Natural Phenomena - Overpopulation
So... What is 'Overpopulation' ?
Based on wikipedia, Overpopulation occurs when a species' population exceeds the carrying capacity of its ecological niche. It can result from an increase in births (fertility rate), a decline in the mortality rate, an increase in immigration, or an unsustainable biome and depletion of resources. Moreover, it means that if there are too many people in the same habitat, people are limiting available resources to survive.
If a population is 10 people, but there is only enough food for 9 people, then this situation is called overpopulation. If the population is 100 billion, while food is enough for 200 billion, this is not called overpopulation. Resources include: clean water, food, houses, warmth, land to work on. And other smaller factors: work, money, education, fuel, electricity, medicine, sewers, waste management, transportation. This unimportant factor is not needed by primitive animals and humans.
Every year the world population increases by around 80 million. About half of the world's population lives in countries with "sub-replacement fertility and population growth due to immigration.
What causes overpopulation?
Based on Usaha 321 :
1. Introduction of foreign species that do not have natural predators. Often, these species become invasive, as seen in the example above from zebra shells and the introduction of rabbits in Australia.
2. An increase in birth rates will result in population growth, which can lead to overpopulation of a species if the growth exceeds resources in a particular geographical area.
3. The declining mortality rate can result in overpopulation of a species if an increase in the lifespan of a species results in restrictions on resources available in the ecological niche.
4. Reducing available resources can result in overpopulation if the amount of available resources cannot sustain the population in the region. Some examples include desert environments or drought times which make plants and other food sources scarce.
Then, what is the impact?
Based on Usaha 321, In general, excess population causes ecological disturbances when resources run out. This disorder can cause a decline in other populations competing for the same resources. Usually, these impacts result in a turnover between periods of population growth and periods of population decline to reach homeostasis in a particular ecological niche. Some examples of the growth of naturally regulated populations are rodents, rabbits, and various insect populations (for example, army worms and grasshoppers).
In situations of overpopulation caused by the introduction of alien species that do not have natural predators, they can become invasive species. An example is the accidental introduction of zebra mussels to a North American water system. Because zebra shells are native to the Black Sea and the Caspian Sea, they have no natural predators in the foreign ecosystems of North America and parts of Europe. Thus, zebra shells quickly become invasive species, clog water treatment pipes, affect power generation, and impact local freshwater fish populations.
It is estimated that overpopulation of zebra shells has cost around $ 5 billion USD since their introduction. The figure below illustrates zebra mussels infestation in North America because of the overpopulation of zebra mussels in North American waters. Other economic effects of overpopulation include those caused by damage to crops, as seen by the excess rabbit population in Australia. While the excess rabbit population destroys farmers' crops, which leads to poor crop yields, the continent also experiences loss of native plant species, and destruction of topsoil is valuable due to erosion.
Another effect of the overpopulation of one species is the increased growth of the species's natural predator population. This effect is generally considered positive, because the predator population serves to control prey species overpopulation. Such influences also function to encourage evolutionary changes when prey species evolve to avoid increased predation
Then, what's the solution?
Historically, there have been a number of situations where overpopulation of species cannot be managed naturally. In this case, problems with excess population have been overcome using various methods. One of the most common causes of overpopulation is the introduction of alien species to new ecological niches that they have no natural predators.
A well-known example is the introduction of rabbits to Australia in the 19th century, where they had no natural predators. In an effort to control excess rabbit populations in Australia, several different methods are used. Poisons, poaching, rabbit-resistant gates, and introduction of predators (for example, ferrets and cats) are some of the methods used to control rabbit populations. However, after this method failed, scientists released the myxoma virus into the rabbit population. The Myxoma virus is a special rabbit virus that managed to reduce the rabbit population by around 500 million.
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