How human exploitation has reshaped a marine ecosystem

Home » Scientific American Magazine » March 2012

The Dwindling Web

By John Matson  | March 13, 2012 | 2

Humans have harvested the sea for tens of thousands of years, but only in the past few centuries have we begun to take a big toll on ecosystems. The two food webs below show predatory relationships among life-forms in the northern Adriatic Sea. Each web comprises humans, their prey and the prey of humans’ prey, distilled into groups of species.

The webs, produced by Jennifer A. Dunne of the Santa Fe Institute from evidence compiled by Heike K. Lotze and Marta Coll of Dalhousie University in Hal­i­fax, show that as recently as 1800 none of the Adri­at­ic species groups had yet grown “rare,” or dropped below 10 percent of their former abun­dance. By the late 20th century, when the global economy had replaced local trade, 10 groups had gone extinct or rare, eliminating them from the webs.

Graphic by Jennifer A. Dunne. Interactive by Ryan Reid.» Watch a video about food webs in this month’s Graphic Science Web Exclusive “Food Webs Trace the Structure of an Ecosystem.”

This article was published in print as “The Dwindling Web.”

Restoration Is Good for Business

Coastal Review Online

03.08.2012

By Howard White

 

A commercial fishermen loads oysters shells to be placed in Stump Sound. Fisherman were paid to help build oysters reef as part of the federation’s federal economic stimulus grant.

A landmark report on conserving our coastal habitats gives all of us concerned with preserving coasts and estuaries a new argument, one that will appeal to new and larger audiences: It’s good for the economy.

“Jobs & Dollars: Big Returns from Coastal Habitat Restoration” tackles the need to protect and restore our coasts from a perspective some have dubbed “coastal capitalism.”

The report shows that public and private investments in coastal habitat restoration not only produce jobs in this cash-and-job-starved economy, but do it at a higher rate than many more touted job sectors, including oil and gas, road infrastructure and green building projects.

The report was prepared by Restore America’s Estuaries, an alliance of 11 conservation organization that formed in 1995 to preserve our nation’s estuaries. The N.C. Coastal Federation is a member.

SOME OF THE REPORT’S KEY FINDINGS

Coastal habitat restoration—that includes things like wetland reconstruction and improvement; rebuilding depleted oyster beds; removal of dams, culverts, and other obstacles to fish passage; tree planting and floodplain reconstruction; and invasive species removal—typically create between 20 and 32 jobs for every $1 million invested. Compare that with road infrastructure projects that, on average, create seven jobs per million, oil and gas at just five per million, and green building retrofits that produce 17 jobs per $1 million invested.

Habitat restoration creates local jobs and brings dollars to local businesses. In one of the report’s case studies, a watershed restoration project in Oregon, 80 percent of the money invested in the project stayed in the county, and 90 percent stayed in the state.

Restoration not only creates direct jobs—people hired to use their skills and equipment to restore damaged wetlands and similar projects—but also stimulates indirect jobs in industries that supply project materials like lumber, concrete and plant materials, and induced jobs in businesses that provide local goods and services—food, clothing, shelter—to restoration workers.

Most importantly, are the long-term economic returns from habitat restoration: tourism and tourist dollars, hunting and fishing revenues, freshwater supplies and, in an economy where house prices have plummeted, increased property values.

In 2009, the federation was one of 55 groups nationwide that received an economic stimulus grant administered by the National Oceanic and Atmospheric Administration. The $5 million grant was used to restore nearly 60 acres of oyster reefs in the Pamlico-Albemarle Sounds region. That $5 million was put to good use: It helped create or protect 150 jobs along the N.C. coast.

Darren Burrus, one of the project contractors and a Buxton resident, had less work for his company in 2009 when the project started. Thanks to the federation’s grant, things started looking up for his small business, Cape Dredging Inc., built oyster reefs off Hatteras Village.

“We’re excited to get back to work, the marine construction business has been slow,” Burrus, a co-owner of the company, said in 2009.  “And having more oysters and fish around will be good for the watermen and oystermen. I love North Carolina oysters.”

 

A barge dumps oyster shells into Pamlico Sound as part of the federation’s stimulus grant.

Another component of the project paid fishermen to plant 40,000 bushels of oyster shell in 19 locations from Ocracoke to Myrtle Grove Sound and Topsail Sound.  This program, which the N.C. Division of Marine Fisheries began in the spring of 2009, provided supplemental income for many fishermen hit hard by the economic downturn.

“The project provides immediate job benefits and enhances ongoing efforts to improve oyster and fish populations, as well as improve water quality,” Louis Daniel, the division’s director, said in 2009.

All of which begs the question: How valuable are our coasts and estuaries to the nation as a whole?

While coastal-estuarine counties make up only 13 percent of the U.S. land area, they generate half the nation’s GDP, and provide 40 percent of all American employment. More than three-quarters of all commercial fishing depends on estuaries, generating an estimated $1.4 billion for local fishing concerns. U.S. coastal wetlands provide spawning grounds, nurseries, shelter and food for 85 percent of waterfowl and other migratory birds. Tourism and recreational pursuits—angling, bird watching, canoeing-kayaking and similar activities—add more than $70 billion to the economy every year.

But despite their obvious value, both ecologically and economically, America’s coasts and estuaries are in trouble.

Historic losses alone are staggering. The report documents that 97 percent of Columbia River salmon are gone. Likewise, 95 percent of all San Francisco Bay wetlands have vanished, sacrificed to development and commerce. The Chesapeake Bay oyster population is down to one percent of historic levels.

Louisiana’s wetlands are in a class by themselves. The state’s coastal wetlands are receding at an astounding rate of one football field an hour. Loss of the state’s wetlands not only threatens lucrative local industries like shrimping and crabbing, but also puts 45 percent of the nation’s oil and gas refining capacity and 43 percent of its strategic petroleum reserves at risk.

Locally, it’s no secret that the loss of North Carolina’s coastal wetlands from erosion, rising sea levels and increasing storm intensities pose a threat to economic interests on the Outer Banks. No less important, though, is the threat these new realities pose to the nearby inland areas and communities that depend on healthy coastal and estuarine ecosystems. Flooded coastal marshes; salinization of aquifers and drinking water; impacts to fisheries and wildlife; and property loss and devaluation due to flooding may be consequences of ongoing threats and loss of North Carolina’s coastal resources.

THE REPORT’S KEY RECOMMENDATION

It is critical that the United States invest in coastal habitat restoration. Not only will it address many of the problems listed above, it can and will provide much-needed jobs—everything from out-of-work commercial fishermen, marina and boat captains, barge operators, and seaside businesses ranging from bait shops to four-star hotels and restaurants—in an economy still hurting from the 2008 crash and recession.

ABOUT THE AUTHOR: Howard White

Howard White is the communications specialist for Restore America’s Estuaries. He has worked on wide a variety of conservation and animal welfare issues over the past 20 years, ranging from manatee and shark campaigns in Florida to national grasslands preservation. He admits to dodging lions in Kenya, rock pythons in the Everglades and caimans in Costa Rica—and loving every minute of it.<  PREVIOUSNEXT  >

Risks to Birds and Wildlife from Offshore Wind Turbines 2011

•UNC‐Chapel Hill Survey of Seabirds and Wildlife for Risk Assessment ‐2011 – funded by Duke Energy

Duke Energy Survey of Seabirds and Wildlife for Risk Assessments
 Pamlico Sound ‐ 98 days of small‐boat surveys from Jan 2010 – Jan 2011 ‐ half in calm (<10 knots), half in windy (10‐25 knots) condition at boat speed of 6 knots
 Potential Pilot site 7‐10 miles out in sound
 Reference site near shore inside of reef
 Coastal ocean shelf: from inlet out to 57‐65 km
 Into Raleigh Bay from Hatteras Inlet – 21 surveys
 Into Onslow Bay from Beaufort Inlet – 4 surveys

Bird Behavior Insights
 Only half the species flew within 26.5‐135.5 m heights swept by rotor blades
 Of those, a small fraction of individuals did, except all 245 scaup
 Some gulls, pelicans, young terns flew over the 22‐m high Bonner Bridge with
little road clearance and dominated road‐kills quantified on the bridge
 Flight paths of passerines in nocturnal migrations that follow Outer Banks still
unspecified – we saw virtually no passerines over water, even at dawn and dusk
 High‐tech instrumentation (radar, thermal, acoustic) may help, but use of air
space is insufficient info w/o behavior
 Seaducks, like long‐tailed, and coastal ducks, like scaup, often raft at night then make twice daily trips to and from foraging sites – on regular flyways?
 Albatrosses that forage at night may have elevated risk
 Only empirical assessments of impacts of operating wind turbines over ocean waters can provide rigorous assessments of true risks

Measures to Reduce Risk to Birds and Bats

 Do not use continuous lighting
 Flashing lights attract fewer migrating birds
 Red lights may be less attractive than white lights
 Reduce or eliminate perches
 The absence of perches, nesting, and roosting sites decreases the
frequency birds and bats closely approach wind mills
 Avoid white colors.  Paint wind mill vanes in high contrast
patterns.
 White attracts insects; increased insect abundances attracts bats
 Test s show that kestrels avoid moving wind mill vanes more readily if
they have patterns painted on them
 Pilot studies and impact studies after installation and operation
of the first wind farm will demonstrate whether other
mitigation procedures are neede

Risks to Birds and Wildlife from Offshore Wind Farms: 2009

BOEMRE NC Task Force
Merged results of two studies with multiple partners: •UNC‐Chapel Hill Wind Power Feasibility – 2009 ‐ funded by the North Carolina General Assembly
•UNC‐Chapel Hill Survey of Seabirds and Wildlife for Risk Assessment ‐2011 – funded by Duke Energy

Charles H. “Pete” Peterson
University of North Carolina at Chapel Hill,

Procedure for Estimating Risk

Interview experts, managers, bird watchers,
fishermen, and duck hunters:
‐ 54 in‐person interviews
‐ 5 phone interviews

Review relevant literature:
‐ 21 environmental assessments
‐ 21 government reports
‐ 40 peer‐reviewed articles
‐ 14 unpublished manuscripts

Accumulate and organize pertinent information:
‐ distributions and temporal patterns of organisms
‐ possible presence of endangered, threatened, or species of concern
‐ specific behavioral responses to structures, noises, and visual cues
‐ distribution of fishery habitat and fishing activities

Estimation of risk

‐ examine accumulated information for patterns and specific concerns

‐ use general ecological data and paradigms to reduce uncertainty

‐ consult with experts again on preliminary assessments

Birds at risk
 Passerines (songbirds) during their nocturnal,
seasonal (fall, spring)migrations
 Threatened and endangered (piping plover, roseate
tern, Bermuda petrel) plus declining species (red
knot, other migrating shorebird species) during
fall/spring migrations and summer/winter residence
 Large‐bodied, slow fliers (pelicans, gulls)
 True pelagic seabirds (albatross) – Gulf Stream risks
 Bats at risk – migrating insectivorous species on land

Avoid High‐Use Sites to Protect Seabirds
 Gulf Stream track range plus buffer around it
 All 3 capes (Hatteras, Lookout, Fear)
 The “Point” where Gulf Stream and Labrador Current
meet and diversity and productivity are high
 Radius of 5 miles around each inlet
 Shallow waters less than 4 m depth
 Localities near any land – separation by at least 2 miles

Ecological Risks to Birds and Bats from WindTurbines Over Water.

As Reported in the OffShore Energy Panel in 1211

Birds and bats represent the organisms presumed to be at greatest risk of harm from wind turbines over water, based upon their distribution and abundance patterns and behavioral responses, and based upon observations made on wind-turbine impacts on land. Summering and especially overwintering waterbirds are ubiquitous in the sounds, and the near-shore coastal ocean out to at least 2 miles is heavily used by fish-eating waterbirds and probably occasionally transited by migratory songbirds and shorebirds of concern. Compared to reported minimum densities of birds on land around an existing Minnesota wind farm of about 600 individuals per km2, the Duke Energy-funded UNC surveys in 2010 demonstrated an average bird density in Pamlico Sound of only 12.9 individuals per km2 and on the transects in the coastal shelf out Hatteras Inlet and Beaufort Inlet of 5.0 individuals per km2. To the degree that abundances imply relative risk, the risks to birds would be judged as much lower over North Carolina’s near-shore continental shelf than over land where wind farms exist. The pattern of bird abundance over the near-shore continental shelf exhibits large declines with distance from the shore, such that bird density declines by about two thirds from the highest density within the first 10 km of the beach to the average of the zone from 10-40 km. True pelagic seabirds remain uncommon and only begin to increase in abundance past the 40 km point as one approaches the Gulf Stream, where true pelagic seabirds and many endangered marine mammals exist in substantial abundance off of North Carolina’s coast. The year-long UNC surveys of birds over the eastern Pamlico Sound and on the continental shelf into Onslow Bay and Raleigh Bay failed to encounter even a single individual of an endangered bird species. No bats were detected even though surveys began at first light and ended at dusk daily. Bird abundance is not the only factor determining risk of encounter with a spinning rotor blade. Behavior must also be considered. Night flying would elevate risk because of the difficulty in detecting the spinning rotor blades. Passerine birds (neotropical migrants) make inter-continental migrations during spring and fall, tracking the coastline along the coastal North American flyway. These migrations occur at night, raising concern about these valued terrestrial species. The UNC year-long surveying detected very few passerines and revealed no evidence that the migratory pathway extended out over the continental shelf into areas that would place these birds at risk from wind turbines. In the Duke Energy study, flight elevations of each species of bird were estimated for replicate numbers of individual birds and compared to the heights swept by a standard 3.6 MW wind turbine (26.5 – 135.5 m). Half the species of birds never flew as high off the water as the minimum height swept by the turbine blade. Of those species whose flight altitudes overlapped the rotor-swept elevations, only a small percentage flew within the risky altitudes. Finally, UNC assessed risks of collision of birds with vehicles crossing the 22-m tall Bonner Bridge by comparing counts of dead birds and of live birds by species. 70 W InD e n eR G Y Re s oU Rc e s Brown pelican and juvenile gulls and terns exhibited higher mortality than other species, implying that they might also exhibit similarly risky behavior around spinning rotors of wind turbines. The only reliable means of determining true risk of bird mortality from encountering spinning rotors blades is to conduct an assessment of impact on an installed wind turbine in the geographic area of concern. Nevertheless, existing evidence implies that risks to birds and bats may be lower, even substantially lower, over the N.C. continental shelf 10-40 km from land than on land where existing wind farms are found. In contrast to the elevated bird abundances in the Pamlico Sound relative to the coastal shelf in the Atlantic Ocean, the patterns in absolute abundances of marine mammals and sea turtles spotted during the UNC 2010 surveys reflect substantially higher abundances in the coastal ocean than in the Pamlico Sound. The coastal ocean sampling revealed 0.41 marine mammals per km2, as compared to only 0.013 per km2 in the Pamlico Sound. Sea turtle abundances were also 35 times higher in the coastal ocean at 0.035 per km2 versus 0.001 per km2 in Pamlico Sound. Consequently, absolute risk of interactions between energy-production facilities and both marine mammals and sea turtles is much greater in the coastal ocean. All the sea turtles observed are federally listed under the Endangered Species Act as either threatened (loggerhead, with a current review of evolutionary separate units for potential endangered status) or endangered (Kemp’s ridley and leatherback), so require special consideration and federal agency consultation wherever a development project poses any potential risk to them. Similarly, marine mammals observed in the coastal ocean include at least one species listed under ESA (humpback whale, and possibly also an unidentified cetacean), and require similarly comprehensive federal agency review of development plans. Obviously, marine mammals and sea turtles do not run a risk of death from encounters with rotating rotor blades of wind turbines. The risk of potential concern to marine mammals, and perhaps also to sea turtles, is a risk of noise, especially during installation of piles, which may be forced as much as 30 m deep into the sedimentary sea floor to stabilize the wind turbine above. Bottlenose dolphins have been observed to retreat to a distance of 10 km away from similar noises, thereby temporarily depriving them of use of that habitat area. If this problem is judged to be serious or if any endangered marine mammal proves similarly sensitive, then mitigation during construction may be required. This could conceivably be achieved by doing the construction during a season of low use by marine mammals or by employing gravity-based foundations on the wind turbines, a more expensive design suitable for sites where the sea floor is hard rather than comprised of sandy sediments. Marine mammals and sea turtles may also be affected by the EM fields around the transmission cables running from the wind farm into shore. Sea turtles are known to navigate back to natal beaches based on detecting and following the earth’s magnetic field. This may imply navigation disruptions from the EM fields – an issue that still needs study. Some fishes also use electromagnetic fields for navigation, communication, or aggression, notably the American (and European) eel, and certain rays and other elasmobranchs. A report 4 prepared as a part of the environmental impact assessment (EIA) for the Cape Wind project in Massachusetts suggests that while the magnitude of the EM and induced electric fields from buried transmission cables may exceed the detection threshold for marine organisms, the 50-60 Hz frequency from an AC cable may be imperceptible because many organisms are only able to detect frequencies of 10 Hz or less. No problem has been reported from existing European wind farms that relates to EM fields and their effects on fish or wildlife. Many positive environmental synergies can be associated with the presence and operation of wind turbines on the nearshore continental shelf. The foundation of each wind turbine is usually stabilized with a rock anti-scour apron, built up 1-2 m from the seabed using large rocks, ideal for creation of habitat for rocky reef fishes. The species of the snapper-grouper complex that occupy rocky reef habitat on the North Carolina continental shelf include some of the most depleted fishery stocks. Provision of new habitat that would occur through construction of the anti-scour aprons would benefit these valuable fish stocks and the fisheries based upon them. The presence of a wind farm on the continental shelf could also facilitate the ocean mariculture industry. There exists strong interest in shellfish and finfish culture on the continental shelf as a means of escaping risk of escalating water-quality problems inside our estuaries and as a means of minimizing environmental effects of finfish-generated wastes, which can be diluted and dispersed in shelf waters with strong currents. Nevertheless, a major impediment to ocean mariculture is solving the problem of how to protect the pens and nets from being damaged by ship traffic. The presence of a wind farm, with its necessarily well-lit, charted, and visually obvious structures, could offer mariculture pens protection from collisions with ships. 4 http://www.boemre.gov/offshore/PDFs/CWFiles/141.pdf71 W InD e n eR G Y Re s oU Rc e s Several large coastal areas offshore in federal waters off North Carolina were identified as locations where wind farms would not pose excessive risk to birds and wildlife. The coastal zone out to at least 2 miles, the areas within a 5-mile radius around each inlet, the three Capes (Fear, Lookout, and Hatteras), “The Point” northeast of Cape Hatteras, all waters shallower than 4 m in depth, and the entire area swept by the Gulf Stream are characterized by unacceptably high risk to birds, sea turtles, and/or marine mammals and are not compatible with the presence of a wind farm. On the remainder of the N.C. continental shelf, wind farms would not pose high risk to birds and wildlife.