Misplaced Pages

#514485

80-398: The park covers an area of 726,927 ha (7,269.27 km; 2,806.68 sq mi), making it the largest national park in the country. Established on 11 May 1937, it hosts a representative sample of Magellanic subpolar forest and west Patagonian steppe biodiversity in good state of conservation. In 1981, it was declared a World Heritage Site by UNESCO . The park's name refers to

160-524: A terrestrial ecoregion of southernmost South America, covering parts of southern Chile and Argentina , and are part of the Neotropical realm . It is a temperate broadleaf and mixed forests ecoregion, and contains the world's southernmost forests. The Magellanic subpolar forests ecoregion lies to the west of the Andes Mountains , which run north-south for most of their length but curve eastward near

240-733: A ballast tank of a ship traveling from the temperate zone through tropical waters may experience temperature fluctuations as much as 20 °C. Heat challenges during transport may enhance the stress tolerance of species in their non-native range, by selecting for genotypes that will survive a second applied heat stress, such as increased ocean temperature in the founder population. Invasive species often exploit disturbances to an ecosystem ( wildfires , roads , foot trails ) to colonize an area. Large wildfires can sterilize soils, while adding nutrients . Invasive plants that can regenerate from their roots then have an advantage over natives that rely on seeds for propagation. Invasive species can affect

320-589: A few of the traits, and that noninvasive species had these also. Common invasive species traits include fast growth and rapid reproduction , such as vegetative reproduction in plants; association with humans; and prior successful invasions. Domestic cats are effective predators; they have become feral and invasive in places such as the Florida Keys . An introduced species might become invasive if it can outcompete native species for resources. If these species evolved under great competition or predation , then

400-680: A great decrease in the population size and may constrict genetic variation , the individuals begin to show additive variance as opposed to epistatic variance. This conversion can lead to increased variance in the founding populations, which permits rapid evolution . Selection may then act on the capacity to disperse as well as on physiological tolerance to new stressors in the environment, such as changed temperature and different predators and prey. Rapid adaptive evolution through intraspecific phenotypic plasticity, pre-adaptation and post-introduction evolution lead to offspring that have higher fitness. Critically, plasticity permits changes to better suit

480-470: A habitat in ways advantageous to other species. For example, zebra mussels increase habitat complexity on lake floors, providing crevices in which invertebrates live. This increase in complexity, together with the nutrition provided by the waste products of mussel filter-feeding , increases the density and diversity of benthic invertebrate communities. Introduced species may spread rapidly and unpredictably. When bottlenecks and founder effects cause

560-543: A long taproot , or to live on previously uninhabited soil types. For example, barbed goatgrass was introduced to California on serpentine soils , which have low water-retention, low nutrient levels, a high magnesium / calcium ratio, and possible heavy metal toxicity. Plant populations on these soils tend to show low density, but goatgrass can form dense stands on these soils and crowd out native species. Invasive species might alter their environment by releasing chemical compounds, modifying abiotic factors, or affecting

640-506: A long, bushy tail. Native bird species include the Magellanic woodpecker ( Campephilus magellanicus ), Patagonian sierra-finch ( Phrygilus patagonicus ), Patagonian mockingbird ( Mimus patagonicus ), and Andean condor ( Vultur gryphus ). The rich Magellanic coastal waters and numerous rocky islets host many seabirds, including albatrosses , auks , gulls , terns , and penguins . A 2017 assessment found that 69,938 km², or 46%, of

720-403: A major role in exotic species introduction. High demand for the valuable Chinese mitten crab is one explanation for the possible intentional release of the species in foreign waters. Maritime trade has rapidly affected the way marine organisms are transported within the ocean; new means of species transport include hull fouling and ballast water transport. In fact, Molnar et al. 2008 documented

800-674: A new nomenclature system based on biogeography rather than on taxa . By discarding taxonomy, human health , and economic factors, this model focused only on ecological factors. The model evaluated individual populations rather than entire species. It classified each population based on its success in that environment. This model applied equally to indigenous and to introduced species, and did not automatically categorize successful introductions as harmful. The USDA's National Invasive Species Information Center defines invasive species very narrowly. According to Executive Order 13112, " 'Invasive species' means an alien species whose introduction does or

880-407: A number of years and then experience an explosion in population, a phenomenon known as "the lag effect". Hybrids resulting from invasive species interbreeding with native species can incorporate their genotypes into the gene pool over time through introgression . Similarly, in some instances a small invading population can threaten much larger native populations. For example, Spartina alterniflora

SECTION 10

#1732851934515

960-554: A particular pest species could pollute soil and surface water. Encroachment of humans into previously remote ecosystems has exposed exotic diseases such as HIV to the wider population. Introduced birds (e.g. pigeons ), rodents and insects (e.g. mosquito , flea , louse and tsetse fly pests) can serve as vectors and reservoirs of human afflictions. Throughout recorded history, epidemics of human diseases, such as malaria , yellow fever , typhus , and bubonic plague , spread via these vectors. A recent example of an introduced disease

1040-418: A result of either a numerical or fitness advantage of the introduced species. Genetic pollution occurs either through introduction or through habitat modification, where previously isolated species are brought into contact with the new genotypes. Invading species have been shown to adapt to their new environments in a remarkably short amount of time. The population size of invading species may remain small for

1120-404: A species-rich shrub layer may develop. In exposed, rocky, and poorly drained areas, pockets of deciduous Nothofagus antarctica and the typical moorland species can be found. As one moves further east, where rainfall decreases to 800–850 mm/a (31.5–33.5 in/a), Nothofagus betuloides becomes less dominant and mixes with deciduous Nothofagus pumilio in the transition to

1200-456: Is highly fire-adapted. It spreads rapidly after burning, and increases the frequency and intensity of fires by providing large amounts of dry detritus during the fire season in western North America. Where it is widespread, it has altered the local fire regimen so much that native plants cannot survive the frequent fires, allowing it to become dominant in its introduced range. Ecological facilitation occurs where one species physically modifies

1280-623: Is likely to cause economic or environmental harm or harm to human health." Typically, an introduced species must survive at low population densities before it becomes invasive in a new location. At low population densities, it can be difficult for the introduced species to reproduce and maintain itself in a new location, so a species might reach a location multiple times before it becomes established. Repeated patterns of human movement, such as ships sailing to and from ports or cars driving up and down highways, offer repeated opportunities for establishment (a high propagule pressure ). In ecosystems ,

1360-600: Is normal, and preserves constellations of genes and genotypes. An example of this is the interbreeding of migrating coyotes with the red wolf , in areas of eastern North Carolina where the red wolf was reintroduced, reducing red wolf numbers. In South Africa's Cape Town region, analysis demonstrated that the restoration of priority source water sub-catchments through the removal of thirsty alien plant invasions (such as Australian acacias, pines and eucalyptus, and Australian black wattle) would generate expected annual water gains of 50 billion liters within 5 years compared to

1440-581: Is now considered invasive in over 60 countries, and has invaded large geographies in several countries prompting aggressive federal efforts at attempting to control it. Primary geomorphological effects of invasive plants are bioconstruction and bioprotection. For example, kudzu ( Pueraria montana ), a vine native to Asia, was widely introduced in the southeastern United States in the early 20th century to control soil erosion . The primary geomorphological effects of invasive animals are bioturbation , bioerosion , and bioconstruction. For example, invasions of

1520-479: Is one of the most problematic invasive plant species in eastern North American forests, where it is highly invasive of the understory , reducing the growth rate of tree seedlings and threatening to modify the forest's tree composition. Native species can be threatened with extinction through the process of genetic pollution . Genetic pollution is unintentional hybridization and introgression , which leads to homogenization or replacement of local genotypes as

1600-570: Is poorly defined and often very subjective. Invasive species may be plants, animals, fungi, and microbes; some include native species that have invaded human habitats such as farms and landscapes. Some broaden the term to include indigenous or "native" species that have colonized natural areas. Some sources name Homo sapiens as an invasive species, but broad appreciation of human learning capacity and their behavioral potential and plasticity may argue against any such fixed categorization. The definition of "native" can be controversial. For example,

1680-510: Is the main cause of introductions – other than for polar regions . Diseases may be vectored by invasive insects: the Asian citrus psyllid carries the bacterial disease citrus greening . The arrival of invasive propagules to a new site is a function of the site's invasibility. Many invasive species, once they are dominant in the area, become essential to the ecosystem of that area, and their removal could be harmful. Economics plays

SECTION 20

#1732851934515

1760-587: Is the spread of the West Nile virus , which killed humans, birds, mammals, and reptiles. The introduced Chinese mitten crabs are carriers of Asian lung fluke . Waterborne disease agents, such as cholera bacteria ( Vibrio cholerae ), and causative agents of harmful algal blooms are often transported via ballast water. Globally, invasive species management and control are substantial economic burdens, with expenditures reaching approximately $ 1.4 trillion annually. The economic impact of invasive alien species alone

1840-486: The Age of Discovery , and accelerating again with international trade . Notably invasive plant species include the kudzu vine, giant hogweed , Japanese knotweed , and yellow starthistle . Notably invasive animals include European rabbits , domestic cats , and carp . Invasive species are the subset of established non-native alien or naturalized species that are a threat to native species and biodiversity. The term "invasive"

1920-516: The Great Lakes via ballast water. These outcompete native organisms for oxygen and food, and can be transported in the small puddle left in a supposedly empty ballast tank. Regulations attempt to mitigate such risks, not always successfully. Climate change is causing an increase in ocean temperature . This in turn will cause range shifts in organisms, which could harm the environment as new species interactions occur. For example, organisms in

2000-591: The economic returns from invasive species are far less than the costs they impose. In the Great Lakes region the sea lamprey is an invasive species. In its original habitat, it had co-evolved as a parasite that did not kill its host. However, in the Great Lakes Region, it acts as a predator and can consume up to 40 pounds of fish in its 12–18 month feeding period. Sea lampreys prey on all types of large fish such as lake trout and salmon . The sea lampreys' destructive effects on large fish negatively affect

2080-844: The extinction of species, loss in biodiversity, and loss of ecosystem services , costs from impacts of invasive species would drastically increase. It is often argued that the key to invasive species management is early detection and rapid response. However, early response only helps when the invasive species is not frequently reintroduced into the managed area, and the cost of response is affordable. Weeds reduce yield in agriculture . Many weeds are accidental introductions that accompany imports of commercial seeds and plants. Introduced weeds in pastures compete with native forage plants, threaten young cattle (e.g., leafy spurge, Euphorbia virgata ) or are unpalatable because of thorns and spines (e.g., yellow starthistle ). Forage loss from invasive weeds on pastures amounts to nearly US$ 1 billion in

2160-458: The southern pudú ( Pudu puda ), the world's smallest deer , which stands only 35–45 cm (14–18 inches) high at the shoulder. Other animal species include the cougar ( Puma concolor ) and the endangered southern river otter ( Lontra provocax ). Endemic rodents include the Patagonian mara , the long-clawed mole mouse , and the viscacha , a small rodent that looks almost like a rabbit with

2240-744: The spatial scale of invasion studies. Small-scale studies tended to show a negative relationship between diversity and invasion, while large-scale studies tended to show the reverse, perhaps a side-effect of invasives' ability to capitalize on increased resource availability and weaker species interactions that are more common when larger samples are considered. However, this pattern does not seem to hold true for invasive vertebrates. Island ecosystems may be more prone to invasion because their species face few strong competitors and predators, and because their distance from colonizing species populations makes them more likely to have "open" niches. For example, native bird populations on Guam have been decimated by

2320-445: The 20th century, invasive species have become serious economic, social, and environmental threats worldwide. Invasion of long-established ecosystems by organisms is a natural phenomenon, but human-facilitated introductions have greatly increased the rate, scale, and geographic range of invasion. For millennia, humans have served as both accidental and deliberate dispersal agents, beginning with their earliest migrations , accelerating in

2400-467: The 958 endangered species under the Endangered Species Act are at risk. The unintentional introduction of forest pest species and plant pathogens can change forest ecology and damage the timber industry . Overall, forest ecosystems in the U.S. are widely invaded by exotic pests, plants, and pathogens. The Asian long-horned beetle ( Anoplophora glabripennis ) was first introduced into

2480-684: The Atlantic. Between the two halves is a non-touristic zone without lakes called Zona Centro . The northern half consists of part of Viedma Lake , the Viedma Glacier and a few minor glaciers, and a number of mountains very popular among fans of climbing and trekking, including Mount Fitz Roy and Cerro Torre . The southern part has, as well as a number of smaller ones, the major glaciers which flow into Lake Argentino: Perito Moreno Glacier , Upsala Glacier , and Spegazzini Glacier . Typical excursion boats travel between icebergs to visit Onelli Bay , and

Los Glaciares National Park - Misplaced Pages Continue

2560-518: The California sea otter ( Enhydra lutris ). Invasive species appear to have specific traits or specific combinations of traits that allow them to outcompete native species . In some cases, the competition is about rates of growth and reproduction. In other cases, species interact with each other more directly. One study found that 86% of invasive species could be identified from such traits alone. Another study found that invasive species often had only

2640-493: The Chinese mitten crab ( Eriocheir sinensis ) have resulted in higher bioturbation and bioerosion rates. A native species can become harmful and effectively invasive to its native environment after human alterations to its food web . This has been the case with the purple sea urchin ( Strongylocentrotus purpuratus ), which has decimated kelp forests along the northern California coast due to overharvesting of its natural predator,

2720-761: The South Atlantic to the South Pacific. North of roughly 48° south latitude lies the Valdivian temperate forests ecoregion, which shares many affinities with the Magellanic ecoregion in plant and animal life. To the east lie the drier temperate grasslands and shrublands ecoregions of Patagonia , which are in the rain shadow of the Andean and Fuegian mountains. The Andean and Fuegan mountains intercept moisture-laden westerly winds, creating temperate rain forest conditions, while

2800-517: The U.S. A decline in pollinator services and loss of fruit production has been caused by honey bees infected by the invasive varroa mite . Introduced rats ( Rattus rattus and R. norvegicus ) have become serious pests on farms, destroying stored grains. The introduction of leaf miner flies ( Agromyzidae ), including the American serpentine leaf miner ( Liriomyza trifolii ), to California has caused losses in California's floriculture industry, as

2880-544: The U.S. in 1996, and was expected to infect and damage millions of acres of hardwood trees. As of 2005 thirty million dollars had been spent in attempts to eradicate this pest and protect millions of trees in the affected regions. The woolly adelgid has inflicted damage on old-growth spruce, fir and hemlock forests and damages the Christmas tree industry. Chestnut blight and Dutch elm disease are plant pathogens with serious impacts. Garlic mustard, Alliaria petiolata ,

2960-591: The alteration in ecosystem functionality (due to homogenization of biota communities), invasive species have resulted in negative effects on human well-being, which includes reduced resource availability, unrestrained spread of human diseases, recreational and educational activities, and tourism. Alien species have caused diseases including human immunodeficiency virus (HIV), monkey pox , and severe acute respiratory syndrome (SARS). Invasive species and accompanying control efforts can have long term public health implications. For instance, pesticides applied to treat

3040-607: The ancestors of Equus ferus (modern horses) evolved in North America and radiated to Eurasia before becoming extinct in North America. Upon being introduced to North America in 1493 by Spanish conquistadors , it is debatable whether the feral horses were native or exotic to the continent of their evolutionary ancestors. While invasive species can be studied within many subfields of biology, most research on invasive organisms has been in ecology and biogeography . Much of

3120-478: The availability of resources determines the impact of additional species on the ecosystem. Stable ecosystems have a resource equilibrium, which can be changed fundamentally by the arrival of invasive species. When changes such as a forest fire occur, normal ecological succession favors native grasses and forbs . An introduced species that can spread faster than natives can outcompete native species for food, squeezing them out. Nitrogen and phosphorus are often

3200-467: The behaviour of herbivores , impacting on other species. Some, like Kalanchoe daigremontana , produce allelopathic compounds that inhibit competitors. Others like Stapelia gigantea facilitate the growth of seedlings of other species in arid environments by providing appropriate microclimates and preventing herbivores from eating seedlings. Changes in fire regimens are another form of facilitation. Bromus tectorum , originally from Eurasia,

3280-507: The business-as-usual scenario (which is important as Cape Town experiences significant water scarcity ). This is the equivalent to one-sixth of the city's current supply needs. These annual gains will double within 30 years. The catchment restoration is significantly more cost-effective then other water augmentation solutions (1/10 the unit cost of alternative options). A water fund has been established, and these exotic species are being eradicated. Invasive species can affect human health. With

Los Glaciares National Park - Misplaced Pages Continue

3360-469: The cold oceanic Humboldt Current , which runs up the west coast of South America, and the cold Antarctic Circumpolar Current , which runs from west to east through the Southern Ocean , keep the Magellanic ecoregion cool and wet, and the strong oceanic influence moderates seasonal temperature extremes. Average annual temperatures vary from 6 °C (42.8 °F) in the north to 3 °C (37.4 °F) in

3440-449: The deciduous forest community. The Magellanic deciduous forest is made up mostly of Nothofagus pumilio and Nothofagus antarctica . When one reaches the drier rain shadow east of the mountains, the forests disappear, transitioning to the grassland ecoregions of Patagonia. In open spaces some succulent fruits can be found: Chilean strawberry ( Fragaria chiloensis ), and calafate ( Berberis microphylla ); they used to complement

3520-511: The densities of native forage plants, declining the habitat-use by wild herbivores and threatening the long-term sustenance of dependent carnivores, including the tiger . Invasive species can change the functions of ecosystems. For example, invasive plants can alter the fire regime (cheatgrass, Bromus tectorum ), nutrient cycling (smooth cordgrass Spartina alterniflora ), and hydrology ( Tamarix ) in native ecosystems. Invasive species that are closely related to rare native species have

3600-414: The ecoregion is in protected areas. Invasive species An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions , causing ecological, environmental, and/or economic damage. The term can also be used for native species that become harmful to their native environment after human alterations to its food web . Since

3680-436: The expense to monitor, control, manage, and research invasive weed species is approximately AU$ 116.4 million per year, with costs directed solely to central and local government. While in some cases, invasive species may offer economic benefits, such as the potential for commercial forestry from invasive trees, these benefits are generally overshadowed by the substantial costs associated with biological invasions. In most cases,

3760-563: The field lacks any official designation but is commonly referred to as "invasion ecology" or more generally "invasion biology". This lack of standard terminology has arisen due to the interdisciplinary nature of the field which borrows terms from disciplines such as agriculture , zoology , and pathology , as well as due to studies being performed in isolation. In an attempt to avoid the ambiguous, subjective, and pejorative vocabulary that so often accompanies discussion of invasive species even in scientific papers, Colautti and MacIsaac proposed

3840-629: The fishing industry and have helped cause the collapse of the population of some species. Economic costs from invasive species can be separated into direct costs through production loss in agriculture and forestry, and management costs. Estimated damage and control costs of invasive species in the U.S. amount to more than $ 138 billion annually. Economic losses can occur through loss of recreational and tourism revenues. When economic costs of invasions are calculated as production loss and management costs, they are low because they do not consider environmental damage; if monetary values were assigned to

3920-406: The forests to retreat far to the north, and the region was gradually reforested starting about 10,000 years ago when the climate warmed and the glaciers began retreating. The Magellanic ecoregion has three main plant communities: the Magellanic moorland , the evergreen Magellanic rainforest, and the deciduous Magellanic forest. The Magellanic moorland occurs on the western edge of the region where

4000-592: The giant ice cap in the Andes , the largest outside of Antarctica , Greenland and Iceland , feeding 47 large glaciers , of which 13 flow towards the Pacific Ocean . In other parts of the world, glaciers start at a height of at least 2,500 m (8,200 ft) above mean sea level , but due to the size of the ice cap, these glaciers begin at only 1,500 m (4,900 ft), sliding down to 200 m (660 ft). Los Glaciares borders Torres del Paine National Park to

4080-446: The governments of California and New Zealand have announced more stringent control for vessel hull fouling within their respective jurisdictions. Another vector of non-native aquatic species is ballast water taken up at sea and released in port by transoceanic vessels. Some 10,000 species are transported via ballast water each day. Many of these are harmful. For example, freshwater zebra mussels from Eurasia most likely reached

SECTION 50

#1732851934515

4160-489: The individual to its environment. Pre-adaptations and evolution after the introduction reinforce the success of the introduced species. The enemy release hypothesis states that evolution leads to ecological balance in every ecosystem. No single species can occupy a majority of an ecosystem due to the presences of competitors, predators, and diseases. Introduced species moved to a novel habitat can become invasive, with rapid population growth, when these controls do not exist in

4240-619: The introductions of the amethyst gem clam and the European green crab . The gem clam was introduced into California's Bodega Harbor from the US East Coast a century ago. On its own, it never displaced native clams ( Nutricola spp.). In the mid-1990s, the introduction of the European green crab resulted in an increase of the amethyst gem at the expense of the native clams. In India, multiple invasive plants have invaded 66% of natural areas, reducing

4320-538: The invaded habitats and bioregions adversely, causing ecological, environmental, or economic damage. The European Union defines "Invasive Alien Species" as those that are outside their natural distribution area, and that threaten biological diversity . Biotic invasion is one of the five top drivers for global biodiversity loss , and is increasing because of tourism and globalization . This may be particularly true in inadequately regulated fresh water systems, though quarantines and ballast water rules have improved

4400-646: The invasive brown tree snake . In New Zealand the first invasive species were the dogs and rats brought by Polynesian settlers around 1300. These and other introductions devastated endemic New Zealand species. The colonization of Madagascar brought similar harm to its ecosystems. Logging has caused harm directly by destroying habitat, and has allowed non-native species such as prickly pear and silver wattle to invade. The water hyacinth forms dense mats on water surfaces, limiting light penetration and hence harming aquatic organisms, and causing substantial management costs. The shrub lantana ( Lantana camara )

4480-748: The latter of which has suffered from the invasion of the cattle industry and are endangered . The guanaco, while not endangered, has had a dramatic decline in historic population due to large scale grazing of livestock throughout much of Patagonia. There are over 100 species of birds in the area ( condors , eagles , and others). Between the ice and the Patagonian steppe there is a fertile area of Magellanic subpolar forests composed mainly of lengas and guindos , but also ñires . Within these more hospitable areas also live huemul deer and torrent duck . Los Glaciares National Park faces many issues around tourism, overgrazing , forest fires and more. There are areas of

4560-443: The limiting factors in these situations. Every species occupies an ecological niche in its native ecosystem; some species fill large and varied roles, while others are highly specialized. Invading species may occupy unused niches, or create new ones. For example, edge effects describe what happens when part of an ecosystem is disturbed, as when land is cleared for agriculture . The boundary between remaining undisturbed habitat and

4640-630: The new ecosystem. Non-native species have many vectors , but most are associated with human activity. Natural range extensions are common, but humans often carry specimens faster and over greater distances than natural forces. An early human vector occurred when prehistoric humans introduced the Pacific rat ( Rattus exulans ) to Polynesia. Vectors include plants or seeds imported for horticulture . The pet trade moves animals across borders, where they can escape and become invasive. Organisms stow away on transport vehicles. Incidental human assisted transfer

4720-523: The new environment may host fewer able competitors, allowing the invader to proliferate. Ecosystems used to their fullest capacity by native species can be modeled as zero-sum systems, in which any gain for the invader is a loss for the native. However, such unilateral competitive superiority (and extinction of native species with increased populations of the invader) is not the rule. An invasive species might be able to use resources previously unavailable to native species, such as deep water accessed by

4800-528: The newly cleared land itself forms a distinct habitat, creating new winners and losers and possibly hosting species that would not thrive outside the boundary habitat. In 1958, Charles S. Elton claimed that ecosystems with higher species diversity were less subject to invasive species because fewer niches remained unoccupied. Other ecologists later pointed to highly diverse, but heavily invaded ecosystems, arguing that ecosystems with high species diversity were more susceptible to invasion. This debate hinged on

4880-495: The nourishment of the (now almost nonexistent) native peoples. These forests are peerless in their endurance of cold summers (averaging 9 degrees Celsius or 48.2 degrees Fahrenheit at sea level) and violent subpolar winds . Due to these traits, Magellanic forests' tree species are exported to other parts of the world such as the Faroe Islands and neighboring archipelagos with similar conditions where trees from other biomes in

SECTION 60

#1732851934515

4960-409: The ocean, in more moderate areas less exposed to the oceanic wind and rain, moorland yields to evergreen Magellanic rainforest. The Magellanic rainforest is mostly made up Nothofagus betuloides , together with other evergreen trees, most often Drimys winteri and Pilgerodendron uviferum , and occasionally Embothrium coccineum and Maytenus magellanica . In the better established forest stands,

5040-646: The oceanic influence is strongest. High rainfall of 5,000 mm/a (197 in/a) is typical of the moorland, as are cool temperatures, strong winds, bad drainage conditions, and rocky ground with generally thin soil. Most of the moorland consists of a mosaic of low-growing plants, including dwarf shrubs and wind-sheared trees, cushion plants, grasses, and mosses. These plants can form an underlayer of blanket peat and boggy areas. In more sheltered areas, small stands of evergreen forest can be found, which include Nothofagus betuloides , Drimys winteri , Lepidothamnus fonkii , and Pilgerodendron uviferum . Farther from

5120-420: The otherwise inaccessible Spegazzini and Upsala. Perito Moreno is reachable by land. The park has a cool and moist temperate climate. Mean temperatures range from 0.6 °C (33.1 °F) in winter to 13.4 °C (56.1 °F) in summer although at higher altitudes, the mean annual temperature can be around −3 °C (26.6 °F). The park receives an average annual rainfall of 500 mm (20 in) in

5200-419: The park where overgrazing is quite a problem and contains many alien/ invasive and feral species such as cattle, European hares and certain types of trout. Forest fires have had a strong impact on the site and degraded and destroyed parts of it as well. Los Glaciares is a major attraction for international tourists. Starting points of tours are the city of El Calafate at the shore of Lake Argentino but outside

5280-615: The park, where the park's administration has its headquarters, and El Chaltén village in the northern part of the park, at the foot of the Fitz Roy. Other touristic points in the park include Lago del Desierto and Lago Roca . It was also used as one of the filming locations for "Return of the Ice", the second episode of the speculative science documentary series The Future is Wild . Magellanic subpolar forest The Magellanic subpolar forests ( Spanish : Bosque Subpolar Magallánico ) are

5360-476: The pathways of hundreds of marine invasive species and found that shipping was the dominant mechanism for the transfer of invasive species. Many marine organisms can attach themselves to vessel hulls. Such organisms are easily transported from one body of water to another, and are a significant risk factor for a biological invasion event. Controlling for vessel hull fouling is voluntary and there are no regulations currently in place to manage hull fouling. However,

5440-464: The potential to hybridize with the native species. Harmful effects of hybridization have led to a decline and even extinction of native species. For example, hybridization with introduced cordgrass, Spartina alterniflora , threatens the existence of California cordgrass ( Spartina foliosa ) in San Francisco Bay . Invasive species cause competition for native species and because of this 400 of

5520-412: The situation. Invasive species may drive local native species to extinction via competitive exclusion, niche displacement, or hybridisation with related native species. Therefore, besides their economic ramifications, alien invasions may result in extensive changes in the structure, composition and global distribution of the biota at sites of introduction, leading ultimately to the homogenisation of

5600-558: The south and annual rainfall from 4,000 mm (157 in) in the west to 450 mm (17.7 in) in the east. Snowfalls are very common in the west and can occur even in summer. Fog is very frequent. Very strong winds whip the region compelling trees to grow in twisted and bent shapes known as flag trees . Like the Valdivian ecoregion, the Magellanic subpolar forests are a refuge for the Antarctic flora , and share many plant families with

5680-630: The south in Chilean territory. Los Glaciares, of which 30% is covered by ice, can be divided in two parts, each corresponding with one of the two elongated big lakes partially contained by the park. Lake Argentino , 1,466 km (566 sq mi) and the largest in Argentina, is in the south, while Lake Viedma , 1,100 km (420 sq mi), is in the north. Both lakes feed the Santa Cruz River that flows down to lower part Puerto Santa Cruz on

5760-539: The southern tip of South America, terminating at the archipelago of Tierra del Fuego . The Magellanic ecoregion was covered by glaciers during the last ice age , and the landscape is deeply dissected by fjords , with numerous islands, inlets, and channels, including the Strait of Magellan , which separates Tierra del Fuego from the South American mainland and is the route taken by Portuguese explorer Ferdinand Magellan from

5840-551: The spread of biological invasions, mitigate further impacts, and restore affected ecosystems. For example, the damage caused by 79 invasive species between 1906 and 1991 in the United States has been estimated at US$ 120 billion. Similarly, in China , invasive species have been reported to reduce the country's gross domestic product (GDP) by 1.36% per year. The management of biological invasions can be costly. In Australia , for instance,

5920-492: The temperate forest ecoregions of New Zealand , Tasmania , and Australia , especially the southern beech ( Nothofagus ). Species of Nothofagus , including N. betuloides , N. antarctica , and N. pumilio , are the characteristic trees of the Magellanic ecoregion. The Magellanic ecoregion does not have the same species richness as the milder Valdivian ecoregion, both on account of its colder climate and its recent glaciation. The advancing glaciers caused

6000-510: The west and 900 mm (35 in) in the east which is evenly distributed throughout the year. Snowfall is common during the colder months. The mountains hold most of the humidity from the Pacific Ocean , letting through only the ice coldness (annual average of 7.5 °C (45.5 °F)) and creating the arid Patagonian steppe on the Argentine side of the range. This area is habitat for rheas , guanaco , cougar , and South American gray fox ,

6080-502: The work has been influenced by Charles Elton's 1958 book The Ecology of Invasion by Animals and Plants which creates a generalized picture of biological invasions. Studies remained sparse until the 1990s. This research, largely field observational studies, has disproportionately been concerned with terrestrial plants . The rapid growth of the field has driven a need to standardize the language used to describe invasive species and events. Despite this, little standard terminology exists;

6160-477: The world cannot grow. The following species from Tierra del Fuego , Drimys winteri , Nothofagus antarctica , Nothofagus pumilio , and Nothofagus betuloides , have been successfully introduced to the Faroe Islands. As a general rule, Fueguian trees show better signs of acclimation than those from Continental Northern Europe to conditions in the Faroe Islands. The Magellanic subpolar forests are home to

6240-405: The world's fauna and flora and the loss of biodiversity . It is difficult to unequivocally attribute extinctions to a species invasion, though there is for example strong evidence that the extinction of about 90 amphibian species was caused by the chytrid fungus spread by international trade. Multiple successive introductions of different non-native species can worsen the total effect, as with

6320-416: Was estimated to exceed $ 423 billion annually as of 2019. This cost has exhibited a significant increase, quadrupling every decade since 1970, underscoring the escalating financial implications of these biological invasions. Invasive species contribute to ecological degradation , altering ecosystem functionality and reducing the services ecosystems provide. This necessitates additional expenditures to control

6400-462: Was introduced in the San Francisco Bay and hybridized with native Spartina foliosa . The higher pollen count and male fitness of the invading species resulted in introgression that threatened the native populations due to lower pollen counts and lower viability of the native species. Reduction in fitness is not always apparent from morphological observations alone. Some degree of gene flow

#514485