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2016 November

Oysters and Ecology: An Overview

Liz Clift

Recently, I wrote about the tradition of oyster stuffing—and the reality that some people eat oysters at all (not to yuck your yum, as the youth I used to work with would say, but it bears repeating: ew!).

In this blog, which is part of a series on bivalves, I’m going to focus more on the ecology of oysters. We’ll start again in New York. In the last blog, you’ll remember me saying that oyster production in New York peaked between 1880 and 1910, which was part of the “progressive era” in American history—a time categorized by historians as a period of modernization of natural resource management (among other things). However, this wouldn’t help oysters.

As oyster populations decreased, the bivalves were no longer able to filter all the water in New York Harbor (an adult oyster can filter about 40-50 gallons of water a day), and toxicity became a concern. By 1927, the last oyster bed in New York was closed due to health concerns, and there weren’t any improvements in the health of oyster beds until the 1972 Clean Water Act (CWA). Nearly 45 years later, however, the oysters of New York Harbor are still too polluted to eat and dredging can further complicate oyster health by stirring up centuries worth of pollution that has settled onto the harbor floor.

Overharvesting and high levels of pollutants aren’t the only threat to oysters. Warmer ocean temperatures are leading to ocean acidification—higher levels of carbon dioxide (CO2) are present in the water—which can prevent the shells of young oysters from solidifying. In the previous blog, I talked about pathogens which also impact oysters—including Vibrio, MSX, and dermo—so I won’t rehash that here, but warmer waters can mean that these diseases are spreading beyond their historical presence. In addition, oysters still have to deal with their natural predators, which in addition to people include:

  • Fish (especially for young oysters);
  • Birds;
  • Blue crabs;
  • Sea otters;
  • Sea stars (which use pressure* to force open the oyster’s shell); and
  • Snails, such as the Atlantic oyster drill.

The plight of oyster is so bad that portions of the East Coast only have 1% of their historic natural oyster population—despite efforts to repopulate oysters. Fortunately, New York and many other areas are taking oyster repopulation serious. This is good because oyster reef abundance has decreased approximately 85% globally in the past century. Oysters help filter pollutants from water (though they can do nothing about heavy metals and PCBs, except absorb them into their bodies, which can render them dangerous to humans). Oyster reefs can also help stabilize sediments and slow wave-induced erosion, which can make a big difference in areas where coastal loss is a problem.

Although restoration efforts are underway up and down the East Coast and in other parts of the world, it will likely be years before oyster populations are restored enough to provide the same level of various ecosystem services that they once provided—and that’s assuming oyster harvesting is well-managed, and that diseases that can affect oysters don’t boom alongside these restoration efforts.

These restoration efforts, like all restoration efforts, should also include monitoring. This can help evaluate the state of the habitat, detect recruitment and survival rates, understand how the ecosystem is functioning, and recognize the interaction of species in and near the reefs.

*This video shows mussels, not oysters, but you get the idea.

Project Update: Colorado Emergency Watershed Protection

As we move into the final month of the year, it’s time to offer an update on our work with the Colorado Emergency Watershed Protection (EWP) project. This emergency recovery work is being completed in response to the devastating September 2013 floods, which impacted counties across Colorado’s Front Range. The program provides financial and technical support to community-based project sponsors to reduce erosion and impacts from future flooding, protect streambanks, remove debris, and more.

Great Ecology is working with state and federal agencies, counties, design teams, watershed coordinators, and landowners in order to design revegetation plans for 46 EWP projects. We have completed initial revegetation plans for 23 sites, and installation has started on 2 of those sites, which included overseeing approximately 445 volunteers who participated in planting days as part of the revegetation efforts. In addition to the 46 revegetation plans, Great Ecology is on the Technical Assistance Team and providing design reviews for the remaining 29 EWP projects. Great Ecology is also providing oversight and developing protocols to the Colorado State Forest Service Nursery for collection and propagation of ecotypic native plants to be used for revegetating all 75 EWP projects.










A Brief History of Oysters as Food

Liz Clift

It’s nearly Thanksgiving, and for some of us (especially if we have some New England traditions in our background) that may mean oyster stuffing. This tradition is likely a carryover from England, where as early as 1685, oysters were being used in stuffing for a variety of meat dishes.

If you’re like me, you’re thinking ew, gross. If you’re like our Senior Managing Ecologist, Randy Mandel, it’s one of your favorite parts of Thanksgiving.

Oysters can be pretty expensive though—East Coast oysters are typically about $2/each and while jarred oysters are generally a little cheaper, they’re still pricy. So how did the tradition of oyster stuffing carry over from England (if that is, in fact, where it came from)?

In the US, oyster production reached its peak between 1880 and 1910. During this period, the US produced up to 160 million pounds annually (today we produce about a quarter of that amount)—more than all other countries combined—and some biologists think New York harbor, which hosts the eastern oyster (Crassostrea virginica) may have once contained more than half of the world’s oyster population. During the height of oyster production, they cost less than beef, poultry, or fish, and so were consumed by the masses—and even sold by street vendors. So many oysters were consumed that New Yorkers even paved Pearl Street with oyster shells and used them in the foundations of buildings. With this knowledge, it’s easy to hypothesize that folks mixed the plentiful and inexpensive oysters with some bread and spices, and voila, a continued tradition of oyster stuffing.

Today, that level of consumption seems unfathomable. Even during this peak production period, oyster populations were under siege from overharvesting. As early as 1658, back when New York was still New Amsterdam (and boasted a population between 6,000-9,000), there were rules in place that regulated when and from where oysters could be harvested because of worries about depleting this food source. Now, the oyster is functionally extinct in New York Harbor (it’s estimated, oysters once covered 22,000 acres of the Hudson River estuary).

The Billion Oyster Project hopes to change that—and to plant one billion oysters in New York Harbor by 2035. This isn’t just a project of planting oysters though—it is also an educational system designed to teach thousands of citizens, including students, about the Hudson River estuary. These oysters stand to provide major water quality services to the estuary system (but that’s another—and forthcoming!—blog).

You won’t be able to eat these oysters though—they will be filled with far too many pollutants, including heavy metals. This susceptibility of oysters to environmental pollutants is one of the things prompting oyster farmers to, well, farm oysters. But farmed oysters are also susceptible to some of the same pathogens as their wild-raised kin. Bacteria called Vibrio can cause severe illness (or even death) in people who eat shellfish or swim in ocean waters where the bacteria is present. Vibrio is, in fact, one of the reasons for that old saying “only eat oysters in months with an ‘r,’ which is to say, the colder months of the year because warmer waters can cause it to spread more easily.

Today, a fair amount of research and oyster-farmer education is being done on how to minimize the risk of Vibrio bacteria—but as oceans warm, and the bacteria moves further north, the risk becomes more prevalent in markets where it hasn’t been (as much of) an issue before (Shaw, et al. 2014).

The aquaculture industry has a vested interest (and those individuals who don’t, should) in researching Vibrio as well as two warmer water diseases that can decimate an oyster crop (MSX and Dermo, neither of which has an impact on human health). The research, and its findings, can be especially important for small oyster farms.

Small farms can be more vulnerable to the economic impact of losing many oysters or to developing a reputation for making people sick. This may be especially true for these small farms that are marketing themselves more like “boutiques,” which make efforts to stand out based on the flavor of the oyster.

So, what creates oyster flavor? The merroir (like a wine’s terroir)—climate, geology, water quality, and water temperature—the oyster grows up in.  These factors vary depending on where it was raised and the time of year it was harvested. One shellfish company (and this is no endorsement of the company or the accuracy of the wheel—I don’t eat shellfish, just find them fascinating!) has even put together an extensive flavor wheel for oysters (as well as an aperitif pairing guide). There are, very literally, entire books you can read about the taste of oysters.

So, regardless if you like oysters in your stuffing, or on the half shell—or if you prefer them alive and filtering our water—it’s important to consider how the oyster’s environment impacts its health, likelihood of survival, and if you’re an oyster-eater, how much you’ll have to pay for an oyster and how it’ll taste.

Keep an eye out for a follow-up blog, coming soon, on the ecology of oysters.


Shaw, K.S., J.M. Jacobs, B.C. Crump. 2014. “Impact of Hurricane Irene on Vibrio vulnificus and Vibrio parahaemolyticus concentration in surface water, sediment, and cultured oysters in the Chesapeake Bay, MD, USA. Frontiers in Research Topics. 5.204.

Private Investors’ Impact on Mitigation Banks

Liz Clift

If I say wetlands, do you think of the Everglades?

For a lot of us living in the United States, that is exactly what we think because those are the wetlands featured again and again in those half-hour documentaries that we watched in science class. The Everglades, located in the southern portion of Florida, begins with the Kissimmee River and Lake Okeechobee. Water leaves Lake Okeechobee during the wet season and forms a 60-mile wide river that flows for more than 100 miles to Florida Bay.

But while the Everglades are certainly well known, there are many wetland areas in the U.S. – including around the Chesapeake Bay, the Delaware Bay, the San Francisco Bay Delta, the Mississippi River Delta, and the Great Dismal Swamp, as well as smaller wetland areas like prairie potholes, fens, vernal pools, and playa lakes. Wetlands tend to have high levels of biodiversity, because in many ways they serve as an ecotone—a place of transition between two biological communities, where life extends itself as far as it can either into the water or out from it.

Work is being done to preserve these important ecological habitats. Between the mid-1950s and the mid-1970s, natural processes (such as large storms) and human activities resulted in the loss of more than 450,000 acres of wetlands each year. In partial recognition of this alarmingly high wetland loss rate, the passage of the Clean Water Act in 1972 put the U.S. federal government in the business of protecting surface waters from pollution and fill, including wetlands. By 2008, 36 years after the passage of the passage of the Clean Water Act, hundreds of thousands fewer acres[1] were being lost each year.

The decrease likely occurred because during the George H. W. Bush presidency, the act was updated to include a provision mandating “no net loss” of wetlands. In short, this means that if human activities directly destroy wetlands, actions must be taken to restore wetlands within the same watershed. It does not account for human activities that don’t have a direct impact on wetlands (such as upland development), or changes to coastlines through storm surges and sea-level rise.

The “no net loss” provision—along with a growing recognition of the ecosystem services provided by wetlands—has created fertile ground for the development of “mitigation banks” to finance wetland restoration as a creative way to help developers maintain compliance with the “no net loss” policy. These banks, by restoring wetlands, generate credits that developers can purchase to offset damages caused by their projects.

The money received from developers is then turned around to repay investors, who front the money for the banks’ restoration work, along with a generous return. A 2014 report on conservation investments by NatureVest and EKO found that environmental credit-generating projects generate internal rates of return of between 10 and 14.9%. A recent article at Forbes argues “private capital is key to large-scale environmental protection and restoration” because government funding is becoming more constrained and there is little philanthropic money available for these projects. The White House also recognizes the need to importance of private investors—and incentivizing them to invest in what is still a fairly new market. Earlier this year, the White House released a strategy document, “Leveraging Innovation to Boost Private Investment in America’s Natural Resources,” which promotes policies that reward:

  • Flexibility;
  • Outcome-focused conservation;
  • Financing methods to kick-start conservation markets;
  • Technologies that reduce the cost of measuring and verifying conservation outcomes; and
  • Enable collaboration across landscapes.

Wetland mitigation banking, which is the most mature of the ecosystem markets, still has room for growth. There are currently more than 2,900 mitigation banks (which focus on wetlands) and more than 100 conservation banks (which focus on other resources). These banks protect valuable ecosystem services, including providing habitat for threatened and endangered species, water purification, shoreline stabilization and storm surge buffering, flood protection, and groundwater recharge. However, developers can only purchase credits from banks within a certain geographic “service area”, or market. There are, therefore, still places in the U.S. that are not serviced by wetland mitigation banks that could likely use them.

From an economic perspective, one hope is that if outsourced compliance, such as that which comes with mitigation banking, can be proven effective in other areas, more private investors can be attracted to those—and other—ecosystem markets. Private investors may also be encouraged by a November 2015 Presidential Memorandum that created more predictability and incentives to encourage private investments. The Presidential Memorandum came with the anticipation that these additional private investments would grow the estimated 126,000 jobs and $9.5B in direct economic activity that was already centered around restoration of natural resources within the U.S.—providing another 95,000 jobs and $15B in economic output.

Great Ecology is a key player in this growing mitigation banking industry, and has recently partnered with Tellurium Partners, PBC, a mitigation banking investment firm, which works to locate and develop strategic mitigation banking opportunities as part of their mission to:

“restore and conserve wetlands and natural habitats, and to provide public agencies and private parties a method for complying with governmental mitigation requirements for the disturbance of ecological resources.”

Great Ecology provides consulting support for mitigation banks including site assessment, financial analysis, permitting and design, monitoring and maintenance, long term management, construction oversite, and operation and credit sales.  Tellurium Partners owns, operates, finances and invests in the mitigation and conservation banks.

Great Ecology founder and President, Dr. Mark Laska, is on the Board of Directors of the National Mitigation Banking Association and has participated in their annual meeting since 2006.  The upcoming meeting in May 2017 will celebrate the organization’s 20th anniversary, and Great Ecology will have a booth at the conference.

If you’re interested in learning more about mitigation banks, check out our Mitigation Banking Services page or Tellurium Partners’ Mitigation Banking Guide.

[1] Much of the ongoing loss is due to coastal wetland losses driven by subsidence and sea level rise, and not any one collection of permitted development activities.

Great Ecology Welcomes Chris Loftus!

Great Ecology is pleased to welcome Chris Loftus, RLA (back) to Great Ecology! Chris has worked on projects throughout Colorado and the West, including several award-winning designs. His past project experience includes planning and design of parks, trails, and open space; neighborhood and community master planning; innovative stormwater design solutions; urban streetscape design; and ecological restoration. Chris will collaborate with Great Ecology’s ecologists, designers, and planners to provide regenerative ecological design solutions for a variety of project types and scales.

He serves as Vice President of Programs for the American Society of Landscape Architects (ASLA) Colorado Chapter and on the Ecology + Restoration Professional Practice Network (ASLA) leadership team. He is a member of the Colorado Riparian Association, the Colorado Native Plant Society, and is a Council of Landscape Architectural Registration Boards (CLARB) Certified Landscape Architect.

Chris holds a Bachelor of Science in Environmental Studies from University or Oregon and a Bachelor of Science in Landscape Architecture from Colorado State University.

Great Ecology to Attend the First Green Business Forum for Asia and the Pacific


The following information is from the ADB Calendar of Events.


This November, ADB will host its first Green Business Forum for Asia and the Pacific (GBF). The GBF brings together experts, business practitioners, and key stakeholders to share knowledge and identify avenues for promoting green business solutions in the region.

The GBF aims to provide a platform for knowledge sharing and lessons learning on the best policies/incentives, institutional arrangements, and financing modalities that can best support rapid green business development in the region.


ADB hosts its First Green Business Forum in recognition that green business is a key component and mover of green growth. It is a friendly gathering where green business practitioners and professionals can have an open dialogue and share their best ideas and experiences. Participating in the Green Business Forum enables you to become part of the increasing momentum towards green growth.


  • Showcase a number of best practice examples to illustrate early movers and successes in emerging green markets across the region;
  • Share and learn from the most effective policy frameworks and market based approaches promoting green business;
  • Help better understand why some countries are able to foster green business growth faster than others, and identify key factors for success;
  • Stimulate investments in emerging green business space;
  • Enable partnerships and collaborations for green business


In Vino Veritas – In Wine there is Truth

By Marlene Tyner-Valencourt

60% of Americans say climate change is important to them, and for good reason. Climate change is critical from the perspective of national security, domestic safety, and ecological stability. But what you may not know is that climate change is also having significant impacts on global economic trends and regional culture. This is especially apparent in the viticulture, or wine grape, industry.

Climate change affects the distribution of temperature and precipitation patterns across landscapes. Wine grapes are particularly sensitive to both of these climate factors. That’s why wine grapes have been grown in very specific geographic areas for thousands of years – the terroir, or climate and soil conditions, have been just right for growing grapes that make premium wine varieties. The sensitivity of these grapes to even the smallest changes in climatic factors also means they make a useful ‘canary’ when assessing the impacts of climate change on the ‘coal mine.’

During graduate school, I was fortunate to work with Lee Hannah, conservation ecologist and Senior Researcher in Global Change Biology, and his research group on an effort to understand how climate change may impact the global distribution of wine grapes. Hannah et al. (2013) defined the climatic ‘envelope’ of temperature and precipitation ranges that best support viticulture, and then looked at climate models to understand where these specific temperature and precipitation ranges will be found around the world in the future. What our group found was that many of the places that are the current centers of wine production – southern Europe, South America, and South Africa – will lose 25% to 73% of area suitable to grow wine grapes by 2050. The climate envelope is predicted to shift to places where wine is currently not grown or is just starting out, such as North America’s intermountain west, northern Europe, and coastal New Zealand.

Indeed, we are already seeing evidence of this agricultural shift in the global markets today. Analysts are expecting a 5% reduction in global wine production for 2016, with output among the lowest in twenty years. The hardest hit areas include France (12% reduction), South Africa (19%), Chile (21%), and Argentina (35%), meaning that nice Malbec you like at Trader Joe’s is likely to become much more expensive. If that’s the case, check out wines from Australia, which saw a 5% increase in production, or New Zealand, which saw their production increase by 35%. It’s worth noting that these production trends follow Hannah’s predictions regarding the global shift in wine production.

The International Organisation of Vine and Wine (OIV) blame extreme El Nino-driven rain events for the impacts to the South American wine industry, but steadily increasing temperatures have been impacting grape production globally for some time. For example, between 1993-2009, Australia’s wine grapes ripened an average of 1.7 days per year earlier than historical phenological maturity times (Webb et al. 2011), affecting the quality of the vintage along with causing logistical challenges at regional processing facilities.

Additionally, climate change not only affects precipitation patterns, but also long-term access to water resources. Depending on the wine you’re drinking—where it was grown and how it was produced—a typical 4-ounce pour of wine uses somewhere between 14.2 gallons and 51.5 gallons of water. This is a serious issue for California, the largest wine producer in the US, as the state enters its sixth year of drought. Other climate change-driven risks to the wine industry include sea level rise at key coastal production areas, such as the Bordeaux region of France, parts of Portugal, and New Zealand, as well as increasing prevalence of insects and insect-borne crop diseases in viticulture stands (Mozell and Thach 2014).

New Zealand, 2006

New Zealand Vineyard

Wine is not the only crop affected by climate change. Analysts and policy makers are projecting significant impacts to the coffee, chocolate, and corn industries, and predicting shortages, higher prices, and shifts in the distribution of global production of these crops and secondary products, like beef, over the next few decades. In other words, climate change is having very real effects on foods that millions of Americans eat every day, and is going to make our favorite bottle of Pinot Noir, coffee drinks, and steak dinner way more expensive really soon. 60% of Americans say climate change is important to them, but 100% of Americans will feel its impacts at the grocery store.