A calcareous glade is a type of ecological community that is found in the central Eastern United States. Calcareous glades occur where bedrock such as limestone occurs near or at the surface, and have very shallow and little soil development. Due to the shallow soil and the extreme conditions created by it, trees are often unable to grow in the glades. This creates a habitat that is usually sunny, dry, and hot. Calcareous glade vegetation is more similar to that of a desert habitat than a grassland, being dominated by small spring annuals with occasional geophytic or succulent perennials.
The usage of the words "glades" and "barrens" to describe dry, rocky communities in the United States is not uniform, and the terms are often used interchangeably. [1] Calcareous glade communities can intergrade with dry rocky prairies, particularly in sloping habitats. Due to their unsuitability for agriculture, glade communities have survived to the present day at a higher rate than deeper-soil prairie communities. [1]
The Interior Low Plateau is a region in the Upper South that is known for its calcareous glade communities. This region is centered in Tennessee and Kentucky, and extends into northern Alabama, and southern Illinois, southern Indiana, and southern Ohio. These glades are best developed in the area of the Central Basin (or Nashville Basin) in Tennessee, where they are geographically widespread and harbor high levels of endemism. Outside of the Central Basin, calcareous glades are found in lower numbers throughout the Interior Low Plateau, and species endemism is greatly reduced. Glades in the Interior Low Plateaus are characterized by species such as one-flower gladecress ( Leavenworthia uniflora ), limestone skullcap ( Scutellaria parvula ), widow's-cross stonecrop ( Sedum pulchellum ), poverty dropseed ( Sporobolus vaginiflorus ) and glade violet ( Viola egglestonii ). [2]
The limestone glades of the Central Basin in Tennessee are often called "cedar glades". The name comes from the abundance of eastern red cedar ( Juniperus virginiana ) that occurs on the margins of the glades or in cracks in the bedrock where the roots can gain a foothold.
Many of the characteristic plants that grow in the limestone glades of the Central Basin are endemics that occur nowhere else, or disjunct populations of plants that are widespread in the prairies of the central U.S. [3] Some species with highly restricted ranges that occur in the glades of the Central Basin include the Tennessee coneflower ( Echinacea tennesseensis ), Pyne's ground plum ( Astragalus bibullatus ), leafy prairie clover ( Dalea foliosa ), Tennessee milkvetch ( Astragalus tennesseensis ), Nashville breadroot ( Pediomelum subacaule ), and limestone fameflower ( Phemeranthus calcaricus ).
These glades can be saturated with water in the winter and spring, leading to "xerohydric" (dry/wet alternating) conditions. [4]
The central basin (or Nashville Basin) of Tennessee is one of the largest areas containing limestone glades. Because of the rapid growth of metropolitan Nashville and the surrounding cities of Murfreesboro and Lebanon, many of the limestone glades have been destroyed by development. The State of Tennessee and the Nature Conservancy have established a number of parks and preserves to protect important plant populations. Cedars of Lebanon State Park in Wilson County and Long Hunter State Park in Davidson County both protect substantial limestone glade ecosystems.
The limestone slope glades of Kentucky are a globally vulnerable habitat consisting of limestone glades found on hillsides, which are wet in the spring but become very dry in the rest of the year. This provides habitat for unique species such as necklace glade cress, Butler's quillwort, and Crawe's sedge. [5]
This is a list of calcareous glade-adapted plant species considered endemic to the Interior Low Plateau region. Some are found in only a single county of a single state. [6]
Calcareous glades are well developed in the Ozark Mountains. In Missouri, the majority of these glades are found on dolomitic limestones, with less than 1% formed from calcitic limestone. [1] Species indicative of Ozarkian calcareous glade communities include Cheilanthes feei (slender lip fern), Echinacea simulata (pale purple coneflower), Heliotropium tenellum (pasture heliotrope), Isoetes butleri (limestone quillwort), Oenothera macrocarpa (Missouri evening primrose), and Ophioglossum engelmannii (limestone adder's-tongue). [1] In Missouri, Physaria filiformis (Missouri bladderpod) is a species restricted to calcitic limestone glades. [1]
The Ridge-and-Valley Appalachians, which extend north from Pennsylvania south to Alabama, have significant calcareous glade communities. [7] These glades often have dolomitic soils, resulting in a high magnesium content (in contrast to the glades of the Nashville Basin). In Virginia, these glades provide habitat for rare magnesiophiles such as Addison's leatherflower ( Clematis addisonii ), tall larkspur ( Delphinium exaltatum ), smooth coneflower ( Echinacea laevigata ), and glade wild quinine ( Parthenium auriculatum ). [8]
At the southern end of the Ridge and Valley in Alabama in Bibb County, species endemism of glade communities peaks. This area, known as a Ketona Dolomite Outcrops, was first recognized as ecologically significant in 1992. Since its discovery, eight new plant taxa to science have been described from this region, in addition to the 60 species of conservation concern found in or around this community. [9] Endemic species of this area include Castilleja kraliana , Dalea cahaba , Liatris oligocephala , Lithospermum decipiens , and Spigelia alabamensis .
Echinacea is a genus of herbaceous flowering plants in the daisy family. It has ten species, which are commonly called coneflowers. They are found only in eastern and central North America, where they grow in moist to dry prairies and open wooded areas. They have large, showy heads of composite flowers, blooming in summer. The generic name is derived from the Greek word ἐχῖνος, meaning "sea urchin", due to the spiny central disk. These flowering plants and their parts have different uses. Some species are cultivated in gardens for their showy flowers. Two of the species, E. tennesseensis and E. laevigata, are listed in the United States as endangered species.
The Nashville Basin, also known as the Central Basin, is a term often used to describe the area surrounding Murfreesboro, Tennessee, in which Nashville is located. The Central Basin was caused by an uplifting which produced a dome known as the Nashville Dome. The Nashville Dome is evidenced by the underlying rock strata that all dip downwards away from Nashville. The uplifting of the Nashville Dome fractured overlying strata, making it more easily eroded and thus the "dome" resulted in a "basin". Uplifted strata in the center of a geological dome have higher potential erosive energy than the surrounding strata, because they are physically higher. Erosion thus acts on the uplifted area at a greater rate than on the surrounding flat-lying area, creating a low area, i.e. a basin. This area is more correctly referred to as the "Central Dome" of Tennessee.
Echinacea tennesseensis, also known as the Tennessee coneflower or Tennessee purple coneflower, is a flowering plant in the family Asteraceae, endemic to the cedar glades of the central portion of the U.S. state of Tennessee.
Astragalus bibullatus, the limestone glade milkvetch or Pyne's ground plum, is an endangered species of flowering plant that is endemic to the cedar glades of the central basin of Tennessee in the United States. It is found in only eight populations located within a few kilometers of each other in Rutherford County, Tennessee.
Eriogonum longifolium var. harperi, also known as Harper's buckwheat or Harper's umbrella plant, is a dicot of the family Polygonaceae, found in areas of nutrient-poor shale soils in Alabama, Kentucky and Tennessee. It lives inconspicuously in an immature vegetative stage for four or more years before developing a flowering stalk, then flowers and dies. It is listed as an endangered species by the state of Tennessee. It has eleven small populations in Alabama and five in Tennessee but its survival in Kentucky is uncertain. According to a leading expert, Professor James L. Reveal of the University of Maryland, its Kentucky population has been reportedly extirpated. Its 2006 Alabama Natural Heritage Program ranking was G4T2S1, demonstrating an opinion that it was "critically imperiled" in that state.
Echinacea simulata, commonly called wavy leaf purple coneflower, glade coneflower, or prairie purple coneflower, is a species of perennial flowering plant in the family Asteraceae. It is native to the east-central states of the United States. Its natural habitat is dry, calcareous, open areas such as barrens and woodlands.
Echinacea paradoxa, the yellow coneflower, Bush's purple coneflower, or Ozark coneflower, is a North American species of flowering plant in the family Asteraceae. It is native to southern Missouri, Arkansas, and south-central Oklahoma, It is listed as threatened in Arkansas.
Elsie Quarterman was a prominent plant ecologist. She was a Professor Emerita at Vanderbilt University.
Cedars of Lebanon State Park is a state park in Wilson County, Tennessee, in the southeastern United States. It consists of 900 acres (364 ha) situated amidst the 9,420-acre (3,810 ha) Cedars of Lebanon State Forest. The park and forest are approximately 10 miles (16 km) south of Lebanon, Tennessee.
Dalea foliosa, commonly called leafy prairie clover, is a species of flowering plant in the legume family (Fabaceae). It is an endangered species in the United States, where it occurs in three states: Illinois, Tennessee, and Alabama.
Paysonia perforata, known by the common name Spring Creek bladderpod, is a rare species of flowering plant in the mustard family. It is endemic to Tennessee in the United States, where it is known only from Wilson County. This very rare plant is threatened by the loss and degradation of its habitat. It is federally listed as an endangered species.
Astragalus tennesseensis is a species of flowering plant in the legume family known by the common name Tennessee milkvetch. It is native to the United States, where it is known from Illinois, Indiana, Tennessee and Alabama. Most of the occurrences are in Tennessee.
The Interior Low Plateaus are a physiographic region in eastern United States. It consists of a diverse landscape that extends from north Alabama across central Tennessee and Kentucky into southern Illinois, Indiana, and Ohio. Its natural communities are a matrix of temperate forests, woodlands, and prairies.
Pediomelum subacaule is a species of flowering plant in the legume family known by the common names Nashville breadroot and whiterim scurfpea. It is native to a small area of Eastern North America, only being found in limestone cedar glades of the Interior Low Plateau and Ridge and Valley ecoregions of Alabama, Georgia, and Tennessee.
Leavenworthia crassa is a species of flowering plant in the mustard family, Brassicaceae, known commonly as the fleshy-fruit gladecress. It is endemic to Alabama in the United States, where it occurs in only two counties. It is "likely one of the most imperiled plant species in the Southeast," and the United States Fish and Wildlife Service issued a final rule listing it as an endangered species in 2014.
Dalea gattingeri, commonly called purpletassles or Gattinger prairie clover, is a species of flowering plant in the legume family. It is native to the Southeastern United States, where it is restricted to limestone cedar glades of Tennessee, Alabama, Georgia, Missouri, and Arkansas. Its populations are widely dispersed and geographically small, with most populations being found in the Nashville Basin.
Solidago gattingeri, common name Gattinger's goldenrod, is a species of plant that is a goldenrod. It is native only to the Ozark Mountains of Arkansas and Missouri and to the Nashville Basin of Tennessee. Its preferred habitat is cedar glades, cedar barrens, and limestone outcrops. It is adapted to dry habitats.
Lithospermum molle, the softhair marbleseed, is a species of flowering plant in the forget-me-not family. This species is a narrow endemic, native primarily to the Nashville Basin of Tennessee, where it is found in limestone prairies near cedar glades. There are disjunct populations in similar habitats in the Ozark Mountains of Missouri, in northwest Alabama, in Logan and Warren County, Kentucky as well as other small areas of Tennessee. Outside of Tennessee, it is very rare and perhaps no longer exists in Alabama and Kentucky due to habitat destruction. Because of its highly restricted geographic range, this species is considered vulnerable.
Leavenworthia torulosa, the necklace gladecress, is a species of plant in the mustard family. It is native to the eastern United States where it is only found near limestone cedar glades of Alabama, Georgia, Kentucky, and Tennessee. It is considered rare in all states it is found except Tennessee, where it is common in the Nashville Basin due to the abundance of available habitat.
Couchville Cedar Glade State Natural Area is a Class II Natural-Scientific state natural area located in Davidson and Wilson counties Tennessee. Its western boundary is contiguous with the eastern boundary of Long Hunter State Park. The park's name reflects its location near the now extinct inundated community of Couchville, Tennessee.