Ecological Crisis

In ecology, a ecological crisis occurs when the medium of Vie of a Espèce or a Population evolves/moves in an unfavourable way to its Survie.

Origin of the ecological crises

An ecological crisis can have one or more origins.

It can be a question of a Environnement whose quality is degraded compared to the needs for the species, following an evolution of the ecological factors abiotiques.
For example, an increase in the local average winter temperature will be able to involve the disappearance of a species requiring a Vernalisation, i.e a need for fresh temperatures for a certain length of time to allow flowering (it could for example be the case of the Mirabelle in Lorraine).
In the same way, a reduction in the Luminosity making for example following multiples volcanic eruptions or with a fall meteoritic, can limit the vegetable biomass considerably, because of the reduction in the effectiveness of the photosynthetic activity (see the assumptions on).

It can also be a question of an environment which becomes unfavourable with the survival of the species (or a population) following an increase in the predatory number of its .
For example, the African elephant is classified species in danger following its intensive Chasse for the Ivoire of its defenses. At the beginning of the 21e century, the number of fish in the oceans is in reduction because of the intensive fishing practiced by the industrial boats.

It can also be a question of an environment which becomes unfavourable following an increase in the competition interspecific (between two species) or intraspecific (between two races of the same species) for the space or the sources of Nourriture.
For example, of the invasive species, such as Caulerpa taxifolia at sea the Mediterranean involves gradually the disappearance of the species locales.
Another example concerns what was called écocide with the Vietnam: at the time of the armed conflict between the United States and the Vietnam of North, American used a defoliant, the orange Agent (container of the Dioxine), in the objective to destroy, the forest in which the combatants hid, or the rice plantations which nourished them. The dioxane poured at the time accumulated in the trophic chains and is still responsible, 40 years later, of the birth of abnormal children, without members, even without cranium or brain. The weedkillers used would have also destroyed 2 and 500.000 hectare hectare of forest million of Mangrove S replaced by savannas.

Lastly, it can also be a question of a situation which becomes unfavourable with the quality of life of the species (or the population) following a too strong increase in the number of individuals, which imposes strong a pressure on its environment of life.

The extinction of the species

Local crises and total crises

The ecological crises can be local or total. In the case of a local crisis, only an ecosystem will be touched. If the species is endemic, the ecological crisis will be able to involve its disappearance. It is for example the case of several Hominidé S, like the Grand monkey, of which there remain nothing any more but some survivors.

A local ecological crisis touches a certain geographical area, of reduced size, example a Fleuve, a Mer, a island, a écorégion. It has negative consequences for a part or totality of the species living in this area. An example of local crisis can be an oil slick, such as that due to the shipwreck of the Erika, or an incident in a chemical plant, such as the Catastrophe of Bhopal.

A total ecological crisis touches the whole of the Biosphère, and potentially the whole of the species. Among the most quoted examples is that relating to the risk of Climate warming related to the Greenhouse effect, that of the hole of the Couche of ozone related to the CFC emissions or the acid rains related to the emissions of Soufre.

The phenomenon of total crisis is not new, however it was before only related to the modifications of ecological factors abiotic (for example, reduction in the average temperature during the Ice Age of quaternary).

What is more recent however, is the impact due to only one and single species on the biosphere: the mankind. The man, predatory omnivorous, was a simple element a long time among the others within the natural ecosystems. Thanks to his technological acquisitions and with a strong increase in population, the man is the only species whose activity has a major influence on its medium of life. The beginning of this influence dates from the beginnings of agriculture, with the Neolithic era. Whereas he was neglected a long time by the ecologists, human ecology regards now the man as a ecological Facteur new and studies the impact of its activity on its environment of life.

The mankind is different from the other alive species with various titles:

the species migrated and colonized practically all the continents. Except for rare exceptions (extremely cold or very arid mediums), the man spread himself on the totality of terrestrial surface.

Anthropisation : the man modifies his environment of life voluntarily and consciously (with agriculture, the man modifies the landscape, makes almost irréversiblement move back the forest to build cities in the place; he replaces certain communities of plants by artificial ecosystems, the fields, or the meadows).

the man disturbs balances of the biosphere and the Biodiversité by the means of its agricultural activity and industrial (for example while releasing from great quantities of phosphates, in the form of manure or of detergents, phosphates responsible for the Eutrophisation of certain aquatic environments);

the man is the only species whose activity in a point of the sphere can have consequences in a completely different point (for example, the emission of the Gaz to greenhouse effect by the developed countries is considered to be responsible for a certain part of the climate warming, which could itself lead to the disappearance of Bangladesh; to also see the passage of the radioactive cloud coming from the explosion of the power station of Tchernobyl above a good part of Europe which is responsible for contamination still today).

If the anthropic activity is considered to be mainly today responsible for what it became current to call “the total ecological crisis”, the mankind is also the only species which acts consciously and deliberately to try to restore certain total balances (for example, by the means of international protocols, such as the Protocole of Kyoto). For many specialists, the maintenance of the biodiversity is the indispensable condition for the survival of the biosphere, from where multiplication of conferences relating to the biodiversity.

Consequences of the ecological crises

Certain species colonized totality (or almost) terrestrial sphere, for example, the species human, the ant, the moustique.
Other species do not live on the totality of the terrestrial sphere but are however represented by a great number of populations disseminated in similar ecosystems; it is the case of the oak which exist in practically all the zones tempérées.
A big number of species are represented only by one small number of populations, because rather strong climatic requirements; it is the case for example seal (for recall, a population is one together of individuals belonging all to the same species, and living at the same place at the same time).
Lastly, the species known as endemic (an endemic species with a place is a species which lives only at this place) is not represented by only one and single population. The disappearance of this population (for example, continuation with the destruction of its single medium of life) the disappearance of the species will involve. Destruction of a high area with endemism (comprising a great number of endemic species) the extinction will cause of a significant number of species and is thus particularly important for the Conservation.

A local ecological crisis can have as a consequence the death of many individuals, the disappearance of a population, even of a species if this one were endemic. According to the species and its role in the ecosystem, this disappearance can involve a more or less important rupture in the food chain and to have a variable impact on the survival of the other living beings.

In the case of a total crisis, the consequences can be much more important, since certain extinctions saw the disappearance of more than 90% of the species. However, it should be noted that disappearance of certain species, such as the dinosaurs, by releasing an ecological niche, have license the development and the diversification of the mammals. An ecological crisis thus has paradoxically supported the biodiversity.

Sometimes, an ecological crisis can be a specific and reversible phenomenon on an ecosystem scale. But more generally, the ecological crises have a longer-term major impact. Indeed, it acts rather of a succession of events which induce the ones the others, to a certain point of rupture. With to start from this stage, which can correspond to dead of many individuals and the extinction of one or more species, the flashback with the preceding state of stability is not possible any more, and a new state will be set up gradually.

If an ecological crisis can be at the origin of extinction, it can also reduce the quality of life of the individuals remaining in life. Thus, even if the diversity of the human population is sometimes considered threatened (see in particular native-born people), little agree to consider the disappearance of the mankind in the short run. However, epidemic diseases, famines, impact on the health of the deterioration of the quality of the air, food crises (see also Biosûreté or the Food safety), the disappearance of the mediums of life (see écoréfugié S), the accumulation of toxic waste not dégradables, threats of disappearances species headlights (the such large monkeys, the panda, the whale)… are also factors impacting also the Wellbeing of people (see also ethical).

Some examples

The ecological crises are not a recent phenomenon. The geologists highlighted the occurrence of multiple total crises having led to massive extinctions of Espèce S. Of the varied assumptions could explain these crises, the fall of meteors, modifications of the solar activity, recrudescence of the volcanic activity, continental drift, the variations of the Eustatisme, etc These biological crises in particular make it possible to establish the large cuts of the geological time scale.

More recent, the European ecological crisis of XIVe century leads to a considerable reduction of the human population. This crisis occurs whereas Europe had arrived at the saturation of its Capacity load, taking into account the known agrarian techniques (the Araire, the Brûlis, the common grazing land) and taking into account the taking away by the inactive lords of the time (Féodalisme). In this situation of limitation of the food resources necessary to a population in full expansion, the arrival of the Great Plague about 1346, involved the disappearance moreover of the third of the European population. The diffusion of the microbe of the plague was supported by the maritime exchanges and the urban development of the time. Following the reduction in the population, the European load capacity is become again sufficient and the crisis modified the techniques of production of the time, with the use of the plow out of iron and the mixed-farming breeding (for which the waste of an activity it dung becomes the input of another - manure).

With the beginning of the 21e century, many specialists estimate that a major ecological crisis is occurring. The advanced arguments are:

atmospheric evolutions

One of the most quoted problems is that relating to the risk of Climate warming related to the greenhouse effect, caused by the strong increase in the Carbon dioxide and the Méthane in the atmosphere. A total warming could involve the flood of the Asian deltas (see also écoréfugié S), the multiplication of extreme climatic phenomena and the evolution of the nature and quantity of the food resources following the impacts on the agricultural activity.

Among the other total problems, one can quote the hole of the Couche of ozone (having led to the prohibition of the use of the Chlorofluorocarbone S (CFC) and other halogenous gases used in the sprays aerosol and the systems of refrigeration) or the acid rains related to the emissions of Soufre.

The industry of transport and the car carries a share of responsibilities in volume for these emissions for Gaz to greenhouse effect.

See also: environmental Automobile#Impact, Environmental impact of auto industry

degradation, even the disappearance of certain habitats

In many regions, original nature was replaced by a medium modified by the man. Thus, in Europe, the major part of the forests hercyniennes was cleared and replaced by intensive cultures, arranged artificial lakes, planted moors. Part of the Asia (Is China, India, Southeast Asia…) as well as the the Middle East also lost most of their original habitat since centuries, even of the millenia.

In other countries with fragile ground, such as Amazonia, the deforestation of the Amazon forest at end of culture, frequently leads to situations of Désertification. Indeed, the Amazonian grounds are rather poor and regularly abandoned 3 to 4 years after grubbing.

Salt-water marshes were eliminated within the framework from the fight against the mosquitos and for the tourist development .

The Catastrophe of Tchernobyl in 1986 was at the origin of the abandonment of arable large surfaces, solid masses displacement of the populations, Cancer S more in the local populations and of died of very many animals. Lastly, of the maritime catastrophes recurring leads to the pollution of the marine medium and the littorals during degasifications or droppings of Hydrocarbure S (see Amoco Cadiz for example).

evolution of the availability and water quality

Among the most pressing questions those are reproduced bearing on the availability out of water and more particularly in Drinking water. The Démographie which gallops is in the beginning, locally, of Surpopulation, it involves on the one hand increasing requirements out of water (also related to an increase in the quality of the life) and on the other hand increasing difficulties to manage the Pollution S of water which cannot be any more taken into account by the natural environment.

evolution of the production of waste

In a similar way the increasing difficulty of the management of the Déchet S arises, in particular in the countries Industrie ls. The last decades of the 20th century saw the increase in the number of waste, of which in particular toxic waste (such as dioxane), ultimate waste of the nuclear industry or more simply of great quantities of not-biodegradable waste. This waste can be at the origin of cancers in the populations. In certain countries, gigantic refuse tips developed.

Modification of the competitions between species

Another consequence of the development of the human presence on the sphere is the influence of the introduction of exotic species, entering in competition with the local species (such as small the Tortue of Florida offered to the children, then slackened in nature, the alga Caulerpa taxifolia in the Mediterranean, or the Invasion of the rabbits in Australia). These introductions often involuntary, are disseminated by boats or planes. Some also fear the influence which the setting in culture of genetically modified plants could have.

multiplication of crises relative to biosûreté

An indicator of the generalized advent of an ecological crisis relates to the awakening of the multiplication of more or less local crises relating to the Biosûreté: among which the mad cow, oil slicks, appearance of the AIDS, that of the Avian flu, and increase in the cases of Cancer related to the environmental exposure. This awakening does not escape media phenomena related to the Alarmisme (it is for example the case of the advertisements of the risks médiatisant the avian flu and its consequences with the autumn 2005, extremely fortunately not followed in the facts).

the high rate/rhythm of disappearance of the species

Beyond the observation of the evolution of the characteristics of the biosphere, the experts estimate that the disappearance of species currently occurs at very high intervals. The destruction of the natural environments, accompanied by the impoverishment of the soil had an impact on the Biodiversité (flora and fauna), involving the disappearance or the rarefaction of many species, such as the wolf, the brown Ours, the Bison, the lynx. However, other species could thrive in the ecological news niches.

The development of the Ville S.A. reduces the surfaces of distribution of the species, but could support others of them (presence of parks and gardens). Certain animal species made profitable the existence of the stations, the churches, the undergrounds. However, from many animals disappear crushed on the highways, drowned in the channels, or struck against panes.

Causes

The causes of the current ecological crisis seem to be the product of the development of several factors, of which it is difficult to establish and to date the Cause S. It is however acquired that the activity of the mankind is the first explanation. The impact would have strongly increased, on the one hand because of the increase in the total population (see also demographic Transition), on the other hand because of the economic development and industrialist of the last decades of the 20th century (see also decrease and Sustainable development).

According to Jean Bastaire, the total ecological crisis would find its origin in the philosophy of Descartes, according to which the man was “to go as Master and owner of nature” ( Discourse on Method , Sixth part) (see also ecological Crise and theology of Creation).

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