Wiring food webs at Lake George
Nov12

Wiring food webs at Lake George

A collaborative project at Lake George, NY, merges sensory, experimental, and natural history data to develop a better model for environmental monitoring and prediction in lake ecosystems around the world. Guest post by Matt Schuler, a 2013 ESA Graduate Student Policy Award winner currently working as postdoctoral researcher in Rick Relyea’s lab at Rensselaer Polytechnic Institute in Troy, NY. The clear waters of Lake George offer an unobstructed view of the claw-like Ponar Grab Sampler as it reaches the sandy lake bottom, 15 feet below our boat. Kelsey Sudol, an undergraduate from Rensselaer Polytechnic Institute (RPI) pulls sharply upward on the rope attached to the grab sampler, triggering a spring-loaded mechanism. The trap clamps shut around the soil and invertebrates that live in and on the soil, and she draws them to the surface. After we have separated mollusks, arthropods, and insect larvae from the soil with a sieve, this will be one of 30 samples taken from around the lake each month. We will use the data from these samples to understand how invertebrate biomass, diversity, and composition change across space and time. Our invertebrate surveys are part of a food web study that is measuring the complex interactions of the organisms living in Lake George, from the smallest plankton to the largest lake trout. However, measuring and modeling the food web of the 44-square-mile lake is only one component of the Jefferson Project at Lake George. The Jefferson Project is a collaborative, interdisciplinary effort between RPI, IBM, and the FUND for Lake George. Researchers in ecology, engineering, computer science, and the arts and humanities – among other fields – are working together to build a better understanding of lake ecosystems around the world. The project combines new technologies, including an Internet of Things (IOT) computational platform, with observational and experimental data, in developing a new model for environmental monitoring and prediction. The IOT computer platform captures and analyzes abiotic data from a series of “smart” sensors located in and around the lake. The sensor data are combined with food web data and experimental data to form a comprehensive picture of how Lake George functions as a complex ecosystem. This new model can be emulated around the world, helping to redefine how we monitor ecosystems, understand the impact of human activities, and provide insight for the protection of freshwater resources. These lofty goals would not be possible without 35 years of water quality and chemistry monitoring data collected by researchers at Rensselaer’s Darrin Freshwater Institute, with support from The FUND for Lake George. Those data indicate that the water quality of Lake George is changing – with noticeable increases in salt, algae,...

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Managing non-native invasive plants

 This post contributed by Terence Houston, ESA Science Policy Analyst Many invasive species can have a domino effect of throwing an entire ecosystem off balance by diminishing native plant or animal species that function as an important resource for both natural ecosystems and human communities. According to the Nature Conservancy, the estimated damage from invasive species worldwide totals over $1.4 trillion, five percent of the global economy. Invasive species that have gained notoriety in the United States include the Burmese python, Asian carp, Northern snakehead fish,Asian tiger mosquito, emerald ash borer and  brown marmorated stink bug. Non-native  invasives from the plant kingdom can be just as damaging, if not more so. Invasive plant species have the ability to reduce the amounts of light, water, nutrients and space available to native species in an ecosystem. Their ability to affecthydrological patterns, soil chemistry, soil erosion and fire frequency can also have disastrous economic consequences for human society, particularly the agricultural industry. Federal management of invasive species is primarily handled by the United States Department of Agriculture along with the National Park Service.  According to the U.S. Forest Service, invasive exotic plants constitute eight to 47 percent of the total flora of most states in the nation. Of the approximately 4,500 exotic species currently in the U.S., at least 15 percent cause severe harm. Examples of the detriments of invasive plants include alteration of food webs, degradation on wildlife habitat, changes of fire and hydrological regimes and increases in erosion rates. The Forest Service estimates that the United States spends approximately $145 million annually in its attempt to control non-native invasive plants. In a recent edition of the Ecologist Goes to Washington podcast, ESA Graduate Student Policy Award winner Sara Kuebbing discusses her work on invasive plant species at the University of Tennessee in Knoxville. In addition, Kuebbing serves on the Tennessee Exotic Pest Plant Council (TN-EPPC). Her work has included some of the most problematic invasive plant species in the state of Tennessee and the greater United States. During the podcast, Sara touches on her research and efforts by TN-EPPC and affiliated state entities to educate communities on invasive plant species and manage both existing and potential threat species. Perhaps among the most renowned invasive plant species is kudzu, which currently inhabits 30 states and the District of Columbia. According to scientific studies, kudzu’s nationwide invasion costs about $100-500 million per year in forest productivity loss. Kudzu can grow on top of structures and even other plants, including trees, basically suffocating them by obstructing their access to light and other necessary resources.  Power companies spend about $1.5 million annually to control...

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When it comes to economics, diversity is key

A study published this week in Nature compared the U.S. economic downturn with a current ecological issue: a decline in biodiversity. In the study, economist Andrew Haldane of the Bank of England and zoologist Robert May of Oxford University basically described the financial system as having similar weaknesses as a monoculture. That is, if all banks are run equally, they are more susceptible to a uniform crisis; much in the way that a pest invasion would have a farther-reaching impact on a plot of land with all of the same species. According to a Scientific American article, “One way to combat this issue is to establish more self-contained “nodes” as has been employed in forest management and even computer networks, so that if one element takes a hit, it doesn’t take down the entire system.” As Sarah Zielinski explained in today’s Surprising Science post, “There are lessons to be had from the world of ecology, say Haldane and May. We could be promoting and managing ecosystem resilience better by requiring banks to have a larger proportion of liquid assets on hand in case of some sort of shock to the system. Taking a lesson from epidemiology, we could focus on limiting the number of ‘super-spreaders’ within the network; but instead of quarantining infected individuals we would somehow limit the number of ‘super-spreader institutions,’ those banks more familiarly labeled as ‘too big to fail.’” Discover’s blog 80beats implied that the current structure could be affected like a trophic cascade: “Modern ecologists recognize that the failure of key species could cause non-linear, cascading ripples that cripple a whole ecosystem.” Some might propose that these comparisons oversimplify the financial system; however, the overall recognition that industry could draw on ecological science to reevaluate such a complex network is a valid argument to make. “Whether or not experts agree that biology is a useful lens through which to study financial markets, Haldane and May suggested that financial regulation is already ‘following in the footsteps of ecology, which has increasingly drawn on a system-wide perspective when promoting and managing ecosystem resilience,’” concluded the Scientific American article. Photo Credit: Dirk...

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The silent force in the food web

Addition of parasites (red spheres) visibly increases connectivity of species in this representation of an Arctic food web. Studies of food webs fascinate community ecologists. There seems to be a never-ending supply of interactions to observe, analyze and use in predictions. From the largest apex predators, feeding once a week, to the smallest alga, constantly converting sunlight to energy, there’s a kind of wonder in the idea that all living things are connected. In truth, however, ecologists are just beginning to realize that in this picturesque painting of a community in harmony, some less cuddly players are conspicuously absent: parasites. In the May issue of the Journal of Animal Ecology, Per-Arne Amundsen of the Norwegian College of Fishery Science and his colleagues wanted to know whether including parasites in a food web would significantly alter the connectivity of the web itself. The connectivity is the proportion of possible interactions among species that are actually realized in the food web.  These numbers are usually low, since the possible number of connections equals the square of the number of species – if there are 20 species in a community, there are 400 possible connections. The authors examined a lake community where the interactions among species are especially well known.  They then produced a different food web that included parasites living within organisms in the original food web, and compared the two.  As expected, the number of connections increased. Predators often acquire parasites by preying on infected organisms; the authors found that each of the parasite types they studied was ingested by one-third of the free-living organisms. It’s well-known that parasites are ubiquitous within the food web, but, as pointed out in a commentary in the same issue, ecologists are at the point where they’re still talking about including parasites in food webs, but most are not actually doing it. The commentary, by Andrew Beckerman and Owen Petchey of the University of Sheffield, UK, also notes that another emerging line of research will be the study parasites’ effects not only on their hapless hosts, but also on each other. Amundsen, P., Lafferty, K., Knudsen, R., Primicerio, R., Klemetsen, A., & Kuris, A. (2009). Food web topology and parasites in the pelagic zone of a subarctic lake Journal of Animal Ecology, 78 (3), 563-572 DOI: 10.1111/j.1365-2656.2008.01518.x Beckerman, A., & Petchey, O. (2009). Infectious food webs Journal of Animal Ecology, 78 (3), 493-496 DOI:...

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