Constantine Alexander's Journal: Avian

BirdLife International’s ‘Important Bird and Biodiversity Areas’ well covered by Natura 2000 in Europe but potential to extend network

EU networks of Special Protection Areas (SPAs, shown in orange) defined in the Birds Directive, and Important Bird and Biodiversity Areas (IBAs, shown in blue) identified by BirdLife International. Areas covered by both SPAs and IBAs are shown in green.

By Science for Environment Policy

The coverage of ‘Important Bird and Biodiversity Areas’ (IBAs) in relation to Special Protection Areas (SPAs) for birds in the EU has been assessed in a new study. Overall, 66% of the IBA network is covered by SPAs. SPAs were found to cover 23% of the distributions of 435 EU bird species as well as 25% of the distributions of mammals, reptiles and amphibians.

The European Union (EU) Birds Directive is one of the longest-established policy tools in bird conservation in Europe and aims to protect threatened wild, often migratory, bird species which occur naturally in the EU. Part of this protection involves the designation of key sites as Special Protection Areas. SPAs form part of the Natura 2000 network of protected sites along with Special Areas for Conservation (SACs) for other species and habitats designated under the Habitats Directive. Good implementation and management of Natura 2000 sites is a key part of the EU’s biodiversity strategy and the selection of sites has been a collaborative process between the European Commission (EC) and Member States.

BirdLife International, the world’s largest nature conservation partnership of 120 partners worldwide, has been working since the 1970s to identify and protect over 12,000 places of great significance for the conservation of the world’s birds; they have named these Important Bird and Biodiversity Areas (IBAs). In Europe, 20 criteria were used to identify IBAs of global, European and EU significance and the latter were selected specifically to qualify as SPAs.

The researchers identified a number of studies that supported the effectiveness of the Birds Directive and SPAs and yet others that suggested that current SPAs do not sufficiently cover particular species in the EU. They also acknowledge that in 2014, the EC received a mandate to deliver a ‘fitness check’ of the Birds and Habitats Directives as part of the its Regulatory Fitness and Performance program (REFIT), which is intended to simplify EU law. In light of the fact that international agreements, such as Target 11 of the Aichi Biodiversity Targets, also mean that protected areas are due to be expanded, the researchers aimed to identify the best areas to incorporate into an expanded SPA network to increase coverage of species efficiently.

This study analysed the overlap in coverage between land-based SPAs and IBAs and in relation to the distribution of bird, mammal, reptile and amphibian species (since birds have been shown to be effective indicators of wider biodiversity). Information on species distribution was obtained from distribution models for 435 birds (including 181 species on Annex I of the Birds Directive), 179 mammals, 138 reptiles and 85 amphibians. The models used habitat requirements, expert knowledge and known occurrence of species to produce high-resolution (300 m) maps of each species’ distribution. Species’ distribution could then be compared to the coverage of SPAs and IBAs, for different species groups as well as species in different IUCN Red List categories for threatened species. The researchers also assessed unprotected land that could be added to the SPA network, based on species occurrence and the location of current SPAs and IBAs.

The study found 3.307 IBAs cover 634.725 square kilometres (km²) or 14.5% of the EU, while 4.876 SPAs cover 534.006 km² or 12.5% of the EU. A total of 418.108km² of EU land is covered by both IBAs and SPAs, with 20.3% of IBAs falling almost completely (over 98%) within SPAs. In total, 66% of the IBA network is covered by SPAs. SPAs cover an average of 23% (almost 25% for IBAs) of the ranges of bird species and 25% (almost 28% for IBAs) of the ranges of mammals, reptiles and amphibians within the EU. When combined, the SPA and IBA networks cover 17.3% of the EU's land area and an average of 27.5% of the EU-wide distributions of bird species. However, 24.4% of IBAs fall almost exclusively outside (less than 2% within) SPAs.

The use of spatial tools to designate conservation areas for protection has become increasingly common. This study demonstrated that the EU’s land-based SPA network generally covers IBAs well. Researchers also found that IBAs covered the distribution of a relatively high number of mammals, reptiles and amphibians, supporting the idea that birds are useful proxies for the conservation of other species. The distribution of threatened species was also found to be slightly better covered by SPAs than non-threatened species. This may be partly due to threatened species having smaller ranges, which are better covered by the network. In practice, the researchers say that protected areas are an effective conservation tool for such species, whereas wider-ranging species, such as migratory birds, need more landscape-scale approaches.

The researchers also identified potential opportunities to expand the network. Adding just 4.5% of the EU land area to the SPA network (to meet Aichi Target 11 to protect 17% of land) would almost double bird species’ distributions from 22.9% to 40.4%. This expansion would also increase the coverage of mammal, reptile and amphibian species by up to 43%. The best locations for this expansion were primarily concentrated in the southern parts of the EU and near its northern and eastern borders.

The researchers point out that modelling approaches, such as the one used in this study, should not form the sole basis for the assessment of the effectiveness of the SPA network. Other measures such as species-specific population assessments should also be considered. Species distributions, which form the basis of this study, are also subject to errors if species have been lost from an area due to hunting, invasive species or habitat loss.

Overall, the researchers say that the network of SPAs informed by IBAs appears to provide a good coverage of species’ distributions, including those of non-bird species, which were not the original target of the designation. Small additions to the SPA network could also lead to big increases in species coverage, and site selection should be based on a rigorous scientific basis, the researchers say.

Citation: Kukkala, A.S., Santangeli, A., Butchart, S.H.M., Maiorano, L., Ramirez, I., Burfield, I.J. & Moilanen, A. (2016). Coverage of vertebrate species distributions by Important Bird and Biodiversity Areas and Special Protection Areas in the European Union. Biological Conservation. 202:1–9; DOI: 10. 106/j.biocon.2016.08.010.

Contact: Aija Kukkala

Posted at 04:22 AM in Avian, Environmental Politics, Science, Sustainable Development | Permalink | Comments (0)

High lead exposure for griffon vultures in Spain correlates with soil lead and ammunition from game hunting

Griffon vulture, Spain. Photo by Ted van den Bergh (CC 2.0)

By Science for Environment Policy

Maps of the risk of griffon vultures’ exposure to lead in north-eastern Spain have been produced in a new study. High-risk places are mountainous areas where there are high levels of bioavailable sources of lead in the soil, but also where game hunting is prevalent, and carcasses scavenged by the birds may contain lead ammunition.

Lead is a highly poisonous metal that at high exposure levels is fatal to people and wildlife and even at lower exposure levels can cause adverse health effects. For some wildlife populations, such as scavenging raptors, (birds of prey, such as vultures), lead ammunition in the carcasses of shot animals they eat is a major cause of lead poisoning.

In the European Union (EU), there is no harmonised legislation on lead in shot; different countries have different regulations governing the use of lead ammunition for hunting. For example, Denmark and the Netherlands have banned the use of lead shot for all hunting, and the use of lead ammunition is partly or fully banned in wetlands in 14 Member States. The European Commission has requested that the European Chemicals Agency (ECHA) assesses the risk of lead in ammunition to human health and the environment, along with the need for EU-wide action beyond any national measures already in place. They have also requested that the ECHA starts to collect information for the assessment of the risk and the socio-economic impact for any other uses of lead ammunition, including hunting in terrains other than wetlands, and target shooting, with a view to preparing, if necessary, another Annex XV dossier for restriction under the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) legislation¹.

This study investigated the exposure to lead of griffon vultures (Gyps fulvus) in north-eastern Spain. The study area covers almost 50 000 km² and around 21% of the Spanish and 15% of the European griffon vulture populations are found there. The area is characterised by intensive pig, poultry and rabbit farming in the plains, and cattle, goat and sheep farming and big-game hunting in the Pyrenees in the north and Iberian mountains in the south and west.

The threat from bovine spongiform encephalopathy (BSE), more commonly known as mad cow disease, has meant that farmers have to remove dead animals from their land that might otherwise have been eaten by the vultures. Conservation concerns for the birds resulted in the authorities setting up 50 feeding stations, which are commonly provided with dead livestock from the area.

To determine the vultures’ exposure to lead, the researchers measured lead concentrations in blood samples taken from 691 vultures, captured year-round at 25 feeding stations during the period 2008–2012. They considered the background concentration of lead in the blood from environmental sources — 200 nanograms of lead per millilitre of blood (ng/ml), according to literature. The researchers also measured the birds’ wing spans and weighed the birds.

The researchers found 310 (almost 45%) of the birds had levels of lead in the blood above the 200 ng/ml background level, 29 (less than 5%) of the vultures had clinically high blood-lead concentrations in the 500–1 000 ng/ml range and 10 (approximately 1.5%) of the vultures were exposed to potentially lethal lead concentrations greater than 1 000 ng/ml.

To trace the source of lead exposure, the researchers also analysed the composition of lead isotopes (different forms of lead atoms that vary in atomic mass) in the blood of 40 vultures. This analysis found that the signature of lead in the blood of birds with blood-lead levels more than 470 ng/ml was similar to the signature of lead found in lead ammunition sourced from different parts of the world.

Isotopic analysis also revealed that griffon vultures with blood-lead levels more than 470 ng/ml had isotope signatures that were consistent with lead from soil sources. Lead is more readily bioavailable in soils with high lead levels or with a low soil pH. Vultures might consume lead from the soil through lead in the grazing livestock they scavenge.

Using their results, the researchers modelled blood-lead concentrations for griffon vulture populations across the region and produced maps to illustrate the risks of lead exposure for the birds. These maps revealed that the highest risk of lead exposure above the 200 ng/ml threshold was in almost 18% of the region and concentrated in the north and central south-west mountain regions. These are the areas that have extensive game hunting. That these high-risk areas also contain soils that have naturally high lead levels and low soil pH is concerning, as point sources of lead from ammunition may add to the burden of lead in griffon vultures.

In contrast, the maps revealed that the plain areas where poultry, rabbits and pigs are intensively farmed had the lowest risk of lead exposure for the griffon vultures. The maps also highlighted that the highest risks occurred in winter, covering almost 44% of the area, where game hunting is particularly prevalent in autumn and winter months.

Griffon vultures are widely distributed apex species. They cover large distances when looking for carrion and eat carcasses, including those from hunting, which other species, such as the threatened Spanish imperial eagle Aquila adalberti, also eat. All these characteristics make griffon vultures useful as biomonitors of lead in the environment. Given their food is subsidised by livestock at feeding stations and hunting carcasses in the field, the researchers say they are particularly suited to identify potential risks to people who eat game meat.

The researchers say their maps can help managers to target high-risk areas and take suitable action, such as controlling the use of lead ammunition in these places to minimise exposure of wildlife and people to lead. The researchers further recommend that the presence of lead should be minimised (e.g. in hunting ammunition, mines, etc.) even in those areas where feeding stations have been established to conserve avian scavengers through the provision of alternative and safe food resources.

This study could be useful in the assessment of risks of lead in ammunition to human health and the environment, particularly in light of the ongoing assessment of the ECHA concerning possible REACH restrictions.

Request to the European Chemicals Agency to prepare restriction proposals conforming to the requirements of Annex XV to REACH

Citation: Mateo-Tomás, P., Olea, P.P., Jiménez-Moreno, M., Camarero, P.R., Sánchez-Barbudo, I.S., Rodríguez Martín-Doimeadios, R.C. & Mateo, R. (2016). Mapping the spatio-temporal risk of lead exposure in apex species for more effective mitigation. Proceedings of the Royal Society B, 283: 20160662. DOI:10.1098/rspb.2016.0662.

Posted at 06:21 AM in Avian, Environmental Disasters, Protected Areas, Science | Permalink | Comments (0)

Penguin population could drop 60 percent by end of the century

University of Delaware study shows temperature warming may have reached a tipping point.

University of Delaware researchers project that approximately 30 percent of current Adélie colonies may be in decline by 2060 and approximately 60 percent may be in decline by 2099. Warming in Antarctica, once beneficial to the penguins, has reached a tipping point and is causing the sharp decline. Credit: University of Delaware/ Megan Cimino.

Climate has influenced the distribution patterns of Adélie penguins across Antarctica for millions of years. The geologic record shows that as glaciers expanded and covered Adélie breeding habitats with ice, penguin colonies were abandoned. When the glaciers melted during warming periods, this warming positively affected the Adélie penguins, allowing them to return to their rocky breeding grounds. But now, University of Delaware scientists and colleagues report that this beneficial warming may have reached its tipping point.

In a paper published today (June 29) in Scientific Reports, the researchers project that approximately 30 percent of current Adélie colonies may be in decline by 2060 and approximately 60 percent may be in decline by 2099.

"It is only in recent decades that we know Adélie penguins population declines are associated with warming, which suggests that many regions of Antarctica have warmed too much and that further warming is no longer positive for the species," said the paper's lead author Megan Cimino, who earned her doctoral degree at UD in May.

Co-authors on the work include Matthew Oliver, principal investigator on the project and Patricia & Charles Robertson Professor of Marine Science & Policy in UD's College of Earth, Ocean, and Environment; Heather J. Lynch, assistant professor in the Department of Ecology and Evolution at Stony Brook University; and Vincent S. Saba, a research fishery biologist with the National Oceanic and Atmospheric Administration's National Marine Fisheries Service.

Declining populations

The Adélie penguin is a species that breeds around the entire Antarctic continent. The species is experiencing population declines along the West Antarctic Peninsula (WAP), which is one of the most rapidly warming places on Earth, while Adélie populations in other areas around the continent where the climate is stable or even cooling remain steady or increasing.

The researchers' objective was to understand the effects of climate change on Antarctic Adélie penguin colonies. The study builds on previously published work by Oliver's research team to better understand Antarctica's shifting ecosystem by tracking penguins and their habitats. The current work used satellite data and global climate model projections to understand current and future population trends on a continental scale.

"Our study used massive amounts of data to run habitat suitability models. From other studies that used actual ground counts--people going and physically counting penguins-- and from high resolution satellite imagery, we have global estimates of Adélie penguin breeding locations, meaning where they are present and where they are absent, throughout the entire Southern Ocean. We also have estimates of population size and how their populations have changed over last few decades," explained Cimino, now a postdoctoral scholar at Scripps Institute of Oceanography.

"When we combined this data with satellite information and future climate projections on sea surface temperature and sea ice, we can look at past and future changes in Adélie penguin habitat suitability," Cimino said.

Funded through the NASA Biodiversity program, the study is based on satellite observations from 1981-2010 of sea surface temperature, sea ice and bare rock locations, and true presence-absence data of penguin population estimates from satellite imagery.

In particular, the researchers examined the number of years from 1981-2010 with novel or unusual climate during the Adélie penguin chick-rearing period from past satellite observations and used an ensemble of global climate models to make predictions about Adélie penguin habitat suitability from 2011-2099. The team validated the models with documented population trends.

The study results suggest that climate novelty, particularly warm sea surface temperature (SST), is detrimental to Adélie penguins. While the specific mechanisms for this relationship remain unknown, the study focuses attention on areas where climate change is likely to create a high frequency of unsuitable conditions during the 21st century.

Lynch noted that "One of the key advances over the last decade is our ability to find penguin colonies from space and, nearly as important, to determine which areas of Antarctica do not support penguin colonies. Having both true presence and absence across a species' global range is unique to this system, and opens up new avenues for modeling habitat suitability."

Refugia offer a glimmer of hope

According to Cimino, the southern WAP, associated islands and northern WAP regions, which are already experiencing population declines, are projected to experience the greatest frequency of novel climate this century due to warm SST. This suggests that warm sea surface temperatures may cause a decrease in the suitability of chick-rearing habitats at northerly latitudes.

"Matt and I have worked extensively at Palmer Station and we know that penguin colonies near there have declined by at least 80 percent since the 1970s. Within this region we saw the most novel climate years compared to the rest of the continent. This means the most years with warmer than normal sea surface temperature. These two things seem to be happening in the WAP at a higher rate than in other areas during the same time period," Cimino said.

By contrast, the study also suggests several refugia -- areas of relatively unaltered climate -- may exist in continental Antarctica beyond 2099, which would buffer a species-wide decline. Understanding how these refugia operate is critical to understanding the future of this species.

"The Cape Adare region of the Ross Sea is home to the earliest known penguin occupation and has the largest known Adélie penguin rookery in the world. Though the climate there is expected to warm a bit, it looks like it could be a refugia in the future, and if you look back over geologic time it was likely a refuge in the past," Cimino said.

The researchers reported that climate change impacts on penguins in the Antarctic will likely be highly site specific based on regional climate trends, and that a southward contraction in the range of Adélie penguins is likely over the next century.

"Studies like this are important because they focus our attention on areas where a species is most vulnerable to change," concluded Cimino. "The results can be used for management; they can have implications for other species that live in the area and for other ecosystem processes."

Citation: Megan A. Cimino, Heather J. Lynch, Vincent S. Saba and Matthew J. Oliver; Projected asymmetric response of Adélie penguins to Antarctic climate change; Scientific Reports, 2016; 6: 28785; DOI: 10.1038/srep28785.

Contact: Peter Bothum
University of Delaware

Posted at 03:45 AM in Avian, Biodiversity, Climate Change, Science | Permalink | Comments (0)

Shifting bird distribution indicates a changing Arctic

A male Spectacled Eider wears a surgically implanted satellite transmitter after its release in northern Alaska. Credit: USGS.

Shifts in the distribution of Spectacled Eiders, a predatory bird at the top of the Bering Sea's benthic food web, indicate possible changes in the Arctic's marine ecosystem, according to new research in The Condor: Ornithological Applications.

Matt Sexson of the USGS Alaska Science Center and his colleagues compared recent satellite telemetry data from molting eiders with data from the mid-1990s. They found that in two of the species' four primary molting areas, the birds have shifted their range significantly in the intervening decades, and the researchers interpret this as an indicator of ecosystem change--eiders go where their prey is, and their movements could indicate big changes in the community of bottom-dwelling, cold-water-dependent invertebrates they eat.

It's easier to track marine predators than it is to track their prey, explains Sexson. "It's tough to speculate on the connection with climate change because the data are so sparse, but we know that the north Pacific is changing," he says. "There's a lot of corresponding evidence that together all says something big is happening here, and eiders provide a readily available indicator that changes are occurring."

Sexson and his colleagues spent months at a time in the remote Arctic to catch eiders on land during their breeding season, luring them into nets before making a two-hour trek back to base camp with each bird to surgically implant a satellite transmitter. "It's a lot of hard work, but it's a lot of fun," Sexson says. "I used to just flip past the eiders in bird field guides, thinking I'd never see any of these. Now five years later I'm catching them and holding them. I've really developed a love for this group of birds--how unique they are, how beautiful they are. I've just become attached."

According to the University of Maryland's Jackie Grebmeier, an expert on Arctic marine ecosystems who was not involved with the new study, "The results of this research provide an important finding of biological response of an upper-trophic-level seabird to climate warming and sea ice retreat, another piece in the puzzle to address ecosystem change in the Pacific Arctic region." As Arctic water warms, whole communities of animals are moving north--and there's only so far they can go.

Citation: Matthew G. Sexson, Margaret R. Petersen, Greg A. Breed, and Abby N. Powell; Shifts in the distribution of molting Spectacled Eiders (Somateria fischeri) indicate ecosystem change in the Arctic; The Condor (August 2016), Vol. 118, No. 3, pp. 463-476; DOI: 10.1650/CONDOR-15-139.1.

Contact: Rebecca Heisman
Central Ornithology Publication Office

Posted at 03:45 AM in Avian, Biodiversity, Climate Change, Environment, Science | Permalink | Comments (0)

How did cardinals get those bright red feathers?

Researchers find gene responsible for red color in birds

Cardinal. Photo by Vicki Lackey (CC 2.0)

For many birds, just like for many people, red is the color of love. And, as with so many things, there is science behind the color. Researchers at Washington University School of Medicine in St. Louis and colleagues have discovered the gene that produces the brilliant red color in male birds that is so attractive to females.

The researchers found an enzyme that they suspect converts a yellow molecule, which the birds obtain by eating seeds, leaves and fruit, into a red one. This enzyme is active in the eyes of red and yellow birds, where it plays a role in their ability to see color. But in red birds, the enzyme is also active in the skin and feathers. The study was published on May 19 in Current Biology.

"In many bird species, the redder the male, the more successful it is at finding mates," said the study's co-senior author Joseph Corbo, MD, PhD, an associate professor of pathology and immunology at Washington University. The research was conducted by Corbo's team and scientists at the University of Auburn in Alabama and the University of Porto in Vairão, Portugal. The Portuguese team, led by Miguel Carneiro, PhD, initiated the project.

"Nobody knows for sure why red color is associated with reproductive success," Corbo added. "We thought that if we could figure out how they produced that red color, that would help us understand the advantage to being red."

The yellow and red colors in bird feathers are created by organic pigments known as carotenoids. Birds obtain yellow carotenoids from their diet. The scientists focused on a bird called the red factor canary to study the origin of red coloration. The bird originated in the early 20th century when commercial breeders crossed a wild South American bird called the red siskin with the common yellow canary. The breeders selected the reddest offspring and bred them to canaries again. In this way, over several generations, they created a bird that looked like a canary but was red.

The scientists expected that, after so many generations of crossbreeding with yellow canaries, the DNA of the red factor canaries would be derived almost entirely from their canary ancestors, except for the DNA areas related to coloration, which would have come from the red siskin side. The researchers compared the genomes of the red factor canary, the red siskin and the yellow canary and found differences in two regions of the genomes. One region contained a gene for an enzyme that is thought to trigger the conversion of the yellow carotenoid into a red one. Corbo and colleagues showed that the gene CYP2J19 was turned on in the skin of red factor canaries, but not in the skin of those that were yellow. The other region contained a gene involved in the growth of feathers and skin.

"It seems that, for a bird to grow red feathers, it needs not just the redness gene but also a special form of the gene involved in feather growth," Corbo said. "But how the redness gene and the feather growth gene work together to enable red feather coloration is unknown."

The redness gene is not unique to red birds; yellow canaries and other birds also carry it. The difference between red and yellow birds is not in the gene itself - Corbo and his colleagues sequenced the gene in red factor and yellow canaries and found no important differences - but in which parts of the body the gene is turned on. In yellow canaries, the gene is turned on only in the eyes, where it is thought to create red molecules that act as a light filter and help the birds see color. In red birds, it is turned on in the skin, feathers and liver, in addition to the eye. Since the gene is widespread in birds, many birds may have the potential to have red feathers. However, if the gene isn't turned on in their skin, they don't get the benefit of scarlet plumage.

"There are whole groups of bird species in which the ancestral bird was yellow and most of the daughter species are yellow, too, but here and there you find a red species," said Corbo, who is also an associate professor of genetics and of ophthalmology and visual science. "It suggests that somewhere along the line that red gene got turned on in the skin, and then it spread throughout the species, maybe by sexual selection."

The next step is to track down the stretches of DNA responsible for turning on CYP2J19 in the skin of red birds but not yellow ones. To do so, Corbo, a St. Louis Cardinals fan, is on the trail of the rare yellow cardinal.

"Every once in a while, a yellow cardinal is spotted in the wild," he said. "We hypothesize that this is a rare mutant that is unable to produce the red carotenoid. If we find that yellow cardinals have a mutation in CYP2J19 or its regulatory elements, that would provide even more evidence that this gene is important in red coloration. We've got a tiny piece of tissue from a museum specimen, and we're looking for a mutation now."

Citation: Ricardo J. Lopes, James D. Johnson, Matthew B. Toomey, Mafalda S. Ferreira, Pedro M. Araujo, José Melo-Ferreira, Leif Andersson, Geoffrey E. Hill, Joseph C. Corbo, Miguel Carneiro; Genetic Basis for Red Coloration in Birds; Current Biology (May 19, 2016); DOI: 10.1016/j.cub.2016.03.076.

Contact: Judy Martin-Finch
Washington University School of Medicine

Posted at 06:02 AM in Avian, Biodiversity, Science | Permalink | Comments (0)

Uncovering the secrets of Arctic seabird colonies

Nearly two million seabirds nest along the Norwegian coast north of the Arctic Circle. How do they decide where to nest?

More than a million puffins nest in colonies on the coasts of the Norwegian and Barents Sea. Their nesting colonies are located in areas where currents and coastal features concentrate prey. Photo by Per Harald Olsen, NTNU.

Ninety per cent of Norway's two million pairs of cliff-nesting seabirds are located in nesting colonies above the Arctic Circle.

But why are these colonies located exactly where they are? Much of the 1200-km stretch of coastline from the Arctic Circle to Norway's easternmost point, on the Russian border, has features that ought to be attractive to birds that nest in colonies, mainly steep, protected cliffs that are essentially inaccessible to terrestrial predators.

Using computer models to describe ocean currents and the transport of floating fish larvae, researchers were able to show that bird colonies are located in areas where currents and the shape of the coastline cause fish larvae to concentrate.

More simply stated, "the birds are where the food is," said Hanno Sandvik, a biologist from the Centre for Biodiversity Dynamics at the Norwegian University of Science and Technology (NTNU) and first author of a paper published in Nature Communications on Friday.

This may seem like a self-evident fact, but the research team is the first ever to be able to essentially predict where seabird colonies should be, based on fish larvae "hot spots" that show up in computer models of how fish larvae are transported along the coast.

"We are starting from where the prey is," Sandvik said. "We know where the prey is (because of the computer models). Then, based on what we know about where their prey is, where should the colonies be?"

Spotting a pattern in hot spots

The idea for the study came about several years ago, when researchers met to discuss a different project for which oceanographers from the Norwegian Institute of Marine Research (IMR) had created a coastal current and fish larvae transport model.

By using wind, water temperature and salinity information that has been collected by the Norwegian Meteorological Institute for decades, the oceanographers could calculate the strength and direction of currents along the Norwegian coast, and could simulate how fish larvae and plankton, which float with the current, would be transported.

The IMR researchers showed the assembled group of researchers a series of PowerPoint slides of the northern Norwegian coast with fish larvae concentrations mapped along the coastline over a number of years. They used red to show the densest concentrations, which meant that fish larvae "hot spots" were highlighted in red.

Although currents transport larvae and plankton along the entire coast, these floating organisms are not uniformly spread along the coastline. That's because of the way the current interacts with different coastal features, which concentrate organisms in the eddies that form along banks, islets and promontories.

After Robert Barrett, a biologist from the Department of Natural Sciences at the Tromsø University Museum, saw several of the slides, he realized that the red "hot spots" were in exactly the same place every year, and their location neatly predicted seabird colony locations.

"I said, 'Hang on! Let's have a look at that,'" said Barrett, who is also the second author on the paper. "Those red concentration dots are distributed exactly where the seabird colonies are."

It was then that the researchers decided to develop a statistical test to see if northern Norway seabird colonies are in fact closely associated with areas along the coast where currents concentrate food.

"We had been discussing for a long time why seabird colonies are where they are," Barrett said. "Here the IMR researchers were showing us models of fish larval concentrations, and it fit. The food, of course, is totally dependent on ocean currents, climate and topography. It turns out that yes, there are hot spots along the coast where food is concentrated. And this is what the seabirds have tuned into long, long ago."

Timing, stability important

For the research presented in the Nature Communications article, the IMR oceanographers simulated what the fish larvae and plankton concentrations would have looked like along the northern Norwegian coast each year from 1982 to 2011, or for 30 years. Sandvik and his other colleagues then combined this with seabird population numbers collected by the Norwegian Institute for Nature Research to see what kinds of patterns emerged.

So, for example, it is well known that July, which is relatively late in season for nesting seabirds, is a very important month when it comes to parents feeding their chicks. The chicks are nearly ready to leave the nest, so they are quite large and need a lot of food. That means the parents are working overtime to feed them.

Because of this demand, high fish larvae concentrations in July were among the most strongly associated factors with the presence of a nesting colony.

Sandvik also found that colony locations were strongly associated with locations where fish larvae concentrations had a high minimum level across many years. If an area along the coast had very high levels of fish larvae concentrations, but if those levels were not consistent over the years, then a colony was less likely to be associated with that spot.

"Birds prefer places where the (prey) numbers are as stable as possible," Sandvik said. "The best places are where you have enough fish larvae every year."

This makes sense from a biological standpoint because seabirds can't suddenly change their reproductive abilities from year to year--they can't lay 10 eggs in a good year and one egg in a bad year. So the birds simply can't take advantage of years when there is a lot of prey in the ocean.

But if prey is available nearly every year at the minimum level needed for birds to reproduce successfully, that is much more attractive to seabirds -- and the research backs this up.

The location of seabird colonies along the northern Norwegian coast is strongly controlled by fish larvae and plankton 'hot spots,' where currents and the contours of the coast concentrate food for the birds. Photo by Per Harald Olsen, NTNU.

Lofoten key, stable source of cod

One other surprising finding was the importance of cod larvae that originate from spawning grounds in the Lofoten Islands, Sandvik said.

The two currents that are responsible for moving water along the northern Norwegian coast move north and then east, wrapping around the top of Norway near Hammerfest and heading east towards Kirkenes. These currents thus bring cod larvae north from spawning grounds and then east along the coastline.

If Sandvik looked just at concentrations of herring larvae, there was no significant association between herring and colony location. But if he looked at cod larvae, the association between larvae concentrations and colony location was highly significant, he said.

The Lofoten area has continually exported dried cod since the Viking times, 900 years ago, which suggests that the cod spawning area there has been stable over long periods, Sandvik said. That means it's possible that the location of the seabird colonies in northern Norway might have persisted for centuries, if not longer.

"It really seems to be the area that is driving this entire system," he said.

Citation: Hanno Sandvik, Robert T. Barrett, Kjell Einar Erikstad, Mari S. Myksvoll, Frode Vikebø, Nigel G. Yoccoz, Tycho Anker-Nilssen, Svein-Håkon Lorentsen, Tone K. Reiertsen, Jofrid Skarðhamar, Mette Skern-Mauritzen and Geir Helge Systad; Modelled drift patterns of fish larvae link coastal morphology to seabird colony distribution; Nature Communications, 2016; 7: 11599; DOI: 10.1038/ncomms11599.

Contact: Hanno Sandvik
Norwegian University of Science and Technology

Posted at 03:25 AM in Avian, Biodiversity, Marine Environment, Science, Travel | Permalink | Comments (0)

Shrinking shorebird pays the bill for rapid Arctic warming while wintering in the tropics

Red knots used to incubate their eggs in the Arctic snow in order to optimally time the hatch date of their chicks relative to the insect food peak. Nowadays, red knots have a hard time keeping pace with the rapidly advancing onset of Arctic summer. Photo: © Jan van de Kam

Red knots migrate between their breeding grounds in the Arctic and their wintering grounds in West Africa. Chicks currently born under rapidly warming conditions attain smaller sizes before migration starts, because they miss the insect peak. If they reach their wintering grounds in the tropics, they are faced with a second disadvantage: their shorter bills cannot reach their favourite shellfish food. This results in an evolutionary force towards smaller-sized birds with large bills.

These findings will be published Friday 13 May 2016 in Science by an international team of researchers from the Netherlands (NIOZ and Univ. Groningen), Australia (Deakin Univ.), France (CNRS), Poland (Univ. Gdansk), and Russia (Moscow Univ.).

Climate change makes animals smaller

Shrinkage of animal body size has just recently been discovered, but is already considered a universal response to climate change as it is observed across a broad range of animal taxa. Up to now, two competing hypotheses explain the reduction in animal body size. On the one hand, there is the hypothesis that a smaller body is better able to dissipate body heat because of the larger surface to volume ratio. On the other hand, there is the hypothesis that bodies are shrinking because climate change disrupts the ability of a consumer to find enough of the right food at the right time, leading to malnutrition during the juvenile life stage.

Only long-billed red knots are able to access the deeply burrowed bivalves at their tropical wintering grounds. Shorter-billed birds are forced to make a living of shallowly burrowed seagrass rhizomes. Photo: © Jan van de Kam

Arctic animals shrinking fastest?

As the High Arctic is warming up most rapidly, body shrinkage is expected to be most extreme in this region. However, many organisms breeding in the High Arctic are long-distance migrants, spending the nonbreeding season at much lower latitudes, often as far as the tropics, where the impacts of climate change are less obvious.

First author Jan van Gils from NIOZ Royal Netherlands Institute for Sea Research explains: "The red knot (Calidris canutus canutus) is one of the world's most northerly breeding birds and a well-known long-distance migrant. It is nesting in northern Taimyr (Russia) and is wintering in tropical coastal ecosystems, notably the Banc d'Arguin, Mauritania (West Africa). Analysis of satellite images has shown that over the past 33 years, snow at the red knot's breeding grounds has progressively melted earlier, at a rate of half a day per year, so that's now more than two weeks. The retreat of the snow marks the start of the insect peak in the Arctic (Fig. 1); the main food source of the chicks before they leave the Arctic. Juvenile red knots that we caught along the Baltic coast while on their way to West Africa were smaller and had shorter bills after warm Arctic summers".

Shrinking migrants pay the bill in the tropics

Once they have arrived in West Africa, the smallest young birds pay the price of having a short bill: their survival was only half of that of the larger juveniles. Van Gils: "The reason for this bill-length dependent mortality is quite straightforward. Only larger birds with long bill were able to reach the relatively deeply burrowed bivalves at Banc d'Arguin (Fig. 2). Shorter-billed birds were forced to live on seagrass, which is a poor food source for these birds. The poor survival of shrunken first-year birds clearly contributes to the current population decline seen in red knots nowadays".

The red knot as it is now (left) and an (exaggerated) projection how the future red knot might look like (right): smaller, but having maintained its relatively long bill. Photo: © Jan van de Kam

Not only body size, but also body shape changes

The high premium on having a long bill, causes red knots also to change body shape (Fig. 3). Nowadays red knots are smaller, but since the short-billed small birds are selected against, the ones with the highest survival chances are relatively long-billed.

Van Gils concludes: "Since smaller birds do worse than larger ones, we reject the hypothesis that body shrinkage is evolutionarily beneficial. Instead, we suggest that a so-called 'trophic mismatch' during chick stage underlies the smaller knot body: due to the rapidly advancing Arctic summer, juvenile knots are now simply born after the rapidly advancing insect peak. We therefore propose that changes in body size and shape, and the negative population dynamical consequences, will be widespread among other High-Arctic breeding species in the future. This is a very serious ecological effect that requires our immediate attention".

Citation: van Gils, J.A., Lisovski, S., Lok, T., Meissner, W., Ożarowska, A., de Fouw, J., Rakhimberdiev, E., Soloviev, M.Y., Piersma and T. & M. Klaassen; Body shrinkage due to Arctic warming reduces red knot fitness in tropical wintering range; Science (13 May 2016) 352 (6287); DOI: 10.1126/science.aad6351.

Contact: Jan van Gils
NIOZ Royal Netherlands Institute for Sea Research

Posted at 02:27 AM in Avian, Biodiversity, Climate Change, Marine Environment, Science | Permalink | Comments (0)

Why vultures matter and what we lose if they're gone

Evan R. Buechley releases an adult Egyptian Vulture in Armenia after tagging it with a satellite tracking device (visible on the back of the bird). This device will allow detailed tracking of the movements in order to investigate where this endangered species is breeding, feeding, and migrating. Such technology is important for identifying critical habitat for the conservation of endangered vultures. Photo Credit: Anush Khachatrian.

Vultures. Cartoon characters in parched deserts often wish them to disappear, since circling vultures are a stereotypical harbinger of death. But, joking aside, vultures in some parts of the world are in danger of disappearing. And according to a new report from University of Utah biologists, such a loss would have serious consequences for ecosystems and human populations alike.

The primary threat to vultures, according to the report published today in Biological Conservation, is the presence of toxins in the carrion they consume. On many continents, vultures are the unfortunate victims of poisoned carcasses -- especially impactful because dozens -- or even hundreds -- of vultures can feast on a single carcass. Populations of most vulture species around the world are now either declining or on the brink of extinction.

Losses of vultures can allow other scavengers to flourish, according to biologists Evan Buechley and Çağan Şekercioğlu. Proliferation of such scavengers could bring bacteria and viruses from carcasses into human cities.

An adult Hooded Vulture in Ethiopia is shown. The once common Hooded Vulture was uplisted to critically endangered in 2015 because of drastic declines in populations across Africa. Hooded vultures are dying primarily from poisons in the carrion they eat. Photo Credit: Evan R. Buechley.

Risk factors for decline

In 2004, Şekercioğlu published a study examining the respective extinction risks of all bird species throughout the world. He noted then that vultures represented the single most threatened group of birds. Now, more than a decade later, Buechley and ?ekercio?lu have examined factors affecting the extinction risk of more than 100 bird species, including 22 species of vultures, which eat carrion exclusively, and other scavenging birds that have broader diets.

Their results suggest several inherent ecological traits that likely contribute to vultures' extinction risk, including their large body masses, slow reproductive rates and highly specialized diets. The greatest external threat to vultures, however, is poisoning.

Poisoning on three continents

Poisoning is the greatest extinction risk facing vultures, and impacts 88 percent of threatened vulture species. The poisons come in many forms.

In North America, the California condor, a vulture, experienced sharp declines until only 22 individuals remained by 1982. The leading cause of decline? Toxic lead bullet fragments in the gut piles left behind by hunters after animals had been field-dressed. Intensive conservation efforts helped the species to rebound. The condors now number well over 400, and range over large areas of California, Arizona, Utah and Baja California, Mexico.

In the mid-1990s India experienced a precipitous vulture decline, with more than 95 percent of vultures disappearing by the early 2000s. "That was a massive collapse that led a lot of people to really focus more attention on vultures," Buechley says. The cause was eventually traced to diclofenac, a veterinary anti-inflammatory drug that relieved pain in cattle, but proved highly toxic to vultures. Hundreds of vultures would flock to each cattle carcass. And if the cow had recently been treated with diclofenac, hundreds of vultures would die. Because of this highly gregarious feeding behavior, less than one percent of cattle carcasses contaminated with diclofenac could account for the steep vulture decline. Fortunately, international cooperation led to a total ban on veterinary diclofenac use. Buechley says the numbers of vultures have stabilized, and are now showing signs of slowly increasing.

Now, the center of the vulture crisis is in sub-Saharan Africa. "In Africa, it's a lot more challenging," Buechley says. "It's a darker story." Potent newly affordable poisons are used to control predatory pests, such as lions or jackals. The poisons are so toxic that they can cascade through ecosystems: birds, mammals and insects are often found littering the area around these poisoned carcasses. But, as the predominant scavenger, vultures take the brunt of the poisoning and face the largest number of casualties. For example, an elephant carcass poisoned in Namibia in 2007 killed as many as 600 vultures. In other cases, vultures are the victims of poachers who poison carcasses so that vultures do not give away the location of illegally taken animals. "Vultures are taking the hit, indirectly, for a lot of this human-wildlife conflict, as well as the illegal trade in animal parts," Buechley says. This crisis, unfortunately, is ongoing.

An adult critically endangered California Condor that was released into the wild in the Grand Canyon region of Arizona. California Condor populations are recovering across North America with extensive conservation efforts after reaching a population low of only 22 individuals in the 1980’s. Photo credit: Evan R. Buechley.

Rise of the facultative scavengers

In vultures' absence, other scavenger populations increase to take advantage of all of the uneaten carrion. By some estimates, in Central America, South America and Africa, vultures eat more meat than all predators combined. Without vultures, animals that eat carrion as a part of their diet (called facultative scavengers, as opposed to vultures, which eat only carrion) proliferate to take advantage of the available nutrients in a dead carcass. "There are a ton of nutrients in carrion that are going to be taken advantage of by something," Buechley says.

Crows, rats, dogs -- any of these species can suddenly become abundant and dominant, to the point of crowding out the remaining vultures. Hundreds of vultures on a carcass can easily frighten away packs of dogs, Şekercioğlu says. But when only a few vultures are left, the dogs can rule.

Such changes in populations of certain animal groups can upset the balance of food webs. "All these facultative scavengers are also predators, and so they also go out and eat other organisms too," Buechley says. "You have this cascading effect."

Human impacts

The impact of vultures' declines are not limited to the realm of ecology, however. Vultures are highly efficient consumers of carrion, sometimes locating and consuming carcasses within an hour, before other forms of decay can set in. And vultures' stomachs are highly acidic, killing nearly all bacteria or viruses that may be present in carrion. Combined with the fact that vultures rarely come in contact with humans, vultures serve as a barrier to prevent diseases from proliferating in dead animals and spreading to humans. Other facultative scavengers are not so adapted, and could pass along those diseases into human populations, as many are already fixtures in cities. For example, following the decline of vultures, India experienced a strong uptick in feral dogs --by an estimated seven million. The increase in dogs, potentially feeding on disease-ridden carcasses, is thought to have at least partially caused the rabies outbreak that was estimated to have killed 48,000 people from 1992-2006 in India -- deaths that may have been avoided if not for the disappearance of vultures.

Members of the Parsi sect of Zoroastrianism experienced a different impact. For thousands of years, the Parsi people have placed their dead on exposed mountaintops or tall towers for vultures to consume. The practice is called "sky burial."

But with few vultures and unable to properly handle their dead, the Parsis experienced a crisis within the faith. Some constructed captive vulture aviaries. Others talked about desiccating bodies using focused solar mirrors. The Parsis' plight exemplifies the vultures' role in south Asian society -- and the various impacts if the vultures aren't there.

At a road-kill dog carcass in Ethiopia, a Bearded Vulture, the only vertebrate osteophage (bone-eating specialist), swallows a large section of dog vertebrae whole. Photo credit: Evan R. Buechley

Learning from the past

Although the vulture crisis in Africa is ongoing, Buechley and Şekercioğlu can predict what the outcome will be, based on previous experiences in India. Crows, gulls, rats and dogs will boom. And the rabies outbreak in India may just be a prologue, because several sub-Saharan Africa countries already have the highest per-capita rabies infection rates in the world. Rabies is only one of the many potential diseases that vultures had helped regulate.

Buechley notes that the poisoning that is killing vultures is also affecting many other organisms throughout ecosystems. But vultures are the most sensitive canaries in ecological coal mines. The story of the California condor shows that recovery is possible, but at a high cost that countries in the developing world may not be able to pay.

"It's good news and bad news," Şekercioğlu says. "It shows that we can bring back these scavengers. But the bad news is that once we get to these numbers, it costs tens of millions of dollars and decades to bring them back. You don't want to go there. And once you go there, we can afford to save only a few species."

So, Buechley argues, "the better solution is to invest in vulture conservation here and now, in order to stem incalculable damage from trophic cascades and increased human disease burden in the developing world."

Citation: Evan R. Buechley and Çağan H. Şekercioğlu; The avian scavenger crisis: Looming extinctions, trophic cascades, and loss of critical ecosystem functions; Biological Conservation, 2016; 198: 220; DOI: 10.1016/j.biocon.2016.04.001.

Contact: Paul Gabrielsen
University of Utah

Posted at 05:38 AM in Avian, Biodiversity, Environmental Disasters, Science, Sustainable Development | Permalink | Comments (0)

New studies highlight energy development's impact on birds

Sandhill Cranes fly in close proximity to wind turbines near Horicon National Wildlife Refuge in east-central Wisconsin, but to date no crane mortality has been associated with turbines in this area. Credit: USGS.

The ornithology journal The Condor is publishing a Special Section of open access articles highlighting the impact that energy development is having on North America's bird populations.

"Although renewable energy may offer a 'greener alternative' to traditional energy sources, mounting evidence suggests that renewable energy infrastructure and the power transmission lines needed to serve them may impact avian populations," according to lead editor Jennifer Smith, a post-doctoral research associate at the Virginia Polytechnic Institute & State University. "Most avian-energy research has focused historically on direct effects of avian collision or electrocution with overhead power systems, and more recently on avian collisions at wind energy facilities. While research has expanded to consider indirect effects, large gaps in our knowledge persist."

The editors behind the Special Section hope to address these gaps by increasing our understanding of avian interactions with renewable energy infrastructures and identifying areas for future research. The collection of papers was inspired by symposia hosted at the 2014 joint meeting of the American Ornithologists' Union, the Cooper Ornithological Society, and the Society of Canadian Ornithologists, and at the 2014 meeting of the Raptor Research Foundation. Topics addressed include:

How wind energy infrastructure is impacting the reproductive success of Horned Larks and McCown's Longspurs in Wyoming
The effects of oil and gas development in Alberta and the Northwest Territories on Canada's boreal birds
Whether wind towers in the Great Plains region pose a risk to wintering Sandhill Cranes
How migrating raptors alter their flight behavior in response to power line construction
How energy development stacks up against other manmade threats to birds

"Birds have complex interactions with energy infrastructure. The diverse papers in this Special Section evaluate threats that manifest themselves in different ways across species, landscapes, and types of infrastructure," says Condor Editor-in-Chief Phil Stouffer. "With the expected trajectory of energy development, particularly renewable resources, it will become increasingly important to manage risks to wildlife. We hope ornithologists can inform decisions about energy development using information like we're publishing here."

The six open access papers comprising the Special Section will be published April 20, 2016, and will be available at this website.

Contact: Rebecca Heisman
Central Ornithology Publication Office

Posted at 04:07 AM in Avian, Renewable Energy, Science | Permalink | Comments (0)

Botulism in waterbirds: Mortality rates and new insights into how it spreads

Mallard. Photo by Bill Majoros (CC 2.0)

Outbreaks of botulism killed large percentages of waterbirds inhabiting a wetland in Spain. During one season, more than 80 percent of gadwalls and black-winged stilts died. The botulinum toxin's spread may have been abetted by an invasive species of water snail which frequently carries the toxin-producing bacterium, Clostridium botulinum, and which is well adapted to wetlands polluted by sewage. Global warming will likely increase outbreaks, said corresponding author Rafael Mateo, PhD. The research was published March 25th in Applied and Environmental Microbiology, a journal of the American Society for Microbiology.

Botulism is a major killer of waterbirds, including some endangered species. In earlier studies, some also published in Applied and Environmental Microbiology, these investigators had found that eutrophication of some of these wetlands, due to effluent from waste water treatment plants, was encouraging growth of C. botulinum and other bacterial pathogens of birds.

In the current study, the investigators surveyed mortality among the resident waterbirds, and investigated how the bacterium is spread. During two outbreaks, the investigators collected 43 dead white-headed ducks, representing seven percent and 17 percent of their maximum population on Navaseca lake during 2011 and 2012, respectively, said Mateo, who is Head of the Group of Wildlife Toxicology, at the Spanish Institute of Game and Wildlife Research, Cuidad Real, Spain. White-headed ducks are highly endangered, with only about ten thousand surviving individuals worldwide.

Additionally, the team found death rates of greater than 80 percent among gadwalls and black-winged stilts in 2011. Mortality estimates for white-headed ducks are probably low, said Mateo, explaining that scavengers frequently devour dead birds, and that it is difficult to find ailing or expired avians in the dense vegetation along the lake shore.

The team also investigated how the disease spreads. The main source of spread, previously known, is the "carcass-maggot cycle," said Mateo. "Birds feed on maggots growing in a carcass containing C. botulinum and its neurotoxin," and then die, with the cycle beginning anew as the dead birds become food for more maggots. "The spread of the outbreak is exponential," said Mateo.

Additionally, the investigators found that 30 percent of an invasive species of freshwater snail, collected during outbreaks, carried C. botulinum. These snails, Physa acuta, are an invasive species that is well adapted to wetlands polluted by sewage. They are likely sources of food for a number of different waterbird species, including mallards, gulls, and coots, said Mateo.

Differences in diets result in different levels of vulnerability among bird species. Flamingos and grebes appeared untouched by outbreaks, likely because they appear to feed mainly on prey species that do not carry C. botulinum, such as certain crustaceans, and/or possibly because they are more resistant genetically than other species to this pathogen.

Mateo warned that outbreaks would likely occur more frequently due to global warming. In earlier research, also published in Applied and Environmental Microbiology, his group showed that higher summer temperatures are associated with higher mortality rates among waterbirds during outbreaks. "We have observed that outbreaks occur when the mean temperature in July exceeds 26o C [79o F.]," he said. Additionally, when water is scarce due to drought, wetlands eutrophy more frequently, which favors anaerobic bacteria such as C. botulinum. Finally, birds tend to concentrate in the few wetlands that are maintained with treated sewage, which boosts mortality from botulism and other diseases, he said.

These wetlands, which are located in La Mancha, which was made famous by the novel, Don Quixote, and which are rich in biodiversity, are a UNESCO "biosphere reserve." Their unique habitat is important for many bird species, including migratory birds that breed there, such as the afore-mentioned white-headed duck. But outbreaks of botulism are common. "We wanted to characterize the ecology of the avian botulism in these wetlands to know to what degree human action--notably poor treatment of sewage--was determining the outbreaks' occurrence," said Mateo.

Citation: I. Anza, D. Vidal, J. Feliu, E. Crespo, and R. Mateo; Differences in the vulnerability of waterbird species to botulism outbreaks in Mediterranean wetlands: an assessment of ecological and physiological factors; Applied & Environmental Microbiology (25 March 2016); DOI:10.1128/AEM.00119-16.

Contact: Aleea Khan
American Society for Microbiology