant Canopy/Shrub Salix caroliniana dominated mixed with Myrica cerifera Magnolia virginiana, Chrysobalanus icaco, Myrica cerifera, Salix caroliniana Eugenia axillaries mixed with Magnolia virginiana, Chrysobalanus icaco, Myrica cerifera Dominant Herbaceous Osmunda regalis, Blechnum serrulatum, Acrostichum spp., Typha latifolia Blechnum serrulatum, other species scarce Ampelopsis arborea 3A-11-3 Salix caroliniana, Annona glabra Pontederia cordata and Cladium jamaicense dominated some Blechnum serrulatum and Acrostichum spp. 3A A A A A-6-23 Ficus aurea mixed with Myrica cerifera, Magnolia virginiana, and Salix caroliniana Ficus aurea mixed with Myrica cerifera, Magnolia virginiana Myrica cerifera, Magnolia virginiana Ficus aurea, Salix caroliniana, Taxodium distichum, Annona glabra Ficus aurea, Salix caroliniana, Annona glabra Saururus cernuus, Blechnum serrulatum, Acrostichum spp., Thelypteris interrupta Thelypteris interrupta, Blechnum serrulatum, Pontederia cordata Blechnum serrulatum, Ampelopsis arborea, Aster carolinianus Saururus cernuus, Acrostichum spp., Thalia geniculata Boehmeria cylindrical, Ludwigia peruviana, Ampelopsis arborea, Vitis spp., Sambucus canadensis 31

32 Table 5. cont. Tree Island ID Dominant Canopy/Shrub Dominant Herbaceous 3A-6-24 Salix caroliniana, Annona glabra Cladium jamaicense, Osmunda regalis, Blechnum serrulatum, Pontederia cordata 3A-6-25 Annona glabra Blechnum serrulatum, Thelypteris interrupta, Acrostichum spp., Ampelopsis arborea 3A-14-1 Salix caroliniana, Annona glabra Saururus cernuus, Ludwigia peruviana, Acrostichum spp., Boehmeria cylindrical, Polygonum spp. 3A-6-26 Annona glabra mixed with Salix caroliniana, and Ficus aurea Ludwigia peruviana, Stenotaphrum secundatum 3A-6-27 Annona glabra, Ficus aurea Acrostichum spp., Blechnum serrulatum, Thelypteris interrupta, Saururus cernuus, Boehmeria cylindrical 3A-14-2 Salix caroliniana, Ficus aurea Thelypteris interrupta, Saururus cernuus, Boehmeria cylindrical, Ampelopsis arborea, Sambucus canadensis 3A-12-3 Salix caroliniana Osmunda regalis, Blechnum serrulatum, Acrostichum spp. 3A-6-28 Persia borbonia, Magnolia virginiana Blechnum serrulatum, Osmunda regalis, Acrostichum spp. 3A-6-29 Ficus aurea (tipped over) Saururus cernuus, Blechnum serrulatum, Acrostichum spp. 3A-6-30 Magnolia virginiana, 1 Ficus aurea, and 1 Sabal palmetto Blechnum serrulatum 32

33 Table 5. cont. Tree Island ID 3A-6-31 Dominant Canopy/Shrub Magnolia virginiana mixed with Myrica cerifera and Salix caroliniana Dominant Herbaceous Blechnum serrulatum, Acrostichum spp., Osmunda regalis, Thelypteris interrupta 3A-6-32 Magnolia virginiana Blechnum serrulatum, Thelypteris interrupta 3A-6-33 Persia borbonia, Magnolia virginiana, Annona glabra, Ficus aurea, Myrica cerifera and Salix caroliniana Blechnum serrulatum, Acrostichum spp., Osmunda regalis, Thelypteris interrupta 3A-6-34 Salix caroliniana Thelypteris interrupta, Boehmeria cylindrical, Cladium jamaicense, Pontederia cordata 3A-6-35 Annona glabra dominated mixed with Magnolia virginiana and Ficus aurea Blechnum serrulatum, Thelypteris interrupta 3A-6-36 Annona glabra Acrostichum spp., Osmunda regalis 3A-11-4 Magnolia virginiana, Salix caroliniana, Chrysobalanus icaco Sparse herb layer, few mixed ferns (Acrostichum spp., Osmunda regalis, Blechnum serrulatum, Thelypteris interrupta) 3A-11-5 Salix caroliniana Osmunda regalis, Thelypteris interrupta 3A-6-37 Acer rubrum Acer rubrum saplings, Boehmeria cylindrical 3A-6-38 Mix of Ficus aurea, Annona glabra, Persia borbonia, Myrica cerifera Blechnum serrulatum, Boehmeria cylindrical, Saururus cernuus, Amphicarpaea bracteata 33

34 Table 5. cont. Tree Island ID 3A-11-7 Dominant Canopy/Shrub Magnolia virginiana, Salix caroliniana, Chrysobalanus icaco Dominant Herbaceous Blechnum serrulatum, Thelypteris interrupta 3A-16-1 Salix caroliniana Blechnum serrulatum, Thelypteris interrupta, Pontederia cordata 3A A-19-1 Salix caroliniana, central Ficus aurea Chrysobalanus icaco, Salix caroliniana Boehmeria cylindrical, Saururus cernuus, Thelypteris interrupta, Ampelopsis arborea Amphicarpaea bracteata 3A-16-3 Salix caroliniana Osmunda regalis, Blechnum serrulatum 3A-14-3 Salix caroliniana, Annona glabra Osmunda regalis, Blechnum serrulatum 3A-14-4 Salix caroliniana Osmunda regalis, Blechnum serrulatum, Sambucus canadensis 3A Ficus aurea, and 2 Sabal palmetto Boehmeria cylindrical, Ludwigia peruviana, Thelypteris interrupta 3A A-22-1 Chrysobalanus icaco, Salix caroliniana 1 Annona glabra surrounded by Salix caroliniana Blechnum serrulatum, Amphicarpaea bracteata Thelypteris interrupta, Typha latifolia 3A-26-1 Chrysobalanus icaco Blechnum serrulatum 3A-26-2 Chrysobalanus icaco, Salix caroliniana Amphicarpaea bracteata 34

35 Table 5. cont. Tree Island ID Dominant Canopy/Shrub Dominant Herbaceous 3A-26-4 Chrysobalanus icaco Absent under Chrysobalanus icaco 3A-26-5 Salix caroliniana, Annona glabra Amphicarpaea bracteata, Ampelopsis arborea 3A-26-6 Chrysobalanus icaco Absent under Chrysobalanus icaco 3A-23-1 Bursera simaruba Smilax spp., Parthenocissus quinquefolia 3A A-9-1 Salix caroliniana, Chrysobalanus icaco, Bursera simaruba Magnolia virginiana, Myrica cerifera Seedlings/saplings from, Chrysobalanus icaco, Myrica cerifera, and Eugenia axillaris Thelypteris interrupta, Osmunda regalis 3A-9-2 Tipped Ficus aurea Thelypteris interrupta, Acrostichum spp., Amphicarpaea bracteata 3A-9-3 Ficus aurea surrounded by Salix caroliniana Thelypteris interrupta, Boehmeria cylindrical, Saururus cernuus, Ampelopsis arborea 3A-9-4 Salix caroliniana Osmunda regalis, Thelypteris interrupta, Cladium jamaicense, Pontederia cordata 3A-27-2 Salix caroliniana Sparse Blechnum serrulatum 35