An early spring drives butterfly population declines

Early snow melt triggers chains of events resulting in population declines in the mormon fritillary butterfly -- Study published early online in Ecology Letters

Stanford Univ (USA), March 15, 2012 –Early snow melt in the Colorado Rocky Mountains initiates two chains of events resulting in population decline in the mormon fritillary butterfly,Speyeria mormonia. One effect of snow melt date was readily detectable, but the second, cryptic effect required an understanding of the butterfly's biology. "This suggests that predicting effects of climate change on organisms' population sizes will be difficult in some cases due to lack of knowledge of the species' biology," noted Dr. Carol Boggs, professor in the department of biology at Stanford University and lead author on the study.

The study results are published early online in the journal Ecology Letters.

An initial understanding of the butterfly's life cycle and the factors determining egg production aided the research. Butterflies lay eggs (and then die) in the first summer; the caterpillars over-winter without eating and develop into adults in the second summer. In the laboratory, the amount of nectar a female ate determined the number of eggs she laid. This suggested that flower availability might be important to changes in population size.

Using long-term data on date of snow melt, butterfly population sizes, and flower numbers at the Rocky Mountain Biological Laboratory (RMBL) - located at 9,500 feet in the Colorado Rocky Mountains - researchers uncovered multiple effects of a single weather event, the date of snow melt, on change in population size of Speyeria mormonia butterflies. Early snow melt in the first year leads to lower availability of the butterfly's preferred flower species, due to exposure of newly developing plants to early-season frosts that kill flower buds. The researchers showed that reduced flower (nectar) availability per butterfly adversely affected butterfly population growth rate. Early snow melt in the second year of the butterfly life cycle worsened this impact, probably through direct killing of caterpillars during early-season frosts. The combined effects of snow melt in the two consecutive years explained more than four-fifths of the observed variation in population growth rate. "It is very unusual for research to uncover such a simple mechanism that can explain almost all of the variation in growth rate of an insect population", said Dr. David Inouye, professor of biology at the University of Maryland and co-author of the study.

"One climate parameter can have multiple effects on an organism's population growth," Dr. Boggs stated. "This was not previously recognized for species such as butterflies that live for only one year. We already can predict that this coming summer will be a difficult one for the butterflies, because the very low snowpack in the mountains this winter makes it likely that there will be significant frost damage."

"Long-term studies such as ours are important to understanding the 'ecology of place' and the effects of weather and possible climate change on population numbers," commented Dr. Inouye. "Research of this nature is critical to assessing the broader effects of weather on an ever-changing earth, and field stations such as RMBL, by facilitating longer-term, longitudinal studies, are an invaluable asset in this regard."

http://www.eurekalert.org/pub_releases/2012-03/bm-aes031412.php 

Biodiversity: Bat-killing disease spreading south

SUMMIT COUNTY — A bat-killing disease that has wiped out nearly 7 million bats across the eastern United States is spreading southward, wildlife officials said this week after detecting white-nose syndrome in Alabama.

The state hosts the country’s biggest colony of federally endangered gray bats, and conservation biologists said they’re concerned, because the species roosts in just a handful of caves. If the species is susceptible to the disease, the population could devastated in a short time.

“This is the southernmost appearance of white-nose syndrome so far — the disease is clearly moving down into warmer parts of the country,” said Mollie Matteson, a bat specialist with the Center for Biological Diversity. “America’s bats are in the throes of an unprecedented crisis that, without help from us, threatens to wipe some bat species off the face of the Earth.”

Bats bearing the telltale signs of the disease — fuzzy white smudges on their muzzles — were discovered at Russell Cave, in Jackson County, in early March by biologists from Alabama A&M University and the National Park Service. Definitive diagnosis was made via lab analysis at the University of Georgia. The Russell Cave complex features several miles of passages, with entrances on both private land and theRussell Cave National Monument, operated by the National Park Service.

All of Alabama, but particularly northeast Alabama where the bat disease was discovered, is rich in caves and in bats. All of the six species affected by white-nose syndrome thus far are found in the state, including the federally endangered Indiana bat.

Alabama joins 19 other states and four provinces as sites of the bat disease being either confirmed or suspected. While Alabama is the first new state this winter to document white-nose syndrome, the disease has been showing up in new locations in the South and Midwest over the last couple of months, including new counties in Kentucky, Ohio and Indiana. White-nose syndrome was discovered for the first time in all three states last year.

“White-nose syndrome has now infiltrated one of the most outstanding cave regions in the world, which historically has harbored amazing numbers of bats,” said Matteson. “We probably have not seen the worst of this tragedy, and the famous caves of Alabama, Kentucky, Indiana and other parts of the central and southern areas of the country may never be the same again.”

Before the bat disease showed up in Alabama, the spread of white-nose syndrome in Indiana and Kentucky was already deeply disturbing to biologists because the largest colonies of the Indiana bat are found in these states, as well as neighboring Missouri (where the disease-causing fungus was found on bats in 2010) and in southern Illinois.

White-nose syndrome was first documented in late winter 2006, in upstate New York. The disease rapidly spread throughout the Northeast. Bat mortality rates in affected caves and mines in that region have ranged from 70 percent to nearly 100 percent. This winter, biologists are finding that bats in West Virginia, where the disease struck in 2009, are also experiencing mortality rates greater than 90 percent.

Scientists have determined that the disease is caused by a previously unknown fungus, likely introduced by cave visitors from Europe. In Europe the fungus has been discovered on bats from France to Hungary, but it appears to do little to no harm to them.

“This disease is not slowing down, and it’s not likely to be any less catastrophic for hibernating bats in Alabama and the Midwest than it has been for bats in the northeastern states,” said Matteson. “White-nose syndrome has been an emergency from the beginning, but it’s now a Category 5. Our government needs to put serious money and science into solving this disease storm before it’s too late — not only for bats but for our crops and our farmers, who depend on bats for insect control.”

For more information, visit SaveOurBats.org.

http://summitcountyvoice.com/2012/03/15/biodiversity-bat-killing-disease-spreading-south/ 

Surprising pine beetle breeding habits help explain increasing tree damage, says CU study

Warming temperatures appear to allow pine beetles to now breed twice a year


Long thought to produce only one generation of tree-killing offspring annually, some populations of mountain pine beetles now produce two generations per year, dramatically increasing the potential for the bugs to kill lodgepole and ponderosa pine trees, University of Colorado Boulder researchers have found.

Because of the extra annual generation of beetles, there could be up to 60 times as many beetles attacking trees in any given year, their study found. And in response to warmer temperatures at high elevations, pine beetles also are better able to survive and attack trees that haven't previously developed defenses.

These are among the key findings of Jeffry Mitton, a CU-Boulder professor of ecology and evolutionary biology, and Scott Ferrenberg, a graduate student in that department. The study is being published this month in The American Naturalist.

This exponential increase in the beetle population might help to explain the scope of the current beetle epidemic, which is the largest in history and extends from the Sangre de Cristo Mountains in New Mexico to the Yukon Territory near Alaska.

"This thing is immense," Mitton said. The duo's research, conducted in 2009 and 2010 at CU's Mountain Research Station, located about 25 miles west of Boulder, helps explain why.

"We followed them through the summer, and we saw something that had never been seen before," Mitton said. "Adults that were newly laid eggs two months before were going out and attacking trees" -- in the same year. Normally, mountain pine beetles spend a winter as larvae in trees before emerging as adults the following summer.

These effects may be particularly pronounced at higher elevations, where warmer temperatures have facilitated beetle attacks. In the last two decades at the Mountain Research Station, mean annual temperatures were 2.7 degrees Fahrenheit warmer than they were in the previous two decades.

Warmer temperatures gave the beetle larvae more spring days to grow to adulthood. The number of spring days above freezing temperatures increased by 15.1 in the last two decades, Mitton and Ferrenberg report. Also, the number of days that were warm enough for the beetles to grow increased by 44 percent since 1970.

The Mountain Research Station site is about 10,000 feet in elevation, 1,000 feet higher than the beetles have historically thrived. In their study, Mitton and Ferrenberg emphasize this anomaly.

"While our study is limited in area, it was completed in a site that was characterized as climatically unsuitable for (mountain pine beetle) development by the U.S. Forest Service only three decades ago," they write.

But in 25 years, the beetles have expanded their range 2,000 feet higher in elevation and 240 miles north in latitude in Canada, Mitton said.

Ferrenberg had the idea to monitor the beetles at higher elevations partly because trees at lower elevations have been attacked by beetles for centuries and have developed some defenses.

Lodgepole pines at higher elevations tended to have a lower density of resin ducts, which transport resin, the sole defense against beetles. The number of resin ducts in a tree can be a "marker" for whether a tree has a higher or lower resistance to a beetle attack, Ferrenberg said.

The trees at higher elevations had not faced the same intensity of beetle attacks as those at lower elevations until temperatures warmed, and they have not faced pressures of natural selection exerted by attacking beetles. "The trees in that area are somewhat naïve in their response," Ferrenberg said.

These data help explain why westbound motorists emerging from the Eisenhower Tunnel on I-70 can look up, from 11,000 feet in elevation, and see beetle-killed trees. "We think we see some of the reason for the fact that this epidemic is so widespread," Mitton said.


http://www.eurekalert.org/pub_releases/2012-03/uoca-spb031412.php 

Flower eating mammals competed with dinosaurs

Scientists examining the skulls of a group of ancient mammals found that their love for flowers allowed the beaver-like mammals, called multituberculates, to blossom during the dinosaur era.

The creatures, which adapted to eating flowering plants, flourished during the last 20 million years of the dinosaurs' reign and even survived the mass extinction that wiped out the dinosaurs 65 million years ago, the researchers said.

Once the dinosaurs disappeared, the mammals continued to prosper eating angiosperms, the flowering plants that only started to appear around 140 million years ago. And gradually, they evolved into a diverse group of animals ranging in size from that of a mouse to a beaver, they said

The creatures, the scientists believe, only vanished from the Earth some 34 million years ago after losing out to other mammals such as primates, hoofed species and rodents, the Daily Mail reported. 


Read on:  http://www.phenomenica.com/2012/03/flower-eating-mammals-competed-with.html

Conservation group claims koala numbers fudged

The Australian Koala Foundation has accused the state government of "appalling science" to bolster koala numbers in its latest koala population survey so it would not lose koala planning control to the federal government.

But the state government has rejected those claims.

Surveys show there are possibly only 1500 koalas today in southeast Queensland's Koala Coast, between Redlands and Brisbane, which is down from an estimated 6240 in 1996.

That is the worst-case scenario in the most recent survey of koalas in the region that includes Redlands, the eastern portion of Logan and the southeast portion of Brisbane.

The Queensland government this year released the findings of the 2010 koala survey, the latest in a series since 1996.

The Koala Coast Koala Population Population Report 2010 estimated there were 1991 koalas - "plus or minus 488" - in the 1751 hectares of bushland two years ago.

The survey includes in the fine detail an admission that koala numbers on the Koala Coast were boosted by "approximately 270 animals" when fauna spotters found four extra koalas in an area of bushland.

"The estimated increase at this site applied over the full area of the Lower Density Bushland Stratum resulted in the overall Koala Coast abundance being increased by 270 animals over what it would have been without this particular component," the report finds.

Read more: http://www.brisbanetimes.com.au/queensland/state-election-2012/conservation-group-claims-koala-numbers-fudged-20120314-1v3am.html#ixzz1pNMTkLEx