Ecological crisis

Source: Wikipedia, the free encyclopedia.

An ecological or environmental crisis occurs when changes to the environment of a species or population destabilizes its continued survival. Some of the important causes include:

  • Degradation of an abiotic
    ecological factor
    (for example, increase of temperature, less significant rainfalls)
  • Increased pressures from predation
  • Rise in the number of individuals (i.e. overpopulation)

The

evolutionary theory of punctuated equilibrium
sees infrequent ecological crises as a potential driver of rapid evolution.

Because of the impact of humans on the natural environment in the recent geological period, the term ecological crisis is often applied to environmental issues caused by human civilizations such as: the climate crisis, biodiversity loss and plastic pollution which have emerged as major global challenges during the first few decades of the 21st century.

Examples

Crises caused by abiotic factors

Climate change is starting to have major impacts on ecosystems. With

global temperature rising
, there is a decrease in snow-fall, and sea levels are rising. Ecosystems will change or evolve to cope with the increase in temperature. Consequently, many species are being driven out of their habitats.

Polar bears are being threatened. They need ice for hunting seals, their primary prey. However, the ice caps are melting, making their hunting periods shorter each year. As a result, the polar bears are not developing enough fat for the winter; therefore, they are not able to reproduce at a healthy rate.

Fresh water and wetland ecosystems are dealing with extreme effects of the increase of temperature. The climate change could be devastating to salmon and trout and to other aquatic life. The increase in temperature will disrupt the current life patterns of the salmon and trout. The cold-water fish will eventually leave their natural geographical range to live in cooler waters by migrating to higher elevations.

While many species have been able to adapt to the new conditions by moving their range further towards the poles, other species are not as fortunate. The option to move is not available for polar bears and for some aquatic life.

Climate change

{{Excerpt|Effects of climate change on biomes hshgdnsj }

Biodiversity extinction

This section is an excerpt from Biodiversity loss.[edit]


Summary of major environmental-change categories that cause biodiversity loss. The data is expressed as a percentage of human-driven change (in red) relative to baseline (blue). Red indicates the percentage of the category that is damaged, lost, or otherwise affected, whereas blue indicates the percentage that is intact, remaining, or otherwise unaffected.[1]

invasive species[7] and climate change.[4]

Many scientists, along with the

growing human population because this leads to human overpopulation and excessive consumption.[8][9][10][11][12] Others disagree, saying that loss of habitat is caused mainly by "the growth of commodities for export" and that population has very little to do with overall consumption. More important are wealth disparities between or within countries.[13]

Climate change is another threat to global biodiversity.[14][15] For example, coral reefs—which are biodiversity hotspots—will be lost by the year 2100 if global warming continues at the current rate.[16][17] Still, it is the general habitat destruction (often for expansion of agriculture), not climate change, that is currently the bigger driver of biodiversity loss.[18][19] Invasive species and other disturbances have become more common in forests in the last several decades. These tend to be directly or indirectly connected to climate change and can cause a deterioration of forest ecosystems.[20][21]

Deforestation also plays a large role in biodiversity loss. More than half of the worlds biodiversity is hosted in tropical rainforest.[22] Regions that are subjected to exponential loss of biodiversity are referred to as "hotspots", since 1988 the hotspots increased from 10 to 34, of the total 34 hotspots currently present, 16 of them are in tropical regions.[23] Researchers have noted that only 2.3% of the world is covered with biodiversity loss hotspots, even though only a small percentage of the world is covered in hotspots, it host a large fraction (50%) of vascular plant species.[24]

Groups that care about the environment have been working for many years to stop the decrease in biodiversity. Nowadays, many global policies include activities to stop biodiversity loss. For example, the

Aichi Biodiversity Targets in 2010, only six were "partially achieved" by 2020.[26][27]

This ongoing global extinction is also called the holocene extinction or sixth mass extinction.

Animal overpopulation

Main article: Overpopulation

In the wilderness, the problem of

animal overpopulation
is solved by predators. Predators tend to look for signs of weakness in their prey, and therefore usually first eat the old or sick animals. This has the side effects of ensuring a strong stock among the survivors and controlling the population.

In the absence of predators, animal species are bound by the resources they can find in their environment, but this does not necessarily control overpopulation. In fact, an abundant supply of resources can produce a population boom that ends up with more individuals than the environment can support. In this case, starvation, thirst, and sometimes violent competition for scarce resources may effect a sharp reduction in population, and in a very short lapse, a population crash. Lemmings, as well as other less popular species of rodents, are known to have such cycles of rapid population growth and subsequent decrease.

In an ideal setting, when animal populations grow, so do the number of predators that feed on that particular animal. Animals that have birth defects or weak genes (such as the runt of the litter) also die off, unable to compete over food with stronger, healthier animals.

In reality, an animal that is not native to an environment may have advantages over the native ones, such being unsuitable for the local predators. If left uncontrolled, such an animal can quickly overpopulate and ultimately

destroy its environment
.

Examples of animal overpopulation caused by introduction of a foreign species abound.

  • In the Argentine Patagonia, for example, European species such as the trout and the deer were introduced into the local streams and forests, respectively, and quickly became a plague, competing with and sometimes driving away the local species of fish and ruminants.
  • In
    Australia
    , when rabbits were introduced (unwillingly) by European immigrants, they bred out of control and ate the plants that other native animals needed to survive. Farmers hunted the rabbits to reduce their population and prevent the damage the rabbits did to the crops. They also brought cats to guard against rabbits and rats. These cats created another problem, since they became predators of local species.

More examples

Some common examples of ecological crises are:

See also

References

  1. ^
    doi:10.3389/fcosc.2020.615419
    .
  2. hdl:11336/71342
    . Moreover, we have unleashed a mass extinction event, the sixth in roughly 540 million years, wherein many current life forms could be annihilated or at least committed to extinction by the end of this century.
  3. S2CID 245889833
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  4. ^ a b "Global Biodiversity Outlook 3". Convention on Biological Diversity. 2010. Archived from the original on May 19, 2022. Retrieved January 24, 2017.
  5. S2CID 3642597. Archived
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  8. doi:10.1126/science.aax9287
    . For the first time at a global scale, the report has ranked the causes of damage. Topping the list, changes in land use—principally agriculture—that have destroyed habitat. Second, hunting and other kinds of exploitation. These are followed by climate change, pollution, and invasive species, which are being spread by trade and other activities. Climate change will likely overtake the other threats in the next decades, the authors note. Driving these threats are the growing human population, which has doubled since 1970 to 7.6 billion, and consumption. (Per capita of use of materials is up 15% over the past 5 decades.)
  9. S2CID 206552746
    . The overarching driver of species extinction is human population growth and increasing per capita consumption.
  10. S2CID 250185617. Archived
    (PDF) from the original on December 8, 2023. Retrieved December 25, 2022. Conservation biologists standardly list five main direct drivers of biodiversity loss: habitat loss, overexploitation of species, pollution, invasive species, and climate change. The Global Assessment Report on Biodiversity and Ecosystem Services found that in recent decades habitat loss was the leading cause of terrestrial biodiversity loss, while overexploitation (overfishing) was the most important cause of marine losses (IPBES, 2019). All five direct drivers are important, on land and at sea, and all are made worse by larger and denser human populations.
  11. S2CID 12770178
    . Retrieved 2 January 2023. Research suggests that the scale of human population and the current pace of its growth contribute substantially to the loss of biological diversity. Although technological change and unequal consumption inextricably mingle with demographic impacts on the environment, the needs of all human beings—especially for food—imply that projected population growth will undermine protection of the natural world.
  12. PMID 37722053
    . Current generic extinction rates will likely greatly accelerate in the next few decades due to drivers accompanying the growth and consumption of the human enterprise such as habitat destruction, illegal trade, and climate disruption.
  13. ISSN 0006-3207
    . Through examining the drivers of biodiversity loss in highly biodiverse countries, we show that it is not population driving the loss of habitats, but rather the growth of commodities for export, particularly soybean and oil-palm, primarily for livestock feed or biofuel consumption in higher income economies.
  14. ^ "Climate change and biodiversity" (PDF). Intergovernmental Panel on Climate Change. 2005. Archived from the original (PDF) on 5 February 2018. Retrieved 12 June 2012.
  15. ^ Kannan, R.; James, D. A. (2009). "Effects of climate change on global biodiversity: a review of key literature" (PDF). Tropical Ecology. 50 (1): 31–39. Archived from the original (PDF) on 15 April 2021. Retrieved 21 May 2014.
  16. ^ "Climate change, reefs and the Coral Triangle". wwf.panda.org. Archived from the original on May 2, 2018. Retrieved 9 November 2015.
  17. ^ Aldred, Jessica (2 July 2014). "Caribbean coral reefs 'will be lost within 20 years' without protection". The Guardian. Archived from the original on October 20, 2022. Retrieved 9 November 2015.
  18. ^ Ketcham, Christopher (December 3, 2022). "Addressing Climate Change Will Not "Save the Planet"". The Intercept. Archived from the original on February 18, 2024. Retrieved December 8, 2022.
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  20. ISBN 978-92-861-5403-4. Archived
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  21. S2CID 234260720
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  23. PMID 16909582. Archived
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  24. PMID 16909582. Archived
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  25. ^ United Nations Environment Programme (2021). Making Peace with Nature: A scientific blueprint to tackle the climate, biodiversity and pollution emergencies. Nairobi: United Nations. Archived from the original on March 23, 2021. Retrieved March 9, 2021.
  26. ^ Cohen L (September 15, 2020). "More than 150 countries made a plan to preserve biodiversity a decade ago. A new report says they mostly failed". CBS News. Archived from the original on May 15, 2022. Retrieved September 16, 2020.
  27. ^ "Global Biodiversity Outlook 5". Convention on Biological Diversity. Archived from the original on October 6, 2021. Retrieved 2023-03-23.
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  29. ^ "Wildlife defies Chernobyl radiation". 20 April 2006.

Further reading

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