Biodiversity is threatened?
Biodiversity is more threatened than it is receding fast. The installation of Man and its means of production and transportation systems in much of the easily accessible areas upset the ecological balance existing. The natural climate fluctuations have always had an impact on species distribution, but since the industrial era the amplitudes of these changes and especially their speed, while pollution and ecosystem fragmentation also increased rapidly, leading to a situation without equivalent in the past.
In recent decades, erosion of biodiversity has been observed almost everywhere, and more than half the surface area of the planet has been significantly altered by humans If there is disagreement on the numbers and time, most scientists believe that the current extinction rate is higher and faster than it has ever been in the past. Most experts believe even that ecology mass extinction is already underway. Several studies show that about one in eight species of known plants are threatened of extinction. Each year, between 17 000 and 100 000 species disappear from our planet, and one fifth of all living species could disappear by 2030. There is consensus that man is the cause, especially by the fragmentation of habitats and / or destruction of ecosystems hosting these species. Without neglecting the evolution of species or even their development over time in given spaces, one can only see in terms of stock losses quantitative and qualitative are especially huge, and that these global last performed regularly and pernicious.
Seas and oceans: a study statistics published in 2006 based on the analysis during four years of data covering a thousand years, for 48 areas of fisheries in the world shows that currently fished species (fish and crustaceans ) could disappear in almost all 2048 without additional measures of preservation. In 2006, 29% of fished species are already on the brink of collapse, forcing an appeal to the largest farms, some of which degrade the environment. The significant loss of marine biodiversity fragile marine ecosystems and consequently the climate and of the entire planet, because the seas and oceans are essential to the biogeochemical cycles, including that of the oxygen.
Some believe that the conversion of ancient ecosystems (or substitute, such as meadows, woods ...) in ecosystems "standard" (eg for example, deforestation followed by monoculture intensive) has even more negative effects on biodiversity that overexploitation of species or degradation of primary ecosystems. Others believe that it is the absence of property rights or rules of access to resources that led to the uncontrolled exploitation of natural resources.
Among these critics, some argue that "unfair inferences" are made and that the current rate of species loss or destruction of rainforests, the coral reefs or mangroves (three kinds of habitat rich in biodiversity) n ' is not sufficient to speak of "mass extinction". Thus, the majority of extinctions or extinctions largest were observed on the islands.
However, besides the theory of landscape ecology predict that it is actually first on the islands that the species are disappearing is precisely a phenomenon insularization écopaysagère that scientists observe in the world. In addition, inventories showed a large amount of cash, if they have not entirely disappeared, they often within decades, given away or melt their populations for most of their former range distribution, which necessarily reduces their genetic diversity. Finally, the acceleration of the virtual disappearance of formerly common fisheries resources is evident, with for example the virtual disappearance of over 200 species of fish in Lake Victoria (compared to 129 species of fresh water only for any l 'Europe), following the introduction of Nile perch in 1954) raises concerns the possibility in a short time, a mass extinction of human origin. The documentary film Darwin's Nightmare (2005) also illustrates this aspect.
In addition to overfishing and overexploitation of forests, deforestation and destruction of ancient forests by forestry, social phenomena as diverse collection (animals, plants, invertebrates, shells, etc.. Or raising domestic rare species collected in nature, or interest in the gold (see gold mining destroying the Amazon for example), or interest in ABP rare (caviar, fur) or the impact of some traditional medicines levying their resources in non-cultured), nature tourism or fishing or hunting and recreational ... aggravate the situation.
Finally, the speed and rate of decline of species at night are poorly monitored and poorly studied, but the phenomenon of light pollution may have been underestimated in its impact in terms of ecological fragmentation of the night environment, yet it is growing steadily and rapidly since the 1950s Last 4 white rhinos in Sumatra are not threatened by pollution but by the value some attach their horns become rare, indicating that give commercial value to a species or an animal, not enough to protect him.
Read Also: Biodiversity and History of Biodiversity