Ecosystems

Urban expansion could greatly increase flood risks
March 5, 2015 02:07 PM - Texas A&M University

A heads-up to New York, Baltimore, Houston and Miami: a new study suggests that these metropolitan areas and others will increase their exposure to floods even in the absence of climate change, according to researchers from Texas A&M University. The study presents first-ever global forecasts of how the exposure of urban land to floods and droughts may change due to urban expansion in the near future. In 2000, about 30 percent of the global urban land (over 75,000 square miles) was located in the high-frequency flood zones; by 2030, this will reach nearly 40 percent (280,000 square miles) as the global urban land grows from 250,000 square miles to 720,000 square miles, the authors say.

University of Oxford finds trees inhale less carbon when they are drought - impacted
March 5, 2015 07:34 AM - University of Oxford

For the first time, an international research team has provided direct evidence of the rate at which individual trees in the Amazonian basin 'inhale' carbon from the atmosphere during a severe drought. 

The researchers measured the growth and photosynthesis rates of trees at 13 rainforest plots across Brazil, Peru and Bolivia, comparing plots that were affected by the strong drought of 2010 with unaffected plots. They found that while growth rates of the trees in drought-affected plots were unchanged, the rate of photosynthesis – by which trees convert carbon into energy to fuel their activities – slowed down by around 10 percent over six months. Their paper, published in the journal, Nature, concludes that trees may be channelling their more limited energy reserves into growth rather than maintaining their own health. Computer simulations of the biosphere have predicted such responses to drought, but these are the first direct observations of this effect across tropical forests.  

Amazon deforestation 'threshold' causes species loss to accelerate
March 4, 2015 03:32 PM - University of Cambridge

One of the largest area studies of forest loss impacting biodiversity shows that a third of the Amazon is headed toward or has just past a threshold of forest cover below which species loss is faster and more damaging. Researchers call for conservation policy to switch from targeting individual landowners to entire regions.

Combined Arctic ice observations show decades of loss
March 3, 2015 10:14 AM - University of Washington via EurekAlert!

It's no surprise that Arctic sea ice is thinning. What is new is just how long, how steadily, and how much it has declined. University of Washington researchers compiled modern and historic measurements to get a full picture of how Arctic sea ice thickness has changed. The results, published this month in The Cryosphere, show a thinning in the central Arctic Ocean of 65 percent between 1975 and 2012. September ice thickness, when the ice cover is at a minimum, is 85 percent thinner for the same 37-year stretch.

Some plants "prefer" certain pollinators and respond to them!
March 3, 2015 07:19 AM - Oregon State University

Rather than just waiting patiently for any pollinator that comes their way to start the next generation of seeds, some plants appear to recognize the best suitors and “turn on” to increase the chance of success, according to a new study published this week.

Being picky may increase access to genetic diversity and thus give the plants a competitive advantage over their neighbors, but there is a risk, the researchers say. If the preferred pollinators decline for any reason, the plants may not reproduce as easily and could decline as well.

How did Emperor Penguins survive the last ice age?
March 2, 2015 07:00 AM - University of Oxford

The study of how climate change has affected emperor penguins over the last 30,000 years found that only three populations may have survived during the last ice age, and that the Ross Sea in Antarctica was likely the refuge for one of these populations.

The findings, published in the journal Global Change Biology, suggest that while current climate conditions may be optimal for emperor penguins, conditions in the past were too extreme for large populations to survive.

In California, Beavers are essential to recovering wild salmon
March 1, 2015 04:35 PM - Miria Finn / onEarth, The Ecologist

With California's wild Coho salmon populations down to 1% of their former numbers, there's growing evidence that beavers - long reviled as a pest of the waterways - are essential to restore the species, writes Maria Finn. In the process, they raise water tables, recharge aquifers and improve water quality. What's not to love?

Beavers are the single most important factor in determining whether Coho salmon persist in California. They work night and day, don't need to be paid, and are incredible engineers.

Using satellites to monitor forest health
February 28, 2015 07:12 AM - Oregon State University

Scientists for the first time have simultaneously compared widespread impacts from two of the most common forest insects in the West – mountain pine beetle and western spruce budworm – an advance that could lead to more effective management policies.

By combining data from satellites, airplanes and ground-based crews, the researchers have shown in unprecedented detail how insects affect Western forests over decades.

In the past, forest managers relied on airplane surveys to evaluate insect damage over broad areas.

Why the sun impacts climate more during cooler periods
February 27, 2015 04:08 PM - Aarhus University via EurekAlert!

The activity of the Sun is an important factor in the complex interaction that controls our climate. New research now shows that the impact of the Sun is not constant over time, but has greater significance when the Earth is cooler. There has been much discussion as to whether variations in the strength of the Sun have played a role in triggering climate change in the past, but more and more research results clearly indicate that solar activity - i.e. the amount of radiation coming from the Sun - has an impact on how the climate varies over time.

Is Greenland Melting?
February 26, 2015 04:09 PM - University of Copenhagen

A team of scientists lead by Danish geologist Nicolaj Krog Larsen have managed to quantify how the Greenland Ice Sheet reacted to a warm period 8,000-5,000 years ago. Back then temperatures were 2-4 degrees C warmer than present. Their results have just been published in the scientific journal Geology, and are important as we are rapidly closing in on similar temperatures.

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