Massachusetts butterflies move north as climate warms

Massachusetts butterflies move north as climate warms

ScienceDaily (Aug. 19, 2012) — The authors of a Harvard study published August 19 in Nature Climate Change gathered their data from an unlikely source -- the trip accounts of the Massachusetts Butterfly Club. During the past 19 years, the amateur naturalist group has logged species counts on nearly 20,000 expeditions throughout Massachusetts. Their records fill a crucial gap in the scientific record.

Once analyzed, the data show a clear trend. "Over the past 19 years, a warming climate has been reshaping Massachusetts butterfly communities," notes Greg Breed, lead author on the study and a postdoctoral fellow at the Harvard Forest in Petersham.

Subtropical and warm-climate species such as the giant swallowtail and zabulon skipper -- many of which were rare or absent in Massachusetts as recently as the late 1980s -- show the sharpest increases. At the same time, more than three-quarters of northerly species (species with a range centered north of Boston) are now declining in Massachusetts, many of them rapidly. Most impacted are the species that overwinter as eggs or small larvae, indicating that these overwintering stages may be much more sensitive to drought or lack of snow cover.

The study creates new questions for managing threatened species. "For most butterfly species, climate change seems to be a stronger change-agent than habitat loss," says Breed. "Protecting habitat remains a key management strategy, and that may help some butterfly species. However, for many others, habitat protection will not mitigate the impacts of warming."

Breed points to the frosted elfin, a species that receives formal habitat protection from the state. This southerly distributed butterfly is now one of the most rapidly increasing species in Massachusetts, with an estimated 1,000 percent increase since 1992. Some of this increase may be due to habitat protections, Breed allows. But over the same period, atlantis and aphrodite fritillaries, historically common summer butterflies in Massachusetts, have declined by nearly 90 percent -- yet these northerly species remain unprotected.

The kind of information collected by the Massachusetts Butterfly Club is becoming increasingly valuable to scientists and land managers alike. Elizabeth Crone, senior ecologist at the Harvard Forest and another co-author on the study, notes, "Careful datasets from amateur naturalists play a valuable role in our understanding of species dynamics. Scientists constantly ask questions, but sometimes the data just isn't there to provide the answers, and we can't go back in time to collect it. This study would not have been possible without the dedication and knowledge of the data collectors on those 19,000 club trips."

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Studies shed light on why species stay or go in response to climate change

Studies shed light on why species stay or go in response to climate change

ScienceDaily (Aug. 17, 2012) — Two new studies by scientists at UC Berkeley provide a clearer picture of why some species move in response to climate change, and where they go.

One study, published online Aug. 6, in the journal Global Change Biology, finds that changes in precipitation have been underappreciated as a factor in driving bird species out of their normal range. In the other study, published August 15 in the journal Proceedings of the Royal Society B, researchers found a sharp decrease in range for the Belding's ground squirrel, but noted some surprising areas where the species found refuge.

The two studies exemplify the type of research being explored through the Berkeley Initiative in Global Change Biology, or BiGCB, an ambitious effort to better understand and predict how plants and animals will respond to changing environmental conditions by studying how they have responded to earlier periods of climate change.

The first study's findings challenge the conventional reliance on temperature as the only climate-related force impacting where species live. The authors noted that as many as 25 percent of species have shifted in directions that were not predicted in response to temperature changes, yet few attempts have been made to investigate this.

"Our results redefine the fundamental model of how species should respond to future climate change," said study lead author Morgan Tingley, who began the research as a graduate student in UC Berkeley's Department of Environmental Science, Policy and Management. "We find that precipitation changes can have a major, opposing influence to temperature in a species' range shift. Climate change may actually be tearing communities of organisms apart."

The findings are based upon data gathered from the Grinnell Resurvey Project, which retraces the steps of Joseph Grinnell, founder of the UC Berkeley Museum of Vertebrate Zoology, in his surveys of Sierra Nevada wildlife from the early 1900s. The resurvey project, which began in 2003, was led by Craig Moritz, former UC Berkeley professor of integrative biology, and his colleagues at the Museum of Vertebrate Zoology.

For the bird study, the researchers included 99 species in 77 historic survey sites in Lassen Volcanic, Yosemite and Sequoia national parks, as well as in several national forests. In the century that has passed since the original Grinnell survey, summer and winter temperatures have increased an average of 1-2 degrees Celsius in the Sierra Nevada. Yosemite experienced the most warming -- with average temperatures increasing by 3 degrees Celsius -- while parts of Lassen actually got cooler and much wetter.

Among the bird species that moved upslope are the Savannah Sparrow, which shifted upward by 2,503 meters, and other meadow species such as the Red-winged Blackbird and Western Meadowlark. The ones that shifted their range downslope include both low-elevation species like the Ash-throated Flycatcher and Western Scrub-Jay, and high-elevation species like the Cassin's Finch and Red-breasted Nuthatch.

"Temperature did not explain the majority of these shifts," said Tingley, who is now a postdoctoral researcher at Princeton University's Program in Science, Technology and Environmental Policy. "Only when we included precipitation as an explanatory variable did our models adequately explain the movement patterns we observed."

The researchers found that while rising temperatures tended to push birds to cooler regions upslope, increased precipitation, which is more common at higher elevations, pulled them downslope.
"We believe many species may feel this divergent pressure from temperature and precipitation, and in the end, only one wins," said Tingley.

Notably, more than half of the bird species in each of the three study regions did not shift their range despite pressures from climate change. "Moving is a sign of adaptation, which is good from a conservation standpoint," said Tingley. "More worrisome are the species that have not shifted. How are they adapting? Are they moving, but we just can't detect it? Or are they slowly declining as environmental conditions gradually become less ideal where they live?"

The answers are complex, as illustrated by the second UC Berkeley paper about range changes for a species of squirrel found in the mountains of the western United States.

In that paper, researchers again used information obtained from the Grinnell Resurvey Project. Through visual observations and trapping surveys conducted throughout the mountains of California, they discovered that the Belding's ground squirrel had disappeared from 42 percent of the sites where they were recorded in the early 1900s. Extinctions were particularly common at sites with high average winter temperatures and large increases in precipitation over the last century.

"We were surprised to see such a dramatic decline in this species, which is well-known to Sierran hikers and was thought to be fairly common," said study lead author Toni Lyn Morelli, a former National Science Foundation postdoctoral researcher who was based at UC Berkeley. "In fact, the rate of decline is much greater than that seen in the same region for the pika, a small mountain-dwelling cousin of the rabbit that has become the poster child for the effects of climate warming in the contiguous United States."

Morelli added that the squirrels are thriving in areas that have been modified by humans. For example, irrigated Mono Lake County Park serves as an artificial oasis that sustains squirrel populations despite otherwise hot and dry conditions in eastern California.

"As predictions indicate that the range of the Belding's ground squirrel could disappear out of California by the end of the century, these areas might be particularly important for this and other climate-impacted species," said Morelli, who is now a technical advisor for the U.S. Forest Service's International Programs in the Democratic Republic of Congo.

Although the Belding's ground squirrel is widespread, the rapid decline in its distribution is of concern because it is an important source of food for raptors and carnivores. However, the paper suggests that even when climate change causes large range declines, some species can persist in human-modified areas.

"Taken together, these two studies indicate that many species have been responding to recent climate change, yet the complexities of a species' ecological needs and their responses to habitat modification by humans can result in unanticipated responses," said Steven Beissinger, professor at UC Berkeley's Department of Environmental Science, Policy and Management and the senior author on both studies. "This makes it very challenging for scientists to project how species will respond to future climate change."

Funding from the National Science Foundation, National Park Service, and California Landscape Conservation Cooperative helped support this research.

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Global warming causes more extreme shifts of the Southern Hemisphere's largest rain band, study suggests

Global warming causes more extreme shifts of the Southern Hemisphere's largest rain band, study suggests

ScienceDaily (Aug. 16, 2012) — The changes will result from the South Pacific rain band responding to greenhouse warming. The South Pacific rain band is largest and most persistent of the Southern Hemisphere spanning the Pacific from south of the Equator, south-eastward to French Polynesia.

Occasionally, the rain band moves northwards towards the Equator by 1000 kilometres, inducing extreme climate events.

The international study, led by CSIRO oceanographer Dr Wenju Cai, focuses on how the frequency of such movement may change in the future. The study finds the frequency will almost double in the next 100 years, with a corresponding intensification of the rain band.

Dr Wenju and colleagues turned to the extensive archives of general circulation models submitted for the fourth and fifth IPCC Assessments and found that increases in greenhouse gases are projected to enhance equatorial Pacific warming. In turn, and in spite of disagreement about the future of El Niño events, this warming leads to the increased frequency of extreme excursions of the rain band.

During moderate El Niño events with warming in the equatorial eastern Pacific, the rain band moves north-eastward by 300 kilometres. Countries located within the bands' normal position such as Vanuatu, Samoa, and the southern Cook Islands experience forest fires and droughts as well as increased frequency of tropical cyclones, whereas countries to which the rain band moves experience extreme floods.

"During extreme El Niño events, such as 1982/83 and 1997/98, the band moved northward by up to 1000 kilometres. The shift brings more severe extremes, including cyclones to regions such as French Polynesia that are not accustomed to such events," said Dr Cai, a scientist at the Wealth from Oceans Flagship.

"Understanding changes in the frequency of these events as the climate changes proceed is therefore of broad scientific and socio-economic interest."

A central issue for community adaptation in Australia and across the Pacific is understanding how the warming atmosphere and oceans will influence the intensity and frequency of extreme events. The impact associated with the observed extreme excursions includes massive droughts, severe food shortage, and coral reef mortality through thermally-induced coral bleaching across the South Pacific.

"Understanding changes in the frequency of these events as the climate changes proceed is therefore of broad scientific and socio-economic interest."

The paper, "More extreme swings of the South Pacific Convergence Zone due to greenhouse warming," was co-authored by Australian scientists Dr Simon Borlace, Mr Tim Cowan from CSIRO and Drs Scott Power and Jo Brown, two Bureau of Meteorology scientists at the Centre for Australian Weather and Climate Research, who were joined by French, US, UK, and Cook Island scientists.
The research effort from Australian scientists was supported by the Australian Climate Change Science Program, the CSIRO Office of Chief Executive Science Leader program, and the Pacific-Australia Climate Change Science and Adaptation Planning Program.

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Thousands of undiscovered plant species face extinction worldwide

Thousands of undiscovered plant species face extinction worldwide

ScienceDaily (July 7, 2010) — Faced with threats such as habitat loss and climate change, thousands of rare flowering plant species worldwide may become extinct before scientists can even discover them, according to a paper published today by a trio of American and British researchers in the journal Proceedings of the Royal Society B.

"Scientists have estimated that, overall, there could be between 5 million and 50 million species, but fewer than 2 million of these species have been discovered to date," says lead author Lucas Joppa of Microsoft Research in Cambridge, U.K., who received his doctorate from Duke University earlier this year. "Using novel methods, we were able to refine the estimate of total species for flowering plants, and calculate how many of those remain undiscovered."

Based on data from the online World Checklist of Selected Plant Families at the Royal Botanic Gardens, Kew, the scientists calculated that there are between 10 and 20 percent more undiscovered flowering plant species than previously estimated. This finding has "enormous conservation implications, as any as-yet-unknown species are likely to be overwhelmingly rare and threatened," Joppa says.

The new, more accurate estimate can be used to infer the proportion of all threatened species, says coauthor David Roberts of the Durrell Institute of Conservation and Ecology at the University of Kent. "If we take the number of species that are currently known to be threatened, and add to that those that are yet to be discovered, we can estimate that between 27 percent and 33 percent of all flowering plants will be threatened with extinction," he says.

"That percentage reflects the global impact of factors such as habitat loss. It may increase if you factor in other threats such as climate change," Joppa adds.

"The timing couldn't be more perfect," says co-author Stuart Pimm, Doris Duke Professor of Conservation Ecology at Duke's Nicholas School of the Environment. "The year 2010 is the International Year of Biodiversity. We wrote the paper to help answer the obvious questions: How much biodiversity is out there, and how many species will we lose before they are even discovered?"

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Report card shows Australia's oceans are changing

Report card shows Australia's oceans are changing

ScienceDaily (Aug. 16, 2012) — The report card provides information about the current and predicted-future state of Australia's marine climate and its impact on our marine biodiversity. The report card also outlines actions that are underway to help our marine ecosystems adapt to climate change.

"Although there are some concerning findings in the 2012 report card, the information we've compiled is helping to ensure that ocean managers and policy makers are best placed to respond to the challenge of managing the impact that climate change is having on these systems."

'Australia has some of the world's most unique marine ecosystems. They are enjoyed recreationally, generate considerable economic wealth through fisheries, aquaculture, and tourism, and provide irreplaceable services including coastal defence, oxygen production, nutrient recycling and climate regulation,' Project leader CSIRO's Dr Elvira Poloczanska said.

Key findings show :

• warming sea temperatures are influencing the distribution of marine plants and animals, with species currently found in tropical and temperate waters likely to move south
• new research suggests winds over the Southern Ocean and current dynamics are strongly influencing foraging of seabirds that breed in south-east Australia and feed close to the Antarctic each summer
• some tropical fish species have a greater ability to acclimatise to rising water temperatures than previously thought
• the Australian science community is widely engaged in research, monitoring and observing programs to increase our understanding of climate change impacts and inform management
• adaptation planning is happening now, from seasonal forecast for fisheries and aquaculture, to climate-proofing of breeding sites for turtles and seabirds.

Led by CSIRO, more than 80 Australian marine scientists from 34 universities and research organisations contributed to the 2012 report card. The report card draws on peer-reviewed research results from hundreds of scientists, demonstrating a high level of scientific consensus.

'Our knowledge of observed and likely impacts of climate change has greatly advanced since the first card in 2009,' Dr Poloczanska said.

Aspects of marine climate which have been analysed include changes in sea temperature, sea level, the East Australian Current, the Leeuwin Current, and El Niño-Southern Oscillation.

Marine biodiversity assessed for the report card include impacts on coral reefs; tropical, temperate and pelagic fish; marine mammals; marine reptiles; seabirds; mangroves; tidal wetlands; seagrass; macroalgae; marine microbes; phytoplankton and zooplankton. The two new sections included in the 2012 report card focus on the smallest and largest organisms in the oceans: microbes and whales.

The project has been funded by the Australian Government Department of Climate Change and Energy Efficiency, through the National Climate Change Adaptation Research Facility's Marine Biodiversity and Resources Adaptation Research Network, the Fisheries Research and Development Corporation, and CSIRO's Climate Adaptation National Research Flagship.

Report.

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Greenland melting breaks record four weeks before season's end

Greenland melting breaks record four weeks before season's end

ScienceDaily (Aug. 15, 2012) — Melting over the Greenland ice sheet shattered the seasonal record on August 8 -- a full four weeks before the close of the melting season, reports Marco Tedesco, assistant professor of Earth and atmospheric sciences at The City College of New York.

The melting season in Greenland usually lasts from June -- when the first puddles of meltwater appear -- to early-September, when temperatures cool. This year, cumulative melting in the first week in August had already exceeded the record of 2010, taken over a full season, according to Professor Tedesco's ongoing analysis.

"With more yet to come in August, this year's overall melting will fall way above the old records. That's a goliath year -- the greatest melt since satellite recording began in 1979," said Professor Tedesco.

This spells a change for the face of southern Greenland, he added, with the ice sheet thinning at its edges and lakes on top of glaciers proliferating.

Professor Tedesco noted that these changes jibe with what most of the models predict -- the difference is how quickly this seems to be happening.

To quantify the changes, he calculated the duration and extent of melting throughout the season across the whole ice sheet, using data collected by microwave satellite sensors. (The National Snow and Ice Data Center provided satellite data from the United States Air Force Defense Meteorological Satellite Program.)

This 'cumulative melting index' can be seen as a measure of the 'strength' of the melting season: the higher the index, the more melting has occurred. (The index is defined as the number of days when melting occurs multiplied by the total area subject to melting.)

Dr. Thomas Mote, Professor of Geography at the University of Georgia and colleague of Professor Tedesco, confirmed that the cumulative melt in 2012 had surpassed that of 2010 using a similar analysis.

The August 8th record differs from NASA's announcement of unprecedented melting in mid-July, reported by Professor Tedesco and other researchers. Then, they found that the Greenland ice sheet had melted over 97 percent of its surface.

"That event was exceptional in the sense that it was an extremely rare event," said Professor Tedesco. "Imagine Rio de Janeiro under a layer of snow and you get the idea."

The extreme melting detected in mid-July, on the other hand, generated liquid water that refroze after a few days. "This changed the physical properties of the snowpack -- making a slushy layer that turned into an icy crust after refreezing -- but very likely it did not add to the runoff of meltwater that makes sea levels rise."

The cumulative melting index, on the other hand, does account for water flowing to the ocean. The same meltwater can affect ice dynamics by lubricating the base of the ice sheet and speeding its slide toward the sea.

This year, Greenland experienced extreme melting in nearly every region -- the west, northwest and northeast of the continent -- but especially at high elevations. In most years, the ice and snow at high elevations in southern Greenland melt for a few days at most. This year it has already gone on for two months.

"We have to be careful because we are only talking about a couple of years and the history of Greenland happened over millennia," cautioned Professor Tedesco. "But as far as we know now, the warming that we see in the Artic is responsible for triggering processes that enhance melting and for the feedback mechanisms that keep it going. Looking over the past few years, the exception has become part of the norm."

The NASA Cryospheric Sciences Program and the National Science Foundation (NSF) sponsored this research.

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Widespread local 'extinctions' in tropical forest ‘remnants’

Widespread local 'extinctions' in tropical forest ‘remnants’

ScienceDaily (Aug. 9, 2012) — The small fragments of tropical forests left behind after deforestation are suffering extensive species 'extinction', according to new research led by the University of East Anglia (UEA).

Publishing August 14 in the journal PLoS ONE, the researchers carried out a comprehensive assessment to estimate the long-term impact of forest fragmentation and hunting on tropical biodiversity in Brazil.

They studied the Atlantic Forest of eastern Brazil, including the region's largest and least disturbed old-growth forest remnants, and found that remaining habitat fragments had been virtually emptied of their forest wildlife.

White-lipped peccaries were completely wiped out, while jaguars, lowland tapirs, woolly spider-monkeys and giant anteaters were virtually 'extinct'. Defaunation even extended to forest remnants with relatively intact canopy structures.

Widespread agricultural expansion has transformed the world's tropical forests, leaving few remaining blocks of primary forests unaltered by humans. There have been scattered reports of large mammal extinctions throughout Brazil, but the conservation value of a rapidly growing number of small forest remnants in highly-fragmented tropical forest landscapes has been hotly debated.

Senior author Prof Carlos Peres, of UEA's School of Environmental Sciences, said: "You might expect forest fragments with a relatively intact canopy structure to still support high levels of biodiversity. Our study demonstrates that this is rarely the case, unless these fragments are strictly protected from hunting pressure.

"There is no substitute for strict protection of remaining forest fragments in biodiversity hotspots like the Brazilian Atlantic Forest. Protection of forest cover alone is not enough to sustain tropical forest species, as overhunting compounds the detrimental effects of small habitat area and isolation."

Drawing on information from wildlife surveys and local interviews conducted at 196 forest fragments spanning a vast region covering 252.670 km², Dr Peres worked in partnership with Dr Gustavo Canale of the State University of Mato Grosso (UNEMAT). They investigated the effects of anthropogenic landscape alteration and other impacts, such as hunting, on the survival of large vertebrate species.
The researchers travelled more than 205,000km by treacherous dirt roads to uncover the largest and least disturbed forest fragments left in this vast region of the Atlantic Forest.

"We uncovered a staggering process of local extinctions of mid-sized and large mammals," said Dr Canale.

Around 90 per cent of the original Atlantic Forest cover (about 1.5 million km²) has been converted to agriculture, pasture and urban areas, and most of the remaining forest patches are smaller than a football pitch. On average, forest patches retained only four of 18 mammal species surveyed.

This study -- the first to document the loss of five large tropical forest mammals from one of the world's most endangered tropical biodiversity hotspots -- highlights the critical importance of the few legally protected areas established in the Atlantic Forest.

"We found that the protected areas retained the most species-rich forest fragments in the region," said Dr Canale. "We therefore recommend the implementation of new strictly protected areas, such as National Parks and Biological Reserves, including forest fragments containing populations of endangered, rare and endemic species, particularly those facing imminent extinctions."

However, many of the existing protected areas are far from secure.

Prof Peres said: "A growing number of reserves are being degraded, downsized, if not entirely degazetted, so holding on to the last remaining large tracts of primary forests will be a crucial part of the conservation mission this century."

With the global population projected to surpass nine billion by 2050, tropical forests will face increasing threats posed by anthropogenic land-use change and overexploitation.
"Human populations are exploding and very few areas remain untouched by the expanding cornucopia of human impacts," said Prof Peres. "It is therefore essential to enforce protection in areas that are nominally protected 'on paper'. The future of tropical forest wildlife depends on it."

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