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78-592: The Ord River floodplain is the floodplain of the lower Ord River in the Shire of Wyndham-East Kimberley , in the Kimberley region of northern Western Australia . It lies within the Victoria Bonaparte IBRA bioregion and contains river, seasonal creek, tidal mudflat and floodplain wetlands, with extensive stands of mangroves , that support saltwater crocodiles and many waterbirds . It

156-530: A closed and continuous tree canopy , moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropical rainforests or temperate rainforests , but other types have been described. Estimates vary from 40% to 75% of all biotic species being indigenous to the rainforests. There may be many millions of species of plants, insects and microorganisms still undiscovered in tropical rainforests. Tropical rainforests have been called

234-554: A flood-prone property to qualify for government-subsidized insurance, a local community must adopt an ordinance that protects the floodway and requires that new residential structures built in Special Flood Hazard Areas be elevated to at least the level of the 100-year flood. Commercial structures can be elevated or floodproofed to or above this level. In some areas without detailed study information, structures may be required to be elevated to at least two feet above

312-445: A floodplain. The quantity of sediments in a floodplain greatly exceeds the river load of sediments. Thus, floodplains are an important storage site for sediments during their transport from where they are generated to their ultimate depositional environment. When the rate at which the river is cutting downwards becomes great enough that overbank flows become infrequent, the river is said to have abandoned its floodplain. Portions of

390-629: A large loss of Amazonian rainforest around 2050 due to drought , forest dieback and the subsequent release of more carbon dioxide. Tropical rainforests provide timber as well as animal products such as meat and hides. Rainforests also have value as tourism destinations and for the ecosystem services provided. Many foods originally came from tropical forests, and are still mostly grown on plantations in regions that were formerly primary forest. Also, plant-derived medicines are commonly used for fever, fungal infections, burns, gastrointestinal problems, pain, respiratory problems, and wound treatment. At

468-567: A little fresh water from small and ephemeral creeks. The site has a dry tropical climate. Rainfall is monsoonal , with the hot and humid wet season occurring from November to March. Wyndham has an average annual rainfall of 695 millimetres (27.4 in). The dry season is mild, with periods of steady south-easterly winds. The average maximum temperature varies from 30 °C (86 °F) in July to 39 °C (102 °F) in December. Within

546-490: A moist layer of leaf litter, the presence of epiphytes and lianas and the absence of wildfire. The largest areas of rainforest are tropical or temperate rainforests, but other vegetation associations including subtropical rainforest , littoral rainforest , cloud forest , vine thicket and even dry rainforest have been described. Tropical rainforests are characterized by a warm and wet climate with no substantial dry season: typically found within 10 degrees north and south of

624-423: A more open canopy layer than other rainforests, and are found in areas of lower rainfall (630–1,100 mm (25–43 in)). They generally have two layers of trees. A tropical rainforest typically has a number of layers, each with different plants and animals adapted for life in that particular area. Examples include the emergent, canopy , understory and forest floor layers. The emergent layer contains

702-513: A small net impact on atmospheric carbon dioxide levels, though they may have other climatic effects (on cloud formation, for example, by recycling water vapour ). No rainforest today can be considered to be undisturbed. Human-induced deforestation plays a significant role in causing rainforests to release carbon dioxide, as do other factors, whether human-induced or natural, which result in tree death, such as burning and drought. Some climate models operating with interactive vegetation predict

780-407: A small number of very large trees called emergents , which grow above the general canopy , reaching heights of 45–55 m, although on occasion a few species will grow to 70–80 m tall. They need to be able to withstand the hot temperatures and strong winds that occur above the canopy in some areas. Eagles , butterflies , bats and certain monkeys inhabit this layer. The canopy layer contains

858-828: A study by Colin Turnbull , The Forest People , in 1962. Pygmies who live in Southeast Asia are, amongst others, referred to as " Negrito ". There are many tribes in the rainforests of the Malaysian state of Sarawak. Sarawak is part of Borneo, the third largest island in the world. Some of the other tribes in Sarawak are: the Kayan, Kenyah, Kejaman, Kelabit, Punan Bah, Tanjong, Sekapan, and the Lahanan. Collectively, they are referred to as Dayaks or Orangulu which means "people of

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936-437: A trend towards declining populations in rainforests, for example, reptiles that feed on amphibians and reptiles. This trend requires close monitoring. The seasonality of rainforests affects the reproductive patterns of amphibians, and this in turn can directly affect the species of reptiles that feed on these groups, particularly species with specialized feeding, since these are less likely to use alternative resources. Despite

1014-436: A very broad array of fauna , including mammals , reptiles , amphibians , birds and invertebrates . Mammals may include primates , felids and other families. Reptiles include snakes , turtles , chameleons and other families; while birds include such families as vangidae and Cuculidae . Dozens of families of invertebrates are found in rainforests. Fungi are also very common in rainforest areas as they can feed on

1092-405: A woodland 10 metres (33 ft) high, are Bruguiera parviflora , Avicennia marina and Aegiceras corniculatum , and then a belt of Rhizophora stylosa 12–15 metres (39–49 ft) high. On the landward edge is a 4 metres (13 ft) high thicket of Avicennia marina , Ceriops tagal and Aegialitis annulata . Sporobolus virginicus grassland and samphire grow on the mudflats behind

1170-546: Is a problem in freshwater systems. Much of the phosphorus in freshwater systems comes from municipal wastewater treatment plants and agricultural runoff. Stream connectivity controls whether phosphorus cycling is mediated by floodplain sediments or by external processes. Under conditions of stream connectivity, phosphorus is better able to be cycled, and sediments and nutrients are more readily retained. Water in freshwater streams ends up in either short-term storage in plants or algae or long-term in sediments. Wet/dry cycling within

1248-503: Is abundant. Many seedlings that will grow to the canopy level are present in the understory. Only about 5% of the sunlight shining on the rainforest canopy reaches the understory. This layer can be called a shrub layer , although the shrub layer may also be considered a separate layer. The forest floor , the bottom-most layer, receives only 2% of the sunlight. Only plants adapted to low light can grow in this region. Away from riverbanks , swamps and clearings, where dense undergrowth

1326-406: Is advantageous for the rapid colonization of large areas of the floodplain. This allows them to take advantage of shifting floodplain geometry. For example, floodplain trees are fast-growing and tolerant of root disturbance. Opportunists (such as birds) are attracted to the rich food supply provided by the flood pulse. Floodplain ecosystems have distinct biozones. In Europe, as one moves away from

1404-498: Is any area subject to inundation by a 100-year flood. A problem is that any alteration of the watershed upstream of the point in question can potentially affect the ability of the watershed to handle water, and thus potentially affects the levels of the periodic floods. A large shopping center and parking lot, for example, may raise the levels of 5-year, 100-year, and other floods, but the maps are rarely adjusted and are frequently rendered obsolete by subsequent development. In order for

1482-460: Is described as vertical accretion , since the deposits build upwards. In undisturbed river systems, overbank flow is frequent, typically occurring every one to two years, regardless of climate or topography. Sedimentation rates for a three-day flood of the Meuse and Rhine Rivers in 1993 found average sedimentation rates in the floodplain of between 0.57 and 1.0 kg/m . Higher rates were found on

1560-419: Is found, the forest floor is relatively clear of vegetation because of the low sunlight penetration. It also contains decaying plant and animal matter, which disappears quickly, because the warm, humid conditions promote rapid decay. Many forms of fungi growing here help decay the animal and plant waste. More than half of the world's species of plants and animals are found in rainforests. Rainforests support

1638-632: Is freshwater, while the northern, or downstream part, is either regularly flooded with saltwater or contains saline soils. The lower reaches of the Ord River extend from the Parry Creek floodplain northwards to the Cambridge Gulf . The upper reaches of the Ord River are permanently fresh; the lower reaches, when not in flood, become saline due to the tidal cycle which, at the coast, has an amplitude of up to 8 metres (26 ft). Within

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1716-565: Is largely a result of flood control, hydroelectric development (such as reservoirs), and conversion of floodplains to agriculture use. Transportation and waste disposal also have detrimental effects. The result is the fragmentation of these ecosystems, resulting in loss of populations and diversity and endangering the remaining fragments of the ecosystem. Flood control creates a sharper boundary between water and land than in undisturbed floodplains, reducing physical diversity. Floodplain forests protect waterways from erosion and pollution and reduce

1794-402: Is most common in sections of rivers where the river bed is accumulating sediments ( aggrading ). Repeated flooding eventually builds up an alluvial ridge, whose natural levees and abandoned meander loops may stand well above most of the floodplain. The alluvial ridge is topped by a channel belt formed by successive generations of channel migration and meander cutoff. At much longer intervals,

1872-589: Is recognised as an internationally important wetland area, with 1,384 square kilometres (534 sq mi) of it designated on 7 June 1990 as Ramsar Site 477 under the Ramsar Convention on Wetlands. The site lies about 8 kilometres (5.0 mi) east of the town of Wyndham , extending from 14°51′S 128°12′E  /  14.850°S 128.200°E  / -14.850; 128.200 to 15°46′S 128°33′E  /  15.767°S 128.550°E  / -15.767; 128.550 . It comprises

1950-465: The Amazon rainforest ), Central America (e.g. Bosawás , the southern Yucatán Peninsula - El Peten - Belize - Calakmul ), Australia , and on Pacific Islands (such as Hawaiʻi ). Tropical forests have been called the "Earth's lungs ", although it is now known that rainforests contribute little net oxygen addition to the atmosphere through photosynthesis . Tropical forests cover a large part of

2028-878: The Intertropical Convergence Zone . The broader category of tropical moist forests are located in the equatorial zone between the Tropic of Cancer and Tropic of Capricorn . Tropical rainforests exist in Southeast Asia (from Myanmar (Burma) ) to the Philippines , Malaysia , Indonesia , Papua New Guinea and Sri Lanka ; also in Sub-Saharan Africa from the Cameroon to the Congo ( Congo Rainforest ), South America (e.g.

2106-557: The Yellow River in China – see list of deadliest floods . The worst of these, and the worst natural disaster (excluding famine and epidemics), was the 1931 China floods , estimated to have killed millions. This had been preceded by the 1887 Yellow River flood , which killed around one million people and is the second-worst natural disaster in history. The extent of floodplain inundation depends partly on flood magnitude, defined by

2184-418: The equator . Mean monthly temperatures exceed 18 °C (64 °F) during all months of the year. Average annual rainfall is no less than 168 cm (66 in) and can exceed 1,000 cm (390 in) although it typically lies between 175 cm (69 in) and 200 cm (79 in). Many of the world's tropical forests are associated with the location of the monsoon trough , also known as

2262-747: The return period . In the United States, the Federal Emergency Management Agency (FEMA) manages the National Flood Insurance Program (NFIP). The NFIP offers insurance to properties located within a flood-prone area, as defined by the Flood Insurance Rate Map (FIRM), which depicts various flood risks for a community. The FIRM typically focuses on the delineation of the 100-year flood inundation area, also known within

2340-492: The "jewels of the Earth" and the " world's largest pharmacy ", because over one quarter of natural medicines have been discovered there. Rainforests as well as endemic rainforest species are rapidly disappearing due to deforestation , the resulting habitat loss and pollution of the atmosphere . Rainforests are characterized by a closed and continuous tree canopy, high humidity, the presence of moisture-dependent vegetation,

2418-467: The 13 species of terrestrial bird restricted to such habitat, or to rainforest, in Western Australia, including the black butcherbird . About 200 bird species have been recorded from the site. The lower Ord River contains a high density of salt water crocodiles. The mangroves support at least six species of microbat , the black flying-fox and grassland melomys . Other mammals known from

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2496-400: The 20th century and the area covered by rainforests around the world is shrinking. Biologists have estimated that large numbers of species are being driven to extinction (possibly more than 50,000 a year; at that rate, says E. O. Wilson of Harvard University , a quarter or more of all species on Earth could be exterminated within 50 years) due to the removal of habitat with destruction of

2574-526: The Cambridge Gulf is one of the richest places for mangroves in the Kimberley region in terms of species diversity, structural complexity, and area, with 14 species occurring within the site. Zonation is evident; mangrove species in the seaward zone form a woodland about 8 metres (26 ft) high, dominated by Sonneratia alba , Avicennia marina and Aegiceras corniculatum . Behind this, in

2652-417: The Earth, but one to two hundred feet above it, extending over thousands of square miles." A true exploration of this habitat only began in the 1980s, when scientists developed methods to reach the canopy, such as firing ropes into the trees using crossbows . Exploration of the canopy is still in its infancy, but other methods include the use of balloons and airships to float above the highest branches and

2730-560: The NFIP as the Special Flood Hazard Area. Where a detailed study of a waterway has been done, the 100-year floodplain will also include the floodway, the critical portion of the floodplain which includes the stream channel and any adjacent areas that must be kept free of encroachments that might block flood flows or restrict storage of flood waters. Another commonly encountered term is the Special Flood Hazard Area, which

2808-401: The Ord River and Parry Lagoons nature reserves , with some additional land. It lies downstream of two large impoundments on the Ord River, Lakes Argyle and Kununurra , which have had a major impact on the river's hydrology through changing its flow pattern so that there are now constant flows through the dry season . In effect, the lower Ord has been transformed through flow regulation at

2886-400: The abandoned floodplain may be preserved as fluvial terraces . Floodplains support diverse and productive ecosystems . They are characterized by considerable variability in space and time, which in turn produces some of the most species-rich of ecosystems. From the ecological perspective, the most distinctive aspect of floodplains is the flood pulse associated with annual floods, and so

2964-511: The advantages provided by the richness of the alluvial soil of the floodplain are severely offset by frequent floods brought on by cyclones and annual monsoon rains. These extreme weather events cause severe economic disruption and loss of human life in the densely-populated region. Floodplain soil composition is unique and varies widely based on microtopography. Floodplain forests have high topographic heterogeneity which creates variation in localized hydrologic conditions. Soil moisture within

3042-464: The building of cranes and walkways planted on the forest floor. The science of accessing tropical forest canopy using airships or similar aerial platforms is called dendronautics . The understory or understorey layer lies between the canopy and the forest floor. It is home to a number of birds , snakes and lizards , as well as predators such as jaguars , boa constrictors and leopards . The leaves are much larger at this level and insect life

3120-467: The channel shifts varies greatly, with reported rates ranging from too slow to measure to as much as 2,400 feet (730 m) per year for the Kosi River of India. Overbank flow takes place when the river is flooded with more water than can be accommodated by the river channel. Flow over the banks of the river deposits a thin veneer of sediments that is coarsest and thickest close to the channel. This

3198-406: The dams from a ‘dry tropics’ to a ‘wet tropics’ river. The southern part of the site is dominated by Parry Creek, including 20 kilometres (12 mi) of seasonal creek and an alluvial floodplain which is flooded during the wet season . It dries out quickly in the dry season , except for waterholes associated with incised channels and claypans . The southern, or upstream, part of the floodplain

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3276-417: The decomposing remains of plants and animals. The great diversity in rainforest species is in large part the result of diverse and numerous physical refuges , i.e. places in which plants are inaccessible to many herbivores, or in which animals can hide from predators. Having numerous refuges available also results in much higher total biomass than would otherwise be possible. Some species of fauna show

3354-472: The flood waters. This can encourage farming ; some important agricultural regions, such as the Nile and Mississippi river basins , heavily exploit floodplains. Agricultural and urban regions have developed near or on floodplains to take advantage of the rich soil and freshwater. However, the risk of inundation has led to increasing efforts to control flooding . Most floodplains are formed by deposition on

3432-448: The floodplain ecosystem is defined as the part of the river valley that is regularly flooded and dried. Floods bring in detrital material rich in nutrients and release nutrients from dry soil as it is flooded. The decomposition of terrestrial plants submerged by the floodwaters adds to the nutrient supply. The flooded littoral zone of the river (the zone closest to the river bank) provides an ideal environment for many aquatic species, so

3510-462: The floodplain has a big impact on phosphorus availability because it alters water level, redox state, pH, and physical properties of minerals. Dry soils that were previously inundated have reduced availability of phosphorus and increased affinity for obtaining phosphorus. Human floodplain alterations also impact the phosphorus cycle. Particulate phosphorus and soluble reactive phosphorus (SRP) can contribute to algal blooms and toxicity in waterways when

3588-599: The floodplain. Other smaller-scale mitigation efforts include acquiring and demolishing flood-prone buildings or flood-proofing them. In some floodplains, such as the Inner Niger Delta of Mali , annual flooding events are a natural part of the local ecology and rural economy , allowing for the raising of crops through recessional agriculture . However, in Bangladesh , which occupies the Ganges Delta ,

3666-699: The globe, but temperate rainforests only occur in a few regions around the world. Temperate rainforests are rainforests in temperate regions. They occur in North America (in the Pacific Northwest in Alaska , British Columbia , Washington , Oregon and California ), in Europe (parts of the British Isles such as the coastal areas of Ireland and Scotland , southern Norway , parts of

3744-422: The growth of vegetation in a tropical rainforest, soil quality is often quite poor. Rapid bacterial decay prevents the accumulation of humus . The concentration of iron and aluminium oxides by the laterization process gives the oxisols a bright red colour and sometimes produces mineral deposits such as bauxite . Most trees have roots near the surface because there are insufficient nutrients below

3822-439: The human-caused disconnect between floodplains and rivers exacerbates the phosphorus overload. Floodplain soils tend to be high in eco-pollutants, especially persistent organic pollutant (POP) deposition. Proper understanding of the distribution of soil contaminants is difficult because of high variation in microtopography and soil texture within floodplains. Rainforest Rainforests are forests characterized by

3900-465: The impact of floodwaters. The disturbance by humans of temperate floodplain ecosystems frustrates attempts to understand their natural behavior. Tropical rivers are less impacted by humans and provide models for temperate floodplain ecosystems, which are thought to share many of their ecological attributes. Excluding famines and epidemics , some of the worst natural disasters in history (measured by fatalities) have been river floods, particularly in

3978-473: The increasing deforestation rate, especially in Indonesia, is the expansion of oil palm plantations to meet growing demand for cheap vegetable fats and biofuels . In Indonesia, palm oil is already cultivated on nine million hectares and, together with Malaysia , the island nation produces about 85 percent of the world's palm oil. Several countries, notably Brazil , have declared their deforestation

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4056-448: The inside of river meanders and by overbank flow. Wherever the river meanders, the flowing water erodes the river bank on the outside of the meander. At the same time, sediments are simultaneously deposited in a bar on the inside of the meander. This is described as lateral accretion since the deposition builds the point bar laterally into the river channel. Erosion on the outside of the meander usually closely balances deposition on

4134-417: The inside so that the channel shifts in the direction of the meander without changing significantly in width. The point bar is built up to a level very close to that of the river banks. Significant net erosion of sediments occurs only when the meander cuts into higher ground. The overall effect is that, as the river meanders, it creates a level flood plain composed mostly of point bar deposits. The rate at which

4212-477: The interior". About half of Sarawak's 1.5 million people are Dayaks. Most Dayaks, it is believed by anthropologists, came originally from the South-East Asian mainland. Their mythologies support this. Tropical and temperate rainforests have been subjected to heavy legal and illegal logging for their valuable hardwoods and agricultural clearance ( slash-and-burn , clearcutting ) throughout

4290-514: The island of New Guinea is home to an estimated 44 uncontacted tribal groups. The tribes are in danger because of the deforestation, especially in Brazil. Central African rainforest is home of the Mbuti pygmies , one of the hunter-gatherer peoples living in equatorial rainforests characterised by their short height (below one and a half metres, or 59 inches, on average). They were the subject of

4368-457: The levees (4 kg/m or more) and on low-lying areas (1.6 kg/m ). Sedimentation from the overbank flow is concentrated on natural levees, crevasse splays , and in wetlands and shallow lakes of flood basins. Natural levees are ridges along river banks that form from rapid deposition from the overbank flow. Most of the suspended sand is deposited on the levees, leaving the silt and clay sediments to be deposited as floodplain mud further from

4446-437: The majority of the largest trees, typically 30 metres (98 ft) to 45 metres (148 ft) tall. The densest areas of biodiversity are found in the forest canopy, a more or less continuous cover of foliage formed by adjacent treetops. The canopy, by some estimates, is home to 50 percent of all plant species. Epiphytic plants attach to trunks and branches , and obtain water and minerals from rain and debris that collects on

4524-617: The makeup towards ash (49%) with maple increasing to 14% and oak decreasing to 25%. Semiarid floodplains have a much lower species diversity. Species are adapted to alternating drought and flood. Extreme drying can destroy the ability of the floodplain ecosystem to shift to a healthy wet phase when flooded. Floodplain forests constituted 1% of the landscape of Europe in the 1800s. Much of this has been cleared by human activity, though floodplain forests have been impacted less than other kinds of forests. This makes them important refugia for biodiversity. Human destruction of floodplain ecosystems

4602-535: The mangroves. Other occasional species of mangrove include Xylocarpus moluccensis , Excoecaria agallocha and Camptostemon schultzii . The seasonal wetlands on the floodplain regularly support large numbers of waterbirds. Numerically important duck species include hardhead , grey teal and plumed whistling duck . The lagoons are also an important site for shorebirds : several thousand little curlews and Oriental pratincoles , and hundreds of wood sandpipers have been counted. The Parry Lagoons are probably

4680-459: The most important site in Australia for both wood and marsh sandpipers . When local rainfall is high the lagoons and other seasonal wetlands are major breeding areas for waterbirds in the Kimberley, with up to 77 species recorded in habitats associated with Parry Creek. The grasslands are the only place in Western Australia where zitting cisticolas occur naturally. The mangroves contain 12 of

4758-762: The nitrogen-to-phosphorus ratios are altered farther upstream. In areas where the phosphorus load is primarily particulate phosphorus, like the Mississippi River, the most effective ways of removing phosphorus upstream are sedimentation, soil accretion, and burial. In basins where SRP is the primary form of phosphorus, biological uptake in floodplain forests is the best way of removing nutrients. Phosphorus can transform between SRP and particulate phosphorus depending on ambient conditions or processes like decomposition, biological uptake, redoximorphic release, and sedimentation and accretion. In either phosphorus form, floodplain forests are beneficial as phosphorus sinks, and

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4836-473: The poor soil quality. First is that the soil is highly acidic. The roots of plants rely on an acidity difference between the roots and the soil in order to absorb nutrients. When the soil is acidic, there is little difference, and therefore little absorption of nutrients from the soil. Second, the type of clay particles present in tropical rainforest soil has a poor ability to trap nutrients and stop them from washing away. Even if humans artificially add nutrients to

4914-708: The rainforests. Another factor causing the loss of rainforest is expanding urban areas . Littoral rainforest growing along coastal areas of eastern Australia is now rare due to ribbon development to accommodate the demand for seachange lifestyles. Forests are being destroyed at a rapid pace. Almost 90% of West Africa 's rainforest has been destroyed. Since the arrival of humans, Madagascar has lost two thirds of its original rainforest. At present rates, tropical rainforests in Indonesia would be logged out in 10 years and Papua New Guinea in 13 to 16 years. According to Rainforest Rescue , an important reason for

4992-580: The river may abandon the channel belt and build a new one at another position on the floodplain. This process is called avulsion and occurs at intervals of 10–1000 years. Historical avulsions leading to catastrophic flooding include the 1855 Yellow River flood and the 2008 Kosi River flood . Floodplains can form around rivers of any kind or size. Even relatively straight stretches of river are capable of producing floodplains. Mid-channel bars in braided rivers migrate downstream through processes resembling those in point bars of meandering rivers and can build up

5070-511: The river, the successive plant communities are bank vegetation (usually annuals); sedge and reeds; willow shrubs; willow-poplar forest; oak-ash forest; and broadleaf forest. Human disturbance creates wet meadows that replace much of the original ecosystem. The biozones reflect a soil moisture and oxygen gradient that in turn corresponds to a flooding frequency gradient. The primeval floodplain forests of Europe were dominated by oak (60%) elm (20%) and hornbeam (13%), but human disturbance has shifted

5148-454: The river. The area is a regular tourist destination. Some exploration for alluvial diamonds takes place. The surrounding land is used for cattle grazing . 15°15′S 128°22′E  /  15.250°S 128.367°E  / -15.250; 128.367 Floodplain Because of regular flooding, floodplains frequently have high soil-fertility since nutrients are deposited with

5226-418: The river. Levees are typically built up enough to be relatively well-drained compared with nearby wetlands, and levees in non-arid climates are often heavily vegetated. Crevasses are formed by breakout events from the main river channel. The river bank fails, and floodwaters scour a channel. Sediments from the crevasse spread out as delta -shaped deposits with numerous distributary channels. Crevasse formation

5304-482: The same time, rainforests are usually not used sustainably by non-native peoples but are being exploited or removed for agricultural purposes . On January 18, 2007, FUNAI reported also that it had confirmed the presence of 67 different uncontacted tribes in Brazil, up from 40 in 2005. With this addition, Brazil has now overtaken the island of New Guinea as the country having the largest number of uncontacted tribes. The province of Irian Jaya or West Papua in

5382-605: The site include: the northern nail-tail wallaby , agile wallaby , long-haired rat and Kimberley rock rat . The critically endangered largetooth sawfish has been collected from the lower Ord River. Aboriginal people have a complex and spiritual relationship with the land and waters of the Ord River. The site lies within the traditional lands of the Miriuwung and Gajerrong language groups, and there are many cultural heritage sites, including those concerned with ceremonial, mythological and burial activities, associated with

5460-450: The site ten main vegetation associations have been identified: mudflats , mangroves, dune systems, grassland , low woodland , sandstone range open woodland, riverine woodland, rainforest ( aquifer forest) and spring vegetation, major rivers and lagoons (permanent and ephemeral), and savanna woodland. Some 335 native vascular plants from 89 families have been recorded from the site, with 16 introduced species. The eastern coast of

5538-560: The site the upstream end of the river channel is around 150 metres (490 ft) wide with broad sand and gravel spits , while unstable mud bars and islands characterise the 5 kilometres (3.1 mi) wide mouth. From the mouth of the Ord River, the site extends northwards around the coast to include the False mouths of the Ord , consisting of a maze of deltaic channels, intertidal mudflats and low muddy islands, an area which receives only

5616-421: The soil, the nutrients mostly wash away and are not absorbed by the plants. Finally, these soils are poor due to the high volume of rain in tropical rainforests washes nutrients out of the soil more quickly than in other climates. A natural rainforest emits and absorbs vast quantities of carbon dioxide . On a global scale, long-term fluxes are approximately in balance, so that an undisturbed rainforest would have

5694-408: The spawning season for fish often coincides with the onset of flooding. Fish must grow quickly during the flood to survive the subsequent drop in water level. As the floodwaters recede, the littoral experiences blooms of microorganisms, while the banks of the river dry out and terrestrial plants germinate to stabilize the bank. The biota of floodplains has high annual growth and mortality rates, which

5772-443: The supporting plants. The fauna is similar to that found in the emergent layer but more diverse. A quarter of all insect species are believed to exist in the rainforest canopy. Scientists have long suspected the richness of the canopy as a habitat, but have only recently developed practical methods of exploring it. As long ago as 1917, naturalist William Beebe declared that "another continent of life remains to be discovered, not upon

5850-433: The surface; most of the trees' minerals come from the top layer of decomposing leaves and animals. On younger substrates, especially of volcanic origin, tropical soils may be quite fertile. If rainforest trees are cleared, rain can accumulate on the exposed soil surfaces, creating run-off, and beginning a process of soil erosion . Eventually, streams and rivers form and flooding becomes possible. There are several reasons for

5928-459: The surrounding grade. Many State and local governments have, in addition, adopted floodplain construction regulations which are more restrictive than those mandated by the NFIP. The US government also sponsors flood hazard mitigation efforts to reduce flood impacts. California 's Hazard Mitigation Program is one funding source for mitigation projects. A number of whole towns such as English, Indiana , have been completely relocated to remove them from

6006-672: The upper 30 cm of the soil profile also varies widely based on microtopography which affects oxygen availability. Floodplain soil stays aerated for long stretches of time in between flooding events, but during flooding, saturated soil can become oxygen-depleted if it stands stagnant for long enough. More soil oxygen is available at higher elevations farther from the river. Floodplain forests generally experience alternating periods of aerobic and anaerobic soil microbe activity which affects fine root development and desiccation. Floodplains have high buffering capacity for phosphorus to prevent nutrient loss to river outputs. Phosphorus nutrient loading

6084-761: The western Balkans along the Adriatic coast, as well as in Galicia and coastal areas of the eastern Black Sea , including Georgia and coastal Turkey ), in East Asia (in southern China , Highlands of Taiwan , much of Japan and Korea , and on Sakhalin Island and the adjacent Russian Far East coast), in South America (southern Chile ) and also in Australia and New Zealand . Dry rainforests have

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