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62-581: Tanjong Chek Jawa (or Tanjung Chek Jawa or simply Chek Jawa ) is a cape and the name of its 100-hectare wetlands located on the south-eastern tip of Pulau Ubin , an island off the north-eastern coast of the main island of Singapore . Chek Jawa is among the last few places left in Singapore with a natural rocky shore. The wetlands are unique as several ecosystems can be observed in one area – sandy beach, rocky beach, seagrass lagoon, coral rubble, mangroves and coastal forest. The site forms part of

124-711: A sink or a source of carbon, depending on the specific wetland. If they function as a carbon sink, they can help with climate change mitigation . However, wetlands can also be a significant source of methane emissions due to anaerobic decomposition of soaked detritus , and some are also emitters of nitrous oxide . Humans are disturbing and damaging wetlands in many ways, including oil and gas extraction , building infrastructure, overgrazing of livestock , overfishing , alteration of wetlands including dredging and draining, nutrient pollution , and water pollution . Wetlands are more threatened by environmental degradation than any other ecosystem on Earth, according to

186-607: A dense canopy that blocks light from lower growing plants. Early observations of canopies were made from the ground using binoculars or by examining fallen material. Researchers would sometimes erroneously rely on extrapolation by using more reachable samples taken from the understory . In some cases, they would use unconventional methods such as chairs suspended on vines or hot-air dirigibles, among others. Modern technology, including adapted mountaineering gear, has made canopy observation significantly easier and more accurate, allowed for longer and more collaborative work, and broadened

248-549: A few feet. Dominant and co-dominant canopy trees form the uneven canopy layer. Canopy trees are able to photosynthesize relatively rapidly with abundant light, so it supports the majority of primary productivity in forests. The canopy layer provides protection from strong winds and storms while also intercepting sunlight and precipitation, leading to a relatively sparsely vegetated understory layer. Forest canopies are home to unique flora and fauna not found in other layers of forests. The highest terrestrial biodiversity resides in

310-402: 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.' For each of these definitions and others, regardless of the purpose, hydrology is emphasized (shallow waters, water-logged soils). The soil characteristics and

372-1248: A polar climate, wetland temperatures can be as low as −50 °C (−58 °F). Peatlands in arctic and subarctic regions insulate the permafrost , thus delaying or preventing its thawing during summer, as well as inducing its formation. The amount of precipitation a wetland receives varies widely according to its area. Wetlands in Wales , Scotland , and western Ireland typically receive about 1,500 mm (59 in) per year. In some places in Southeast Asia , where heavy rains occur, they can receive up to 10,000 mm (390 in). In some drier regions, wetlands exist where as little as 180 mm (7.1 in) precipitation occurs each year. Temporal variation: Surface flow may occur in some segments, with subsurface flow in other segments. 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. The most important factor producing wetlands

434-540: 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

496-399: 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. Canopy (forest) In biology , the canopy is

558-454: A role in modifying the internal environment of the forest by acting as a buffer for incoming light, wind, and temperature fluctuations. The forest canopy layer supports a diverse range of flora and fauna. It has been dubbed "the last biotic frontier" as it provides a habitat that has allowed for the evolution of countless species of plants, microorganisms, invertebrates (e.g., insects), and vertebrates (e.g., birds and mammals) that are unique to

620-422: 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. Carbon is the major nutrient cycled within wetlands. Most nutrients, such as sulfur , phosphorus , carbon , and nitrogen are found within

682-410: 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. Variations of names for wetland systems: 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

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744-406: A visitor management plan for Chek Jawa, at a cost of S$ 7 million. These included a 1.1-kilometre boardwalk , a 20-metre tall viewing tower and a visitor centre with a viewing jetty . The new boardwalk running along the coast and into the mangrove area allows visitors to get up close to plant and marine life such as fiddler crabs and monitor lizards , without damaging the area. Special care

806-508: 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". 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

868-422: A wetland system includes its plants ( flora ) and animals ( fauna ) and microbes (bacteria, fungi). The most important factor is the wetland's 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

930-403: A wetland) affects hydro-periods (temporal fluctuations in water levels) by controlling the water balance and water storage within a wetland. Landscape characteristics control wetland hydrology and water chemistry. The O 2 and CO 2 concentrations of water depend upon temperature , atmospheric pressure and mixing with the air (from winds or water flows). Water chemistry within wetlands

992-558: A whole. 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. Floodplains and closed-depression wetlands can provide the functions of storage reservoirs and flood protection. 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

1054-577: 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 does not 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,

1116-440: 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. Because bogs receive most of their water from precipitation and humidity from

1178-629: Is either freshwater , brackish or saltwater . The main types of wetland are defined based on the dominant plants and the source of the water. For example, marshes are wetlands dominated by emergent herbaceous vegetation such as reeds , cattails and sedges . Swamps are dominated by woody vegetation such as trees and shrubs (although reed swamps in Europe are dominated by reeds, not trees). Mangrove forest are wetlands with mangroves , halophytic woody plants that have evolved to tolerate salty water . Examples of wetlands classified by

1240-412: 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. Wetland hydrology is associated with

1302-451: Is the only place in the world where both crocodiles and alligators coexist. The saltwater crocodile inhabits estuaries and mangroves. Snapping turtles also inhabit wetlands. Birds , particularly waterfowl and waders use wetlands extensively. 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

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1364-545: 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

1426-492: The Millennium Ecosystem Assessment from 2005. Methods exist for assessing wetland ecological health . These methods have contributed to wetland conservation by raising public awareness of the functions that wetlands can provide. Since 1971, work under an international treaty seeks to identify and protect " wetlands of international importance ." A simplified definition of wetland is "an area of land that

1488-666: The Pantanal in South America, and the Sundarbans in the Ganges - Brahmaputra delta. Wetlands contribute many ecosystem services that benefit people. These include for example water purification , stabilization of shorelines, storm protection and flood control . In addition, wetlands also process and condense carbon (in processes called carbon fixation and sequestration ), and other nutrients and water pollutants . Wetlands can act as

1550-580: The Ubin–Khatib Important Bird Area (IBA), identified as such by BirdLife International because it supports significant numbers of visiting and resident birds, some of which are threatened . In December 2001, the government called off reclamation plans of the Chek Jawa area after a biodiversity survey conducted by conservationist volunteers. State use of the land will be deferred for the next 10 years. However, Chek Jawa may still be re-used by

1612-444: 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. 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 . Salinity has

1674-576: The beavers , coypu , swamp rabbit , Florida panther , jaguar , 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. Invertebrates of wetlands include aquatic insects such as dragonflies , aquatic bugs and beetles , midges, mosquitos , crustaceans such as crabs, crayfish, shrimps, microcrustaceans, mollusks like clams, mussels, snails and worms. Invertebrates comprise more than half of

1736-619: The Okavango River inland delta, the Kafue River flood plain, the Lake Bangweulu flood plain (Africa), Mississippi River (US), Amazon River (South America), Yangtze River (China), Danube River (Central Europe) and Murray-Darling River (Australia). Groundwater replenishment can be achieved for example by marsh , swamp , and subterranean karst and cave hydrological systems. The surface water visibly seen in wetlands only represents

1798-511: The Southeastern US, mallines of Argentina, Mediterranean seasonal ponds of Europe and California, turloughs of Ireland, billabongs of Australia, among many others. 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

1860-494: 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). Peatlands are

1922-610: The United States' commercial fish and shellfish stocks depend solely on estuaries to survive. 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

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1984-475: The aboveground portion of a plant cropping or crop , formed by the collection of individual plant crowns . In forest ecology , the canopy is the upper layer or habitat zone, formed by mature tree crowns and including other biological organisms ( epiphytes , lianas , arboreal animals , etc..). The communities that inhabit the canopy layer are thought to be involved in maintaining forest diversity, resilience , and functioning. Shade trees normally have

2046-555: The area. In 2001, the National Parks Board (NParks) took over Chek Jawa's management. NParks conducts free guided tours of Chek Jawa a few times each month during low spring tide periods, and about 20,000 visitors have gone on its tours from 2002 to 2007. In early 2007, Chek Jawa was closed to the public after being damaged by heavy rains in December 2006. Freshwater rains upset the wetlands' saltwater balance, resulting in

2108-479: The canopies of tropical rainforests . Many rainforest animals have evolved to live solely in the canopy and never touch the ground. The canopy of a rainforest is typically about 10 m thick, and intercepts around 95% of sunlight. The canopy is below the emergent layer , a sparse layer of very tall trees, typically one or two per hectare. With an abundance of water and a near ideal temperature in rainforests, light and nutrients are two factors that limit tree growth from

2170-409: The canopy and subtract throughfall and stem flow ). However, the problem with this method is that the canopy is not homogeneous, which causes difficulty in obtaining representative throughfall data. A method employed to avoid this problem is covering forest floor with plastic sheets and collecting the throughfall. The disadvantage of this method is that it is not suitable for long periods, because in

2232-458: The coral rubble. Within each of the ecosystems, there is an abundance of natural creatures, rare plants, local and migratory birds. These have attracted photographers, nature lovers, student groups and others to visit Chek Jawa. 01°24′29.06″N 103°59′32.28″E  /  1.4080722°N 103.9923000°E  / 1.4080722; 103.9923000 Wetland Wetlands exist on every continent , except Antarctica . The water in wetlands

2294-482: The effects of precipitation on the local climate. Forest canopies also buffer the effects of temperature within forests by creating vertical light gradients. Variations in forest microclimate are also driven by the structure and physiology of canopy trees and epiphytes. This produces feedback loops where the species identity, growth traits, and forest stand composition of canopy trees determine forest microclimate. Forest canopies are significantly involved in maintaining

2356-622: 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 11 °C (52 °F). 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 50 °C (122 °F) and these habitats would therefore be subject to rapid evaporation. In northeastern Siberia , which has

2418-494: The following areas: According to the Ramsar Convention: 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

2480-401: The government in and after 2012. Previously virtually unknown, Chek Jawa came into national prominence and focus only since the early 2000s when the area's rich biodiversity was discovered almost by chance during a nature outing at low tide . News on the impending land reclamation works planned by the government on the area sparked a rare show of public-led and coordinated effort to reverse

2542-412: The greenhouse effect, thereby causing the planet to become warmer. Canopy interception is the rainfall that is intercepted by the canopy of a tree and successively evaporates from the leaves. Precipitation that is not intercepted will fall as throughfall or stemflow on the forest floor. Many methods exist to measure canopy interception. The most often used method is by measuring rainfall above

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2604-464: The interface between truly terrestrial ecosystems and aquatic systems, making them inherently different from each other, yet highly dependent on both." In environmental decision-making, there are subsets of definitions that are agreed upon to make regulatory and policy decisions. Under the Ramsar international wetland conservation treaty , wetlands are defined as follows: An ecological definition of

2666-462: The known animal species in wetlands, and are considered the primary food web link between plants and higher animals (such as fish and birds). 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

2728-452: The natural habitat. The Singapore Government , in turn, surprised many when they acceded to these requests in December 2001. They agreed to leave the Chek Jawa area untouched for the next ten years. The area has been fenced off due to an increase of tourists into the area, damaging the ecosystem in the area. Conservation efforts were made by the Ministry of National Development to preserve

2790-832: The plants and animals controlled by the wetland hydrology are often additional components of the definitions. Wetlands can be tidal (inundated by tides) or non-tidal. The water in wetlands is either freshwater , brackish , saline , or alkaline . 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. 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

2852-463: The reclamation plans. A group of volunteers, headed by botanist Joseph Lai (who first discovered Chek Jawa's rich ecosystems in December 2000), conducted a biodiversity survey months before the area was to be reclaimed in 2001. This survey was captured on the documentary Remember Chek Jawa by Eric Lin Youwei. The volunteers then submitted a report and petitioned to the government for the preservation of

2914-582: The scope of canopy study. Canopy structure is the organization or spatial arrangement (three-dimensional geometry) of a plant canopy. Leaf area index , leaf area per unit ground area, is a key measure used to understand and compare plant canopies. The canopy is taller than the understory layer. The canopy holds 90% of the animals in the rainforest. Canopies can cover vast distances and appear to be unbroken when observed from an airplane. However, despite overlapping tree branches, rainforest canopy trees rarely touch each other. Rather, they are usually separated by

2976-429: 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. Mangroves , coral reefs , salt marsh can help with shoreline stabilization and storm protection. Tidal and inter-tidal wetland systems protect and stabilize coastal zones. Coral reefs provide

3038-537: 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. The life forms of

3100-412: The soils and plants at higher elevations. Plants and animals may vary within a wetland seasonally or in response to flood regimes. There are four main groups of hydrophytes that are found in wetland systems throughout the world. 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

3162-515: The sources of water include tidal wetlands , where the water source is ocean tides ); estuaries , water source is mixed tidal and river waters; floodplains , water source is excess water from overflowed rivers or lakes; and bogs and vernal ponds , water source is rainfall or meltwater . The world's largest wetlands include the Amazon River basin , the West Siberian Plain ,

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3224-406: 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

3286-446: The stability of the global climate. They are responsible for at least half of the global carbon dioxide exchange between terrestrial ecosystems and the atmosphere. Forest canopies act as carbon sinks, reducing the increase of atmospheric CO 2 caused by human activity. The destruction of forest canopies would lead to the release of carbon dioxide, resulting in an increased concentration of atmospheric CO 2 . This would then contribute to

3348-709: The surface of the water. 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. Many species of fish are highly dependent on wetland ecosystems. Seventy-five percent of

3410-490: The surface. Submerged species provide a food source for native fauna, habitat for invertebrates, and also possess filtration capabilities. Examples include seagrasses and eelgrass . Floating water plants or floating vegetation are usually small, like those in the Lemnoideae subfamily (duckweeds). Emergent vegetation like the cattails ( Typha spp.), sedges ( Carex spp.) and arrow arum ( Peltandra virginica ) rise above

3472-457: The surrounding environment resulting in increased extinction rates in unfavorable and polluted environmental conditions. 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

3534-440: 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 . A more concise definition is a community composed of hydric soil and hydrophytes . Wetlands have also been described as ecotones , providing a transition between dry land and water bodies. Wetlands exist "...at

3596-443: The understory to the canopy. In the permaculture and forest gardening community, the canopy is the highest of seven layers. Forest canopies have unique structural and ecological complexities and are important for the forest ecosystem. They are involved in critical functions such as rainfall interception, light absorption, nutrient and energy cycling, gas exchange, and providing habitat for diverse wildlife. The canopy also plays

3658-492: The upper layer of forests. Forest canopies are arguably considered some of the most species-rich environments on the planet. It is believed that the communities found within the canopy layer play an essential role in the functioning of the forest, as well as maintaining diversity and ecological resilience . Forest canopies contribute to forest microclimate by controlling and buffering variations in climatic conditions. Forest canopies intercept rain and snowfall, thereby buffering

3720-427: The visitor center, which was converted from a Tudor-style house built in the 1930s, visitors can learn more about Chek Jawa's wildlife. A small trash receptacle and a soda vending machine are available, otherwise the small kiosk style center is typically unmanned. Chek Jawa is made up of 6 interdependent ecosystems – namely, its coastal forest, mangrove forest , its rocky shore , the sandy shore, seagrass lagoon and

3782-554: The widespread death of marine creatures such as sea anemones , seastars , sponges . Tours conducted by NParks were stopped in March that year to let the wetlands recover. Source: On 8 July that year, the nature preserve was re-opened to the public and is free of charge. Visitors going to Chek Jawa no longer need to join the free guided tours conducted by NParks. These are conducted only a few times each month during low spring tide periods. The Singapore Government added new amenities with

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3844-462: Was taken to construct the boardwalk, which is made from concrete but simulated to resemble timber. This is more environmentally friendly as it cuts down on the use of wood while still retaining its natural feel. The free seven-story viewing tower called the Jejawi Tower allows visitors to view the tree canopy and observe birdlife such as the collared kingfisher and straw-headed bulbul . At

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