title: Constructed language

text: Renaissance interest in Ancient Egypt, notably the discovery of the "Hieroglyphica" of Horapollo, and first encounters with the Chinese script directed efforts towards a perfect written language. Johannes Trithemius, in "Steganographia" and "Polygraphia", attempted to show how all languages can be reduced to one. In the 17th century, interest in magical languages was continued by the Rosicrucians and alchemists (like John Dee and his Enochian). Jakob Boehme in 1623 spoke of a "natural language" ("Natursprache") of the senses.


title: Constructed language

text: Musical languages from the Renaissance were tied up with mysticism, magic and alchemy, sometimes also referred to as the language of the birds. The Solresol project of 1817 re-invented the concept in a more pragmatic context.


title: Constructed language

text: These early taxonomic conlangs produced systems of hierarchical classification that were intended to result in both spoken and written expression. Leibniz had a similar purpose for his "lingua generalis" of 1678, aiming at a lexicon of characters upon which the user might perform calculations that would yield true propositions automatically, as a side-effect developing binary calculus. These projects were not only occupied with reducing or modelling grammar, but also with the arrangement of all human knowledge into "characters" or hierarchies, an idea that with the Enlightenment would ultimately lead to the "Encyclopédie". Many of these 17th–18th centuries conlangs were pasigraphies, or purely written languages with no spoken form or a spoken form that would vary greatly according to the native language of the reader.


title: Constructed language

text: Leibniz and the encyclopedists realized that it is impossible to organize human knowledge unequivocally in a tree diagram, and consequently to construct an "a priori" language based on such a classification of concepts. Under the entry "Charactère", D'Alembert critically reviewed the projects of philosophical languages of the preceding century. After the "Encyclopédie", projects for "a priori" languages moved more and more to the lunatic fringe. Individual authors, typically unaware of the history of the idea, continued to propose taxonomic philosophical languages until the early 20th century (e.g. Ro), but most recent engineered languages have had more modest goals; some are limited to a specific field, like mathematical formalism or calculus (e.g. Lincos and programming languages), others are designed for eliminating syntactical ambiguity (e.g., Loglan and Lojban) or maximizing conciseness (e.g., Ithkuil).


title: Constructed language

text: Already in the "Encyclopédie" attention began to focus on "a posteriori" auxiliary languages. Joachim Faiguet de Villeneuve in the article on "Langue" wrote a short proposition of a "laconic" or regularized grammar of French. During the 19th century, a bewildering variety of such International Auxiliary Languages (IALs) were proposed, so that Louis Couturat and Léopold Leau in "Histoire de la langue universelle" (1903) reviewed 38 projects.


title: Constructed language

text: The first of these that made any international impact was Volapük, proposed in 1879 by Johann Martin Schleyer; within a decade, 283 Volapükist clubs were counted all over the globe. However, disagreements between Schleyer and some prominent users of the language led to schism, and by the mid-1890s it fell into obscurity, making way for Esperanto, proposed in 1887 by L. L. Zamenhof, and its descendants. Interlingua, the most recent auxlang to gain a significant number of speakers, emerged in 1951, when the International Auxiliary Language Association published its Interlingua–English Dictionary and an accompanying . The success of Esperanto did not stop others from trying to construct new auxiliary languages, such as Leslie Jones' Eurolengo, which mixes elements of English and Spanish.


title: Constructed language

text: Loglan (1955) and its descendants constitute a pragmatic return to the aims of the "a priori" languages, tempered by the requirement of usability of an auxiliary language. Thus far, these modern "a priori" languages have garnered only small groups of speakers.


title: Constructed language

text: Robot Interaction Language (2010) is a spoken language that is optimized for communication between machines and humans. The major goals of ROILA are that it should be easily learnable by the human user, and optimized for efficient recognition by computer speech recognition algorithms.


title: Constructed language

text: Artists may use language as a source of creativity in art, poetry, or calligraphy, or as a metaphor to address themes as cultural diversity and the vulnerability of the individual in a globalized world.


title: Constructed language

text: Some people prefer however to take pleasure in constructing, crafting a language by a conscious decision for reasons of literary enjoyment or aesthetic reasons without any claim of usefulness. Such artistic languages begin to appear in Early Modern literature (in Pantagruel, and in Utopian contexts), but they only seem to gain notability as serious projects beginning in the 20th century. "A Princess of Mars" (1912) by Edgar Rice Burroughs was possibly the first fiction of that century to feature a constructed language. J. R. R. Tolkien developed families of related fictional languages and discussed artistic languages publicly, giving a lecture entitled ""A Secret Vice"" in 1931 at a congress. (Orwell's Newspeak is considered a satire of an international auxiliary language rather than an artistic language proper.)


title: Constructed language

text: By the beginning of the first decade of the 21st century, it had become common for science-fiction and fantasy works set in other worlds to feature constructed languages, or more commonly, an extremely limited but defined vocabulary which "suggests" the existence of a complete language, or whatever portions of the language are needed for the story, and constructed languages are a regular part of the genre, appearing in "Star Wars", "Star Trek", "The Lord of the Rings" (Elvish), "Stargate SG-1", "", "Game of Thrones" (Dothraki language and Valyrian languages), "The Expanse", "Avatar", "Dune" and the "Myst" series of computer adventure games.


title: Constructed language

text: The matter of whether or not a constructed language can be owned or protected by intellectual property laws, or if it would even be possible to enforce those laws, is contentious.


title: Constructed language

text: In a 2015 lawsuit, CBS and Paramount Pictures challenged a fan film project called Axanar, stating the project infringed upon their intellectual property, which included the Klingon language, among other creative elements. During the controversy, Marc Okrand, the language's original designer expressed doubt as to whether Paramount's claims of ownership were valid.


title: Constructed language

text: David J. Peterson, a linguist who created multiple well-known constructed languages including the Valyrian languages and Dothraki, advocated a similar opinion, saying that "Theoretically, anyone can publish anything using any language I created, and, in my opinion, neither I nor anyone else should be able to do anything about it."


title: Constructed language

text: However, Peterson also expressed concern that the respective rights-holders—regardless of whether or not their ownership of the rights is legitimate—would be likely to sue individuals who publish material in said languages, especially if the author might profit from said material.


title: Constructed language

text: Furthermore, comprehensive learning material for such constructed languages as High Valyrian and Klingon has been published and made freely accessible on the language-learning platform Duolingo—but those courses are licensed by the respective copyright holders. Because only a few such disputes have occurred thus far, the legal consensus on ownership of languages remains uncertain.


title: Constructed language

text: The Tasmanian Aboriginal Center claims ownership of Palawa kani, an attempted composite reconstruction of up to a dozen extinct Tasmanian indigenous languages, and has asked Wikipedia to remove its page on the project. However, there is no current legal backing for the claim.


title: Constructed language

text: Various paper zines on constructed languages were published from the 1970s through the 1990s, such as "Glossopoeic Quarterly", "Taboo Jadoo", and "The Journal of Planned Languages".


title: Constructed language

text: The Conlang Mailing List was founded in 1991, and later split off an AUXLANG mailing list dedicated to international auxiliary languages. In the early to mid-1990s a few conlang-related zines were published as email or websites, such as "Vortpunoj" and "Model Languages". The Conlang mailing list has developed a community of conlangers with its own customs, such as translation challenges and translation relays, and its own terminology. Sarah Higley reports from results of her surveys that the demographics of the Conlang list are primarily men from North America and western Europe, with a smaller number from Oceania, Asia, the Middle East, and South America, with an age range from thirteen to over sixty; the number of women participating has increased over time.


title: Constructed language

text: More recently founded online communities include the Zompist Bulletin Board (ZBB; since 2001) and the Conlanger Bulletin Board. Discussion on these forums includes presentation of members' conlangs and feedback from other members, discussion of natural languages, whether particular conlang features have natural language precedents, and how interesting features of natural languages can be repurposed for conlangs, posting of interesting short texts as translation challenges, and meta-discussion about the philosophy of conlanging, conlangers' purposes, and whether conlanging is an art or a hobby. Another 2001 survey by Patrick Jarrett showed an average age of 30.65, with the average time since starting to invent languages 11.83 years. A more recent thread on the ZBB showed that many conlangers spend a relatively small amount of time on any one conlang, moving from one project to another; about a third spend years on developing the same language.


title: DeAndre Jordan

text: Hyland DeAndre Jordan Jr. (born July 21, 1988) is an American professional basketball player for the Denver Nuggets of the National Basketball Association (NBA). He played one season of college basketball for the Texas A&M Aggies.


title: DeAndre Jordan

text: Jordan was selected by the Los Angeles Clippers in the second round of the 2008 NBA draft with the 35th overall pick. He spent ten seasons with the Clippers before signing with the Dallas Mavericks in free agency in July 2018. He was traded to the New York Knicks in January 2019 and joined the Brooklyn Nets in July of the same year. He was dealt to the Detroit Pistons in September 2021 and reached a contract buyout agreement before signing with the Los Angeles Lakers in the same month. He was waived by the Lakers in March 2022 and subsequently joined the 76ers.


title: DeAndre Jordan

text: Jordan is a three-time All-NBA and two-time NBA All-Defensive Team member, and has twice led the league in rebounding. In 2017, he was named an NBA All-Star for the first time. , Jordan holds the NBA record for highest career field goal percentage at 67.31 percent. He is the Clippers' franchise leader in games played, rebounds, and blocks.


title: DeAndre Jordan

text: Jordan attended Episcopal High School through his junior year. Jordan averaged 15.0 points, 12.0 rebounds, and 4.0 blocks as a sophomore; and 16.5 points, 14.0 rebounds, and 7.0 blocks as a junior. Jordan transferred to Christian Life Center Academy for his senior year, where he averaged 26.1 points, 15.2 rebounds, and 8.1 blocks per game. He was a third-team "Parade" All-American, named to the first-team All-Greater Houston squad by the "Houston Chronicle" and was a two-time all-state selection. At Christian Life Center, Jordan posted a career-high 37 points in a game and also set the school record for most blocks in a game with 20.


title: DeAndre Jordan

text: Coming out of high school, Jordan was rated as the number-eight overall prospect, the number-two center in the country, and the number-one prep player in Texas by Rivals.com. Jordan was recruited by Florida, Florida State, Indiana, Texas, Texas A&M, LSU, Kentucky, and others.


title: DeAndre Jordan

text: In the summer of 2007, Jordan played for Team USA at the 2007 Under-19 World Championships in Serbia. Jordan played only nine minutes per game. The team finished second with an 8–1 record.


title: DeAndre Jordan

text: Before Jordan arrived at Texas A&M University in College Station, Aggies head basketball coach Billy Gillispie left the school to take the head coaching position at Kentucky. Jordan chose to honor his commitment to the university.


title: DeAndre Jordan

text: Jordan started 21 of 35 games in his freshman season at Texas A&M. He averaged 20 minutes and 1.3 blocks per game. In those games, he shot a team-high of 61.7 percent in field goals, but a team-low of 43.7 percent in free throws. Most of his field goals, however, were within a few feet from the basket. He finished the season averaging 7.9 points and 6.0 rebounds. He made the Big 12 All-Rookie Team for his efforts. After the season, he declared for the 2008 NBA draft.


title: DeAndre Jordan

text: Prior to the draft, draftexpress.com, a third-party NBA draft website, listed Jordan's strengths and weaknesses. A few strengths include "incredible physical specimen", "defensive potential", "incredible upside", and "freakish athlete". Some weaknesses include "not productive", "poor fundamentals", "mediocre footwork", and "high bust potential". The website also projected him to be picked at No. 16 by the Philadelphia 76ers. Other mock drafts had him projected to be picked at No. 10 by the New Jersey Nets or at No. 11 by the Indiana Pacers due to his attractive ability to run the floor. ESPN's Chad Ford had him going to the Memphis Grizzlies at pick No. 28 in the first round.


title: DeAndre Jordan

text: Jordan was selected with the 35th overall pick by the Los Angeles Clippers in the 2008 NBA draft. Due to injuries among the Clippers' low-post players, Jordan was pushed into the starting lineup for the January 19, 2009 game against the Minnesota Timberwolves. In his first game as a starter, he recorded six blocks, 10 rebounds, and eight points in 34 minutes of play. In the January 21, 2009 game against the Los Angeles Lakers, he played 43 minutes and recorded a career-high 23 points. This included 10 dunks, which had only been accomplished by two others players (Dwight Howard and Shaquille O'Neal) over the past 10 NBA seasons.


title: DeAndre Jordan

text: On December 11, 2011, Jordan signed an offer sheet with the Golden State Warriors reportedly worth $43 million over four years. However, one day later, the Clippers matched the offer to keep him.


title: DeAndre Jordan

text: For the 2011–12 season, Jordan changed his jersey number from 9 to 6. On December 25, 2011, Jordan recorded a career-high eight blocks against the Golden State Warriors in an opening day 105–86 victory.


title: DeAndre Jordan

text: During the 2012–13 season, Jordan's free-throw percentage dropped from 52.5% to 38.6%, one of his career worsts. However, he led the league in field-goal percentage, shooting 64.3%. This was his first season playing all 82 games.


title: DeAndre Jordan

text: In 2013, Jordan was selected to Team USA's minicamp in Las Vegas. On November 29, 2013, Jordan recorded a career-high nine blocks in the 104–98 victory against the Sacramento Kings. On January 3, 2014, Jordan scored a career-high 25 points in a 119–112 victory against the Dallas Mavericks. With 13.6 rebounds per game, he was the league's rebounding leader for the 2013–14 season.


title: DeAndre Jordan

text: On April 29, 2014, Jordan became the first NBA player with at least 25 points, 18 rebounds, and four blocked shots in a playoff game since Tim Duncan in 2008.


title: DeAndre Jordan

text: On February 9, 2015, Jordan recorded 22 points and a career-high 27 rebounds in the 115–98 win over the Dallas Mavericks. On March 13, in a 99–129 loss to the Dallas Mavericks, Jordan made his first career three-pointer early in the first quarter. On May 21, Jordan was named to the All-NBA third team. Jordan became the fifth player in NBA history to average at least 10 points, 15 rebounds, one steal, and two blocks during the regular season. It was last accomplished by Moses Malone during the 1982–83 season.


title: DeAndre Jordan

text: Despite verbally agreeing to sign a four-year, $80 million contract with the Dallas Mavericks on July 3, 2015, Jordan began having second thoughts just days later, and on July 8, a number of Clippers personnel flew to Houston for a meeting with Jordan to convince him to back out of his Mavericks deal. Hours later, Jordan officially re-signed with the Clippers on a four-year, $88 million contract.


title: DeAndre Jordan

text: On November 4, 2015, with 13 rebounds against the Golden State Warriors, Jordan became the Clippers' all-time leader in total rebounds, surpassing former Clipper Elton Brand (4,710), finishing the game with 4,711 career rebounds. On November 30, he recorded 18 points and a season-high 24 rebounds against the Portland Trail Blazers, but he also missed 22 free throws (12-of-34) to tie Wilt Chamberlain's NBA record and set a franchise record with 34 attempts. On January 13, he was sidelined for the team's game against the Miami Heat because of pneumonia, ending the NBA's longest active consecutive games played streak at 360.


title: DeAndre Jordan

text: Jordan helped the Clippers record a league-best 7–1 record to start the 2016–17 season. He played his 600th career game on November 9 against the Portland Trail Blazers, joining Randy Smith (715) and Eric Piatkowski (616) as the only players in franchise history to do so. On December 28, he recorded 13 points and a season-high 25 rebounds in a 102–98 loss to the New Orleans Pelicans. On January 14, 2017, he recorded a season-high 24 points and 21 rebounds in a 113–97 win over the Los Angeles Lakers. He surpassed that mark on January 19 with a career-high 29 points in a 104–101 loss to the Minnesota Timberwolves. On January 26, he was named a Western Conference All-Star reserve for the 2017 NBA All-Star Game, marking the first All-Star selection of his career. During the All-Star Weekend festivities, Jordan participated in the Slam Dunk Contest, but failed to make it past the first round.


title: DeAndre Jordan

text: In the Clippers' season opener on October 19, 2017, Jordan had 14 points and 24 rebounds in a 108–92 win over the Los Angeles Lakers. On January 4, 2018, he recorded a then season-high 26 points and 17 rebounds in a 127–117 loss to the Oklahoma City Thunder. On January 24, 2018, in a 113–102 loss to the Boston Celtics, Jordan tied Randy Smith (715) for most games played in team history. Two days later, in a 109–100 win over the Memphis Grizzlies, Jordan played his 716th game as a Clipper, surpassing Smith's record. On February 14, 2018, Jordan scored a career-high 30 points to go with 13 rebounds and four steals in a 129–119 win over the Celtics. On March 9, 2018, he had 20 points and 23 rebounds in a 116–102 win over the Cleveland Cavaliers. Jordan averaged 17.1 rebounds in March 2018, just shy of his career high of 17.3 set in March 2015.


title: DeAndre Jordan

text: On July 6, 2018, Jordan signed a one-year deal with the Dallas Mavericks. To begin the season, Jordan had three straight double-doubles, becoming the first Dallas player since Popeye Jones in 1994 to start a season with three straight. On October 28, he recorded 12 points, 19 rebounds and a career-high nine assists in a 113–104 loss to the Utah Jazz, thus recording his sixth double-double in six games to start the season. On November 7, he had 11 points and 12 rebounds in a 117–102 loss to the Jazz, thus collecting at least 10 rebounds for a franchise record 11th straight game. On November 19, he recorded 17 points and a then season-high 20 rebounds in a 98–88 loss to the Memphis Grizzlies. On December 2, he recorded 16 points and a season-high 23 rebounds in a 114–110 win over the Los Angeles Clippers. On December 16, he tied his season high with 23 rebounds in a 120–113 loss to the Sacramento Kings. He had 23 rebounds again on December 22 against the Golden State Warriors.


title: DeAndre Jordan

text: On January 31, 2019, Jordan was traded to the New York Knicks along with Dennis Smith Jr., Wesley Matthews and two future first round draft picks in exchange for Kristaps Porziņģis, Tim Hardaway Jr., Trey Burke and Courtney Lee. On March 15, he recorded 11 points, 13 rebounds and matched a career high with nine assists in a 109–83 loss to the San Antonio Spurs.


title: DeAndre Jordan

text: On July 6, 2019, the Brooklyn Nets signed Jordan to a reported four-year contract worth $40 million. On October 23, he made his debut for the Nets, recording two points, three rebounds, and one assist in 17 minutes of play during a 127–126 overtime loss to the Minnesota Timberwolves. On November 2, he recorded his first double-double of the season, scoring 10 points and 10 rebounds in a 113–109 loss to the Detroit Pistons. On December 21, Jordan logged a season-high 20 rebounds along with 12 points and six assists in a 122–112 win over the Atlanta Hawks. On February 20, 2020, he logged his tenth double-double of the season, grabbing 14 points and 15 rebounds in a 112–104 overtime loss to the Philadelphia 76ers. On June 29, 2020, Jordan announced that he had tested positive for COVID-19 and decided to opt out of playing in the season restart. He finished the 2019–20 season with 13 double-doubles, which was his lowest total since the 2012–13 season. However, he led the Nets in both field goal percentage and rebounds per game.


title: DeAndre Jordan

text: Jordan made his season debut for the Nets on December 22, 2020, where he logged four points, 11 rebounds, and one assist in a 125–99 win over the Golden State Warriors. On January 18, 2021, he recorded his first double-double of the season, scoring 12 points and 12 rebounds in a 125–123 win over the Milwaukee Bucks. On March 13, he scored a season-high 14 points along with nine rebounds and one block in a 100–95 win over the Detroit Pistons. On April 14, Jordan recorded a season-high 14 rebounds in a 117–123 loss to the Philadelphia 76ers. He did not play in the Nets' final 16 games of the season, and he did not appear at all in the playoffs. Jordan finished the season with only 6 double-doubles, which was his second-lowest season total, only behind his rookie season in 2008–09.


title: DeAndre Jordan

text: Center LaMarcus Aldridge retired in April 2021, but was medically cleared in September to keep playing, making a return to the Nets for Jordan unlikely. The team re-signed Aldridge on September 3.


title: DeAndre Jordan

text: On September 3, 2021, Jordan was traded to the Detroit Pistons in exchange for Sekou Doumbouya and Jahlil Okafor, and he reached a buyout agreement with the team four days later. On September 9, Jordan signed with the Los Angeles Lakers. On March 1, 2022, he was waived by the Lakers.


title: DeAndre Jordan

text: On March 3, 2022, Jordan signed with the Philadelphia 76ers, reuniting with former Clippers coach Doc Rivers and former Nets teammate James Harden.


title: DeAndre Jordan

text: Jordan is a Christian. Jordan prays frequently and has spoken about his faith saying, "I know my relationship with Christ, and I know what he has done for me, and that is what I live on." Jordan has a tattoo of Matthew 5:4–5 on his chest, a Christian cross on his left arm, the Serenity Prayer and his own message saying "I thank God for the gift that he has given me. I will honor, sacrifice, and dedicate myself to my talent. I know where I have come from but I know where I am going" on his right arm, and Philippians 4:13 with praying hands and "G.W.O.M" (God Watch Over Me) on his stomach.


title: DeAndre Jordan

text: His younger brother, Avery Jordan, became a professional football player in the Canadian Football League.


title: DeAndre Jordan

text: Jordan is a strong rebounder, averaging 10.6 rebounds per game in his career and leading the league in two seasons. He is also an excellent post-defender who averages 1.6 blocks per game for his career. Jordan's defensive play has even been compared to the defensive play of Bill Russell, a Hall of Fame center who is considered by many to be one of the greatest defenders and players of all time. On offense, he heavily relies on put-backs and alley-oops to score. He has led the league in field goal percentage in five seasons. However, he is a poor free throw shooter, making just 46% of his shots at the line, leading to opponents exploiting this weakness by intentionally fouling him with the Hack-a-Shaq strategy. Jordan is considered one of the more durable players in the NBA, having played in 360 straight games at one point.


title: Wetland

text: A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The primary factor that distinguishes wetlands from terrestrial land forms or water bodies is the characteristic vegetation of aquatic plants, adapted to the unique anoxic hydric soils. Wetlands are considered among the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal species. Methods for assessing wetland functions, wetland ecological health, and general wetland condition have been developed for many regions of the world. These methods have contributed to wetland conservation partly by raising public awareness of the functions some wetlands provide.


title: Wetland

text: Wetlands occur naturally on every continent. The water in wetlands is either freshwater, brackish or saltwater. The main wetland types are classified based on the dominant plants and/or the source of the water. For example, marshes are wetlands dominated by emergent vegetation such as reeds, cattails and sedges; swamps are ones dominated by woody vegetation such as trees and shrubs (although reed swamps in Europe are dominated by reeds, not trees). Examples of wetlands classified by their sources of water include tidal wetlands (oceanic tides), estuaries (mixed tidal and river waters), floodplains (excess water from overflowed rivers or lakes), springs, seeps and fens (groundwater discharge out onto the surface), and bogs and vernal ponds (rainfall or meltwater). Some wetlands have multiple types of plants and are fed by multiple sources of water, making them difficult to classify. The world's largest wetlands include the Amazon River basin, the West Siberian Plain, the Pantanal in South America, and the Sundarbans in the Ganges-Brahmaputra delta.


title: Wetland

text: Wetlands contribute a number of functions that benefit people. These are called ecosystem services and include water purification, groundwater replenishment, stabilization of shorelines and storm protection, water storage and flood control, processing of carbon (carbon fixation, decomposition and sequestration), other nutrients and pollutants, and support of plants and animals. Wetlands are reservoirs of biodiversity and provide wetland products. According to the UN Millennium Ecosystem Assessment, wetlands are more affected by environmental degradation than any other ecosystem on Earth. Wetlands can be important sources and sinks of carbon, depending on the specific wetland, and thus will play an important role in climate change and need to be considered in attempts to mitigate climate change. However, some wetlands are a significant source of methane emissions and some are also emitters of nitrous oxide. Constructed wetlands are designed and built to treat municipal and industrial wastewater as well as to divert stormwater runoff. Constructed wetlands may also play a role in water-sensitive urban design.


title: Wetland

text: A simplified definition of wetland is "an area of land that is usually saturated with water". More precisely, wetlands are areas where "water covers the soil, or is present either at or near the surface of the soil all year or for varying periods of time during the year, including during the growing season". A patch of land that develops pools of water after a rain storm would not necessarily be considered a "wetland", even though the land is wet. Wetlands have unique characteristics: they are generally distinguished from other water bodies or landforms based on their water level and on the types of plants that live within them. Specifically, wetlands are characterized as having a water table that stands at or near the land surface for a long enough period each year to support aquatic plants.


title: Wetland

text: Wetlands have also been described as ecotones, providing a transition between dry land and water bodies. Wetlands exist "...at the interface between truly terrestrial ecosystems and aquatic systems, making them inherently different from each other, yet highly dependent on both."


title: Wetland

text: In environmental decision-making, there are subsets of definitions that are agreed upon to make regulatory and policy decisions.


title: Wetland

text: An ecological definition of a wetland is "an ecosystem that arises when inundation by water produces soils dominated by anaerobic and aerobic processes, which, in turn, forces the biota, particularly rooted plants, to adapt to flooding".


title: Wetland

text: Sometimes a precise legal definition of a wetland is required. The definition used for regulation by the United States government is: 'The term "wetlands" means those areas that are inundated or saturated by surface or ground water at a frequency and duration to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally included swamps, marshes, bogs, and similar areas.'


title: Wetland

text: For each of these definitions and others, regardless of the purpose, hydrology is emphasized (shallow waters, water-logged soils). The soil characteristics and the plants and animals controlled by the wetland hydrology are often additional components of the definitions.


title: Wetland

text: Wetlands can be tidal (inundated by tides) or non-tidal. The water in wetlands is either freshwater, brackish, or saltwater. There are four main kinds of wetlands – marsh, swamp, bog and fen (bogs and fens being types of peatlands or mires). Some experts also recognize wet meadows and aquatic ecosystems as additional wetland types. Sub-types include mangrove forests, carrs, pocosins, floodplains, peatlands, vernal pools, sinks, and many others.


title: Wetland

text: The following three groups are used within Australia to classify wetland by type: Marine and coastal zone wetlands, inland wetlands and human-made wetlands. In the US, the best known classifications are the Cowardin classification system and the hydrogeomorphic (HGM) classification system. The Cowardin system includes five main types of wetlands: marine (ocean-associated); estuarine (mixed ocean- and river-associated); riverine (within river channels); lacustrine (lake-associated); and palustrine (inland nontidal habitats).


title: Wetland

text: Peatlands are a unique kind of wetland where lush plant growth and slow decay of dead plants (under anoxic conditions) results in organic peat accumulating; bogs, fens, and mires are different names for peatlands.


title: Wetland

text: Some wetlands have localized names unique to a region such as the prairie potholes of North America's northern plain, pocosins, Carolina bays and baygalls of the Southeastern US, mallines of Argentina, Mediterranean seasonal ponds of Europe and California, turloughs of Ireland, billabongs of Australia, among many others.


title: Wetland

text: Wetlands are found throughout the world in different climates. Temperatures vary greatly depending on the location of the wetland. Many of the world's wetlands are in the temperate zones, midway between the North or South Poles and the equator. In these zones, summers are warm and winters are cold, but temperatures are not extreme. In subtropical zone wetlands, such as along the Gulf of Mexico, average temperatures might be . Wetlands in the tropics are subjected to much higher temperatures for a large portion of the year. Temperatures for wetlands on the Arabian Peninsula can exceed and these habitats would therefore be subject to rapid evaporation. In northeastern Siberia, which has a polar climate, wetland temperatures can be as low as . Peatlands in arctic and subarctic regions insulate the permafrost, thus delaying or preventing its thawing during summer, as well as inducing its formation.


title: Wetland

text: The amount of precipitation a wetland receives varies widely according to its area. Wetlands in Wales, Scotland, and western Ireland typically receive about per year. In some places in Southeast Asia, where heavy rains occur, they can receive up to . In some drier regions, wetlands exist where as little as precipitation occurs each year.


title: Wetland

text: Wetlands vary widely due to local and regional differences in topography, hydrology, vegetation, and other factors, including human involvement. Other important factors include fertility, natural disturbance, competition, herbivory, burial and salinity. When peat accumulates, bogs and fens arise.


title: Wetland

text: The most important factor producing wetlands is hydrology, or flooding. The duration of flooding or prolonged soil saturation by groundwater determines whether the resulting wetland has aquatic, marsh or swamp vegetation. Other important factors include soil fertility, natural disturbance, competition, herbivory, burial, and salinity. When peat from dead plants accumulates, bogs and fens develop.


title: Wetland

text: Wetland hydrology is associated with the spatial and temporal dispersion, flow, and physio-chemical attributes of surface and ground waters. Sources of hydrological flows into wetlands are predominantly precipitation, surface water (saltwater or freshwater), and groundwater. Water flows out of wetlands by evapotranspiration, surface flows and tides, and subsurface water outflow. Hydrodynamics (the movement of water through and from a wetland) affects hydro-periods (temporal fluctuations in water levels) by controlling the water balance and water storage within a wetland.


title: Wetland

text: Landscape characteristics control wetland hydrology and water chemistry. The O and CO concentrations of water depend on temperature, atmospheric pressure and mixing with the air (from winds or water flows). Water chemistry within wetlands is determined by the pH, salinity, nutrients, conductivity, soil composition, hardness, and the sources of water. Water chemistry varies across landscapes and climatic regions. Wetlands are generally minerotrophic (waters contain dissolved materials from soils) with the exception of ombrotrophic bogs that are fed only by water from precipitation.


title: Wetland

text: Because bogs receive most of their water from the atmosphere, their water usually has low mineral ionic composition. In contrast, wetlands fed by groundwater or tides have a higher concentration of dissolved nutrients and minerals.


title: Wetland

text: Fen peatlands receive water both from precipitation and ground water in varying amounts so their water chemistry ranges from acidic with low levels of dissolved minerals to alkaline with high accumulation of calcium and magnesium.


title: Wetland

text: Salinity has a strong influence on wetland water chemistry, particularly in coastal wetlands and in arid and semiarid regions with large precipitation deficits. Natural salinity is regulated by interactions between ground and surface water, which may be influenced by human activity.


title: Wetland

text: Carbon is the major nutrient cycled within wetlands. Most nutrients, such as sulfur, phosphorus, carbon, and nitrogen are found within the soil of wetlands. Anaerobic and aerobic respiration in the soil influences the nutrient cycling of carbon, hydrogen, oxygen, and nitrogen, and the solubility of phosphorus thus contributing to the chemical variations in its water. Wetlands with low pH and saline conductivity may reflect the presence of acid sulfates and wetlands with average salinity levels can be heavily influenced by calcium or magnesium. Biogeochemical processes in wetlands are determined by soils with low redox potential. Wetland soils are identified by redoxymorphic mottles (often from iron oxide rust) or low chroma intensity, as determined by the Munsell Color System.


title: Wetland

text: Due to the low dissolved oxygen (DO) content, and relatively low nutrient balance of wetland environments, most wetlands are very susceptible to alterations in water chemistry. Key factors that are assessed to determine water quality include:


title: Wetland

text: These chemical factors can be used to quantify wetland disturbances, and often provide information as to whether a wetland is fed by precipitation, surface water or groundwater, due to the different ion characteristics of the different water sources. Wetlands are adept at impacting the water chemistry of streams or water bodies that interact with them, and can process ions that result from water pollution such as acid mine drainage or urban runoff.,


title: Wetland

text: The biota of a wetland system includes its plants (flora) and animals (fauna) and microbes (bacteria, fungi). The most important factor affecting the biota is the hydroperiod, or the duration of flooding. Other important factors include fertility and salinity of the water or soils. The chemistry of water flowing into wetlands depends on the source of water, the geological material that it flows through and the nutrients discharged from organic matter in the soils and plants at higher elevations. Biota may vary within a wetland seasonally or in response to flood regimes.


title: Wetland

text: Submerged wetland vegetation can grow in saline and fresh-water conditions. Some species have underwater flowers, while others have long stems to allow the flowers to reach the surface. Submerged species provide a food source for native fauna, habitat for invertebrates, and also possess filtration capabilities. Examples include seagrasses and eelgrass.


title: Wetland

text: Floating water plants or floating vegetation are usually small, like those in the Lemnoideae subfamily (duckweeds).


title: Wetland

text: Emergent vegetation like the cattails ("Typha" spp.), sedges ("Carex" spp.) and arrow arum ("Peltandra virginica") rise above the surface of the water.


title: Wetland

text: When trees and shrubs comprise much of the plant cover in saturated soils, those areas in most cases are called swamps. The upland boundary of swamps is determined partly by water levels. This can be affected by dams Some swamps can be dominated by a single species, such as silver maple swamps around the Great Lakes. Others, like those of the Amazon basin, have large numbers of different tree species. Other examples include cypress ("Taxodium") and mangrove swamps.


title: Wetland

text: Many species of fish are highly dependent on wetland ecosystems. Seventy-five percent of the United States' commercial fish and shellfish stocks depend solely on estuaries to survive. Tropical fish species need mangroves for critical hatchery and nursery grounds and the coral reef system for food.


title: Wetland

text: Amphibians such as frogs and salamanders need both terrestrial and aquatic habitats in which to reproduce and feed. Because amphibians often inhabit depressional wetlands like prairie potholes and Carolina bays, the connectivity among these isolated wetlands is an important control of regional populations. While tadpoles feed on algae, adult frogs forage on insects. Frogs are sometimes used as an indicator of ecosystem health because their thin skin permits absorption of nutrients and toxins from the surrounding environment resulting in increased extinction rates in unfavorable and polluted environmental conditions.


title: Wetland

text: Reptiles such as snakes, lizards, turtles, alligators and crocodiles are common in wetlands of some regions. In freshwater wetlands of the Southeastern US, alligators are common and a freshwater species of crocodile occurs in South Florida. The Florida Everglades is the only place in the world where both crocodiles and alligators coexist. The saltwater crocodile inhabits estuaries and mangroves and can be seen along the Eastern coastline of Australia. Snapping turtles are one of the many kinds of turtles found in wetlands.


title: Wetland

text: Mammals of wetlands include numerous small and medium-sized species such as voles, bats, muskrats and platypus in addition to large herbivorous and apex predator species such as the beaver, coypu, swamp rabbit, Florida panther, and moose. Wetlands attract many mammals due to abundant seeds, berries, and other vegetation as food for herbivores, as well as abundant populations of invertebrates, small reptiles and amphibians as prey for predators.


title: Wetland

text: Invertebrates of wetlands include aquatic insects (such as dragonflies, aquatic bugs and beetles, midges, mosquitoes), crustaceans (such as crabs, crayfish, shrimps, microcrustaceans), mollusks (such as clams, mussels, snails), and worms (such as polychaetes, oligochaetes, leeches), among others. Invertebrates comprise more than half of the known animal species in wetlands, and are considered the primary food web link between plants and higher animals (such as fish and birds). The low oxygen conditions in wetland water and their frequent flooding and drying (daily in tidal wetlands, seasonally in temporary ponds and floodplains) prevent many invertebrates from inhabiting wetlands, and thus the invertebrate fauna of wetlands is often less diverse than some other kinds of habitat (such as streams, coral reefs, and forests). Some wetland invertebrates thrive in habitats that lack predatory fish. Many insects only inhabit wetlands as aquatic immatures (nymphs, larvae) and the flying adults inhabit upland habitats, returning to the wetlands to lay eggs. For instance, a common hoverfly "Syritta pipiens" inhabits wetlands as larvae (maggots), living in wet, rotting organic matter; these insects then visit terrestrial flowers as adult flies.


title: Wetland

text: Algae are diverse plant-like organisms that can vary in size, color, and shape. Algae occur naturally in habitats such as inland lakes, inter-tidal zones, and damp soil and provide a food source for many animals, including some invertebrates, fish, turtles, and frogs. There are several groups of algae:


title: Wetland

text: Wetlands, the functions and services they provide as well as their flora and fauna, can be affected by several types of disturbances. The disturbances (sometimes termed stressors or alterations) can be human-associated or natural, direct or indirect, reversible or not, and isolated or cumulative. Disturbances exceed the levels or patterns normally found within wetlands of a particular class in a particular region. Predominant disturbances of wetlands include:


title: Wetland

text: Biodiversity loss occurs in wetland systems through land use changes, habitat destruction, pollution, exploitation of resources, and invasive species. Vulnerable, threatened, and endangered species include 17% of waterfowl, 38% of fresh-water dependent mammals, 33% of freshwater fish, 26% of freshwater amphibians, 72% of freshwater turtles, 86% of marine turtles, 43% of crocodilians and 27% of coral reef-building species. Introduced aquatic plants in different wetland systems can have large impacts. The introduction of water hyacinth, a native plant of South America into Lake Victoria in East Africa as well as duckweed into non-native areas of Queensland, Australia, have overtaken entire wetland systems overwhelming the habitats and reducing the diversity of native plants and animals. This is largely due to the phenomenal growth rates of the plants and their ability to float and grow across the entire surface of the water.


title: Wetland

text: Due to their productivity, wetlands are often converted into dry land with dykes and drains and used for agricultural purposes. The construction of dykes, and dams, has negative consequences for individual wetlands and entire watersheds. Their proximity to lakes and rivers means that they are often developed for human settlement. Once settlements are constructed and protected by dykes, the settlements then become vulnerable to land subsidence and ever increasing risk of flooding. The Mississippi River Delta around New Orleans, Louisiana is a well-known example; the Danube Delta in Europe is another.


title: Wetland

text: Depending on a wetland's geographic and topographic location, the functions it performs can support multiple ecosystem services, values, or benefits. United Nations Millennium Ecosystem Assessment and Ramsar Convention described wetlands as a whole to be of biosphere significance and societal importance in the following areas:


title: Wetland

text: The economic worth of the ecosystem services provided to society by intact, naturally functioning wetlands is frequently much greater than the perceived benefits of converting them to 'more valuable' intensive land use – particularly as the profits from unsustainable use often go to relatively few individuals or corporations, rather than being shared by society as a whole.


title: Wetland

text: "Unless otherwise cited, ecosystem services information is based on the following series of references."


title: Wetland

text: To replace these wetland ecosystem services, enormous amounts of money would need to be spent on water purification plants, dams, levees, and other hard infrastructure, and many of the services are impossible to replace.


title: Wetland

text: Floodplains and closed-depression wetlands can provide the functions of storage reservoirs and flood protection.


title: Wetland

text: The wetland system of floodplains is formed from major rivers downstream from their headwaters. "The floodplains of major rivers act as natural storage reservoirs, enabling excess water to spread out over a wide area, which reduces its depth and speed. Wetlands close to the headwaters of streams and rivers can slow down rainwater runoff and spring snowmelt so that it doesn't run straight off the land into water courses. This can help prevent sudden, damaging floods downstream." Notable river systems that produce wide floodplains include the Nile River, the Niger river inland delta, the Zambezi River flood plain, the Okavango River inland delta, the Kafue River flood plain, the Lake Bangweulu flood plain (Africa), Mississippi River (USA), Amazon River (South America), Yangtze River (China), Danube River (Central Europe) and Murray-Darling River (Australia).


title: Wetland

text: Drainage of floodplains or development activities that narrow floodplain corridors (such as the construction of levees) reduces the ability of coupled river-floodplain systems to control flood damage. That is because modified and less expansive systems must still manage the same amount of precipitation, causing flood peaks to be higher or deeper and floodwaters to travel faster.


title: Wetland

text: Water management engineering developments in the past century have degraded floodplain wetlands through the construction of artificial embankments such as dykes, bunds, levees, weirs, barrages and dams. All concentrate water into a main channel and waters that historically spread slowly over a large, shallow area are concentrated. Loss of wetland floodplains results in more severe and damaging flooding. Catastrophic human impact in the Mississippi River floodplains was seen in death of several hundred individuals during a levee breach in New Orleans caused by Hurricane Katrina. Human-made embankments along the Yangtze River floodplains have caused the main channel of the river to become prone to more frequent and damaging flooding. Some of these events include the loss of riparian vegetation, a 30% loss of the vegetation cover throughout the river's basin, a doubling of the percentage of the land affected by soil erosion, and a reduction in reservoir capacity through siltation build-up in floodplain lakes.


title: Wetland

text: Groundwater replenishment can be achieved for example by marsh, swamp, and subterranean karst and cave hydrological systems.


title: Wetland

text: The surface water visibly seen in wetlands only represents a portion of the overall water cycle, which also includes atmospheric water (precipitation) and groundwater. Many wetlands are directly linked to groundwater and they can be a crucial regulator of both the quantity and quality of water found below the ground. Wetlands that have permeable substrates like limestone or occur in areas with highly variable and fluctuating water tables have especially important roles in groundwater replenishment or water recharge. Substrates that are porous allow water to filter down through the soil and underlying rock into aquifers which are the source of much of the world's drinking water. Wetlands can also act as recharge areas when the surrounding water table is low and as a discharge zone when it is high. Karst (cave) systems are a unique example of this system and can be a connection of underground rivers influenced by rain and other forms of precipitation to the surface.


title: Wetland

text: Tidal and inter-tidal wetland systems protect and stabilize coastal zones. Coral reefs provide a protective barrier to coastal shoreline. Mangroves stabilize the coastal zone from the interior and will migrate with the shoreline to remain adjacent to the boundary of the water. The main conservation benefit these systems have against storms and storm surges is the ability to reduce the speed and height of waves and floodwaters.


title: Wetland

text: The number of people who live and work near the coast is expected to grow immensely over the next fifty years. From an estimated 200 million people that currently live in low-lying coastal regions, the development of urban coastal centers is projected to increase the population by fivefold within 50 years.


title: Wetland

text: The United Kingdom has begun the concept of managed coastal realignment. This management technique provides shoreline protection through restoration of natural wetlands rather than through applied engineering. In East Asia, reclamation of coastal wetlands has resulted in widespread transformation of the coastal zone, and up to 65% of coastal wetlands have been destroyed by coastal development. One analysis using the impact of hurricanes versus storm protection provided naturally by wetlands projected the value of this service at US$33,000/hectare/year.


title: Wetland

text: Water purification can be provided by floodplains, closed-depression wetlands, mudflat, freshwater marsh, salt marsh, mangroves.


title: Wetland

text: Nutrient retention: Wetlands cycle both sediments and nutrients, sometimes serving as buffers between terrestrial and aquatic ecosystems. A natural function of wetland vegetation is the up-take, storage, and (for nitrate) the removal of nutrients found in runoff water from the surrounding landscapes. In many wetlands, microbial processes convert soluble nutrients to a gaseous form, such as denitrification of nitrate, which then moves the nitrate to the atmosphere mostly as harmless nitrogen gas.


title: Wetland

text: Sediment and heavy metal traps: Precipitation and surface runoff induces soil erosion, transporting sediment in suspension into and through waterways. These sediments move towards larger and more sizable waterways through a natural process that moves water towards oceans. All types of sediments whether composed of clay, silt, sand or gravel and rock can be carried into wetland systems through erosion. Wetland vegetation acts as a physical barrier to slow water flow and then trap sediment for both short or long periods of time. Suspended sediment can contain heavy metals that are also retained when wetlands trap the sediment. In some cases, certain metals are taken up through wetland plant stems, roots, and leaves. For example, many floating plant species such as water hyacinth ("Eichhornia crassipes"), duckweed ("Lemna") and water fern ("Azolla") store iron and copper found in wastewater; these plants also extract pathogens. Fast-growing plants rooted in the soils of wetlands such as cattail ("Typha") and reed ("Phragmites") also contribute to heavy metal up-take. Animals such as the oyster can filter more than of water per day while grazing for food, removing nutrients, suspended sediments, and chemical contaminants in the process. On the other hand, some types of wetlands facilitate the mobilization and bioavailability of mercury (another heavy metal), which in its methyl mercury form increases the risk of bioaccumulation in fish important to animal food webs and harvested for human consumption.


title: Wetland

text: Capacity: The ability of wetland systems to store or remove nutrients and trap sediment and associated metals is highly efficient and effective but each system has a threshold. An overabundance of nutrient input from fertilizer run-off, sewage effluent, or non-point pollution will cause eutrophication. Upstream erosion from deforestation can overwhelm wetlands making them shrink in size and cause dramatic biodiversity loss through excessive sedimentation load. Retaining high levels of metals in sediments is problematic if the sediments become resuspended or oxygen and pH levels change at a future time. The capacity of wetland vegetation to store heavy metals depends on the particular metal, oxygen and pH status of wetland sediments and overlying water, water flow rate (detention time), wetland size, season, climate, type of plant, and other factors.


title: Wetland

text: The capacity of a wetland to store sediment, nutrients, and metals can be diminished if sediments are compacted such as by vehicles or heavy equipment, or are regularly tilled. Unnatural changes in water levels and water sources also can affect the water purification function. If water purification functions are impaired, excessive loads of nutrients enter waterways and cause eutrophication. This is of particular concern in temperate coastal systems. The main sources of coastal eutrophication are industrially made nitrogen, which is used as fertilizer in agricultural practices, as well as septic waste runoff. Nitrogen is the limiting nutrient for photosynthetic processes in saline systems, however in excess, it can lead to an overproduction of organic matter that then leads to hypoxic and anoxic zones within the water column. Without oxygen, other organisms cannot survive, including economically important finfish and shellfish species.


title: Wetland

text: Constructed wetlands are built for wastewater treatment.An example of how a natural wetland is used to provide some degree of sewage treatment is the East Kolkata Wetlands in Kolkata, India. The wetlands cover , and are used to treat Kolkata's sewage. The nutrients contained in the wastewater sustain fish farms and agriculture.


title: Wetland

text: Wetland systems' rich biodiversity has becoming a focal point catalysed by the Ramsar Convention and World Wildlife Fund. The impact of maintaining biodiversity is seen at the local level through job creation, sustainability, and community productivity. A good example is the Lower Mekong basin which runs through Cambodia, Laos, and Vietnam, supporting over 55 million people.


title: Wetland

text: Biodiverse river basins: The Amazon holds more than 3,000 species of freshwater fish species within the boundaries of its basin. Fishes consuming fallen fruit, e.g., the large-bodied characid, "Colossoma macropomum" enter the Amazonian floodplains during annual floods egesting viable seeds thus acting as an important agent of dispersal. A key species which is overfished, the Piramutaba catfish, "Brachyplatystoma vaillantii", migrates more than from its nursery grounds near the mouth of the Amazon River to its spawning grounds in Andean tributaries, above sea level, distributing plants seed along the route.


title: Wetland

text: Productive intertidal zones: Intertidal mudflats have a level of productivity similar to that of some wetlands even while possessing a low number of species. The abundance of invertebrates found within the mud are a food source for migratory waterfowl.


title: Wetland

text: Critical life-stage habitat: Mudflats, saltmarshes, mangroves, and seagrass beds have high levels of both species richness and productivity, and are home to important nursery areas for many commercial fish stocks.


title: Wetland

text: Genetic diversity: Populations of many species are confined geographically to only one or a few wetland systems, often due to the long period of time that the wetlands have been physically isolated from other aquatic sources. For example, the number of endemic species in the Selenga River Delta of Lake Baikal in Russia classifies it as a hotspot for biodiversity and one of the most biodiverse wetlands in the entire world.


title: Wetland

text: Wetland productivity is linked to the climate, wetland type, and nutrient availability. Low water and occasional drying of the wetland bottom during droughts (dry marsh phase) stimulates plant recruitment from a diverse seed bank and increases productivity by mobilizing nutrients. In contrast, high water during deluges (lake marsh phase) causes turnover in plant populations and increases open water, but lowers overall productivity. From open water to complete vegetation cover, annual net primary productivity may vary 20-fold. The grasses of fertile floodplains such as the Nile can be highly productive, especially plants such as "Arundo donax" (giant reed), "Cyperus papyrus" (papyrus), "Phragmites" (reed) and "Typha" (cattail).


title: Wetland

text: Wetlands naturally produce an array of vegetation and other ecological products that can be harvested for personal and commercial use. Many fishes have all or part of their life-cycle occurring within a wetland system. Fresh and saltwater fish are the main source of protein for about one billion people and comprise 15% of an additional 3.5 billion people's protein intake. Another food staple found in wetland systems is rice, a popular grain that is consumed at the rate of one fifth of the total global calorie count. In Bangladesh, Cambodia and Vietnam, where rice paddies are predominant on the landscape, rice consumption reach 70%. Some native wetland plants in the Caribbean and Australia are harvested sustainably for medicinal compounds; these include the red mangrove ("Rhizophora mangle") which possesses antibacterial, wound-healing, anti-ulcer effects, and antioxidant properties.


title: Wetland

text: The nipa palm of Asia (sugar, vinegar, alcohol, and fodder) and honey collection from mangroves contribute to human diets and people's income. Coastal Thailand villages earn the key portion of their income from sugar production while Cuba relocates thousands of beehives each year to track the seasonal flowering of the mangrove "Avicennia". Other mangrove-derived products include fuelwood, salt (produced by evaporating seawater), animal fodder, traditional medicines (e.g. from mangrove bark), fibers for textiles and dyes and tannins.


title: Wetland

text: Over-fishing is a major problem for sustainable use of wetlands. Concerns are developing over certain aspects of farm fishing, which uses natural wetlands and waterways to harvest fish for human consumption. Aquaculture is continuing to develop rapidly throughout the Asia-Pacific region especially in China where 90% of the total number of aquaculture farms occur, contributing 80% of global value. Some aquaculture has eliminated massive areas of wetland through practices such as the shrimp farming industry's destruction of mangroves. Even though the damaging impact of large-scale shrimp farming on the coastal ecosystem in many Asian countries has been widely recognized for quite some time now, it has proved difficult to mitigate since other employment avenues for people are lacking. Also burgeoning demand for shrimp globally has provided a large and ready market.


title: Wetland

text: Some types of wetlands can serve as fire breaks that help slow the spread of minor wildfires. Larger wetland systems can influence local precipitation patterns. Some boreal wetland systems in catchment headwaters may help extend the period of flow and maintain water temperature in connected downstream waters. Pollination services are supported by many wetlands which may provide the only suitable habitat for pollinating insects, birds, and mammals in highly developed areas.


title: Wetland

text: Wetlands have historically subjected to large draining efforts for development (real estate or agriculture), and flooding to create recreational lakes or generate hydropower. Some of the world's most important agricultural areas were wetlands that have been converted to farmland. Since the 1970s, more focus has been put on preserving wetlands for their natural functions. Since 1900 between 65-70% of the world's wetlands have been lost. In order to maintain wetlands and sustain their functions, alterations and disturbances that are outside the normal range of variation should be minimized.


title: Wetland

text: Wetlands are vital ecosystems that enhance the livelihoods for the millions of people who live in and around them. The Millennium Development Goals (MDGs) called for different sectors to join forces to secure wetland environments in the context of sustainable development and improving human wellbeing. Studies have shown that it is possible to conserve wetlands while improving the livelihoods of people living among them. Case studies conducted in Malawi and Zambia looked at how dambos – wet, grassy valleys or depressions where water seeps to the surface – can be farmed sustainably. Project outcomes included a high yield of crops, development of sustainable farming techniques, and water management strategies that generate enough water for irrigation.


title: Wetland

text: "The Convention on Wetlands of International Importance, especially as Waterfowl Habitat", or Ramsar Convention, is an international treaty designed to address global concerns regarding wetland loss and degradation. The primary purposes of the treaty are to list wetlands of international importance and to promote their wise use, with the ultimate goal of preserving the world's wetlands. Methods include restricting access to some wetland areas, as well as educating the public to combat the misconception that wetlands are wastelands. The Convention works closely with five International Organisation Partners (IOPs). These are: Birdlife International, the IUCN, the International Water Management Institute, Wetlands International and the World Wide Fund for Nature. The partners provide technical expertise, help conduct or facilitate field studies and provide financial support. The IOPs also participate regularly as observers in all meetings of the Conference of the Parties and the Standing Committee and as full members of the Scientific and Technical Review Panel.


title: Wetland

text: Restoration and restoration ecologists intend to return wetlands to their natural trajectory by aiding directly with the natural processes of the ecosystem. These direct methods vary with respect to the degree of physical manipulation of the natural environment and each are associated with different levels of restoration. Restoration is needed after disturbance or perturbation of a wetland. Disturbances include exogenous factors such as flooding or drought. Other external damage may be anthropogenic disturbance caused by clear-cut harvesting of trees, oil and gas extraction, poorly defined infrastructure installation, over grazing of livestock, ill-considered recreational activities, alteration of wetlands including dredging, draining, and filling, and other negative human impacts. Disturbance puts different levels of stress on an environment depending on the type and duration of disturbance. There is no one way to restore a wetland and the level of restoration required will be based on the level of disturbance although, each method of restoration does require preparation and administration.


title: Wetland

text: Factors influencing selected approach may include budget, time scale limitations, project goals, level of disturbance, landscape and ecological constraints, political and administrative agendas and socioeconomic priorities.


title: Wetland

text: For this strategy, there is no biophysical manipulation and the ecosystem is left to recover based on the process of succession alone. The focus is to eliminate and prevent further disturbance from occurring and for this type of restoration requires prior research to understand the probability that the wetland will recover naturally. This is likely to be the first method of approach since it is the least intrusive and least expensive although some biophysical non-intrusive manipulation may be required to enhance the rate of succession to an acceptable level. Example methods include prescribed burns to small areas, promotion of site specific soil microbiota and plant growth using nucleation planting whereby plants radiate from an initial planting site, and promotion of niche diversity or increasing the range of niches to promote use by a variety of different species. These methods can make it easier for the natural species to flourish by removing environmental impediments and can speed up the process of succession.


title: Wetland

text: For this strategy, a mixture of natural regeneration and manipulated environmental control is used. This may require some engineering, and more intensive biophysical manipulations including ripping of subsoil, agrichemical applications of herbicides or insecticides, laying of mulch, mechanical seed dispersal, and tree planting on a large scale. In these circumstances the wetland is impaired and without human assistance it would not recover within an acceptable period of time as determined by ecologists. Methods of restoration used will have to be determined on a site by site basis as each location will require a different approach based on levels of disturbance and the local ecosystem dynamics.


title: Wetland

text: This most expensive and intrusive method of reconstruction requires engineering and ground up reconstruction. Because there is a redesign of the entire ecosystem it is important that the natural trajectory of the ecosystem be considered and that the plant species promoted will eventually return the ecosystem towards its natural trajectory.


title: Wetland

text: In Southeast Asia, peatswamp forests and soils are being drained, burnt, mined, and overgrazed, contributing to climate change. As a result of peat drainage, the organic carbon that had built up over thousands of years and is normally under water is suddenly exposed to the air. The peat decomposes and is converted into carbon dioxide (CO), which is then released into the atmosphere. Peat fires cause the same process to occur rapidly and in addition create enormous clouds of smoke that cross international borders, which now happens almost yearly in Southeast Asia. While peatlands constitute only 3% of the world's land area, their degradation produces 7% of all CO emissions.


title: Wetland

text: Many recent studies and reviews have favorably identified the potential for such coastal “blue carbon” ecosystems to provide a natural climate solution in two ways: by conservation, reducing the greenhouse gas emissions arising from the loss and degradation of such habitats, and by restoration, to increase carbon dioxide drawdown and its long-term storage. However, CO removal using coastal blue carbon restoration has questionable cost-effectiveness when considered only as a climate mitigation action, either for carbon-offsetting or for inclusion in Nationally Determined Contributions.


title: Wetland

text: When wetlands are restored they have mitigation effects through their ability to sink carbon, converting a greenhouse gas (carbon dioxide) to solid plant material through the process of photosynthesis, and also through their ability to store and regulate water.


title: Wetland

text: Wetlands store approximately 44.6 million tonnes of carbon per year globally (estimate from 2003). In salt marshes and mangrove swamps in particular, the average carbon sequestration rate is while peatlands sequester approximately .


title: Wetland

text: Coastal wetlands, such as tropical mangroves and some temperate salt marshes, are known to be sinks for carbon that otherwise contribute to climate change in its gaseous forms (carbon dioxide and methane). The ability of many tidal wetlands to store carbon and minimize methane flux from tidal sediments has led to sponsorship of blue carbon initiatives that are intended to enhance those processes.


title: Wetland

text: The restoration of coastal blue carbon ecosystems is highly advantageous for climate change adaptation, coastal protection, food provision and biodiversity conservation.


title: Wetland

text: Since the middle of the 20th century, human-caused climate change has resulted in observable changes in the global water cycle. A warming climate makes extremely wet and very dry occurrences more severe, causing more severe floods and droughts. For this reason, some of the ecosystem services that wetlands provide (e.g. water storage and flood control, groundwater replenishment, shoreline stabilization and storm protection) are important for climate change adaptation measures. In most parts of the world and under all emission scenarios, water cycle variability and accompanying extremes are anticipated to rise more quickly than the changes of average values.


title: Wetland

text: The value of a wetland to local communities typically involves first mapping a region's wetlands, then assessing the functions and ecosystem services the wetlands provide individually and cumulatively, and finally evaluating that information to prioritize or rank individual wetlands or wetland types for conservation, management, restoration, or development. Over the longer term, it requires keeping inventories of known wetlands and monitoring a representative sample of the wetlands to determine changes due to both natural and human factors.


title: Wetland

text: Rapid assessment methods are used to score, rank, rate, or categorize various functions, ecosystem services, species, communities, levels of disturbance, and/or ecological health of a wetland or group of wetlands. This is often done to prioritize particular wetlands for conservation (avoidance) or to determine the degree to which loss or alteration of wetland functions should be compensated, such as by restoring degraded wetlands elsewhere or providing additional protections to existing wetlands. Rapid assessment methods are also applied before and after a wetland has been restored or altered, to help monitor or predict the effects of those actions on various wetland functions and the services they provide. Assessments are typically considered to be "rapid" when they require only a single visit to the wetland lasting less than one day, which in some cases may include interpretation of aerial imagery and geographic information system (GIS) analyses of existing spatial data, but not detailed post-visit laboratory analyses of water or biological samples.


title: Wetland

text: To achieve consistency among persons doing the assessment, rapid methods present indicator variables as questions or checklists on standardized data forms, and most methods standardize the scoring or rating procedure that is used to combine question responses into estimates of the levels of specified functions relative to the levels estimated in other wetlands ("calibration sites") assessed previously in a region. Rapid assessment methods, partly because they often use dozens of indicators pertaining to conditions surrounding a wetland as well as within the wetland itself, aim to provide estimates of wetland functions and services that are more accurate and repeatable than simply describing a wetland's class type. A need for wetland assessments to be rapid arises mostly when government agencies set deadlines for decisions affecting a wetland, or when the number of wetlands needing information on their functions or condition is large.


title: Wetland

text: Although developing a global inventory of wetlands has proven to be a large and difficult undertaking, many efforts at more local scales have been successful. Current efforts are based on available data, but both classification and spatial resolution have sometimes proven to be inadequate for regional or site-specific environmental management decision-making. It is difficult to identify small, long, and narrow wetlands within the landscape. Many of today's remote sensing satellites do not have sufficient spatial and spectral resolution to monitor wetland conditions, although multispectral IKONOS and QuickBird data may offer improved spatial resolutions once it is 4 m or higher. Majority of the pixels are just mixtures of several plant species or vegetation types and are difficult to isolate which translates into an inability to classify the vegetation that defines the wetland.


title: Wetland

text: A wetland needs to be monitored over time to assess whether it is functioning at an ecologically sustainable level or whether it is becoming degraded. Degraded wetlands will suffer a loss in water quality, loss of sensitive species, and aberrant functioning of soil geochemical processes.


title: Wetland

text: Practically, many natural wetlands are difficult to monitor from the ground as they quite often are difficult to access and may require exposure to dangerous plants and animals as well as diseases borne by insects or other invertebrates. Therefore, mapping using aerial imagery is one effective tool to monitor a wetland, especially a large wetland, and can also be used to monitor the status of numerous wetlands throughout a watershed or region. Many remote sensing methods can be used to map wetlands. Remote-sensing technology permits the acquisition of timely digital data on a repetitive basis. This repeat coverage allows wetlands, as well as the adjacent land-cover and land-use types, to be monitored seasonally and/or annually. Using digital data provides a standardized data-collection procedure and an opportunity for data integration within a geographic information system.


title: Wetland

text: Each country and region tends to have its own definition of wetlands for legal purposes. In the United States, wetlands are defined as "those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs and similar areas". This definition has been used in the enforcement of the Clean Water Act. Some US states, such as Massachusetts and New York, have separate definitions that may differ from the federal government's.


title: Wetland

text: In the United States Code, the term wetland is defined "as land that (A) has a predominance of hydric soils, (B) is inundated or saturated by surface or groundwater at a frequency and duration sufficient to support a prevalence of hydrophytic vegetation typically adapted for life in saturated soil conditions and (C) under normal circumstances supports a prevalence of such vegetation." Related to these legal definitions, "normal circumstances" are expected to occur during the wet portion of the growing season under normal climatic conditions (not unusually dry or unusually wet), and in the absence of significant disturbance. It is not uncommon for a wetland to be dry for long portions of the growing season but under normal environmental conditions, the soils will be saturated to the surface or inundated creating anaerobic conditions persisting through the wet portion of the growing season.


title: Wetland

text: The world's largest wetlands include the swamp forests of the Amazon River basin, the peatlands of the West Siberian Plain, the Pantanal in South America, and the Sundarbans in the Ganges-Brahmaputra delta.


title: Scala (programming language)

text: Scala ( ) is a strong statically typed general-purpose programming language which supports both object-oriented programming and functional programming. Designed to be concise, many of Scala's design decisions are aimed to address criticisms of Java.


title: Scala (programming language)

text: Scala source code can be compiled to Java bytecode and run on a Java virtual machine (JVM). Scala can also be compiled to JavaScript to run in a browser, or directly to a native executable. On the JVM Scala provides language interoperability with Java so that libraries written in either language may be referenced directly in Scala or Java code. Like Java, Scala is object-oriented, and uses a syntax termed "curly-brace" which is similar to the language C. Since Scala 3, there is also an option to use the off-side rule (indenting) to structure blocks, and its use is advised. Martin Odersky has said that this turned out to be the most productive change introduced in Scala 3.


title: Scala (programming language)

text: Unlike Java, Scala has many features of functional programming languages (like Scheme, Standard ML, and Haskell), including currying, immutability, lazy evaluation, and pattern matching. It also has an advanced type system supporting algebraic data types, covariance and contravariance, higher-order types (but not higher-rank types), anonymous types, operator overloading, optional parameters, named parameters, raw strings, and an experimental exception-only version of algebraic effects that can be seen as a more powerful version of Java's checked exceptions.


title: Scala (programming language)

text: The name Scala is a portmanteau of "scalable" and "language", signifying that it is designed to grow with the demands of its users.


title: Scala (programming language)

text: The design of Scala started in 2001 at the École Polytechnique Fédérale de Lausanne (EPFL) (in Lausanne, Switzerland) by Martin Odersky. It followed on from work on Funnel, a programming language combining ideas from functional programming and Petri nets. Odersky formerly worked on Generic Java, and javac, Sun's Java compiler.


title: Scala (programming language)

text: After an internal release in late 2003, Scala was released publicly in early 2004 on the Java platform, A second version (v2.0) followed in March 2006.


title: Scala (programming language)

text: On 17 January 2011, the Scala team won a five-year research grant of over €2.3 million from the European Research Council. On 12 May 2011, Odersky and collaborators launched Typesafe Inc. (later renamed Lightbend Inc.), a company to provide commercial support, training, and services for Scala. Typesafe received a $3 million investment in 2011 from Greylock Partners.


title: Scala (programming language)

text: Scala runs on the Java platform (Java virtual machine) and is compatible with existing Java programs. As Android applications are typically written in Java and translated from Java bytecode into Dalvik bytecode (which may be further translated to native machine code during installation) when packaged, Scala's Java compatibility makes it well-suited to Android development, more so when a functional approach is preferred.


title: Scala (programming language)

text: The reference Scala software distribution, including compiler and libraries, is released under the Apache license.


title: Scala (programming language)

text: "Scala.js" is a Scala compiler that compiles to JavaScript, making it possible to write Scala programs that can run in web browsers or Node.js. The compiler, in development since 2013, was announced as no longer experimental in 2015 (v0.6). Version v1.0.0-M1 was released in June 2018 and version 1.1.1 in September 2020.


title: Scala (programming language)

text: Scala Native is a Scala compiler that targets the LLVM compiler infrastructure to create executable code that uses a lightweight managed runtime, which uses the Boehm garbage collector. The project is led by Denys Shabalin and had its first release, 0.1, on 14 March 2017. Development of Scala Native began in 2015 with a goal of being faster than just-in-time compilation for the JVM by eliminating the initial runtime compilation of code and also providing the ability to call native routines directly.


title: Scala (programming language)

text: A reference Scala compiler targeting the .NET Framework and its Common Language Runtime was released in June 2004, but was officially dropped in 2012.


title: Scala (programming language)

text: Unlike the stand-alone Hello World application for Java, there is no class declaration and nothing is declared to be static; a singleton object created with the object keyword is used instead.


title: Scala (programming language)

text: This is analogous to the process for compiling and running Java code. Indeed, Scala's compiling and executing model is identical to that of Java, making it compatible with Java build tools such as Apache Ant.


title: Scala (programming language)

text: Scala includes an interactive shell and scripting support. Saved in a file named codice_1, this can be run as a script using the command:


title: Scala (programming language)

text: The following example shows the differences between Java and Scala syntax. The function mathFunction takes an integer, squares it, and then adds the cube root of that number to the natural log of that number, returning the result (i.e., formula_1):


title: Scala (programming language)

text: The code above shows some of the conceptual differences between Java and Scala's handling of classes:


title: Scala (programming language)

text: Scala has the same compiling model as Java and C#, namely separate compiling and dynamic class loading, so that Scala code can call Java libraries.


title: Scala (programming language)

text: Scala's operational characteristics are the same as Java's. The Scala compiler generates byte code that is nearly identical to that generated by the Java compiler. In fact, Scala code can be decompiled to readable Java code, with the exception of certain constructor operations. To the Java virtual machine (JVM), Scala code and Java code are indistinguishable. The only difference is one extra runtime library, codice_35.


title: Scala (programming language)

text: Scala adds a large number of features compared with Java, and has some fundamental differences in its underlying model of expressions and types, which make the language theoretically cleaner and eliminate several "corner cases" in Java. From the Scala perspective, this is practically important because several added features in Scala are also available in C#.


title: Scala (programming language)

text: As mentioned above, Scala has a good deal of syntactic flexibility, compared with Java. The following are some examples:


title: Scala (programming language)

text: By themselves, these may seem like questionable choices, but collectively they serve the purpose of allowing domain-specific languages to be defined in Scala without needing to extend the compiler. For example, Erlang's special syntax for sending a message to an actor, i.e. codice_67 can be (and is) implemented in a Scala library without needing language extensions.


title: Scala (programming language)

text: Java makes a sharp distinction between primitive types (e.g. codice_68 and codice_69) and reference types (any class). Only reference types are part of the inheritance scheme, deriving from codice_70. In Scala, all types inherit from a top-level class codice_71, whose immediate children are codice_72 (value types, such as codice_73 and codice_74) and codice_75 (reference types, as in Java). This means that the Java distinction between primitive types and boxed types (e.g. codice_68 vs. codice_77) is not present in Scala; boxing and unboxing is completely transparent to the user. Scala 2.10 allows for new value types to be defined by the user.


title: Scala (programming language)

text: Instead of the Java "foreach" loops for looping through an iterator, Scala has codice_78-expressions, which are similar to list comprehensions in languages such as Haskell, or a combination of list comprehensions and generator expressions in Python. For-expressions using the codice_79 keyword allow a new collection to be generated by iterating over an existing one, returning a new collection of the same type. They are translated by the compiler into a series of codice_64, codice_65 and codice_66 calls. Where codice_79 is not used, the code approximates to an imperative-style loop, by translating to codice_84.


title: Scala (programming language)

text: Expression codice_88 is an example of pattern matching (see below). Iterating over a map returns a set of key-value tuples, and pattern-matching allows the tuples to easily be destructured into separate variables for the key and value. Similarly, the result of the comprehension also returns key-value tuples, which are automatically built back up into a map because the source object (from the variable codice_89) is a map. Note that if codice_89 instead held a list, set, array or other collection of tuples, exactly the same code above would yield a new collection of the same type.


title: Scala (programming language)

text: While supporting all of the object-oriented features available in Java (and in fact, augmenting them in various ways), Scala also provides a large number of capabilities that are normally found only in functional programming languages. Together, these features allow Scala programs to be written in an almost completely functional style and also allow functional and object-oriented styles to be mixed.


title: Scala (programming language)

text: Unlike C or Java, but similar to languages such as Lisp, Scala makes no distinction between statements and expressions. All statements are in fact expressions that evaluate to some value. Functions that would be declared as returning codice_24 in C or Java, and statements like codice_92 that logically do not return a value, are in Scala considered to return the type codice_25, which is a singleton type, with only one object of that type. Functions and operators that never return at all (e.g. the codice_94 operator or a function that always exits non-locally using an exception) logically have return type codice_95, a special type containing no objects; that is, a bottom type, i.e. a subclass of every possible type. (This in turn makes type codice_95 compatible with every type, allowing type inference to function correctly.)


title: Scala (programming language)

text: Similarly, an codice_97 "statement" is actually an expression, which produces a value, i.e. the result of evaluating one of the two branches. This means that such a block of code can be inserted wherever an expression is desired, obviating the need for a ternary operator in Scala:


title: Scala (programming language)

text: For similar reasons, codice_7 statements are unnecessary in Scala, and in fact are discouraged. As in Lisp, the last expression in a block of code is the value of that block of code, and if the block of code is the body of a function, it will be returned by the function.


title: Scala (programming language)

text: To make it clear that all functions are expressions, even methods that return codice_25 are written with an equals sign


title: Scala (programming language)

text: Due to type inference, the type of variables, function return values, and many other expressions can typically be omitted, as the compiler can deduce it. Examples are codice_100 (for an immutable constant or immutable object) or codice_101 (for a variable whose value can later be changed). Type inference in Scala is essentially local, in contrast to the more global Hindley-Milner algorithm used in Haskell, ML and other more purely functional languages. This is done to facilitate object-oriented programming. The result is that certain types still need to be declared (most notably, function parameters, and the return types of recursive functions), e.g.


title: Scala (programming language)

text: In Scala, functions are objects, and a convenient syntax exists for specifying anonymous functions. An example is the expression codice_102, which specifies a function with one parameter, that compares its argument to see if it is less than 2. It is equivalent to the Lisp form codice_103. Note that neither the type of codice_104 nor the return type need be explicitly specified, and can generally be inferred by type inference; but they can be explicitly specified, e.g. as codice_105 or even codice_106.


title: Scala (programming language)

text: Anonymous functions behave as true closures in that they automatically capture any variables that are lexically available in the environment of the enclosing function. Those variables will be available even after the enclosing function returns, and unlike in the case of Java's "anonymous inner classes" do not need to be declared as final. (It is even possible to modify such variables if they are mutable, and the modified value will be available the next time the anonymous function is called.)


title: Scala (programming language)

text: Scala enforces a distinction between immutable and mutable variables. Mutable variables are declared using the codice_6 keyword and immutable values are declared using the codice_5 keyword.


title: Scala (programming language)

text: A variable declared using the codice_5 keyword cannot be reassigned in the same way that a variable declared using the codice_113 keyword can't be reassigned in Java. codice_5s are only shallowly immutable, that is, an object referenced by a val is not guaranteed to itself be immutable.


title: Scala (programming language)

text: Immutable classes are encouraged by convention however, and the Scala standard library provides a rich set of immutable collection classes.


title: Scala (programming language)

text: Scala provides mutable and immutable variants of most collection classes, and the immutable version is always used unless the mutable version is explicitly imported.


title: Scala (programming language)

text: The immutable variants are persistent data structures that always return an updated copy of an old object instead of updating the old object destructively in place.


title: Scala (programming language)

text: An example of this is immutable linked lists where prepending an element to a list is done by returning a new list node consisting of the element and a reference to the list tail.


title: Scala (programming language)

text: Appending an element to a list can only be done by prepending all elements in the old list to a new list with only the new element.


title: Scala (programming language)

text: In the same way, inserting an element in the middle of a list will copy the first half of the list, but keep a reference to the second half of the list. This is called structural sharing.


title: Scala (programming language)

text: Evaluation is strict ("eager") by default. In other words, Scala evaluates expressions as soon as they are available, rather than as needed. However, it is possible to declare a variable non-strict ("lazy") with the codice_115 keyword, meaning that the code to produce the variable's value will not be evaluated until the first time the variable is referenced. Non-strict collections of various types also exist (such as the type codice_116, a non-strict linked list), and any collection can be made non-strict with the codice_117 method. Non-strict collections provide a good semantic fit to things like server-produced data, where the evaluation of the code to generate later elements of a list (that in turn triggers a request to a server, possibly located somewhere else on the web) only happens when the elements are actually needed.


title: Scala (programming language)

text: Functional programming languages commonly provide tail call optimization to allow for extensive use of recursion without stack overflow problems. Limitations in Java bytecode complicate tail call optimization on the JVM. In general, a function that calls itself with a tail call can be optimized, but mutually recursive functions cannot. Trampolines have been suggested as a workaround. Trampoline support has been provided by the Scala library with the object codice_118 since Scala 2.8.0 (released 14 July 2010). A function may optionally be annotated with codice_119, in which case it will not compile unless it is tail recursive.


title: Scala (programming language)

text: Scala has built-in support for pattern matching, which can be thought of as a more sophisticated, extensible version of a switch statement, where arbitrary data types can be matched (rather than just simple types like integers, booleans and strings), including arbitrary nesting. A special type of class known as a "case class" is provided, which includes automatic support for pattern matching and can be used to model the algebraic data types used in many functional programming languages. (From the perspective of Scala, a case class is simply a normal class for which the compiler automatically adds certain behaviors that could also be provided manually, e.g., definitions of methods providing for deep comparisons and hashing, and destructuring a case class on its constructor parameters during pattern matching.)


title: Scala (programming language)

text: The idea here is that we partition a list into the elements less than a pivot and the elements not less, recursively sort each part, and paste the results together with the pivot in between. This uses the same divide-and-conquer strategy of mergesort and other fast sorting algorithms.


title: Scala (programming language)

text: The codice_120 operator is used to do pattern matching on the object stored in codice_121. Each codice_122 expression is tried in turn to see if it will match, and the first match determines the result. In this case, codice_123 only matches the literal object codice_123, but codice_125 matches a non-empty list, and simultaneously "destructures" the list according to the pattern given. In this case, the associated code will have access to a local variable named codice_126 holding the head of the list, and another variable codice_127 holding the tail of the list. Note that these variables are read-only, and are semantically very similar to variable bindings established using the codice_128 operator in Lisp and Scheme.


title: Scala (programming language)

text: Pattern matching also happens in local variable declarations. In this case, the return value of the call to codice_129 is a tuple — in this case, two lists. (Tuples differ from other types of containers, e.g. lists, in that they are always of fixed size and the elements can be of differing types — although here they are both the same.) Pattern matching is the easiest way of fetching the two parts of the tuple.


title: Scala (programming language)

text: The form codice_130 is a declaration of an anonymous function with a placeholder variable; see the section above on anonymous functions.


title: Scala (programming language)

text: The list operators codice_131 (which adds an element onto the beginning of a list, similar to codice_132 in Lisp and Scheme) and codice_133 (which appends two lists together, similar to codice_134 in Lisp and Scheme) both appear. Despite appearances, there is nothing "built-in" about either of these operators. As specified above, any string of symbols can serve as function name, and a method applied to an object can be written "infix"-style without the period or parentheses. The line above as written:


title: Scala (programming language)

text: in more standard method-call notation. (Methods that end with a colon are right-associative and bind to the object to the right.)


title: Scala (programming language)

text: In the pattern-matching example above, the body of the codice_120 operator is a partial function, which consists of a series of codice_122 expressions, with the first matching expression prevailing, similar to the body of a switch statement. Partial functions are also used in the exception-handling portion of a codice_139 statement:


title: Scala (programming language)

text: Finally, a partial function can be used alone, and the result of calling it is equivalent to doing a codice_120 over it. For example, the prior code for quicksort can be written thus:


title: Scala (programming language)

text: Here a read-only "variable" is declared whose type is a function from lists of integers to lists of integers, and bind it to a partial function. (Note that the single parameter of the partial function is never explicitly declared or named.) However, we can still call this variable exactly as if it were a normal function:


title: Scala (programming language)

text: Scala is a pure object-oriented language in the sense that every value is an object. Data types and behaviors of objects are described by classes and traits. Class abstractions are extended by subclassing and by a flexible mixin-based composition mechanism to avoid the problems of multiple inheritance.


title: Scala (programming language)

text: Traits are Scala's replacement for Java's interfaces. Interfaces in Java versions under 8 are highly restricted, able only to contain abstract function declarations. This has led to criticism that providing convenience methods in interfaces is awkward (the same methods must be reimplemented in every implementation), and extending a published interface in a backwards-compatible way is impossible. Traits are similar to mixin classes in that they have nearly all the power of a regular abstract class, lacking only class parameters (Scala's equivalent to Java's constructor parameters), since traits are always mixed in with a class. The codice_141 operator behaves specially in traits, allowing traits to be chained using composition in addition to inheritance. The following example is a simple window system:


title: Scala (programming language)

text: val mywin = new SimpleWindow with VerticalScrollbarDecoration with HorizontalScrollbarDecoration with TitleDecoration