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Environmental Impacts Of Beavers
The beaver is a keystone species, increasing biodiversity in its territory through creation of ponds and wetlands. As wetlands are formed and riparian habitats enlarged, aquatic plants colonize newly available watery habitat. Insect, invertebrate, fish, mammal, and bird diversities are also expanded. Effects of beaver recolonization on native and non-native species in streams where they have been historically absent, particularly dryland streams, is not well-researched. Effects on stream flows and water quality Beaver ponds increase stream flows in seasonally dry streams by storing run-off in the rainy season, which raises groundwater tables via percolation from beaver ponds. In a recent study using 12 serial aerial photo mosaics from 1948 to 2002, the impact of the return of beavers on openwater area in east-central Alberta, Canada, found that the mammals were associated with a 9-fold increase in openwater area. Beavers returned to the area in 1954 after a long absence since thei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beaver Dam
A beaver dam or beaver impoundment is a dam built by beavers to create a pond which protects against predators such as coyotes, wolves and bears, and holds their food during winter. These structures modify the natural environment in such a way that the overall ecosystem builds upon the change, making beavers a keystone species and ecosystem engineers. They build prolifically at night, carrying mud and stones with their forepaws and timber between their teeth. Construction A minimum water level of is required to keep the underwater entrance to beaver lodges from being blocked by ice during the winter. In lakes, rivers and large streams with deep enough water, beavers may not even need to build dams, and instead simply live in bank burrows and lodges. If the water is not deep enough to keep beavers safe from predators and their lodge entrances ice-free, beavers build dams.Beavers start construction by diverting the stream to lessen the water's flow pressure. Branches and logs are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and silt can be carried in suspension in river water and on reaching the sea bed deposited by sedimentation; if buried, they may eventually become sandstone and siltstone (sedimentary rocks) through lithification. Sediments are most often transported by water ( fluvial processes), but also wind ( aeolian processes) and glaciers. Beach sands and river channel deposits are examples of fluvial transport and deposition, though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of aeolian transport and deposition. Glacial moraine deposits and till are ice-transported sediments. Classification Sediment can be classified based on its grain size, grain sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merganser
''Mergus'' is the genus of the typical mergansers , fish-eating ducks in the subfamily Anatinae. The genus name is a Latin word used by Pliny the Elder and other Roman authors to refer to an unspecified waterbird. The common merganser (''Mergus merganser'') and red-breasted merganser (''M. serrator'') have broad ranges in the northern hemisphere. The Brazilian merganser (''M. octosetaceus'') is a South American duck, and one of the six most threatened waterfowl in the world, with possibly fewer than 250 birds in the wild. The scaly-sided merganser or "Chinese merganser" (''M. squamatus'') is an endangered species. It lives in temperate East Asia, breeding in the north and wintering in the south. The hooded merganser (''Lophodytes cucullatus'', formerly known as ''Mergus cucullatus'') is not of this genus but is closely related. The other "aberrant" merganser, the smew (''Mergellus albellus''), is phylogenetically closer to goldeneyes (''Bucephala''). Although they a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Goldeneye (duck)
''Bucephala'' is a genus of diving ducks found in the Northern Hemisphere. Taxonomy The genus ''Bucephala'' was introduced in 1858 by American naturalist Spencer Baird with the bufflehead as the type species. The genus name is derived from Ancient Greek ''boukephalos'', meaning "bullheaded", from ''bous'' "bull", and ''kephale'', "head", a reference to the crest of the bufflehead making its head look large. The bufflehead was formerly treated as the only member of the genus (sometimes unnecessarily changed to ''Charitonetta'') while the goldeneyes were incorrectly placed in ''Clangula'' (as ''Clangula americana''), the genus of the long-tailed duck, which at that time was placed in '' Harelda''.Report of the National conference on utilization of forest products. New national museum, Washington, DC, November 19 and 20, 1924. Issue 13. US Govt. print. off. 1925. It may yet be correct to recognise two genera, as the bufflehead and the two goldeneyes are well diverged. In this case ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wood Duck
The wood duck or Carolina duck (''Aix sponsa'') is a species of perching duck found in North America. The drake wood duck is one of the most colorful North American waterfowl. Description The wood duck is a medium-sized perching duck. A typical adult is from ( or 1.5 feet max.) In length with a wingspan of between . The wood duck's weight ranges from 454-862 g (16.0-30.4 oz). This is about three-quarters of the length of an adult mallard. It shares its genus with the Asian Mandarin duck (''Aix galericulata''). The adult male has stunning multicolored iridescent plumage and red eyes, with a distinctive white flare down the neck. The female, less colorful, has a white eye-ring and a whitish throat. Both adults have crested heads. The male's call is a rising whistle, ''jeeeeee''; the females utter a drawn-out, rising squeal, ''do weep do weep'', when flushed, and a sharp ''cr-r-ek, cr-e-ek'' for an alarm call. Behavior Their breeding habitat is wooded swamps, shallo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tit (bird)
The tits, chickadees, and titmice constitute the Paridae, a large family of small passerine birds which occur mainly in the Northern Hemisphere and Africa. Most were formerly classified in the genus ''Parus''. Members of this family are commonly referred to as "tits" throughout much of the English speaking world, but North American species are called either "chickadees" (onomatopoeic, derived from their distinctive "chick-a dee dee dee" alarm call) or "titmice". The name titmouse is recorded from the 14th century, composed of the Old English name for the bird, ''mase'' (Proto-Germanic ''*maison'', Dutch ''mees'', German ''Meise''), and tit, denoting something small. The former spelling, "titmose", was influenced by ''mouse'' in the 16th century. Emigrants to New Zealand presumably identified some of the superficially similar birds of the genus ''Petroica'' of the family Petroicidae, the Australian robins, as members of the tit family, giving them the title tomtit, although, in fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tree Swallow
The tree swallow (''Tachycineta bicolor'') is a migratory bird of the family Hirundinidae. Found in the Americas, the tree swallow was first described in 1807 by French ornithologist Louis Vieillot as ''Hirundo bicolor''. It has since been moved to its current genus, ''Tachycineta'', within which its phylogenetic placement is debated. The tree swallow has glossy blue-green , with the exception of the blackish wings and tail, and white . The bill is black, the eyes dark brown, and the legs and feet pale brown. The female is generally duller than the male, and the first-year female has mostly brown upperparts, with some blue feathers. Juveniles have brown upperparts, and a grey-brown-washed breast. The tree swallow breeds in the US and Canada. It winters along southern US coasts south, along the Gulf Coast, to Panama and the northwestern coast of South America, and in the West Indies. The tree swallow nests either in isolated pairs or loose groups, in both natural and artificial c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Empidonax
The genus ''Empidonax'' is a group of small insect-eating passerine birds in the tyrant flycatcher family, the Tyrannidae. The genus name ''Empidonax'' is from Ancient Greek ''empis'', " gnat", and ''anax'', "master". Most of these birds are very similar in plumage: olive on the upper parts with light underparts, eye rings and wing bars. In the nesting season they may be distinguished by range, habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ... and call; in other situations, particularly on migration and in winter, it may not be possible to be sure of specific identification. ''Empidonax'' flycatchers often flick their wings and tails rapidly. Euler's flycatcher, ''Lathrotriccus euleri'' and gray-breasted flycatcher, ''Lathrotriccus griseipectus'' were formerly plac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coppicing
Coppicing is a traditional method of woodland management which exploits the capacity of many species of trees to put out new shoots from their stump or roots if cut down. In a coppiced wood, which is called a copse, young tree stems are repeatedly cut down to near ground level, resulting in a stool. New growth emerges, and after a number of years, the coppiced tree is harvested, and the cycle begins anew. Pollarding is a similar process carried out at a higher level on the tree in order to prevent grazing animals from eating new shoots. ''Daisugi'' (台杉, where ''sugi'' refers to Japanese cedar), is a similar Japanese technique. Many silviculture practices involve cutting and regrowth; coppicing has been of significance in many parts of lowland temperate Europe. The widespread and long-term practice of coppicing as a landscape-scale industry is something that remains of special importance in southern England. Many of the English language terms referenced in this article are pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canada Goose
The Canada goose (''Branta canadensis''), or Canadian goose, is a large wild goose with a black head and neck, white cheeks, white under its chin, and a brown body. It is native to the arctic and temperate regions of North America, and it is occasionally found during bird migration, migration across the Atlantic in northern Europe. It has been introduced to the United Kingdom, Ireland, Finland, Sweden, Denmark, New Zealand, Japan, Chile, Argentina, and the Falkland Islands. Like most geese, the Canada goose is primarily herbivorous and normally migratory; often found on or close to fresh water, the Canada goose is also common in Brackish water, brackish marshes, estuaries, and lagoons. Extremely adept at urban wildlife, living in human-altered areas, Canada geese have established breeding colonies in urban and cultivated habitats, which provide food and few natural predators. The success of this common park species has led to its often being considered a pest (organism), pest s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trumpeter Swan
The trumpeter swan (''Cygnus buccinator'') is a species of swan found in North America. The heaviest living bird native to North America, it is also the largest extant species of waterfowl, with a wingspan of 185 to 250 cm (6 ft 2 in to 8 ft 2 in). It is the American counterpart and a close relative of the whooper swan (''Cygnus cygnus'') of Eurasia, and even has been considered the same species by some authorities. By 1933, fewer than 70 wild trumpeters were known to exist, and extinction seemed imminent, until aerial surveys discovered a Pacific population of several thousand trumpeters around Alaska's Copper River. Careful reintroductions by wildlife agencies and the Trumpeter Swan Society gradually restored the North American wild population to over 46,000 birds by 2010. Description The trumpeter swan is the largest extant species of waterfowl, and both the heaviest and longest native bird of North America. Adults usually measure long, though large males can exceed in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canada Geese Nesting On Beaver Lodge, Crawford County, PA 1960
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by total area. Its southern and western border with the United States, stretching , is the world's longest binational land border. Canada's capital is Ottawa, and its three largest metropolitan areas are Toronto, Montreal, and Vancouver. Indigenous peoples have continuously inhabited what is now Canada for thousands of years. Beginning in the 16th century, British and French expeditions explored and later settled along the Atlantic coast. As a consequence of various armed conflicts, France ceded nearly all of its colonies in North America in 1763. In 1867, with the union of three British North American colonies through Confederation, Canada was formed as a federal dominion of four provinces. This began an accretion of provinces and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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