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- The number and variety of living organisms, found within a specific area or region as well as all the number and variety of species beyond the region.
- High biodiversity requires sustainable ecosystems.
There is more biodiversity within tropical ecosystems than temperate or boreal ecosystems. Tropical rainforests have the most diversity.
A few good methods of how you can measure biodiversity are through:
- Canopy fogging
- Quadrat Sampling
- Transect Sampling
- and Netting
This is to legally guard from harm a species that is listed as endangered, threatened, or of special concern.
For example;the red mulberry tree and the Peary caribou are of special concern because red mulberry trees are only found in southwestern Ontario, and the Peary caribou are only found in northern Greenland and Canada.
Preserving and protecting individual species and the ecosystems they inhabit are critical to maintaining biodiversity soon Earth.
This is a place where there is an exceptionally large number of species in a relatively small area.
One example of this is Carolinian Canada and the Leitrim Wetlands, both of which are in Canada.
In Carolinian Canada there is around 2,200 different species of plants,(various species of endangered trees and orchids are also included) as well as 40% of Canada's breeding bird species.
The Leitrim Wetlands with not so many different plants is still such an amazing hotspot with more than 200 species of plants and 40 species of birds.
A community is all the populations of the different species that interact in a specific area or ecosystem.
One example of this is the community around a coral reef, the fish, coral, sponges and algae( among many others) are included in this ecosystem.
- Certain species have a greater impact on communities and ecosystems, this is because they fill a specific niche that no one else can fill, some examples of this are:
- The sea otter on the coast of British Columbia
- The American Chestnut tree in various North American forests.
- Dominant species are so abundant that they have the largest biomass of any community member.
- In terrestrial ecosystems, dominant species are always primary producers because consumer biomass is always less than producer biomass.
- One example of this is the mangrove.Around many tropical swamps the mangrove is the dominant species, this may possibly be due to its resistance of tropical tides and weather.
- The removal of a dominant species can cause trouble for their ecosystem. Due to the ecosystem's dependence on these species the sudden removal will cause imbalance and chaos and could destroy the ecosystem.
- A species that can greatly affect population numbers and the health of an ecosystem.
- These species are not as numerous as the dominant ones but are a major part of population control.
- Keystone species are not limited to animals they can also be plants.
One important example of a keystone species would be the sea otters in British Columbia. They control the population of the sea urchin, but during the 20th century their population was greatly reduced due to being hunted by people for their furs. However as their numbers declined the sea urchins increased which caused the kelps biomass to decrease. Afterwards the whole ecosystem started to collapse because everything depended on the kelp.When the sea otters were re-introduced the ecosystem was re-calibrated and the ecosystem was saved.
- This is the breeding of rare or endangered wildlife in controlled settings to increase the population size.
- The captive breeding program was designed to bring back animals from the brink of extinction.
- One place that takes part in these activities is the Toronto Zoo. They have taken part of this program for black-footed ferrets.
- The black-footed ferrets were on the brink of extinction but they were saved by this program. they trained and raised the ferrets as if they were in the wild.
- But to make sure they can be released to the wild there must be a sustainable population of prairie dogs. This is because the ferrets are usually dependent on the population of the prairie dogs
- This is a species that causes such dramatic changes to landscapes that it creates a new ecosystem.
- One example of this is the beaver of North America.The beaver builds dams and cuts down trees to create an ecosystem to support them. These activities create small clearings in the forest that can provide opportunities for other organisms to expand their niche.
- Another example of this would be the giant mesquite bug. It feeds of the stems of the mesquite bush which force it to absorb more nutrients out of the dirt which don't allow any grass to grow. So now most of the desert in Mexico is mesquite bushes. This beetle changed the desert so it can have more bushes to feed off of.
- The series of changes in an ecosystem that occurs over time following a disturbance.
- The easiest example of this can be found in the beaver. The beaver transforms a forest into a flooded forest and then to a sunny pond, which turns to an abandoned pond which can be a beaver pond. This succession is very important because the beaver pond basket-tail dragonfly has its' niche in beaver ponds.Many organisms benefit from a beaver pond, they have fresh water to drink where in normal forest there might be none.
The destruction of habitats, which usually results from human activities.
There are two different categories of habitat loss, there is natural habitat loss and there is human-caused habitat loss.
- For the natural habitat loss there are:
- Volcanic Eruptions
- And severe storms such as hurricanes or tornadoes
For the Human-caused habitat loss there are:
- Draining Wetlands
- Damming rivers
As scientists learn more about the effects of human actions on ecosystems, they are paying more attention to decreasing human impact on ecosystems and restoring ecosystem that have already been altered.
- The practice of clearing forests for logging or other human uses, and never replanting them.
- In some areas of the world,large sections of forests are cut down for timber or clear for agricultural use.
- Tropical forests cover only about 7% of the Earth's land yet, it is estimated that they contain about half of the species on Earth.
- Deforestation in tropical rainforests has resulted in the loss 20-50% of forests in some countries from 1990-2005.
A species that is accidentally or deliberately introduced into a new location.
Not all species that arrive in new places are able to make themselves at home and start reproducing and spreading. However, alien species can get established if given advantages such as:
- an agreeable climate;
- no or few natural predators,
- parasites or diseases;
- an abundance of food plants or prey that lack protection against the newcomer;
- and an ability to out-compete native species and corner the best resources.
One example of this is the european hare.It was originally introduced for game. In that time it has been reproducing and has adapted very well to Ontario, not overpopulating but surviving establishing its own particular niche.
- This is a species that can take over the habitat of native species.
- In many cases invasive species upset the equilibrium of an ecosystem, causing problems for the native species.
- Many invasive species enter various aquatic ecosystems through the ballast water on the ship, this was probably the way that the Zebra Mussel and the Round goby was introduced to North America.
The Zebra Mussel are A freshwater mussel that originated in Asia. It was introduced into the Great Lakes in 1980 through a ship's ballast water. Ever since then the ecosystem is slowly declining. The zebra mussels are better equipped to survive in the ecosystem so a lot of competition arises.
The Round Gobies were introduced into the Great Lakes in 1990. They were Brought in from Asia by ballast water just as the zebra mussels. At first scientists weren't sure what would happen they know for sure that something will happen. This is because they have only been around the great lakes for 10 years and they are already estimated to have at numbers into the billions, only in the western Lake Erie population.
- The use or extraction of a resource until it is depleted.
- Overexploitation can lead to dangerously low population numbers, if not the complete disappearance of a species.
The passenger pigeon at one point had population of over 5 billion, but partly due to overhunting by European hunters they were extinct by the early 1900's.
This is similar to the passenger pigeon. The atlantic cod was once so numerous that they could support communities all over the coast of Newfoundland, at one point it was the major business enterprise of the province. But now due to overfishing everyone is suffering from the loss of the cod. If the species is not looked into it could disappear off the face of the Earth because everyone is still fishing it and that could ruin the ecosystem because the Atlantic Cod was a dominant species along the coast of Newfoundland.
- The death of all of the individuals of the species.
- This happens when the death rate of a species stays higher than the birth rate for a long period of time.
- The birth rate and the death rate have to be in equilibrium for the population to be stable.
- Extinction isn't only caused by human interference it can be caused by the change of a significant abiotic or biotic factor. If there is a great change in climate there will be some species that can't adapt fast enough to survive the change and that is when they go extinct.
- There are two types of extinction mass extinction and background extinction.
Background Extinction happens when the numbers decline slowly over a long period of time until it reaches a point where there aren't any left. One species that this has happened to is the dodo bird. It couldn't withstand its' natural predators that were introduced later in its lifetime
Mass Extinction happens when there is a rapid change to the climate or state of various ecosystems that cause it to be uninhabitable or unsustainable, this can effect many organisms such as the wally mammoth.It could not change fast enough to accompany the climate change so it became extinct and could no longer support itself.
The current accelerated rate of extinctions.
- Species extinction and the degradation of ecosystems are proceeding rapidly and the pace is accelerating. The world is losing species at a rate that is 100 to 1000 times faster than the natural extinction rate.
- The rapid loss of species and the rapid degradation of ecosystems, this is probably a bigger threat than global warming to the stability and future of humankind on Earth.
- The renewal of degraded or destroyed ecosystems through active human intervention.
- A major goal of restoration ecology is to stimulate natural processes of regeneration to produce a sustainable, if not identical, ecosystem.
- One example of this is the Toronto's Don Valley Brick Works . They turned it into a natural environment and cultural heritage park that includes wetlands, a boardwalk, a wildflower meadow, and restored historic buildings. In this situation they re-created what it must have looked like before.
The regrowth of a forest, either through natural processes or through the planting of trees or seeds in an area where a forest was cut down.
- The regrowth of a forest takes many years, but, with proper planning and management, it can be done successfully.
- This happened before in the early 1900's in eastern Canada, red pine trees were planted in land that was cleared for farming by some European farmers. The red pine trees were grown and offered shade for the native trees' seeds so they ended up growing which led to a whole forest.
The use of a species to control the population growth or spread of an undesirable species.
This has happened on an island where the population of rats exploded and reached astronomical numbers, so they brought in monitor lizards to control them. It didn't work, then there were too many monitor lizards so they brought in cane toads which poisoned and killed them but killed livestock as well, so they brought in cats to just die and kill them it didn't work, again. So now they have cane toads and rats.
There are times when this could work but more often then not their will be many negative side effects .
- The use of living organisms to clean up contaminated areas naturally.
- One example of this is when there is a gas station there for along time and the soil becomes too contaminated then they will plant plants there to absorb all the toxicity out of the ground so that the ground can be used again.
The toxicity can come from the underground gas containers leaking or corroding and causing toxins to release.
- This is the use of organisms to add essential nutrients back to depleted soil.
- When an area is depleted of nitrogen they will plant clovers over top of those areas to revitalize the soil with nitrogen.
- Even farmers use this because they will keep rotating their crops so they don't drain one type of nutrient without replacing it. Farmers also plant peanuts to bring nutrients back into the soil.