2012/09/19

Cold War Offered Odd Benefit -- It Limited Species Invasions

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ScienceDaily (Jan. 8, 2010) A recent study about movement of bird species during the Cold War outlines one of the perils facing an expanding global economy -- along with international trade comes the potential for a significant increase in invasive species that can disrupt ecosystems.


This alien, destructive parakeet is currently expanding its range across Western Europe. It can be a serious agricultural pest and competes with native birds for nesting cavities. (Credit: Photo courtesy of Oregon State University)
The research found that during an extended period following World War II, when most trade and travel was interrupted between Eastern Europe and its western counterparts, there were far fewer introduced bird species.
"Last year, people worldwide celebrated the 20th anniversary of the fall of the Iron Curtain and the end of the Cold War," said Susan Shirley, a research associate in the College of Forestry at Oregon State University. "This signified a time of renewed freedom and opportunities for the countries of Eastern Europe. However, those new opportunities brought new challenges from an unexpected source."
The problem, Shirley said, is that there's often a correlation between politics, trade and ecosystem function.
"Global trade is a real concern for invasive species, and the lessons we can learn from the Cold War offer a warning flag to developing countries that are now expanding in an international economy," Shirley said.
Control or eradication of invading species is extremely difficult and expensive, Shirley said, and prevention of animal importation is the only sure approach to address this problem. It relates not just to birds, which were the focus of this research, but to forest pests, fisheries, non-native crustaceans and many other species.
Even though birds, in theory, need pay little attention to international borders, in fact they tend to stay in native habitats. However, they sometimes establish populations in new locales if they are brought there, Shirley said.
"Traditionally we don't hear much about birds as an invasive species, but they can be," she said.
"The common myna, a subtropical bird, is a generalist predator and a crop pest, and has been included on a list of the 100 worst invasive species," Shirley said. "The collard dove is a habitat generalist and has now spread all over Europe. And of even more concern, there are several species with serious impacts in other regions of the world that may be in the process of establishing populations in Europe, largely due to the escape of wild-caught pet birds."
The study, published recently in the journal Biological Conservation, found that prior to the Cold War, Western Europe had 36 non-European introduced species and Eastern Europe had 11. By the time that period of international tension and restricted trade ended, Western Europe had experienced an increase to 54 non-European introduced bird species, but Eastern Europe had actually declined from 11 to five.
"The isolation of the Eastern European bloc from the west during the Cold War led to a decline in the number of birds introduced, the number of introduction events and the number of bird species established," the study authors wrote in their report.
In light of that, the researchers suggest that clear policies need to be established to prevent further inflow of exotic species into previously isolated regions, and warn that the problems illustrated by this phenomenon in Europe may play out in similar ways all over the world as trade expands.
The unusual isolation of Eastern Europe for more than four decades provided a unique opportunity to study the effect of socio-economic and political factors on invasive species, the researchers said. In that context, eastern European ecosystems actually benefited from the isolation, scientists said, and also provide insight into how invasive species problems can be reduced with more aggressive regulation and monitoring.

Ecologists Sound out New Solution for Monitoring Cryptic Species

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ScienceDaily (Nov. 28, 2009)Ecologists have at last worked out a way of using recordings of birdsong to accurately measure the size of bird populations. This is the first time sound recordings from a microphone array have been translated into accurate estimates of bird species' populations. Because the new technique, reported in the British Ecological Society's Journal of Applied Ecology, will also work with whale song, it could lead to a major advance in our ability to monitor whale and dolphin numbers.

Developed by Deanna Dawson of the US Geological Survey and Murray Efford of the University of Otago, New Zealand, the technique is an innovative combination of sound recording with spatially explicit capture-recapture (SECR), a new version of one of ecologists' oldest tools for monitoring animal populations.
Birds communicate by singing or calling, and biologists have long counted these cues to get an index of bird abundance. But it is much harder to work out the actual density of a bird population because existing methods need observers to measure either the distance to each bird, or whether they are within a set distance from the observer. This is straightforward if birds are seen, but difficult when birds are heard but not seen.
According to Dawson: "We devised a way to estimate population density of birds or other animals that vocalise by combining sound information from several microphones. A sound spreading through a forest or other habitat leaves a 'footprint'. The size of the footprint depends on how quickly the sound attenuates. Mathematically, there is a unique combination of population density and attenuation rate that best matches the number and 'size' of the recorded sounds. We used computer methods to find the best match, and thereby estimate density."
Dawson and Efford developed the method by recording the ovenbird -- a warbler more often heard than seen -- in deciduous forest at the Patuxent Research Refuge near Laurel, Maryland, USA. They rigged up four microphones close to the ground in a square with 21 metre-long sides. Over five days, they moved the microphones to 75 different points across their study area and recorded ovenbirds singing.
They chose the ovenbird as the species from which to develop the method because of its concise, distinctive song and because the males sing from the lower layers of the forest.
The new acoustic technique gives a more accurate estimate of bird numbers than using nets to capture birds, which can be stressful for the birds as well as time consuming for the researchers.
As well as helping assess populations of cryptic bird species such as the ovenbird, the new technique might be applied to measuring hard-to-reach populations of marine mammals, such as whales and dolphins. Developing ways of estimating whale and dolphin numbers acoustically is seen as critical for understanding these species' populations.
Recording the sounds has other benefits, too. "Sound intensity and other characteristics can be measured from the spectrogram -- the graph of the sounds -- to improve density estimates. Archiving the sounds also makes it possible to re-examine them, or to extract additional information as analytical methods evolve," says Dawson.

Follow the Money: Wealth, Population Are Key Drivers of Invasive Species

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ScienceDaily (June 9, 2010) — A new study of biological invasions in Europe found they were linked not so much to changes in climate or land cover, but to two dominant factors -- more money and more people.


This alien, destructive parakeet is currently expanding its range across Western Europe. It can be a serious agricultural pest and competes with native birds for nesting cavities. (Credit: Photo courtesy of Oregon State University)
Wealth and population density, along with an increase in international trade and commerce, were the forces most strongly associated with invasive species that can disrupt ecosystems and cause severe ecological or agricultural damage, scientists said.
An international group of 26 researchers reported the new findings this week in Proceedings of the National Academy of Sciences.
Dealing with these issues will be "pivotal for policy makers and future management," the researchers said, although no easy or inexpensive solutions exist, and many nations have been reluctant to take steps that might interfere with economic growth.
"Invasive species are a continuing and extensive ecological crisis, and we're finding that human population and accumulated wealth are important drivers of this problem," said Susan Shirley, a research assistant in the Department of Forest Ecosystems and Society at Oregon State University, and co-author on this study.
"Regional patterns of species invasions are complex, and there is still unexplained variation, likely due to local scale differences in several of the ecological factors," Shirley said. "But invasive species are in large part an international trade issue, and this is an important problem we have not yet come to grips with. Next to population density, the closest correlation is to long-standing wealth, not more recent increases in income or economic activity."
Human activities often related to trade, travel and transport, particularly in the past 50 years, have caused a surge in the number of introduced species, ranging from plants to fungi, insects, fish, birds, reptiles and mammals. Some are innocuous, but many displace native species and cause a range of ecosystem disruption. As a crossroads of international travel and trade, with both a high population and high income, Europe has experienced many invasive species.
The study concluded that other possible factors, such as climate, geography or land cover, were less significant than population density and wealth capital, and that those secondary causes may have been overestimated in the past.
The mechanisms of species invasion are often associated with international trade. Invasive species can hitch-hike on imported products, be brought to new regions as pets, be associated with contaminated food, or even introduced on purpose, as in the case of some ornamental plants or new crops.
In another recent study, Shirley and her colleagues researched bird introductions in Europe, and the findings supported this premise. Trade with Eastern Europe was severely disrupted for decades during the Cold War. By the end of that long period of international tension and restricted trade, Western Europe had experienced an increase in invasive bird species, but numbers in Eastern Europe actually declined.
In the new study, researchers were able to predict the number of alien species in Europe to a reasonably high degree simply by defining the level of wealth and the number of people.
"The overwhelming effect of human factors, wealth and demography, found for several taxonomic groups translates to human activities responsible for enhancing biological invasions," researchers wrote in the study.
Solving this problem will not be easy, the study suggested.
Identifying the specific mechanisms of invasion is critical. Monitoring may need to be improved. Legislation to restrict or regulate certain imports will likely be needed, in addition to charging fees or tariffs that would help deal with invasive species when they occur. But the World Trade Organization and other international agreements "have no effective mechanisms" to address this concern, the authors said. And aside from good intentions, restrictions could be costly.
A major challenge, Shirley said, will be to understand the specific economic factors leading to introductions so they can be effectively addressed while minimizing negative impacts on international trade. These factors are likely to differ among species. For example, minimizing releases of vertebrate species might require additional regulation of the pet trade, while a focus on transport infrastructures such as roads may help control introductions of alien invertebrates.
"Nations do not have a good track record in forsaking future economic prosperity for environmental benefits," the study concluded. "Only if the true determinants are identified will it be possible to predict and manage alien species invasions adequately without adverse effects on other economic sectors."

11,000 Alien Species Invade Europe

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ScienceDaily (Nov. 20, 2008)For the first time it is now possible to get a comprehensive overview of which alien species are present in Europe, their impacts and consequences for the environment and society. More than 11,000 alien species have been documented by DAISIE (Delivering Alien Invasive Species Inventory for Europe), a unique three year research project with more than 100 European scientists, funded by the European Union that provides new knowledge on biological invasions in Europe.

Biological invasions by alien species often result in a significant loss in the economic value, biological diversity and function of invaded ecosystems.
Harmful visitors
The majority of these 11,000 alien species are however, not harmful. About 15 percent of these alien species cause economic damages and 15 percent cause harm to biological diversity, that is the environment, habitats and native plants, animals and micro-organisms, according to findings in the newly released and freely accessible web portal at http://www.europe-aliens.org and the DAISIE "Handbook of alien species in Europe" that is launched this week.
Knowledge enables action
Previous to the publication of the results of the DAISIE project, the number and impacts of harmful alien species (also called invasive alien species) in Europe has been underestimated, especially for species that do not damage agriculture, forestry or human health. The lack of knowledge has contributed to inaction in many European countries which is becoming increasingly disastrous for Europe’s biodiversity, health and economy.
Why do we need the information?
Alien species may have a profound impact on the environment and society as they can act as vectors for new diseases, alter ecosystem processes, change biodiversity, disrupt cultural landscapes, reduce the value of land and water for human activities and cause other socio-economic consequences. Alien species are plants, animals and micro-organisms that have been moved by humans to new environments outside of the range they occupy naturally.
Publication: DAISIE (2009) Handbook of alien species in Europe. Springer, Dordrecht, ISBN 978-1-4020-8279-5, available by 17 November 2008

Why Claws Come out Over Feral Cat Management: Finding Common Ground Among 'Cat People' and 'Bird People'

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ScienceDaily (Sep. 6, 2012) — The contentious phenomenon of identity politics isn't limited to Democrats and Republicans. A national survey shows that "cat people" and "bird people" have heated differences of opinion, complicating the challenge of managing more than 50 million free-roaming feral cats while protecting threatened wildlife.


Cats in a feral colony sun themselves on a wall. (Credit: Photo courtesy of Alisa Davis, University of Hawaii at Manoa)
A North Carolina State University study published Sept. 6 in PLoS ONE identifies why the claws come out over feral cat management and which approaches might be useful in finding common ground among those with polarized opinions.
The research started as a hands-on class project for undergraduate and graduate students in Dr. Nils Peterson's Human Dimensions of Wildlife course last year. Team members surveyed 577 people across the U.S. who identified themselves as cat colony caretakers or bird conservation professionals affiliated with groups such as the Audubon Society and American Bird Conservancy.
"Members of both these groups feel they have concerns that have been ignored," says Peterson, an associate professor of fisheries, wildlife and conservation biology in the College of Natural Resources. "This feeling of injustice is part of what leads them to identify with their groups."
Bird conservation professionals, whose focus is on protecting species from extinction in the wild, see feral cats as threats to the survival of wild birds. Cat colony caretakers, on the other hand, dedicate themselves to caring for neighborhood animals they see as abandoned and neglected by others.
The polarized points of view led to wide differences in responses to factual statements about feral cat management and disagreement about the impact of feral cats on wildlife.
Only 9 percent of cat colony caretakers believed cats harmed bird populations, and only 6 percent believed feral cats carried diseases. Colony caretakers supported treating feral cats as protected wildlife and using trap, neuter and release programs to manage feral cat populations.
Many bird conservation professionals, meanwhile, saw feral cats as pests and supported removing and euthanizing them. Within both groups, women and older respondents were less likely to support euthanasia.
"The most surprising result was that cat colony caretakers were more amenable to seeking collaborative solutions to feral cat management than bird conservation professionals," Peterson says. "Eighty percent of the cat caretakers thought it was possible, while 50 percent of the bird conservationists felt that it was."
How could the groups take steps to work together in the face of differing opinions about the scientific evidence?
Peterson says part of the solution is getting buy-in. Cat colony caretakers would have to be involved in deciding which data should be collected and how and where it should be done. When possible, participants should be able to see results for themselves rather than relying on reports from another group. One example: observing firsthand that feral cats kill wildlife rather than reading studies that show feral cats contribute to global declines among songbird populations. Another possibility is training cat colony caretakers to recognize parasites or signs of disease in the animals they see regularly, improving the cats' health and caretakers' knowledge.
Finally, the groups should recognize they share the common ground of caring about animals. In fact, half of the bird conservation professionals owned and cared for cats. Peterson also hopes his students have

Picky Penguins: Does Mate Choice Depend On Genes That Help Resist Disease?

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ScienceDaily (Sep. 4, 2012)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.


Magellanic penguins. (Credit: Photo courtesy of J. L. Bouzat)
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 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."

Albatross 'Dynamic Soaring' Achieved by Repeated Curve-Altitude Oscillation

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ScienceDaily (Sep. 5, 2012)Albatrosses leverage the energy of the wind to fly with essentially no mechanical cost to themselves, very rarely flapping their wings. New work offers insight into how exactly they accomplish this feat.


Wandering Albatross (Diomedea exulans) in flight, East of the Tasman Peninsula, Tasmania, Australia. (Credit: JJ Harrison (jjharrison89@facebook.com) (Own work) [CC-BY-SA-3.0], via Wikimedia Commons)
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.
They determined 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.
The research was published Sept. 5 in the open access journal PLoS ONE.

Europe's Flora Is Becoming Impoverished

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ScienceDaily (Dec. 18, 2009)With increasing species richness, due to more plant introductions than extinctions, plant communities of many European regions are becoming more homogeneous. The same species are occurring more frequently, whereas rare species are becoming extinct.


The Giant Hogweed (Heracleum mantegazzianum) are up to four metres high. It can cause third-degree burns because of the extremely aggressive sap inside the plant. (Credit: André Künzelmann/UFZ)
It is not only the biological communities that are becoming increasingly similar, but also the phylogenetic relations between regions. These processes have led to a loss of uniqueness among European floras, scientists from the DAISIE research project have published their findings in the current online edition of the scientific journal Proceedings of the National Academy of Sciences of the USA (PNAS).
For their research the scientists analysed the data of flora native to Europe (Flora Europaea), extinct plant species (national red lists) and alien plant species from the DAISIE database. About 1,600 new non-European species were introduced to the approx. 11,000 native European plant species since 1500 A.D. The researchers also took into account those European plants that are native to a particular region of Europe but considered as introduced species in another (approx. 1,700. It works in a similar way for the species considered to be "extinct." While in the whole of Europe only 2 plant species can "really" be considered as extinct, approx. 500 species have become locally extinct. One such example is the Blue Woodruff (Asperula arvensis), a weed that grows on cultivated land, which has been greatly displaced particularly from the intensification of agricultural practices. This species is considered to be locally extinct in Germany and Austria for example, whereas it still occurs e.g. in Italy and Spain.
The researchers were able to demonstrate, that biodiversity is increasing in all regions of Europe due to high numbers of alien species. But at the same time the plant communities of the regions are becoming increasingly more homogenous because alien species are distributed relatively consistently over the continent. The remarkable thing is that it is not only the diversity between plant communities that is decreasing (taxonomic homogenisation), but also the phylogenetic diversity.
Phylogenetic diversity reflects the evolutionary history of a community and therefore also its genetic diversity, which can also be an expression of its functional diversity. A phylogenetic tree with high diversity can be imagined as a genealogical tree with a protruding crown, with many strong branches (distantly related species) and numerous twigs (many species). A high phylogenetic and taxonomic diversity (many tree species that look different), presents a wealth of information and ability, making it possible for biological communities to react to environmental changes, like those arising for example from the current global climate change (e.g. climate or land use change). If one finds many very similar looking trees, then one assumes that the flexibility of the communities is no longer as high to be able to react positively to these changes. Put simply: the genealogical tree of the plant species occurring in Europe has got more twigs, but these only sprout from a few large branches.
Biological depletion from loss of species and introduced species is a consequence of global change associated with increasing pressure on the environment (e.g. the intensification of agriculture, the loss of habitat diversity, urbanisation, increasing global traffic and excessive nutrient influx into ecosystems).
"Our studies have shown that in spite of an increase in regional species richness due to species introductions exceeding the local extinctions of plant species in European regions, these are increasingly losing both their phylogenetic and taxonomic uniqueness," according to Dr. Marten Winter from the Helmholtz Center for Environmental Research (UFZ). "In all discussions on `biodiversity' one needs to consider other forms of biodiversity than pure species richness e.g. those of phylogenetic relations. These can supply additionally important information about the condition and possible risks to ecosystems ," the researcher adds.
Over the last few years, the EU project DAISIE (Delivering Alien Invasive Species Inventories for Europe) has gathered for the first time information on all known alien species across Europe. Information on the ecology and distribution of alien plant and animal species was collected and has been made available for interested parties via an Internet database. Research institutes and organizations from 15 nations were involved in the project.

Invasive Species: Will Europe At Last Unite To Combat Thousands Of Alien Invaders?

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ScienceDaily (Apr. 12, 2009)Europe’s borders have been breached by thousands of plants and animal species from other parts of the world: from the American mink to the New Zealand flatworm. The invaders feed on, hybridise with, parasitise and out-compete native species. They also introduce diseases, alter the balance within ecosystems, modify landscapes and impact upon agriculture, forestry and fisheries. 


The American mink (Mustela vison) is a generalist and opportunist predator introduced from North America for the fur farming industry. Meanwhile the European mink (Mustela lutreola), whose range is now restricted to a few fragmented populations, is threatened by the American mink through competition by means of direct aggression. (Credit: André Künzelmann/UFZ)
Preliminary estimates indicate that the monetary cost of these invasive alien species in Europe amounts to at least €10 billion per year, yet for 90% of species almost nothing is known of their impacts.
Recent evidence that Europe may be home to 11,000 alien species has spurred the European Commission to release its first ever Communication on invasive species. The European Environment Commissioner, Stavros Dimas, noted at the launch of the Communication that “the ecological, economic and social consequences of the spread of invasive species for EU countries are serious and need a harmonised response”.
The Communication, which is currently open for consultation, proposes the development of a European Strategy on Invasive Species. It outlines three potential ways forward, each representing a different level of legislative cost and complexity. The first, and least complex, involves making better use of existing legislation; the second would adapt existing legislation to address invasive species, while the third, and most complex, would develop a dedicated legal instrument.  But is this the best way forward?
A recent paper published in the journal Science suggests legislation is only part of the answer and that what Europe lacks is appropriate governance and institutional coordination across Member States to tackle the problem of invasions effectively.
“Currently, responsibility for invasive species management sits within too many different European Institutions. These are organisations such as the European Environment Agency (EEA), European and Mediterranean Plant Protection Organisation (EPPO), European Food Safety Authority (EFSA) that rarely communicate with each other and where the topic of invasions is only one of many areas of activity” says Philip Hulme lead author of the paper.
“This system is not effective. For example EPPO and EFSA have not seen eye to eye when it comes to assessing the risks to Europe of different alien species, while funding for research and management is often prioritised separately by the different Directorates-General in Brussels. The political, cultural and geographic complexity of Europe makes a single coordinating body a necessity”
The authors of the paper, who recently edited the Handbook of Alien Species in Europe*, recommend the European Parliament and Council give serious consideration to the establishment of a single body to bring together invasive species related resources and activities currently dispersed amongst the various European institutions. This body, which they call the European Centre for Invasive Species Management (ECISM), would have a mission to identify, assess and communicate current and emerging threats to the economy and environment posed by invasive species. ECISM would coordinate activities across Member States, building a Europe-wide surveillance system which could monitor emerging threats, support rapid response and raise public awareness around the issues of invasive species.
The idea is sound, but such a Centre would face considerable challenges. For example, the major policy driver of a single EU market for goods and people favours the spread of invasive species, the number of alien species introductions continues to increase year on year, and public awareness of the impact of those species is little more than 2%.
Unfortunately, these factors make the formation of such a body all the more challenging and only time will tell if Europe is able to meet that challenge.
* Daisie (2009)  Handbook of Alien Species in Europe. Springer, Dordrecht. ISBN 978-1-4020-8279-5

Significant Increase In Alien Plants In Europe Observed

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ScienceDaily (Sep. 18, 2008) The number of alien plant species has more than tripled over the last 25 years. This is the finding of a study by European scientists who evaluated the data from 48 European countries and regions.


Among the most widespread of the new plant species is the Canadian fleabane (Conyza canadensis), which originated in North America. (Credit: André Künzelmann/UFZ)
A total of 5789 plant species were classified as alien. Of these, 2843 originating outside of Europe, according to the researchers and their publication in the journal Preslia. By contrast, in 1980 only 1568 alien species were registered. Of these, 580 had come from outside Europe.
According to the researchers, around six new species arrive in Europe each year on average. This inventory of information about alien species is designed to help developing Europe-wide management strategies and tools of risk assessment to protect biodiversity. New species that bring about long-term changes to ecosystems by e.g. competing with native species, are regarded as one of the greatest threats to biodiversity.
The highest numbers of alien plant species were reported from Belgium, the UK and the Czech Republic. The UK, Germany and Belgium have the greatest numbers of naturalized aliens, new species that have been able to establish stable populations. Among the most widespread of the new plant species are Canadian fleabane (Conyza canadensis), Jerusalem artichoke (Helianthus tuberosus) and black locust or false acacia (Robinia pseudoacacia), which all originated in North America.
More than three-quarters of all new plant species have been brought to Europe unintentionally.
Not only can new plant species threaten the native flora, there can also be economic costs involved, as is the case with common ragweed (Ambrosia) for instance. Ragweed originated in North America and has already spread to large parts of Europe. Its pollen is one of the most aggressive allergens. Initial estimates for Germany put the annual costs associated with just three of the 470 most widespread neophytes at around € 70 million.
As part of the EU project DAISIE (Delivering Alien Invasive Species Inventories for Europe), all known alien species in the countries of Europe were documented for the first time. Information on the ecology and spread of alien plants and animals was collected and made available via an online database to anyone with an interest in the subject (http://www.europe-aliens.org/). Research institutes and organisations from 15 nations were involved in the project.

Invasions By Alien Plants Have Been Mapped In European Union

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ScienceDaily (Jan. 27, 2009)Biological invasions are one of the major threats to biodiversity and in many cases they have considerable impact on economy and human health. For their effective management it is important to understand which areas and ecosystems are at the highest risk of being invaded.


Giant Knotweed, an invasive species from the Far East Sakhalin Island, which threatens biodiversity of natural habitats in Europe. (Credit: Image courtesy of Milan Chytr)
The first map of the level of alien plant invasions in European Union was published in the Wiley-Blackwell journal Diversity and Distributions.
An international team of Czech, Spanish and British plant ecologists investigated species composition of vegetation in more than 50 000 sites in northwestern, southern and central Europe. In each of these sites they quantified the proportion of alien to native plant species.
“We found that the highest risk of alien plant invasions was in agricultural and urban ecosystems. Low levels of invasion were in natural and semi-natural grasslands and most woodlands, and the lowest levels in the Mediterranean evergreen vegetation, heathlands and peatlands. This pattern was quite consistent among European regions with contrasting climates, biogeography, history and socio-economic background”, said senior author Milan Chytrý from Masaryk University, Brno, Czech Republic.
“The level of plant invasions basically depends on the distribution of different ecosystem types across Europe. High levels of invasion are typical of lowland areas of western and central Europe while low levels are found in northern Europe and mountain regions across the continent. Low levels of invasion also occur in the Mediterranean region except its coastline and irrigated fields”, added Petr Pyšek from the Institute of Botany Pruhonice, Academy of Sciences of the Czech Republic.

2012/09/16

Climate Change Affecting Europe's Birds Now, Say Researchers

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ScienceDaily (Mar. 6, 2009)Climate change is already having a detectable impact on birds across Europe, says a Durham University and RSPB-led scientific team publishing their findings to create the world's first indicator of the climate change impacts on wildlife at a continental scale.


Lapwings Vanellus vanellus. (Credit: Copyright Jodie Randall/Royal Society for the Protection of Birds)
Published in the journal PLoS One, Durham University scientists working with the Royal Society for the Protection of Birds have shown a strong link between recent population changes of individual species and their projected future range changes, associated with climate change, among a number of widespread and common European birds, including the goldfinch and the lesser spotted woodpecker.
By pulling together Europe-wide monitoring data, the team has compiled an indicator showing how climate change is affecting wildlife across Europe. The European Union has adopted the indicator as an official measure of the impacts of climate change on the continent's wildlife; the first indicator of its kind.
The paper and the indicator were produced by a team of scientists from the RSPB, Durham University, Cambridge University, the European Bird Census Council, the Muséum National d'Histoire Naturelle, the Czech Society for Ornithology, and Statistics Netherlands. European population data for birds was compiled by The Pan-European Common Bird Monitoring Scheme (PECBMS), a partnership involving the European Bird Census Council (EBCC), the RSPB, BirdLife International, and Statistics Netherlands funded by the RSPB and the European Commission.
Dr Stephen Willis, of Durham University, said: "The impact of climatic changes, both positive and negative, can now be summarised in a single indicator which we've called the Climatic Impact Indicator. A period of stable annual average temperatures in Europe ended in the early 1980s, and this new Indicator shows that climate change is affecting many species but in different ways. Climate change is having an adverse effect on many birds, though some species are actually benefiting from the recent changes.
"Our indicator is the biodiversity equivalent of the FTSE index, only instead of summarising the changing fortunes of businesses, it summarises how biodiversity is changing due to climate change. Unlike the FTSE, which is currently at a six year low, the climate change index has been increasing each year since the mid-80s, indicating that climate is having an increasing impact on biodiversity.
"Those birds we predict should fare well under climate change have been increasing since the mid-80s, and those we predict should do badly have declined over the same period. The worry is that the declining group actually consists of 75 per cent of the species we studied."
The Climate Change Indicator combines two independent strands of work; bioclimate envelope-modelling and observed populations trends in European birds, derived from the Pan-European Common Bird Monitoring Scheme.
When a bird's population changes in line with the projection, the indicator goes up. Species whose observed trend does not fit the projection cause the indicator to decline.
The RSPB's Dr Richard Gregory said: "We hear a lot about climate change, but our paper shows that its effects are being felt right now. The results show the number of species being badly affected outnumbers the species that might benefit by three to one. Although we have only had a very small actual rise in global average temperature, it is staggering to realise how much change we are noticing in wildlife populations. If we don't take our foot off the gas now, our indicator shows there will be many much worse effects to come. We must keep global temperature rise below the two degree ceiling; anything above this will create global havoc."
The research shows that a number of species are projected to increase the populations across Europe. Of the 122 species that were surveyed, the top ten increasing species (in order) are: Sardinian warbler (P); subalpine warbler (P); bee-eater (P); cirl bunting (B); Cetti's warbler (B); hoopoe (P); golden oriole (B); goldfinch (B); great reed warbler (P); and collared dove (B). Species in this list marked with a (B) already breed regularly in the UK. Species marked with a (P) are potential colonists to the UK if they continue to respond to climatic warming in the way the models predict, and in the absence of other barriers (such as the ability to disperse and the availability of suitable habitat).
Of those species surveyed the worst performers across Europe (in order) are: snipe (B); meadow pipit (B); brambling (occasional B); willow tit (B); lapwing (B); thrush nightingale; wood warbler (B); nutcracker; northern wheatear (B); and lesser spotted woodpecker (B).
Of the 122 species included (out of 526 species which nest in Europe), 30 are projected to increase their range; while the remaining 92 species are anticipated to decrease their range.
Dr Gregory added: "This new work emphasises again the role played by skilled amateur birdwatchers right across Europe in advancing our understanding of the environment and the growing threat posed by climate change."

Bird Population Estimates Are Flawed, New Study Shows

ScienceDaily:


ScienceDaily (Nov. 29, 2008)Most of what we know about bird populations stems from surveys conducted by professional biologists and amateur birdwatchers, but new research from North Carolina State University shows that the data from those surveys may be seriously flawed – and proposes possible means to resolve the problem.


European robin. Researchers found that even small amounts of background noise, from rustling leaves or automobile traffic, led to a 40 percent decrease in the ability of observers to detect singing birds. (Credit: iStockphoto/Andrew Howe)
Bird populations are the focus of thousands of environmental research and monitoring programs around the world. A group of researchers led by NC State's Dr. Theodore Simons has been evaluating factors that confound estimates of bird abundance. For example, background noise can influence the ability of observers to detect birds on population surveys, and can result in underestimates of true population size.
In order to explore these questions, Simons and others worked to develop "Bird Radio:" a series of remotely controlled playback devices that can be used to accurately mimic a population of singing birds. Researchers could then control variables, such as background noise, to see whether it affected birdwatchers' ability to estimate bird populations.
The study found that even small amounts of background noise, from rustling leaves or automobile traffic, led to a 40 percent decrease in the ability of observers to detect singing birds. What's more, said Simons, "we also learned that misidentification rates increased with the number of individuals and species encountered by observers at a census point." In other words, the researchers found that traditional means of estimating the abundance and diversity of bird species are flawed due to complications such as background noise and the accuracy of the data observers collect on surveys of breeding birds.
But the Bird Radio research also points the way toward possible solutions. Simons explains that the Bird Radio findings are helping researchers develop better sampling methods and statistical models that will provide more accurate bird population estimates. For example, researchers are attempting to identify data collection methods that will help account for background noise or other outside factors in estimating bird populations.
The research, "Sources of Measurement Error, Misclassification Error, and Bias in Auditory Avian Point Count Data," is published in the upcoming book "Modeling Demographic Processes in Marked Populations Series: Environmental and Ecological Statistics, Vol. 3" (Springer, 2009). Simons, a professor of biology and forestry at NC State and an assistant unit leader of the U.S. Geological Survey's North Carolina Cooperative Fish & Wildlife Research Unit, was the lead author of the study. The research was co-authored by Dr. Kenneth H. Pollock, professor of biology and statistics at NC State; John M. Wettroth, an engineer with Maxim Integrated Products; Dr. Mathew W. Alldredge, who was a research associate at NC State; and Krishna Pacifici and Jerome Brewster, who were both graduate students in biology at NC State.

2012/09/06

Ecological Monitoring On Bird Populations in Europe Re-Evaluated

Iturria: Science Daily


ScienceDaily (Aug. 30, 2012)Biodiversity and environmental monitoring is of crucial importance to diagnose changes in the environment and natural populations in order to provide conservation practice with relevant data and recommendations. The information from monitoring is required, for example, for the design and evaluation of biodiversity policies, conservation management, land use decisions, and environmental protection.

Birds are headline indicators of biodiversity due to their worldwide distribution and popularity. More than 600 bird monitoring programs are in place in Europe, resulting in huge investment of effort. Nearly 28,000 people have been involved in the 144 monitoring programs analyzed in the Nature Conservation paper, spending almost 80,000 person days per year. The evaluation was performed in SCALES, a large-scale integrated project funded by the 7th Framework Program (FP7) of the European Union.
At a dedicated SCALES symposium at the 3rd European Congress of Conservation Biology (ECCB) in Glasgow on 28th-31st of August 2012, the lead author Dr Dirk Schmeller from the CNRS, France and guest researcher at the Helmholtz Centre for Environmental Research -- UFZ in Leipzig, Germany, commented: "Although popular among conservationists, bird-monitoring practices have never been characterized quantitatively. We undertook a focused questionnaire-based survey to objectively explore the strengths and weaknesses of the massive bird-monitoring effort in Europe. The results indicate a high potential for further improvements to bird monitoring in sampling design, data analysis and involvement of volunteers from the public."
"Variation in space and time can cause a significant deviation in the monitoring results, which may lead to incorrect conservation policy decisions," added Dr Klaus Henle from UFZ and coordinator of SCALES. "Therefore increasing awareness of the spatial or temporal scale at which monitoring has been performed can be of crucial importance!"
To optimize the monitoring practices, the scientists have proposed a range of recommendations. For most monitoring programs, the best data type to be collected is quantitative (count) data, such as number of individuals, which provide an early warning for conservation and policy. Further, monitoring could optimize resource allocation between independent monitoring sites. Importantly, even low variation between sites or years can induce spurious conclusions; hence repetitive sampling of the same sites within a year should be the rule.
In case of limited manpower, Schmeller and colleagues recommend an increase in the number of monitoring samples, even at the expense of the size of each sample. Further, more collaborations between monitoring programs at different scales need to be established, so that the sampled data may be integrated and re-used.
Finally, monitoring coordinators have to make special efforts to attract volunteers. Coordinators need to keep in mind several important points: 1) the specific characters of the local community; 2) having a recruitment strategy for volunteers interested in monitoring; 3) maintaining good communication with the volunteers; 4) having low hierarchies and treat volunteers with respect, and 5) making links to other voluntary organizations to add value to the work. Schmeller adds: "There is no one clear recipe to recruit and keep volunteers, but what is important is to keep in mind that the volunteers sacrifice their spare time for monitoring activities, which are of interest to all society!"

2012/09/05

For the Rooster, Size Matters: How Size of Hen's Comb Is Linked to Ability to Lay More Eggs

Iturria: Science daily


For the Rooster, Size Matters: How Size of Hen's Comb Is Linked to Ability to Lay More Eggs

ScienceDaily (Sep. 4, 2012) — A lone rooster sees a lot of all the hens in the flock, but the hen with the largest comb gets a bigger dose of sperm -- and thus more chicks. This sounds natural, but behind all this is humanity's hunger for eggs.


Three eighth generation advanced intercross siblings, demonstrating the extreme variation present in the cross. (Credit: Photo by Dominic Wright)
For thousands of years, people have tinkered with the development of domestic chickens. Through selective breeding for a few characteristics such as large muscle mass and increased egg-laying, we have at the same time caused numerous other radical changes in appearance and behaviour. A research group at Linköping University in Sweden has now shown how the size of a hen's comb is bound up with the ability to lay more eggs. The results have been presented in the scientific journal PLoS Genetics.
Compared with the original wild jungle hen, domestic hens have larger combs as well as denser bones. This influences egg-laying, as the hen's bone tissues provide calcium for the eggshells. The greater the bone mass, the more eggs she can lay.
After having spotted a clear correlation between comb size and bone mass in chickens from a cross between red junglefowl and domestic chicken, the research group -- under the leadership of evolutionary geneticist Dominic Wright -- set up a study where such chickens were crossed for several generations. In this way the genome was split up into smaller and smaller regions, which allowed the "mapping" of the functions of individual genes.
In the eighth generation, the researchers found an area that had a strong effect on the weight of the comb -- but also on bone mass and fertility.
The genetic variation has gradually decreased over the course of domestication. In domestic chickens there are now some 40 known small regions with stable genes that potentially govern their typical "domestic" characteristics. LiU researchers have now discovered two "pleiotropic" genes: two genes connected to each other that influence several characteristics simultaneously. By regulating the production of cartilage, they influence combs (which consist of cartilage throughout) as well as bone growth (where cartilage is the base material) and, ultimately, egg production.
"The original hens have smaller combs, thinner legs, and lay fewer eggs. When people bred for the characteristic of laying many eggs, the comb grew automatically," Dominic Wright says.
In nature, the comb is an example of a sexual ornament. Individuals -- often males -- with the most impressive ornaments are favoured by females, thereby obtaining more numerous offspring than their competitors. In domesticated animals, sexual selection -- like natural selection -- has lost its role, as it was humans who determine breeding.

2012/09/03

Can Blue Tits Can Save Our Conker Trees?

Iturria: Science Daily


Can Blue Tits Can Save Our Conker Trees?

ScienceDaily (Aug. 28, 2012) Blue tits, a familiar garden bird, could be the salvation of our imperiled conker trees (horse-chestnut trees, Aesculus hippocastaneus), which are under severe attack by a tiny non-native moth that has spread from continental Europe.


A blue tit in front of horse-chestnut leaves that are covered with brown patches of damage caused by the caterpillars of the leaf mining moths. (Credit: Richard Broughton/CEH)
Conker fans from across the country are being called upon to discover how many of the moth's caterpillars, hidden inside the leaves, are being discovered and preyed upon by birds.
The leaf-mining moth arrived in London just ten years ago, and has since spread across most of England and Wales. The moth caterpillars eat the leaves while hiding inside them, so damaging the leaves and causing them to turn brown and making the tree appear as if autumn has come early.
Experts at the NERC Centre for Ecology & Hydrology and the University of Hull are asking for the public's help to find out how many moth caterpillars are eaten by birds, such as blue tits. They are asking volunteers to check leaves from a horse chestnut tree for the distinctive damage caused by the birds to the leaf mines and report it through the Conker Tree Science website.
Dr Michael Pocock, from the NERC Centre for Ecology & Hydrology, said, "It's a big mission and we're reliant on people's help to discover how much birds are feeding on the alien moths."
"Excitingly, this mission was inspired by comments from some of the 8000 people who have taken part in previous Conker Tree Science missions. It's a great example of professional scientists and members of the public working together."
Dr Darren Evans from the University of Hull added, "The traditional game of conkers may be under threat, because trees infected with the alien moth produce smaller conkers. In discovering whether garden birds, like blue tits, can help to protect conker trees, we will also be learning more about the behaviour of the birds themselves."
The alien moth, which was discovered in the 1980s, has caterpillars that live inside the leaves, forming distinctive patches of damage called 'leaf mines'. Up to 700 leaf mines have been recorded on a single leaf and the damage caused by large numbers of larvae can be striking. A previous Conker Tree Science mission discovered that predatory wasps were not effectively controlling the alien moths, possibly explaining their rapid spread.
This project, where anyone can get involved with genuine scientific research, is one of the largest of its kind in the UK and is funded by the Natural Environment Research Council (NERC).
People can take part in the new 'Bird Attack' mission from 30th August 2012 to 23rd September 2012. More information: http://www.conkertreescience.org.uk/