Constantine Alexander's blog

US Military vets to help rebuild northern California fisheries

NOAA partners with California to offer training and employment in habitat restoration; space still available for veterans to apply

Veterans will get a chance to train and work on habitat restoration and fisheries monitoring through a project funded by NOAA and administered in partnership with the California Conservation Corps and California’s Department of Fish and Game.

During the yearlong program of paid training and hands-on experience, veterans will spend part of the time on habitat restoration and will also receive training and experience in firefighting and reducing fire hazards.

“This is a win-win for everyone,” said Eric Schwaab, NOAA’s assistant administrator for fisheries. “Military veterans have tremendous skills to offer, and by helping to restore fish habitats they will be supporting the important role of commercial and recreational fishing in the economy. Restoration jobs pay dividends twice, first because they put people to work immediately, and then because restoration benefits our fisheries, tourism, and coastal communities for years to come.”

Veterans will start the program by taking courses in how to collect data and evaluate the effectiveness of coastal and marine habitat restoration. By mid- to late October, they will begin monitoring several river restoration sites in Humboldt, Del Norte, and Mendocino counties that were designed to increase spawning and rearing habitat for populations of endangered coho salmon in accordance with the recovery plan developed under the Endangered Species Act. The restored habitat should also help boost populations of Chinook and steelhead trout as well as improve environmental quality generally.

"We're excited about the new veterans’ fisheries crew getting underway,” said David Muraki, director of the California Conservation Corps, a state agency that provides employment and training for youth ages 18 to 25. “We've had success with other veterans’ crews that focused on firefighting and energy technology. This will be our first foray into using military veterans for habitat restoration.”

"Our veterans have earned our thanks and our support," said California Department of Fish and Game Director Charlton H. Bonham. "California's ocean and river resources are part of our national heritage, and we are privileged to be able to offer some of these veterans jobs in restoration and conservation."

By providing meaningful training and work experiences in conservation, the project aligns with several Obama Administration initiatives, including the Veterans Job Corps Initiative and America’s Great Outdoors, which calls for the development of a 21st Century Conservation Service Corps to help protect, restore, and enhance the outdoor environment. It is also part of NOAA’s effort to implement the National Ocean Policy, which calls for establishing a coastal conservation corps network. The program also works toward the same goals as Joining Forces, a comprehensive national initiative of First Lady Michelle Obama and Dr. Jill Biden to mobilize all sectors of society to give our service members and their families the opportunities and
support they have earned.

Veterans interested in joining the fisheries crew should contact the California Conservation Corps’ Tina Ratcliff at 916-341-3123 before training begins on Monday, September 17. NOAA’s mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources.  

 

 

Conservation International Celebrates 'Game-changing' pledge of co-operation between U.S. and Kiribati for ocean protection at Pacific Island Forum

Phoenix Islands Protected Area (PIPA). © Conservation International/Cat Holloway

With an area of 800,000 square kilometers, the Phoenix Ocean Arc will be the largest whole archipelago, trans-boundary conservation partnership.

In the final day of the 43rd Pacific Island Forum, Kiribati President His Excellency Anote Tong welcomed Secretary of State Hillary Clinton’s unprecedented commitment, on behalf of the United States, to ocean conservation in the Pacific Region. Deepening its relationship between Kiribati’s Phoenix Islands Protected Area (PIPA) and the Pacific Remote Islands Marine National Monument (PRIMNM), a huge area of the Pacific Ocean managed by the United States, the stretch of ocean has been dubbed the Phoenix Ocean Arc.

Phoenix Islands Protected Area (PIPA). © Conservation International/Cat Holloway

“The Phoenix Ocean Arc announcement is a game changer for the oceans,” said Conservation International’s Pacific Marine Director Sue Taei. “It will provide the basis for co-operation between one of the world’s largest economies and one of the smallest economies, which meet on the ocean as equals in their commitment and stewardship. They are both large ocean states working together forging a critical way forward to conserve the world’s blue economy.”

“It will deliver both individual and collective aspirations for conservation and will focus on both natural and cultural heritage conservation,” said Tong, who is also a board member with Conservation International. “The protection of the islands and ocean of the Phoenix Ocean Arc is a common challenge and this agreement reflects a shared vision, a compelling impetus for co-operation that crosses huge tracks of ocean, politics and heritage.”

Secretary Clinton told the gathering at the forum, “our countries are bound by shared interest, and more importantly, shared values, a shared history, and shared goals for our future. So the United States is already invested in the Pacific. Indeed, we are increasing our investments and we will be here with you for the long haul.”

Secretary Clinton also voiced support by the U.S. for the Pacific Oceanscape initiative envisioned by President Tong and endorsed by Pacific Islands Forum Leaders in 2010, and welcomed opportunities to identify ways of protecting and managing PRIMNM and PIPA, including both the Phoenix and Line Islands of Kiribati. 

Co-operation between USA and Kiribati is long standing with the Treaty of Friendship (1979), a Shipriders agreement (2008) and the collaboration on protected areas under a sister-site agreement between PIPA and Papahānaumokuākea Marine National Monument. The archipelago spans eight islands governed by Kiribati and two by the U.S. (Howland and Baker).

In addition to sharing a remote archipelago, both sites:

• Are exceptionally large, remote marine protected areas, managed to protect species of concern and their habitats, entire ecosystems, including both shallow and deep water habitats, and they include vast geographic areas of the central Pacific Ocean.
• Have globally important terrestrial island habitat and species, including threatened seabird and turtle populations, and share similar issues and problems with respect to invasive species management.
• Share a mandate for strong protection and conservation of the extraordinary, and still nearly pristine marine environments, dominated by large predatory fish such as sharks.
• Are largely unaffected by the threats typically facing coral reef systems across the globe such as land-based sources of pollution, but are challenged by overwhelming global threats like climate change.
• Are highly regulated sites where access is limited, and surveillance and enforcement is a challenge.
• Have significant management costs and challenges, due to the remote nature and size of the sites.
• Serve as global sentinel research sites, providing early warning and a comparative baseline to develop an better understanding of how natural systems react to changing climatic conditions and external influences, because compounding factors from human disturbance and habitation are largely absent.
• Have a shared and rich history of American and Micronesian heritage.

Regarding the U.S Asia Pacific strategic engagement initiative launched in July, Secretary Clinton also noted the U.S plans for programs that total than $32 million which will address priorities that the Pacific Island Nations have identified. Secretary Clinton noted that “one of these is sustainable economic development that protects biodiversity.”

The Phoenix Ocean Arc is the first of the Pacific Oceanscape’s ocean arcs, designed to protect, large ocean areas, inclusive of island, coastal, open ocean, and deep-sea habitats. Marine and terrestrial protected areas remain the single most commonsense tool and biological insurance policy for Pacific Islands people to build resilience and capacity to environmental and climate change. The Pacific Ocean Arc concept fosters protected area design and investment that focuses on the archipelagic nature of the central Pacific and that includes the full range of approaches to protected areas, from village-based approaches to international collaboration for open ocean protection.

At this year’s Pacific Islands Leaders Forum, the governments of New Caledonia and the Cook Islands both announced major contributions to the Pacific Oceanscape, adding to those made previously by Kiribati and Tokelau.

Building upon a strong foundation of science, partnership and field demonstration, Conservation International empowers societies to responsibly and sustainably care for nature, our global biodiversity, for the long term well-being of people. Founded in 1987, CI has headquarters in the Washington, DC area, and nearly 900 employees working in more than 30 countries on four continents, plus 1,000+ partners around the world. 

 

 

Bacteria on marine sponges can develop capacity to move and inhibit biofilm formation

Dr. Russell Hill, Director of the Institute of Marine and Environmental Technology in Baltimore, Md. . Courtesy University of Maryland Center for Environmental Science/Cheryl Nemazie

A new study shows that when enough bacteria get together in one place, they can make a collective decision to grow an appendage and swim away. This type of behavior has been seen for the first time in marine sponges, and could lead to an understanding of how to break up harmful bacterial biofilms, such as plaque on teeth or those found on internal medical devices like artificial heart valves.

Bacteria have ways of communicating with each other, and scientists have now identified a new signaling system that, when there is a critical mass of bacteria present, causes the bacteria to produce an appendage known as a flagellum that moves like a corkscrew and gives them the ability to swim away, inhibiting the formation of biofilm.

"Anything we can discover about this bacterial communication could be really important in understanding how bacteria become pathogenic in humans or how they form film on teeth or internal medical devices," said study co-author Dr. Russell Hill, Director of the Institute of Marine and Environmental Technology in Baltimore, Maryland. "Understanding that process may help in the future for controlling biofilms."

It is estimated that pound by pound there are more bacteria on the Earth than all other life forms combined. They are simple organisms that consist of one cell and can only be seen through a microscope. However, bacteria have evolved ways to gather into densely populated and slimy communities called "biofilms," which attach to hard surfaces. They also know how to talk to each other, and can make group decisions about how to behave, called 'quorum sensing.'

Marine sponges in particular harbor complex and diverse bacterial communities, in some cases as much as 30-40% of the sponge's biomass. This high density of bacteria is an ideal place to study signaling, or how bacteria talk to each other using small chemical molecules. Just like in a business meeting, once enough bacteria gather in one place—or a quorum is met—a decision about their collective behavior can be made. This 'quorum sensing' is responsible for a number of cellular processes, including triggering molecular mechanisms that can make the surface of the ocean light up at night and the gathering of bacteria that causes plaque on teeth, otherwise known as biofilm.

The bacteria that colonize and are dependent on these marine sponges use quorum sensing to activate their locomotion when their population becomes dense, naturally limiting the amount of biofilm they form.

"This precise calibration of the bacterial interactions within the sponge may have evolved to help maintain a healthy, well-distributed symbiotic population," said study coauthor Clay Fuqua of Indiana University. "Similar mechanisms may be at play in other complex microbial communities within hosts such as those within human intestines and in symbiotic plants

This new study by scientists from the University of Maryland Center for Environmental Science's Institute of Marine and Environmental Technology, Indiana University, and University of Colorado Denver's School of Medicine, is published in the September 2012 issue of Molecular Microbiology.

Contact: Amy Pelsinsky
apelsinsky@umces.edu
410-313-8808
University of Maryland Center for Environmental Science

 

 

Albatross 'dynamic soaring' achieved by repeated curve-altitude oscillation

Albatrosses leverage the energy of the wind to fly with essentially no mechanical cost to themselves, very rarely flapping their wings, and new work published Sep. 5 in the open access journal PLOS ONE offers insight into how exactly they accomplish this feat.

The researchers, led by Gottfried Sachs of the Technische Universitaet Muenchen and Francesco Bonadonna of the French National Centre for Scientific Research (CNRS), used advanced GPS tracking to determine that the energy gain during the albatross's "dynamic soaring" comes from a repeated oscillation consisting of a combined curve-altitude flight maneuver, with optimal adjustment for the wind. The results may provide inspiration for robotic aircraft that utilize the flight technique of albatrosses for engineless propulsion, the authors write.

Citation: Sachs G, Traugott J, Nesterova AP, Dell'Omo G, Ku¨mmeth F, et al. (2012) Flying at No Mechanical Energy Cost: Disclosing the Secret of Wandering Albatrosses. PLOS ONE 7(9): e41449. doi:10.1371/journal.pone.0041449

Contact: Yael Franco
yfranco@plos.org
415-568-3169
Public Library of Science

 

 

Picky penguins: Does mate choice depend on genes that help resist disease?

Magellanic penguins. Photo courtesy of J. L. Bouzat

Magellanic penguins have a high level of variation in genes associated with the ability to fight infectious disease, but a recent study found that the mechanism the penguins use to ensure that diversity is far from black and white.

Found exclusively south of the equator in South America, Magellanic penguins assemble in large nesting colonies along the coasts of Argentina, Chile, and the Falkland Islands. They typically mate for life, producing clutches of two eggs that are cared for by both parents. While individual colonies can number in the millions of birds, the species as a whole appears to be in decline, and is therefore classified as "Near Vulnerable" by the IUCN Red List.

A recent study published via Advance Access (doi: 10.1093/jhered/ess054) in the Journal of Heredity tested whether the significant diversity in the Major Histocompatibility Complex (MHC) genome region observed in these birds is attributable to mate choice or genetic selection based on disease exposure.

The study first confirmed that MHC diversity is high in these birds compared to other closely-related penguin species. Gabrielle Knafler, a graduate student at Bowling Green University and the first author of the study, explained, "By looking at the MHC genotypes of 50 breeding pairs of Magellanic penguins, we found considerable levels of genetic variation, detecting a significantly greater number of MHC variants or alleles than those reported for Galapagos penguins and Humboldt penguins." Forty-five alleles were found at the gene locus for the Magellanic penguins, sampled from a wild population in southern Patagonia, compared to 3 for Galapagos penguins and 7 for captive Humboldt penguins.

The authors of this study then investigated two possible mechanisms for maintaining the high MHC diversity in the Magellanic penguins: balancing selection, in which heterozygous individuals are better adapted to combat a wide range of diseases and are therefore more likely to survive to pass on their genes, and disassortative mating, or preferentially choosing a mate with a different MHC genotype.

How might a penguin know that a potential mate has different MHC genes? Smell could tell. Dr. Juan L. Bouzat of Bowling Green University, the lead scientist on the study, said, "In some species in which disassortative mating has been detected, individuals discriminate among potential mates by MHC type on the basis of olfactory cues."

To test the mechanism for maintaining MHC diversity, the authors studied the genetic variation of 50 breeding pairs of penguins. They examined whether MHC diversity was greater between breeding pairs as compared to random mating, and determined whether MHC genotype was correlated with measures of reproductive fitness, such as number of eggs hatched and number of chicks fledged.

Surprisingly, they found no direct evidence for disassortative mating based on the genotypes of the breeding pairs. Incidence of shared alleles between males and females in breeding pairs was not significantly different from what would be expected by chance.

But heterozygosity was found to be associated with increased fitness of adults, as heterozygous females hatched significantly more eggs and fledged significantly more chicks than homozygous females (in fact, none of the homozygous females that hatched eggs actually fledged any chicks). This finding suggests that a mechanism for balancing selection is at work in maintaining MHC diversity, even if it is not promoted by disassortative mating.

Other evidence for balancing selection was also found, including a gene phylogeny for MHC alleles from Magellanic, Humboldt, and Galapagos penguins. This analysis, akin to developing a "family tree" for genes, found that MHC alleles did not group together by species, suggesting that balancing selection has maintained different alleles even as species evolved over millions of years.

"There are likely other mechanisms at work as well," said Bouzat. "Spatial and temporal patterns in exposure to different pathogens may shape which alleles are favored at different times," changing selection pressures on the MHC genes. "The direct association of MHC genes with mechanisms of disease resistance suggests that the maintenance of MHC diversity could be driven by periodic selection due to different pathogens, similar to epidemics in humans."

Contact: Nancy Steinberg
nsteinberg@charter.net
541-574-0908
Journal of Heredity

 

 

Wildlife Conservation Society releases list of Asian species at the conservation crossroads

This is an extremely rare still of a kouprey, from the only known footage of this extinct species, once native to Southeast Asia.

Will the tiger go the way of the passenger pigeon or be saved from extinction like the American bison? The Wildlife Conservation Society (WCS) today released a list of Asian species that are at a conservation crossroads calling for governments to take immediate action with The Three R's Approach: Recognition, Responsibility, Recovery. The list includes: the tiger, orangutans, Mekong giant catfish, Asian rhinos, Asian giant river turtles, and Asian vultures. The announcement was made at the IUCN's World Conservation Congress convening in Jeju, South Korea through Sept. 13.

WCS says that each species can follow the path of the passenger pigeon, which went extinct in the early 20th century, or the bison, which was saved using the 'three R's' approach. In the case of the bison, which was decimated by overhunting, its plight was recognized, responsibility was taken, and recovery resulted with more than 30,000 wild individuals in existence today. WCS was directly involved in saving the bison by breeding animals in the Bronx Zoo and working with partners to reintroduce them into protected areas in the early 1900s.

"As in the United States, it will not be the species themselves deciding which fork to take, but actions of humans using the three R's: recognition, responsibility and recovery – recognizing the problem, taking responsibility for solving it, and putting species back on the path to recovery," said WCS President and CEO Dr. Cristián Samper.

Though each Asian species on the list faces daunting challenges from a variety of factors including habitat loss, and illegal hunting and trade, WCS believes that Asian governments have the ability – and financial means – to turn the tide on extinction.

The tiger is an example of a species that could be going the way of the bison, at least in some locations, according to WCS. India took responsibility for the tiger when it announced Project Tiger in 1972. By doing so it sent a clear message that the fate of the wild tiger was in its hands and India alone would be held accountable for their future. This almost unprecedented commitment led to one of the few examples of a major Asian species undertaking a sustained recovery. Today, while problems and challenges remain, India remains committed to ensuring that tigers are conserved effectively within its boundaries. Similarly, in the Western Forest Complex in Thailand, the Thai Government is taking responsibility for protecting its tigers by taking bold steps to overcome the poaching pressures.

Other species, such as the orangutan, face a bleaker future with widespread conversion of its habitat into palm oil plantations that have decimated wild populations. Asian rhinos and giant river turtles face relentless poaching pressure for the illegal wildlife trade, while Asian vultures have been nearly wiped out due to poisoning. Mekong giant catfish numbers have plummeted due to overfishing

WCS warns that time is running out for Asia's wildlife, noting that two large mammal species – the kouprey, a type of wild cattle once found in Southeast Asia, and a Chinese freshwater dolphin species called a baiji – have gone extinct.

The Wildlife Conservation Society saves wildlife and wild places worldwide. We do so through science, global conservation, education and the management of the world's largest system of urban wildlife parks, led by the flagship Bronx Zoo. Together these activities change attitudes towards nature and help people imagine wildlife and humans living in harmony. WCS is committed to this mission because it is essential to the integrity of life on Earth. 

Contact: Stephen Sautner
ssautner@wcs.org
718-220-3682
Wildlife Conservation Society

 

 

Loss of tropical forests reduces rain

Deforestation can have a significant effect on tropical rainfall, new research confirms. The findings have potentially devastating impacts for people living in and near the Amazon and Congo forests.

A team from the University of Leeds and the NERC Centre for Ecology & Hydrology found that for the majority of the Earth's tropical land surface, air passing over extensive forests produces at least twice as much rain as air passing over little vegetation. In some cases these forests increased rainfall thousands of kilometres away.

By combining observational data with predictions of future deforestation, the researchers estimate that destruction of tropical forests would reduce rain across the Amazon basin by up to a fifth (21 per cent) in the dry season by 2050. The study is published today in Nature.

Lead author Dr Dominick Spracklen from the School of Earth and Environment at the University of Leeds said: "We were surprised to find that this effect occurs strongly across more than half of the tropics. We found that the Amazon and Congo forests maintain rainfall over the periphery of the forest basins - regions where large numbers of people live and rely on rainfall for their livelihoods.

"Our study implies that deforestation of the Amazon and Congo forests could have catastrophic consequences for the people living thousands of kilometres away in surrounding countries."

Scientists have debated whether vegetation increases rainfall for hundreds of years. It is well established that plants put moisture back in the air through their leaves by a process known as evapotranspiration, but the quantity and geographical reach of rainfall generated by large forests has – until now – been unclear. While there is plenty of anecdotal evidence that forests significantly increase rainfall, until now there has been a lack of observational evidence.

The team used newly available NASA satellite observations of rainfall and vegetation, along with a model which predicts atmospheric wind flow patterns, to explore the impact of the Earth's tropical forests.

"We looked at what had been happening to the air over previous days – where it came from and how much forest it had travelled over," Dr Spracklen said.

To understand the relationship in detail, they investigated the journey of air masses arriving over different parts of the forest, to see the cumulative amount of leaf cover the air had moved over during the previous ten days, not just the amount of vegetation it was over when it rained. This showed that the more vegetation the air had travelled over, the more moisture it carried and more rain was produced.

Dr Stephen Arnold from the University of Leeds, a co-author on the paper, said: "The observations show that to understand how forests impact rainfall, we need to account for how air has interacted with vegetation during its journey through the atmosphere often over thousands of kilometres. This has significant implications for how policy makers should consider the environmental impacts of deforestation, since its effects on rainfall patterns may be felt not only locally, but on a continental scale."

Dr Spracklen said the findings showed the importance of initiatives to protect tropical forests. "Brazil has recently made progress in slowing the historically high rates of deforestation across the Amazon and our study emphasises that this progress must be maintained if impacts on rainfall are to be avoided.

"The Amazon forest maintains rainfall over important agricultural regions of Southern Brazil, while preserving the forests of the Congo Basin increases rainfall in regions of Southern Africa where rainfed agriculture is important. Increased drought in these regions would have severe implications for their mostly subsistence farmers."

The study was funded by NERC.

Contact: Esther Harward
e.harward@leeds.ac.uk
44-113-343-4196
University of Leeds

 

 

New study examines how ocean energy impacts life in the deep sea

Results will help scientists understand what to expect under future climate change

This shows assorted invertebrates on the seafloor off of Central California (Tiburon Dive# 606; Lat= 37.4; Lon= -123.3; Depth= 1949.8 m). Courtesy of the Monterey Bay Aquarium Research Institute (MBARI) (c) 2003

A new study of deep-sea species across the globe aims to understand how natural gradients in food and temperature in the dark, frigid waters of the deep sea affect the snails, clams, and other creatures that live there.

Similar studies have been conducted for animals in the shallow oceans, but our understanding of the impact of food and temperature on life in the deep sea — the Earth's largest and most remote ecosystem — has been more limited.

The results will help scientists understand what to expect in the deep sea under future climate change, the researchers say. "Our findings indicate that the deep sea, once thought remote and buffered against climatic change, may function quite differently in the future," they write.

All living things need energy in the form of food, heat and light to survive, grow, and reproduce. But for life in the deep sea — defined as anything beyond 600 feet (200 m) — energy of any kind is in short supply. Descend more than a few hundred feet beneath the ocean surface, and you'll find a blue-black world of near-freezing temperatures, and little or no light.

Sea pen, sea cucumber, and brittle stars on the seafloor northwest of Monterey Bay, 1,700 meters below the sea surface. Courtesy of the Monterey Bay Aquarium Research Institute (MBARI) (c) 2005

Because so little of the sun's light penetrates the surface waters, there are no plants for animals to eat. Most deep-sea animals feed on tiny particles of dead and decaying organic matter drifting down from the sunlit waters above. It is estimated that less than 1% of the food at the surface reaches the ocean's watery depths.

The researchers wanted to know what this energy deprivation means for deep sea habitats across the globe, and for the animals that live there. "How much of the differences that we see across different groups of deep-sea animals in terms of growth, or lifespan, or the number of species, are related to differences in the temperature or amount of food where they occur?" said co-author Craig McClain of the National Evolutionary Synthesis Center in Durham, North Carolina.

To find out, the researchers compiled previously published data for hundreds of deep-sea species across the globe, ranging from crabs and snails to fish and tube worms. The data included parameters like metabolic rate, lifespan, growth, biomass, abundance, size and diversity.

The results suggest that the relative importance of the two basic forms of energy available in the deep sea — food and warmth — vary considerably, said co-author Michael Rex at the University of Massachusetts in Boston.

Temperature has the biggest impact on parameters at the individual level, such as metabolism and growth rate. For example, deep sea animals living in warmer waters tend to have faster metabolisms.

But for higher-level parameters such as abundance or species diversity, food is more important. Generally speaking, food-rich areas tend to have animals that are bigger, more abundant and more diverse.

The results add to the growing body of evidence that the deep sea isn't isolated from the effects of climate change, the researchers say.

"The oceans are getting warmer and they're producing less food," McClain said. Warmer water in the deep sea due to climate change could mean faster growth and metabolism for the animals that live there, but that could be bad news if the oceans produce less food to support them.

"The news is not good," Rex added. "Changes in temperature and food availability associated with climate change could cause widespread extinction in the deep ocean if environmental changes occur faster than deep-sea organisms can respond by shifting their ranges or adapting to new conditions."

The study was published online in the September 4, 2012 issue of Proceedings of the National Academy of Sciences.

Other authors of the study were Andrew Allen of Macquarie University in Australia, and Derek Tittensor of the United Nations Environment Programme World Conservation Monitoring Centre in the United Kingdom.

CITATION: McClain, C., A. Allen, et al. (2012). "The energetics of life on the deep sea floor." PNAS.

Contact: Robin Ann Smith
rsmith@nescent.org
919-668-4544
National Evolutionary Synthesis Center (NESCent)

The National Evolutionary Synthesis Center (NESCent) is a nonprofit science center dedicated to cross-disciplinary research in evolution. Funded by the National Science Foundation, NESCent is jointly operated by Duke University, The University of North Carolina at Chapel Hill, and North Carolina State University. 

 

 

Trout will become extinct in the Iberian Peninsula in less than 100 years

Climate change, pollution, the extraction of water for irrigation and overfishing all threaten the survival of the common trout. This fish is very sensitive to changes in its environment and, according to the Spanish study, its habitat will have reduced by half by the year 2040 and will have completely disappeared from Iberian rivers by 2100, so its population will become extinct.

Global warming is threatening the existence of many fish species, especially those in the salmonid family, which are sensitive to temperature changes as they require clear and fresh water to live. According to the calculations of a study carried out at the Complutense University of Madrid (UCM), the habitat of the common trout (Salmo trutta) in the Iberian Peninsula will have practically disappeared by the year 2100.

Ana Almodóvar is a researcher and the lead author of the study published in the 'Global Change Biology' journal. It deals with how variations in temperature affect trout population both now and in the future. "This fish has very narrow physiological margins in which it can live and is therefore a good indicator of the highest stretches of our rivers," as explained to SINC by the expert.

The scientists analysed the temperature records of Navarra between 1975 and 2007 and using a mathematical model they calculated the temperature of the region's rivers. "We saw a clear tendency of temperature increases, which was particularly marked around 1986," outlined Almodóvar. In addition, the team monitored the trout populations of 12 rivers in the Ebro basin and saw that an increase in temperature was associated with a decrease in trout populations.

The biologist points out that "measurements are exact and temperature records are for long periods of time." Therefore, thanks to the collected data, the scientists have been able to create their forecast of the state of the trout in the future.

"In the best of cases, which would involve just slight climate changes, the situation for the trout is disastrous," confirms Almodóvar. The study states that the temperature increases in Spanish rivers will cause the trout to lose half of its habitat by 2040 and become practically extinct by the year 2100.

According to the research team, these results can be extrapolated to other regions of the Iberian Peninsula and the Mediterranean, such as the Italian, Balkan and Anatolian Peninsulas. "The Mediterranean region is very vulnerable to climatic variations and to the decrease in water availability," she adds.

An unrecoverable loss

"It has always been thought that due to climate change trout populations in Southern European countries would be more affected than those in the North. But, a specific study was needed to confirm this notion," points out Almodóvar.

Trout in the Iberian Peninsula displays great genetic variability and it is considered a hot point of biodiversity in the whole continent for this species. The expert explains that "the Hispanic river basins are very ancient and acted as a refuge for Europe's fauna during the Pleistocene ice ages."

Scientists report that this variability is not only under threat by climate change but also because "over the years Spain's rivers have been repopulated with genetically different types of trout."

"There is much allochthonous gene contamination amongst the native population of these fish since over time eggs have been imported from fish farms instead of developing the specific and pure lineage of each basin," adds the researcher with much regret.

One of the greatest threats: fishing

The scientists confirm that due to pollution, the use of fresh water for irrigation and an increase in temperature, "the ecologic state of rivers is more and more precarious and nowadays there are only trouts at the river sources."

Furthermore, trout is a priority species in recreational fishing in Spain and represents a "very important" socioeconomic resource. Almodóvar outlines that there is more and more demand for trout fishing and studies have been warning of the problems of overfishing for years.

"A common characteristic of populations subject to recreational fishing is that there has been a decrease in the oldest specimens since they are captured for being the largest," concludes the expert.

Reference: Almodóvar, A.; Nicola, G.G.; Ayllón, D.; Elvira, B. "Global warming threatens the persistence of Mediterranean brown trout" Global Change Biology 18: 1549. DOI: 10.1111/j.1365-2486.2011.02608.x 2012

Contact: SINC Team
info@agenciasinc.es
FECYT - Spanish Foundation for Science and Technology

 

 

Ecosystems cope with stress more effectively the greater the biodiversity

Higher average temperatures and increasing salt concentrations are stress factors that many ecosystems face today in the wake of climate change. However, do all ecosystems react to stress in the same way and what impact does stress have on ecosystem services, such as biomass production? Botanists and ecologists from the universities of Zurich and Göttingen demonstrate that a high level of biodiversity aids stress resistance.

Higher number of species leads to greater stress resistance

The scientists studied a total of 64 species of single-celled microalgae from the SAG Culture Collection of Algae in Göttingen. These are at the bottom of the food chain and absorb environmentally harmful CO2 via photosynthesis. "The more species of microalgae there are in a system, the more robust the system is under moderate stress compared to those with fewer species," says first author Bastian Steudel, explaining one of the results. Systems with a higher number of species can thus keep their biomass production stable for longer than those with less biodiversity.

In all, the researchers studied six different intensities of two stress gradients. In the case of very high intensities, the positive effects of biodiversity decreased or ceased altogether. However, increasing stress in systems with few species had a considerably more negative impact than in those with high biodiversity levels. "The study shows that a high degree of biodiversity under stress is especially important to maintain biomass production," says Steudel's PhD supervisor Michael Kessler, summing up the significance of the research project.

Reference: Bastian Steudel, Andy Hector, Thomas Friedl, Christian Löfke, Maike Lorenz, Moritz Wesche, Michael Kessler. Biodiversity effects on ecosystem functioning change along environmental stress gradients. Ecology Letters. 4 September, 2012. doi: 10.1111/j.1461-0248.2012.01863.x

Contact: Dr. Bastian Steudel
bastiansteudel@aol.com
49-157-879-52830
University of Zurich