As climate warms, bark beetles march on high-elevation forests

Terry Devitt in the University of Wisconsin-Madison News: Trees and the insects that eat them wage constant war. Insects burrow and munch; trees deploy lethal and disruptive defenses in the form of chemicals. But in a warming world, where temperatures and seasonal change are in flux, the tide of battle may be shifting in some insects’ favor, according to a new study.

In a report published today (Dec. 31, 2012) in the Proceedings of the National Academy of Sciences, a team of scientists from the University of Wisconsin-Madison reports a rising threat to the whitebark pine forests of the northern Rocky Mountains as native mountain pine beetles climb ever higher, attacking trees that have not evolved strong defenses to stop them.

The whitebark pine forests of the western United States and Canada are the forest ecosystems that occur at the highest elevation that sustains trees. It is critical habitat for iconic species such as the grizzly bear and plays an important role in governing the hydrology of the mountain west by shading snow and regulating the flow of meltwater.

“Warming temperatures have allowed tree-killing beetles to thrive in areas that were historically too cold for them most years,” explains Ken Raffa, a UW-Madison professor of entomology and a senior author of the new report. “The tree species at these high elevations never evolved strong defenses.”

A warming world has not only made it easier for the mountain pine beetle to invade new and defenseless ecosystems, but also to better withstand winter weather that is milder and erupt in large outbreaks capable of killing entire stands of trees, no matter their composition....

A stand of aspens, with pines in the background, in the Rio Grande National Forest in southern Colorado, U.S. Department of Agriculture

Environmental threat map highlights Great Lakes restoration challenges

Space Daily via SPX: A comprehensive map three years in the making is telling the story of humans' impact on the Great Lakes, identifying how "environmental stressors" stretching from Minnesota to Ontario are shaping the future of an ecosystem that contains 20 percent of the world's fresh water.

In an article to be published in the Proceedings of the National Academy of Sciences, a group led by researchers at the University of Michigan reports on an expansive and detailed effort to map and cross-compare environmental stresses and the ecological services provided by the five lakes.

Their efforts have produced the most comprehensive map to date of Great Lakes' stressors, and also the first map to explicitly account for all major types of stressors on the lakes in a quantitative way.

"Despite clear societal dependence on the Great Lakes, their condition continues to be degraded by numerous environmental stressors," said David Allan, the project's lead researcher and a professor of aquatic sciences at the University of Michigan's School of Natural Resources and Environment.

The map gives federal and regional officials an unprecedented scientific foundation upon which to sustainably manage the Great Lakes, the researchers conclude.

The environmental stress map was developed by a bi-national team of researchers from academia and environmental organizations known as the Great Lakes Environmental Assessment and Mapping (GLEAM) project. The team drew upon the latest and best data from federal and state agencies as well as non-governmental organizations and individual researchers....

The Bayfield River entering Lake Huron, shot by Doc Searls, Wikimedia Commons via Flickr, under the Creative Commons Attribution-Share Alike 2.0 Generic license

Emerging consensus shows climate change already having major effects on ecosystems and species

US Geological Survey: Plant and animal species are shifting their geographic ranges and the timing of their life events – such as flowering, laying eggs or migrating – at faster rates than researchers documented just a few years ago, according to a technical report on biodiversity and ecosystems used as scientific input for the 2013 Third National Climate Assessment.

The report, Impacts of Climate Change on Biodiversity, Ecosystems, and Ecosystem Services, synthesizes the scientific understanding of the way climate change is affecting ecosystems, ecosystem services and the diversity of species, as well as what strategies might be used by natural resource practitioners to decrease current and future risks. More than 60 federal, academic and other scientists, including the lead authors from the U.S. Geological Survey, the National Wildlife Federation and Arizona State University in Tempe, authored the assessment.

"These geographic range and timing changes are causing cascading effects that extend through ecosystems, bringing together species that haven't previously interacted and creating mismatches between animals and their food sources," said Nancy Grimm, a scientist at ASU and a lead author of the report.

...Another key finding is the mounting evidence that population declines and increased extinction risks for some plant and animal species can be directly attributed to climate change. The most vulnerable species are those already degraded by other human-caused stressors such as pollution or exploitation, unable to shift their geographic range or timing of key life events, or that have narrow environmental or ecological tolerance. For example, species that must live at high altitudes or live in cold water with a narrow temperature range, such as salmon, face an even greater risk due to climate change.

"The report clearly indicates that as climate change continues to impact ecological systems, a net loss of global species’ diversity, as well as major shifts in the provision of ecosystem services, are quite likely," said Michelle Staudinger, a lead author of the report and a USGS and University of Missouri scientist....

Snow geese at Sacramento National Wildlife Refuge, shot by Brocken Inaglory, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported licence

Drought in the Horn of Africa delays migrating birds

University of Copenhagen News: The catastrophic drought last year in the Horn of Africa affected millions of people but also caused the extremely late arrival into northern Europe of several migratory songbird species, a study published today in Science shows. Details of the migration route was revealed by data collected from small backpacks fitted on birds showing that the delay resulted from an extended stay in the Horn of Africa.

The extensive 2011 drought in the Horn of Africa had significant consequences for European songbirds such as thrush nightingale and red-backed shrike. These birds visit northern Europe every spring to mate and take advantage of ample summer food resources.

However, their spring migrating route from southern Africa to northern latitudes passes directly through the Horn of Africa, where the birds stop to feed and refuel for the next stage of their migration.

"Our research was able to couple the birds’ delayed arrival in Europe with that stopover in the Horn of Africa. Here they stayed about a week longer in 2011 than in the years before and after 2011. Because of the drought, the birds would have needed longer to feed and gain energy for their onward travel, causing delayed arrival and breeding in Europe. This supports our theory that migrating animals in general are dependent on a series of areas to reach their destination," says Associate Professor Anders Tøttrup from the Center for Macroecology, Evolution and Climate at the University of Copenhagen....

Nestlings of red-backed shrike, an 1887 painting by Bruno Liljefors

Drought-stressed trees face race to adapt

CNN: Scientists have known for some time that climate change and the impacts of longer droughts and higher temperatures could pose a problem for forests. But many thought it would only affect a minority of trees, perhaps just those in extremely arid regions.

However, new research is showing that a large majority of tree species around the world are operating on the brink of collapse. If the predicted pace of climate change continues, many may not be able to adapt in time and large numbers could die-off.

The authors of the study, whose findings were published in the scientific journal Nature, looked at 226 different tree species from 81 sites around the world, covering the full range of climatic conditions, from Mediterranean-type arid to the tropical Amazon rainforest.

They found that 70% of the trees studied adapt closely to the local environment, whether arid or tropical, absorbing just enough water in order to survive, but leaving them highly vulnerable to minor shifts in rainfall and drought stress.

"We thought that in the dry areas, plants would have adapted to survive more than ones growing in the wet, but we found they were all equally vulnerable. It was a big surprise," says Steven Jansen, from Germany's Ulm University and co-author of the study.

In periods of drought, the vascular network (xylem) distributing water and nutrients around the tree develops air bubbles which hinder the passage of water. As drought stress increases, these blockages, or "embolisms," accumulate eventually causing the tree to dry out and die....

Tree rings shot by Arpingstone, public domain

Scientists pioneer method to predict environmental collapse

Terra Daily via SPX: Scientists at the University of Southampton are pioneering a technique to predict when an ecosystem is likely to collapse, which may also have potential for foretelling crises in agriculture, fisheries or even social systems.

The researchers have applied a mathematical model to a real world situation, the environmental collapse of a lake in China, to help prove a theory which suggests an ecosystem 'flickers', or fluctuates dramatically between healthy and unhealthy states, shortly before its eventual collapse.

Head of Geography at Southampton, Professor John Dearing explains: "We wanted to prove that this 'flickering' occurs just ahead of a dramatic change in a system - be it a social, ecological or climatic one - and that this method could potentially be used to predict future critical changes in other impacted systems in the world around us."

A team led by Dr Rong Wang extracted core samples from sediment at the bottom of Lake Erhai in Yunnan province, China and charted the levels and variation of fossilised algae (diatoms) over a 125-year period. Analysis of the core sample data showed the algae communities remained relatively stable up until about 30 years before the lake's collapse into a turbid or polluted state.

However, the core samples for these last three decades showed much fluctuation, indicating there had been numerous dramatic changes in the types and concentrations of algae present in the water - evidence of the 'flickering' before the lake's final definitive change of state. Rong Wang comments: "By using the algae as a measure of the lake's health, we have shown that its eco-system 'wobbled' before making a critical transition - in this instance, to a turbid state....

Géza Maróti's plan of Atlantis mock-up, around 1941 -- public domain

Dust Bowl reflections-- a Carbon Based original

One way to address climate change today is to fully appreciate yesterday's climate disasters. The recent broadcast of Ken Burns' documentary on the Dust Bowl is a starting point, if an often annoying one. Plaintive violins and banjos keep the nostalgia turned up high.  The personality-focused style of these shows often blunts general insights and muffle the sharp points that need to be kept in mind.   But at least the talking heads in "The Dust Bowl" were explicit in stating that the catastrophe was manmade, like today's climate change woes.

The story is a familiar blend of fragile prospertiy, delusional hope and harsh comeuppance. The Homestead Act after the Civil War lured growing numbers of farmers onto semiarid grasslands, with few trees and little water.  A period of higher than normal rainfall masked the consequences of this influx for a while.  Many Plains dwellers believed that the wetter weather was permanent. 

Policy choices played a destructive role in adding to the risks. "Rain follows the plow" was the dunderheaded motto used to promote the settlement.  Free or cheap land and price supports for wheat during World War I led to good years that attracted more immigrants. By this time, most residents were deeply attached to the land.

During these fat years, deep plowing destroyed the millions of acres of grasses that held the soil in place, and brought marginal land under cultivation. Fields were often left bare, without cover cropping despite the constant winds.  Topsoils dried up even before the drought returned, which was the prelude to the apocalyptic dust storms of the 1930s.

When the rain stopped and the dust storms came, most people in the area underestimated the dangers.  They said, "We've seen droughts before, we've seen dust storms before," even though the storms of the 1930s were larger and longer lasting. Moving away seemed unthinkable.   As the market for wheat collapsed and the drought worsened, most farmers were loath to see their own part in fomenting the disaster.  Just leave us alone, they said, and the rains will come back, and things will return to normal. 

But the drought got worse. One farmer lamented, "One of those years, we put our entire wheat crop in one wagon."  Children and the elderly sickened and died from "dust pneumonia."

The exodus from the Dust Bowl eventually picked up after more than five years of no money and no crops.  "A migration of the defeated," the narrator intoned, it dwarfed the 19th century US migrations, but it's largely gone from public notice. 

Several of witnesses summoned by Burns showed some insight into the problem. Bernard Lewis, a child at the time, said, "We always had hope that next year was going to be better... we learned slowly." These hopes were cruelly shredded in the years of depression and dust, only to return in a blink when conditions improved.

In the last few minutes of part two of the "The Dust Bowl," various interviewees acknowledged the need for humility and for staying mindful of the land's limits and needs.  But the script did little to explain the predictable market failures that  worsened tolerable natural cycles into outright catastrophe.

The government's response was a mixed bag. Short-term, the Works Progress Administration in 1935 launched projects that, though they were condemned as make work, nevertheless brought labor to the region and helped busted farmers. More scientific agriculture was brought to bear on the problem, with contour plowing and better erosion control replacing destructive land use habits of yore.  But the improvements were modest, and the government did little to slow down the the reintroduction of the same detrimental practices once the rains returned.   In the 1940s, overplanting and developing marginal land resumed quickly. Smaller dust storms returned in the 1950s, held somewhat in check by the new methods.

Roosevelt may have brought hope to the region, but the political calculus left no room for the most sustainable measure in the long term -- leave the land alone, and avoid development where there isn't the water to support it.  We see a similar pattern happening today in the planting of crops for biofuel, and in the Great Plains today, in pumping ancient groundwater from the Ogallala Aquifer. One of the speakers estimates that only twenty years of water remain -- and then it's back to the drought cycle.

After the Dot Com bust after 2000, the Onion ran a headline:  "Americans angrily demand new bubble to invest in."   Maybe it's human nature. But it's worth resisting. The bad ecological outcomes of climate change that threaten us today are potentially much worse than the Dust Bowl.

FSA; Dust Storm; "Farmer and sons walking in the face of a dust storm"; Cimarron County, Oklahoma. Shot by Arthur Rothstein in 1936. This image gets a few minutes of its own in the Ken Burns documentary

Streams show signs of degradation at earliest stages of urban development

US Geological Survey Newsroom: The loss of sensitive species in streams begins to occur at the initial stages of urban development, according to a new study by the USGS. The study found that streams are more sensitive to development than previously understood.

"We tend not to think of waterways as fragile organisms, and yet that is exactly what the results of this scientific investigation appear to be telling us," said USGS Director Marcia McNutt. "Streams are more than water, but rather communities of interdependent aquatic life, the most sensitive of which are easily disrupted by urbanization."

Contaminants, habitat destruction, and increasing streamflow flashiness resulting from urban development can degrade stream ecosystems and cause degradation downstream with adverse effects on biological communities and on economically valuable resources, such as fisheries and tourism.

For example, by the time urban development had approached 20 percent in watersheds in the New England area, the aquatic invertebrate community had undergone a change in species composition of about 25 percent.

The study also found that the health of highly-degraded streams can be improved by implementing management actions that are designed to reduce specific stressors.

"Biological communities were not resistant to even low levels of urban development. In the study sensitive invertebrate species were being lost over the initial stages of development in relatively undisturbed watersheds," said Dr. Gerard McMahon, lead scientist on the study. "Understanding how stream ecosystems are impacted by urban development can assist in the development of management actions to protect and rehabilitate urban stream ecosystems."...

An urban stream in a small town, shot by Sprocket2cog, Wikimedia Commons,  under the Creative Commons Attribution-Share Alike 3.0 Unported license