Microclimates may buffer some streams from global warming

Low flows in high country streams this summer. PHOTO BY BOB BERWYN.

Microclimates may partially buffer some streams, at least temporarily, from warming air temperatures. bberwyn photo

‘The one constant is that a healthy watershed will be more resilient to climate change than one that isn’t healthy …’

Staff Report

FRISCO — Global warming is all but sure to raise stream temperatures in many areas, but it turns out that changes in air temperatures don’t offer a reliable proxy for projecting those changes.

Eapecially in the mountains streams of the West, topography and riparian conditions are huge factors in regulating stream temperatures.

The correlation between air temperature and stream temperature is surprisingly tenuous, according to stream ecologists at Oregon State University, who examined historic stream temperature data over a period of one to four decades from 25 sites in the western United States. Continue reading

Global warming threatens freshwater mussels

Freshwater mussels through a microscope.

Freshwater mussels through a microscope. Photo via USGS.

Slight increases in water temperatures may push some mussels into oblivion

By Summit Voice

FRISCO — Global warming may push many native freshwater mussel species to the brink of extinction, according to a new U.S. Geological Survey report. In a laboratory setting, the researchers found that warmer water temperatures impair mussel growth.

Many aquatic biologists see mussels as bellwether species of for climate change impacts.  Freshwater mussels are also good indicators of good water and sediment quality in U.S. rivers. They are also also important in the aquatic food web, filter large amounts of water and suspended particles, and serve as food for other organisms. Continue reading

Can dams help buffer global warming impacts?

Columbia River study shows potential benefits of stored water


This image from the Moderate Resolution Imaging Spectroradiometer (MODIS) shows snowcover for the Columbia River Basin in the Cascade Mountains of Washington State, taken on February 24, 2003 (250 meter resolution). Credit: Jeff Schmaltz MODIS Land Rapid Response Team, NASA/GSFC.

By Summit Voice

FRISCO — For all the environmental mayhem they’ve caused in the past, dams may help buffer some aquatic ecosystems from future global warming impacts, according to a new study from Oregon State University.

Specifically, the researchers said dams could provide “ecological and engineering resilience” to climate change in the Columbia River basin.

“The dams are doing what they are supposed to do, which is to use engineering – and management – to buffer us from climate variability and climate warming,” said Julia Jones, an Oregon State University hydrologist and co-author on the study. “The climate change signals that people have expected in stream flow haven’t been evident in the Columbia River basin because of the dams and reservoir management. That may not be the case elsewhere, however.” Continue reading

Colorado River: New study offers painful details of Glen Canyon Dam impacts to downstream ecosystems


Glen Canyon Dam has fundamentally altered downstream ecosystems in the Colorado River. Photo courtesy U.S. Bureau of Reclamation.

‘A shadow of pre-dam conditions … ‘

By Summit Voice

FRISCO — With all the focus on water quantity in the Colorado River Basin, it’s easy to lose sight of the fact that the installation of massive dams has fundamentally altered the river’s ecosystem.

But an in-depth three-year study done as part of the Glen Canyon Dam Adaptive Management Program offers a stark reminder of the changes wrought by drastically altering the river’s hydrological regime. Continue reading

Biodiversity: Even at ‘safe’ levels, pesticides are having catastrophic impacts on aquatic ecosystems


Dragonflies are taking a big hit from pesticides, even at levels deemed “safe” by lab tests. Bob Berwyn photo.

Study documents dramatic regional decline of insect species

By Summit Voice

SUMMIT COUNTY — After studying ecosystems contaminated with pesticides, scientists say they’ve been able to measure a dramatic loss of invertebrate biodiversity in polluted streams and rivers.

The study is one of the first to document the toxic effects of pesticides at a regional ecosystem level, rather than exptrapolating toxicity from lab tests.

“The current practice of risk assessment is like driving blind on the motorway”, said ecotoxicologist Matthias Liess. “To date, the approval of pesticides has primarily been based on experimental work carried out in laboratories and artificial ecosystems.” Continue reading

BPA shown to confuse fish mating behavior

A red shiner.

Hormone-mimicking chemical could result in inter-species breeding

By Summit Voice

SUMMIT COUNTY — Already pinpointed as a potential health risk to humans, the controversial chemical BPA has now been found to affect the mating choices of fish. potentially leading to inter-breeding of species.

BPA, used in the manufacture of plastic household products, is hormone-mimicking chemical now widely found in aquatic ecosystems across the U.S. The chemical has been banned from baby bottles and childrens’ cups in 11 states. Continue reading

Changing of snowmelt, runoff timing threatens fish

Snake River in Summit County, Colorado.

Earlier snowmelt and runoff in Colorado streams could mean big trouble for fish. PHOTO BY BOB BERWYN.

Changes in runoff timing have been studied for impacts to reservoir operations and diversions, but what about aquatic and riparian ecoystems?

By Bob Berwyn

SUMMIT COUNTY — Earlier snowmelt and runoff in Colorado have been well-documented over the past few years and the finding were reinforced once again in a press release from the U.S. Geological Survey last week.

Water managers are already adjusting reservoir and diversion operations to account for the changes, but there’s been little discussion of the potential impacts to fish and other species that have evolved in tandem with historic streamflow regimes. Continue reading


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