Sunday, April 29, 2012

Not So Pesky Ants: Their Role in Ecosystem Services


When I think of ants, my automatic reaction is annoyance.  I envision the common scenario in many college student homes: you left that half-finished bowl of Cookie Crisp out one day too long, or did not wipe up that juice you spilled on the counter while using it for a chaser in a timely fashion. Before long, you have tiny invaders all over your kitchen, and their numbers seem endless.  Although these ants are a frequent source of frustration for many of us, it is time we gave ants some credit for actually helping us out instead of blaming them for attacking our forgotten sandwich crusts.

We as humans benefit directly from many processes in nature in a variety of ways. This concept has been dubbed ‘ecosystem services’,  and can cover a range of activities from  carbon sequestration to pharmaceutical production to ecotourism.  Ecosystem services have been divided into four main categories: provisioning, supporting, regulating, and cultural.  These services have a direct effect on human well-being, allowing us to live somewhat spoiled lives because nature takes care of so many things for us automatically and without a monetary cost.
 Imagine if we had to pay bacteria for nutrient cycling? Ecosystem services are essential to our lives as we know it, and yet many go unnoticed and unappreciated by the majority of the planet’s human population. Well, it is time for ants to go unappreciated no longer. They provide the human species with a service in each of the four categories of ecological services, and deserve some positive attention for once. Ants aren't often credited with playing a role in maintaining our well-being, but I will show you how they contribute in every single aspect of the intertwined chart between nature and humans shown above.

One of the most important services provided by ants is their role in agriculture. This falls in the category of a supporting service. In 2011, Evans et al provided 
a research article that credited ants (as well as termites) with increasing wheat crop yields by 36% in dry, arid climates. This is an important service for farmers because it is a way to be more efficient without investing more money. It also allows crops to grow in areas where they can just as easily fail. The ‘green revolution’ is the term coined for the intensification of agricultural productivity in the last century. We can see that crop yields have definitely increased, but often those results are due to herbicides and other potentially harmful agents, or the use of excessive amounts of water. Ants however, allow for the crop yield to rise in a sustainable way – which is good for everyone involved. It provides a service to humans, while also helping to maintain biodiversity in these agricultural areas that normally are detrimental to biodiversity levels. Ants accomplish this amazing feat by just doing what they normally do, building tunnels in the ground. As the ants build their colonies under these dry, arid grounds, they allow for increased water infiltration and increase the amount of nitrogen in the soil. These factors allow the wheat more of the sustenance it needs to grow, and for free!And if contributing to the growth of wheat just isn’t enough, ants have also been shown to be key in agroecosystems that specialize in the production of coffee, chocolate, and wine (Chong et al 2011 and Philpott et al 2006). As it happens, those are three of my absolute favorite things in the world, so I have to give props to ants for acting as predators in these agroecosystems and protecting these much loved products from disease so they can be available for my consumption. The ants present in these ecosystems act as biological control agents, protecting the plants from insect pests and fungal pathogens, which allows for increased plant growth and reproduction. Thank you, ants.

Honey Ants eaten in Central OZ
An unexpected area of contribution that ants play a role in is the ‘provisioning’ category of ecosystem services. It may surprise you that according to Neelkamal Rastogi, ants are an “unconventional human food source” (2011). In some areas of Southeast Asia, China, South and Central America, Africa, and Australia, ants are a significant source of protein for many indigenous people. There are several species that are edible in both the adult and larvae stage of life, and in some tribes ants are prepared in such a way that they are considered a delicacy. My personal favorite method of ant consumption is mashing them up and mixing them into water to make a “pleasant sour drink”, as is done by Queensland, Australia natives (Rastogi 2011). Mmmmm…protein.

Another important ecosystem service provided by ants is in the regulation category. One might not often think of ants right off the bat when ‘disease prevention’ is mentioned, but those pesky little buggers have some tricks up their sleeve.  Like using ants as a source of nutritional protein, many native peoples across the world also traditionally used ants to treat a wide variety of diseases and afflictions.  In Africa, the mandibles of some ants were used as sutures. In India, another species was ground up and used to treat gout and joint pain. Yes, these are not the methods we use in Western medicine, but ants have also become an important source for pharmaceuticals, namely antibiotics because of their well-developed immune systems and ability to resist disease (Rastogi 2011). Pharmacological companies are continuing to investigate ants as a source of treatment to diseases such as arthritis and asthma. One more ecological service, brought to you courtesy of ants.

 
Ants are Awesome



And last but certainly not least, ants provide us with ecosystem services in the cultural category. Nature has many ways of contributing to our cultural growth and sustenance as humans, ranging from spiritual to aesthetic methods of service. I know some of you may feel that ants often provide a recreational disservice by invading your picnics, but let’s not forget that they contribute to the most essential human cultural service: education. Who doesn’t love watching Planet Earth, getting sucked in to the amazing footage of polar bear cubs and tiny baby sea horses. Well, ants can be pretty amazing too, and if (like me) you love dropping random facts you learn from nerdy TV shows on your friends, then this BBC video on army ants will provide a great cultural ecosystem service to you.  Enjoy.

Citations:
Chong, C., L. Thompson, A. Hoffman. (2011) High diversity of ants in australian vineyards. Australian                       Journal of Entomolgy 50(1): 7-21.
Evans, T., T. Dawes, P. Ward, N. Lo. (2011) Ants and termites increase crop yield in a dry climate. Nature                 Communications 2: 262.
Philpott, S., Armbrecht, I. (2006) Biodiversity in tropical agroforests and the ecological role of ants and                   ant diversity in predatory function. Ecological Entomology 31(4): 369-377.
Rastogi, N. (2011) Provisioning services from ants: food and pharmaceuticals. Asian Myrmecology 4:                       103-120.
Sanford, M., P. Manley, D. Murphy. (2009) Effects on urban development on ant communities:                 implications for ecosystem services and management. Conservation Biology 23(1):  131- 141.

The Demise of Conventional Agriculture 

Hopefully most people around the world have heard of climate change, one of the most challenging issues we are facing today. We also have heard of the issues contributing to climate change: we have too many people on earth, there are too many urban areas, there is too much pollution, and we are losing too much biodiversity. What each of these issues have in common is their relation to the globalized agriculture industry. Agriculture takes up 40% of the earth's land surface which is 60% larger than areas commonly complained about: urban sprawl. What many people don't know is the extent of the impact that our global agriculture industry has on the earth and its organisms, including us. The largest cause of habitat loss around the world is from clearing habitat for the purpose of cultivating crops or farming animals. This habitat loss due to the agriculture industry creates the largest impact on biodiversity worldwide.

Here is an image from 2006 showing the distribution of land used for agriculture around the world (Ahlenius, 2006). The different colors show the ratio of cropland versus grazing land. We can see just about every habitable place on earth is used for agricultural purposes, where most of the remaining areas are barren, deserts, ice, or mountains. Since this image was published, many of the few biodiverse hotspots that were once intact have been exploitated for agriculture use or oil exploration.



The agriculture industry does more than take up space.  Out of the total amount of water used by humans, the agriculture industry uses about 70%. Impacts of this water use are observed widely around the world. For example today, the Colorado River in the western United States no longer reaches the sea due to the intensive withdrawal used for agriculture and drinking water. The Aral Sea is also almost completely dried up as a result of the diversion of its incoming rivers for irrigation.

The impacts of the agriculture industry reach farther than the earth's land and water, but also into our atmosphere. The largest human contribution to global climate change is directly from the agriculture industry, totaling to about 30% of the total greenhouse gas emissions caused by humans. The largest contributors to this impact from agriculture are methane emissions from cows and rice, carbon dioxide emissions from burning tropical rainforests for clearing, nitrous oxide from too many fertilizers, and we have doubled the flows of nitrogen and phosphorous due to the use of fertilizers. The increase in these flows creates many negative impacts including eutrophication of water bodies and water pollution. Jonathan Foley, professor and director of the Institute on the Environment at the University of Minnesota, calls this impact of the agriculture industry, "The Other Inconvenient Truth" in a lecture of his, given in 2010 (Foley, 2010).




Looking at all of these negative impacts may be depressing and infuriating, but we all know that this is the very industry that keeps most of the seven billion people on earth alive and (somewhat) healthy. So what can we do to reduce the impacts of one of the most problematic and prevalent industries in the world? We can model it after Mother Nature herself. Natural ecosystems have unreal amounts of interacting organisms and processes that keep the ecosystems in balance and healthy.  But  humans have tended to mess that balance up. Using methods like permaculture, intercropping, biopesticides, natural predators, and agroforestry, we can improve our methods of producing food to work with the ecosystem and not against it. Creating an ecosystem in these ways allows humans to benefit from the natural ecosystem services provided in a habitat.
 

Some of the relevant ecosystem services in agroecosystems include:
  • Biological pest control: Non-crop environments provide habitat and numerous food sources for natural insect and parasite predators, like insectivorous birds and bats. These organisms provide an ecosystem service to the agroecosytem by naturally controlling pests.
  • Pollination: 35-40% of the total volume of food produced by crops rely on animal pollination. Insects and animals provide the ecosystem service of pollination in agricultural settings as well as almost all other places on earth.
  • Water quantity and quality: Vegetation in natural ecosystems regulates capture, infiltration, retention, and flow of water, throughout the habitat. Soil and plants act as a filter for the incoming water, purifying it naturally, providing an essential ecosystem service. The plants' roots keep hold of the soil, reducing erosion. Plant cover also largely regulates many other aspects of the soil including water retention.
  • Soil structure and fertility: Aeration and abundance of organic matter in soils are essential to nutrient uptake by crops. The presence of plant cover produces litter for decomposition and nutrients, and the movement of invertebrates through the soil creates aeration. Many micro and macro organisms in the soil, such as earthworms and bacteria, regulate the decomposition and availability of nutrients to crops, also providing a fundamental ecosystem service. (Power, 2010).
 An optimal system in agriculture allows for each of these ecosystem services to interact and naturally regulate possible negative processes, provide goods, support beneficial processes, and with a more natural feel to the habitat, there is an appeal to the human senses that gives cultural benefits (Fiedler et al., 2008).

Micheal Pollan describes the agroecosystem of a farmer in Virginia, who uses these interactions on his farm. The farm incorporates ecosystem services that are present in natural ecosystems. One of the aspects of his permaculture farming occurs between the cows, chicken, and the grass (and many other small critters). 

First, the farmer grazes the cattle on a fenced off quarter acre. The farmer then waits three days, and then brings in hens to the previously grazed area. The chicken immediately beelines for the cow patties in search for the larva of flies that have made homes in the dung. The farmer waits three days because on the fourth or fifth day the larva will hatch and produce many flies. So at the time the chickens are released into the pen, the larva are nice and fat and juicy for them to eat. While the chicken are stuffing their mouths they are breaking up and spreading the cow feces while also adding some of their own feces, which is rich in nitrogen. The mixture of feces becomes fertilizer for the grass and in about three weeks the grass is thriving and growing tall. At this point the farmer can come in and cut the grass to sell as hay. About 4-5 weeks later the farmer can use this same plot again, but he can move to a different quarter acre in the mean time, and even use a different species such as sheep. 

From this farm there are many foods produced such as beef, pork, eggs, chicken meat, turkey, rabbit, and other products like grass, hay, and more importantly new soil. The new soil is produced from the critters that decompose some of the grass' roots that are lost after cutting the grass. This loss of roots is due to the grass' need to maintain a certain root/shoot ratio (Pollan, 2007).


The last 7 minutes of this video describes the workings of this aspect of the farm in Virginia. The first ten minutes are interesting as well as Pollan describes an interesting perspective of the interactions between human and non-human organisms.


This is one example of how an agroecosytem thrives when the organisms are free to do what they naturally want to do, working together in symbiotic relationships. These techniques of farming are important for the reduction of the negative impacts of the agricultural industry and, if supported, will hopefully lead to the demise of conventional agriculture.

References:
 Fiedler, Anna K., Doug A. Landis, and Steve D. Wratten. "Maximizing Ecosystem Services from  Conservation Biological Control: The Role of Habitat Management." Biological Control 45 (2008): 254-71. Science Direct. Elsevier, 11 Jan. 2008. Web. 26 Apr. 2012.

Foley, Jonathan. "The Other Inconvenient Truth." TEDx. Oct. 2010. Speech.

 Pollan, Micheal. "The Omnivore's Next Dilema." Monterey, CA. Mar. 2007. Speech.

Power, Alison G. "Ecosystem Services and Agriculture: Tradeoffs and Synergies." Phil. Trans. R. Soc. B 365 (2010): 2959-971. Royal Society Pulishing. The Royal Society, 2010. Web. 26 Apr. 2012.

Images: (in order of appearance)
 Ahlenius, Hugo, and UNEP/GRID-Arendal. "Agriculture Land Use Distribution - Croplands and Pasture Land." Map. Global Environment Outlook 4 (GEO-4). UNEP GRID-Arendal, 2006. Web. 26 Apr. 2012.

USGS. The Vanishing Aral Sea. 2009. Photograph. Land Satellite, Kazakhstan and Uzbekistan. Landsat Update 2009. USGS, 2009. Web. 26 Apr. 2012.

Cicadas. FRESH FOOD. Photograph. Flickr. Mother Nature Network. MNN Holdings. Web. 26 Apr. 2012.



Tuesday, April 24, 2012

This could Bee a problem...


advocacy.britannica.com
2012 Lamborghini Aventador: insideline.com
 In an overpopulated world of close to 7 billion people, we consume much more than would naturally be produced on earth without the help of pollinators as an ecosystem service. A necessity for the abundant amount of food produced can be attributed to the honeybee alone. In the past few decades, honeybees have been the victims of a tragic population decrease. The survival of flowering plants, which includes most fruits, vegetables and nuts, has been dependent on honeybees as their main source of pollination for the past 100 million years, nature’s oldest mutualistic relationship. Honeybees pollinate 1/3 of everything we eat in America valued at 15 billion dollars every year in the U.S. food industry. That is enough money to buy every student at the University of Oregon, 2 brand new 2012 Lamborghinis. 

Without them, our staple foods would greatly consist of rice, wheat and corn. For a balanced and healthy diet, fruits, vegetables and nuts are essential. 60%-80% of wild plants require animal pollinators, whereas 35% of crops are dependant on animal pollinators, a large portion of our diet. In Europe, crops requiring animal pollination account for over 84%.

 For this reason, they are still the most important commercial pollinator worldwide and our diet would suffer dramatically with them out of the picture. The drastic number of bees disappearing in the past few decades has been given the name Colony Collapse Disorder (CCD). Since the honeybees have such a huge impact on our daily lives, it is important to figure out what is causing the crisis around the world to one of the most highly organized and complex societies in the animal kingdom and find a way to reverse or stop the affects. While CCD is thought by many to be a direct result of a single parasite migrating from colony to colony, others believe CCD is a result of a variety of problems in the honeybee colonies creating what is called a “perfect storm” between toxic pesticides, parasites, mal nutrition and possibly an AIDs like virus or any combination thereof.

800,000 of the 2.6 million honeybee colonies have disappeared in the U.S. In some countries, 80% of honeybees have vanished in a 6-month time frame whereas the U.S. has lost 1/3 hives of all honeybees. A few hypotheses for this epidemic is toxic pesticides, parasites, mal nutrition and an AIDs-like virus, though no common environmental agents or chemicals have been isolated relating the affected colonies. The spreading disease, first identified in mid-November, 2006, is only affecting the adult population; adult honeybees are declining while a healthy brood population remains.

Schweiger et al. (2010) suggests that climate change is having a negative effect on the plant-pollinator relationship with warming weather. This shift into warmer temperatures may cause the plants and honeybees to un-synchronize and become vulnerable. Bees rely on flowers, and flowers on bees, if one of these two items adapts to change leaving the other behind, both parties suffer. It is hypothesized that the warming climate is causing shifts in when flowers bloom, thus changing the pollen intake of honeybees and in turn altering their breeding patterns. It may also have an affect of flight times may initiate earlier or last longer. This change in temperature may also alter distribution and range of plants, possibly further away from honeybee hives. All of theses reasons are likely scenarios, but near impossible to test because of all the factors involved.

While most research points to IAPV (Israeli Acute Paralysis Virus) as the most likely cause of CCD, US Department of Agriculture’s researcher Jeffery Pettis has found numerous colonies of healthy bees with reported IAPV infection contributing to the CCD debate for the cause of CCD.

Currently, the most accepted reason for CCD is a combination of factors. Pesticides are being used at startling amounts, parasites are always co-evolving with honeybees creating an arms race, and mal nutrition is evident in the majority of hives. A queen bee, a slave to her job trying to keep up the decreasing number of adults, lays close to 2,500 eggs a day, about 2 million a lifetime. An average honeybee can become a forager after only 3 weeks to account for their short lifespan. Out of a typical 30,000-bee hive, about 100 are male and in the summer, workers live about 30 days.

This mystery of CCD is not only important to both the human race and the survival of ecosystems and food webs throughout the entire world, but also in an economic standpoint. This is because currently, there is no artificial substitution for pollinators. A hive of bees can pollinate 3 million flowers every day whereas a human can hand pollinate less than 30 small trees in a 24-hour period. An example of the role honeybees play in pollination can be found in many parts of China, where in the 1980’s, the excessive use of pesticides wiped out all bees in many areas of China forcing villagers to pollinate their fruits by hand as a substitute to the absent bees. They have to hand collect pollen from the flowers, let it dry and germinate for two days, and then hand pollinate the plants using a stick of bamboo and chicken feathers lightly brushing pollen on every flower individually. If the United States were to lose all honeybee sources, it would cost $90 billion every year to replace bees with humans and pollinate by hand.

Pollinating trees manually in China due to lack of bees
Provided by guardian.co.uk

The U.S. is losing millions of dollars a year to corporations around the world for the rental of bees, mainly Australia. A handful of commercial beekeepers in the U.S. rent out their bees for pollination purposes such as David Hackenberg, a beekeeper who sends pods of honeybees across the country from Maine to California to pollinate almonds and blueberries, but in many cases, the U.S. resorts to renting freights of bees from Australia to keep their agriculture farms producing a healthy, profitable amount of product. A single pod, or hive, of bees is generally rented for pollination at $90 per day with increasing prices each year on account of higher demand. In the United States, beekeepers are facing bankruptcy from vanishing bees, and farms are not producing food.

What can we do to slow down the staggering disappearance of honey bees? At this point, no conclusive evidence has been found for Colony Collapse Disorder, but attempts in cracking this riddle are far from forgotten with teams of scientists working out solutions all over the world. This problem is not endemic to one specific location, but essential worldwide and can cause a crisis greater and more immediate that global warming if a solution is not found soon. Every effort to isolate the problem and implement recovery programs in favor of the honey bee is crucial for ecosystems and nutritional needs everywhere as well as a stable economy.

For more information about the ecosystem services provided by honey bees and for a more in depth look into the problems facing honey bee decline, I recommend watching the movie "Vanishing of the Bees" (available to Netflix subscribers). I have provided the trail for a quick summary.







References

Gallai N., J. Salles, J. Settele, B.E. Vaissière. (2008). Economic Valuation of the Vulnerability of World Agriculture Confronted with Pollinator Decline. Ecological Economics, 68:810-821.

Genersch, E. (2010). Honey bee pathology: current threats to honey bees and beekeeping. Applied Microbiology Biotechnol, 87:87-97.


Kearns C.A., D.W. Inouye, N.M. Waser. (1998). Endangered Mutualisms: The Conservation of Plant-Pollinator Interactions. Annual Reviews Ecology, 29: 83-112.

Potts S.G., J.C. Biesmeijer, C. Kremen , P. Neumann, O. Schweiger, W.E. Kunin. (2010). Global Pollinator Declines: Trends, Impacts and Drivers. Trends in Ecology and Evolution, 25(6).

Schweiger O, J.C. Biesmeijer, R. Bommarco, T. Hickler, P.E. Hume, S. Klotz, I. Kühn, M. Moora, A. Nielsen, R. Ohlemüller, T. Petanidou, S.G. Potts, P. Pysek, J.C. Stout, M.T. Sykes, T. Tscheulin, M. Vilà, G.R. Walther, C. Westphal, M. Winter, M. Zobel and J. Settele. (2010). Multiple Stressors on Biotic Interaction: How Climate Change and Alien Species Interact to Affect Pollination. Biological Reviews, 85: 777-795.

VanEngelsdorp D., J.D. Evans, C. Saegerman, C. Mullin, E. Haubruge, B.K. Nguyen, M. Frazier, D. Cox-Foster, Y. Chen, R. Underwood, D.R. Tarpy and J.S. Pettis.(2009) Colony Collapse Disorder:  A Descriptive Study. PLoS One, 4(8): e6481.

Watanabe, M. (2008). Colony Collapse Disorder: Many Suspects, No Smoking Gun. BioScience, 58(5).







The Cryosphere: The Earth's Frozen Realms



What is the cryosphere? The cryosphere is any part of the Earth that consists of frozen water. This includes snow, ice caps, glaciers, sea ice, and permafrost. Without your knowledge these things have been working hard to provide ecosystem services such as water storage and increasing the Earth's albedo, or the reflectivity of the Earth. But we have also taken a toll on how well these ecosystem services function. This is a cause for concern because a world with a damaged cryosphere means a world with much more water and a lot higher temperatures.

How is this happening and what can we do to stop it?

The issue is global climate change. Human-caused climate change is greatly decreasing the amount of snow and ice, especially in the Northern hemisphere. As temperatures increase, ice and snow melt increases, replacing reflective snow with heat absorbing dirt. This creates a positive feedback loop as a darker Earth absorbs more heat and increases global warming even more. The albedo is an important ecosystem services that the cryosphere provides.





This figure shows the global temperature increases. The greatest increase occurs in the north. This can be partially attributed to the decrease in albedo in this region.

As ice caps melt, an excess amount of water becomes available. No longer frozen and stored, this leads to a rise in sea level. If all the glaciers were to melt today the sea level would rise a reported 230 feet (NSIDC). When water melts it also expands. This is why the cryosphere is so important. It holds water much more efficiently than oceans and lakes. As we lose this efficient storage, we have a rise in sea level because of the ice melting, and also because as the water heats up it expands. A loss of these storage systems would also have negative effects on supporting ecosystem services as well. Snow and glacier melt provide water for agriculture and drinking water as well as recharging aquifers. This becomes increasingly important as water is consumed at higher and higher rates on a global level.

Many scientists are studying the changes currently going on in the Arctic. The melting of ice sheets and decrease in snow levels year after year can be plainly seen in figures such as the one below. It is no longer a question of whether or not loss of ice caps is an issue, it is how long do we have and what are we going to do.
 
The extreme recession of the Greenland ice sheet. Glaciers, ice caps, and seasonal ice are good indicators of environmental change as they react quickly when effected. If loss of these resources is the first thing to happen, what else is to come?
 
Ted video by James Balog who studies ice-loss. The best visuals start around 7min in, but overall a good explanation of the issue.
This video has some beautiful visuals that highlight the cultural value of the cryosphere. While glaciers and snow are important for ecosystem services, they also have an intrinsic value. Even if you do not dream of ever going to the poles, you probably still enjoy skiing or hiking snow-capped mountains. No one wants to damage this resource and yet we are knowingly doing so every day. Sadly, the intrinsic value of the cryosphere is not enough to save it. It is possible that we need to put monetary value on it if we are to slow it's decline.

What are we going to do? Snow and ice provide key ecosystem services that we currently ignore. One group is suggesting that we give Arctic sea ice an economic value. Do you think that will work? What value would you give the cryosphere? What other values other than ecosystem services do you think ice and snow have?

Increasing Earth's albedo by changing how we build is one viable option. This can be done with reforestation, decreasing the amount of pavement, and by installing reflective or white roofs. It is possible that this could help slow the loss of ice and snow, but it will not be enough if we continue living as we do.

Daily (2009) argues that we need to monitor and give value to ecosystems services so that the individuals, corporations, and governments that create the problem will pay the price of the damage. To do this she proposes the Natural Capital Project, which uses a value system for ecosystem services to aid in policy and decision making. This project uses stakeholder involvement to find realistic alternative scenarios for the future. Daily argues that first of all the science of ecosystem services needs to increase rapidly and that "ecosystem services must be explicitly and systematically integrated into the decision making by individuals, corporations, and governments"(Daily, 2009). Daily acknowledges that price alone will not completely solve the problem, but that it will help people stop discounting the future. You can read more about the Natural Capital project here.



This figure shows how the Natural Capital Project gives value to ecosystem services. It considers all the types of ecosystem services; provisioning, regulating, cultural, and supporting. This model also considers biodiversity of species and habitats.

Now that you know what the cryosphere is doing for you what are you going to do for it?




Citations:
"Ecosystem Services of Arctic Sea Ice Need Urgent Economic Valuation." PRWeb. Vocus PRW, 3 June 2011. Web. 18 Apr. 2012. <http://www.prweb.com/releases/2011/6/prweb8525893.htm>.

Daily, Gretchen C., Stephen Polasky, Joshua Goldstein, Peter M. Kareiva, Harold A. Mooney, Liba Pejchar, Taylor H. Ricketts, James Salzman, and Robert Shallenberger. "Ecosystem Services in Decision Making: Time to Deliver."Frontiers in Ecology and the Environment 7.1 (2009): 21-28.

"Facts about glaciers." National Snow and Ice Data Center. Web. 21 Apr. 2012. <http://nsidc.org/cryosphere/glaciers/quickfacts.html>.

Guitarfreakg290. "Planet Earth Sigur Ros Glosoli." YouTube. YouTube, 16 Oct. 2007. Web. 18 Apr. 2012. <http://www.youtube.com/watch?v=4HqcjgJCDuw>.

"James Balog: Time-lapse Proof of Extreme Ice Loss." TED: Ideas worth Spreading. Web. 18 Apr. 2012.<http://www.ted.com/talks/lang/en/james_balog_time_lapse_proof_of_extreme_ice_loss.html>.

"Global Outlook for Ice and Snow." United Nations Environment Programme (UNEP). Web. 21 Apr. 2012. <http://www.unep.org/geo/geo_ice/>.



Monday, April 23, 2012

Climate Change Isn't Bad For Everybody, Yet


Sea Thimble (Linuche unguiculata) Jellyfish Bloom. Photo Credit: devildiver


It is easy to characterize global climate change as a series of disastrous effects that negatively impact every species on our planet. However, some species are actually benefiting from rising global temperatures. Several jellyfish populations around the world are exploding due to, according to many researchers, climate change! However while one species thrives it can dominate the ecosystem, and cause negative secondary and tertiary effects in the ecosystem by lowering biodiversity. The explosion of jellyfish populations, which in turn cause a significant loss of biodiversity, is an example of the immense and unpredictable impacts caused by climate change.
Jellyfish species have a huge effect on global ecosystems because they can be found everywhere and are a central part of every food web. Jellyfish are members of the phylum Cnidaria. They can be found in every ocean and they span all oceanic environments including the intertidal zone, the open ocean photic zone and hydrothermal vents. Jellyfish are ecologically significant as a major predator and food source. Jellyfish feed primarily on zooplankton, comb jellies and other jellyfish. As some species have grown in numbers and individuals have grown larger in their longer life spans, jellyfish have also begun to prey on some fish and crustacean species and many roes (fish eggs). Jellyfish are also preyed upon by larger fish and sea turtles. 

Example food web for Jellyfish species. Photo Credit: SCF Faculty

The niche fulfillment of jellyfish, the role they play in an ecosystem, is kept in check by predation and prey availability. Despite this balance some jellyfish populations have exploded in the last few decades. The increase in jellyfish leads to a decrease in other organisms and an equilibrium shift in the food web. Over an extended period of time these ecosystem effects lead to instability of the food web and lower biodiversity. Such large populations are also considered economically problematic for humans because they clog fishing nets, they clog hydro power plant generating systems, and they can cause injuries to professionals and recreationalists alike (Moeller, 1984). The rapid increase of jellyfish populations is predominantly attributed one of two causes: over fishing or climate change.  
Several studies have looked at climate change as a possible cause for jellyfish blooms (Brodeur et al., 2008; Mills, 2001; Hare and Mantua, 2000; Purcell, 2005). Most of these studies are conducted in the North Pacific Ocean and Bering Sea because these two regions “appear to filter climate variability strongly, and respond nonlinearly to environmental forcing,” meaning that these areas are strongly affected by climate change and that the affects are exponential (Hare and Mantua, 2000). In this way jellyfish blooms in the Bering Sea are a way to observe and measure climate change. 
Climate change impacts jellyfish populations because more extreme seasons can lead to increased zooplankton and phytoplankton food sources for jellyfish which ultimately supports seasonal reproductive blooms of jellyfish that grow to dominate ecosystems (Mills, 2001). These blooms have the greatest impact when a non-native jellyfish species begins to dominate its new environment and becomes a successful invasive species.Though blooms are a common feature of jellyfish life cycles, their frequency and size has increased for a few jellyfish species so dramatically that the biomass of the population is dominating the ecosystem. The problem is not that the jellyfish populations are increasing. By becoming a dominant species in an ecosystem jellyfish are outcompeting other species for resources like food and space, forcing some species out of a community, and lowering the community biological diversity. This process is what scientists call a "trophic cascade effects" an effect that we can expect to see from human influences in diverse communities (Folke et al., 2004). 

Many communities where jellyfish are blooming were once fish dominated. When we humans attempt to fish in these locations now we are directly affected by increases in pellyfish populations, falling biodiversity, and the disappearance of species we once relied on. Photo Credit: Eating Jellyfish.

For a list of jellyfish blooms around the world check out the Monterey Bay Aquarium "Jellywatch"

Not all of the effects of global climate change may be positive for jellyfish species. Warmer water temperatures increase metabolism and therefore asexual reproduction, but some jellyfish species, especially those in arctic waters may soon find themselves in conditions that exceed their temperature thresholds. In such cases global climate change can lead to the depletion or elimination of some previously flourishing jellyfish species (Purcell, 2005). Even for species that are currently thriving due to climate change, the climate may change too quickly for species to evolve. The ability of any species to succeed will be impossible to predict.
Jellyfish are a model for how human activities are causing far-reaching impacts. Many of the researchers, fishermen, and politicians who find themselves directly affected by recent jellyfish blooms are calling for jellyfish to be hunted and removed from the oceans, but this will not solve the problem. The exploding populations and subsequent loss of biodiversity are indicative of climate change. Rather than treat the symptoms of biodiversity loss, we must treat the causes, and stop the same patterns of biodiversity loss from recurring and spreading across the planet.

For more information on current research concerning jellyfish and biodiversity:

Works Cited