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Baikal Sturgeon
The Siberian sturgeon (''Acipenser baerii'') is a species of sturgeon in the family Acipenseridae. It is most present in all of the major Siberian river basins that drain northward into the Kara, Laptev and East Siberian Seas, including the Ob, Yenisei (which drains Lake Baikal via the Angara River) Lena, and Kolyma Rivers. It is also found in Kazakhstan and China in the Irtysh River and Wong Shek Pier, a major tributary of the Ob. The species epithet honors the German Russian biologist Karl Ernst von Baer. Taxonomy The Siberian sturgeon has previously been divided into two subspecies. However, recent studies suggest they may be monotypic, forming continuous genetically connected populations throughout their vast range.Ruban, G.I. (1999). he Siberian Sturgeon ''Acipenser baerii'' Brandt (Structure and Ecology of the Species) Moscow. GEOS publishers. Pp. 235 (in Russian). The previous nominate taxon (''A. b. baerii'') accounts for 80% of all Siberian sturgeon and resides in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Friedrich Von Brandt
Johann Friedrich von Brandt (25 May 1802 – 15 July 1879) was a German-Russian natural history, naturalist, who worked mostly in Russia. Brandt was born in Jüterbog and educated at a Gymnasium (school), gymnasium in Wittenberg and the Humboldt University of Berlin, University of Berlin. In 1831 he emigrated to Russia, and soon was appointed director of the Zoological Museum of the St Petersburg Academy of Sciences. Brandt encouraged the collection of native animals, many of which were not represented in the museum. Many specimens began to arrive from the expeditions of Nikolai Alekseevich Severtzov, Severtzov, Nikolai Przhevalsky, Przhevalsky, Aleksandr Fyodorovich Middendorf, Middendorff, Leopold von Schrenck, Schrenck and Gustav Radde. He described several birds collected by Russian explorers off the Pacific Coast of North America, including Brandt's cormorant, red-legged kittiwake and spectacled eider. As a paleontologist, Brandt ranks among the best. He was also an entomo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wong Shek Pier
Wong Shek Pier () is a public pier on the shore of Long Harbour () in the north-east of Hong Kong's New Territories. It is situated in the Wong Shek () area of the Sai Kung Peninsula. Administratively it is in Tai Po District. The pier serves kai-to ferry routes to remote settlements on the peninsular and its outlying islands, such as Tap Mun (), Wan Tsai () and Chek Keng (), and provides their principal connection to the rest of Hong Kong. It was reconstructed in 2006. Transportation Kowloon Motor Bus * Route #94 - from Sai Kung Bus Terminus * Route #96R - from Diamond Hill MTR Station * Route #289R - from Sha Tin Central (New Town Plaza) Bus Terminus Note: All routes ending in “R” run only on weekends and public holidays. Kai-to * Ma Liu Shui - Sham Chung - Lai Chi Chong - Tap Mun - Ko Lau Wan - Chek Keng - Wong Shek Pier * Wong Shek Pier - Chek Keng - Tap Mun * Wong Shek Pier - Wan Tsai Wan Tsai () is a peninsula at the northern extremity of the north-wester ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poaching
Poaching has been defined as the illegal hunting or capturing of wild animals, usually associated with land use rights. Poaching was once performed by impoverished peasants for subsistence purposes and to supplement meager diets. It was set against the hunting privileges of nobility and territorial rulers. Since the 1980s, the term "poaching" has also been used to refer to the illegal harvesting of wild plant species. In agricultural terms, the term 'poaching' is also applied to the loss of soils or grass by the damaging action of feet of livestock, which can affect availability of productive land, water pollution through increased runoff and welfare issues for cattle. Stealing livestock as in cattle raiding classifies as theft, not as poaching. The United Nations' Sustainable Development Goal 15 enshrines the sustainable use of all wildlife. It targets the taking of action on dealing with poaching and trafficking of protected species of flora and fauna to ensure their avail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habitat Degradation
Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby reducing biodiversity and species abundance. Habitat destruction is the leading cause of biodiversity loss. Fragmentation and loss of habitat have become one of the most important topics of research in ecology as they are major threats to the survival of endangered species. Activities such as harvesting natural resources, industrial production and urbanization are human contributions to habitat destruction. Pressure from agriculture is the principal human cause. Some others include mining, logging, trawling, and urban sprawl. Habitat destruction is currently considered the primary cause of species extinction worldwide. Environmental factors can contribute to habitat destruction more indirectly. Geological processes, climate change, intro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habitat Loss
Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby reducing biodiversity and species abundance. Habitat destruction is the leading cause of biodiversity loss. Fragmentation and loss of habitat have become one of the most important topics of research in ecology as they are major threats to the survival of endangered species. Activities such as harvesting natural resources, industrial production and urbanization are human contributions to habitat destruction. Pressure from agriculture is the principal human cause. Some others include mining, logging, trawling, and urban sprawl. Habitat destruction is currently considered the primary cause of species extinction worldwide. Environmental factors can contribute to habitat destruction more indirectly. Geological processes, climate change, introdu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Main Stem
In hydrology, a mainstem (or trunk) is "the primary downstream segment of a river, as contrasted to its tributaries". Water enters the mainstem from the river's drainage basin, the land area through which the mainstem and its tributaries flow.. A drainage basin may also be referred to as a ''watershed'' or ''catchment''. Hydrological classification systems assign numbers to tributaries and mainstems within a drainage basin. In the Strahler number, a modification of a system devised by Robert E. Horton in 1945, channels with no tributaries are called "first-order" streams. When two first-order streams meet, they are said to form a second-order stream; when two second-order streams meet, they form a third-order stream, and so on. In the Horton system, the entire mainstem of a drainage basin was assigned the highest number in that basin. However, in the Strahler system, adopted in 1957, only that part of the mainstem below the tributary of the next highest rank gets the highest num ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenga River
The Selenga or Selenge ( ; bua, Сэлэнгэ гол / Сэлэнгэ мүрэн, translit=Selenge gol / Selenge müren; russian: Селенга́, ) is a major river in Mongolia and Buryatia, Russia. Originating from its headwater tributaries, the Ider and the Delger mörön, it flows for before draining into Lake Baikal. The Selenga therefore makes up the most distant headwaters of the Yenisey- Angara river system. Carrying of water into Lake Baikal, it makes up almost half of the riverine inflow into the lake, and forms a wide delta of when it reaches the lake. Periodic annual floods are a feature of the Selenga River. The floods can be classified as “ordinary”, “large” or “catastrophic” based on the degree of impact. Of the twenty-six documented floods that occurred between 1730 and 1900, three were “catastrophic”. The three “catastrophic” floods were the floods of 1830, 1869 and 1897. The Selenga River basin is a semi-arid region that is in are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baikal Sturgeon
The Siberian sturgeon (''Acipenser baerii'') is a species of sturgeon in the family Acipenseridae. It is most present in all of the major Siberian river basins that drain northward into the Kara, Laptev and East Siberian Seas, including the Ob, Yenisei (which drains Lake Baikal via the Angara River) Lena, and Kolyma Rivers. It is also found in Kazakhstan and China in the Irtysh River and Wong Shek Pier, a major tributary of the Ob. The species epithet honors the German Russian biologist Karl Ernst von Baer. Taxonomy The Siberian sturgeon has previously been divided into two subspecies. However, recent studies suggest they may be monotypic, forming continuous genetically connected populations throughout their vast range.Ruban, G.I. (1999). he Siberian Sturgeon ''Acipenser baerii'' Brandt (Structure and Ecology of the Species) Moscow. GEOS publishers. Pp. 235 (in Russian). The previous nominate taxon (''A. b. baerii'') accounts for 80% of all Siberian sturgeon and resides in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spawn (biology)
Spawn is the Egg cell, eggs and Spermatozoa, sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquatic mammals and marine reptile, reptiles, reproduce through the process of spawning. Spawn consists of the reproductive cells (gametes) of many aquatic animals, some of which will become fertilized and produce offspring. The process of spawning typically involves females releasing Ovum, ova (unfertilized eggs) into the water, often in large quantities, while males simultaneously or sequentially release spermatozoa (milt) to fertilize the eggs. Most fish reproduce by spawning, as do most other aquatic animals, including crustaceans such as crabs and shrimps, molluscs such as oysters and squid, echinoderms such as sea urchins and sea cucumbers, amphibians such as frogs and newts, aquatic insects such as mayflies and mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anoxic Waters
Anoxic waters are areas of sea water, fresh water, or groundwater that are depleted of dissolved oxygen. The US Geological Survey defines anoxic groundwater as those with dissolved oxygen concentration of less than 0.5 milligrams per litre. Anoxic waters can be contrasted with hypoxic waters, which are low (but not lacking) in dissolved oxygen. This condition is generally found in areas that have restricted water exchange. In most cases, oxygen is prevented from reaching the deeper levels by a physical barrier, as well as by a pronounced density stratification, in which, for instance, heavier hypersaline waters rest at the bottom of a basin. Anoxic conditions will occur if the rate of oxidation of organic matter by bacteria is greater than the supply of dissolved oxygen. Anoxic waters are a natural phenomenon, and have occurred throughout geological history. The Permian–Triassic extinction event, a mass extinction of species from the world's oceans, may have resulted from w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxon
In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping. Initial attempts at classifying and ordering organisms (plants and animals) were set forth in Carl Linnaeus's Linnaean taxonomy, system in ''Systema Naturae'', 10th edition (1758), as well as an unpublished work by Bernard de Jussieu, Bernard and Antoine Laurent de Jussieu. The idea of a unit-based system of biological classification was first mad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monotypic
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispecific" or "monospecific" is sometimes preferred. In botanical nomenclature, a monotypic genus is a genus in the special case where a genus and a single species are simultaneously described. In contrast, an oligotypic taxon contains more than one but only a very few subordinate taxa. Examples Just as the term ''monotypic'' is used to describe a taxon including only one subdivision, the contained taxon can also be referred to as monotypic within the higher-level taxon, e.g. a genus monotypic within a family. Some examples of monotypic groups are: Plants * In the order Amborellales, there is only one family, Amborellaceae and there is only one genus, '' Amborella'', and in this genus there is only one species, namely ''Amborella trichopoda. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
