Coral reefs face immediate peril from several processes.
1/3 of the world's marine fish species are found on the Reefs.
Most home marine aquaria have wild-caught organisms.
There are studies showing that populations of some species have declined in response to harvesting, indicating that the harvest is not sustainable at those levels.
There are concerns about the effect of the pet trade on some species.
There is a brief video discussing the role of marine ecosystems in supporting human welfare and the decline of ocean ecosystems.
In parts of Asia and Africa, hunting practices are thought to be threatening a number of species with extinction.
Bush meat in Africa used to be hunted to feed families directly, but recent commercialization of the practice has increased harvest rates to the level of unsustainability.
Human population growth has increased the need for food that isn't being produced in agriculture.
The bush meat trade is threatening mammals and other primate species.
Kudzu was introduced in the United States in 1876.
It was planted to conserve soil.
It can grow up to a foot a day in the southeastern United States.
It covers over 7 million acres in the southeastern United States.
If an introduced species is able to survive in its new habitat, that is reflected in the observed range of the species.
Human transportation of people and goods, including the intentional transport of organisms for trade, has dramatically increased the introduction of species into new ecosystems, sometimes at distances that are well beyond the capacity of the species to ever travel itself and outside the range of the species' natural predators.
Most exotic species introductions fail because they don't have enough individuals to adapt to the environment they enter.
Pre-adaptations can make some species more successful in a new environment.
Dramatic population increases in their new habitat can threaten the species that exist there.
Exotic species are also called invaders.
Exotic species can threaten other species.
The spotted knapweed, also known as the Eurasian star thistle, has invaded and rendered useless some of the open prairies of the western states.
It is a great flower for the production of honey and supports many pollinating insects, including monarch butterflies in the north-central states.
Lakes and islands are vulnerable to extinction threats.
The introduction of the Nile perch in Lake Victoria caused the extinction of about 200 species of endemic cichlids.
The introduction of the brown tree snake via aircraft from the Solomon Islands to Guam in 1950 has led to the extinction of three species of birds.
Several other species are in danger.
One of the brown tree snakes was found on an aircraft arriving in Texas.
The airport, military, and commercial aircraft personnel need to be on their toes to prevent the snake from moving from Guam to other islands in the Pacific.
Because of their isolation from mainland ancestors, islands have a disproportionate number of endemic species.
The brown tree snake, Boiga irregularis, has caused numerous extinctions on the island of Guam since it was accidentally introduced in 1950.
The African clawed toad (Xenopus laevis) is a commonly used laboratory and pet species and may have been the cause of the spread of the fungus.
It is possible that biologists are responsible for spreading the disease.
The North American bullFrog, Rana catesbeiana, which has also been widely introduced as a food animal but which easily escapes captivity, can act as a reservoir for the disease.
It is a predator in freshwater lakes.
The Limosa Harlequin Frog, an extinct species from Panama, died from a disease.
The red tumors are indicative of the disease.
The Indiana bat, Myotis sodalis, and the Virginia big-eared bat are threatened with extinction because of the disease.
It's not clear how the fungus was introduced, but it's likely that recreational cavers brought it to Europe.
The little brown bat was found in Vermont.
extinction rate estimates range from 15 percent to 40 percent of species destined for extinction by 2050, with scientists disagreeing about the likely magnitude of the effects.
Climate change will alter regional climates, including rainfall and snowfall patterns, making habitats less hospitable to the endemic species.
The warming trend will force species to move with their adapted climate norms while facing habitat gaps along the way.
New competitive regimes will be imposed on species as they find themselves in contact with other species that are not in their historic range.
polar bears and grizzled bears have an unexpected contact.
The two species had different ranges.
There are documented cases of these two species mating and producing viable offspring, which may or may not be viable crossing back to either parent species.
Changing climates make it harder for species to adapt to seasonal food resources and breeding times.
There are many mismatches to shifts in resource availability.
Climate change is thought to be the reason why grizzly bears have been spotted farther north than in the past.
The polar bear habitat overlaps the grizzly bear habitat.
Historically, the two species of bears, which are capable of producing viable offspring, lived in different habitats and never met.
In 2006 a hunter shot a grolar bear, the first wild hybrid ever found.
Some European bird species ranges have moved northward.
The optimal shift based on warming trends was double the distance, suggesting that the populations are not moving quickly enough.
In plants, butterflies, other insects, freshwater fishes, reptiles, and mammals, range shifts have been observed.
Climate change will move up mountains, eventually crowding species higher in altitude and eliminating the habitat for those that are adapted to the highest altitudes.
Some climates will disappear.
The formation of sea ice is greatly reduced by the rate of warming in the arctic.
The only reliable source of food for polar bears and other species is the ice.
Sea ice coverage has been decreasing since the mid-twentieth century, and the rate of decline observed in recent years is far greater than previously predicted.
Global warming will raise ocean levels due to meltwater from glaciers.
A number of islands will disappear and some species will be affected by the reduction of island size.
A cycle that has provided freshwater to environments for centuries will also be jeopardized by the gradual melting of the poles, glaciers, and higher elevation mountains.