No import permit is necessary for these species under CITES, although some Parties do require import permits as part of their stricter domestic measures.

In practice, control measures focus on mosquito species that are vectors of human or livestock disease, or that are seriously irritant pests.

In the latter case, one species measures all six orthogonal components of polarization, and is believed to have optimal polarization vision.

Such ex-situ conservation measures may be followed by re-introduction of the species into the wild.

Biosecurity is a set of preventive measures designed to reduce the risk of transmission of infectious diseases, quarantined pests, invasive alien species, living modified organisms.

It is also naturalised throughout Europe, Argentina and Chile ( called Pino Oregón ), and in New Zealand sometimes to the extent of becoming an invasive species ( termed a wilding conifer ) subject to control measures.

The government has taken measures to halt or slow down the cultivation of opium poppies and cannabis by spraying crops with herbicides, which threaten the populations of many different species.

A small number of willow species were widely planted in Australia, notably as erosion-control measures along watercourses.

In the case of exotic species, the habitat can be improved significantly if the impact is mitigated by measures such as leaving blocks of native species in the plantation, or retaining corridors of natural forest.

The A. anhinga species is a large bird and measures approximately in length, with a range of, with a wingspan.

The species measures in length with a wingspan of.

This species measures around in body length, with a wingspan of.

The smallest icterid species is the Orchard Oriole, in which the female averaging 15 cm in length ( 6 in ) and 18 grams ( 0. 6 oz ) in weight, while the largest is the Amazonian Oropendola, the male of which measures 52 cm ( 19 in ) and weighs about 550 grams ( 1. 2 lbs ).

Several steps should be taken to develop drought-resistant farming systems even in " normal " years, including both policy and management actions: 1 ) improving water conservation and storage measures, 2 ) providing incentives for selection of drought-tolerant crop species, 3 ) using reduced-volume irrigation systems, 4 ) managing crops to reduce water loss, or 5 ) not planting at all.

Similarly, an ecosystem may experience a dramatic shift if a keystone species is removed, even though that species was a small part of the ecosystem by measures of biomass or productivity.

Cloning was not implemented for conservation as the Department of Environment and Natural Resource argued that such measures would diminish the genetic diversity of the species.

Under the 1995 UN Agreement on the Conservation and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks ( UNFSA ), coastal and fishing states are specifically required to adopt measures to conserve listed species, but little progress is visible on the oceanic whitetip.

However, many residents have objected to restrictions on land cultivation and improvement brought about by the measures in place to protect the Iriomote cat and other species on the island.

This species measures long, with a wingspan up to and a body mass of.

On average, this species measures from long, not counting a tail length of.

Sappi is also involved in wildlife conservation measures, such as its involvement in the Sappi WWF TreeRoutes Partnership which has set up community based ecotourism venues such as the new Karkloof Conservation Center which helps protect all three of South Africa's crane species.

This species of " phantom midge " ( so called because the larvae are transparent and very difficult to see ) measures less than 1 / 4 " long and resembles a tiny mosquito, but is non-biting.

Member States of the European Union are obliged by virtue of Council Directive 2009 / 147 / EC on the conservation of wild birds ( popularly called the Birds Directive ) to take the requisite measures for the protection of the red grouse ; but as it is a species to which Annex II of the Directive applies, Article 7 permits hunting under national law, provided population levels are not threatened as a result.

Tadpoles do not have true teeth but, in most species, the jaws have long, parallel rows of small keratinized structures called keradonts surrounded by a horny beak.

Many species have an erect woody stem which is covered with persistent dried leaves unless there have been fires, topped by a crown of long thin leaves.

Abalone have long been a valuable food source for humans in every area of the world where a species is abundant.

For higher values, the surface diffusion of deposited atomic species would allow for the formation of crystallites with long range atomic order.

Many species undertake long distance annual migrations, and many more perform shorter irregular movements.

No modern species should be described as more " primitive " than others, strictly speaking, since each has an equally long evolutionary history — but the brains of modern hagfishes, lampreys, sharks, amphibians, reptiles, and mammals show a gradient of size and complexity that roughly follows the evolutionary sequence.

Chondrichthyes also lack ribs, so if they leave water, the larger species ' own body weight would crush their internal organs long before they would suffocate.

One factor was product of aridification, others groups responded to favorable climatic periods and expanded across the available habitat, occur as opportunistic species across wide distribution other groups diverged in long time isolated areas.

The United States of America, a signatory who has not yet ratified the treaty, has produced one of the most thorough implementation programs through species Recovery Programs and other mechanisms long in place in the USA for species conservation.

Many species of cactus have long, sharp spine ( botany ) | spines, like this Opuntia.

The fish community of this lake has remained stable over a long period until a number of introduced species | introductions in the 1970s restructured its food web.

The nature of interaction between early humans and these sister species has been a long standing source of controversy, the question being whether humans replaced these earlier species or whether they were in fact similar enough to interbreed, in which case these earlier populations may have contributed genetic material to modern humans.

Most species have a rich mane of long hair running from the withers or from the head.

The limitation of hydroponics is that only certain species of plants can survive for so long in water before they become waterlogged.

They have thick, silky fur, which can be long or short, colored black, grey, honey, white, brown, yellow, red, or a mix, depending on the species.

The species of genus Phodopus are the smallest, with bodies long ; the largest is the European hamster ( Cricetus cricetus ), measuring up to long, not including a short tail of up to.

Like the other Falco species, they have long wings as well as a distinctive long tail.

This includes one of only two known cyprinid species flocks ( the other, from Lake Lanao in the Philippines, has been decimated by introduced species ), which consists of fifteen relatively large, up to long, Labeobarbus barbs.

The disruption of the river's natural flow, run-off from agriculture, and the introduction of pest species like the European Carp has led to serious environmental damage along the river's length and to concerns that the river will be unusably salty in the medium to long term — a serious problem given that the Murray supplies 40 % of Adelaide's domestic water.

A mammoth is any species of the extinct genus Mammuthus, proboscideans commonly equipped with long, curved tusks and, in northern species, a covering of long hair.