|
Glacier Bear
The glacier bear (''Ursus americanus emmonsii''), sometimes referred to as the "blue bear", is a subspecies of American black bear with silver-blue or gray hair endemic from Southeast Alaska, to the extreme northwestern tip of British Columbia, and to the extreme southwest of the Yukon. The Tlingit name for the glacier bear is a reference to their size, elusiveness, and ability to visually blend into snowfields: "sik noon", which means "a bear that disappears". Little scientific knowledge exists of their total extent and the cause of their unique coloration. Most other black bears in southeast Alaska are listed under the subspecies ''Ursus americanus pugnax''.MacDonald, S.O. and Cook, J.A. (2007Mammals and amphibians of Southeast Alaska The Museum of Southwestern Biology, The University of New Mexico, Albuquerque, NM 87131-0001.Schoen, J and Peacock, L. (2007) "Black Bear" in J Schoen and E Dovichin (eds.The coastal forest and mountains ecoregion of southeastern Alaska and the Tong ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Black Bear
The American black bear (''Ursus americanus''), also called simply a black bear or sometimes a baribal, is a medium-sized bear endemic to North America. It is the continent's smallest and most widely distributed bear species. American black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but will leave forests in search of food, and are sometimes attracted to human communities due to the immediate availability of food. The International Union for Conservation of Nature (IUCN) lists the American black bear as a least-concern species, due to its widespread distribution and a large population estimated to be twice that of all other bear species combined. Along with the brown bear (''Ursus arctos''), it is one of only two modern bear species not considered by the IUCN to be globally threatened with extinction. Taxonomy and evolution Despite living in North America, American black bears are not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tongass National Forest
The Tongass National Forest () in Southeast Alaska is the largest U.S. National Forest at . Most of its area is temperate rain forest and is remote enough to be home to many species of endangered and rare flora and fauna. The Tongass, which is managed by the United States Forest Service, encompasses islands of the Alexander Archipelago, fjords and glaciers, and peaks of the Coast Mountains. An international border with Canada (British Columbia) runs along the crest of the Boundary Ranges of the Coast Mountains. The forest is administered from Forest Service offices in Ketchikan. There are local ranger district offices located in Craig, Hoonah, Juneau, Ketchikan, Petersburg, Sitka, Thorne Bay, Wrangell, and Yakutat. History The Alexander Archipelago Forest Reserve was established by Theodore Roosevelt in a presidential proclamation of 20 August 1902. Another presidential proclamation made by Roosevelt, on 10 September 1907, created the Tongass National Forest. On 1 July ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fauna Of Alaska
The wildlife of Alaska is both diverse and abundant. The Alaskan Peninsula provides an important habitat for fish, mammals, reptiles, and birds. At the top of the food chain are the bears. Alaska contains about 70% of the total North American brown bear population and the majority of the grizzly bears. as well as black bears and Kodiak bears. In winter, polar bears can be found in the Kuskokwim Delta, St. Matthew Island, and at the southernmost portion of St. Lawrence Island. There are also moose and caribou, bison, wolves and wolverines, foxes, otters and beavers. Fish species are extensive, including: salmon, graylings, char, rainbow and lake trout, northern pike, halibut, pollock, and burbot. The bird population consists of hundreds of species, including: bald eagles, owls, falcons, ravens, ducks, geese, swans, and the passerines. Sea lions, seals, sea otters, and migratory whales are often found close to shore and in offshore waters. The Alaskan waters are home to two speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Black Bears
The American black bear (''Ursus americanus''), also called simply a black bear or sometimes a baribal, is a medium-sized bear endemic to North America. It is the continent's smallest and most widely distributed bear species. American black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but will leave forests in search of food, and are sometimes attracted to human communities due to the immediate availability of food. The International Union for Conservation of Nature (IUCN) lists the American black bear as a least-concern species, due to its widespread distribution and a large population estimated to be twice that of all other bear species combined. Along with the brown bear (''Ursus arctos''), it is one of only two modern bear species not considered by the IUCN to be globally threatened with extinction. Taxonomy and evolution Despite living in North America, American black bears are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canadian Geographic
''Canadian Geographic'' is a magazine published by the Royal Canadian Geographical Society, (RCGS) based in Ottawa, Ontario. History and profile After the Society was founded in 1929, the magazine was established the next year in May 1930 under the name ''Canadian Geographical Journal''. The Society's objective was to produce a popular magazine primarily focusing on Canadian geography. The first editor was Charles Camsell, since 1915 a fellow of the British Royal Geographical Society, as well as a geologist who had been responsible for mapping large parts of Northern Ontario, Manitoba and the Yukon. Originally published out of Montreal, Quebec, the magazine is now headquartered in Ottawa, Ontario. The magazine adopted its current title in 1978. Typically the magazine contains articles on physical, historical, political and environmental geography, illustrated with photographs, illustrations and maps. Controversial subjects such as acid rain, clear-cut logging, vanishing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid (biology)
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents (such as in blending inheritance), but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are. Species are reproductively isolated by strong barriers to hybridisation, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization and others after it. Similar barriers exist in plants, with differences in flowering tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Flow
In population genetics, gene flow (also known as gene migration or geneflow and allele flow) is the transfer of genetic material from one population to another. If the rate of gene flow is high enough, then two populations will have equivalent allele frequencies and therefore can be considered a single effective population. It has been shown that it takes only "one migrant per generation" to prevent populations from diverging due to drift. Populations can diverge due to selection even when they are exchanging alleles, if the selection pressure is strong enough. Gene flow is an important mechanism for transferring genetic diversity among populations. Migrants change the distribution of genetic diversity among populations, by modifying allele frequencies (the proportion of members carrying a particular variant of a gene). High rates of gene flow can reduce the genetic differentiation between the two groups, increasing homogeneity. For this reason, gene flow has been thought to con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overharvesting
Overexploitation, also called overharvesting, refers to harvesting a renewable resource to the point of diminishing returns. Continued overexploitation can lead to the destruction of the resource, as it will be unable to replenish. The term applies to natural resources such as Aquifer, water aquifers, Pasture, grazing pastures and forests, wild medicinal plants, fish stocks and other wildlife. In ecology, overexploitation describes one of the five main activities threatening global biodiversity. Ecologists use the term to describe populations that are harvested at an unsustainable rate, given their natural rates of mortality and capacities for reproduction. This can result in extinction at the population level and even extinction of whole species. In conservation biology, the term is usually used in the context of human economic activity that involves the taking of biological resources, or organisms, in larger numbers than their populations can withstand. The term is also used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rubus Spectabilis
''Rubus spectabilis'', the salmonberry, is a species of bramble in the rose family Rosaceae, native to the west coast of North America from west-central Alaska to California, inland as far as Idaho. Like many other species in the genus ''Rubus'', the salmonberry plant bears edible fruit, typically yellow-orange or red in color, resembling raspberries in appearance. Description ''Rubus spectabilis'' is a deciduous, rhizomatous shrub growing to tall and 9 metres (30 feet) wide, with a moderate growth rate of 0.3–06 metres (12-24 inches) per year. 30-40% of the plant's biomass is underground. It has perennial (not biennial) woody stems that are covered with fine prickles, especially on new growth. The plant has golden or yellowish brown erect or arching stems (also known as "canes") that often form thickets, like many other brambles in the genus ''Rubus''. The leaves are alternate, trifoliate (with three leaflets), long and typically ovate in shape, with the terminal leaflet b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Omnivore
An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutrients and energy of the sources absorbed. Often, they have the ability to incorporate food sources such as algae, fungi, and bacteria into their diet. Omnivores come from diverse backgrounds that often independently evolved sophisticated consumption capabilities. For instance, dogs evolved from primarily carnivorous organisms ( Carnivora) while pigs evolved from primarily herbivorous organisms (Artiodactyla). Despite this, physical characteristics such as tooth morphology may be reliable indicators of diet in mammals, with such morphological adaptation having been observed in bears. The variety of different animals that are classified as omnivores can be placed into further sub-categories depending on their feeding behaviors. Frugivor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Understory
In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but above the forest floor. Only a small percentage of light penetrates the canopy so understory vegetation is generally shade-tolerant. The understory typically consists of trees stunted through lack of light, other small trees with low light requirements, saplings, shrubs, vines and undergrowth. Small trees such as holly and dogwood are understory specialists. In temperate deciduous forests, many understory plants start into growth earlier in the year than the canopy trees, to make use of the greater availability of light at that particular time of year. A gap in the canopy caused by the death of a tree stimulates the potential emergent trees into competitive growth as they grow upwards to fill the gap. These trees tend to have straight trunks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temperate Rainforest
Temperate rainforests are coniferous or broadleaf forests that occur in the temperate zone and receive heavy rain. Temperate rain forests occur in oceanic moist regions around the world: the Pacific temperate rain forests of North American Pacific Northwest as well as the Appalachian temperate rainforest of the Eastern U.S. Sun Belt; the Valdivian temperate rain forests of southwestern South America; the rain forests of New Zealand and southeastern Australia; northwest Europe (small pockets in Great Britain and larger areas in Ireland, southern Norway and northern Iberia); southern Japan; the Black Sea–Caspian Sea region from the southeasternmost coastal zone of the Bulgarian coast, through Turkey, to Georgia, and northern Iran. The moist conditions of temperate rain forests generally support an understory of mosses, ferns and some shrubs and berries. Temperate rain forests can be temperate coniferous forests or temperate broadleaf and mixed forests. Definition For temperat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
