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33 Cards in this Set
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Miconia in Hawaii
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Miconia is a plant native to Mexico.
Sold in Hawaii in 1960's. Seeds are easily by the Japanese White Eye Bird. Shallow root system Grows and shades out native trees. Replaces native trees' roots with shallow/weak roots placing Hawaii's hillsides at risk for landslides. Has spread to over 40,000 acres. |
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Caulerpa in the Mediterranean Sea
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A species of sea weed used frequently in Aquariums.
Native to the Indian Ocean. Produces a highly toxic poison that kills fish. Accidentally introduced in the Mediterranean Sea from an aquarium. Invasive Species: CP dominates the area it inhabits. It creates competition for natural seaweeds, and in inedible to native species. Effective because it reproduces through cloning. All it takes is one single cell to spread. |
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Natural vs. Human Assited Spread of Invasive Species
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Natural Spread: Invasive species of plants can spread naturally. Birds often pick up seeds and disperse them to different areas.
Human Assisted Spread occurs as a results of involuntary and voluntary actions on the part of humans. For example, many invasive species attach themselves to boats and unwittingly brought into new enviorments ex. Caulpera. |
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Invasive Species
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A species that is not native to the ecosystem under consideration and cause or are likely to cause to an ecosystem's inhabitants.
NOT, a plant or animal species under domestication or cultivation and human controlled species are not. A species might be considered invasive in one region but not in another. Example of the tragedy of the commons. |
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Impacts of Invasive Species
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Human Health:
Respiratory Infection: West Nile Virus in US Poisonous Plants Natural Resources: Declines in wildlife habitat and timber availability Decreased soil stabilaztion and interupted forest succession. Changes in wildfire frequency and intensity. Excessive use of resources Suppressors Decreased carrying capacity for wildlife and livestock. |
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Stages of Invasion
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The process of invasion is characterized by three phases, initial slow growth, exponential growth, and another period of slow growth (Radosevich et al. 2003). These phases represent introduction, colonization, and naturalization, respectively. Richardson et al. (2000) define the following: “Introduction means that the plant (or its propagule) has been transported by humans across a major geographical barrier. Naturalization starts when abiotic (e.g., environmental factors) and biotic (e.g., predators, disease) barriers to survival are surmounted and when various barriers to regular reproduction are overcome. Invasion further requires that introduced plants produce reproductive offspring in areas distant from sites of introduction (approximate scales: greater than 100 meters [328 feet] over 50 years for taxa spreading by seeds and other propagules; greater than 6 meters [20 feet] per three years for taxa spreading by roots, rhizomes, stolons, or creeping stems).” The definition of “invasive species” has been further refined. An invasive species can be placed in three stages of invasion: widespread but rare, localized but dominant, or widespread and dominant. Thus, invasion biologists are moving towards more explicit terms to accurately define an invasive species.
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Islands and Invasive Species
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Islands are particularly vulnerable to invasive species. When a new predator is introduced, many species have no way to evade due to limited space. Limited space also allows for rapid spread.
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Galapagos Islands: Evolution is Isolation
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The periodically changing currents have allowed many different species to immigrate to the islands. Some, such as sea lions, fur seals, and penguins, could swim with the help of the currents and giant tortoises are known to float and could have been carried by the same currents.
Also, during the rainy season, rafts of vegetation break off and float out to sea. Most of the reptiles, the only terrestrial mammals (the rice rats), and insects must have arrived by this route. The light spores of many lower plants could have arrived in the islands by wind along with some vascular plants with lighter seeds. Spiders, small insects, and tiny land snails are frequently transported by wind as well. Land birds and bats, weak fliers, would have to have been blown to the islands, although the seabirds would easily have flown there. The birds would often aid plants by ingesting seeds before takeoff and then expelling them at their destination. Other seeds, with tiny hooks, could have attached to feathers and feet and been given a free ride. Still other seeds, caked in mud and clinging to a bird's feet or feathers would have been transported there as well. |
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Galapogas Islands: Invasive Species
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Feral Goat: The Feral Goat was once in captivity, but escaped. The Goats dominated plant and animal life and multiplied at an alarming rate. Rangers began hunting the Feral Goat and eradicated the problem from most of the islands.
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Adaptive Radiation
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Isolated ecosystems, such as archipelagos, mountain areas, and newly formed lakes can be colonized by a species which, upon establishing itself, undergoes rapid divergent evolution.
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Endemism
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Endemism is the ecological state of being unique to a place. Endemic species are not naturally found elsewhere. The place must be a discrete geographical unit, such as an island, habitat type, or other defined area or zoneEndemic types or species are especially likely to develop on islands because of their geographical isolation. This includes remote island groups, such as Hawaii, the Galápagos Islands and Socotra. Endemism can also occur in biologically isolated areas such as the highlands of Ethiopia, or large bodies of water like Lake Baikal.
Endemics can easily become endangered or extinct because of their restricted habitat and vulnerability to the actions of man, including the introduction of new organisms. There were millions of both Bermuda Petrels and "Bermuda cedars" (actually junipers) in Bermuda when it was settled at the start of the 17th century. By the end of the century, the petrels were thought to be extinct. Cedars, decimated by centuries of shipbuilding, were driven nearly to extinction in the 20th Century by the introduction of a parasite. Both petrels and cedars are very rare today, as are other species endemic or native to Bermuda. |
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Case Study: Foxes and Seabirds on Aleutian Islands
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In Alaska, foxes prey on seabirds. By preying on seabird, foxes reduced nutrient transport from ocean to land, affecting soil fertility and transforming grasslands to dwarf shrub/forb dominated ecosystems.
The foxes were introduced following the decline of the fur trade in the 19th and 20th century. |
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Case Study: Island Fox, Golden Eagles, and Feral Pigs
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Island foxes are vulnerable to eagles who prey on them and are protected by conservation laws.
Foxes have always been controlled because they attack the endangered loggerhead snake. Golden Eagles came to the Channel Islands after the introduction of feral pigs by rangers. Bald Eagles protect the foxes but have disapeared because of DDT dumping. Foxes have also been threatened by the human presence. Unvaccinated dogs brought distember to the island. |
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Brown Tree Snakes on Guam
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a. Brown Tree Snakes first arrived on the Pacific island of Guam shortly after
WWII.
b. Wasn't hard to establish: no competition, no predators c. EFFECT: They have eliminated the natural bird population: now, only two species remain i. The birds on Guam were not biologically evolved to face snakes because snakes eat bird eggs ii. They also cause electrical outage iii. Have a slightly venomous bite iv. Impact local psyche v. Introduced birds have evolved with snakes, so they will be more apt to out-compete the native birds, contributing to their extinction vi. They have recently been found in Hawaii, where they pose a distinct threat to the native bird population there |
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Propagule Pressure
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the measure of the frequency and
persistence of an
introduction. It is the most important factor to invasion success:
species must be arriving often and in high numbers in order to
establish. A high propagule pressure increases the likelihood of a successful establishment.
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Ecologic Release
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: “unhindered proliferation," the idea that a species will expand its habit and resource utilization into an area
in which there
is less species diversity (less competition, more niches to fill).
A species can proliferate more readily in this context.
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Planktonic Larval Stages
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Planktotrophic species, on the other hand, generally have fairly long pelagic larval durations and feed while in the water column. Consequentially, they have the potential to disperse long distances. This ability to disperse is one of the key adaptations of benthic marine invertebrates.[3] During their time in the water column, planktotrophic larvae feed on phytoplankton and small zooplankton, including other larvae. Planktotrophic development is the most common type of larval development, especially among benthic invertebrates.
The relatively long time most planktotrophic larvae spend in the water column and their apparently low probability of successful recruitment led some early researchers to develop a “lottery hypothesis” that states animals release huge numbers of larvae to increase the chances that at least one will survive, and that larvae cannot influence their probability of success.[4][5][6] This hypothesis, though, views larval survival and successful recruitment as chance events, and numerous studies on larval behavior and ecology have shown this to be false.[7] Though it has been generally disproved, the larval lottery hypothesis does represent an important understanding of the difficulties faced by larvae during their time in the water column, particularly because it recognizes the low probability of larval survival. All three types of marine larvae face two major problems: avoiding predation and finding an appropriate site to settle. |
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Green Crabs
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Introduced from Europe by mistake. Most likely hitch hiked on a European vessel (Ballast Water)
Preys on crusteans and soft shelled animals. Has damaged New England fishing. Can be controlled by removal of the crab by fishermen, control of ballast dumping in coastal waters, etc. |
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Out of Eden: What is the greatest myth about nature?
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We tend to think about nature and people as two separate, incompatible worlds. Nature is defined as the wilderness where we aren't; if we touch it or interact with it, it's not natural anymore. Some years ago the writer Bill McKibben took this logic to its extreme: now that human-induced global warming has touched even the most remote parts of the planet, nature, he argued, has ended.
If alien species demonstrate anything, it's the opposite: nature is alive and well, and can thrive even — perhaps especially — in the places where we live. Ecological invasion is sometimes referred to as "biological pollution" or a "green cancer," but those are bad analogies. Traditional pollution kills environments, just as cancer kills people. Ecological invasion doesn't kill ecosystems, it just changes them into other ecosystems that may be less valuable or interesting to people. To put it differently, all biological invasions are natural, whether they occurred with our aid or without it. But not all invasions are desirable. As I traveled around and spent time with various ecologists, I made a point of asking again and again, "So what?" Why not just let everything loose, spread the same plants and animals around the world, homogenize Earth's habitats, and be done with it? What's the harm in that? I heard many answers. Alien species can spread diseases, like the West Nile virus, and can threaten rare or endangered native species, as Hawaii has discovered. But the one common objection was a more personal one: When you start seeing kudzu and dandelions and squirrels everywhere you go on Earth, the world becomes a less interesting place. As one scientist said to me, "We are increasingly dealing with a number of species that are associated with humans throughout the world. If that's what you want to live with — a small suite of a dozen, maybe two dozen species — then you can live with that, I suppose. You can argue that biodiversity has a utilitarian value. But it's an aesthetic issue for me." That surprised me. I'd expected a different sort of answer: That alien species are bad because they're bad for nature. It's true that some invasions do spell trouble for some native species. But really, invasions are bad — or can be bad, in some cases — because they're bad for us, because they change the nature around us and that we're accustomed to. That may sound like a horribly solipsistic way to think about the issue, but there's no avoiding it. The fact is, we could spread all the alien species around the world, and nature wouldn't care. Only we care — which is reason enough for us to care. |
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Out of Eden: What is the strangest invasive species observed?
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A carnivorous inchworm, Eupethicia orichloris — one of about two dozen carnivorous caterpillars that are found only in Hawaii. I saw it in a laboratory, under a microscope; it stood up on one end and looked sort of like a miniature green escalator. Its tail end had these bristly hairs, and if a fly or bug touched them, the front end of the inchworm — which was equipped with clawlike legs — snapped around and grabbed the fly and started munching. The creature ate several flies during the fifteen minutes or so that I watched; it was gripping entertainment, better than the Crocodile Hunter! Hawaii, because it's been evolutionary isolated for so long, is filled with unusual species like carnivorous inchworms that are found nowhere but there.
Actually, reading back through my book, I see that there are few of the usual "charismatic megafauna" in it — no big cuddly animals, not even all that many colorful birds. Mostly I spent time with the small stuff: the inchworms, the cave-dwelling crickets, the sea slugs, the microscopic marine invertebrates, the microbes that live only in NASA's Spacecraft Assembly Facility in Pasadena. It's like a Lost World down there, rich and barely explored, in part because scientists have a hard time getting the necessary funding to explore it; there's more interest in Florida jaguars than, say, the subvisible copepods in Tampa Bay. For exactly that reason, I felt that it was important to enter that world myself and reveal it to the reader. Biological diversity is all about the details, the texture of the fabric of life; it's a texture so fine that most of us can never access it, we may live our whole lives without grasping its extent, or even knowing it's there. Likewise, when biologists talk about how the spread of alien species eats away at biological diversity, often that transformation plays out on these impalpably fine scales. Again, a person might never notice. Fifty percent of the earthworms in American soil are introduced — can you detect a difference? But I like to think there's value in the texture alone, even if there is no large-scale, practical value. In Out of Eden, I wanted to bring that texture to life, if only so that somebody else besides me and a few scientists might glimpse those intimate details. |
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Out of Eden: What is the godzilla of invasive species?
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The brown tree snake, originally from Australia, poses a real threat. Since it first arrived on Guam some fifty years ago, it has managed to eat virtually every bird on the island, and has driven two bird species utterly extinct from Earth. Lately it has begun appearing in Hawaii, which is home to 40 percent of the nation's endangered birds. If it becomes established, it could deal a serious blow to the native birds — which have already been hit hard by introduced avian malaria. Unfortunately, the snake is so good at staying hidden that decades could pass before scientists know for sure that it's living in Hawaii — by which point it will be too late to stop it. The Florida Everglades may have a similar problem now with Asian pythons and boa constrictors; so many have been imported and set free in South Florida that they now live and reproduce outdoors there. A few years ago someone caught a 22-foot python that had been living under a home in suburban Miami.
That said, some of the worst aliens are quite familiar to us. Pet housecats and feral cats, which are originally native to the Near East and Africa, already do tremendous damage to the nation's bird population, but we don't usually consider them an "alien species" problem. The grazing and trampling of livestock, which are likewise introduced species, are a bigger threat to native plants globally than the more exotic alien species one might conjure up. By the same measure, much of what counts as alien-species damage — by introduced insects and pathogens, for instance — is done to our lawns, gardens, and crops, which are themselves made up almost entirely of alien species. We've developed such close, dependent relationships with so many introduced species that we sometimes forget what we mean by "alien." Personally, lately, my biggest alien-species worry is the virus responsible for the avian flu in Asia. If it manages to mutate into a form that can spread directly between humans, instead of simply between poultry and humans, it could quickly jump across borders, with frightening consequences. |
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Out of Eden: Is Burdick for or against Alien Species?
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Well, I'm for them, insofar as I think we can learn a lot from them. By studying what happens when new species enter an environment, scientists have reconsidered many basic assumptions about how ecosystems allegedly work. It turns out that nature is a lot more resilient than we thought, and the ecological rules at play are much less orderly than expected. These insights in turn present the rest of us with some very challenging questions about what we expect and require from nature and how best to achieve it.
That said, alien species do throw into relief the plight of the world's native species — the rare flower pollinated only by one kind of long-beaked bird, or the albino cricket found only in a lava-carved cave in Hawaii. Those organisms represent a timescale — natural selection played out over thousands of years — that vastly exceeds our own individual time on Earth, and that's a timescale worth preserving, I think, if for no other reason than the aesthetics of it: the novelty and strange beauty of these organisms; the fact that they came into being with no help from us, though they now require our artfulness to survive; and the fact that they help give a unique texture to every region of the world. They're like priceless art, and I'm a fan of the arts. |
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Out of Eden: Important Points
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Nature is entering a new era, the Homogecene, as one scientist calls it. Another says if we're not careful, we'll end up with a "McDonald's ecosystem...the same metropolitan animals across the globe." Another biologist said, "There's a loss of the features that allow you to describe where you live."
Five new plants and 20 new insect species are established in Hawaii each year. Not a single plant and none of the lowland birds in Hawaii are native. Many people view Hawaii as paradise, but is it paradise lost -- because we've altered it so? One biologist in Hawaii says that the next phase of conservation is going to be "learning to accept some losses." He says we can spend the same amount of money to save one species or hundreds; which will we choose? The concept of an ecosystem has outlived its usefulness, according to one biologist. There is constant change in nature, not equilibrium. Can we continue to argue against the alteration of the environment? Biologists do have some hope. One explains that we should care about biological invasions for economic reasons -- to keep out potential (economic) nuisances like the zebra mussel inthe Great Lakes; for scientific reasons, so we can study species and ecosystems before they disappear; and for aesthetic reasons, because beauty does matter to people around the world. It's not an either/or situation, this biologist says; it is worth it for us to make an effort to have more biodiversity, to retain the diversity we have in the world. |
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Out of Eden: Feral Pigs
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Burdick tags along with ecologist David Foote, who is studying the impact of the feral pigs. Foote is interested in such questions as whether soil tilled by feral pigs contains fewer native micropods and whether nonnative weeds are more likely to grow in it. Burdick, in translating what he learns from Foote about biogeochemistry, notes rather poetically that "at the lowest trophic levels . . . the animate and inanimate come . . . close to converging: geology melts into soil chemistry; soil chemistry merges with biochemistry; biochemistry begets biology. There is a river of nutrients flowing up and down the scales of perspective."
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Out of Eden: Bio Control Position
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Burdick also brings up biocontrol, the use of other species to attack target invasive organisms. Once an introduced species has built up a large population, control of it by mechanical or chemical means is costly and may harm the environment. Thus it is tempting to try biocontrol instead. Unfortunately, in some cases the creatures used have attacked not only the invader but also native, and often rare, species.
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Yellowstone Ecosystem
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Greater Yellowstone Ecosystem includes: Yellowstone NP, Grand Tetons NP, and Adjacent Forests
Largest intact ecosystem in low US Important terrestrial communities: Coniferous Forests, Mountain Meadows, and Grasslands Important Trees: |
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Fires in the Summer of 1988 in Yellowstone
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Forests and grasslands naturally experience wildfires.
1988: low snowfall in winter+summer drougt=accumulation of dry fuels Most fires started by lightening (few by humans) From July-August over 36% of the park burned. Fire ended by damp weather and early snow in September. The fires did not kill many animals; however, the lack of food the fires created led to wide scale starving. Recovery was suprisingly fast b/c the soil damage was shallow, so roots survived...pine cones opened by the heat of fires spread seeds and germinated quickly...standing dead trees aided recovery by providing habitat. Open ground recieved more sunlight which was good for grasses and herbs. Ash from fires added nutrients to the soil. |
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Yellowstone: Thermophiles
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A thermophile is an organism – a type of extremophile – which thrives at relatively high temperatures, above 45 °C(113°F). Many thermophiles are archaea.
Thermophiles are found in various geothermally heated regions of the Earth such as hot springs like those in Yellowstone National Park (see image) and deep sea hydrothermal vents, as well as decaying plant matter such as peat bogs and compost. As a prerequisite for their survival, thermophiles contain enzymes that can function at high temperature. Some of these enzymes are used in molecular biology (for example heat-stable DNA polymerases for PCR), and in washing agents. Thermophiles are classified into obligate and facultative thermophiles: obligate thermophiles (also called extreme thermophiles) require such high temperatures for growth, while facultative thermophiles (also called moderate thermophiles) can thrive at high temperatures but also at lower temperatures (below 50 °C). Hyperthermophiles are particularly extreme thermophiles for which the optimal temperatures are above 80 °C. |
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Yellowstone: Large Herbivores
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Regulated by availability of of vegetations and predators.
Elk and Bison are important, pronghorn, moose, mule deer, bighorn sheep Beavers: Ecosystem engineers. Cut trees, build damns, and lodges Predators: Wolves,bears, and coyotes elks overgraze and bison spead brucellosis to cattle. |
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Wolf Reintroduction
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Prey on elk and bison
Exterminated in early 20th century Absence of the Wolves: Elk increased, stream side vegetation decreased, beavers decreased leading to more ponds and marshes, more warming of streams led to trout problems. Result of reintroduction: Less elk and coyotes, recovery of many trees along streams, increases in beaver and fox population, carcassess help scavengers, coyotes decline Problem: wolves escape and attack livestock. |
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Other Large Carnivores in Yellowstone
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Brown and Black Bears: Prey on young elk and moose but mixed diet including roots, moths, seeds of whitepark pines.
Coyotes: Resemble wolves but smaller, but very adaptable, top predator in absence of wolves Mountain Lions: Top predator but rarely seen Lynx: Predator that preys on snowshoe hares in boreal forest, lynx and hares reflect 10 year cycles of abundance. |
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Aquatic Invasive Species in Yellowstone
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Native Cutthroat Trout are threatened by other invasive trout species introduced for fishing purposes. These species compete with and hybridize cutthroat trout.
New Zealand Mud Snails invade streams and displace native species which are important food for trout. Humans carry them from stream to stream by mistake usually. Whirling Disease: Attacks fishes nervous system. This leads to a disruptions of their swimming behavior and makes them more vulnerable to predators. |
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Feral Pigs
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Feral Pigs are a dangerous invasive species introduced to Hawaii by hunters.
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