Southeast Alaska, sometimes referred to as the Alaska Panhandle, is the southeastern portion of the U. S. state of Alaska, bordered to the east by the northern half of the Canadian province of British Columbia. The majority of Southeast Alaska's area is part of the Tongass National Forest, the United States' largest national forest. In many places, the international border runs along the crest of the Boundary Ranges of the Coast Mountains; the region is noted for mild rainy climate. The largest cities in the region are Juneau and Ketchikan. Southeast Alaska is the northern terminus of the Inside Passage, a protected waterway of convoluted passages between islands and fjords, beginning in Puget Sound in Washington state; this was an important travel corridor for Tlingit and Haida Native peoples, as well as gold-rush era steamships. In modern times it is an important route for Alaska Marine Highway ferries as well as cruise ships. Southeast Alaska has a land area of 35,138 square miles comprising seven entire boroughs and two census areas, in addition to the portion of the Yakutat Borough lying east of 141° West longitude.
Although it has only 6.14 percent of Alaska's land area, it is larger than the state of Maine, as large as the state of Indiana. The Southeast Alaskan coast is as long as the west coast of Canada; the 2010 census population of Southeast was 71,616 inhabitants, about 45 percent of whom were concentrated in the city of Juneau. Haines Borough Hoonah-Angoon Census Area Juneau Borough Ketchikan Gateway Borough Petersburg Borough Prince of Wales-Hyder Census Area Sitka Borough Skagway Borough Wrangell Borough Yakutat Borough It includes the Tongass National Forest, Glacier Bay National Park, Sitka National Historical Park, Alaska's Inside Passage, myriad large and small islands; the largest islands are, from North to South, Chichagof Island, Admiralty Island, Baranof Island, Kupreanof Island, Revillagigedo Island and Prince of Wales Island. Major bodies of water of Southeast Alaska include Glacier Bay, Lynn Canal, Icy Strait, Chatham Strait, Stephens Passage, Frederick Sound, Sumner Strait, Clarence Strait.
On August 20, 1902, President Theodore Roosevelt established the Alexander Archipelago Forest Reserve, which formed the heart of the Tongass National Forest that covers most of the region. Glacier Bay National Park and Preserve Klondike Gold Rush National Historical Park Sitka National Historical Park Wrangell-St. Elias National Park and Preserve Admiralty Island National Monument Misty Fjords National Monument Southeast Alaska is a temperate rain forest within the Pacific temperate rain forest zone, as classified by the World Wildlife Fund's ecoregion system, which extends from northern California to Prince William Sound; the most common tree species are western hemlock. Wildlife includes brown bears, black bears, the endemic Alexander Archipelago wolf, Sitka black-tailed deer, humpback whales, five species of salmon, bald eagles, harlequin ducks and marbled murrelets; the Ecological Atlas of Southeast Alaska, published by Audubon Alaska in 2016, offers an overview of the region's landscape, wildlife, human uses, climate change, more, synthesizing data from agencies and a variety of other sources.
Major cities are Juneau and Sitka. Other towns are Petersburg, Metlakatla, Hoonah, Kake, Klawock, Thorne Bay, Yakutat and Gustavus. There are many towns and villages with around 100 people, such as Baranof Warm Springs, Edna Bay, Elfin Cove, Excursion Inlet, Funter Bay, Meyers Chuck, Port Alexander, Port Frederick, Port Protection, Tenakee Springs; this region is home to the easternmost town in Alaska, Hyder. This area is the traditional homeland of the Tlingit, home of a historic settling of Haida as well as a modern settlement of Tsimshian; the region is connected to Seattle and the American Pacific Northwest economically and culturally. Major industries in Southeast Alaska include commercial tourism. Logging has been an important industry in the past, but has been declining with competition from other areas and the closure of the region's major pulp mills, its members include Alcan Forest Products and Viking Lumber, founded in Maine. Debates over whether to expand logging in the federally owned Tongass are not uncommon.
Mining remains important in the northern area with the Juneau mining district and Admiralty mining district hosting active mines as of 2015. Gold played an important part in the early history of the region. In the 2010s, mines begun to be explored and completed in neighboring British Columbia, upstream of important rivers such as the Unuk and the Stikine, which became known as the transboundary mining issue. In 2014, the Mount Polley Mine disaster focused attention on the issue, an agreement between Canada and Alaska was drafted in 2015; the proposed Kerr Sulphurets Mitchell exploration is upstream of the Unuk. Mines upstream of the Stikine include the Red Chris, owned by the same company as the Mount Polley mine; the border between the Canadian province of British Columbia and Alaska was the subject of the Alaska boundary dispute, where the United States and the United Kingdom and Brit
An introduced species is a species living outside its native distributional range, but which has arrived there by human activity, either deliberate or accidental. Non-native species can have various effects on the local ecosystem. Introduced species that become established and spread beyond the place of introduction are called invasive species; the impact of introduced species is variable. Some have a negative effect on a local ecosystem, while other introduced species may have no negative effect or only minor impact; some species have been introduced intentionally to combat pests. They are called biocontrols and may be regarded as beneficial as an alternative to pesticides in agriculture for example. In some instances the potential for being beneficial or detrimental in the long run remains unknown; the effects of introduced species on natural environments have gained much scrutiny from scientists, governments and others. The formal definition of an introduced species, from the United States Environmental Protection Agency, is A species, intentionally or inadvertently brought into a region or area.
Called an exotic or non-native species. There are many terms associated with introduced species that represent subsets of introduced species, the terminology associated with introduced species is now in flux for various reasons. Examples of these terms are acclimatized, adventive and immigrant species but those terms refer to a subset of introduced species; the term "invasive" is used to describe introduced species when the introduced species causes substantial damage to the area in which it was introduced. Subset descriptions: Acclimatized species: Introduced species that have changed physically and/or behaviorally in order to adjust to their new environment. Acclimatized species are not optimally adjusted to their new environment and may just be physically/behaviorally sufficient for the new environment. Adventive speciesNaturalized species: A naturalized plant species refers to a non-native plant that does not need human help to reproduce and maintain its population in an area that it is not native to.
General description of introduced species: In the broadest and most used sense, an introduced species is synonymous with non-native and therefore applies as well to most garden and farm organisms. However, some sources add to that basic definition "and are now reproducing in the wild", which removes from consideration as introduced species that were raised or grown in gardens or farms that do not survive without tending by people. With respect to plants, these latter are in this case defined as either ornamental or cultivated plants. Introduction of a species outside its native range is all, required to be qualified as an "introduced species" such that one can distinguish between introduced species that may not occur except in cultivation, under domestication or captivity whereas others become established outside their native range and reproduce without human assistance; such species might be termed "naturalized", "established", "wild non-native species". If they further spread beyond the place of introduction and cause damage to nearby species, they are called "invasive".
The transition from introduction, to establishment and to invasion has been described in the context of plants. Introduced species are "non-native" species. Invasive species are those introduced species that spreadwidely or and cause harm, be that to the environment, human health, other valued resources or the economy. There have been calls from scientists to consider a species "invasive" only in terms of their spread and reproduction rather than the harm they may cause. According to a practical definition, an invasive species is one, introduced and become a pest in its new location, spreading by natural means; the term is used to imply both a sense of actual or potential harm. For example, U. S. Executive Order 13112 defines "invasive species" as "an alien species whose introduction does or is to cause economic or environmental harm or harm to human health"; the biological definition of invasive species, on the other hand, makes no reference to the harm they may cause, only to the fact that they spread beyond the area of original introduction.
Although some argue that "invasive" is a loaded word and harm is difficult to define, the fact of the matter is that organisms have and continue to be introduced to areas in which they are not native, sometimes with but without much regard to the harm that could result. From a regulatory perspective, it is neither desirable nor practical to list as undesirable or outright ban all non-native species. Regulations require a definitional distinction between non-natives that are deemed onerous and all others. Introduced pest species that are listed as invasive, best fit the definition of an invasive species. Early detection and rapid response is the most effective strategy for regulating a pest species and reducing economic and environmental impacts of an introduction In Great Britain, the Wildlife and Countryside Act 1981 prevents the introduction of any animal not occurring in the wild or any of a list of both animals or plants introduced and proved to be invasive. By definition, a species is considered "introduced" when its transport into an area outside of its native range is human mediated.
Introductions by humans can be described as either accidental. Intentional introductions have been motivated by individuals or groups who either believe that the
Bermuda is a British Overseas Territory in the North Atlantic Ocean. It is 1,070 km east-southeast of Cape Hatteras, North Carolina; the capital city is Hamilton. Bermuda is self-governing, with its own constitution and its own government, which enacts local laws, while the United Kingdom retains responsibility for defence and foreign relations; as of July 2018, its population is the highest of the British overseas territories. Bermuda's two largest economic sectors are offshore insurance and reinsurance, tourism. Bermuda had one of the world's highest GDP per capita for most of the 20th century; the islands have a subtropical climate and lies in the hurricane belt and thus is prone to related severe weather. The first European known to have reached Bermuda was the Spanish sea captain Juan de Bermúdez in 1505, after whom the islands are named, he claimed the islands for the Spanish Empire. Unusually, Bermuda had no indigenous population at the time of its discovery, nor at the time of the initial British settlement a century later.
Bermúdez never landed on the islands, but made two visits to the archipelago, of which he created a recognisable map. Shipwrecked Portuguese mariners are now thought to have been responsible for the 1543 inscription on Portuguese Rock. Subsequent Spanish or other European parties are believed to have released pigs there, which had become feral and abundant on the island by the time European settlement began. In 1609, the English Virginia Company permanently settled Bermuda in the aftermath of a hurricane, when the crew and passengers of the Sea Venture steered the ship onto the surrounding reef to prevent its sinking landed ashore; the island was administered as an extension of Virginia by the Company until 1614. Its spin-off, the Somers Isles Company, took over in 1615 and managed the colony until 1684. At that time, the company's charter was revoked, the English Crown took over administration; the islands became a British colony following the 1707 unification of the parliaments of Scotland and England, which created the Kingdom of Great Britain.
After 1949, when Newfoundland became part of Canada, Bermuda became the oldest remaining British overseas territory. After the return of Hong Kong to China in 1997, Bermuda became the most populous remaining dependent territory, its first capital, St. George's, was established in 1612. Bermuda was discovered in 1505 by Spanish explorer Juan de Bermúdez, it is mentioned in Legatio Babylonica, published in 1511 by historian Pedro Mártir de Anglería, was included on Spanish charts of that year. Both Spanish and Portuguese ships used the islands as a replenishment spot to take on fresh meat and water. Legends arose of spirits and devils, now thought to have stemmed from the calls of raucous birds and the loud noise heard at night from wild hogs. Combined with the frequent storm-wracked conditions and the dangerous reefs, the archipelago became known as the Isle of Devils. Neither Spain nor Portugal attempted to settle it. For the next century, the island is believed to have been visited but not settled.
After the failure of the first two English colonies in Virginia, a more determined effort was initiated by King James I of England, who granted a Royal Charter to the Virginia Company. It established a colony at Jamestown, Virginia, in 1607. Two years a flotilla of seven ships left England under the Company's Admiral, Sir George Somers, the new Governor of Jamestown, Sir Thomas Gates, with several hundred settlers and supplies to relieve the colony of Jamestown. Somers had previous experience sailing with both Sir Francis Sir Walter Raleigh; the flotilla was broken up by a storm. As the flagship, Sea Venture, was taking on water, Somers drove it onto Bermuda's reef and gained the shores safely with smaller boats – all 150 passengers and a dog survived, they stayed ten months, building two small ships to sail to Jamestown. The group of islands were claimed for the English Crown, the charter of the Virginia Company was extended to include them. In 1610, all but three of the survivors of Sea Venture sailed on to Jamestown.
Among them was John Rolfe, whose wife and child died and were buried in Bermuda. In Jamestown he married Pocahontas, a daughter of the powerful Powhatan, leader of a large confederation of about 30 Algonquian-speaking tribes in coastal Virginia. In 1612, the English began intentional settlement of Bermuda with the arrival of the ship Plough. St. George's was designated as Bermuda's first capital, it is the oldest continually inhabited English town in the New World. In 1615, the colony was passed to a new company, the Somers Isles Company, named after the admiral who saved his passengers from Sea Venture. Many Virginian place names refer to the archipelago, such as Bermuda City, Bermuda Hundred; the first English coins to circulate in North America were struck in Bermuda. The archipelago's limited land area and resources led to the creation of what may be the earliest conservation laws of the New World. In 1616 and 1620 acts were passed banning the hunting of young tortoises. In 1
Slash-and-burn agriculture called fire-fallow cultivation, is a farming method that involves the cutting and burning of plants in a forest or woodland to create a field called a swidden. The method begins by cutting down the trees and woody plants in an area; the downed vegetation, or "slash", is left to dry right before the rainiest part of the year. The biomass is burned, resulting in a nutrient-rich layer of ash which makes the soil fertile, as well as temporarily eliminating weed and pest species. After about three to five years, the plot's productivity decreases due to depletion of nutrients along with weed and pest invasion, causing the farmers to abandon the field and move over to a new area; the time it takes for a swidden to recover depends on the location and can be as little as five years to more than twenty years, after which the plot can be slashed and burned again, repeating the cycle. In India, the practice is known as jhoom. Slash-and-burn can be part of shifting cultivation, an agricultural system in which farmers move from one cultivable area to another.
It may be part of transhumance, the moving of livestock between seasons. A rough estimate is. In 2004, it was estimated that in Brazil alone, 500,000 small farmers each cleared an average of one hectare of forest per year; the technique is not sustainable for large human populations. Methods such as Inga alley cropping and slash-and-char have been proposed as alternatives which would cause less environmental degradation. A similar term is assarting, the clearing of forests for the purpose of agriculture. Assarting does not include burning. Slash-and-burn cultivation has been practiced throughout much of the world, in grasslands as well as woodlands. During the Neolithic Revolution, which included agricultural advancements, groups of hunter-gatherers domesticated various plants and animals, permitting them to settle down and practice agriculture, which provides more nutrition per hectare than hunting and gathering; this happened in the river valleys of Mesopotamia. Due to this decrease in food from hunting, as human populations increased, agriculture became more important.
Some groups could plant their crops in open fields along river valleys, but others had forests blocking their farming land. In this context, humans used slash-and-burn agriculture to clear more land to make it suitable for plants and animals. Thus, since Neolithic times, slash-and-burn techniques have been used for converting forests into crop fields and pasture. Fire was used before the Neolithic as well, by hunter-gatherers up to present times. Clearings created by the fire were made for many reasons, such as to draw game animals and to promote certain kinds of edible plants such as berries. Slash-and-burn fields are used and owned by a family until the soil is exhausted. At this point the ownership rights are abandoned, the family clears a new field, trees and shrubs are permitted to grow on the former field. After a few decades, another family or clan may use the land and claim usufructuary rights. In such a system there is no market in farmland, so land is not bought or sold on the open market and land rights are traditional.
In slash-and-burn agriculture, forests are cut months before a dry season. The "slash" is permitted to dry and burned in the following dry season; the resulting ash fertilizes the soil and the burned field is planted at the beginning of the next rainy season with crops such as upland rice, cassava, or other staples. Most of this work is done by hand, using such basic tools such as machetes, axes and makeshift shovels; the old American civilizations, like the Inca and Aztecs used this old agricultural technique. Large families or clans wandering in the lush woodlands long continued to be the most common form of society through human prehistory. Axes to fell trees and sickles for harvesting grain were the only tools people might bring with them. All other tools were made from materials they found at the site, such as fire stakes of birch, long rods, harrows made of spruce tops; the extended family conquered the lush virgin forest and cultivated their selected swidden plots, sowed one or more crops, proceeded on to forests, noted in their wanderings.
In the temperate zone, the forest regenerated in the course of a lifetime. So swidden was repeated several times in the same area over the years, but in the tropics the forest floor depleted. It was not only in the moors, as in Northern Europe, but in the steppe, prairie and barren desert in tropical areas where shifting cultivation is the oldest type of farming. Cultivation is similar to slash-and-burn.. Southern European Mediterranean climates have favored evergreen and deciduous forests. With slash-and-burn agriculture, this type of forest was less able to regenerate than those north of the Alps. Although in northern Europe one crop was harvested before grass was allowed to grow, in southern Europe it was more common to exhaust the soil by farming it for several years. Classical authors mentioned large forests, with Homer writing about "wooded Samothrace," Zakynthos and other woodlands; these authors indicated. Although parts of Europe aside from the north remained wooded, by the Roman Iron and early Viking Ages, forests were drastically reduced and settlements moved.
The reasons for this pattern of mobility, the transition to stable
The Ethiopian Highlands is a rugged mass of mountains in Ethiopia, situated in the Horn region in northeast Africa. It forms the largest continuous area of its elevation in the continent, with little of its surface falling below 1,500 m, while the summits reach heights of up to 4,550 m, it is sometimes called the Roof of Africa due to large area. Most of the Ethiopian Highlands are part of central and northern Ethiopia, its northernmost portion reaches into Eritrea. In the southern parts of the Ethiopian Highlands once was located the Kingdom of Kaffa, a medieval early modern state, whence the coffee plant was exported to the Arabian Peninsula; the land of the former kingdom is mountainous with stretches of forest. The land is fertile, capable of three harvests a year; the term "coffee" is traced to Kaffa. The Highlands are divided into northwestern and southeastern portions by the Main Ethiopian Rift, which contains a number of salt lakes; the northwestern portion, which covers the Tigray and Amhara Regions, includes the Semien Mountains, part of, designated the Simien Mountains National Park.
Its summit, Ras Dashen, is the highest peak in Ethiopia. Lake Tana, the source of the Blue Nile lies in the northwestern portion of the Ethiopian Highlands; the southeastern portion's highest peaks are located in the Bale Zone of Ethiopia's Oromia Region. The Bale Mountains designated a national park, are nearly as high as those of Semien; the range includes peaks of over 4,000 m. Among these are Mount Tullu Demtu, the second-highest peak in Ethiopia, Mount Batu. Most of the country's major cities are located at elevations of around 2,000–2,500 m above sea level, including historic capitals such as Gondar and Axum; the Ethiopian Highlands began to rise 75 million years ago, as magma from the Earth's mantle uplifted a broad dome of the ancient rocks of the Arabian-Nubian Shield. The opening of the Great Rift Valley split the dome of the Ethiopian Highlands into three parts. Around 30 million years ago, a flood basalt plateau began to form, piling layers upon layers of voluminous fissure-fed basaltic lava flows.
Most of the flows were tholeiitic, save for a thin layer of alkali basalts and minor amounts of felsic volcanic rocks, such as rhyolite. In the waning stages of the flood basalt episode, large explosive caldera-forming eruptions occurred; the Ethiopian Highlands were bisected by the Great Rift Valley as the African continental crust pulled apart. This rifting gave rise to large alkaline basalt shield volcanoes beginning about 30–31 million years ago; the northern Ethiopian Highlands contain four discernible planation surfaces the oldest one being formed not than in the Ordovician epoch. The youngest surface formed in the Cenozoic being covered by the Ethiopia-Yemen Continental Flood Basalts. Contrary to what has been suggested for much Africa planation surfaces in northern Ethiopia do not appear to be pediplains nor etchplains; the predominant climate of the Ethiopian Highlands is tropical monsoon, which in general is cooler than in other regions at similar proximity to the equator due to elevation.
Because the highlands elevate Ethiopia, located close to the equator, this has resulted in giving this country an unexpectedly temperate climate. Further, these mountains catch the precipitation of the monsoon winds of the Indian Ocean, resulting in a rainy season that lasts from June until mid-September; these heavy rains cause the Nile to flood in the summer, a phenomenon that puzzled the ancient Greeks, as the summer is the driest season in the Mediterranean climate that they knew. The Ethiopian Highlands share a similar fauna of other mountainous regions of Africa; the habitats are somewhat different on either side of the Great Rift Valley that splits the highlands. At lower elevations, the highlands are surrounded by tropical savannas and grasslands, including the Sahelian acacia savanna to the northwest, the East Sudanian Savanna to the west, the Somali Acacia-Commiphora bushlands and thickets to the northeast, east and through the Rift Valley; the highlands themselves are divided into three distinct ecoregions, distinguished by elevation.
The Ethiopian montane forests lie between 1,100 and 1,800 meters' elevation, above the lowland grasslands and savannas and extends to areas of similar habitat in Eritrea and Djibouti. This woodland belt has several natural plant communities, but has been grazed and converted to agricultural use now. Kolla, is an open woodland found at lower elevations, dominated by species of Terminalia, Commiphora and Acacia. Weyna dega is a woodland found in moister and higher locations, dominated by the conifers Afrocarpus gracilior and Juniperus procera; the lower portion of the Harenna Forest is a distinct woodland community, with an open canopy of Warburgia ugandensis, Croton macrostachyus, Syzygium guineense, Afrocarpus gracilior, with wild coffee as the dominant understory shrub. The southwesterly winds bring rainfall from May to October with moisture from the Red Sea coming in from the east year round. Fauna at these elevations includes the endemic Harwood's francolin, Prince Ruspoli's turaco and yellow-throated seedeater, along with the Djibouti fra
The Galápagos Islands, part of the Republic of Ecuador, are an archipelago of volcanic islands distributed on either side of the equator in the Pacific Ocean surrounding the centre of the Western Hemisphere, 906 km west of continental Ecuador. The islands are known for their large number of endemic species and were studied by Charles Darwin during the second voyage of HMS Beagle, his observations and collections contributed to the inception of Darwin's theory of evolution by means of natural selection. The Galápagos Islands and their surrounding waters form the Galápagos Province of Ecuador, the Galápagos National Park, the Galápagos Marine Reserve; the principal language on the islands is Spanish. The islands have a population of over 25,000; the first recorded visit to the islands happened by chance in 1535, when Fray Tomás de Berlanga, the Bishop of Panamá, was surprised with this undiscovered land during a voyage to Peru to arbitrate in a dispute between Francisco Pizarro and Diego de Almagro.
De Berlanga returned to the Spanish Empire and described the conditions of the islands and the animals that inhabited them. The group of islands was shown and named in Abraham Ortelius's atlas published in 1570; the first crude map of the islands was made in 1684 by the buccaneer Ambrose Cowley, who named the individual islands after some of his fellow pirates or after British royalty and noblemen. These names were used in the authoritative navigation charts of the islands prepared during the Beagle survey under captain Robert FitzRoy, in Darwin's popular book The Voyage of the Beagle; the new Republic of Ecuador took the islands from Spanish ownership in 1832, subsequently gave them official Spanish names. The older names remained in use in English-language publications, including Herman Melville's The Encantadas of 1854. Volcanism has been continuous on the Galápagos Islands for at least 20 myr, even longer; the mantle plume beneath the east-ward moving Nazca Plate has given rise to a 3-kilometre-thick platform under the island chain and seamounts.
Besides the Galápagos Archipelago, other key tectonic features in the region include the Northern Galápagos Volcanic Province between the archipelago and the Galápagos Spreading Center 200 km to the north at the boundary of the Nazca Plate and the Cocos Plate. This spreading center truncates into the East Pacific Rise on the west and is bounded by the Cocos Ridge and Carnegie Ridge in the east. Furthermore, the Galápagos Hotspot is at the northern boundary of the Pacific Large Low Shear Velocity Province while the Easter Hotspot is on the southern boundary; the Galápagos Archipelago is characterized by numerous contemporaneous volcanoes, some with plume magma sources, others from the asthenosphere due to the young and thin oceanic crust. The GSC caused structural weaknesses in this thin lithosphere leading to eruptions forming the Galápagos Platform. Fernandina and Isabela in particular are aligned along these weaknesses. Lacking a well-defined rift zone, the islands have a high rate of inflation prior to eruption.
Sierra Negra on Isabela Island experienced a 240 cm uplift between 1992 and 1998, most recent eruption in 2005, while Fernandina on Fernandina Island indicated an uplift of 90 cm, most recent eruption in 2009. Alcedo on Isabela Island had an uplift of greater than 90 cm, most recent eruption in 1993. Additional characteristics of the Galápagos Archipelago are closer volcano spacing, smaller volcano sizes, larger calderas. For instance, Isabela Island includes 6 major volcanoes, Wolf, Alcedo, Sierra Negraa and Cerro Azul, with most recent eruptions ranging from 1813 to 2008; the neighboring islands of Santiago and Fernandina last erupted in 2009, respectively. Overall, the 9 active volcanoes in the archipelago have erupted 24 times between 1961 and 2011; the shape of these volcanoes is that of an "overturned soup bowl" as opposed to the "overturned saucer plate" of the Hawaiian Islands. The Galápagos's shape is due to the pattern of radial and circumferential fissure, radial on the flanks, but circumferential near the caldera summits.
It is the circumferential fissures. The volcanoes at the west end of the archipelago are in general, younger, have well developed calderas, are composed of tholeiitic basalt, while those on the east are shorter, lack calderas, have a more diverse composition; the ages of the islands, from west to east are 0.05 Ma for Fernandina, 0.65 Ma for Isabela, 1.10 Ma for Santiago, 1.7 Ma for Santa Cruz, 2.90 Ma for Santa Fe, 3.2 Ma for San Cristobal. The calderas on Sierra Negra and Alcedo have active fault systems; the Sierra Negra fault is associated with a sill 2 km below the caldera. The caldera on Fernandina experienced the largest basaltic volcano collapse in history, with the 1968 phreatomagmatic eruption. Fernandina has been the most active volcano since 1790, with recent eruptions in 1991, 1995, 2005, 2009, the entire surface has been covered in numerous flows since 4.3 Ka. The western volcanoes have numerous tuff cones; the islands are located in the eastern Pacific Ocean, 973 km off the west coast of South America.
The closest land mass is that of mainland Ecuador, the country to which they belong, 926 km to the east. The islands are found at the coordinates 1°40'N–1°36'S, 89°16'–92°01'W. Straddling the equator, islands in the chain are located in both the northern and southern hemispheres, with Volcán Wolf and Volcán Ecuador on Isla Isabela being directly on the equator. Española Island, the southernmost islet of the archipelago, Darwin Island, the northernmost
The glacier bear, sometimes referred to as the blue bear, is a subspecies of American black bear with silver-blue or gray hair endemic to Southeast Alaska. Little scientific knowledge exists of the cause of their unique coloration. Most of the other black bears in southeast Alaska are listed under the subspecies Ursus americanus pugnax; the USDA Forest Service lists U. a. emmonsii as one of several subspecies of black bears, although no evidence supports the subspecies designation other than hair coloration. The chief feature distinguishing the glacier bear from other black bears is its pelage, which ranges from silvery blue to gray; the subspecies was reported by Dall in 1895. This variation can be seen on individual bears that are lighter on their backs and shoulders, with their legs and belly being much darker or black; the glacier bear's habitat ranges has been reported to be the Alaskan coastal areas between Cross Sound and Cape St. Elias and from Prince William Sound to Glacier Bay in southeast Alaska, with a few sightings as far east as Juneau and the Taku River.
This region includes Glacier Bay National Park and portions of Tongass National Forest, a temperate rainforest preserve. Few studies document the subspecies' range in association with other black bears. See for instance,Glacier bears share most of the characteristics of black bears such as their habitat preferences, food sources and reproductive cycles, they prefer forest with thick understory and landscapes with lots of vegetation, but can be found in urban populated areas. The glacier bear habitat is dependent upon food source availability, they move between forest, meadows and mountains in search of food and shelter. Black bears in general are capable climbers and can use trees as a place of protection and refuge. Glacier bears move into their dens in early winter, which can be an overturned tree, a rock ledge, or a cave. Glacier bears, like all other black bears, are omnivores, with their diets varying depending on the food source available during the season and the location, their diet includes young roots in early spring.
During the summer in Alaska, the glacier bear eats the abundant Pacific salmon spawning in the streams. In some areas and deer are a food source for black bears. During the fall, the bears eat the starchy roots of ground cones and the variety of berries found in Alaska such as blueberries, salmonberries and cranberries. Breeding habits are much like any other black bear; the glacier bear female has her first litter by 3–5 years of age. This breeding period takes place in June through July. Gestation lasts cubs are born in January to early February; because of the increasing range of all subspecies of black bears since the last glacier maximum, interbreeding is taking place. So, it is possible to see a black-colored bear give birth to a bear with the glacier bears' pelage and vice versa. Little is known about this rare color variation, so some potential threats could become an issue for the glacier bear; some of these threats are gene swamping. No population projections are made due to the lack of genetic understanding.
With the interbreeding capabilities of other black bears with different pelage, determining the future distinctive color variation and population density may become more complicated. Speculation exists that the glacier bear had its origins in hybrids between black bears and grizzlies. Canadian Geographic: The north's elusive: Glacier bear, by Ann Britton Campbell, 139, #1, january/february 2019, pp 37 – 44, cf; the bear that disappears, by the same author, December 2018, added: Link to a video