Constantine Alexander's Journal

Vultures foraging far and wide face a poisonous future

White-backed vulture. Credit: Steve Garvie

A first ever study of the range and habits of white-backed vultures across southern Africa shows that they often shun national parks, preferring to forage further afield on private farmland.

This behaviour and their tendency to scavenge in groups, means that vultures risk encountering dead cattle that have been administered veterinary drugs that are poisonous to them, or even poisoned carcasses intended to control other carnivores such as jackals.

The research, using Global Positioning System (GPS) satellite transmitters to track the movements of adolescent vultures, is published in the journal PLOS ONE.

The white-backed vulture is a widespread but declining species in Africa and it is now listed as endangered. In India, several vulture species are on the verge of extinction due to accidental poisoning from cattle carcasses that contain anti-inflammatory drugs administered by farmers. These drugs are non-lethal to cattle yet fatal to vultures. There is a concern that these drugs could become more widely used in Africa.

Vultures prefer to feed in savannah grassland habitats and away from other competing carnivores, such as lions, and the new study shows that the birds will go to considerable lengths to find food, crossing multiple state boundaries, with each bird on average ranging across an area twice the size of England.

Co-lead author, Dr Stephen Willis, School of Biological and Biomedical Sciences, Durham University, said: "We found that young vultures travel much further than we ever imagined to find food, sometimes moving more than 220 kilometres a day. Individuals moved through up to five countries over a period of 200 days, emphasising the need for conservation collaboration among countries to protect this species."

"In South Africa, the vultures avoided the national parks that have been established to conserve wildlife. As a result, these parks are unlikely to protect such a wide-ranging species against threats in the wider landscape.

"The vultures may actively avoid parks with numerous large mammal predators due to competition for food, and find easier pickings on cattle carcasses in farmland outside these protected areas.

"We found evidence that individual birds were attracted to 'vulture restaurants' where carrion is regularly put out as an extra source of food for vultures and where tourists can see the birds up close. As a result, these individuals reduced their ranging behaviour. Such 'restaurants' could be used in future to attract vultures to areas away from sites where they are at high risk of poisoning."

The team tracked six immature African white-backed vultures (Gyps africanus): five for 200 days, and one for 101 days) across southern Africa using GPS tracking units which were carefully strapped to the birds' backs.

Co-lead author, Louis Phipps, who recently graduated from the University of Pretoria, said: "Modern farming practices mean that vultures face an increasing risk of fatal poisoning. The provision of an uncontaminated supply of food, research into veterinary practices, and education for farmers could all be part of a future solution, if vulture numbers continue to plummet."

The work was funded by a Leverhulme Trust studentship to Louis Phipps. The research team included researchers from Durham University UK, University of Pretoria, South Africa and the Vulture Programme, North West Province, South Africa, with support from Mankwe Wildlife Reserve, South Africa.

Vulture facts:

• The vulture family includes the Californian and Andean Condors.
• A group of feeding vultures is called a wake.
• Vultures are found on every continent except Australia and Antarctica.
• A particular characteristic of many vultures is a bald head, devoid of normal feathers. This helps to keep the head clean when feeding. 
• Three species of south Asia's vultures are critically threatened with extinction: the Oriental white-backed, the long-billed and the slender-billed vulture - have declined by more than 97% since the early 1990s (source: RSPB).
• Vultures play an important role in Tibetan 'Sky burials' where a dead body is prepared and then exposed on a slab of rock for vultures and other scavengers to eat.

Contact: Carl Stiansen
[email protected]
44-019-133-46075
Durham University

Tapeworm eggs discovered in 270 million year old fossil shark feces

Fossilized tapeworm eggs in shark feces may be earliest known example of intestinal parasites in vertebrates

Spiral heteropolar coprolite with cestode eggs

A cluster of tapeworm eggs discovered in 270-million-year-old fossilized shark feces suggests that intestinal parasites in vertebrates are much older than previously known, according to research published January 30 in the open access journal PLOS ONE by Paula Dentzien-Dias and colleagues from the Federal University of Rio Grande, Brazil.

Remains of such parasites in vertebrates from this era are rare- of 500 samples examined, only one revealed the tapeworm eggs. This particular discovery helps establish a timeline for the evolution of present-day parasitic tapeworms that occur in foods like pork, fish and beef. The fossilized eggs were found in a cluster very similar to those laid by modern tapeworms. Some of them are un-hatched and one contains what appears to be a developing larva. According to the study, "This discovery shows that the fossil record of vertebrate intestinal parasites is much older than was previously known and occurred at least 270-300 million years ago."

The fossil described in this study is from Middle-Late Permian times, a period followed by the largest mass extinction known, when nearly 90% of marine species and 70% of terrestrial species died out.

Citation: Dentzien-Dias PC, Poinar G Jr, de Figueiredo AEQ, Pacheco ACL, Horn BLD, et al. (2013) Tapeworm Eggs in a 270 Million-Year-Old Shark Coprolite. PLoS ONE 8(1): e55007. doi:10.1371/journal.pone.0055007

Contact: Jyoti Madhusoodanan
[email protected]
415-568-4545
Public Library of Science

European ombudsman takes up PETA complaint

Paraskevas Nikiforos Diamandouros, European Obdusman.

Animal group claims European Chemical Agency guilty of maladministration

In response to a complaint by People for the Ethical Treatment of Animals (PETA), the European Ombudsman has launched an inquiry into the actions of the European Union (EU) agency responsible for the administration of the REACH chemical-testing program, which is expected to consume millions of animals in toxicity tests. PETA's complaint, submitted in July 2012, alleges that the European Chemicals Agency (ECHA) is not properly investigating cases in which animal testing could be avoided under the rules of REACH. PETA maintains that evidence derived from public documents and correspondence with the agency demonstrates that ECHA is not taking the necessary steps to ensure fulfilment of REACH's legal requirement that animal testing be conducted only as a "last resort."

The REACH Regulation (1907/2006/EU) makes clear in recitals, articles and annexes that animal tests must be avoided whenever possible, but in 2011 the agency's report "The Use of Alternatives to Testing on Animals for the REACH Regulation" showed that tens of thousands of animals were used in tests that could have been avoided under REACH's own rules. These tests included 135 skin-irritation studies conducted after a non-animal replacement had been validated and approved for use under REACH and 107 studies conducted without prior submission and approval of a testing proposal.

In response to the report, PETA contacted ECHA and the European Commission to seek assurances that all such possible violations of the requirements were being investigated by the agency and/or reported to relevant national authorities. PETA's enquiries have revealed that ECHA is not taking action to investigate all the 107 tests on animals conducted without test proposals, does not directly inform member state authorities of all possible violations of last-resort requirements and does not assess information dossiers submitted by chemical companies to evaluate whether animal tests undertaken for REACH could have been avoided.

In its complaint, PETA argued that in failing to properly evaluate whether animal tests had been conducted as a last resort in accordance with REACH's requirements, ECHA was guilty of maladministration. It is this complaint which the Ombudsman took up in December.

"PETA alleges that animals may have been poisoned and killed in tests that should never have taken place," says PETA UK Science Adviser Dr Gilly Stoddart. "We are relieved that the Ombudsman has launched an inquiry, as the lives of millions of animals are at stake. We trust that the Ombudsman will share our view and compel the agency to fulfil its obligations."

Contact: Tasgola Bruner
[email protected]
770-518-1675
People for the Ethical Treatment of Animals

New research shows complexity of global warming

Clouds over the Pacific. Credit: Shang-Ping Xie

Greenhouse gases versus solar heating

Global warming from greenhouse gases affects rainfall patterns in the world differently than that from solar heating, according to a study by an international team of scientists in the January 31 issue of Nature. Using computer model simulations, the scientists, led by Jian Liu (Chinese Academy of Sciences) and Bin Wang (International Pacific Research Center, University of Hawaii at Manoa), showed that global rainfall has increased less over the present-day warming period than during the Medieval Warm Period, even though temperatures are higher today than they were then.

The team examined global precipitation changes over the last millennium and future projection to the end of 21st century, comparing natural changes from solar heating and volcanism with changes from man-made greenhouse gas emissions. Using an atmosphere-ocean coupled climate model that simulates realistically both past and present-day climate conditions, the scientists found that for every degree rise in global temperature, the global rainfall rate since the Industrial Revolution has increased less by about 40% than during past warming phases of the earth.

Why does warming from solar heating and from greenhouse gases have such different effects on global precipitation?

"Our climate model simulations show that this difference results from different sea surface temperature patterns. When warming is due to increased greenhouse gases, the gradient of sea surface temperature (SST) across the tropical Pacific weakens, but when it is due to increased solar radiation, the gradient increases. For the same average global surface temperature increase, the weaker SST gradient produces less rainfall, especially over tropical land," says co-author Bin Wang, professor of meteorology.

But why does warming from greenhouse gases and from solar heating affect the tropical Pacific SST gradient differently?

"Adding long-wave absorbers, that is heat-trapping greenhouse gases, to the atmosphere decreases the usual temperature difference between the surface and the top of the atmosphere, making the atmosphere more stable," explains lead-author Jian Liu. "The increased atmospheric stability weakens the trade winds, resulting in stronger warming in the eastern than the western Pacific, thus reducing the usual SST gradient—a situation similar to El Niño."

Solar radiation, on the other hand, heats the earth's surface, increasing the usual temperature difference between the surface and the top of the atmosphere without weakening the trade winds. The result is that heating warms the western Pacific, while the eastern Pacific remains cool from the usual ocean upwelling.

"While during past global warming from solar heating the steeper tropical east-west SST pattern has won out, we suggest that with future warming from greenhouse gases, the weaker gradient and smaller increase in yearly rainfall rate will win out," concludes Wang.

Citation: Jian Liu, Bin Wang, Mark A. Cane, So-Young Yim, and June-Yi Lee: Divergent global precipitation changes induced by natural versus anthropogenic forcing. Nature, 493 (7434), 656-659; DOI: 10.1038/nature11784.

The International Pacific Research Center (IPRC) of the School of Ocean and Earth Science and Technology (SOEST), University of Hawaii at Manoa, is a climate research center founded to gain greater understanding of the climate system and the nature and causes of climate variation in the Asia-Pacific region and how global climate changes may affect the region. Established under the "U.S.-Japan Common Agenda for Cooperation in Global Perspective" in October 1997, the IPRC is a collaborative effort between agencies in Japan and the United States.

Contact: Gisela Speidel
[email protected]
808-956-9252
University of Hawaii ‑ SOEST

Snails signal a humid Mediterranean

An international team of researchers has shown that old wives' tales that snails can tell us about the weather should not be dismissed too hastily.

While the story goes that if a snail climbs a plant or post, rain is coming, research led by the University of York goes one better: it shows snails can provide a wealth of information about the prevailing weather conditions thousands of years ago.

The researchers, including scientists from the Scottish Universities Environmental Research Centre (SUERC), analysed the chemistry of snail shells dating back 9,000 to 2,500 years recovered from Mediterranean caves, looking at humidity at different times in the past.

Their findings, which are reported in the journal Quaternary International, reveal that when the first farmers arrived in Italy and Spain, the western Mediterranean was not the hot dry place it is now, but warmer, wetter and stickier.

The research was led by Dr André Carlo Colonese from York's Department of Archaeology.

Dr Colonese and his co-authors believe that land snails have great potential as a source of information about human behaviour and palaeoclimatic conditions and therefore should be given much more attention.

Dr Colonese, an EU Marie Curie Fellow in York's Centre for Human Palaeoecology & Evolutionary Origins, said: "By putting together research on snails from multiple sites across Spain and Italy, we were able to produce a large scale regional picture for weather conditions over the western Mediterranean area.

"This allowed us to observe differences in climate across the region. Interestingly, when compared with previous studies, we found that while conditions on the Atlantic coast of northern Spain were probably much like those of today, on the Mediterranean side in locations such as southern Spain and Sicily, conditions were much more humid."

Archaeological sites around the Mediterranean basin contain an abundance of land snail shell remains. The researchers selected well-preserved shells for isotopic analysis from the early to late Holocene layers, covering the Mesolithic, Neolithic, Chalcolithic and Bronze Age periods. They looked at the oxygen and carbon isotopic compositions of the shells of Pomatias elegans (or the round-mouthed snail as it is more commonly known), comparing those found in the Iberian Peninsula sites with modern shells of the same species.

Co-author Dr Giovanni Zanchetta, from the Earth Science Department at the University of Pisa, Italy, said: "Stable isotopes on land snail shells have represented a challenge for researchers for years, but using archeological well-dated sites, new fundamental insight on past climate are coming along. And we are just at the beginning because there are a lot of excavations which can yield rich material."

The shell stable isotope measurements were carried out at SUERC, East Kilbride, Scotland, using a mass spectrometer. Further analysis was performed at the Cornell Stable Isotope Laboratory in the United States.

Co-author Professor Tony Fallick of SUERC and Professor of Isotope Geosciences at the University of Glasgow said: "This is a classic example of multidisciplinary research where colleagues from a variety of backgrounds including archaeology, climate and environmental science, and geochemistry collaborate to deliver insights into our recent past that have societal impact."

Contact: Caron Lett
[email protected]
44-019-043-22029
University of York

EU LIFE Unit: A fresh face prepares to tackle fresh challenges

Anne Burrill deputy head of the LIFE Nature 
and Biodiversity Unit.

Anne Burrill took up the post of deputy head of the LIFE Nature and Biodiversity Unit last July. In this interview she looks ahead to new challenges for the Unit in 2013 and explains why the LIFE programme continues to be a vital funding tool more than two decades years after it was launched.

Anne Burrill sees “a series of challenges” for the LIFE Nature and Biodiversity Unit in the year ahead. “The first is getting all of the 2012 applications evaluated and managing the projects that are already on the table; in view of the fact that we are constantly receiving more applications and managing more projects, that's an operational challenge.”

Beyond this, she says the unit faces “two types of challenges” at this point in time. “The first one is to reinforce the integration between LIFE projects and the policy agenda. Specifically for LIFE Nature, we are trying to link up the Natura 2000 Bio-geographical Process to LIFE, both to ensure that the Natura 2000 process is taking as much advantage as possible of the lessons of LIFE projects, and also to make sure that in the future we can reflect the priorities and needs that are coming out of the Bio-geographical Seminars in our future calls. We are also working to extract lessons from closed and ongoing LIFE projects in relation to key policy issues such as invasive alien species and the management of large carnivore populations.”

Alongside this there is the second, “very real” challenge “of adjusting our way of working, our planning, our whole operations to the future - to the expected LIFE instrument for 2014-2020 and also to the very likely upcoming externalisation of the implementation of the LIFE programme to an EU executive agency,” says Ms Burrill.

The Commission's proposal to make greater use of the EU executive agencies for the management of EU programmes under the next multi-annual financial framework is “not specific to LIFE”, explains Ms Burrill. “It is also proposed, for example, that the research programme will be externalised to an agency. The intention is that this is going to lead eventually to cost savings and increases in efficiency.”

The deputy head of unit sees a number of challenges to be tackled in making this proposed transition: “Obviously we have to help the agency to set up its new procedures, to train its new staff; we also have to figure out how to continue to ensure the link between the LIFE programme and the EU's environmental policy agenda, which for us is very, very important.”

Ms Burrill adds that, “since we don't yet have a firm confirmation if or when this externalisation will happen, we're planning a little bit in a vacuum at the moment. But, if as is expected, the new programme should be externalised from 2014, it's obviously something that we need to get moving on.”

In the meantime, there is the pressing matter of the 2013 call for proposals to deal with. “The 2013 call will be very similar to the 2012 call,” says Ms Burrill. “Considering it's the last year of the programme under the present LIFE regulation, we don't really think it's the time to start introducing big innovations.  However, something that is relatively recent - since 2011 - is the introduction of the Natura 2000 management and restoration programme projects.” She explains that these so-called PAF projects “are intended to support in some way the development of the national Priority Action Frameworks for the implementation of Natura 2000 across Europe. We see the PAF projects very much as useful in their own right, but also as potential precursors for the integrated projects that might be submitted under the future LIFE instrument. So we certainly hope that applicants will take full advantage of this possibility. and that we will see more applications for PAF projects in response to the 2013 LIFE call.”

Integrated projects are an important aspect of the Commission's proposal for a follow-up LIFE instrument for the period 2014 to 2020 and one that has in general been warmly received by the European Council and Parliament, says Ms Burrill. However, the precise nature of any ongoing LIFE programme remains uncertain until the budget for the next multiannual financial framework is agreed. “If there is a significant change to the level of the budget, then we may need to do some serious re-thinking about the structure of the programme, including about the extent to which we can actually introduce these new integrated projects. Furthermore, if we do not have a regulation adopted by next June, which is a possibility, it's going to be very hard to be prepared to launch a call in 2014,” she cautions.

LIFE adds value

In addition to its core objective of supporting the development and implementation of EU policies on nature and biodiversity, Ms Burrill is keen to point out that LIFE projects can have additional benefits. “It is our firm belief in DG Environment that, good nature and biodiversity policy does produce overall social and economic dividends. I think you can see individual projects where there are very immediate dividends, and those are the ones that have been highlighted up to now. But I think that many more of the LIFE Nature projects actually do have indirect and long-term social and economic dividends. So beyond designing projects for such added value outcomes, I think we need to look more at what added value is coming out of the projects, including indirectly, and make sure that this is identified, understood and articulated.”

Improving the visibility of the outcomes of LIFE projects is an important goal in general, says Ms Burrill. “The lessons from LIFE projects can make an important contribution towards reaching the ambitious aims of the EU's nature and biodiversity policy, including the good functioning of the Natura 2000 network. This is something that we are working on through our communications programme, through the booklets and brochures that we have put together. We want to ensure that the money that the taxpayer has invested in the LIFE programme has as great an impact as possible.”

To this end, she is very pleased to note that as part of the LIFE20 celebrations in 2012, in addition to half a dozen events with very high level participation, “there were about 320 events at the local or regional level. That's great because it means that our message is being diffused to a much larger number of people on a much more personal level and they really can see and understand what LIFE has done.”

According to Ms Burrill, “a good LIFE project is one that makes a lasting difference, not only in the project site, but more broadly...[It] will serve as a model for action elsewhere: it will provide evidence of how certain techniques can be applied on the ground; it will show perhaps how integration can function in practice. A successful project will often set out to - and successfully - change the opinions of some stakeholders. In other words, a really successful LIFE Nature or Biodiversity project does what it should do on the ground, but it also has broader repercussions that contribute more widely to the good management and protection of Europe's natural capital.”

More relevant than ever

Ms Burrill concludes by stating that, as EU environment policy continues to develop, the LIFE programme today is even more important and relevant than it was when it was introduced in 1992. "The EU citizen understands the importance of good management of our environment and as a result EU environment policy is very far-reaching and ambitious. However, we know that there's still a lot to be done to ensure that EU environment policy is implemented in practice; through LIFE we can finance pilot projects and catalyse action. LIFE is the instrument to support the implementation of EU environment policy and to support its future development through practical, on-the-ground experience."

 

The Future: Six Drivers of Global Change.

The Future: Six Drivers of Global Change

Dear Constantine,

Almost a decade ago, someone asked me a question, “what are the drivers of global change?” I’ve spent a lot of time over the last eight years thinking about it, and have dedicated the last two years to researching, writing and refining my conclusions. The result is my new book, The Future: Six Drivers of Global Change.

 

We are living in a time of rapid, simultaneous and exponential change, unlike anything the world has ever seen. From revolutionary changes in our economy and our climate, to advances in life sciences and the digital realm, the future holds great opportunities but also profound challenges.

We have a choice.

Will we be swept along by the currents of technological change and economic determinism, or will we unite behind a future that preserves human dignity and reflects the aspirations of global citizens? Together we have an important role to play in reclaiming control of our destiny, but it starts with a global conversation.

While mapping the future is a risky undertaking, perhaps the only thing riskier is doing nothing.

Thank you,

Al Gore

• The Wall Street Journal Book Review
• The New York Times Book Review
• The Guardian Book Review

Spring may come earlier to North American forests

Trees in the continental U.S. could send out new spring leaves up to 17 days earlier in the coming century than they did before global temperatures started to rise, according to a new study by Princeton University researchers. These climate-driven changes could lead to changes in the composition of northeastern forests and give a boost to their ability to take up carbon dioxide.

Trees play an important role in taking up carbon dioxide from the atmosphere, so researchers led by David Medvigy, assistant professor in Princeton's department of geosciences, wanted to evaluate predictions of spring budburst — when deciduous trees push out new growth after months of winter dormancy — from models that predict how carbon emissions will impact global temperatures.

The date of budburst affects how much carbon dioxide is taken up each year, yet most climate models have used overly simplistic schemes for representing spring budburst, modeling for example a single species of tree to represent all the trees in a geographic region.

In 2012, the Princeton team published a new model that relied on warming temperatures and the waning number of cold days to predict spring budburst. The model, which was published in the Journal of Geophysical Research, proved accurate when compared to data on actual budburst in the northeastern United States.

In the current paper published online in Geophysical Research Letters, Medvigy and his colleagues tested the model against a broader set of observations collected by the USA National Phenology Network, a nation-wide tree ecology monitoring network consisting of federal agencies, educational institutions and citizen scientists. The team incorporated the 2012 model into predictions of future budburst based on four possible climate scenarios used in planning exercises by the Intergovernmental Panel on Climate Change.

The researchers included Su-Jong Jeong, a postdoctoral research associate in Geosciences, along with Elena Shevliakova, a senior climate modeler, and Sergey Malyshev, a professional specialist, both in the Department of Ecology and Evolutionary Biology and associated with the U.S. National Oceanic and Atmospheric Administration's Geophysical Fluid Dynamics Laboratory.

The team estimated that, compared to the late 20th century, red maple budburst will occur 8 to 40 days earlier, depending on the part of the country, by the year 2100. They found that the northern parts of the United States will have more pronounced changes than the southern parts, with the largest changes occurring in Maine, New York, Michigan, and Wisconsin.

The researchers also evaluated how warming temperatures could affect the budburst date of different species of tree. They found that budburst shifted to earlier in the year in both early-budding trees such as common aspen (Populus tremuloides) and late-budding trees such as red maple (Acer rubrum), but that the effect was greater in the late-budding trees and that over time the differences in budding dates narrowed.

The researchers noted that early budburst may give deciduous trees, such as oaks and maples, a competitive advantage over evergreen trees such as pines and hemlocks. With deciduous trees growing for longer periods of the year, they may begin to outstrip growth of evergreens, leading to lasting changes in forest make-up.

The researchers further predicted that warming will trigger a speed-up of the spring "greenwave," or budburst that moves from south to north across the continent during the spring.

The finding is also interesting from the standpoint of future changes in springtime weather, said Medvigy, because budburst causes an abrupt change in how quickly energy, water and pollutants are exchanged between the land and the atmosphere. Once the leaves come out, energy from the sun is increasingly used to evaporate water from the leaves rather than to heat up the surface. This can lead to changes in daily temperature ranges, surface humidity, streamflow, and even nutrient loss from ecosystems, according to Medvigy.

Citation: Jeong, Su-Jong, David Medvigy, Elena Shevliakova, and Sergey Malyshev. 2013. Predicting changes in temperate forest budburst using continental-scale observations and models. Geophysical Research Letters. Article first published online: Jan. 25, 2013. DOI: 10.1029/2012GL054431

Contact: Catherine Zandonella
[email protected]
Princeton University

Cultural evolution changes bird song

Savannah sparrow on Kent Island, N.B. Credit: Rolf Nagel

Thanks to cultural evolution, male Savannah sparrows are changing their tune, partly to attract "the ladies."

According to a study of more than 30 years of Savannah sparrows recordings, the birds are singing distinctly different songs today than their ancestors did 30 years ago – changes passed along generation to generation, according to a new study by University of Guelph researchers.

Integrative biology professors Ryan Norris and Amy Newman, in collaboration with researchers at Bowdoin College and Williams College in the U.S., analyzed the songs of male Savannah sparrows (Passerculus sandwichiensis) recorded over three decades, and found that the songs had changed distinctly from 1980 to 2011.

"The change is the result of cultural transmission of different song elements through many generations," said Norris.

Norris added that the change in tune resembles changes in word choice and language among humans.

Young Savannah sparrows on Kent Island, N.B. The young male sparrows learn the song they will sing for their lifetimes from those older male birds around them. Credit: Amy Newman

"If you listen to how people used to talk in the 1890s and how we talk today, you would notice major differences, and this is the result of shifts in culture or the popularity of certain forms," he said. "The change in sparrow songs over time has occurred much the same way"

The sparrows, which live on Kent Island, N.B., in the Bay of Fundy, can generally sing only one song type that consists of several parts. Male sparrows learn that song early in their first year and continue to sing the same tune for the rest of their lives.

"Young male sparrows learn their songs from the birds around them," said Norris. "It may be their fathers, or it could be other older male birds that live nearby."

Each male sparrow has his own unique sound, added Newman.

"While the island's sparrows all sing a characteristic 'savannah sparrow song,' with the same verses and sound similar, there are distinct differences between each bird," she said. "Essentially, it is like karaoke versions of popular songs. It is the rise and fall in popular cover versions that has changed over time."

 

The research team found that, in general, each song has three primary elements. The first identifies the bird as a Savannah sparrow, the second identifies which individual is singing, and the third component is used by females to assess males.

Using sonograms recorded from singing males each breeding season, the researchers determined that, while the introductory notes had stayed generally consistent for the last 30 years, the sparrows had added a series of clicks to the middle of their songs. The birds had also changed the ending trill: once long and high-frequency, it is now shorter and low-frequency.

"We found that the ending trill of the song has become shorter, likely because female sparrows preferred this, because males with shorter trills had higher reproductive success," Norris said.

Kent Island has been home to the Bowdoin Scientific Station since it was donated by J. Sterling Rockefeller in 1932, and the birds have been recorded since the 1980s. Individual birds are also monitored throughout their lifetime.

"We know the identity and history of every single sparrow in the study population" said Norris, who has led the project with Newman since 2009. "To have 30 years of recordings is very rare, and it was definitely surprising to see such drastic changes."

 

Contact: Ryan Norris
[email protected]
519-824-4120 x56300
University of Guelph

New evidence highlights threat to Caribbean coral reef growth

Many Caribbean coral reefs have either stopped growing or are on the threshold of starting to erode, new evidence has revealed

Coral reefs build their structures by both producing and accumulating calcium carbonate, and this is essential for the maintenance and continued vertical growth capacity of reefs. An international research team has discovered that the amount of new carbonate being added by Caribbean coral reefs is now significantly below rates measured over recent geological timescales, and in some habitats is as much as 70% lower.

Coral reefs form some of the planet's most biologically diverse ecosystems, and provide valuable services to humans and wildlife. However, their ability to maintain their structures and continue to grow depends on the balance between the addition of new carbonate, which is mostly produced by corals themselves, set against the loss of carbonate through various erosional processes. Scientists have long known that reef ecosystems are in decline and that the amount of live coral on reefs is dwindling. But the paper, published on DATE TBC in Nature Communications, is the first evidence that these ecological changes are now also impacting on the growth potential of reefs themselves.

Professor Chris Perry of the University of Exeter, who led the research, said: "Our estimates of current rates of reef growth in the Caribbean are extremely alarming. Our study goes beyond only examining how much coral there is, to also look at the delicate balance of biological factors which determine whether coral reefs will continue to grow or will erode. Our findings clearly show that recent ecological declines are now suppressing the growth potential of reefs in the region, and that this will have major implications for their ability to respond positively to future sea level rises.

"It is most concerning that many coral reefs across the Caribbean have seemingly lost their capacity to produce enough carbonate to continue growing vertically, whilst others are already at a threshold where they may start to erode. At the moment there is limited evidence of large-scale erosion or loss of actual reef structure, but clearly if these trends continue, reef erosion looks far more likely. Urgent action to improve management of reef habitats and to limit global temperature increases is likely to be critical to reduce further deterioration of reef habitat."

The team was funded by the Leverhulme Trust (UK), through an International Network Grant. It included scientists from James Cook University and the University of Queensland in Australia, from the University of Auckland in New Zealand, Memorial University in Canada, and the University of Maine in the USA. They examined rates of carbonate production across 19 reefs in the four Caribbean countries of the Bahamas, Belize, Bonaire and Grand Cayman.

They discovered that declines in rates of carbonate production were especially evident in shallow water habitats, where many fast growing branching coral species have been lost. The study compared modern day rates with those measured in the region over approximately the last 7,000 years. In key habitats around the Caribbean, the findings suggested that in waters of around five metres in depth, reef growth rates are now reduced by 60-70% compared to the regional averages taken from historical records. In waters of around 10 metres in depth, the rates are reduced by 25%.

The study also suggests that these key habitats must have a minimum of around 10% living coral cover to maintain their current structures. The amount of cover varies between sites, but some are already below this threshold and are therefore at risk of starting to erode. Given that previous studies have shown that coral cover on reefs in the Caribbean has declined by an average of 80 per cent since the 1970s, this raises alarm bells for the future state of reefs in the region. These changes have been driven by human disturbance, disease and rising sea temperatures, and are only expected to intensify as a result of future climate change.

Contact: Louise Vennells
[email protected]
0044-013-927-22062
University of Exeter