Summary
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| Figure 1. California Kelp Forest Source: 14 |
Kelp forests are one of the oceans most
diverse ecosystems that’s biodiversity is comparable to a coral reef’s, and
kelp forests are found throughout the world’s oceans although some of the most
diverse kelp forests are located along California’s coast. Kelp forests thrive
along coastlines that have cool nutrient rich currents, and hard rocky sea
floors where their root system known as a holdfast can attach itself. In a similar
structure to tertiary forests kelp forests have a canopy, undergrowth, and floor
where over one thousand species reside; so this biome is very important in maintaining
an overall healthy coastal environment. Some of the California’s most
ecologically diverse kelp forests are found throughout the Central and Southern
coastal regions of the state, but increasingly anthropogenic sources have
resulted in decreases to the overall area of kelp forests along California’s
coast. Within a kelp forests there are various algal species present, but Macrocystis
pyrifera (Giant Kelp) a species of brown algae is the most important because it
provides the forest’s foundation and without it kelp forests wouldn’t be able
to fully develop into the complex biome that they can become (10, 12).
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| Figure 2. Monterey Bay Kelp Forest Source: 15 |
History
California’s
kelp forests also play a very important role in supporting the surrounding
ecosystems too; although historically California’s kelp forests were far more
extensive and the ecosystems were more diverse then their current composition
especially Southern California’s forests. It is being speculated that kelp
forests were what lead people to migrate from Asia over to America, for there
is an almost continuous kelp forest trail between Japan and California (5). Although over the last two Centuries in particular
Southern California’s kelp forests have been decimated by overexploitation,
pollution, and development resulting in some areas losing up to 80 percent of
their historical kelp forests like Orange County. During the early decades of
the 20th Century kelp forests were recorded along both Los Angeles’
and Tijuana’s coast, but pollution and sewage resulted in their disappearance as
early as the 1950’s (2, 6). The leading reason for the decline of Southern
California’s kelp forests are anthropogenically based sources that for centuries
have been reducing suitable areas for Macrocystis pyrifera to colonize and is continuing
to happen today too. One of the most devastating losses to Southern
California’s kelp forests was during the 19th century when the
southern sea otter a keystone species went extinct because they were heavily
overexploited throughout California, and they were even thought to be extinct
throughout the remainder of the 19th century until a single colony
of fifty were found in the 1930’s around Big Sur, California (12, 7).
Anthropogenic Impacts
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| Figure 3. Sea Otter Eating Urchins Source: 16 |
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| Figure 4. Graph Comparing Wave Disturbance to Primary productivity Source: 17 |
One of
the most important species that’s responsible in large part for maintaining a healthy
and balanced kelp forests are sea otters so they are considered a keystone
species, for without them Southern California’s kelp forests began to decline
due to an increase in sea urchins whose preferred food source is Macrocystis
pyrifera and who is primarily preyed upon by sea otters. Regrettably sea otters
were highly prized for their pelts and were hunted to extinction in the 19th century,
but luckily in the 1930’s a colony of around fifty were found around Big Sur
California and today there are over two thousand but none still in Southern
California. The exploitation of sea otters wasn’t the only anthropogenic form
of destruction, for pollution and erosion are responsible for reducing the
range of Macrocystis pyrifera because it needs a rocky substrate in order to
colonize an area not soft, sandy sediments that erosion deposits. The 20th
century brought about drastic increases in urbanization, agriculture, and
immigration resulting in ever increasing amounts of pollution that the state
still struggles to cope with (8, 1). Fishing is a very detrimental practice for
kelp forests especially commercial fishing since typically the fish targeted by
humans are apex predators such as Sheepshead fish and spiny lobsters that play
an important role in regulating the population of grazing fish species to keep
the kelp forests density healthy and balanced (12), but they are also affected
adversely by pollution as well.
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| Figure 5. Effect of Each Environmental Predictor on Kelp Canopy Biomass Source: 18 |
California
is the most populous state in America and most of the population resides within
Southern California, so counties like Los Angeles, Orange, and San Diego have
been seen a decline in kelp forests due to pollution entering the ocean when through
gutters during the rains contaminating the local epipelagic zone (1). Along
California’s coast there is where California had located three nuclear power plants
(Diablo Canyon, Humboldt Bay, and San Onofre), which would intake massive
amounts of sea water containing various aquatic organisms resulting in the drastic
decline of species in local kelp forests but today only Diablo Canyon remains operational.
This year one of the most devastating events to all of California’s kelp
forests is a natural phenomenon that is set to occur this year called El Nino
Southern Oscillation (ENSO) an event that results in increasing precipitation
across the state, but also results in an increasing sea temperature which
results in decreasing kelp forests density and destroying many others.
Macrocystis pyrifera thrives better in cold nutrient rich water so the warm
water hampers the growth of kelp forests and stresses them out. Kelp forests
historically have adapted to the El Nino phenomenon but compounding El Nino
with high amounts of pollution, runoff, and erosion it becomes very challenging
for kelp forests to persists since they already struggling with anthropogenic factors
let alone combining those factors with an increase in storms. Since the 1960’s
and 70’s California has been monitoring their kelp forests and especially since
the beginning of the 21st century various efforts are h to protect
and restore Southern California’s kelps forests (6, 10).
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| Figure 6. Southern California MPA's Source: 19 |
Outlook
Throughout
the region there are both governmental agencies as well as non-profit
organizations who have been working to restore the forests, but this is a
relatively new trend that will have to continue for years to come in order to ensure
their protection for future generations to enjoy. At the local level there are
cities like Laguna Beach, California that have completely outlawed any fishing
off the coast by creating marine-protected areas (MPA) which has far reaching
benefits especially to the surrounding coasts and ecosystems. Throughout Southern
California there are fifty MPA’s that oversee and protect over 350 square miles
of California’s coastal waters, and they are like National forests but for
aquatic environments so that these important resources will be conserved
ensuring future generations will be able to enjoy them too (4). MPA’s benefit
the surrounding waters too because it provides a safe haven from anthropogenic activities
primarily fishing, so many species can recover and since they’re mobile they
swim in and out resulting in an increase in the productivity of fishing the
surrounding unprotected areas. There are costs associated with maintaining MPAs
but the benefits to California’s coastal ecosystems far outweighs the costs
associated with maintenance and enforcement since they ensure that fish stocks
will be preserved and not completely exploited (3). If current efforts are
maintained as well as implementing several additional policies to ensure that
every effort is made to protect these important ecosystems.
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| Figure 7. Benefits of MPA's Source: 20 |
Improvements
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| Figure 8. Before & After Restoration Project Source: 21 |
Overall
the outlook for Southern California’s kelp forests is relatively good because
they are able to colonize and grow quite quickly in comparison to terrestrial
forests, so recovery is very possible if pollution is reduced and water
temperatures remain cool and nutrient rich. There are also numerous non-profit
organizations such as The Bay Foundation, Coastkeepers, and LA Waterkeepers which
are all helping by participating in kelp forest restoration projects throughout
California’s coastal areas helping accelerate the regrowth of many forests (12).
These groups grow kelp themselves and cull sea urchin barrens to ensure the
recovery of these forests is as quick as possible, and the incredibly high
urchin populations results in a lack of available resources leading to a
reduction in their size as well (1). The future looks bright for kelp forests
if these efforts are continued, for MPA’s are very beneficial, but pollution and
runoff continues today throughout Southern California leaving many areas unaddressed
(4). One city that provides an example that could be replicated along the coast
where funding is available is Huntington Beach, for they depend on tourism
during the summer so to combat polluted runoff they began treating the runoff
during the summer months. This program was initiated out of economic reasons to
protect the tourism industry but incidentally it ended up benefiting the local coastal
ecosystems such as kelp forests too, so hopefully in the future programs similar
to this one can be developed that most importantly protect coastal ecosystems
and biome but can also benefit the local economy as well (9). Despite all of
these efforts and legislation to protect these important biomes there is still
a much larger issue that needs to be addressed and that is climate change, for climate
change is the most important issue facing kelp forests over the long-term
because it can result in altered currents, temperatures, and sea levels resulting
in a decrease in the overall range and area of kelp forests.
Work Cited
1. Bell Devereaux. 2014. Why divers are
restoring California’s kelp forests. Mother Nature Network. http://www.mnn.com/earth-matters/wilderness-resources/stories/why-divers-are-restoring-californias-kelp-forests.
Web. 16/11/2015.
2. Bushing, W.
W., 1994. Biogeographic and ecological implications of kelp rafting as a
dispersal vector for marine invertebrates. In Halvorson, W. and G. Maender
(eds.), Proceedings of the Fourth California Islands Symposium: Update on the
Status of Resources, March 22-25, 1994. Santa Barbara Museum of Natural History
(Santa Barbara, CA). pp. 103-110. 12/11/2015.
3. Guidetti P, Baiata P, Ballesteros
E, Di Franco A, Hereu B, Macpherson E, et al. (2014) Large-Scale Assessment of
Mediterranean Marine Protected Areas Effects on Fish Assemblages. PLoS ONE
9(4): e91841. doi:10.1371/journal.pone.0091841. Web. 16/11/2015.
4.California
Department of Fish and Wildlife. 2015. Southern California Marine Protected
Areas. https://www.wildlife.ca.gov/Conservation/Marine/MPAs/Network/Southern-California.
Web. 21/11/2015.
5. Carey, Bjorn. 2006. Ancient People Followed ‘Kelp Highway’ to America, Researcher Says. Live Science.
http://www.livescience.com/7042-ancient-people-kelp-highway-america-researcher.html.
Web. 18/11/2015.
6.
Grove, R. S., Zabloudil, K., Norall, T., and Deysher, L. 2002. Effects of El
Nin ̃o events on natural kelp beds and artificial reefs in southern California.
– ICES Journal of Marine Science, 59: S330–S337. 08/11/2015.
7. Landis, ben Young. 2014. Slowly Swimming Towards
Recovery, California’s Sea Otter Numbers Holding Steady. USGS. http://www.usgs.gov/blogs/features/usgs_top_story/slowly-swimming-towards-recovery-californias-sea-otter-numbers-holding-steady/.
Web. 20/11/2015
8. Limbaugh,
Conrad. (1955). Fish life in the kelp beds and the effects of kelp harvesting. Scripps
Institution of Oceanography. UC San Diego: Scripps Institution of
Oceanography. Retrieved from: http://escholarship.org/uc/item/4w36x6mb.
Web. 18/11/2015
9.
Mehta, Steema. 2000. O.C. Pulls
Out Stops to Keep Beaches Clean. Los Angeles Times. http://articles.latimes.com/2000/may/19/news/mn-31791. Web.
20/11/2015.
10.
Meurant, Gerard. 1987. Advances in Ecological Research. Volume 17. Chapter 5 El Niňo Effects on Southern California Kelp Forest Communities.
Academic Press, pp 243-280. 16/11/2015
11.
National Oceanic and Atmospheric Administration. 2014. What is a kelp forest.
N.O.A.A. http://oceanservice.noaa.gov/facts/kelp.html. Web. 15/11/2015.
12. Steneck Robert S., Graham Michael H.,
Bourque Bruce J., Corbett Debbie, Erlandson Jon M., Estes James A., and Tegner
Mia J. 2002. Kelp forest ecosystems: biodiversity, stability, resilience and future.
Environmental Conservation, pp 436-459. doi:10.1017/S0376892902000322.
12/11/2015.
13. The Bay Foundation. 2014. Kelp Forest
Restoration. Santa Monica Bay Foundation. http://www.santamonicabay.org/learn/our-work/in-the-ocean/kelp-forest-restoration/.
Web. 15/11/2015
14 Figure 1. Kelp Forest Image. http://www.roughguides.com/wp-content/uploads/2014/10/Final-Giant-Kelp-Forests-Monterey-Bay00000-977115-1680x1050.jpg Figure 4. Image of Graph. https://www.lternet.edu/research/keyfindings/wave-impact
15. Figure 2. http://i2.wp.com/goforth-explorer.com/wp-content/uploads/2014/11/Monterey-Bay-Kelp-Forest.jpg?fit=1200%2C1200
16. Figure 3. http://www.esa.org/esa/wp-content/uploads/2014/08/sea-otter-with-urchins.jpg
17. Figure 4. Image of Graph. https://www.lternet.edu/research/keyfindings/wave-impact
18. Figure 5. http://onlinelibrary.wiley.com/store/10.1111/jbi.12550/asset/image_n/jbi12550-fig-0004.png?v=1&t=ihcm6kg0&s=9fbacd55ab70185aeb9842933f7eaedc21d03f3f
19. Figure 6. Map of California's Kelp Forests. https://noottersnokelp.files.wordpress.com/2015/03/cali-map.jpg
20. Figure 7. MPA vs No MPA Image. http://www.oceanconservancy.org/places/pacific-coast/californias-mpas.html
21. Figure 8. http://www.santamonicabay.org/learn/our-work/in-the-ocean/kelp-forest-restoration/
