Algific talus slope
Encyclopedia
Algific talus slopes comprise a very rare, fragile ecosystem
and habitat
stated to exist only in the Driftless Area of Minnesota
, Wisconsin
, Illinois
, and especially, Iowa
. Others suggest, however, that close comparison between similar sites worldwide may enlarge the distribution, or that the term may become restricted to the flora and fauna characteristic of these zones within the Driftless Area.
" refers to a collection of talus or broken rock which rests near the surface it detached from. A related term is maderate cliff, which is an algific slope lacking talus. They were first described in the early 1980s. These ecosystems can only exist in regions displaying karst topography
.
Algific talus slopes are found mainly on north-facing slopes of ridges and canyons and are characterized by crumbly, heavily fissured, and porous exposed bedrock, with an overburden of talus remaining in situ from where it detached from its underlying bedrock; it may also display scree
, which is talus finding its narrowest angle of repose
down-canyon. This is a "unique system involving ridgetop sinkhole
s and subterranean ice cave
s; this system also supports Maderate Cliffs." The valleys in which they occur tend to be very steep, and often have dense forest cover.
This causes a cooler, more moist summer environment than that which may occur a relatively short distance away. The result is a rather boreal ecosystem
more associated with that found to the north at the Canadian border. It can also host relict populations not found elsewhere locally. "The vegetative community on algific talus slopes is different than the surrounding forest and typically contains ferns, mosses, liverwort
s, evergreen species such as Canada yew and balsam fir
, birch
, basswood, and sugar maple
, and boreal disjunct herbs and ferns."
The great majority of the protected sites are closed to the general public, and in fact, are notably undocumented on the net, in order to keep them out of the eye of those who would vandalize them. One place that can be visited, however, is Bixby State Preserve
, in northwestern Clayton County, Iowa
.
in 1989 to protect this species, as well as threatened and some relict species. Much of this refuge was carved out of pre-existing protected areas, most notably the Upper Mississippi River National Wildlife and Fish Refuge
. The Northern monkshood is a threatened wildflower in the buttercup family (Ranunculaceae
) occurring in the Driftless Area as well as in New York State and receives similar protection.
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
and habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
stated to exist only in the Driftless Area of Minnesota
Minnesota
Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
, Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...
, Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
, and especially, Iowa
Iowa
Iowa is a state located in the Midwestern United States, an area often referred to as the "American Heartland". It derives its name from the Ioway people, one of the many American Indian tribes that occupied the state at the time of European exploration. Iowa was a part of the French colony of New...
. Others suggest, however, that close comparison between similar sites worldwide may enlarge the distribution, or that the term may become restricted to the flora and fauna characteristic of these zones within the Driftless Area.
Description
Algific means "cold producing" while "talus slopeScree
Scree, also called talus, is a term given to an accumulation of broken rock fragments at the base of crags, mountain cliffs, or valley shoulders. Landforms associated with these materials are sometimes called scree slopes or talus piles...
" refers to a collection of talus or broken rock which rests near the surface it detached from. A related term is maderate cliff, which is an algific slope lacking talus. They were first described in the early 1980s. These ecosystems can only exist in regions displaying karst topography
Karst topography
Karst topography is a geologic formation shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite, but has also been documented for weathering resistant rocks like quartzite given the right conditions.Due to subterranean drainage, there...
.
Algific talus slopes are found mainly on north-facing slopes of ridges and canyons and are characterized by crumbly, heavily fissured, and porous exposed bedrock, with an overburden of talus remaining in situ from where it detached from its underlying bedrock; it may also display scree
Scree
Scree, also called talus, is a term given to an accumulation of broken rock fragments at the base of crags, mountain cliffs, or valley shoulders. Landforms associated with these materials are sometimes called scree slopes or talus piles...
, which is talus finding its narrowest angle of repose
Angle of repose
The angle of repose or, more precisely, the critical angle of repose, of a granular material is the steepest angle of descent or dip of the slope relative to the horizontal plane when material on the slope face is on the verge of sliding. This angle is in the range 0°–90°.When bulk granular...
down-canyon. This is a "unique system involving ridgetop sinkhole
Sinkhole
A sinkhole, also known as a sink, shake hole, swallow hole, swallet, doline or cenote, is a natural depression or hole in the Earth's surface caused by karst processes — the chemical dissolution of carbonate rocks or suffosion processes for example in sandstone...
s and subterranean ice cave
Ice cave
The term ice cave refers to any type of natural cave that contains significant amounts of perennial ice...
s; this system also supports Maderate Cliffs." The valleys in which they occur tend to be very steep, and often have dense forest cover.
Climate
In summer, the cooler talus-covered slopes power an air exchange with sinkholes up atop the ridge, with warm air entering the sinkhole to an ice cave. The air is cooled and vented on the algific slope. In winter, the airflow is reversed. Cool or cold air is drawn through the algific talus into the ice cave, with flowing water or atmospheric humidity being turned to ice. The air temperature on these slopes ranges from "30 degrees F to 55 degrees F spring to fall".This causes a cooler, more moist summer environment than that which may occur a relatively short distance away. The result is a rather boreal ecosystem
Boreal ecosystem
The term boreal is usually applied to ecosystems localized in subarctic and subantarctic zones, although Austral is also used for the latter....
more associated with that found to the north at the Canadian border. It can also host relict populations not found elsewhere locally. "The vegetative community on algific talus slopes is different than the surrounding forest and typically contains ferns, mosses, liverwort
Marchantiophyta
The Marchantiophyta are a division of bryophyte plants commonly referred to as hepatics or liverworts. Like other bryophytes, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information....
s, evergreen species such as Canada yew and balsam fir
Balsam Fir
The balsam fir is a North American fir, native to most of eastern and central Canada and the northeastern United States .-Growth:It is a small to medium-size evergreen tree typically tall, rarely to tall, with a narrow conic crown...
, birch
Birch
Birch is a tree or shrub of the genus Betula , in the family Betulaceae, closely related to the beech/oak family, Fagaceae. The Betula genus contains 30–60 known taxa...
, basswood, and sugar maple
Sugar Maple
Acer saccharum is a species of maple native to the hardwood forests of northeastern North America, from Nova Scotia west to southern Ontario, and south to Georgia and Texas...
, and boreal disjunct herbs and ferns."
Distribution
The only sites in Wisconsin are "the Western Coulee and Ridges Ecological Landscape in western Grant County and are within a few miles of the Mississippi River".The great majority of the protected sites are closed to the general public, and in fact, are notably undocumented on the net, in order to keep them out of the eye of those who would vandalize them. One place that can be visited, however, is Bixby State Preserve
Bixby State Preserve
Bixby State Preserve is located in southwestern Clayton County, Iowa, about three miles north of Edgewood, Iowa. It is operated by the Iowa Department of Natural Resources....
, in northwestern Clayton County, Iowa
Clayton County, Iowa
-2010 census:The 2010 census recorded a population of 18,129 in the county, with a population density of . There were 8,999 housing units, of which 7,599 were occupied.-2000 census:...
.
Endangered and threatened species
The Iowa Pleistocene Snail was believed extinct until it was discovered on algific talus slopes in northeast Iowa in 1955. Placed on the Endangered Species List in 1977, Congress created the Driftless Area National Wildlife RefugeDriftless Area National Wildlife Refuge
Driftless Area National Wildlife Refuge is a United States National Wildlife Refuge in northeastern Iowa, southwestern Wisconsin and northwestern Illinois...
in 1989 to protect this species, as well as threatened and some relict species. Much of this refuge was carved out of pre-existing protected areas, most notably the Upper Mississippi River National Wildlife and Fish Refuge
Upper Mississippi River National Wildlife and Fish Refuge
The Upper Mississippi River National Wildlife and Fish Refuge is a . 261 river mile long National Wildlife Refuge located in and along the Upper Mississippi River. It runs from Wabasha, Minnesota in the north to Rock Island, Illinois in the south....
. The Northern monkshood is a threatened wildflower in the buttercup family (Ranunculaceae
Ranunculaceae
Ranunculaceae are a family of about 1700 species of flowering plants in about 60 genera, distributed worldwide....
) occurring in the Driftless Area as well as in New York State and receives similar protection.
External links
- Algific Talus Slope, Wisconsin Department of Natural ResourcesWisconsin Department of Natural ResourcesThe Wisconsin Department of Natural Resources is an agency of the state of Wisconsin. Its purpose is to preserve, protect, manage and maintain the natural resources of the state. The WDNR has the authority to set policy for itself and to recommend regulations for approval by the State Legislature...
, Retrieved July 24, 2007 - Mountain Maple Hollow, The Nature Conservancy of Iowa, Retrieved July 24, 2007
- Bill Witt, "An ecosystem frozen in time", Iowa Natural Heritage Foundation, Retrieved July 24, 2007