Ciénega De Ortiz
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A ciénega (also spelled ciénaga) is a wetland system unique to the
American Southwest The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural list of regions of the United States, region of the United States that includes Arizona and New Mexico, along with adjacen ...
and
Northern Mexico Northern Mexico ( ), commonly referred as , is an informal term for the northern cultural and geographical area in Mexico. Depending on the source, it contains some or all of the states of Baja California, Baja California Sur, Chihuahua (state), ...
. Ciénagas are
alkaline In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The ...
, freshwater, spongy,
wet meadow A wet meadow is a type of wetland with soils that are Solubility, saturated for part or all of the growing season which prevents the growth of trees and brush. Debate exists whether a wet meadow is a type of marsh or a completely separate type of ...
s with shallow-gradient, permanently saturated soils in otherwise arid landscapes that often occupy nearly the entire widths of valley bottoms. That description satisfies historic, pre-damaged ciénagas, although few can be described that way now. Incised ciénagas are common today. Ciénagas are usually associated with seeps or
spring Spring(s) may refer to: Common uses * Spring (season), a season of the year * Spring (device), a mechanical device that stores energy * Spring (hydrology), a natural source of water * Spring (mathematics), a geometric surface in the shape of a he ...
s, found in canyon headwaters or along margins of streams. Ciénagas often occur because the
geomorphology Geomorphology () is the scientific study of the origin and evolution of topographic and bathymetric features generated by physical, chemical or biological processes operating at or near Earth's surface. Geomorphologists seek to understand wh ...
forces water to the surface, over large areas, not merely through a single pool or channel. In a healthy ciénaga, water slowly migrates through long, wide-scale mats of thick, sponge-like wetland
sod Sod is the upper layer of turf that is harvested for transplanting. Turf consists of a variable thickness of a soil medium that supports a community of turfgrasses. In British and Australian English, sod is more commonly known as ''turf'', ...
. Ciénaga soils are squishy, permanently saturated, highly organic, black in color or anaerobic. Highly adapted sedges, rushes and
reed Reed or Reeds may refer to: Science, technology, biology, and medicine * Reed bird (disambiguation) * Reed pen, writing implement in use since ancient times * Reed (plant), one of several tall, grass-like wetland plants of the order Poales * Re ...
s are the dominant plants, with succession plants— Goodding's willow, Fremont cottonwoods and scattered Arizona walnuts—found on drier margins, down-valley in healthy ciénagas where water goes underground or along the banks of incised ciénagas. Ciénagas are not considered true swamps due to their lack of trees, which will drown in historic ciénagas. However, trees do grow in many damaged or drained ciénagas, making the distinction less clear.


Current state

The distribution and conservation status of ciénegas of Arizona and adjacent New Mexico were first inventoried and assessed systematically in 1985. Characterized by slow-moving, broad flows through extensive emergent vegetation, intact ciénegas were then rare, but reviews of historic accounts of the surface waters and landscapes of that region indicated they were previously extensive. Broadscale incision of ciénegas and conversion of large segments of former ciénegas to ephemeral surface flows through deeply incised former ciénega-formed soils, was hypothesized to have occurred predominantly in the late 1800s as a result of overgrazing, water diversions, and changing climates. More recent updates and geographically broadened inventories and status assessments of ciénegas now extend throughout Arizona and New Mexico eastward into Texas and south into Chihuahua and Sonora (México). Though often diverse local factors have clearly played major roles in altering some former ciénegas, the hypothesis of ongoing region-wide erosion since arrival of Europeans, and subsequent alteration of the land and aquifers (including more recent pumping of them), has been generally supported. "Since the late 1800s, natural wetlands in arid and semi-arid desert grasslands of the American Southwest and Northern Mexico have largely disappeared.". Historic ciénegas are now deeply entrenched and generally dry, or left with far less-permanent, often now ephemeral water. Broad grasslands adjacent to former ciénegas, once supported by shallow and stable groundwater maintained by ciénegas, are gone, replaced largely by mesquite and other arid-land vegetation, sometimes with narrow, remnant ciénegas persisting in deeply incised channels. Additional resources about ciénegas are available, including an extensive bibliography of relevant literature. File:San Solomon Ciénega.jpg, San Solomon Spring-fed ciénega, near Balmorhea, is in arid West Texas. The springs have a tremendous flow of 22 to 28 million gallons a day. (2009) File:1 - Healthy Cloverdale Cienaga.jpg, Cloverdale Ciénega in the Bootheel area of southwest New Mexico. This illustrates what an undamaged ciénaga looks like under normal conditions: marsh-like, broad, shallow, slow-migrating water through thick vegetation. (2008) File:1.5 Healthy Slightly Incised.jpg, Cienequita, Las Ciénegas, southeast of Tucson, Arizona. With very little incising, this is a smaller, functioning ciénaga. (2012) File:2- Healthy Cienaga after Flood.jpg, Canelo Hills, Arizona. This is what a healthy ciénaga looks like after a flood, erosion is avoided by plants that lie down and spring back after heavy flows. (2009) File:3 - Incised Cienaga-crop.jpg, Burro Ciénaga on the Pitchfork Ranch south of Silver City, New Mexico. Today, many of the few remaining ciénagas that still have water look like this, deeply incised by fast-flowing water trapped between vertical walls. (2005) File:4 - Narrow Incised Cienaga.jpg, Burro Ciénaga (2006) down channel about a quarter mile from the previous photograph. This section is shown more severely incised and creek-like: narrow rather than wide enough to cover the entire valley floor, but historically reaching the toes of the canyon on both sides. This ciénega has since been laboriously restored. File:5 - Dead Cienaga.jpg, Former San Simon Ciénega on the Arizona/New Mexico Border. Now dead, this ciénaga is beyond any possible recovery due to a serious water overdraft, despite a determined, long-term government effort. (2010)


Properties

Ciénegas occur at intermediate elevations (1000–2000 m) and are characterized by saturated, reducing soils with reliable water supply via seepage.
Sedges The Cyperaceae () are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large; botanists have described some 5,500 known species in about 90 generathe largest being the "true sedges" (genu ...
, rushes, and
grasses Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and species cultivated in ...
are the dominant plants, with a few trees that can withstand saturated soils, such as
willows Willows, also called sallows and osiers, of the genus ''Salix'', comprise around 350 species (plus numerous hybrids) of typically deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions. Most species are known ...
. Ciénegas trap organic matter from their surroundings, and are thus highly productive ecosystems. The structure of a natural ciénega is influenced by long-term climatic cycles of wet and dry periods. During dry periods, falling water tables lead to a reduction in vegetation. Prolonged wet periods lead to increased vegetation and trapping of sediment, while brief periods of high rainfall may lead to carving of gullies. Runaway gully growth, as can occur when vegetation is artificially removed (e.g., by overgrazing), can lead to channelization and loss of the ciénega.


Importance and conservation

As a primary source of water in arid environments, ciénegas support a broad range of terrestrial life, including numerous
endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...
. For instance, in Arizona, 19% of threatened, endangered, or candidate threatened or endangered species are directly associated with ciénegas. Ciénegas also purify surface water and mitigate flooding when heavy precipitation occurs, and help to cycle nutrients between water and soil. Humans have also long relied on the water provided by ciénegas: Indigenous Americans used ciénegas for water and hunting grounds, and a majority of pre-historic agricultural settlements occurred in the vicinity of ciénegas. Indigenous inhabitants of the American Southwest also gave spiritual significance to ciénegas and local watering holes. The decline of ciénegas has been caused largely by changes in land use, primarily overgrazing (which removes water-absorbing vegetation) and
overexploitation Overexploitation, also called overharvesting or ecological overshoot, refers to harvesting a renewable resource to the point of diminishing returns. Continued overexploitation can lead to the destruction of the resource, as it will be unable to ...
of ground water for agriculture and urban use. Direct removal of vegetation from the vicinity of wetlands has also been a cause of ciénega loss, as has the extirpation of
beaver Beavers (genus ''Castor'') are large, semiaquatic rodents of the Northern Hemisphere. There are two existing species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers are the second-large ...
from the region. Preservation of existing ciénegas, and restoration of degraded ciénegas, depends on reversing these trends in land use and preventing their recurrence in the vicinity of ciénegas. This preservation is complicated by the fact that a majority of ciénegas are found on privately-owned land, most of which do not have binding conservation agreements or easements in place.


Occurrence

It is likely that there were many hundreds of long lost ciénagas, although there are only 155 identified or named ciénagas since the European arrival in the entire International Four Corners Region of the Southwest — that is, Arizona and New Mexico in the United States and Chihuahua and Sonora in Mexico. The tables below (with minor updates from ) summarize current knowledge of the distribution and status of ciénegas in the indicated U.S. and Mexican states. In late 2018, as part of his effort to create a wetland action plan for the state of New Mexico, retired former New Mexico botanist Robert Sivinski discovered via satellite an additional 119 small ciénagas in New Mexico. This surprising number of previously unidentified or unstudied ciénagas suggests there may be more to be found. Further site-specific status assessment information and general information about ciénegas may be found in an open bibliography of ciénega literature.


See also

* * * * *


References


Further reading

* {{DEFAULTSORT:Cienega Topography Wetlands Springs (hydrology)