The carrying capacity of a biological species in an environment is the maximum population size of the environment indefinitely sustainably, given the food, habitat , water , and other necessities available in the environment. In population biology , carrying capacity is defined as the environment ’s maximum load, [1] qui is different from the concept of equilibrium population. Its effects on population dynamics may be approximated in a logistic model , with this simplification ignores the possibility ofovershoot which real systems may exhibit.

Carrying capacity was originally used to determine the number of animals that could be destroyed. Later, the idea was expanded to more complex populations, like humans. [2] For the human population , more complex variables such as sanitation and medical care are sometimes considered as part of the necessary establishment. As population density increases, birth rate often increases and death ratetypically decreases. The difference between the birth rate and the death rate is the „natural increase“. The carrying capacity could support a positive increase. Thus, the carrying capacity is the number of individuals in the environment and their impact on the environment. Below carrying capacity, typically increase populations, while above, they typically decrease. A factor that keeps population size at equilibrium is known as a regulating factor . Population size decreases Above carrying capacity due to a Range of factors DEPENDING on the species Concerned, purpose can include Insufficient space , food supply, sunlight gold . The carrying capacity of an environment may vary for a range of factors including: food availability , water supply , environmental conditions and living space. The origins of the term „carrying capacity“ are uncertain, with variously Researchers Stating That It Was used „in the context of international shipping “ [3] or That It was first used During 19th-century laboratory experiments with micro-organisms. [4] A recent review finds the first use of the term in an 1845 report by the US Secretary of State to the US Senate . [3]

Humans

Several estimates of the carrying capacity have been made with a wide range of population numbers. A 2001 report said that two-thirds of the forecast fall in the range of 4 billion to 16 billion with unspecified standard errors, with a median of about 10 billion. [5] More recent Estimates are much lower, PARTICULARLY if non-renewable resource depletion and Increased consumption are regarded. [6] [7] Changes in habitat quality or human behavior at any time. In the view of Paul and Anne Ehrlich , „for earth as a whole (including those parts of it we call Australia and the United States),“[8]

The implementation of the concept of carrying capacity for the human population has-been Criticized for not successfully capturing the multi-layered processes entre humans and the environment, qui-have a kind of fluidity and non-equilibrium , and for being white Sometimes employed in a blame- the-victim framework. [9]

Supporters of the concept argues that the idea of ​​a limited carrying capacity is just as validated to humans as when applied to any other species. Animal population size, living standards, and resource depletion vary, but the concept of carrying capacity still applies. The number of people is not the only factor in the carrying capacity of Earth. Waste and over-consumption , especially by wealthy and near-wealthy nations, are also putting significant strain on the environment together with human overpopulation . Population and consumption together appear at the heart of many human problems. [10] [8] Some of These issues-have-been Studied by computer simulation models Such As World3. When scientists talk about global change today, they are usually referred to human-induced changes in the environment of sufficient magnitude to reduce the carrying capacity of Earth (as opposed to local or regional areas) to support organisms, especially Homo sapiens. [11]

Factors that govern carrying capacity

Some aspects of a system of carrying supplies of food , water , raw materials, and other sources. In addition, there are other factors that may be less intuitive or intuitive in nature, such as ever-increasing and / or ever-accumulating levels of wastes , damage , and / or eradication of essential components of any complex functioning. system. Eradication of, for example, large or critical portions of any complex system(envision a space vehicle, for instance, or an airplane, or an automobile, or computer code, or the body components of a living vertebrate). (En français) As an example of these factors, the „carrying capacity“ of a complex system such as airspace damage, destroy, or eradicate parts, doors , windows, wings, engine parts, fuel, and oil, and so forth.) Thus, we have global scale, food and similar resources can affect planetary carrying capacity to some extent human passengers do not dismantle, eradicate, or otherwise destroy criticalbiospheric life-support capacities for essential processes of self-maintenance, self-perpetuation , and self-repair .

Thus, carrying capacity interpretations that focus only on resource limitations alone (such as food) may neglect larger functional factors. If the numbers are not significant, the calculation is fairly accurate. If the quantity of food is invariably equal to the „Y“ amount, carrying capacity has been reached. Humans, with the need to enhance their reproductive success (see Richard Dawkins‘ The Selfish Gene [ verification needed ]), understand that food supply can vary and also other factors in the environment. A house, for example, might be one of those things. Over time, monetary transactions and local production. However, there are also many thousands of miles away. For example, carbon dioxide from an automobile travels to the upper atmosphere. This led Paul R. Ehrlich to develop the I = PAT equation. [12]

I = P  ∙  A  ∙  T

where:

I is the impact on the environment
P is the population number
A is the consumption per capita (affluence)
T is the technology factor
This is a graph of the population due to the logistic curve model. When the population is above the carrying capacity it is decreasing.

An important model related to carrying capacity (K), is the logistic growth curve. The logistic growth curve depicts a more realistic version of the population growth rate, available resources, and the carrying capacity are inter-connected. As illustrated in the logistic growth curve model, when the population is over-population increases and so does the growth rate. However, as population size is increasing, the growth rate decreases and population starts to be at K. This model is based on the assumption that it does not change. One thing to keep in mind, however, is that carrying capacity of a population can increase or decrease it. Par exemple,[13]

Technology can play a role in the dynamics of carrying capacity and while it can sometimes be positive, [14] in other cases its influence can be problematic. For example, it has been suggested that the Neolithic revolution has increased the carrying capacity of the world relative to humans through the invention of agriculture. In a similar way, viewed from the perspective of foods, the use of fossil fuels has been artificially increasing the carrying capacity of the world by the use of stored sunlight, even though that food production does not guarantee the capacity of the Earth’s climatic and biosphericlife-support systems withstand the damage and wastes arising from such fossil fuels. However, such interpretations presume the continued and uninterrupted functioning of all other critical components of the global system. It has also been suggested that other environmental factors include: polders , fertilizer , composting , greenhouses , land claims , and fish farming . quote needed ]In an adverse way, however, many technologies enable economic entities and individual humans to inflict more eradication and eradication, far more quickly and efficiently on a wider-scale than ever. Examples include machine guns, chainsaws, earth-movers, and the capacity of industrialized fishing fleets to capture and harvest fish species faster than the fish themselves can reproduce examples of such problematic outcomes of technology.

Agricultural capability on Earth expanded in the last quarter of the 20th century. But now there are many projections of a continuation of the world of agricultural capability (and hence carrying capacity) which began in the 1990s. Most conspicuously, China’s food production is forecast to decline by the last half of the 21st century, as China’s population could expand to about 1.5 billion people by the year 2050. [ 15] This reduction in China’s agricultural capability (as in other world regions) is largely due to the world water crisis and especially to mining groundwater beyond sustainable yield, which has been happening in China since the mid-20th century.[16]

Lester Brown of the Earth Policy Institute , said: „It would take 1.5 Earths to sustain our present level of consumption, Environmentally, the world is in an overshoot mode.“ [17]

Ecological footprint

One way to estimate human demand compared to ecosystem’s carrying capacity is “ ecological footprint “ accounting. Ecological footprint accounting provides empirical, non-speculative assessments of the past. It compares historic regeneration rates, biocapacity , against historical human demand , ecological footprint , in the same year. [18] [19] One result shows that humanity’s demand footprint in 1999 exceeded the planet’s bio-capacity by> 20%. [18]However, this measurement does not take into account the depletion of the fossil fuels, „which would result in a carbon Footprint many times higher than the current calculation.“ [20]

There is also concern about the ability of countries around the globe to decrease and maintain their ecological footprints. Holden and Linnerud, Paris, France, Paris, France in 2007. Possible answers to the question of where we are trying to achieve sustainability and sustainability. According to Figure 1 diagram, the United States had the largest ecological foot print by capita along with Norway, Sweden, and Austria, in comparison to Cuba, Bangladesh, and Korea. [21]

See also

  • Tourism carrying capacity
  • Arable land
  • Asymmetry Principle
  • Biocapacity
  • Ecological economics
  • Ecological footprint
  • Effects of global warming
  • Environmental space
  • List of countries by fertility rate
  • Over-consumption
  • overpopulation
  • Inflection point
  • Optimum population
  • Overpopulation in wild animals
  • Overshoot (ecology)
  • Population
  • Population ecology
  • Population growth
  • Principles of Intelligent Urbanism
  • r / K selection theory
  • Simon-Ehrlich wager
  • Thomas Malthus
  • Toxic capacity
  • Aftermath: Population Overload disambiguation needed ]

Footnotes

  1. Jump up^ Hui, C (2006). „Carrying capacity, population equilibrium, and environment’s maximal load“. Ecological Modeling . 192 : 317-320. doi :10.1016 / j.ecolmodel.2005.07.001 .
  2. Jump up^ „Carrying Capacity“ . The Sustainable Scale Project . Retrieved 16 February 2017 .
  3. ^ Jump up to:b Sayre, NF (2008). „The Genesis, History, and Limits of Carrying Capacity“ . Annals of the Association of American Geographers . 98 : 120-134. doi : 10.1080 / 00045600701734356 .
  4. Jump up^ Zimmerer, KS,“Human Geography and the“ New Ecology „: The Prospect of Promise and Integration“,Annals of the Assoc. of American Geo. ,84(1), 108-125, (1994)
  5. Jump up^ „UN World Population Report 2001“ (PDF) . p. 31 . Retrieved 16 December 2008 .
  6. Jump up^ Ryerson, WF (2010), „Population, The Multiplier of Everything Else“, in McKibben, D, The Post Carbon Reader: Managing the 21st Centery Sustainability Crisis , Watershed Media, ISBN  978-0-9709500-6-2
  7. Jump up^ Brown, LR (2011). World on the Edge . Earth Policy Institute. Norton. ISBN  978-0-393-08029-2 .
  8. ^ Jump up to:b Ehrlich, Paul R ; Ehrlich, Anne H (2004), One with Nineveh: Politics, Consumption, and the Human Future , Island Press / Shearwater Books, pp. 137, 182, see also pages 76-236
  9. Jump up^ Cliggett, L., „Carrying Capacity’s New Guise: Folk Models for Public Debate and Longitudinal Study of Environmental Change“, Africa Today,48(1), 2-19, (2001)
  10. Jump up^ Fred Pearce (2009-04-13). „Consumption Dwarfs Population as Main Environmental Threat“ . Yale University . Retrieved 2012-11-12 .
  11. Jump up^ Ehrlich, Paul R ; Ehrlich, Anne H (2008), The Dominant Animal: Human Evolution and the Environment , Island Press / Shearwater Books, pp. 235, see also pages 234-309
  12. Jump up^ Ehrlich, PR, Holdren, JP, „Impact of Population Growth“, Science,171(3977), 1212-1217, (1971)
  13. Jump up^ Swafford, Angela Lynn. „Logistic Population Growth: Equation, Definition & Graph.“ Study.com. Np, 30 May 2015. Web. 21 May 2016. „Logistic Population Growth – Boundless Open Textbook.“ Boundless. Np, nd Web. May 21, 2016.
  14. Jump up^ Martire, S., Castellani, V., & Sala, S. (2015). Carrying capacity assessment of forest resources, Conservation and Recycling, 94, 11-20. doi:[1]
  15. Jump up^ Economy, E.,China vs. Earth, The Nation, May 7, 2007 issue
  16. Jump up^ Nielsen, R.,The Little Green Handbook,Picador, (2006)ISBN 978-0-312-42581-4
  17. Jump up^ Brown, LR (2011). World on the Edge . Earth Policy Institute. Norton. p. 7. ISBN  978-0-393-08029-2 .
  18. ^ Jump up to:b Wackernagel, M .; Schulz, NB; et al. (2002). “ “ Tracking the ecological overshoot of the human economy “ . Proc Natl Acad Sci USA…. . 99 (14): 9266-9271. Bibcode : 2002PNAS … 99.9266W . Doi : 10.1073 / pnas.142033699 . PMC  123129  . PMID  12089326 .
  19. Jump up^ Rees, WE and Wackernagel, M.,Ecological Footprints and Appropriated Carrying Capacity: Measuring the Natural Capital Requirements of the Human Economy, Jansson, A., Folke, C., Hammer, M. and R. Costanza (ed. ),Island Press, (1994)
  20. Jump up^http://www.footprintnetwork.org/en/index.php/GFN/page/frequently_asked_technical_questions/
  21. Jump up^ Holden, Erling; Linnerud, Kristin (May 2007). „The sustainable development area: satisfying basic needs and ecological sustainability“. Sustainable Development . 15 (3): 174-187. doi : 10.1002 / sd.313 .