typical igneous cliff habitat would show sparsely vegetated granite and rhyolite stone ledges and irregularly jaunting vertical slopes covered with gnarled black jack oaks and lichens. Bluffs of Iron, Shannon, Reynolds and Wayne counties showcase this type of cliff community the best.
Big Creek in southeastern Missouri has, over the centuries, cut its way through Mudlick Mountain, creating giant sheer bluffs and spectacular shut-ins. Here, serviceberry trees, covered with their snow-white blossoms, seem to chant “spring is here” well before other trees break open their tiny buds.
With heights of 100 feet or more, igneous cliffs are exposed to the elements. Storms, prevailing winds, sunlight and extreme temperature fluctuations during both winter and summer take their toll upon any vegetation attempting to live upon the volcanic stone.
Plants that root into the rock strata of the St. Francois Mountains, Johnson’s Shut-Ins and Royal Gorge Natural Area are suited to varying microhabitats. Moist crevices and ledges support liverworts, ferns and algae, while drier sites are composed of glade plants such as tickseed coreopsis, aromatic aster and wild hyacinth.
Visitors touring the Wildcat Glades area of southwest Missouri may view small, restricted chert cliffs. The banks of Shoal Creek showcase dry, sparsely vegetated formations with heights much lower than bluff areas composed of igneous, limestone or dolomite.
During May and June blossoms of columbines grace the moist ledges and vertical cracks. Plants with adaptations more suited to dry, desert-like conditions include eastern prickly pear cactus, armed with its sharp spines and waxy-textured outer covering of succulent stems. Wildcat Glade represents a rare community found only in small-acre patches worldwide.
In contrast to the dry desert nature of the chert at Wildcat, many valleys of the Missouri River in Callaway County are home to moist chert cliffs and rocky terraces composed of lumpy formations known as Graydon Conglomerate. Growing upon more northern and eastern exposures of cliffs within the Earthquake Hollow Conservation Area are populations of ferns and other herbaceous plants that provide a lush habitat for insects, reptiles and amphibians.
Designated a Natural Area in 1986, Pickle Springs entices hikers and campers throughout the year with its dry and moist sandstone formations adorned with short-leaf pine and mountain azalea. Plants found growing in this unique community also include hay-scented ferns and blue ground cedar. Adjacent glades, forests and savannas provide habitat for a variety of plant and animal life, which depend upon sandstone communities for their survival.
Drier sandstone cliff communities commonly display stunted oak and hickories as well as grape vines and sedges. Rocky Hollow Natural Area in Monroe County and Buzzards Bluff in St. Clair County provide good examples of exposed dry sandstone ledges.
Ferns such as mountain spleenwort and common polypody are well adapted to sand-enriched bluffs. Harebell and northern white violet are considered plant relicts and also find refuge upon select moist ledges and cliff overhangs.
Totally restricted to sandstone sites, French’s shooting star flowers for a short time in early to mid-spring. It is a rare treat to come upon this compact and lovely delight with its ruffled, green leaves and pure white flowers. French’s shooting star is listed as a species of conservation concern in Missouri. On a global scale, it is listed as vulnerable.
Current Threats to Cliff Communities
Cliff habitats and their native species are threatened by a host of disturbances. Some of the most damaging are Japanese honeysuckle and kudzu vines and other exotic species, as well as invasion by woody vegetation such as eastern red cedar, which can be aggressive on open cliff habitats.
Domesticated animals can devastate cliff communities, especially those with moist microhabitats. They provide attractive lush vegetation that is prone to overgrazing.
Activities such as rock climbing or rappelling can damage and destroy entire delicate colonies of mosses, ferns and lichens that took many years to become established. Once a microhabitat is disturbed, its composition may change, allowing invaders to get a stronghold and cause even further destruction to the native ecosystem.
When planning your next outdoor adventure, grab a paddle and a pair of binoculars. Then prepare to experience a few of nature’s unique cliff sites firsthand. By observing our natural rock-face communities by canoe or established trails, we can help ensure that our grandchildren and their grandchildren will also be able to experience some cliff hangers of their own along our scenic waterways.