Editing Ecosystem (section)

=== Dynamics and resilience ===
{{Further|Resistance (ecology)|Ecological resilience}}

Ecosystems are dynamic entities. They are subject to periodic disturbances and are always in the process of recovering from past disturbances.<ref name="Chapin-2011k" />{{rp|347}} When a [[perturbation (biology)|perturbation]] occurs, an ecosystem responds by moving away from its initial state. The tendency of an ecosystem to remain close to its equilibrium state, despite that disturbance, is termed its [[resistance (ecology)|resistance]]. The capacity of a system to absorb disturbance and reorganize while undergoing change so as to retain essentially the same function, structure, identity, and feedbacks is termed its [[ecological resilience]].<ref>{{Cite book|title=Principles of ecosystem stewardship: resilience-based natural resource management in a changing world|date=2009|publisher=Springer|editor-first1=F. Stuart III |editor-last1=Chapin |editor-first2=Gary P. |editor-last2=Kofinas |editor-first3=Carl |editor-last3=Folke |editor-first4=Melissa C. |editor-last4=Chapin|isbn=978-0-387-73033-2|edition=1st|location=New York|oclc=432702920}}</ref><ref>{{Cite journal|last1=Walker|first1=Brian|last2=Holling|first2=C. S.|last3=Carpenter|first3=Stephen R.|last4=Kinzig|first4=Ann P.|date=2004|title=Resilience, Adaptability and Transformability in Social-ecological Systems|url=http://www.ecologyandsociety.org/vol9/iss2/art5/|journal=Ecology and Society|language=en|volume=9|issue=2|pages=art5|doi=10.5751/ES-00650-090205 |doi-access=free |issn=1708-3087|hdl=10535/3282|hdl-access=free|access-date=2021-07-23|archive-date=2019-05-17|archive-url=https://web.archive.org/web/20190517073955/https://www.ecologyandsociety.org/vol9/iss2/art5/|url-status=live}}</ref> Resilience thinking also includes humanity as an integral part of the [[biosphere]] where we are dependent on [[ecosystem services]] for our survival and must build and maintain their natural capacities to withstand shocks and disturbances.<ref>{{Cite web|last=Simonsen|first=S.H. |publisher=Stockholm Resilience Centre |title=Applying Resilience Thinking|url=https://whatisresilience.org/wp-content/uploads/2016/04/Applying_resilience_thinking.pdf|url-status=live|archive-url=https://web.archive.org/web/20171215163627/http://whatisresilience.org:80/wp-content/uploads/2016/04/Applying_resilience_thinking.pdf |archive-date=2017-12-15 }}</ref> Time plays a central role over a wide range, for example, in the slow development of soil from bare rock and the faster [[ecological succession|recovery of a community from disturbance]].<ref name="Chapin-2011e" />{{rp|67}}

[[Disturbance (ecology)|Disturbance]] also plays an important role in ecological processes. [[F. Stuart Chapin III|F. Stuart Chapin]] and coauthors define disturbance as "a relatively discrete event in time that removes plant biomass".<ref name="Chapin-2011k">{{Cite book|last=Chapin|first=F. Stuart III|title=Principles of terrestrial ecosystem ecology|date=2011|publisher=Springer|others=P. A. Matson, Peter Morrison Vitousek, Melissa C. Chapin|isbn=978-1-4419-9504-9|edition=2nd|location=New York|chapter=Chapter 12: Temporal Dynamics|oclc=755081405}}</ref>{{rp|346}} This can range from [[herbivore]] outbreaks, treefalls, fires, hurricanes, floods, [[Glacial motion|glacial advances]], to [[Types of volcanic eruptions|volcanic eruptions]]. Such disturbances can cause large changes in plant, animal and microbe populations, as well as soil organic matter content. Disturbance is followed by succession, a "directional change in ecosystem structure and functioning resulting from biotically driven changes in resource supply."<ref name="Chapin-2011m">{{Cite book|last=Chapin|first=F. Stuart III|title=Principles of terrestrial ecosystem ecology|date=2011|publisher=Springer|others=P. A. Matson, Peter Morrison Vitousek, Melissa C. Chapin|isbn=978-1-4419-9504-9|edition=2nd|location=New York|chapter=Glossary|oclc=755081405}}</ref>{{rp|470}}

The frequency and severity of disturbance determine the way it affects ecosystem function. A major disturbance like a volcanic eruption or [[Glacier|glacial]] advance and retreat leave behind soils that lack plants, animals or organic matter. Ecosystems that experience such disturbances undergo [[primary succession]]. A less severe disturbance like forest fires, hurricanes or cultivation result in [[secondary succession]] and a faster recovery.<ref name="Chapin-2011k" />{{rp|348}} More severe and more frequent disturbance result in longer recovery times.

From one year to another, ecosystems experience variation in their biotic and abiotic environments. A [[drought]], a colder than usual winter, and a pest outbreak all are short-term variability in environmental conditions. Animal populations vary from year to year, building up during resource-rich periods and crashing as they overshoot their food supply. Longer-term changes also shape ecosystem processes. For example, the forests of eastern North America still show legacies of [[Agriculture|cultivation]] which ceased in 1850 when large areas were reverted to forests.<ref name="Chapin-2011k" />{{rp|340}} Another example is the [[methane]] production in eastern [[Siberia]]n lakes that is controlled by [[organic matter]] which accumulated during the [[Pleistocene]].<ref>{{Cite journal|last1=Walter|first1=K. M.|last2=Zimov|first2=S. A.|last3=Chanton|first3=J. P.|last4=Verbyla|first4=D.|last5=Chapin|first5=F. S.|date=2006|title=Methane bubbling from Siberian thaw lakes as a positive feedback to climate warming|url=http://faculty.jsd.claremont.edu/emorhardt/159/pdfs/2007/Walter%20et%20al.%202006.pdf |journal=Nature|language=en|volume=443|issue=7107|pages=71–75|doi=10.1038/nature05040|pmid=16957728|bibcode=2006Natur.443...71W|s2cid=4415304 |s2cid-access=free |issn=0028-0836|access-date=2021-08-16|archive-date=Nov 23, 2011 |archive-url=https://web.archive.org/web/20111123193233/http://faculty.jsd.claremont.edu/emorhardt/159/pdfs/2007/Walter%20et%20al.%202006.pdf |url-status=dead }}</ref>

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[[File:Panorama presa las niñas mogan gran canaria.jpg|thumb|upright=4.1|center|{{center|1=A [[freshwater]] lake in [[Gran Canaria]], an [[island]] of the [[Canary Islands]]. Clear boundaries make lakes convenient to study using an [[ecosystem approach]].}}]]