Ecological crisis

An ecological or environmental crises 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
This section is an excerpt from Effects of climate change on ecosystems.[edit]
Rainforest ecosystems are rich in biodiversity. This is the Gambia River in Senegal's Niokolo-Koba National Park.
Climate change has adversely affected terrestrial[1] and marine[2] ecosystems, including tundras,[3] mangroves, coral reefs, and caves.[4] Increasing global temperature, more frequent occurrence of extreme weather,[5] and rising sea level[6] are examples of the most impactful effects of climate change. Possible consequences of these effects include species decline and extinction and overall significant loss of biodiversity, change within ecosystems, increased prevalence of invasive species,[7] loss of habitats, forests converting from carbon sinks to carbon sources, ocean acidification, disruption of the water cycle, increased occurrence and severity of natural disasters like wildfires and flooding, and lasting effects on species adaptation.

Biodiversity extinction
This section is an excerpt from Biodiversity loss.[edit]
Summary of major biodiversity-related environmental-change categories 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.[8]

Biodiversity loss includes the worldwide extinction of different species, as well as the local reduction or loss of species in a certain habitat, resulting in a loss of biological diversity. The latter phenomenon can be temporary or permanent, depending on whether the environmental degradation that leads to the loss is reversible through ecological restoration/ecological resilience or effectively permanent (e.g. through land loss). The current global extinction (frequently called the sixth mass extinction or Anthropocene extinction), has resulted in a biodiversity crisis being driven by human activities which push beyond the planetary boundaries and so far has proven irreversible.[8][9][10]

The main direct threats to conservation (and thus causes for biodiversity loss) fall in eleven categories: Residential and commercial development; farming activities; energy production and mining; transportation and service corridors; biological resource usages; human intrusions and activities that alter, destroy, disturb habitats and species from exhibiting natural behaviors; natural system modification; invasive and problematic species, pathogens and genes; pollution; catastrophic geological events, climate change, and so on.[11]

Numerous scientists and the IPBES Global Assessment Report on Biodiversity and Ecosystem Services assert that human population growth and overconsumption are the primary factors in this decline.[12][13][14][15][16] However other scientists have criticized this, 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, due to country wealth disparities.[17]

Climate change is another threat to global biodiversity.[18][19] For example, coral reefs – which are biodiversity hotspots – will be lost within the century if global warming continues at the current rate.[20][21] However, habitat destruction e.g. for the expansion of agriculture, is currently the more significant driver of contemporary biodiversity loss, not climate change.[22][23]

International environmental organizations have been campaigning to prevent biodiversity loss for decades, public health officials have integrated it into the One Health approach to public health practice, and increasingly preservation of biodiversity is part of international policy, as part of the response to the Triple planetary crisis. For example, the UN Convention on Biological Diversity is focused on preventing biodiversity loss and proactive conservation of wild areas. The international commitment and goals for this work is currently embodied by Sustainable Development Goal 15 "Life on Land" and Sustainable Development Goal 14 "Life Below Water". However, the United Nations Environment Programme report on "Making Peace with Nature" released in 2020 found that most of these efforts had failed to meet their international goals.[24] Of the 20 biodiversity goals laid out by the Aichi Biodiversity Targets in 2010, only 6 were "partially achieved" by the deadline of 2020.[25][26]

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
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  2. "Summary for Policymakers — Special Report on the Ocean and Cryosphere in a Changing Climate". Retrieved 2019-12-23.
  3. Skre, Oddvar; Baxter, Robert; Crawford, Robert M. M.; Callaghan, Terry V.; Fedorkov, Alexey (2002). "How Will the Tundra-Taiga Interface Respond to Climate Change?". Ambio. Spec No 12: 37–46. ISSN 0044-7447. JSTOR 25094574. PMID 12374058.
  4. Mammola, Stefano; Goodacre, Sara L.; Isaia, Marco (January 2018). "Climate change may drive cave spiders to extinction". Ecography. 41 (1): 233–243. doi:10.1111/ecog.02902. hdl:2318/1623725. S2CID 55362100.
  5. Geremy, Taylor; Christopher M. Belusic; Danijel Guichard; Francoise Parker; Douglas J. Vischel; Theo Bock; Olivier Harris; Phil P. Janicot; Serge Klein; Cornelia Panthou (2017-04-27). Frequency of extreme Sahelian storms tripled since 1982 in satellite observations. Nature Publishing Group. OCLC 990335453.
  6. Priestley, Rebecca; Heine, Zoë; Milfont, Taciano L (2021-07-14). "Public understanding of climate change-related sea-level rise". PLOS ONE. 16 (7): e0254348. Bibcode:2021PLoSO..1654348P. doi:10.1371/journal.pone.0254348. hdl:10289/14493. PMC 8270426. PMID 34242339. S2CID 243117767.
  7. "How does climate change affect the challenge of invasive species? | U.S. Geological Survey". www.usgs.gov.
  8. Bradshaw, Corey J. A.; Ehrlich, Paul R.; Beattie, Andrew; Ceballos, Gerardo; Crist, Eileen; Diamond, Joan; Dirzo, Rodolfo; Ehrlich, Anne H.; Harte, John; Harte, Mary Ellen; Pyke, Graham; Raven, Peter H.; Ripple, William J.; Saltré, Frédérik; Turnbull, Christine; Wackernagel, Mathis; Blumstein, Daniel T. (2021). "Underestimating the Challenges of Avoiding a Ghastly Future". Frontiers in Conservation Science. 1. doi:10.3389/fcosc.2020.615419.
  9. Ripple WJ, Wolf C, Newsome TM, Galetti M, Alamgir M, Crist E, Mahmoud MI, Laurance WF (13 November 2017). "World Scientists' Warning to Humanity: A Second Notice". BioScience. 67 (12): 1026–1028. doi:10.1093/biosci/bix125. 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.
  10. Cowie RH, Bouchet P, Fontaine B (April 2022). "The Sixth Mass Extinction: fact, fiction or speculation?". Biological Reviews of the Cambridge Philosophical Society. 97 (2): 640–663. doi:10.1111/brv.12816. PMC 9786292. PMID 35014169. S2CID 245889833.
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  12. Stokstad, Erik (6 May 2019). "Landmark analysis documents the alarming global decline of nature". Science. 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.)
  13. Pimm SL, Jenkins CN, Abell R, Brooks TM, Gittleman JL, Joppa LN, et al. (May 2014). "The biodiversity of species and their rates of extinction, distribution, and protection". Science. 344 (6187): 1246752. doi:10.1126/science.1246752. PMID 24876501. S2CID 206552746. The overarching driver of species extinction is human population growth and increasing per capita consumption.
  14. Cafaro, Philip; Hansson, Pernilla; Götmark, Frank (August 2022). "Overpopulation is a major cause of biodiversity loss and smaller human populations are necessary to preserve what is left" (PDF). Biological Conservation. 272. 109646. doi:10.1016/j.biocon.2022.109646. ISSN 0006-3207. S2CID 250185617. 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.
  15. Crist, Eileen; Mora, Camilo; Engelman, Robert (21 April 2017). "The interaction of human population, food production, and biodiversity protection". Science. 356 (6335): 260–264. Bibcode:2017Sci...356..260C. doi:10.1126/science.aal2011. PMID 28428391. 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.
  16. Ceballos, Gerardo; Ehrlich, Paul R. (2023). "Mutilation of the tree of life via mass extinction of animal genera". Proceedings of the National Academy of Sciences of the United States of America. 120 (39): e2306987120. doi:10.1073/pnas.2306987120. 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.
  17. Hughes, Alice C.; Tougeron, Kévin; Martin, Dominic A.; Menga, Filippo; Rosado, Bruno H. P.; Villasante, Sebastian; Madgulkar, Shweta; Gonçalves, Fernando; Geneletti, Davide; Diele-Viegas, Luisa Maria; Berger, Sebastian; Colla, Sheila R.; de Andrade Kamimura, Vitor; Caggiano, Holly; Melo, Felipe (2023-01-01). "Smaller human populations are neither a necessary nor sufficient condition for biodiversity conservation". Biological Conservation. 277: 109841. doi:10.1016/j.biocon.2022.109841. 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.
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  22. Ketcham, Christopher (December 3, 2022). "Addressing Climate Change Will Not "Save the Planet"". The Intercept. Retrieved December 8, 2022.
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Further reading
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