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Euastacus Reductus
''Euastacus'' is a genus of freshwater crayfish known as "spiny crayfish". They are found in the south-east of the Australian mainland, along with another genus of crayfish, ''Cherax''. Both genera are members of the family Parastacidae, a family of freshwater crayfish restricted to the Southern Hemisphere. ''Euastacus'' crayfish are distinguished from the smooth-shelled ''Cherax'' species by the short robust spikes on their claws and carapace, and frequently, their larger size. Many ''Euastacus'' species grow to a relatively large size, with the Murray River crayfish (''Euastacus armatus'') being the second largest freshwater crayfish species in the world. (The largest freshwater crayfish in the world is the Tasmanian giant freshwater crayfish (''Astacopsis gouldi''), found on the Australian island of Tasmania, and the genus ''Astacopsis'' is now known to be a very closely related sister genus to ''Euastacus''.) The genera ''Cherax'' and ''Euastacus'' continue a trend presen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ellen Clark
Ellen Clark (1915–1988) was an Australian carcinologist and naturalist, whose work focused on crustaceans and ants Clark studied, named, described and published many of the Australian freshwater crayfish species. By 1939, she was reported to have identified more than half the known species of Australian crayfish. She conducted research about blood groups in crustaceans and made a significant contribution to the study of crayfish genera. She was the first woman to publish in the ''Memoirs of the National Museum of Victoria''. Ellen Clark's crayfish, ''Euastacus clarkae'', was named after Clark in recognition of her pioneering parastacid studies. Clark's work has had a lasting legacy and is still being debated in scientific papers. References Australian scientists 1915 births 1988 deaths Women naturalists 20th-century Australian women {{Australia-scientist-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drainage Basin
A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, the '' drainage divide'', made up of a succession of elevated features, such as ridges and hills. A basin may consist of smaller basins that merge at river confluences, forming a hierarchical pattern. Other terms for a drainage basin are catchment area, catchment basin, drainage area, river basin, water basin, and impluvium. In North America, they are commonly called a watershed, though in other English-speaking places, "watershed" is used only in its original sense, that of a drainage divide. In a closed drainage basin, or endorheic basin, the water converges to a single point inside the basin, known as a sink, which may be a permanent lake, a dry lake, or a point where surface water is lost underground. Drainage basins are similar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euastacus Australasiensis
''Euastacus'' is a genus of freshwater crayfish known as "spiny crayfish". They are found in the south-east of the Australian mainland, along with another genus of crayfish, ''Cherax''. Both genera are members of the family Parastacidae, a family of freshwater crayfish restricted to the Southern Hemisphere. ''Euastacus'' crayfish are distinguished from the smooth-shelled ''Cherax'' species by the short robust spikes on their claws and carapace, and frequently, their larger size. Many ''Euastacus'' species grow to a relatively large size, with the Murray River crayfish (''Euastacus armatus'') being the second largest freshwater crayfish species in the world. (The largest freshwater crayfish in the world is the Tasmanian giant freshwater crayfish (''Astacopsis gouldi''), found on the Australian island of Tasmania, and the genus ''Astacopsis'' is now known to be a very closely related sister genus to ''Euastacus''.) The genera ''Cherax'' and ''Euastacus'' continue a trend presen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Status Iucn DD Icon
Status (Latin plural: ''statūs''), is a state, condition, or situation, and may refer to: * Status (law) ** City status ** Legal status, in law ** Political status, in international law ** Small entity status, in patent law ** Status conference ** Status crime * Marital status * Observer status, in international organizations * Senior status * Social status, in sociology ** Achieved status ** Ascribed status ** Master status ** Socioeconomic status ** Sociometric status ** Status attainment ** Status offense ** Status shift * Status brand, in marketing * Status constructus, a noun form * Status match, in frequent-flyer loyalty programs * Status quo * Status symbol Arts, entertainment, and media * ''Status'', a magazine edited by Igor Cassini * Recurring status, in acting * Status effect, in gaming Computing * Exit status, in computer science * Process states (Process Status) * Status bar, in user interface design * Status message (instant messaging) * Status register, in co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Deficient
A data deficient (DD) species is one which has been categorized by the International Union for Conservation of Nature (IUCN) as offering insufficient information for a proper assessment of conservation status to be made. This does not necessarily indicate that the species has not been extensively studied; but it does indicate that little or no information is available on the abundance and distribution of the species. The IUCN recommends that care be taken to avoid classing species as "data deficient" when the absence of records may indicate dangerously low abundance: "If the range of a taxon is suspected to be relatively circumscribed, if a considerable period of time has elapsed since the last record of the taxon, threatened status may well be justified""The Categories," in IUCN (1983). (see also precautionary principle). See also * IUCN Red List data deficient species * List of data deficient amphibians * IUCN Red List data deficient species (Annelida) * List of data deficien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Least Concern
A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. They do not qualify as threatened, near threatened, or (before 2001) conservation dependent. Species cannot be assigned the "Least Concern" category unless they have had their population status evaluated. That is, adequate information is needed to make a direct, or indirect, assessment of its risk of extinction based on its distribution or population status. Evaluation Since 2001 the category has had the abbreviation "LC", following the IUCN 2001 Categories & Criteria (version 3.1). Before 2001 "least concern" was a subcategory of the "Lower Risk" category and assigned the code "LR/lc" or lc. Around 20% of least concern taxa (3261 of 15636) in the IUCN database still use the code "LR/lc", which indicates they have not been re-evaluate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Near Threatened
A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify for the threatened status. The IUCN notes the importance of re-evaluating near-threatened taxon at appropriate intervals. The rationale used for near-threatened taxa usually includes the criteria of vulnerable which are plausible or nearly met, such as reduction in numbers or range. Near-threatened species evaluated from 2001 onwards may also be ones which are dependent on conservation efforts to prevent their becoming threatened, whereas before this conservation-dependent species were given a separate category ("Conservation Dependent"). Additionally, the 402 conservation-dependent taxa may also be considered near-threatened. IUCN Categories and Criteria version 2.3 Before 2001, the IUCN used the version 2.3 Categories and Criteria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vulnerable Species
A vulnerable species is a species which has been Conservation status, categorized by the International Union for Conservation of Nature as being threatened species, threatened with extinction unless the circumstances that are threatened species, threatening its survival and reproduction improve. Vulnerability is mainly caused by habitat loss or destruction of the species' home. Vulnerable habitat or species are monitored and can become increasingly threatened. Some species listed as "vulnerable" may be common in captivity (animal), captivity, an example being the military macaw. There are currently 5196 animals and 6789 plants classified as Vulnerable, compared with 1998 levels of 2815 and 3222, respectively. Practices such as cryoconservation of animal genetic resources have been enforced in efforts to conserve vulnerable breeds of livestock specifically. Criteria The International Union for Conservation of Nature uses several criteria to enter species in this category. A tax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endangered Species
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and invasive species. The International Union for Conservation of Nature (IUCN) Red List lists the global conservation status of many species, and various other agencies assess the status of species within particular areas. Many nations have laws that protect conservation-reliant species which, for example, forbid hunting, restrict land development, or create protected areas. Some endangered species are the target of extensive conservation efforts such as captive breeding and habitat restoration. Human activity is a significant cause in causing some species to become endangered. Conservation status The conservation status of a species indicates the likelihood that it will become extinct. Multiple factors are considered when assessing the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IUCN Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biological species. It uses a set of precise criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world. With its strong scientific base, the IUCN Red List is recognized as the most authoritative guide to the status of biological diversity. A series of Regional Red Lists are produced by countries or organizations, which assess the risk of extinction to species within a political management unit. The aim of the IUCN Red List is to convey the urgency of conservation issues to the public and policy makers, as well as help the international community to reduce species extinction. According to IUCN the formally stated goals of the Red List are to provi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
