Ecological crisis is a special type of ecological situation when the habitat of one of a species or population changes in such a way that casts doubt on its further existence. The main causes of the crisis:
- Abiotic: environmental quality degrades compared to the needs of the species after changing abiotic environmental factors (e.g., increasing temperature or decreasing rainfall).
- Biotic: the environment becomes difficult for a species (or population) to survive due to increased pressure from predators or due to overpopulation .
- Anthropogenic: the environment is deteriorating as a result of human activities (misuse and distribution of limited natural resources , emissions of harmful greenhouse gases into the atmosphere by enterprises, etc.).
A crisis may be:
- global;
- local.
To deal with the global environmental crisis is much more difficult than with the local one. A solution to this problem can only be achieved by minimizing the pollution produced by humanity to a level that ecosystems will be able to cope on their own. Currently, the global environmental crisis includes four main components: acid rain , the greenhouse effect , pollution of the planet with super-ecotoxicants, and the so-called ozone holes .
The evolutionary theory of intermittent equilibrium suggests that rare environmental crises can be the engine of rapid evolution.
Content
Abiotic factors
Climate change is beginning to strongly affect ecosystems. Due to global warming , there is a decrease in snowfall and sea level rises. Ecosystems will have to change to coexist with rising temperatures. As a result, many species can leave their habitats.
Polar bears are in danger. They need ice to hunt their main food - fur seals. At the same time, ice caps are melting, making the hunting season shorter every year. As a result, they do not gain enough fat for wintering; and therefore can not multiply in the amount necessary to preserve the population.
Freshwater and bog ecosystems are also strongly affected by temperature increases. Climate change can be fatal for some species of fish (salmon, trout, etc.).
Many species will be able to adapt by moving their habitats closer to the poles, while others are less fortunate. For example, polar bears or salmon will have nowhere to move.
Species extinction
A huge number of species disappears. Every year from 17 to 100 thousand species disappear. The rate at which species become endangered has grown tremendously in recent years.
The extinction of species from the ecosystem will sooner or later affect everyone. In the United States and Canada, an unusual decline in shark populations along the east coast has been recorded. At the same time, an increase in the population of stingrays was recorded, which, in turn, reduced the number of crustaceans in the same region by an order of magnitude. A reduction in the number of crustaceans has led to a deterioration in water quality and a reduction in underwater fields. The variety of species is declining at tremendous speed. Seven million square kilometers of rainforest have disappeared over the past 50 years. Two million of them were subsequently used for agriculture, the remaining five are not suitable for this. To return the forest to them requires about five billion tons of carbon from the atmosphere every year for 10-20 years. Afforestation , however, will greatly benefit species diversity.
Overpopulation
In the wild, the problem of overpopulation is solved with the help of predators . Predators perfectly notice the traces of the disease in their victims and eat mainly old and sick. A side effect is the survival of the strongest and limitation of population growth.
In the absence of predators, species are limited by the resources that they can find in the habitat, but this does not always constrain overpopulation. In fact, an abundance of resources can cause a fertility boom , which will result in more consumers in the region than it can feed. In this case, hunger and fierce competition for impoverished resources will lead the population to collapse, and very quickly. Lemmings and some other rodents are known for such periods of rapid growth and subsequent fall.
Ideally, along with population growth, the population of predators that feed on it grows. Animals that are genetically weak or have birth defects also die soon, being unable to compete for survival with healthy ones.
In reality, animals that appeared in the region from outside have an advantage over local ones, for example, they can be "inedible" for local predators. In the absence of control, such animals can instantly grow in number and virtually destroy the ecosystem.
Examples of overpopulation caused by species introduced into the ecosystem.
- In Argentina ( Patagonia ), alien species such as trout and sheep imported from Europe turned out to be worse than the plague, displacing local fish and ruminants .
- In Australia , when European immigrants brought rabbits there, they bred in such a way that they got out of control and began to eat plants needed by local species to survive. Farmers staged a real rabbit hunt to protect their farms. They also brought cats to protect against rats. Cats turned out to be another problem, as they began to eat local animals.
See also
- Global warming
- Overpopulation
- Ecological catastrophy
Links
- Timofeev Alexander Dmitrievich Semantics of the concepts “Ecological crisis” and “Ecological catastrophe” // Bulletin of the Russian State Pedagogical University named after A.I. Herzen. 2015. No. 176.
- (English) Canada (# 49495)
- Global Warming Said Devastating Aquatic Ecosystems by Brad Bohlander
- (English) “The Ecological Crisis as Part of the Present Multidimensional Crisis and Inclusive Democracy” by Takis Fotopoulos, (International Journal of Inclusive Democracy, vol 3, no 3, June 2007)
- (English) “Myths on the Ecological Crisis” by Takis Fotopoulos
- (English) "Polar Bears Send an 'SOS'" by WWF