Editing Kelp forest (section)

== Patch dynamics ==
Another major area of kelp forest research has been directed at understanding the spatial-temporal patterns of kelp patches. Not only do such dynamics affect the physical landscape, but they also affect species that associate with kelp for refuge or foraging activities.<ref name="Foster 1985" /><ref name="Carr" /> Large-scale environmental disturbances have offered important insights concerning mechanisms and ecosystem [[Resilience (ecology)|resilience]]. Examples of environmental disturbances include:
*Acute and chronic [[pollution]] events have been shown to impact southern California kelp forests, though the intensity of the impact seems to depend on both the nature of the contaminants and duration of exposure.<ref>Grigg, R.W. and R.S. Kiwala. 1970. Some ecological effects of discharged wastes on marine life. California Department of Fish and Game 56: 145–155.</ref><ref>{{Cite report |chapter-url=https://ieeexplore.ieee.org/document/586780 |chapter=Contaminants In Sediments Near A Major Marine Outfall: History, Effects, And Future |last=Stull |first=J.K. |title=Proceedings OCEANS |date=1989 |publisher=IEEE |doi=10.1109/OCEANS.1989.586780 |volume=2 |pages=481–484 |access-date=2024-10-06 |archive-date=2024-07-10 |archive-url=https://web.archive.org/web/20240710080759/https://ieeexplore.ieee.org/document/586780/ |url-status=live }}</ref><ref>{{Cite journal |last1=North |first1=W. J. |last2=James |first2=D. E. |last3=Jones |first3=L. G. |date=June 1993 |title=History of kelp beds (Macrocystis) in Orange and San Diego Counties, California |url=http://link.springer.com/10.1007/BF00049029 |journal=Hydrobiologia |language=en |volume=260-261 |issue=1 |pages=277–283 |doi=10.1007/BF00049029 |bibcode=1993HyBio.260..277N |issn=0018-8158 |access-date=2024-10-06 |archive-date=2024-10-07 |archive-url=https://web.archive.org/web/20241007152854/https://link.springer.com/article/10.1007/BF00049029 |url-status=live |url-access=subscription }}</ref><ref>{{Cite journal |last1=Tegner |first1=M.J. |last2=Dayton |first2=P.K. |last3=Edwards |first3=P.B. |last4=Riser |first4=K.L. |last5=Chadwick |first5=D.B. |last6=Dean |first6=T.A. |last7=Deysher |first7=L. |date=January 1995 |title=Effects of a large sewage spill on a kelp forest community: Catastrophe or disturbance? |url=https://linkinghub.elsevier.com/retrieve/pii/014111369400008D |journal=Marine Environmental Research |language=en |volume=40 |issue=2 |pages=181–224 |doi=10.1016/0141-1136(94)00008-D |bibcode=1995MarER..40..181T |access-date=2024-10-06 |archive-date=2024-07-11 |archive-url=https://web.archive.org/web/20240711050052/https://linkinghub.elsevier.com/retrieve/pii/014111369400008D |url-status=live |url-access=subscription }}</ref><ref>{{Cite journal |last1=Carpenter |first1=S. R. |last2=Caraco |first2=N. F. |last3=Correll |first3=D. L. |last4=Howarth |first4=R. W. |last5=Sharpley |first5=A. N. |last6=Smith |first6=V. H. |date=August 1998 |title=Nonpoint Pollution of Surface Waters with Phosphorus and Nitrogen |url=http://doi.wiley.com/10.1890/1051-0761(1998)008[0559:NPOSWW]2.0.CO;2 |journal=Ecological Applications |language=en |volume=8 |issue=3 |pages=559–568 |doi=10.1890/1051-0761(1998)008[0559:NPOSWW]2.0.CO;2 |hdl=1808/16724 |issn=1051-0761|hdl-access=free }}</ref> Pollution can include sediment deposition and [[eutrophication]] from sewage, industrial byproducts and contaminants like [[PCBs]] and heavy metals (for example, copper, zinc), runoff of [[organophosphates]] from agricultural areas, anti-fouling chemicals used in harbors and marinas (for example, [[Tributyltin|TBT]] and [[creosote]]) and land-based pathogens like [[fecal coliform bacteria]].
*Catastrophic storms can remove surface kelp canopies through wave activity, but usually leave understory kelps intact; they can also remove urchins when little spatial refuge is available.<ref name="Dayton1992" /><ref name="Ebeling" /> Interspersed canopy clearings create a seascape mosaic where sunlight penetrates deeper into the kelp forest and species that are normally light-limited in the understory can flourish. Similarly, substrate cleared of kelp holdfasts can provide space for other sessile species to establish themselves and occupy the seafloor, sometimes directly competing with juvenile kelp and even inhibiting their settlement.<ref>{{Cite journal |last=Kennelly |first=Steven J. |date=1987 |title=Physical disturbances in an Australian kelp community. I. Temporal effects |url=https://www.jstor.org/stable/24825709 |journal=Marine Ecology Progress Series |volume=40 |issue=1/2 |pages=145–153 |doi=10.3354/meps040145 |jstor=24825709 |bibcode=1987MEPS...40..145K |issn=0171-8630|url-access=subscription }}</ref>
* [[El Niño-Southern Oscillation]] (ENSO) events involve the depression of oceanographic thermoclines, severe reductions of nutrient input, and changes in storm patterns.<ref name="Dayton1992" /><ref>{{Cite journal |last=McPhaden |first=M. J. |date=1999-02-12 |title=Genesis and evolution of the 1997-98 El Nino |url=https://pubmed.ncbi.nlm.nih.gov/9974381/ |journal=Science |volume=283 |issue=5404 |pages=950–954 |doi=10.1126/science.283.5404.950 |issn=1095-9203 |pmid=9974381 |access-date=2024-10-06 |archive-date=2024-06-25 |archive-url=https://web.archive.org/web/20240625075738/https://pubmed.ncbi.nlm.nih.gov/9974381/ |url-status=live }}</ref> Stress due to warm water and [[nutrient depletion]] can increase the susceptibility of kelp to storm damage and herbivorous grazing, sometimes even prompting phase shifts to urchin-dominated landscapes.<ref name="Vasquez" /><ref name="Dayton 1984" /><ref>{{Cite journal |last1=Edwards |first1=M. S. |last2=Hernández-Carmona |first2=G. |date=May 2005 |title=Delayed recovery of giant kelp near its southern range limit in the North Pacific following El Niño |url=http://link.springer.com/10.1007/s00227-004-1548-7 |journal=Marine Biology |language=en |volume=147 |issue=1 |pages=273–279 |doi=10.1007/s00227-004-1548-7 |bibcode=2005MarBi.147..273E |issn=0025-3162 |access-date=2024-10-06 |archive-date=2024-10-07 |archive-url=https://web.archive.org/web/20241007175425/https://link.springer.com/article/10.1007/s00227-004-1548-7 |url-status=live |url-access=subscription }}</ref> In general, oceanographic conditions (that is, water temperature, currents) influence the recruitment success of kelp and its competitors, which clearly affect subsequent species interactions and kelp forest dynamics.<ref name="Dayton1992" /><ref>{{Cite journal |last1=Duggins |first1=David O. |last2=Eckman |first2=James E. |last3=Sewell |first3=Amy T. |date=October 1990 |title=Ecology of understory kelp environments. II. Effects of kelps on recruitment of benthic invertebrates |url=https://linkinghub.elsevier.com/retrieve/pii/002209819090109P |journal=Journal of Experimental Marine Biology and Ecology |language=en |volume=143 |issue=1–2 |pages=27–45 |doi=10.1016/0022-0981(90)90109-P |bibcode=1990JEMBE.143...27D |access-date=2024-10-06 |archive-date=2024-10-07 |archive-url=https://web.archive.org/web/20241007153235/https://www.sciencedirect.com/unsupported_browser |url-status=live |url-access=subscription }}</ref>
*Overfishing higher trophic levels that naturally regulate herbivore populations is also recognized as an important stressor in kelp forests.<ref name="Sala1998" /><ref name="Halpern2006" /><ref name="Jackson2001">{{Cite journal |last1=Jackson |first1=Jeremy B. C. |last2=Kirby |first2=Michael X. |last3=Berger |first3=Wolfgang H. |last4=Bjorndal |first4=Karen A. |last5=Botsford |first5=Louis W. |last6=Bourque |first6=Bruce J. |last7=Bradbury |first7=Roger H. |last8=Cooke |first8=Richard |last9=Erlandson |first9=Jon |last10=Estes |first10=James A. |last11=Hughes |first11=Terence P. |last12=Kidwell |first12=Susan |last13=Lange |first13=Carina B. |last14=Lenihan |first14=Hunter S. |last15=Pandolfi |first15=John M. |date=2001-07-27 |title=Historical Overfishing and the Recent Collapse of Coastal Ecosystems |url=https://www.science.org/doi/10.1126/science.1059199 |journal=Science |language=en |volume=293 |issue=5530 |pages=629–637 |doi=10.1126/science.1059199 |pmid=11474098 |issn=0036-8075 |access-date=2024-10-06 |archive-date=2024-10-07 |archive-url=https://web.archive.org/web/20241007152403/https://www.science.org/doi/10.1126/science.1059199 |url-status=live |url-access=subscription }}</ref> As described in the previous section, the drivers and outcomes of trophic cascades are important for understanding spatial-temporal patterns of kelp forests.<ref name="Estes1995" /><ref name="Pearse&Hines" /><ref name="Sala&Graham" />

In addition to ecological monitoring of kelp forests before, during, and after such disturbances, scientists try to tease apart the intricacies of kelp forest dynamics using experimental manipulations. By working on smaller spatial-temporal scales, they can control for the presence or absence of specific biotic and abiotic factors to discover the operative mechanisms. For example, in southern Australia, manipulations of kelp canopy types demonstrated that the relative amount of ''Ecklonia radiata'' in a canopy could be used to predict understory species assemblages; consequently, the proportion of ''E. radiata'' can be used as an indicator of other species occurring in the environment.<ref>{{Cite journal |last1=Irving |first1=Andrew D. |last2=Connell |first2=Sean D. |date=June 2006 |title=Predicting understorey structure from the presence and composition of canopies: an assembly rule for marine algae |url=https://link.springer.com/article/10.1007/s00442-006-0389-0 |journal=Oecologia |language=en |volume=148 |issue=3 |pages=491–502 |doi=10.1007/s00442-006-0389-0 |pmid=16502000 |bibcode=2006Oecol.148..491I |issn=0029-8549 |access-date=2024-10-06 |archive-date=2022-01-20 |archive-url=https://web.archive.org/web/20220120064715/https://link.springer.com/article/10.1007%2Fs00442-006-0389-0 |url-status=live |url-access=subscription }}</ref>