Genetics show stronger pine beetle evolving; stream flow increases in infected forests: studies

A new study, based at the University of Alberta, released this week, indicates that natural selection may be making the mountain pine beetle more tolerant of colder temperatures and that the beetle may be evolving the ability to fly longer distances.

A second study, from the Colorado School of Mines, also released this week, is tracking how the extent of pine beetle infected or killed trees in forests is changing ground water and stream flows.

The mountain pine beetle infestation has wreaked havoc in North America, across forests from the American Southwest to British Columbia and Alberta. Millions of hectares of forest have been lost, with severe economic and ecological impacts from a beetle outbreak ten times larger than previous ones.

Dust from beetle killed wood is believed partially responsible for the explosions at the Lakeland Mill in Prince George and the Babine Forest Products mill in Burns Lake. The explosion in early 2012 at the Babine Forest Products mill killed two workers and injured another twenty. The Lakeland Mill explosion killed two workers and injured twenty four others.

As part of the fight to contain the mountain pine beetle, scientists recently sequenced the pine beetle genome.

Using that genome, Jasmine Janes and colleagues at the University of Alberta, with assistance from the University of British Columbia and the University of Northern British Columbia, used genetics to track how the pine beetle was able to expand its range so rapidly. The study was published in Molecular Biology and Evolution.

Studied at molecular level

While teams of researchers have tracked the path of the pine beetle across BC on the ground, how the beetle spread so easily “is only beginning to be understood at the molecular level,” the study says.

Pine beetles were collected from 27 sites in Alberta and British Columbia. The University of Alberta scientists were especially interested in how the pine beetle was able to jump across the Rockies, something that earlier researchers believed would not happen.

By looking at the genetic markers, the team concluded that the pine beetle may have been able to spread by adjusting its cellular and metabolic functions to better withstand cooler climates and facilitate a larger geographic dispersal area.

In an e-mail to Northwest Coast Energy News, Janes said the research looked at genomic signatures to find out how the beetle had been able to spread into Alberta – where did it come from, what route did it take and how did it overcome the physical and climatic barriers that we had always assumed?

The research discovered that there are two genetically different populations of pine beetles, one from the south of British Columbia and Alberta and one in the north. Another group of pine beetles, found near Valemount, “were harder to classify as being from either north or south genetically. The beetles in this area were showing higher genetic diversity.”

The pine beetle has always been around and killed older trees (called “low quality hosts”), helping to renew the ecosystem. There were also larger five-year infestations that occurred on a 20 to 40 year cycle. The current pine beetle “epidemic” in BC has gone on now for more than 20 years, with the pine beetle “observed in previously unrecorded numbers” over a much wider area

It is generally believed that climate change has help the pine beetle survive milder winters.

The study notes:

Successful establishment of mountain pine beetle on pure jack pine in northern Alberta has raised concerns that the mountain pine beetle will continue to expand its range into the vast boreal forest of jack pine that extends across North America from the Northwest Territories to the Atlantic Coast.

The teams concludes that one group of the beetles originated in southwestern BC perhaps from Whistler or Manning Park. Then the beetles spread north up the west coast of BC toward Houston “with rapid population size increases in central and northern BC and then dispersed long distances with prevailing winds toward the east and Alberta.”

Some of the beetles from southwestern BC appear to have taken a different route, moving more slowly eastward in the south of BC toward Crowsnest Pass area and then moving northward along the base of the Rockies, Janes said, adding. “Our research suggests that these two routes have then met in the middle again, around Valemount and that is why we see the genetic patterns across the landscape that we observed.”

Selective pressure

The second part of the research was answering the question of how the beetles were able to do this. How could they withstand the colder temperatures to spread further north and east?

To answer the scientists used the same genetic markers (single nucleotide polymorphisms) to conduct “selective sweeps” of the beetle genome. The sweeps look for unusual genetic markers that could indicate the beetles are under “selective pressure.”

The study looked at specific functions in the beetle: the genes that govern “actin filaments” that “control muscle contractions like shivering and moving wings”; “the synthesis of cholesterol that provides energy for metabolic activities” and transport of ions across cell membranes.

Normally, female pine beetles can only fly short distances to find a new host tree to lay eggs. They can travel longer distances if they are up in the tree canopy and are then carried by the wind. Stronger pine beetles that can fly longer distances show the threat is likely evolving.

The study concludes that Canadian Mountain Pine Beetle range expansion:

may continue as populations are currently exhibiting signals of selection. These signals suggest ongoing adaptation of metabolic and cellular processes that could potentially allow them to withstand colder temperatures, shift developmental timing and facilitate longer dispersal flights.

Janes said further research is required to fully validate and understand these signatures of selection, but it does suggest that the beetle is adapting and that is why it “may have been able to breach the Rocky Mountains”

Water and trees

Precipitation samples
Colorado scientists collected precipitation samples to determine their unique chemical fingerprints. ( Lindsay Bearup/Colorado School of Mines)
In Colorado alone, the mountain pine beetle has caused the deaths of more than 3.4 million acres of pine trees. The new research findings show the consequences of an obvious observation: Dead trees don’t drink water

The Colorado study asked how all those dead trees are changing stream flow and water quality?

“The unprecedented tree deaths caused by these beetles provided a new approach to estimating the interaction of trees with the water cycle in mountain headwaters like those of the Colorado and Platte Rivers,” said Reed Maxwell a hydrologist at the Colorado School of Mines.

Maxwell and colleagues have published results of their study of beetle effects on stream flows in this week’s issue of the journal Nature Climate Change.

As the trees die, they stop taking up water from the soil, known as transpiration. Transpiration is the process of water movement through a plant and its evaporation from leaves, stems and flowers.

The “unused” water then becomes part of the local groundwater and leads to increased water flows in nearby streams.

“Large-scale tree death due to pine beetles has many negative effects,” says Tom Torgersen of the US National Science Foundation’s Directorate for Geosciences and program director for the NSF’s Water, Sustainability and Climate program.

“This loss of trees increases groundwater flow and water availability, seemingly a positive,” Torgersen says.

“The total effect, however, of the extensive tree death and increased water flow has to be evaluated for how much of an increase, when does such an increase occur, and what’s the water quality of the resulting flow?”

Under normal circumstances, green trees use shallow groundwater in late summer for transpiration.

Red- and gray-phase trees–those affected by beetle infestations–stop transpiring, leading to higher water tables and greater water availability for groundwater flow to streams.

The Colorado study shows that the fraction of late-summer groundwater flows from affected watersheds is about 30 per cent higher after beetles have infested an area, compared with watersheds with less severe beetle attacks.

“Water budget analysis confirms that transpiration loss resulting from beetle kill can account for the increase in groundwater contributions to streams,” write Maxwell and scientists Lindsay Bearup and John McCray of the Colorado School of Mines, and David Clow of the U.S. Geological Survey, in their paper.

Dead trees create changes in water quality

“Using ‘fingerprints’ of different water sources, defined by the sources’ water chemistry, we found that a higher fraction of late-summer stream flow in affected watersheds comes from groundwater rather than surface flows,” says Bearup.

“Increases in stream flow and groundwater levels are very hard to detect because of fluctuations from changes in climate and in topography. Our approach using water chemistry allows us to ‘dissect’ the water in streams and better understand its source.”

With millions of dead trees, adds Maxwell, “we asked: What’s the potential effect if the trees stop using water? Our findings not only identify this change, but quantify how much water trees use.”

An important implication of the research, Bearup says, is that the change can alter water quality.

The new results, she says, help explain earlier work by Colorado School of Mines scientists. “That research found an unexpected spike in carcinogenic disinfection by-products in late summer in water treatment plants.”

Where were those water treatment plants located? In bark beetle-infested watersheds.


The TRIA project (a collaboration of researchers at the University of Alberta, University of British Columbia, University of Montreal, University of Northern British Columbia). The TRIA project investigates the physiology, genetics and ecology of all three players in the mountain pine beetle system – the pines (lodgepole and jack pine, and their hybrids), the beetle and the fungus (several types).

The Colorado study is funded by the National Science Foundation’s (NSF) Water, Sustainability and Climate (WSC) Program. WSC is part of NSF’s Science, Engineering and Education for Sustainability initiative.

Canadian scientists propose nine step program to save waterways and fish


John Richardson
Tomorrow’s clean water depends on nine guiding principles, says UBC Forestry Prof. John Richardson. (Martin Dee/UBC)

A group of biologists from across Canada have proposed a nine step program to sustain healthy waterways and fisheries not only in this country but around the world.

The key to clean waterways and sustainable fisheries is for the management plan to follow nine guiding principles of ecological water management, according to John Richardson, a professor in the Dept. of Forest and Conservation Sciences at the University of British Columbia, one of 15 freshwater biologists who created the framework to help protect fish and ecosystems into the future.

Fish habitats need waterways that are rich in food with places to hide from predators and lay eggs, according to the framework published on January 31 in the journal Environmental Reviews.
“Fish are strongly impacted when nutrients, sediments or pollutants are added to their habitat. We cannot protect fish without maintaining a healthy freshwater ecosystem,” Richardson,who led the policy section on protecting fish habitats, said in a UBC news release. Other policy sections addressed areas such as climate change and biodiversity.

Read the complete paper on the Environmental Reviews site.

Humans have put key waterways at risk because of land development and the loss of the vegetation along rivers and streams, Richardson said, adding connecting waterways are also critical for healthy ecosystems. “If fish can’t get to breeding or rearing areas because of dams, culverts, water intakes or other changes to their habitats, then the population will not survive,” he said.

With more pressure on Canada’s waterways, Richardson and his colleagues wanted to create a framework of evidence-based principles that managers, policy makers and others could easily use in their work. “It’s a made in Canada solution, but the principles could be applied anywhere in the world,” he said.

The paper says:

Freshwater ecosystems are among the most imperiled on Earth with extinction rates of freshwater fauna higher than for many other ecosystems and vastly exceeding historic background rates/ Freshwater is vital to humans, and clean water is rapidly becoming a limiting resource for many societies. The greatest threat to freshwater ecosystems is the loss or alteration of freshwater habitats through human development yet our societies and economy depend directly on the services provided by healthy freshwater ecosystems.

It also notes:

Most ecosystem services of fishes are supported by a diverse fauna, not by merely the few species directly favoured by humans. Humans live side-by-side with fishes and other aquatic organisms in watersheds, and we derive our quality of life from the health of these ecosystems.

The paper, which was supported in part by federal government financing, only touches on the controversy over the gutting of the environmental protection for Canadian waterways by the Harper government. It goes on to stay that the protests are not enough and more is needed:

Recent changes to Canadian fisheries policies have motivated responses by the public and the scientific community yet a broad contemporary scientific assessment of what is required to manage freshwater fisheries resources is lacking. A template of the core ecological concepts underlying sound fisheries policies, based on the best available science will support policy and management decisions and the design of monitoring programs to evaluate the success of these actions.

With more pressure on Canada’s freshwater ecosystems, Richardson and his colleagues wanted to create a framework of evidence-based principles that managers, policy makers and others could easily use in their work. “It’s a made in Canada solution, but the principles could be applied anywhere in the world,” he says.

Healthy freshwater ecosystems are shrinking and reports suggest that the animals that depend on them are becoming endangered or extinct at higher rates than marine or terrestrial species, says Richardson. Humans also depend on these ecosystems for basic resources like clean drinking water and food as well as economic activity from the natural resource sector, tourism and more.

The components of a successful management plan include:

  • Protect and restore habitats for fisheries
  • Protect biodiversity as it enhances resilience and productivity
  • Identify threats to ecosystem productivity
  • Identify all contributions made by aquatic ecosystems
  • Implement ecosystem based-management of natural resources while acknowledging the impact of humans
  • Adopt a precautionary approach to management as we face uncertainty
  • Embrace adaptive management – environments continue to change so research needs to be ongoing for scientific evidence-based decision making
  • Define metrics that will indicate whether management plans are successful or failing
  • Engage and consult with stakeholders
  • Ensure that decision-makers have the capacity, legislation and authority to implement policies and management plans.

These recommendations are based on nine principles of ecology:

  • Acknowledge the physical and chemical limits of an ecosystem
  • Population dynamics are at work and there needs to be a minimum number of fish for the population to survive
  • Habitat quantity and quality are needed for fish productivity
  • Connecting habitats is essential for movement of fish and their resources
  • The success of freshwater species is influenced by the watershed
  • Biodiversity enhances ecosystem resilience and productivity
  • Global climate change affects local populations of fish
  • Human impacts to the habitat affect future generations of fish
  • Evolution is important to species survival

Climate change decreases some mussel beds in Salish Sea by 51%: UBC study

A UBC study shows that some mussel beds  in the Salish Sea have decreased by 51 per cent over the past 52 years, a consequence of gradually rising temperatures off Vancouver Island, the Gulf and San Juan Islands and Washington’s Olympic peninsula.

The study shows that the climate change is already affecting species by not only causing stress but changing the complex relationship among the species in an ecosystem, as some species may become relatively stronger and others weaker.

 University of British Columbia associate professor of zoology Christopher Harley say climate change will  bring biodiversity loss caused by a combination of rising temperatures and predation – and may be more severe than currently predicted.

The study, published in the current issue of the journal Science, examined the response of rocky shore barnacles and mussels to the combined effects of warming and predation by sea stars.

Harley surveyed the upper and lower temperature limits of barnacles and mussels from the cool west coast of Vancouver Island to the warm shores of the San Juan Islands, where water temperature rose from the relatively cool of the1950s to the much warmer years of 2009 and 2010.

639-musselmap.jpgMap showing the area of the UBC climate change study. The squares show areas used for “spatial comparison of temperature and zonation.”  The circles  were used for comparison. (Science)

“Rocky intertidal communities are ideal test-beds for studying the effects of climatic warming,” Harley says. “Many intertidal organisms, like mussels, already live very close to their thermal tolerance limits, so the impacts can be easily studied.”

At cooler sites, mussels and rocky shore barnacles were able to live high on the shore and that is well beyond the range of their predators, including the sea star.  As temperatures rose, barnacles and mussels were forced to live at lower shore levels, the same level as predatory sea stars.

Daily high temperatures during the summer months have increased by almost 3.5 degrees Celsius in the last 60 years, causing the upper limits of barnacle and mussels habitats to retreat by 50 centimeters down the shore. However, the effects of predators, and therefore the position of the lower limit, have remained constant.

“That loss represents 51 per cent of the mussel bed. Some mussels have even gone extinct locally at three of the sites I surveyed,” says Harley.

“A mussel bed is kind of like an apartment complex – it provides critical habitat for a lot of little plants and animals,” says Harley. “The mussels make the habitat cooler and wetter, providing an environment for crabs and other small crustaceans, snails, worms and seaweed.”

The study says, “the loss of mussel beds over time has probably resulted  in declines of species richness.”

When pressure from sea star predation was reduced using exclusion cages, the prey species were able to occupy hotter sites where they don’t normally occur, and species richness at the sites more than doubled.

These findings provide a comprehensive look at the effects of warming and predation, while many previous studies on how species ranges will change due to warming assume that species will simply shift to stay in their current temperature range.

Harley says the findings show that the combined effects of warming and predation could lead to more widespread extinction than are currently predicted, as animals or plants are unable to shift their habitat ranges.

“Warming is not just having direct effects on individual species,” says Harley. “This study shows that climate change can also alter interactions between species, and produce unexpected changes in where species can live, their community structure, and their diversity.”

He adds ecological change can only be anticipated if scientists understand the ways various factors “determine the distribution and abundance of species in space and time.”