A stream is a continuous body of surface water flowing within the bed and banks of a channel . Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long, large streams are usually called rivers , while smaller, less voluminous and more intermittent streams are known as streamlets , brooks or creeks .
121-747: The Coliban River , an inland perennial river of the north–central catchment, part of the Murray-Darling basin , is located in the lower Riverina bioregion and Central Highlands region of the Australian state of Victoria . The headwaters of the Coliban River rise on the northern slopes of the Great Dividing Range and descend to flow north into the Campaspe River with the impounded Lake Eppalock . The river
242-590: A 2022 study published in Frontiers in Ecology and the Environment , a survey of more than 3,000 experts says that the extent of the mass extinction might be greater than previously thought, and estimates that roughly 30% of species "have been globally threatened or driven extinct since the year 1500." In a 2022 report, IPBES listed unsustainable fishing, hunting, and logging as some of the primary drivers of
363-615: A 2006 report by the Food and Agriculture Organization (FAO) of the United Nations, Livestock's Long Shadow , also found that the livestock sector is a "leading player" in biodiversity loss. More recently, in 2019, the IPBES Global Assessment Report on Biodiversity and Ecosystem Services attributed much of this ecological destruction to agriculture and fishing, with the meat and dairy industries having
484-403: A bed armor layer, and other depositional features, plus well defined banks due to bank erosion, are good identifiers when assessing for perennial streams. Particle size will help identify a perennial stream. Perennial streams cut through the soil profile, which removes fine and small particles. By assessing areas for relatively coarse material left behind in the stream bed and finer sediments along
605-514: A combined 50 billion years of Earth's evolutionary history (defined as phylogenetic diversity ) and driving to extinction some of the "most unique animals on the planet," among them the Aye-aye lemur, the Chinese crocodile lizard and the pangolin . Said lead author Rikki Gumbs: We know from all the data we have for threatened species, that the biggest threats are agriculture expansion and
726-658: A continuous aquatic habitat until they reach maturity. Crayfish and other crustaceans , snails , bivalves (clams), and aquatic worms also indicate the stream is perennial. These require a persistent aquatic environment for survival. Fish and amphibians are secondary indicators in assessment of a perennial stream because some fish and amphibians can inhabit areas without persistent water regime. When assessing for fish, all available habitat should be assessed: pools, riffles, root clumps and other obstructions. Fish will seek cover if alerted to human presence, but should be easily observed in perennial streams. Amphibians also indicate
847-470: A continuous or intermittent stream. The same non-perennial channel might change characteristics from intermittent to ephemeral over its course. Washes can fill up quickly during rains, and there may be a sudden torrent of water after a thunderstorm begins upstream, such as during monsoonal conditions. In the United States, an intermittent or seasonal stream is one that only flows for part of
968-615: A creek, especially one that is fed by a spring or seep . It is usually small and easily forded . A brook is characterised by its shallowness. A creek ( / k r iː k / ) or crick ( / k r ɪ k / ): In hydrography, gut is a small creek; this is seen in proper names in eastern North America from the Mid-Atlantic states (for instance, The Gut in Pennsylvania, Ash Gut in Delaware, and other streams) down into
1089-422: A drainage network. Although each tributary has its own source, international practice is to take the source farthest from the river mouth as the source of the entire river system, from which the most extended length of the river measured as the starting point is taken as the length of the whole river system, and that furthest starting point is conventionally taken as the source of the whole river system. For example,
1210-496: A fringe theory. Contemporary human overpopulation and continued population growth , along with per-capita consumption growth, prominently in the past two centuries, are regarded as the underlying causes of extinction. Inger Andersen , the executive director of the United Nations Environment Programme , stated that "we need to understand that the more people there are, the more we put
1331-680: A global mass extinction of wildlife. We ignore the decline of other species at our peril – for they are the barometer that reveals our impact on the world that sustains us. A 2023 study published in Current Biology concluded that current biodiversity loss rates could reach a tipping point and inevitably trigger a total ecosystem collapse. Recent extinctions are more directly attributable to human influences, whereas prehistoric extinctions can be attributed to other factors. The International Union for Conservation of Nature (IUCN) characterizes 'recent' extinction as those that have occurred past
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#17327725907391452-466: A global scale and eliminate billions of years of phylogenetic diversity . 189 countries, which are signatory to the Convention on Biological Diversity (Rio Accord), have committed to preparing a Biodiversity Action Plan , a first step at identifying specific endangered species and habitats, country by country . For the first time since the demise of the dinosaurs 65 million years ago, we face
1573-566: A global scale, and when these alterations caused changes to global climate. Using chemical proxies from Antarctic ice cores, researchers have estimated the fluctuations of carbon dioxide (CO 2 ) and methane (CH 4 ) gases in the Earth's atmosphere during the Late Pleistocene and Holocene epochs. Estimates of the fluctuations of these two gases in the atmosphere, using chemical proxies from Antarctic ice cores, generally indicate that
1694-542: A great deal of influence over food webs and climatic systems worldwide. Although significant debate exists as to how much human predation and indirect effects contributed to prehistoric extinctions, certain population crashes have been directly correlated with human arrival. Human activity has been the main cause of mammalian extinctions since the Late Pleistocene. A 2018 study published in PNAS found that since
1815-540: A larger stream. Common terms for individual river distributaries in English-speaking countries are arm and channel . There are a number of regional names for a stream. A stream's source depends on the surrounding landscape and its function within larger river networks. While perennial and intermittent streams are typically supplied by smaller upstream waters and groundwater, headwater and ephemeral streams often derive most of their water from precipitation in
1936-737: A longer Holocene extinction. The Holocene–Anthropocene boundary is contested, with some commentators asserting significant human influence on climate for much of what is normally regarded as the Holocene Epoch . Some experts mark the transition from the Holocene to the Anthropocene at the onset of the industrial revolution . They also note that the official use of this term in the near future will heavily rely on its usefulness, especially for Earth scientists studying late Holocene periods. It has been suggested that human activity has made
2057-445: A mass extinction event, the sixth in roughly 540 million years, wherein many current life forms could be extirpated or at least committed to extinction by the end of this century." The World Wide Fund for Nature 's 2020 Living Planet Report says that wildlife populations have declined by 68% since 1970 as a result of overconsumption , population growth , and intensive farming , which is further evidence that humans have unleashed
2178-424: A number of human-derived factors are recognized as contributing to rising atmospheric concentrations of CH 4 (methane) and CO 2 (carbon dioxide), deforestation and territorial clearance practices associated with agricultural development may have contributed most to these concentrations globally in earlier millennia. Scientists that are employing a variance of archaeological and paleoecological data argue that
2299-404: A path into mines or other underground chambers. According to official U.S. definitions, the channels of intermittent streams are well-defined, as opposed to ephemeral streams, which may or may not have a defined channel, and rely mainly on storm runoff, as their aquatic bed is above the water table . An ephemeral stream does not have the biological, hydrological, and physical characteristics of
2420-412: A perennial stream and include tadpoles , frogs , salamanders , and newts . These amphibians can be found in stream channels, along stream banks, and even under rocks. Frogs and tadpoles usually inhabit shallow and slow moving waters near the sides of stream banks. Frogs will typically jump into water when alerted to human presence. Well defined river beds composed of riffles, pools, runs, gravel bars,
2541-483: A perennial stream, fine sediment may cling to riparian plant stems and tree trunks. Organic debris drift lines or piles may be found within the active overbank area after recent high flow. Streams, headwaters, and streams flowing only part of the year provide many benefits upstream and downstream. They defend against floods, remove contaminants, recycle nutrients that are potentially dangerous as well as provide food and habitat for many forms of fish. Such streams also play
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#17327725907392662-821: A similar study drawing on work at the University of Queensland , which found that "more than 1,200 species globally face threats to their survival in more than 90% of their habitat and will almost certainly face extinction without conservation intervention". Since 1970, the populations of migratory freshwater fish have declined by 76%, according to research published by the Zoological Society of London in July 2020. Overall, around one in three freshwater fish species are threatened with extinction due to human-driven habitat degradation and overfishing. Some scientists and academics assert that industrial agriculture and
2783-827: A sixth mass extinction event caused by anthropogenic activity is currently under way. A December 2022 study published in Science Advances states that "the planet has entered the sixth mass extinction" and warns that current anthropogenic trends, particularly regarding climate and land-use changes , could result in the loss of more than a tenth of plant and animal species by the end of the century. 12% of all bird species are threatened with extinction. A 2023 study published in Biological Reviews found that, of 70,000 monitored species, some 48% are experiencing population declines from anthropogenic pressures, whereas only 3% have increasing populations. According to
2904-540: A sixth mass extinction event; however, this finding has been disputed by one 2020 study, which posits that this major decline was primarily driven by a few extreme outlier populations, and that when these outliers are removed, the trend shifts to that of a decline between the 1980s and 2000s, but a roughly positive trend after 2000. A 2021 report in Frontiers in Conservation Science which cites both of
3025-406: A slow-moving wetted channel or stagnant area. This is evidence that iron-oxidizing bacteria are present, indicating persistent expression of oxygen-depleted ground water. In a forested area, leaf and needle litter in the stream channel is an additional indicator. Accumulation of leaf litter does not occur in perennial streams since such material is continuously flushed. In the adjacent overbank of
3146-486: A stream as intermittent, "showing interruptions in time or space". Generally, streams that flow only during and immediately after precipitation are termed ephemeral . There is no clear demarcation between surface runoff and an ephemeral stream, and some ephemeral streams can be classed as intermittent—flow all but disappearing in the normal course of seasons but ample flow (backups) restoring stream presence — such circumstances are documented when stream beds have opened up
3267-424: A stream is a critical factor in determining its character and is entirely determined by its base level of erosion. The base level of erosion is the point at which the stream either enters the ocean, a lake or pond, or enters a stretch in which it has a much lower gradient, and may be specifically applied to any particular stretch of a stream. In geological terms, the stream will erode down through its bed to achieve
3388-524: A thin layer called sheet wash, combined with a network of tiny rills, which together form the sheet runoff; when this water is focused in a channel, a stream is born. Some rivers and streams may begin from lakes or ponds. Freshwater's primary sources are precipitation and mountain snowmelt. However, rivers typically originate in the highlands, and are slowly created by the erosion of mountain snowmelt into lakes or rivers. Rivers usually flow from their source topographically, and erode as they pass until they reach
3509-511: A very significant impact. Since the 1970s food production has soared to feed a growing human population and bolster economic growth, but at a huge price to the environment and other species. The report says some 25% of the Earth's ice-free land is used for cattle grazing. A 2020 study published in Nature Communications warned that human impacts from housing, industrial agriculture and in particular meat consumption are wiping out
3630-627: A vital role in preserving our drinking water quality and supply, ensuring a steady flow of water to surface waters and helping to restore deep aquifers. The extent of land basin drained by a stream is termed its drainage basin (also known in North America as the watershed and, in British English, as a catchment). A basin may also be composed of smaller basins. For instance, the Continental Divide in North America divides
3751-524: Is a big risk. The 2011 study by Barnosky et al. confirms that "current extinction rates are higher than would be expected from the fossil record" and adds that anthropogenic ecological stressors, including climate change, habitat fragmentation , pollution, overfishing, overhunting, invasive species, and expanding human biomass , will intensify and accelerate extinction rates in the future without significant mitigation efforts. In The Future of Life (2002), Edward Osborne Wilson of Harvard calculated that, if
Coliban River - Misplaced Pages Continue
3872-678: Is a major water supply source for towns and cities in the lower Central Highlands region. The river rises below Little Hampton near Lyonville in the Great Dividing Range and flows generally north, descending 33 metres (108 ft) over the Trentham Falls, and continuing to flow northward to the Upper Coliban, Lauriston and Malmsbury reservoirs. Subsequently, it flows through Malmsbury , Metcalfe , Redesdale and Mintaro , and finally reaches its confluence with
3993-435: Is a stream that branches off and flows away from a main stream channel, and the phenomenon is known as river bifurcation . Distributaries are common features of river deltas , and are often found where a valleyed stream enters wide flatlands or approaches the coastal plains around a lake or an ocean . They can also occur inland, on alluvial fans , or where a tributary stream bifurcates as it nears its confluence with
4114-477: Is impacting larger mammals and birds to a much greater extent than smaller ones, with the body mass of such animals expected to shrink by 25% over the next century. Another 2019 study published in Biology Letters found that extinction rates are perhaps much higher than previously estimated, in particular for bird species. The 2019 Global Assessment Report on Biodiversity and Ecosystem Services lists
4235-555: Is primarily driven by human activity. This has resulted in empty forests , ecological communities depleted of large vertebrates. This is not to be confused with extinction, as it includes both the disappearance of species and declines in abundance. Defaunation effects were first implied at the Symposium of Plant-Animal Interactions at the University of Campinas, Brazil in 1988 in the context of Neotropical forests . Since then,
4356-425: Is sometimes termed a "young" or "immature" stream, and the later state a "mature" or "old" stream. Meanders are looping changes of direction of a stream caused by the erosion and deposition of bank materials. These are typically serpentine in form. Typically, over time the meanders gradually migrate downstream. If some resistant material slows or stops the downstream movement of a meander, a stream may erode through
4477-514: Is the current geological epoch . There is no general agreement on when the Holocene , or anthropogenic , extinction begins, and the Quaternary extinction event , which includes climate change resulting in the end of the last ice age , ends, or if they should be considered separate events at all. The Holocene extinction is mainly caused by human activities. Some authors have argued that
4598-456: Is usually called a creek and marked on topographic maps with a solid blue line. There are five generic classifications: "Macroinvertebrate" refers to easily seen invertebrates , larger than 0.5 mm, found in stream and river bottoms. Macroinvertebrates are larval stages of most aquatic insects and their presence is a good indicator that the stream is perennial. Larvae of caddisflies , mayflies , stoneflies , and damselflies require
4719-597: The Atlantic , and of the leatherback sea turtle in Malaysia. Since the Late Pleistocene, humans (together with other factors) have been rapidly driving the largest vertebrate animals towards extinction, and in the process interrupting a 66-million-year-old feature of ecosystems, the relationship between diet and body mass, which researchers suggest could have unpredictable consequences. A 2019 study published in Nature Communications found that rapid biodiversity loss
4840-464: The Campaspe River within Lake Eppalock . The river descends 518 metres (1,699 ft) over its 89-kilometre (55 mi) course . Gold was found in the river in 1858, and water from the river was used to supply the goldfields cities of Bendigo and Castlemaine . As the population of those cities grew a water supply system consisting of 70 kilometres (43 mi) of tunnels and aqueducts
4961-538: The Macquarie perch . Four of the fish species are endangered and the trout cod is regarded as critically endangered in the river, and may no longer be present. Indigenous vegetation in the area includes the black gum ( Eucalyptus aggregata ) which, though once plentiful in the area, is now rare due to vegetation clearance over many years. In the Aboriginal Djadjawurrung language , the name for
Coliban River - Misplaced Pages Continue
5082-760: The Ordovician–Silurian extinction events , the Late Devonian extinction , the Permian–Triassic extinction event , the Triassic–Jurassic extinction event , and the Cretaceous–Paleogene extinction event . If the Capitanian extinction event is included among the first-order mass extinctions, the Holocene extinction would correspondingly be known as the "seventh extinction". The Holocene
5203-620: The Pleistocene . Over the course of the Late Holocene, there were hundreds of extinctions of birds on islands across the Pacific, driven by human settlement of the previously uninhabited islands, with extinctions peaking around 1300 AD. Roughly 12% of avian species have been driven to extinction by human activity over the last 126,000 years, which is double previous estimates. In the twentieth century, human numbers quadrupled, and
5324-691: The Tombigbee River basin. Continuing in this vein, a component of the Mississippi River basin is the Ohio River basin, which in turn includes the Kentucky River basin, and so forth. Stream crossings are where streams are crossed by roads , pipelines , railways , or any other thing which might restrict the flow of the stream in ordinary or flood conditions. Any structure over or in a stream which results in limitations on
5445-621: The UNDP 's 2020 Human Development Report , The Next Frontier: Human Development and the Anthropocene : The planet's biodiversity is plunging, with a quarter of species facing extinction, many within decades. Numerous experts believe we are living through, or on the cusp of, a mass species extinction event, the sixth in the history of the planet and the first to be caused by a single organism—us. The 2022 Living Planet Report found that vertebrate wildlife populations have plummeted by an average of almost 70% since 1970, with agriculture and fishing being
5566-593: The United States Chamber of Commerce , have been pushing back against legislation that could address the extinction crisis. A 2022 report by the climate think tank InfluenceMap stated that "although industry associations, especially in the US, appear reluctant to discuss the biodiversity crisis, they are clearly engaged on a wide range of policies with significant impacts on biodiversity loss." The loss of animal species from ecological communities, defaunation ,
5687-404: The decline of insect populations are associated with intensive farming practices, along with pesticide use and climate change. The world's insect population decreases by around 1 to 2% per year. We have driven the rate of biological extinction, the permanent loss of species, up several hundred times beyond its historical levels, and are threatened with the loss of a majority of all species by
5808-480: The velocity of the stream. A perennial stream is one which flows continuously all year. Some perennial streams may only have continuous flow in segments of its stream bed year round during years of normal rainfall. Blue-line streams are perennial streams and are marked on topographic maps with a solid blue line. The word "perennial" from the 1640s, meaning "evergreen," is established in Latin perennis, keeping
5929-433: The "Anthropocene extinction". Anthropocene is a term introduced in 2000. Some now postulate that a new geological epoch has begun, with the most abrupt and widespread extinction of species since the Cretaceous–Paleogene extinction event 66 million years ago. The term "anthropocene" is being used more frequently by scientists, and some commentators may refer to the current and projected future extinctions as part of
6050-704: The Caribbean (for instance, Guinea Gut , Fish Bay Gut , Cob Gut , Battery Gut and other rivers and streams in the United States Virgin Islands , in Jamaica (Sandy Gut, Bens Gut River, White Gut River), and in many streams and creeks of the Dutch Caribbean ). A river is a large natural stream that is much wider and deeper than a creek and not easily fordable, and may be a navigable waterway . The linear channel between
6171-404: The Earth under heavy pressure. As far as biodiversity is concerned, we are at war with nature." Some scholars assert that the emergence of capitalism as the dominant economic system has accelerated ecological exploitation and destruction, and has also exacerbated mass species extinction. CUNY professor David Harvey , for example, posits that the neoliberal era "happens to be the era of
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#17327725907396292-446: The Holocene extinction can be linked to the human impact on the environment . The Holocene extinction continues into the 21st century, with anthropogenic global warming , human population growth , increasing per capita consumption (especially by the super- affluent ), and meat production and consumption , among others, being the primary drivers of mass extinction. Deforestation , overfishing , ocean acidification ,
6413-434: The Holocene extinction event. The Holocene extinction follows the extinction of the majority of large (megafaunal) animals during the preceding Late Pleistocene . Some of these extinctions were likely in part due to human hunting pressure. The most popular theory is that human overhunting of species added to existing stress conditions as the Holocene extinction coincides with human colonization of many new areas around
6534-477: The activities of earlier archaic humans have also resulted in extinctions, though the evidence for this is equivocal; this is supported by rapid megafaunal extinction following recent human colonization in Australia , New Zealand , and Madagascar . In many cases, it is suggested that even minimal hunting pressure was enough to wipe out large fauna, particularly on geographically isolated islands. Only during
6655-536: The aforementioned studies, says "population sizes of vertebrate species that have been monitored across years have declined by an average of 68% over the last five decades, with certain population clusters in extreme decline, thus presaging the imminent extinction of their species," and asserts "that we are already on the path of a sixth major extinction is now scientifically undeniable." A January 2022 review article published in Biological Reviews builds upon previous studies documenting biodiversity decline to assert that
6776-533: The atmosphere either by evaporation from soil and water bodies, or by plant evapotranspiration. By infiltration some of the water sinks into the earth and becomes groundwater, much of which eventually enters streams. Most precipitated water is partially bottled up by evaporation or freezing in snow fields and glaciers. The majority of the water flows as a runoff from the ground; the proportion of this varies depending on several factors, such as climate, temperature, vegetation, types of rock, and relief. This runoff begins as
6897-407: The atmosphere was the growth of human agriculture during the Holocene. One of the main theories explaining early Holocene extinctions is historic climate change . The climate change theory has suggested that a change in climate near the end of the late Pleistocene stressed the megafauna to the point of extinction. Some scientists favor abrupt climate change as the catalyst for the extinction of
7018-525: The base level of erosion throughout its course. If this base level is low, then the stream will rapidly cut through underlying strata and have a steep gradient, and if the base level is relatively high, then the stream will form a flood plain and meander. Typically, streams are said to have a particular elevation profile , beginning with steep gradients, no flood plain, and little shifting of channels, eventually evolving into streams with low gradients, wide flood plains, and extensive meanders. The initial stage
7139-538: The base stage of erosion. The scientists have offered a way based on data to define the origin of the lake. A classified sample was the one measured by the Chinese researchers from the University of Chinese Academy of Sciences. As an essential symbol of the river formation environment, the river source needs an objective and straightforward and effective method of judging . A calculation model of river source catchment area based on critical support flow (CSD) proposed, and
7260-593: The biomass of insect life in Germany had declined by three-quarters in the previous 25 years. Participating researcher Dave Goulson of Sussex University stated that their study suggested that humans are making large parts of the planet uninhabitable for wildlife. Goulson characterized the situation as an approaching "ecological Armageddon", adding that "if we lose the insects then everything is going to collapse." A 2019 study found that over 40% of insect species are threatened with extinction. The most significant drivers in
7381-430: The case that early farmers involved in systems of agriculture used more land per capita than growers later in the Holocene, who intensified their labor to produce more food per unit of area (thus, per laborer); arguing that agricultural involvement in rice production implemented thousands of years ago by relatively small populations created significant environmental impacts through large-scale means of deforestation. While
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#17327725907397502-553: The current rate of human disruption of the biosphere continues, one-half of Earth's higher lifeforms will be extinct by 2100. A 1998 poll conducted by the American Museum of Natural History found that 70% of biologists acknowledge an ongoing anthropogenic extinction event. In a pair of studies published in 2015, extrapolation from observed extinction of Hawaiian snails led to the conclusion that 7% of all species on Earth may have been lost already. A 2021 study published in
7623-527: The cut-off point of 1500, and at least 875 plant and animal species have gone extinct since that time and 2009. Some species, such as the Père David's deer and the Hawaiian crow , are extinct in the wild, and survive solely in captive populations. Other populations are only locally extinct (extirpated), still existent elsewhere, but reduced in distribution, as with the extinction of gray whales in
7744-467: The dawn of human civilization, the biomass of wild mammals has decreased by 83%. The biomass decrease is 80% for marine mammals, 50% for plants, and 15% for fish. Currently, livestock make up 60% of the biomass of all mammals on Earth, followed by humans (36%) and wild mammals (4%). As for birds, 70% are domesticated, such as poultry, whereas only 30% are wild. Extinction of animals, plants, and other organisms caused by human actions may go as far back as
7865-430: The destruction of wetlands , and the decline in amphibian populations , among others, are a few broader examples of global biodiversity loss . Mass extinctions are characterized by the loss of at least 75% of species within a geologically short period of time (i.e., less than 2 million years). The Holocene extinction is also known as the "sixth extinction", as it is possibly the sixth mass extinction event, after
7986-455: The destruction of habitats, the consumption of animals as resources, and the elimination of species that humans view as threats or competitors. Rising extinction trends impacting numerous animal groups including mammals, birds, reptiles, and amphibians have prompted some scientists to declare a biodiversity crisis. The description of recent extinction as a mass extinction has been debated among scientists. Stuart Pimm , for example, asserts that
8107-441: The end of the 21st century. Various species are predicted to become extinct in the near future , among them some species of rhinoceros , primates , and pangolins . Others, including several species of giraffe, are considered " vulnerable " and are experiencing significant population declines from anthropogenic impacts including hunting, deforestation and conflict. Hunting alone threatens bird and mammalian populations around
8228-435: The estimate put forward in the 2019 IPBES report. According to a 2023 study published in PNAS , at least 73 genera of animals have gone extinct since 1500. If humans had never existed, the study estimates it would have taken 18,000 years for the same genera to have disappeared naturally, leading the authors to conclude that "the current generic extinction rates are 35 times higher than expected background rates prevailing in
8349-462: The exception of Africa. Over the past 130,000 years, avian functional diversity has declined precipitously and disproportionately relative to phylogenetic diversity losses. Human civilization was founded on and grew from agriculture. The more land used for farming, the greater the population a civilization could sustain, and subsequent popularization of farming led to widespread habitat conversion. Habitat destruction by humans , thus replacing
8470-482: The extinction event include deforestation , hunting, pollution, the introduction in various regions of non-native species , and the widespread transmission of infectious diseases spread through livestock and crops. Recent investigations into the practice of landscape burning during the Neolithic Revolution have a major implication for the current debate about the timing of the Anthropocene and
8591-444: The fastest mass extinction of species in the Earth's recent history". Ecologist William E. Rees concludes that the "neoliberal paradigm contributes significantly to planetary unraveling" by treating the economy and the ecosphere as totally separate systems, and by neglecting the latter. Major lobbying organizations representing corporations in the agriculture, fisheries, forestry and paper, mining, and oil and gas industries, including
8712-707: The flow is reduced to a trickle or less. Typically torrents have Apennine rather than Alpine sources, and in the summer they are fed by little precipitation and no melting snow. In this case the maximum discharge will be during the spring and autumn. An intermittent stream can also be called a winterbourne in Britain, a wadi in the Arabic -speaking world or torrente or rambla (this last one from arabic origin) in Spain and Latin America. In Australia, an intermittent stream
8833-447: The form of rain and snow. Most of this precipitated water re-enters the atmosphere by evaporation from soil and water bodies, or by the evapotranspiration of plants. Some of the water proceeds to sink into the earth by infiltration and becomes groundwater, much of which eventually enters streams. Some precipitated water is temporarily locked up in snow fields and glaciers , to be released later by evaporation or melting. The rest of
8954-546: The global extinction crisis. A 2022 study published in Science Advances suggests that if global warming reaches 2.7 °C (4.9 °F) or 4.4 °C (7.9 °F) by 2100, then 13% and 27% of terrestrial vertebrate species will go extinct by then, largely due to climate change (62%), with anthropogenic land conversion and co-extinctions accounting for the rest. A 2023 study published in PLOS One shows that around two million species are threatened with extinction, double
9075-598: The growing demand for meat is contributing to significant global biodiversity loss as this is a significant driver of deforestation and habitat destruction; species-rich habitats, such as the Amazon region and Indonesia being converted to agriculture. A 2017 study by the World Wildlife Fund (WWF) found that 60% of biodiversity loss can be attributed to the vast scale of feed crop cultivation required to rear tens of billions of farm animals. Moreover,
9196-408: The history of Earth. One scientist estimates the current extinction rate may be 10,000 times the background extinction rate , although most scientists predict a much lower extinction rate than this outlying estimate. Theoretical ecologist Stuart Pimm stated that the extinction rate for plants is 100 times higher than normal. Some contend that contemporary extinction has yet to reach the level of
9317-511: The illegal wildlife trade. Populations of brown bears have experienced similar population decline. The term pollinator decline refers to the reduction in abundance of insect and other animal pollinators in many ecosystems worldwide beginning at the end of the twentieth century, and continuing into the present day. Pollinators, which are necessary for 75% of food crops, are declining globally in both abundance and diversity. A 2017 study led by Radboud University's Hans de Kroon indicated that
9438-407: The immediate vicinity of a stream is called a riparian zone . Given the status of the ongoing Holocene extinction , streams play an important corridor role in connecting fragmented habitats and thus in conserving biodiversity . The study of streams and waterways in general is known as surface hydrology and is a core element of environmental geography . A brook is a stream smaller than
9559-646: The journal Frontiers in Forests and Global Change found that only around 3% of the planet's terrestrial surface is ecologically and faunally intact, meaning areas with healthy populations of native animal species and little or no human footprint. The 2019 Global Assessment Report on Biodiversity and Ecosystem Services , published by the United Nations' Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), posits that out of around eight million species of plants and animals, roughly one million species face extinction within decades as
9680-532: The lake has significant feeder rivers. The Kagera River, which flows into Lake Victoria near Bukoba's Tanzanian town , is the longest feeder, though sources do not agree on which is the Kagera's longest tributary and therefore the Nile's most remote source itself. To qualify as a stream, a body of water must be either recurring or perennial. Recurring (intermittent) streams have water in the channel for at least part of
9801-419: The last million years under the absence of human impacts" and that human civilization is causing the "rapid mutilation of the tree of life." We are currently, in a systematic manner, exterminating all non-human living beings. — Anne Larigauderie , IPBES executive secretary There is widespread consensus among scientists that human activity is accelerating the extinction of many animal species through
9922-416: The late Pleistocene , over 12,000 years ago. There is a correlation between megafaunal extinction and the arrival of humans. Megafauna that are still extant also suffered severe declines that were highly correlated with human expansion and activity. Over the past 125,000 years, the average body size of wildlife has fallen by 14% as actions by prehistoric humans eradicated megafauna on all continents with
10043-440: The leading cause in the next several decades. A June 2020 study published in PNAS posits that the contemporary extinction crisis "may be the most serious environmental threat to the persistence of civilization, because it is irreversible" and that its acceleration "is certain because of the still fast growth in human numbers and consumption rates." The study found that more than 500 vertebrate species are poised to be lost in
10164-683: The mainly easterly-draining Atlantic Ocean and Arctic Ocean basins from the largely westerly-flowing Pacific Ocean basin. The Atlantic Ocean basin, however, may be further subdivided into the Atlantic Ocean and Gulf of Mexico drainages. (This delineation is termed the Eastern Continental Divide .) Similarly, the Gulf of Mexico basin may be divided into the Mississippi River basin and several smaller basins, such as
10285-412: The meaning as "everlasting all year round," per "over" plus annus "year." This has been proved since the 1670s by the "living years" in the sense of botany. The metaphorical sense of "enduring, eternal" originates from 1750. They are related to "perennial." See biennial for shifts in vowels. Perennial streams have one or more of these characteristics: Absence of such characteristics supports classifying
10406-674: The megafauna at the end of the Pleistocene, most who believe increased hunting from early modern humans also played a part, with others even suggesting that the two interacted. In the Americas, a controversial explanation for the shift in climate is presented under the Younger Dryas impact hypothesis , which states that the impact of comets cooled global temperatures. Despite its popularity among nonscientists, this hypothesis never been accepted by relevant experts, who dismiss it as
10527-424: The most recent parts of the extinction have plants also suffered large losses . The contemporary rate of extinction of species is estimated at 100 to 1,000 times higher than the background extinction rate , the historically typical rate of extinction (in terms of the natural evolution of the planet); also, the current rate of extinction is 10 to 100 times higher than in any of the previous mass extinctions in
10648-590: The movement of fish or other ecological elements may be an issue. Holocene extinction The Holocene extinction , or Anthropocene extinction , is the ongoing extinction event caused by humans during the Holocene epoch. These extinctions span numerous families of plants and animals, including mammals , birds, reptiles, amphibians , fish, and invertebrates , and affecting not just terrestrial species but also large sectors of marine life . With widespread degradation of biodiversity hotspots , such as coral reefs and rainforests , as well as other areas,
10769-453: The neck between two legs of a meander to become temporarily straighter, leaving behind an arc-shaped body of water termed an oxbow lake or bayou . A flood may also cause a meander to be cut through in this way. The stream load is defined as the solid matter carried by a stream. Streams can carry sediment, or alluvium. The amount of load it can carry (capacity) as well as the largest object it can carry (competence) are both dependent on
10890-411: The next two decades. Biomass of mammals on Earth as of 2018 Humans both create and destroy crop cultivar and domesticated animal varieties. Advances in transportation and industrial farming has led to monoculture and the extinction of many cultivars. The use of certain plants and animals for food has also resulted in their extinction, including silphium and the passenger pigeon . It
11011-596: The origin of the Nile River is the confluence of the White Nile and the Blue Nile, but the source of the whole river system is in its upper reaches. If there is no specific designation, "length of the Nile" refers to the "river length of the Nile system", rather than to the length of the Nile river from the point where it is formed by a confluence of tributaries. The Nile's source is often cited as Lake Victoria, but
11132-424: The original local ecosystems, is a major driver of extinction. The sustained conversion of biodiversity rich forests and wetlands into poorer fields and pastures (of lesser carrying capacity for wild species), over the last 10,000 years, has considerably reduced the Earth's carrying capacity for wild birds and mammals, among other organisms, in both population size and species count. Other, related human causes of
11253-430: The other hand, has a relatively constant input and is controlled more by long-term patterns of precipitation. The stream encompasses surface, subsurface and groundwater fluxes that respond to geological, geomorphological, hydrological and biotic controls. Streams are important as conduits in the water cycle , instruments in groundwater recharge , and corridors for fish and wildlife migration. The biological habitat in
11374-415: The parallel ridges or bars on a shoreline beach or river floodplain, or between a bar and the shore. Also called a swale . A tributary is a contributory stream to a larger stream, or a stream which does not reach a static body of water such as a lake , bay or ocean but joins another river (a parent river). Sometimes also called a branch or fork. A distributary , or a distributary channel ,
11495-431: The patterns of the significant decline of CO 2 levels during the last ice age of the Pleistocene inversely correlate to the Holocene where there have been dramatic increases of CO 2 around 8000 years ago and CH 4 levels 3000 years after that. The correlation between the decrease of CO 2 in the Pleistocene and the increase of it during the Holocene implies that the causation of this spark of greenhouse gases into
11616-527: The peak of the Anthropocene occurred within the previous two centuries: typically beginning with the Industrial Revolution , when the highest greenhouse gas levels were recorded. A 2015 article in Science suggested that humans are unique in ecology as an unprecedented "global superpredator", regularly preying on large numbers of fully grown terrestrial and marine apex predators , and with
11737-605: The period starting from the mid-20th century different enough from the rest of the Holocene to consider it a new geological epoch , known as the Anthropocene, a term which was considered for inclusion in the timeline of Earth's history by the International Commission on Stratigraphy in 2016, but the proposal was rejected in 2024. To constitute the Holocene as an extinction event , scientists must determine exactly when anthropogenic greenhouse gas emissions began to measurably alter natural atmospheric levels on
11858-454: The point that most conservation biologists now believe that human activity has either produced a period of mass extinction, or is on the cusp of doing so. As such, after the "Big Five" mass extinctions , the Holocene extinction event has also been referred to as the sixth mass extinction or sixth extinction ; given the recent recognition of the Capitanian mass extinction , the term seventh mass extinction has also been proposed for
11979-461: The previous five mass extinctions, and that this comparison downplays how severe the first five mass extinctions were. John Briggs argues that there is inadequate data to determine the real rate of extinctions, and shows that estimates of current species extinctions varies enormously, ranging from 1.5 species to 40,000 species going extinct due to human activities each year. Both papers from Barnosky et al. (2011) and Hull et al. (2015) point out that
12100-470: The primary causes of contemporary extinctions in descending order: (1) changes in land and sea use (primarily agriculture and overfishing respectively); (2) direct exploitation of organisms such as hunting; (3) anthropogenic climate change; (4) pollution and (5) invasive alien species spread by human trade. This report, along with the 2020 Living Planet Report by the WWF, both project that climate change will be
12221-621: The primary drivers of this decline. Some scientists, including Rodolfo Dirzo and Paul R. Ehrlich , contend that the sixth mass extinction is largely unknown to most people globally and is also misunderstood by many in the scientific community. They say it is not the disappearance of species, which gets the most attention, that is at the heart of the crisis, but "the existential threat of myriad population extinctions." The abundance of species extinctions considered anthropogenic , or due to human activity, has sometimes (especially when referring to hypothesized future events) been collectively called
12342-436: The processes contributing to substantial human modification of the environment spanned many thousands of years on a global scale and thus, not originating as late as the Industrial Revolution . Palaeoclimatologist William Ruddiman has argued that in the early Holocene 11,000 years ago, atmospheric carbon dioxide and methane levels fluctuated in a pattern which was different from the Pleistocene epoch before it. He argued that
12463-418: The real rate of extinction during previous mass extinctions is unknown, because only some organisms leave fossil remains, and also the temporal resolution of the fossil layer is larger than the time frame of the extinction events. However, all these authors agree that there is a modern biodiversity crisis with population declines affecting numerous species, and that a future anthropogenic mass extinction event
12584-469: The relationship between CSA and CSD with a minimum catchment area established. Using the model for comparison in two basins in Tibet (Helongqu and Niyang River White Water), the results show that the critical support flow (Qc) of the housing dragon song is 0.0028 m /s. At the same time, the white water curvature is 0.0085 m /s. Besides, the critical support flow can vary with hydrologic climate conditions, and
12705-505: The result of human actions. Organized human existence is jeopardised by increasingly rapid destruction of the systems that support life on Earth, according to the report, the result of one of the most comprehensive studies of the health of the planet ever conducted. Moreover, the 2021 Economics of Biodiversity review, published by the UK government, asserts that "biodiversity is declining faster than at any time in human history." According to
12826-605: The river is Teeranyap , with no clearly defined meaning. In the Taungurung and Djadjawurrung languages, the names for the river is Pe-er , with no clearly defined meaning, and Dindelong yaluk , with yaluk meaning "river". Perennial river The flow of a stream is controlled by three inputs – surface runoff (from precipitation or meltwater ), daylighted subterranean water , and surfaced groundwater ( spring water ). The surface and subterranean water are highly variable between periods of rainfall. Groundwater, on
12947-482: The role that humans may have played in the production of greenhouse gases prior to the Industrial Revolution . Studies of early hunter-gatherers raise questions about the current use of population size or density as a proxy for the amount of land clearance and anthropogenic burning that took place in pre-industrial times. Scientists have questioned the correlation between population size and early territorial alterations. Ruddiman and Ellis' research paper in 2009 makes
13068-425: The side of the stream or within the floodplain will be a good indicator of persistent water regime. A perennial stream can be identified 48 hours after a storm. Direct storm runoff usually has ceased at this point. If a stream is still flowing and contributing inflow is not observed above the channel, the observed water is likely baseflow. Another perennial stream indication is an abundance of red rust material in
13189-450: The sixth mass extinction "is something that hasn't happened yet – we are on the edge of it." Several studies posit that the Earth has entered a sixth mass extinction event, including a 2015 paper by Barnosky et al. and a November 2017 statement titled " World Scientists' Warning to Humanity: A Second Notice ", led by eight authors and signed by 15,364 scientists from 184 countries which asserted, among other things, that "we have unleashed
13310-615: The size of the global economy increased twenty-five-fold. This Great Acceleration or Anthropocene epoch has also accelerated species extinction. Ecologically , humanity is now an unprecedented "global superpredator", which consistently preys on the adults of other apex predators , takes over other species' essential habitats and displaces them, and has worldwide effects on food webs . There are many famous examples of extinctions within Africa , Asia , Europe , Australia , North and South America , and on smaller islands. Overall,
13431-400: The term has gained broader usage in conservation biology as a global phenomenon. Big cat populations have severely declined over the last half-century and could face extinction in the following decades. According to 2011 IUCN estimates: lions are down to 25,000, from 450,000; leopards are down to 50,000, from 750,000; cheetahs are down to 12,000, from 45,000; tigers are down to 3,000 in
13552-404: The vast majority of these extinctions are thought to be undocumented, as the species are undiscovered at the time of their extinction, which goes unrecorded. The current rate of extinction of species is estimated at 100 to 1,000 times higher than natural background extinction rates and is increasing. During the past 100–200 years, biodiversity loss and species extinction have accelerated, to
13673-655: The vital support flow Qc in wet areas (white water) is larger than in semi-arid regions (heap slot). The proposed critical support flow (CSD) concept and model method can be used to determine the hydrographic indicators of river sources in complex geographical areas, and it can also reflect the impact of hydrologic climate change on river recharge in different regions. The source of a river or stream (its point of origin) can consist of lakes, swamps, springs, or glaciers. A typical river has several tributaries; each of these may be made up of several other smaller tributaries, so that together this stream and all its tributaries are called
13794-512: The water flows off the land as runoff, the proportion of which varies according to many factors, such as wind, humidity, vegetation, rock types, and relief. This runoff starts as a thin film called sheet wash, combined with a network of tiny rills, together constituting sheet runoff; when this water is concentrated in a channel, a stream has its birth. Some creeks may start from ponds or lakes. The streams typically derive most of their water from rain and snow precipitation. Most of this water re-enters
13915-538: The wild, from 50,000. A December 2016 study by the Zoological Society of London, Panthera Corporation and Wildlife Conservation Society showed that cheetahs are far closer to extinction than previously thought, with only 7,100 remaining in the wild, existing within only 9% of their historic range. Human pressures are to blame for the cheetah population crash, including prey loss due to overhunting by people, retaliatory killing from farmers, habitat loss and
14036-655: The world. The direct killing of megafauna for meat and body parts is the primary driver of their destruction, with 70% of the 362 megafauna species in decline as of 2019. Mammals in particular have suffered such severe losses as the result of human activity (mainly during the Quaternary extinction event , but partly during the Holocene) that it could take several million years for them to recover. Contemporary assessments have discovered that roughly 41% of amphibians, 25% of mammals, 21% of reptiles and 14% of birds are threatened with extinction, which could disrupt ecosystems on
14157-404: The world. Although there is debate regarding how much human predation and habitat loss affected their decline, certain population declines have been directly correlated with the onset of human activity, such as the extinction events of New Zealand , Madagascar, and Hawaii . Aside from humans, climate change may have been a driving factor in the megafaunal extinctions, especially at the end of
14278-521: The year and is marked on topographic maps with a line of blue dashes and dots. A wash , desert wash, or arroyo is normally a dry streambed in the deserts of the American Southwest , which flows after sufficient rainfall. In Italy, an intermittent stream is termed a torrent ( Italian : torrente ). In full flood the stream may or may not be "torrential" in the dramatic sense of the word, but there will be one or more seasons in which
14399-402: The year. A stream of the first order is a stream which does not have any other recurring or perennial stream feeding into it. When two first-order streams come together, they form a second-order stream. When two second-order streams come together, they form a third-order stream. Streams of lower order joining a higher order stream do not change the order of the higher stream. The gradient of
14520-517: Was constructed. Over time, the water supply was extended to Kyneton , as well as many other smaller towns in the region. Today, the system supplies drinking water to a population exceeding 200,000. Coliban Water manages the three major water supply reservoirs, which are part of the Eppalock Proclaimed Water Supply Catchment. The river is home to the platypus as well as eight native fish species, including
14641-450: Was estimated in 2012 that 13% of Earth's ice-free land surface is used as row-crop agricultural sites, 26% used as pastures, and 4% urban-industrial areas. In March 2019, Nature Climate Change published a study by ecologists from Yale University , who found that over the next half century, human land use will reduce the habitats of 1,700 species by up to 50%, pushing them closer to extinction. That same month PLOS Biology published
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