Dispatches

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China's new Great Wall is not for the birds

Claire Miller

More than half of China's tidal flats around the Yellow Sea have been smothered by development over the past 50 years, driving migratory shore-birds out of vital resting and foraging grounds. And with construction of the new “Great Wall of China” expected to continue apace, scientists say the tidal flats now qualify as an endangered ecosystem under new IUCN criteria.

The Yellow Sea's primary coastal habitat – tidal flats – extend across northeastern China and along the Korean Peninsula. The flats are home to numerous invertebrates and vertebrates (including fish and avifauna), forming complex communities that depend on regular tidal inundation. More than three million shorebirds migrating between the Arctic and sites in Asia and Oceania stop over on the flats each year. However, the low cost of developing coastal lands and the scarcity of land elsewhere also make the tidal flats attractive to developers. “The flats in some areas are up to 20 km wide; they're reclaimed for alternative land uses across the entire Yellow Sea coastline”, explains conservation biologist Nick Murray (University of New South Wales, Sydney, Australia). “Unconstrained development is resulting in a hard wall of reclaimed land along the Chinese coastline that is expected to be part of an 1800-km-long urban corridor by 2030.”

Figure 1.

China's wall-to-wall coastal development is threatening migratory shorebirds.

In a study published this year (Austral Ecol 2015; doi:10.1111/aec.12211), Murray and fellow researchers Richard Fuller (University of Queens-land, Brisbane) and Ma Zhijun (Fudan University, Shanghai) concluded that the Yellow Sea tidal flats are at a turning point. As well as the loss of area, evidence of an ecosystem under pressure includes declining commercial fisheries stocks, increased prevalence of hypoxic zones, more jellyfish and harmful algal blooms, and dwindling numbers of migratory birds in Australia and Japan. While the problem is increasingly recognized by governments, a comprehensive development plan incorporating ecosystem conservation remains elusive. Tidal flats are frequently reclaimed for aquaculture development, which is often just the first step to permanent loss. “Agriculture often follows, with harder structures like urban development and ports a frequent next step”, warns Murray.

Satellite imagery indicates that while tidal flats have disappeared rapidly in China and South Korea, they have held their own and even increased in North Korea (Front Ecol Environ 2014; doi:10.1890/130260). “It may provide somewhere for migratory birds to continue their migration”, says Murray, “but it's still concerning because it seems to be due to increased sediment in rivers from North Korea clearing its forests.”

Biomass could generate carbon-negative power

Robin Meadows

UC Berkeley graduate student Daniel Sanchez knew it was a good idea to see how carbon capture would affect atmospheric emissions from biomass power plants, but he had no idea how good. Projecting a likely future electricity system in western North America with plenty of wind and solar power, Sanchez found that adding biomass with carbon capture into the mix could cut carbon emissions from power 145% from 1990 levels. “I was surprised”, he says. “I thought the amount of biomass was too small to allow for stringent carbon reduction.”

Sustainable bioenergy can be carbon neutral, reducing emissions by 100%. “Plants take carbon out of the atmosphere and burning biomass returns it”, explains Sanchez, who reported his findings in Nature Climate Change in February (2015; doi:10.1038/nclimate2488). But by using carbon capture and sequestration, biomass power becomes carbon negative, taking more from the air than it ends up emitting. Another surprise was that while biomass supplied just 10% of electricity demand in Sanchez's projection, the carbon savings were so high that they might offset fossil-fuel-based carbon emissions from the transportation sector.

These findings arose from fine-grained analyses of biomass supplies and electricity production. Sanchez mapped biomass, focusing on wastes and residues – including corn stover and wheat straw – rather than on land-hungry crops dedicated to biomass such as pulpwood and switch-grass. He also used a model to predict the power system's evolution through 2050. “It takes a snapshot of the existing system and projects it forward using mandates like increasing renewables and reducing carbon”, he says. California is on track to obtain one-third of its electricity from renewables by 2020, a proportion that Governor Jerry Brown wants to boost to one-half by 2030.

Sanchez hopes his work will spur development of carbon capture and sequestration systems. “We know how to separate out carbon and we know how to inject it into the ground”, he points out. What we don't know is how to scale up pilot projects into commercial ones – a problem he is tackling now, drawing on cost and performance data from current technology. Says Sanchez, “We need business models that allow learning-from-doing while staying afloat financially”.

Going roadless to save the Amazon

Janet Pelley

The western Amazon is home to extraordinary biodiversity, large expanses of intact tropical forest –and massive oil and gas reserves. A new study reveals that energy extraction concessions in the region have grown by 45 000 km2 since 2008, to cover a total of 733 414 km2 (Environ Res Lett 2015; doi:10.1088/1748-9326/10/2/024003). However, the deforestation that follows oil and gas roads could be minimized by roadless “offshore-inland” development, where drilling platforms are accessed not by roads but by helicopters or rivers, according to the study.

Earlier investigations have shown that access roads for fossil-fuel extraction trigger subsequent slash-and-burn agriculture, colonization, and overhunting in the Amazon, says lead author Matt Finer, an ecologist with the Amazon Conservation Association (Washington, DC). Given the oil and gas boom sweeping the five countries in the western Amazon, he and his team decided to comb through government data on hydrocarbon discoveries, map their extent, and classify whether they were developed and, if so, with or without access roads. The researchers found 11 major oil and gas projects with access roads, six projects without roads, and 35 undeveloped hydrocarbon discoveries. “In other words, oil and gas development in the Amazon is intensifying, so we really need to figure out the most sustainable way to proceed”, he says.

“Because the destruction comes from the secondary effects of opening roads through wilderness, the offshore-inland model of development can reduce these impacts”, explains study co-author Bruce Babbitt, former US Secretary of the Interior from 1993–2001 (Washington, DC). Peru's Camisea development in the Amazon, which supplies the entire country's gas demands, is a good example. There are no access roads and the forest has regrown over buried pipeline routes.

According to Bill Powers, senior engineer for charitable consulting firm E-Tech International (Santa Fe, NM), analysis reveals that if a proposed conventional project in northern Peru's Amazon were developed as an offshore-inland model, the project cost would drop slightly and substantial deforestation would be prevented. He acknowledges that Peru has led the way with a regulation requiring companies to provide detailed justifications when they can't use the offshore-inland model, but companies often find reasons to not use this approach. “We need unequivocal regulations that require best practices and spell out exactly what that means”, he concludes.

Shark-diving tourism: conservation boon or bane?

Virginia Gewin

Don't feed the bears. Or squirrels. Or deer. It's not uncommon to see these signs in a national park. But in the sea, a rapidly growing tourism industry based around diving to view sharks is largely built on luring these top predators with food.

The first meta-analysis of published shark-diving tourism studies finds that the industry could offer conservation potential for at least a handful of species if done in a precautionary, responsible manner (Biol Conserv 2015; doi:10.1016/j.biocon.2015.02.007). In addition to synthesizing the findings of 47 papers and creating new metrics to assess tourism operators and safety, the authors define 50 research questions that need to be answered to craft best practices for the industry: chief among them, the impacts that this tourist activity has on shark behavior.

Shark conservationists have cautiously embraced the notion that the nearly 400 diving operations that have developed in 85 countries during the past 15 years could make sharks more valuable alive than dead. Unfortunately, the industry has no standardized code of conduct. “Shark-diving tourism is like the ‘Wild West’ of wildlife tourism activities”, explains study lead author Austin Gallagher, an ecologist at the University of Miami (Coral Gables, FL). And it's the cowboys, Gallagher explains, that threaten not only the industry but also efforts to improve the reputation of these predators.

Figure 2.

A tourist hand-feeding a great hammerhead shark (Sphyrna mokarran) while shark diving in the Bahamas.

What rules do exist vary regionally. In Hawaii, for example, luring sharks with food is prohibited in state and federal waters. “In my experience, shark tourism companies generally don't follow the rules, and that creates controversy”, explains Mike Tosatto, a regional administrator with the National Marine Fisheries Service (Honolulu, HI). He adds that, like all ocean uses, the aim is for the industry to have a net positive impact – whether through conservation or education – and a code of conduct could help balance economics and conservation. Others agree; “The sustainability of the industry is only as strong as its weakest operator”, concurs Rick MacPherson, a senior advisor to the Pew Charitable Trusts (San Francisco, CA). “Shark-diving tourism operations need to be held accountable for what they're doing, and we need good science to assist efforts to establish best practices”, says Gallagher.

Crabs of future past

Pete Mooreside

Arguably the most iconic species of the Chesapeake Bay – one of North America's largest estuaries – is the blue crab (Callinectes sapidus). A Chesapeake Bay Stock Assessment Committee report (http://bit.ly/1E13Z0f) estimated that almost 300 million of these crustaceans inhabited the region in 2013; during that same year, Bay-wide combined commercial and recreational landings for blue crabs totaled over 18 million kilograms. This fishery, currently the country's largest for crabs and the Bay's most economically valuable overall, is strongly regulated, in part because of the species' notoriously variable year-to-year abundance. So how might today's crab populations be different from those in the more distant past?

Archaeologist Torben Rick (Smithsonian Institution, Washington, DC) and colleagues from other specialties – including blue crab biologists – recently joined forces to shed light on the ancestral crabs of the Chesapeake. “A near absence of research on the archaeology and historical ecology of the blue crab fishery inspired our work”, says Rick. To remedy this, the team conducted a three-part study: scouring museum collections for identifiable C sapidus remains from Native American, Colonial-era, and later sites; testing the susceptibility of modern crab parts to conditions that would presumably affect their successful preservation over time; and developing a quantitative method for estimating the size of historical crabs based on fragmentary archeological specimens (J Archaeol Sci 2015; doi:10.1016/j.jas.2014.12.016).

Figure 3.

Colonial-era crab claw fragments from a site near St Mary's City, MD.

The researchers discovered blue crab remains at 93 archaeological sites – dating between 3200 years ago and 1850 CE – along the Virginia and Maryland coastlines. By identifying up to 15 independent characteristics for more than 600 ancient claw fragments obtained from those sites, the team was able to extrapolate the crabs' likely carapace widths. On average, the old crabs were consistently larger than present-day individuals sampled from the Bay. Although Rick is quick to point to several caveats to this finding, he notes that the observed decrease in body size “probably relates to pressures from the modern-day blue crab fishery. This is important because it suggests to managers that the intensive fishery is having an influence on crab populations and sizes”.

Lyme disease on the wing in California

Adrian Burton

New research suggests that birds could be involved in the spread of Lyme disease in the western US (PLoS ONE 2015; doi:10.1371/journal.pone.0118146). Lyme disease, caused by a form of the bacterium Borrelia burgdorferi, is spread to humans by infected ticks, and manifests initially as a reddish rash, fever, fatigue, chills, joint pain, and sometimes neurological complications, often months after initial infection. In northwestern California, where the research was performed, the culprit is the western black-legged tick (Ixodes pacificus). Although it infests many vertebrate species, the dusky-footed woodrat (Neotoma fuscipes) and the western gray squirrel (Sciurus griseus) are widely regarded as the primary reservoirs of the disease-carrying bacterium in the region. However, epidemiologists may now want to pay more attention to birds.

Using mist nets, researchers captured 623 birds belonging to 53 species in four types of habitat: dense oak woodland, grassland, oak woodland, and chaparral. I pacificus was found on 100 birds, of which blood analyses showed 57 to be infected with some form (ie Lyme disease- and non-disease-causing) of the B burgdorferi complex. “Among these we found 10 species carrying [disease-causing] B burgdorferi”, explains principal investigator Robert Lane (University of California, Berkeley, CA). “We also collected the first evidence of birds [14 species] carrying the related bacterium Borrelia bissettii.” This bacterium causes a Lyme-disease-like illness in central and southern Europe, and occasionally infects people in northwestern California.

Birds associated with dense oak woodlands and grasslands were more likely to carry ticks, while those inhabiting chaparral were the least likely. “In California, chaparral is often removed to reduce fire risk”, explains lead author Erica Newman, also at Berkeley. “Replacing chaparral with non-native grasslands and suburban lawns might increase the number of infected birds; given how much chaparral is being converted, we may be unintentionally increasing the risk of Lyme disease for Californians.” Most of the infected birds were passerines, including the dark-eyed junco (Junco hyemalis), American robin (Turdus migratorius), and golden-crowned sparrow (Zonotrichia atricapilla). “We worked in natural habitats”, says Newman, “but several of the species we found carrying Borrelia are known to thrive in California's suburbs”.

“Birds are better equipped to spread Lyme disease over large distances, and more quickly than small mammalian hosts”, comments Lourdes Lledó (Professor of Microbiology, University of Alcalá de Henares, Spain). “We need to see whether other bird species in other parts of the world, where there are other tick species, might also spread the disease.”

Home batteries store solar power

Mike Faden

As more homes install solar panels, suppliers are starting to offer batteries that let homeowners store some of the energy they produce, further reducing their reliance on the electricity grid. The trend is part of a broader uptake of batteries for storing energy generated from renewable sources, such as solar, that produce electricity only part of the time. In the US, installations of energy-storage systems are expected to leap to 220 megawatts (MW) in 2015 –more than double the combined total installed during the previous 2 years, according to GTM Research (Boston, MA). To date, most of those systems have been acquired by utilities and businesses; only about 1% of last year's total capacity was purchased by homeowners. Yet GTM expects residential deployments to grow rapidly to more than 150 MW, representing 20% of total new capacity, by 2019.

For homeowners, these batteries offer protection against power outages and could cut electricity costs. “Solar coupled with storage can reduce the kilowatt-hours sold by utilities”, says Ravi Manghani, senior analyst at GTM Research. However, he emphasizes that battery storage is still too expensive for all but a handful of customers to go completely off-grid – at least for the next decade.

Still, energy-storage costs are falling, especially for lithium-ion batteries and other relatively new battery types that are smaller, lighter, and longer-lasting than older lead-acid batteries. “We've seen a roughly 50% cost reduction in lithium-ion batteries since 2011, made possible by scaling up manufacturing capabilities for electric vehicles”, Manghani continues.

Elon Musk, CEO of electric car maker Tesla Motors, recently revealed his company's plans to introduce home batteries. Tesla is currently building a “Gigafactory” in Nevada to produce lithium-ion batteries in collaboration with Japan's Panasonic. If the company's intentions come to fruition, Tesla has promised that the Gigafactory will greatly expand global battery production and reduce battery costs through economies of scale.

Several solar providers are planning to offer batteries in combination with solar panels. SolarCity – a San Mateo, CA-based solar power provider in which Musk is the largest individual shareholder – is running a home battery pilot program, and has said that within 10 years every solar system it sells will come with battery storage. The company is currently using its modestly sized 10-kilowatt-hour pilot systems as backup protection for power outages. Other companies moving to offer battery storage include SunEdison (St Peters, MO), which recently acquired a battery startup, and SunPower (San Jose, CA).

Italian designers create human-to-tree burial pod

Jen Fela

Two Italian designers, Anna Citelli and Raoul Bretzel, have created a unique burial method for humans called Capsula Mundi, where the body of the deceased is placed in the fetal position within a large, egg-shaped pod that is then buried underground. As the body decomposes, the pod –made from biodegradable, plant-derived plastic – functions as a source of nutrients that feeds a tree planted directly above it. While living, a person can choose the type of tree to be planted, and after death, family members and friends can care for the tree. Thus, a grave would be marked by a living, growing tree rather than a cold headstone, eventually creating what the designers envision as “memory forests” that loved ones can visit in place of traditional cemeteries.

Despite the interest and excitement generated by the concept, this burial practice is illegal in Italy and most parts of the US. Joe Sehee, Founder of the Green Burial Council (Ojai, CA), says, “Unfortunately, most cemeteries in North America require the use of burial vaults made from concrete, which would prevent the Capsula Mundi concept from working”. He also emphasizes that there are elements other than just a well-designed burial capsule that are required to perpetuate green burials: “What's needed are more burial grounds that allow for the use of living/ecologically functional markers, as well as those that ensure that burial never degrades a local ecosystem and (where possible) facilitates ecological restoration”.

Figure 4.

The biodegradable burial pod, which resembles a large seed, will nourish the living tree planted above it.

The Capsula Mundi designers have created an association (Associazione Capsula Mundi) to try to change Italian legislation so that their project can become a reality, and Sehee affirms that public support for these types of projects is growing. “While the use of embalming chemicals, metal caskets, and concrete burial vaults once appealed to a culture infatuated with sanitation, to growing numbers of people today these practices and products are regarded as anachronistic, toxic, and/or energy-intensive. Conversely, I think people are finding a great deal of solace in knowing that one's last act can play a role in the healing of the planet.”

Urban development drives rapid evolutionary change

Lindsay Deel

Evolutionary processes in urban environments might be accelerating more quickly, due in part to human activities and changes in natural habitats. A new paper (Trends Ecol Evol 2015; doi:10.1016/j.tree.2014.11.007) highlights particular changes in urban organisms that have been observed during the past decade – including tamer and bolder birds, larger spiders, and weeds that disperse their seeds differently than their rural counterparts. There is even evidence that songbirds are changing their calls in an effort to keep urban background noise from masking their acoustic signals. “Humans selectively determine which species can live in cities and cause organisms to undergo rapid evolutionary change”, says study author Marina Alberti (University of Washington, Seattle, WA).

Humans alter urban landscapes in several ways – for example by converting and fragmenting natural vegetation; introducing noise, light, and chemical pollution; and altering microclimate and resource availability –that directly influence other city-dwelling species. According to Alberti, these changes “affect ecosystem function, biodiversity, nutrient cycling, seed dispersal, water and air purification, food production, human health, and social and cultural values”. Urbanization also increases the pace of life and changes the dynamics of social interactions among people, with important implications for the exploitation of natural resources and acceleration of what Alberti calls “eco-evolutionary feedback”.

Figure 5.

City songbirds are changing their tunes.

The pace of growth in cities has the potential to tip the scales of evolutionary change, especially as the functional links between cities extend far beyond their borders. Alberti suggests that such distant connectedness or “telecoupling” is changing the way we think about urban ecosystems. Cities represent a highly interconnected hybrid system of human and ecological interactions. “It is their hybrid nature that makes them unstable but also capable of innovating”, she explains. These interactions prompt the question of whether the “emergence and rapid development of cities across the globe could change the course of the evolution of life on Earth”.

Members of Alberti's Urban Ecology Research Lab are tackling this question and others by developing empirical studies in the Seattle metropolitan area and the Puget Sound region and by mapping insects, birds, and microbial communities in urban parks. They are also investigating different ways that humans could alter destructive patterns and drive evolutionary changes toward a more resilient and sustainable future. “Most importantly”, Alberti continues, “we're creating a network of scientists working on eco-evolutionary feedback to start cross-site collaborations and research studies”.

Transforming dairy farm waste into seafood

Katherine Blackwood

Housefly (Musca domestica) maggots, or larvae, may be the missing link in a process that would convert dairy cow waste into farm-raised fish on a large scale. An interdisciplinary Cornell University research team is investigating the feasibility of industrial-scale production of larvae meal as feed for aquaculture operations.

The rapidly expanding aquaculture sector faces dual pressures: the rising costs of preferred protein sources used in feed (currently fish, soybean, and meat meals), and the demands of a growing human population. In fact, the FAO estimates that meat production will have to ramp up 70% by 2050 to feed humanity. Hand-in-hand with this projected increase, the environmental damage associated with livestock waste and its disposal will likely intensify in coming decades.

This is where the Cornell team's larvae squirm onto the stage, ideally solving two major sustainability problems in food production: reducing the burden of livestock waste on the environment while alleviating the feed industry's massive demand for soybeans and fish. The team, led by Vimal Selvaraj, professor of animal science at Cornell (Ithaca, NY), is “approaching this problem a little differently than most biology labs, where the study of a process becomes the primary theme. Our objective is not to make a new discovery in science; it is to take a phenomenon that occurs every day in nature and see whether we can take a more intensive approach, examining how to maximize our yield without escalating the price”.

Although nearly 50 years have passed since researchers began investigating the production of larval biomass as animal feed, the practice is still rare. Obstacles to large-scale deployment include limited data on nutrition and bioconversion, concerns over disease transmission, and prohibitive costs. However, Selvaraj notes that nutritional analyses find housefly larvae to be “absolutely on par with fish-meal in terms of amino-acid levels”, and that pathogen transmission is not a concern, given that larvae are harvested and processed after emptying their gut in preparation for pupation. The team's market assessment and business plan are in a forthcoming report.

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