THE VASCULAR FLORA OF DALE COUNTY LAKE, ALABAMA.
A survey of the vascular flora of the area surrounding Dale County Lake was conducted from May 1998 through August 2000. The study site, located in the central section of Dale County, was comprised of 106 land ha and 37 water ha. Five major habitats, shoreline, mesic woods, xeric woods, wetland, and grassy area were found to occur at the study site. Collections were made once weekly from April through November and twice monthly from December through March. Similarity indices were determined by comparing this study with two other recent floristic studies from south Alabama. The 407 species representing 265 genera and 98 families found to occur at Dale County Lake are presented in an annotated checklist.
Publications dealing with the flora of Alabama are rare and are becoming increasingly outdated. Comprehensive treatments are limited to Mohr (1901) and Small (1933), while Harper (1943), Godfrey & Wooten (1979, 1981) and Godfrey (1988) concentrate on specific plant communities. In their work on the fauna and flora of Fort Rucker, Mount and Diamond (1992) collected 549 taxa of vascular plants. Diamond and Freeman (1993) reported 908 taxa of vascular plants from Conecuh County. Crouch and Golden (1997) listed 450 species of vascular plants from the area along the Tombigbee River in northeastern Choctaw County. Woods and Reiss (1998) reported 274 species and varieties from the area around Pike County Lake. In the most recent study, Rundell and Woods (2001) reported 507 species and varieties from the area around Ech Lake in the west-central section of Dale County, on the Fort Rucker Army Installation. Although these studies were comprehensive treatments of their collection area, additional records are needed to a dequately represent the diversity of plants found in south Alabama.
DESCRIPTION OF STUDY AREA
The Dale County Lake study area is located in the central part of Dale County, Alabama (31[degrees]45'N, 85[degrees]64'W) immediately outside and north-northeast of the city limits of Ozark. This places the study area entirely in the eastern division of the Southern Red Hills of the Coastal Plain Province. The soils are characteristic of those formed in the humid, subtropical climate of the southeastern section of the United States. They are derived from the sandy red clays of the Lafayette formation. The topsoil is paler and sandier, except where washed off on steep slopes (Harper 1943).
The climate in Dale County is considered subtropical-humid with long hot summers and short, mild winters. The annual growing season is approximately 250 days. Summer temperatures of above 30[degrees]C occur frequently and temperatures above 40[degrees]C are not uncommon. Cumulatively, the climate is considered very mild and therefore favors the growth of a wide variety of plant life (Brown 1999).
The Alabama Department of Conservation initiated the construction of Dale County Lake in 1956 and it was completed and opened to the public in 1958. The damming of Panther Creek, which serves as the primary inflow and outflow stream, formed the lake. Two smaller streams also serve as inflows for the lake. The study site comprised 106 ha of mostly forested, gently sloping land surrounding the 37 ha lake. The land and the lake are owned by the Alabama Department of Conservation and Natural Resources and managed by the City of Ozark Department of Parks and Recreation.
DESCRIPTION OF HABITATS
Five habitats were defined at Dale County Lake on the basis of topography, moisture content, and vegetation (Table 1). The shoreline habitat consisted of a narrow band of land along the edge of the lake. Found in this habitat were plants growing at the water edge, ranging from totally submersed to partially or completely immersed. The mesic woods habitat, which consisted of approximately 35 ha occurred on flat to gently rolling slopes that border the shoreline habitat. This area was composed of rich soils with an abundance of leaf litter. Soil moisture was abundant, and due to dense overhead vegetation light was limited at ground level. The xeric woods habitat, which consisted of approximately 50 ha consisted of well-drained sandy soils found at higher elevations on the study site. One exception was along the northeast side of the lake where the xeric habitat extended down to the shoreline. Loblolly Pines, which were planted more than twenty-five years ago, were the dominant trees in this area. Wetlands, whic h occurred in low-lying areas along Panther Creek and the two smaller inlet streams comprised approximately 12 ha of land. Most of this area only recently became wetlands due to the successful damming of the streams by beavers. In these wetlands, water was present at the soil surface throughout most of the year. In some areas, where the beavers were successful in damming the streams, water levels ranged from 0.5 to 1.0 meter deep throughout the year. Approximately 9 ha of grassland habitat were located around the central office, parking lot, boat-ramp, and land piers. Additional grassland habitat was found along the 5.6 km walking trail around the lake. Most of these grasslands were closely cut to benefit fishermen and those involved in other recreational activities.
The systematic collection of vascular plants of the Dale County Lake study area began in May of 1998 and continued through August of 2000. To obtain a more complete floristic list the five specific habitats were collected twice weekly from April through November and twice monthly from December through March. All seed plants, with the exception of some trees were collected with either flower or fruit. Seedless vascular plants were collected with sporangia. Voucher specimens were deposited in the herbarium of Troy State University (TROY).
Floristic similarity between Dale County Lake and two other similar studies in South Alabama was determined using Sorensens similarity coefficient (Mueller-Dobois and Ellenberg 1974) where:
IS = 2C/A+B x 100
IS = Index of Similarity
A = Total number of taxa at Ech Lake
B = Total number of taxa at comparison study site
C = Total number of taxa shared by A and B
This analysis provided a means of determining statistical similarities between this study site and other floristic studies conducted from south Alabama.
Sources used for identification and determination of non-native species were: Radford, Ahles and Bell (1968), Hitchcock (1971), Godfrey and Wooten (1979, 1981), Cronquist (1980), Godfrey (1988), Clewell (1985) and Isely (1990).
During the 28-month study period, 407 species representing 98 families and 265 genera were collected at Dale County Lake. The largest families were Asteraceae with 55 species, Poaceae with 34 and Fabaceae with 31. Carex and Smilax represented the largest genera with 7 species each. Cyperus, Eupatorium, and Quercus each had 6 species. Fifty-three introduced species were collected with at least one non-native species from each of the five habitats we characterized (Table 1). Murdannia keisak, an introduced species from Asia, was collected during this study. This was the second reported location of this species from Dale County and only the third report from Alabama (Rundell and Diamond 1999).
The two floristic investigations used to determine the index of similarity were chosen because they share certain features with the present study, such as size of the study areas, physiographic factors, and climate. In the study "The vascular flora of Ech Lake, Alabama" (Rundell and Woods 2001), an area of 162 ha located in the west-central section of Dale County, a total of 507 species, representing 289 genera and 102 families were reported. Woods and Reiss (1998) reported 274 taxa representing 198 genera and 86 families in their study of Pike County Lake (220 ha). A total of 180 species collected at the Dale County Lake study area were also found to occur at Pike County Lake. This gave an index of similarity of 52.86 between these two studies. Dale County Lake and Ech Lake had 268 species in common and an index of similarity of 58.64. An index of similarity of 48.39, with 189 species in common, was calculated from the comparison of Pike County Lake and Ech Lake (Table 2).
After 28 months of intensive collecting, this list of 407 taxa must include nearly all species occurring at the Dale County Lake study area. Since much of the study site is a managed disturbed area, the likelihood of documenting all species of vascular plants growing at Dale County Lake is improbable. For example, sportsmen and others involved in various forms of recreation constantly alter the habitats and are likely responsible for the eradication of some species and the introduction of others. Additionally, the successfulness of the beavers in damming the creeks has caused a rapid change in wetland habitats.
Fifty-three (13.0%) of the species on our checklist are non-native. Twenty-one (39.6%) of these were collected from the grassland habitat, the most disturbed habitat at the study area. These 21 species represent 32.3% of the total (65) collected from this habitat. In the remaining four habitats (shoreline, mesic woods, xeric woods and wetlands), which are the least disturbed, only 32(9.4%) of the species are non-native (Table 1).
According to Vitousek (1988), non-native plants constitute 6-27% of the flora from the national parks in the United States. Most of these non-native species are confined to such sites as agricultural land, roadsides, and recreation areas. This is likely true for our study area as well, since 39.6% of the non-native flora occurred in the most disturbed habitat. Basinger et al. (1997) reported the percentage of introduced species from intensively managed and non-intensively managed sites in Illinois, Missouri, and Tennessee ranged from 17.6% to 21.3% and 2.7% to 15.7%, respectively. The 13.0% of non-native species collected during this survey would suggest that the study area is non-intensively managed with a small number of introduced species. Although the study area is heavily used in various forms of recreation, the land is not managed to create wildlife habitat. Additionally, management techniques such as burning and selective logging are not practiced. With the exception of the grassland habitat, very few management practices occur. Most of the grassland habitat is located around the central office, parking lot, boat-ramp, land piers, and along the 5.6 km walking trail around the lake. Although the walking trail passes through the four least disturbed habitats, very little vegetation damage has occurred because most people remain on the trail. Since little disturbance has occurred in these habitats, the opportunity for non-native species to be introduced and become established has been minor.
All three of the study sites selected to determine index of similarity are in the Eastern Red Hills Region of the Coastal Plain Providence of southeast Alabama. According to Barbour et al. (1987), two sites with an index of similarity greater than 50 represent the same community types. Based on this criterion, Ech Lake and Dale County Lake have the most similar community types (IS = 58.64). In part, this could be due the fact that these two sites are closely located to one another. Dale County Lake is 16 km northeast of Ech Lake. The Dale County Lake site is 47 km southeast of Pike County Lake and these two sites have an index of similarity of 52.86. Both of these sites consist primarily of moderately drained soils, which form a mesic habitat. The index of similarity between the Pike County Lake site, located 49 km north of Ech Lake, is 48.39. Several factors, including habitat diversity and number of species collected, likely contribute to these three sites not having higher index similarities. For example, cypress swamps and ravines, which are present at both the Dale County and Pike County sites, do not occur at Ech Lake. Additionally, most soils around Ech Lake are excessively to moderately drained resulting in extremely xeric conditions. Only 274 taxa were collected during the Pike County study. This was attributed to Hurricane Opal, which occurred during the course of the study. Extensive vegetation damage was done by the hurricane and by subsequent logging crews, which were brought in to clear potentially hazardous debris. Several normally abundant species could not be found due to the stress on the ecosystem caused by both the hurricane and the logging and burning operation conducted afterwards (Woods and Reiss 1998).
It is hoped that this survey of the vascular flora of the Dale County Lake study area will provide a basis of comparison for future floristic studies at other county lakes and similar areas in Alabama. Also, the information contained in this list could be used to inform the public of the uniqueness of the plants in the area.
The authors would like to thank The Alabama Department of Conservation and the Ozark Department of Parks and Recreation for granting permission to conduct this study at Dale County Lake. Also, we are greatful to Hannelore Rundell, Tiffany Pennington and Brian Martin for their help during this project. The second author would like to thank the College of Arts and Sciences at Troy State University for awarding him a Chancellor's Fellowship. Support for this project was provided by The Alabama Department of Public Health ALERT Grant.
Barbour, M.G., J.H. Burke, and W.D. Pitts. 1987. Terrestrial plant ecology, 2nd ed. The Benjamin/Cummings Company, Menlo Park, California.
Basinger, M.A., J.S. Huston, R.J. Gates, and P.A. Robertson. 1997. Vascular Flora of Horseshoe Lake Conservation Area, Alexander County, Illinois. Castanea 62(2): 82-99.
Brown, M. 1999. Weather data for the years 1997 and 1998. Personal communication with the National Weather Service.
Clewell, A.F. 1985. Guide to the vascular plants of the Florida Panhandle. Florida State University Press, Tallahassee.
Cronquist, A. 1980. Vascular flora of the southeastern United States. Volume I. Asteraceae. The University of North Carolina Press, Chapel Hill.
Crouch, V.E. and M.S. Golden. 1997. Floristics of a bottomland forest and adjacent uplands near the Tombigbee River, Choctaw County, Alabama. Castanea 62(4): 219-238.
Diamond, A.R. and J.D. Freeman. 1993. A checklist of the vascular flora of Conecuh County, Alabama. Sida 15(4):623-638.
Godfrey, R.K. 1988. Trees, shrubs and woody vines of Northeastern Florida and adjacent Georgia and Alabama. University of Georgia Press, Athens.
Godfrey, R.K. and J.W. Wooten. 1979. Aquatic and wetland plants of the southeastern United States. Monocotyledons. University of Georgia Press, Athens.
Godfrey, R.K. and J.W. Wooten. 1981. Aquatic and wetland plants of the southeastern United States. Dicotyledons. University of Georgia Press, Athens.
Harper, R.M. 1943. Forests of Alabama. Alabama Geol. Surv. Monograph 10:1-230.
Hitchock, A.S. 1971. Manual of the grasses of the United States. Volumes I & II. General Publishing Company, Ltd., Tornonto.
Isely, A. 1990. Vascular flora of the southeastern United States. Volume III, Part 2. Leguminosae (Fabaceae). The University of North Carolina Press, Chapel Hill.
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Mohr, C. 1901. Plant life of Alabama. Government Printing Office. Washington D.C.
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Mueller-Dombois, D. and H. Ellenbery. 1974. Aims and methods of vegetation ecology. Wiley, New York.
Radford, A.E., H.E. Ahles and C.R. Bell. 1968. Manual of the vascular flora of the Carolinas. The University of North Carolina Press, Chapel Hill.
Rundell, H. and A.R. Diamond. 1999. Noteworthly collections from Alabama. Castanea 64(4):355-356.
Rundell, H. and M. Woods. 2001. The vascular flora of Ech Lake, Alabama. Castanea 66(4):in press.
Small, J.K. 1933. Manual of the southeastern flora. The University of North Carolina Press, Chapel Hill.
Vitousek, P.M. 1988. Diversity and biological invasions of oceanic islands. P. 181-189 In: Wilson, E.O. and F.M. Peters (eds.). Biodiversity, Chapter 13, National Academic Press, Washington, D.C.
Woods, M. and J. Reiss. 1998. The vascular flora of Pike County Lake, Alabama. J. Alabama Acad. Sci. 69(3):300-314.
Table 1. Habitats and the number of species collected at each Habitats Number of Species Collected Number of Non-Native Species Shoreline 27 1 Mesic Woods 197 23 Xeric Woods 52 3 Wetland 58 5 Grassland 65 21 Table 2. Indicies of similarity between Dale County Lake and two study sites. Study Ha # of taxa Index of similarity (%) Ech Lake 162 507 58.64 with Dale County Lake 48.39 with Pike County Lake Pike County Lake 220 274 48.39 with Ech Lake 52.86 with Dale County Lake Dale County Lake 142 407 100
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|Author:||Woods, Michael; Prazinko, Brian; Diamond Jr., Alvin R.|
|Publication:||Journal of the Alabama Academy of Science|
|Article Type:||Statistical Data Included|
|Date:||Jan 1, 2001|
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