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绿蟹：关于这种入侵物种你应该知道的事情
绿蟹是一种入侵性水生物种，分布于美国东海岸和西海岸。 这种螃蟹原产于从挪威到毛里塔尼亚的东北大西洋沿岸，在过去的 200 年里已经在世界各地传播，与货船和贸易商一起进入新的港口，并在几个不同的国家建立种群。
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绿蟹是一种有问题的入侵物种，因为它改变了它进入的不同海洋栖息地的功能和组织，包括潮间带岩石海岸、潮间带泥滩、沼泽和鳗草床。 这种螃蟹还能够减少生物多样性和改变食物网。 有证据表明，绿蟹减少了新英格兰本土蛤蜊的数量，并且还伤害了其他具有商业价值的双壳类动物，包括扇贝和铜蛤。
美国国会大厦暴力事件
The green crabno bra is an invasive aquatic species found on both the Eastern and Western coasts of the United States. Native to the northeast Atlantic aboard from Norway to Mauritania, this crab has made its way around the world over the last 200 years, traveling along with cargo ships and traders into new ports and establishing populations in veral different countries.
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The green crab is a problematic invasive species becau it alters the function and organization of the different marine habitats it enters, including intertidal rocky shores, intertidal mudflats, marshes, and eelgrass beds. This crab is also capable of reducing biodiversity and altering food webs. There is evidence that green crabs have reduced populations of native clams in New England, and also harmed other commercially important bivalves including the scallops and quahogs.
How to Identify a Green Crab
Adult green crabs have mottled shells, usually dark brown or green in color, that reach around 3 to 4 inches in width. They are sometimes misidentified as native species including juvenile Dungeness and helmet crabs, but can be distinguished primarily by a t of five triangular teeth, or spines, evenly spaced between the eyes and the widest part of the shell on either side.
As our climate changes, this species will continue expanding into new environments, being tolerant of a wide range of hot and cold temperatures, according to rearch publis
hed in the Journal of Experimental Biology.
How the Green Crab Became an Invasive Species
越剧小生化妆
Green crabs (Carcinus maenas) are also called European green crabs in Canada and the United States, while in the British Isles they're typically referred to as shore crabs or green shore crabs. They were first documented on the East Coast in the early 19th century, one of at least two genetically distinct lineages of green crabs independently introduced in North America. (The cond was introduced in the late 20th century). It is lik
ely that one of the lineagesrom warmer native waters, while the other was native to cooler, northern environments.
Both of the 谈论的英文lineages of green crab eventually made their way to eastern Canada and hybridized, creating a point of contact in Nova Scotia. In that location, scientists found that the mean high temperature at which cardiac function fails in adult crabs is consistently higher in southern populations, which are adapted to overall warmer a surface temperatures. This indicates that green crabs are highly adaptable and change genetically to accommodate different native and non-native aquatic environments.
Initial introductions of the green crab to the East Coast came from ships arriving in New England from European waters, likely releasing ballast water (water stored in a ship's hold to provide needed weight) carried from overas that contained the crabs or their larvae. It is also likely that green crabs arrived to new areas in packing materials as well as shipments of live afood.
The crab's West Coast introduction may have occurred via boxes of live fishing bait in Sa
n Francisco. Once the crabs enter the water, their tiny larvae disper widely and are almost impossible to detect and remove.
Problems Caud by the Green Crab水墨画的意思
The green crab has had a wide-reaching impact on the United States' coastal waters since its introduction. Significant loss to commercial fisheries and natural ecosystems have been documented in waters where the crab now resides, including decread populations of clams, scallops, quahogs, and other native crab species.
good jobThe crabs have a wide variety of food preferences, and their ability to out-compete native species for food resources, high reproductive capacity, and wide environmental tolerances lend them the capacity to fundamentally alter community structure in coastal ecosystems. In Canada, for example, the aggressive green crab has been dubbed the "cockroach of the a," and is known for completely mowing down eelgrass beds, a valuable ecosystem and food source for many species. There is also evidence of a cascading impact on broader fish communities where green crabs are prent.
Complicating any understanding of the full scope of the impact of the green crab has been the more recent arrival of Asian shore crabs, thought to be displacing green crabs in some East Coast aquatic environments and also threatening native crabs and other species in the region. More rearch is required to fully understand the impact of the different invasive species interacting in the same environments.
百度英语翻译Green crabs established along the East Coast long before invasion biology was a science, and the ability of their small eggs to be disperd through tidal currents means that even new populations are difficult to control. That said, there have been efforts to trap crabs in Washington state as well as eastern Canada, and catch rates of green crabs declined in areas where government officials attempted to limit the population. The types of mitigation efforts are likely to have more success in areas in which the crab is newly prent.
