A distributional and floristic study of known Hall's bulrush (Schoenoplectiella hallii, Cyperaceae) sites in Kentucky with implications for Tennessee.
Hall's Bulrush [Schoenplectiella hallii (A.Gray) Lye, Cyperaceae], formerly as Sehoenoplectus hallii (A.Gray) S.G.Smith, and Scirpus hallii A.Gray, is a small (< 35 cm tall) tufted annual that is globally rare and listed as threatened, endangered, or possibly extirpated in all states of known occurrence (McKenzie et al., 2007). In Kentucky it is endangered and critically imperiled (Kentucky State Nature Preserves Commission, 2012). Populations nearest those in Kentucky are in Missouri, Illinois, and Indiana (McKenzie et al., 2007). Typical habitats are freshwater shores, temporary ponds, wet places in cultivated fields, ditches, and sinkholes (Smith, 2002).
Studies relevant to the Kentucky sites include that of Baskin et al. (2003), who showed that germination requires a combination of flooding, ethylene, and light, and that of McKenzie et al. (2007), who presented a comprehensive review of the species. The latter report showed that the known distribution includes 84 sites scattered across 26 counties in 10 states. Also, the review outlined several research needs, including characterization of known sites of occurrence and determining the ecological associates, or species that consistently occur with S. hallii.
The purpose of this report is to: (1) characterize the six known sites in Kentucky; (2) list the flora of the sites; (3) identify the apparent ecological associates; and (4) note the possibilities of the species occurring in nearby Tennessee.
Materials and Methods
The study sites--All Kentucky sites presently known to harbor S. hallii are within the southern Pennyroyal Plain Subsection (PPS), Highland Rim Section, Interior Low Plateaus Province. The PPS landscape includes extensive level to rolling fields and is highly agricultural, mostly devoted to crops of corn, wheat, and soybeans. Shallow depressions with depths varying from < 1 to > 2 m and covering one to several ha are commonly embedded within the fields. When winter-to-spring rainfall is normal, most of the depressions are dry and tilled in spring. Conversely, when winter-to-spring rainfall is above normal, some depressions hold slowly receding water into late spring and often into summer. As waters recede, siltloam flats are exposed and a few species appear, showing a continuum of development from germlings at the water line to nearly mature plants at the periphery. Usually by middle to late summer the depressions have dried completely and most are then tilled in preparation for fall planting (wheat) or mowed/tilled for weed control, depending upon the agricultural practices being employed for that field.
The species was first found in Kentucky in 1983 (Chester, 1988). Since then, additional sites have been sought by driving area roadways in early spring and locating depressions with standing water, returning for surveys as water receded. More than 20 potential sites have been visited since 1983, but only five additional sites are known to harbor S. hallii. The sites are on private property in Christian County (Sites 1-5) and Logan County (Site 6). All are a few km north of the Tennessee border but the targeted species is not known from Tennessee. Data on locations and characteristics of the depressions at maximum flooding given in the following descriptions were taken from Google Earth (<http://www.google.com/earth/ download/ge>, accessed June 2012) and ground surveys. Site names are those of the author with the exception of Morgan Pond (Site 4); that name had been previously applied. Latitude/longitude immediately follows the site name.
Site 1, Highway 117 Pond (36.69729/87.45686). This site is centered 0.4 km west of U.S. HWY 41-A on KY HWY 117 just west of the Flying J Truck Stop. The junction of KY HWY 117 and U.S. HWY 41-A is 0.7 km south of Interstate-24. The depression covers ca 1.2 ha and is ca 2 m in depth. It borders HWY 117 on the south and is surrounded by cultivated land on the north and west. More than one-third of the depression was filled on the east side within the last 12 years for commercial development and the entire site is now posted for sale. This site provided the original Kentucky record for the species (Chester, 1988) and was the source of achenes used by Baskin et al. (2003) for germination studies. When present, S. hallii forms a nearly pure stand of thousands of plants (see Table 1 for usage history since 1983).
TABLE 1. Conditions at sites 1 and 3 during summers from 1983-2012.
1983. Flooded, S. hallii present
1984. Flooded, S. hallii present
1985. Flooded, S. hallii present
1986. Flooded, S. hallii present
1987. Flooded, S. present
1988. Flooded, S. hallii present
1989. Flooded, S. hallii present
1990. Dry, in tilth
1991. Flooded, S. hallii present
1992. Dry, in tilth
1993. Dry, in tilth
1994. Flooded, S. hallii present
1995. Dry, in tilth
1996. Dry, in tilth
1997. Flooded, S. hallii present
1998. Flooded, S. hallii present
1999. Dry, in tilth
2000. Dry, in tilth
2001. Dry, in tilth
2002. Flooded, S. hallii present
2003. Dry, in tilth
2004. Dry, in tilth
2005. Dry, in tilth
2006. Dry, in tilth
2007. Dry, in tilth
2008. Flooded, S. hallii present
2009. Flooded, S. hallii present
2010. Flooded, S. hallii present
2011. Flooded, S. hallii present
2012. Dry, in tilth
Site 2, Feltner Homesite Pond (36.69760/87.46563). This site is ca 8.3 km west of U.S HWY 41-A on KY HWY 117, then north within the same agricultural field as Site 1 for ca 0.6 km. This depression is shallow (< 1 m in depth) and covers ca 3 ha. When first observed in 2011, only a few plants of S. hallii (< 100) were seen: the depression was dry and cultivated in 2012.
Site 3, Bullard Field (36.69765/87.46570). This site is south of and adjacent to KY HWY 117, 1.1 km west of U.S. HWY 41-A. This elongated shallow depression (< 1 m in depth) is ca 50 m south of and extends parallel along KY HWY 117, covering ca 3 ha. Extensive stands of S. hallii may occur; see Table 1 for usage history since 1983.
Site 4, Morgan Pond (36.69359/87.47023). KY HWY 117, 1.5 km west of U.S. HWY 41-A, then 0.8 km south on Bullard Road; when Bullard Road forks, hold right onto a dirt road for 50 m. The depression is west of and almost adjacent to the dirt road. This is the largest in area of the six depressions, covering > 8 ha and up to 2 m in depth, but only a few S. hallii plants (< 25) were present in 2011 when the site was first observed; the site was dry and cultivated in 2012.
Site 5, Schott Pond (36.82402/87.434034). This site is 2.5 km south of Interstate 24 on U.S. HWY 41-A, then east on Walter Garrett Lane for 2.3 km; the site is south 0.6 km, accessible by walking along the edge of a field in cultivation. The shallow depression (< 1 m in depth) covers ca 4 ha. About 25 S. hallii plants were seen in 2011 and the site was dry and cultivated in 2012.
Site 6, James Young Road (JYR) (36.67108/87.03216). The site is 0.8 km west of the junction of JYR with Keysburg Road (KY 102), which is 1.6 km north of junction with KY 848. JYR is elevated for ca 0.5 m and bisects the site, which covers > 6 ha. However, flooding is shallow and the pond dries quickly. The site was first discovered in 2010 by Brainard Palmer-Ball, Kentucky State Nature Preserves Commission (retired). At that time, and in 2011, there were stands of several thousand S. hallii plants on both sides of the bisecting road (Chester and Palmer-Ball, 2011). The site was dry and cultivated in 2012.
Floristic studies--Sites 1 and 3 have been monitored since 1983 and floristic data taken in those years when Hall's Bulrush was present. The floristic data presented here were taken from all sites in August-September 2011. Each site was visited at least twice and a flora list compiled by walking over the depression as the water receded and again after the site had completely dried. Only dewatered areas that had been inundated for at least a month during the growing season were surveyed. Weedy peripheral areas adjacent to cultivation and that were not flooded, or with minimal flooding and without S. hallii, were not included in the surveys. Plants were identified and data on longevity (annual or perennial) and nativity were taken from Gleason and Cronquist (1991); nomenclature follows Chester et al. (2009) for all except two species, which were not included therein: Echinodorus tenelhis follows Gleason and Cronquist (1991), and Schoenoplectiella hallii follows Hayasaka (2012). Wetland indicator codes follow the US Army Corps of Engineers (2012) and USDA, NRCS (2012) with the following designations and definitions: OBL (obligate wetland), almost always a hydrophyte, rarely in uplands; FACW (facultative wetland), usually occur as a hydrophyte but occasionally found in uplands; FAC (facultative), commonly occur as either a hydrophyte or non-hydrophyte; FACU (facultative upland), occasionally a hydrophyte but usually in uplands. Ecological associates of S. hallii were designated based on the following criteria and included species that were: (1) present at all sites; (2) present during each year of the multiple years of observation for Sites 1 and 3; (3) widely disbursed throughout the dewatered zones; and (4) always present in relatively large numbers.
Results and Discussion
Thirty-six species within 19 families were found in 2011 on the dewatered flats of the six sites. All species found in Sites 1 and 3 in 2011 also had been observed in those sites for some or all of the previous years of observation since 1983. Twenty-five (69.5%) of the 36 species are native and 11(30.5%) introduced (Appendix). Twenty species were found in all sites, two in five, none in four, five in three, four in two, and five in one. Six taxa are perennial, but two of these, Ciperus strigosus and Bacopa rotundifolia, flowered during the year of germination and thus functioned as annuals. Sites with Rumex crispus and Typha latifolia were tilled or mowed before the species flowered. Two woody seedlings, Popu deltoides and Salix nigra, survived for part of one growing season before tillage.
Six of the 35 species observed with S. are considered to be ecological associates of that species. These obligate wetland annuals include Anunannia coccinea, Echinodorus tenellus, Eleocharis obtusa, Leucospora multifida, Lindernia dubia, and Rotala ramosior. The remaining 29 species were represented by a few plants and were never widely disbursed in a given site, although some were constant in occurrence (Appendix). Most of these 29 are characteristic species of agronomic fields and disturbed habitats, and account for the high incidence of non-native taxa (Appendix). All 35 are common taxa in the area with the exception of Echinodorus tenellus. This diminutive Burhead is known in Kentucky only from the six sites studied.
Implications for Tennessee--The Pennyroyal Plain Subsection, found mostly in Kentucky, extends into the northwestern Middle Tennessee counties of Stewart, Montgomery, Robertson, Cheatham, and Sumner. The same landscape as that found in Kentucky (flat to rolling, karst features) exists in at least parts of the noted counties. Searches of a few road-visible Tennessee depressions have not detected the presence of S. hallii. However, many depressions are not visible from roadsides, and enhanced methods like computerized aerial photography and low flyovers to locate remote depressions will likely lead to other possible sites of occurrence.
At least two factors may possibly facilitate spreading between depressions. Those with ponding are regularly visited by large numbers of shoreline, wading, and swimming birds. Also, when depressions are dry and tilled, the same agricultural equipment is often used over wide areas. Either or both of these factors may spread the abundantly produced, small achenes of S. hallii.
Based on the close proximity to Tennessee of the Kentucky sites, the presence of similar habitats, and the regular movement of avians and agricultural equipment between known (and unknown) sites, the likelihood of this globally rare species occurring in northern Middle Tennessee (and in other southern Kentucky sites) is great.
I thank the landowners who gave permission to visit their properties, and in one case, for not tilling a depression before plants reached maturity. Appreciation is extended to B. Palmer-Ball for discovering and calling to my attention Sites 5 and 6, and for helping with field work in 2011. Helpful comments were received from two anonymous reviewers.
Appendix. Floristic List, Alphabetical by Family.
An asterisk before a name indicates a non-native species. After the taxonomic authority the following information is given in parentheses: the sites in which the species occurred; an A for annual or P for perennial; and the wetland indicator code.
Echinodorus tenet/us (Mart.) Buch. (all sites; A; OBL).
* Amaranthus hybridus L. (all sites; A; no wetland code).
* Chenopodium album L. (Sites 1,2,3; A; FACU).
Ambrosia artemisiifolia L. (Sites 1.2,4; A; FACU).
Bidens aristosa (Michx.) Britton (all sites; A; FACW).
Eclipta prostrata L. (Sites 1,3,4; A; FACW).
* Xanthium strumarium L. (all sites; A; FAC).
* Heliotropium indicum L. (all sites; A; FAC).
Rorippa sessiflora Hitchc. (Sites 3,5; A; OBL).
* Ipomoea hederacea hey. (all sites; A; FACU). 2
Ipomoea lacunosa L. (all sites; A; FAC).
Cyperus strigosus L. (all sites; P; FACW).
Eleocharis obtusa (Willd.) Schultes (all sites; A; OBL).
Schoenoplectiella hallii (A.Gray) Lye (all sites; A; OBL)
Acalypha ostryifolia Riddell (Sites 1,2,4; A; no wetland code).
Euphorbia maculata L. (Sites 1,184.108.40.206; A; FACU).
Lindernia dubia (L.) Pennell (all sites; A; OBL).
Annnannia coccinea Rottb. (all sites; A; OBL).
Routala ramosior (L.) Koehne (all sites; A; OBL).
Sida spinosa L. (all sites; A; FACU).
Mollugo verticillata L. (all sites; A; FAC).
Bacopa rotundifolia (Michx.) Wettst. (Site 3; P; OBL).
Leucospora multifida (Michx.) Nutt. (all sites; A; OBL).
* Digitaria sanguinalis (L.) Scop. (all sites; A; FACU).
* Echinochloa crus-galli (L.) P. Beauv. (all sites; A; FACW).
Panicum dichotomiflorum Michx. (Site 6; A; FACW).
* Setaria faheri Herrm. (all sites; A; NA).
Urochloa platyphylla (Munro) Webster (Site 6; A; FAC).
Persicaria lapathifolium (L.) Gray (Site 4; A; FACU).
Persicaria pensylvanica (L.) M.Gomez (all sites; A; FACW).
* Rumex crispus L. (Sites 1,2; P; FAC).
* Portulaca oleracea L. (Site 3; A; FACU).
* Ranunculus sardous Crantz (Sites 1,2,3,4,6; A; FAC).
Populus deltoides Bartr. ex Marsh. (Sites 1,2; P; FAC).
Salix nigra Marsh. (Sites 1,2; P; OBL).
Typha latifolia L. (Sites 2,3.4; P: OBL).
Baskin, C. C., J. M. Baskin, E. W. Chester, and M. Smith. 2003. Ethylene as a possible cue for seed germination of Schoenopkctus hallii (Cyperaceae), a rare summer annual of occasionally flooded sites. American Journal of Botany, 90:620-627.
Chester, E. W. 1988. An unusual habitat type for three rare Kentucky plants. Transactions of the Kentucky Academy of Science, 49:59-60.
Chester, E. W., B. E. Wofford, D. Estes, and C. Bailey. 2009. A Fifth Checklist of Tennessee Vascular Plants. Sida, Botanical Misc. No. 31. Botanical Research Institute of Texas, Fort Worth, Texas.
Chester, E. W., and B. L. Palmer-Ball. 2011. A second county record for two Kentucky endangered species, Echinodorus tenellus (Alismataceae) and Schoenopkaus hallii (Cyperaceae). Phytoneuron, 43:1-4.
Gleason, H. A., and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. rd ed. New York Botanical Garden, New York.
Hayasaka, E. 2012. Delineation of Schoenoplectiella Lye (Cyperaceae), a genus newly segregated from Schoeno-plectus (Rehb.) Palla. Journal of Japanese Botany, 87:169-186.
Kentucky State Nature Preserves Commission. 2012. Kentucky Rare Plant Database. (http://eppcapp.ky.gov/nprareplants/index.aspx). Accessed December 2012.
McKenzie, P. M., S. G. Smith, and M. Smith. 2007. Status of Schoenoplectus hallii (Hall's Bulrush) (Cyperaceae) in the United States. Journal of the Botanical Research Institute of Texas, 1:457-481.
Smith, S. G. 2002. Schoenoplectus. Pp. 44-60 in Flora of North America north of Mexico (Flora of North America Editorial Committee). Vol. 23. Oxford University Press, New York.
USDA, NRCS. 2004--present. The PLANTS Database. National Plant Data Center, Baton Rouge, Louisiana. <http://plants.usda.gov>.
US Army Corps of Engineers. 2012. National Wetland Plant List-2012.
Manuscript received 22 January 2013; manuscript accepted 20 February 2013.
Edward W. Chester
Department of Biology, Austin Peay State University, Clarksville, TN 37044
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|Author:||Chester, Edward W.|
|Publication:||Journal of the Tennessee Academy of Science|
|Date:||May 1, 2013|
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