The Eco News Roundup brings stories and commentary about issues related to climate change, renewable energy and the environment.
The stability of the Amazon rainforest, and the ecosystem’s resilience to widespread deforestation, may be much lower than previously thought. The replacement of stands of trees with grassland changes evapotranspiration rates and atmospheric moisture convergence, which in turn reduce regional rainfall, a feedback effect that could drive further deforestation. Previous research indicated that a dramatic shift from forest to grassland could overtake the Amazon when the total deforested area hits 40 to 50 percent of the forest’s current size. New research by Pires and Costa, however, find that the deforestation needed to trigger this equilibrium shift is much lower, closer to just 10 percent.
Despite the size and severity of the massive 2007 Anaktuvuk River fire on Alaska’s North Slope, much of the arctic vegetation has recovered and the tundra is likely to return to its pre-fire condition according to University of Alaska Fairbanks scientist Syndonia “Donie” Bret-Harte and colleagues in a recent scientific paper.
In April 2007, a wall of smoke was visible 23 miles south of the fire at the UAF Institute of Arctic Biology Toolik Field Station where Bret-Harte, co-authors and other scientists had several arctic research projects underway. Tundra fires on the North Slope are historically rare events and, as they watched the smoke, they recognized an important research opportunity was unfolding.
“Most tundra fires are small and go out quickly,” said Bret-Harte, a plant ecologist at IAB. “They are usually ignited by lightning and burn with very light severity, but this was clearly different.”
Sea-level rise (SLR) has been isolated as a principal cause of coastal erosion in Hawaii. Differing rates of relative sea-level rise on the islands of Oahu and Maui, Hawaii remain as the best explanation for the difference in island-wide shoreline trends (that is, beach erosion or accretion) after examining other influences on shoreline change including waves, sediment supply and littoral processes, and anthropogenic changes. Researchers from the University of Hawaii – Manoa (UHM), School of Ocean and Earth Science and Technology (SOEST) and the State of Hawaii, Department of Land and Natural Resources published a paper recently showing that SLR is a primary factor driving historical shoreline changes in Hawaii and that historical rates of shoreline change are about two orders of magnitude greater than SLR.
WASHINGTON – Building on President Obama’s Climate Action Plan, which calls for steady, responsible steps to reduce carbon pollution, the Energy Department today broke ground on the nation’s largest federally-owned wind project at the Pantex Plant in Amarillo, Texas. Once completed, this five-turbine 11.5 megawatt project will power more than 60 percent of the plant with clean, renewable wind energy and reduce carbon emissions by over 35,000 metric tons per year – equivalent to taking 7,200 cars off the road. The Pantex Plant is the primary site for the assembly, disassembly, and maintenance of the United States’ nuclear weapons stockpile.
Under the Obama Administration, federal agencies have reduced greenhouse gas emissions by more than 15 percent – equivalent to permanently taking 1.5 million cars off the road. To build on this accomplishment, the Administration has established a new goal: the federal government will consume 20 percent of its electricity from renewable sources by 2020 – more than double the current goal of 7.5 percent.
Scientists studying the decline and recovery of seagrass beds in one of California’s largest estuaries have found that recolonization of the estuary by sea otters was a crucial factor in the seagrass comeback. Led by researchers at the University of California, Santa Cruz, the study will be published in the Proceedings of the National Academy of Sciences the week of August 26. Seagrass meadows, which provide coastal protection and important habitat for fish, are declining worldwide, partly because of excessive nutrients entering coastal waters in runoff from farms and urban areas. The nutrients spur the growth of algae on seagrass leaves, which then don’t get enough sunlight. In Elkhorn Slough, a major estuary on California’s central coast, algal blooms caused by high nutrient levels are a recurring problem. Yet the seagrass beds there have been expanding in recent years.
By carefully analyzing a 150-year-old moss bank on the Antarctic Peninsula, researchers reporting in Current Biology, a Cell Press publication, on August 29 describe an unprecedented rate of ecological change since the 1960s driven by warming temperatures. “Whilst moss and amoebae may not be the first organisms that come to mind when considering Antarctica, they are dominant components of the year-round terrestrial ecosystem in the small ice-free zones during an austral summer,” says Jessica Royles of the British Antarctic Survey and the University of Cambridge. “We know from meteorological measurements and from the interpretation of signals preserved within ice and sediment cores that the climate of the Antarctic Peninsula has undergone substantial and rapid change. Our evidence, from the southernmost known moss bank, exploits an unusual biological archive and shows that the flora and fauna of the Antarctic Peninsula are very sensitive and have in the past responded, and continue to respond, to these changes in climate.”
In the 1970s, red spruce was the forest equivalent of a canary in the coal mine, signaling that acid rain was damaging forests and that some species, especially red spruce, were particularly sensitive to this human induced damage. In the course of studying the lingering effects of acid rain and whether trees stored less carbon as a result of winter injury, U.S. Forest Service and University of Vermont scientists came up with a surprising result — three decades later, the canary is feeling much better. Decline in red spruce has been attributed to damage that trees sustain in winter, when foliage predisposed to injury by exposure to acid rain experiences freezing injury and dies. Paul Schaberg, a research plant physiologist with the U.S. Forest Service’s Northern Research Station in Burlington, Vt., and partners studied red spruce trees in Vermont, New Hampshire and Massachusetts. They found that the influence of a single damaging winter injury event in 2003 continued to slow tree growth in New England for 3 years, longer than had been expected, and had a significant impact on carbon storage.
They also found something they did not expect.
In the Midwest, some people have a fear of encountering snapping turtles while swimming in local ponds, lakes and rivers. Now in a new study, a University of Missouri researcher has found that snapping turtles are surviving in urban areas as their natural habitats are being polluted or developed for construction projects. One solution is for people to stop using so many chemicals that are eventually dumped into the waterways, the scientist said.
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