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Pointing the way to pine beetle control, but at what cost?

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Pine beetle-killed trees in Summit County, Colorado.

Dartmouth scientists study pine beetle population dynamics

By Summit Voice

SUMMIT COUNTY — Dartmouth scientists say they may have found a pathway to keeping pine beetles in check, showing that their populations fluctuate between extremes, with no middle ground.

“That is different from most species, such as deer, warblers and swallowtail butterflies, whose populations tend to be regular around some average abundance based on food, weather, and other external factors,” said Matt Ayres, a professor in the Department of Biological Sciences at Dartmouth and senior author on the paper. “They don’t appear and disappear in cycles. Rather, they exist in two stable equilibrium states—one of high abundance and the other of scarcity.”

Once the population pendulum swings toward the high end, it won’t quickly or easily swing back, Ayres explained.

According to the new study, forest managers might be able to keep pine beetle populations at the low end of the scale by boosting competitor and predator beetle populations — but they don’t address how that could affect the overall equilibrium of forest ecosystems, especially those where older trees need a change agent like bark beetles to spur regeneration. Continue reading

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Study: High school science teachers weak on evolution

More refreshers courses needed, Penn State researchers say

Many high school science teachers failing when it comes to teaching evolutionary science.

By Summit Voice

SUMMIT COUNTY — High school biology teachers are only lukewarm when it comes to teaching evolutionary biology, despite 40 years of court rulings that teaching creationism or intelligent design violates the Constitution, according to Penn State political scientists. A mandatory undergraduate course in evolutionary biology for prospective teachers, and frequent refresher courses for current teachers, may be part of the solution, they say.

“Considerable research suggests that supporters of evolution, scientific methods, and reason itself are losing battles in America’s classrooms,” said Michael Berkman and Eric Plutzer, professors of political science at Penn State, in today’s (Jan. 28) issue of Science. Continue reading

More bad news on ‘gender-bending’ water pollutants

UK study shows significant impact to fish reproduction from endocrine disrupting chemicals.

New study shows estrogen from various sources is impacting fish in UK rivers

By Summit Voice

SUMMIT COUNTY — More research from the UK is showing that remnant chemicals from birth control pills, hormone therapy drugs, plastics manufacturing and other sources — collectively known to contain endocrine disrupting chemicals — are bending the gender of fish.

The new study, led by the universities of Exeter and Brunel, shows those chemicals can have a significant impact on the ability of fish to breed in UK Rivers.

“This is the first time we’ve seen firm evidence that the intersex fish, males that have been feminised by EDCs, have a reduced ability to breed,” said Charles Tyler, from the University of Exeter‘s Biosciences department. “Clearly this raises concerns about the implications on the future for wild fish populations living in UK rivers, but there’s also much wider issues raised by these findings. Some of the effects seen in fish could occur in other animals too as hormone systems are quite similar across all vertebrates.

“EDCs have been tentatively linked with human health impacts too, including, falling sperm counts and cardio-vascular disease. These findings remain more controversial,” Prof Tyler added. “In contrast, we have shown, unequivocally that environmental estrogens alter sexual development in fish and now, through this study, that this can impact on their ability to breed.” Continue reading

Morning photo: Montane zone

Scruffy mid-elevation habitat harbors hidden treasures

The tip of a willow branch, where a water droplet conceals a tiny insect. When the pussy willows start to show, you can start to at least think about the end of winter. Our willow areas often mark the boundary between wetlands and dry uplands and represent crucial wildlife habitat.

SUMMIT COUNTY — In between the spectacular high mountain meadows and the verdant riparian corridors is the montane zone,with the roughest and scruffiest vegetation. Plants living here have to adapt to wide range of temperatures, both seasonally and in the span of single day. They also have to be able to thrive in dry winds, periods of intense rainfall and everything in between. But this is the zone where the majority of life — including human life — happens, and there is an astounding variety of shrubs, flowering plants and grasses. More after the break … Continue reading

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