Pennyroyal Plain Depression Marsh
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Pennyroyal Plain Depression Marsh


Central Interior Highlands and Appalachian Sinkhole and Depression Pond (NatureServe 2015)


Northern Middle-Tennessee (northern Montgomery, Robertson, and Sumner counties).

Vegetation Description

Obligate and facultative wetland annuals and shrubs dominate this small patch community that ranges in height up to 2 m.  Distribution within the habitat is generally determined by water depth/permanence with smaller annuals growing on saturated exposed muds during drawdown periods.  Shrubs and emergent perennials grow in deeper regions that remain flooded for a longer period of time. 

Physical Characterization

This community occurs in the Western Pennyroyal Karst ecoregion in depressions created from the erosion and eventual collapse of the underlying limestone (Currens, 2002).  Elevation ranges from 146-198 m (479-649 ft.).  It occurs on flat to rolling landscapes (0%-2%) and on all aspects in topographic depressions.  Ponds range in size from 0.02 to 2.5 hectares (0.05- 6.18 acres).  The underlying geology is composed of Mississippian-aged limestone of the St. Louis and Ste. Genevieve formations (Sable & Denver 1990).  Soils are primarily silt-loams with pH ranging from 4.6-6.7.

Soil series involved:

Natural Processes

Continued erosion of the underlying limestone can enlarge existing marshes and create new habitats.  Seasonally fluctuating water levels is essential to the maintenance of these communities.  Historically, fire and megafauna were important to the maintenance of the surrounding grasslands and likely played a significant role in keeping depression marsh communities open as well.

Dominant Plants

Knowledge of the dominant species and overall community structure is lacking.  Plotwork is needed in order to better understand these areas.

Characteristic Plants

Amaranthus hybridus (slim amaranth), Bidens aristosa (bearded beggar ticks), Xanthium strumarium (rough cockleburr), Heliotropium indicum (Indian heliotrope), Ipomoea hederacea (ivyleaf morning glory), Ipomoea lacunosa (whitestar), Cyperus strigosus (strawcolored flat sedge), Eleocharis obtusa (blunt spike rush), Lindernia dubia (yellowseed false pimpernel), Ammannia coccinea (valley redstem), Rotala ramosior (lowland rotala), Sida spinosa (prickly fanpetals), Mollugo verticillata (green carpetweed), Leucospora multifida (narrowlead paleseed), Digitaria sanguinalis (hairy crab grass), Echinochloa crus-galli (barnyard grass), Setaria faberi (Japanese bristle grass), Persicaria pensylvanica (Pennsylvania smartweed)

Restricted Plants

Echinodorus tenellus (mudbabies) 1

Schoenoplectiella hallii (Hall’s bulrush) 1

Invasive Species


Community Variation and Subtypes

Variation in habitats is based on the permanence of water, diameter and depth of the pond, and vegetative structure (open water, marsh, or shrub swamp).  Additional research is needed to describe/characterize vegetative association of Pennyroyal Plain depression ponds.  The follow NVC (2015) associations are tentatively listed here because they are the most likely associations to occur in these ponds.

Carex comosa - Carex decomposita - Dulichium arundinaceum - Lycopus rubellus Herbaceous Vegetation (Nature Serve, 2015).

Scirpus cyperinus - Panicum rigidulum - Rhynchospora corniculata - (Dulichium arundinaceum) Herbaceous Vegetation (Nature Serve, 2015).

Scirpus cyperinus Seasonally Flooded Herbaceous Vegetation (Nature Serve, 2015).

Typha latifolia Southern Herbaceous Vegetation (Nature Serve, 2015).

Juncus effusus Seasonally Flooded Herbaceous Vegetation (Nature Serve, 2015).

Polygonum (hydropiperoides, punctatum) - Leersia spp. Herbaceous Vegetation (Nature Serve, 2015).

Polygonum amphibium - (Polygonum hydropiperoides) Seasonally Flooded Herbaceous Vegetation (Nature Serve, 2015).

Associated Natural Communities

Western Pennyroyal Karst Plain Hydric Sinkhole Swamp

Western Pennyroyal Karst Plain Hydric Sinkhole Shrub Swamp

Western Pennyroyal Karst Plain Wet Prairie

Similar Communities

Eastern Highland Rim Sinkhole Pond

Western Highland Rim Sinkhole Pond

Cumberland Plateau Depression Pond

Presettlement Distribution and Size

The current distribution of this community compared to its pre-settlement size is not known, however based on mapping of current sites in the search area and knowledge of the local geography, it is believed these habitats would have been found throughout the Western Pennyroyal Karst Plain in vast networks.  Heavy agriculture in the region has resulted in the erosion, filling, and, draining of depression marshes.  It has been suggested that there are far fewer depression marshes today than would have existed in pre-settlement times (Ellis & Chester, 1989).  As a result, interpool distances are greater today disrupting what would have been many networks of wetland systems throughout this landscape.  Based on historic writings and knowledge of experts regarding the pre-settlement landscape, these habitats would have been kept open as a result of the surrounding fire dependent grassland communities and through the effects of herbivory (Campbell, 2012).  Charles Wilkins Short described some of these areas in 1836 as he traveled through the “The Barrens” as “‘a smooth sheet of water, skirted with the blue and purple hues of the Pontederia [P. cordata] and Decodon [D. verticullatus], intermixed with the scarlet berries of the Prinos [Ilex verticillatus], whilst its surface was covered over with the large and floating leaves and splendid flowers of the Cyamus [Nelumbo lutea]; and then, in endless vistas, was stretched before the eye a waving sea of gigantic grasses’” (as cited in Campbell, 2012). 

Present Status

The majority of depression marshes exist today in agricultural fields.  Presently, most marshes are surrounded by a disturbed landscape or are left in a relatively unnatural state.

Representative Sites

Montgomery Co.:(36.60671, -87.16388)

Montgomery Co.:(36.55348, -87.17047)

Montgomery Co.:(36.58973, -87.14005)

Montgomery Co.:(36.62472, -87.17977)


These habitats are being destroyed and altered by dredging, filling, draining, runoff, livestock, construction, off-road vehicles, and generally most agricultural activity. 

Management Considerations

Floristic research is lacking for these communities and should be addressed.  Landowner education should be a priority for management considering almost all of these habitats are on private land.  Private landowners should be informed about the types of behaviors that are negatively impacting habitats and how they can help preserve or restore sites such as through prescribed burning.  Additionally, agencies should seek to obtain ownership of land to restore and/or maintain these communities. 

Future Research Needs

Very little data exists on the flora of depression marshes. This should be a focus in order to better manage conservation strategies.

Previous Studies

Edward W. Chester (2013) completed floristic inventories of six sites within the Western Pennyroyal Karst Plain ecoregion of Christian and Logan County, Kentucky that were known to also contain Schoenoplectiella hallii (Hall’s bulrush).  This may be one of the few floristic studies completed on these habitats thus far.


Baskin, J.M., Baskin, C.C., & Chester, E.W. 1994. The Big Barrens of Kentucky and Tennessee: Further Observations and Considerations. Castenea, 59(3), 226-254.

Baskin, J.M., Chester, E.W., & Baskin, C.C. 1997. Forest Vegetation of the Kentucky Karst Plain (Kentucky and Tennessee): Review and Synthesis. The Journal of the Torrey Botanical Society, 124(4), 322-335.

Campbell, J. 2012. The Big Barrens, and Other Native Grassland on Calcareous Lands Around the Shawnee Hills in Tennessee, Kentucky, Indiana, and Illinois. Retrieved from (Accessed: November 16, 2015).

Chester, E.W. 2011. Second County Records for Two Kentucky Endangered Species, Echninodorus tenellus (Alismataceae) and Schoenoplectus hallii (Cyperaceae).  Phytoneuron, 43, 1-4.

Chester, E.W. 2013. A Distributional and Floristic Study of Known Hall’s Bulrush (Schoenoplectus hallii, Cyperaceae) Sites in Kentucky with Implications for Tennessee. Journal of the Tennessee Academy of Science, 88(1), 35-38.

Currens, J.C. 2002. Kentucky is Karst Country! What you Should Know About Sinkholes and Springs.  Retrieved from (Accessed: November 16, 2015).

Ellis, W.H. & Chester, E.W. 1989. Upland Swamps of the Highland Rim of Tennessee. Journal of the Tennessee Academy of Science, 64(3), 97-101.

NatureServe. 2014. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Retrieved from (Accessed: October 26, 2015).

Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Web Soil Survey. Retrieved from (Accessed: 10/26/2015).

Checklist for this community (non-native species are indicated by an asterisk)


Echinodorus tenellus (Mart.) Buch


*Amaranthus hybridus L.

*Chenopodium albium L.


Ambrosia artemisiifolia L.

Bidens aristosa (Michx.) Britton

Eclitpa prostrata L.

*Xanthium strumarium L.


*Heliotropium indicum L.


Rorippa sessiflora Hitchc.


*Ipomoea hederacea Jacq.

Ipomoea lacunosa L.


Cyperus strigosus L.

Eleocharis obtusa (Willd.) Schultes

Schoenoplectus halii (A. Gray) S.G. Smith


Acalypha ostryifolia Ridell

Euphorbia maculata L.


Lindernia dubia  (L.) Pennell


Ammannia coccinea Rottb.

Rotala ramosior (L.) Koehne


Sida spinosa L.


Mollugo verticillata L.


Bacopa rotundifolia (Michx.) Wettst.

Leucospora multifida (Michx.) Nutt.


*Digitaria sanguinalis (L.) Scop.

*Echinochloa crus-galli (L.) P. Beauv.

Panicum dichotomiflorum Michx.

*Setaria faberi Herrm.

Urochloa platyphylla (Munro) Webster


Persicaria lapathifolium (L.) Gray

Persicaria pensylvanica  (L.) M. Gomez

*Rumex crispus L.


*Portulaca oleracea L.


*Ranunculus sardous Cratz


Populus deltoides Bartr. ex Marsh.

Salix nigra Marsh.


Typha latifolia L.

1 These species are currently only known from sites in Christian and Logan County, Kentucky and need to be searched for in Tennessee.

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