Ecologists studying biodiversity and conservationists preserving habitats have asked these questions for more than 50 years, but with limited and imprecise means to answer them. Now a team of NASA-funded researchers has completed an experiment to remotely sense and predict where certain birds are most likely to live and breed.
In the late 1950s, Princeton University ecologist Robert MacArthur proposed that bird species choose their habitat according to the structure of a forest – that is, the tree canopy height, branching structure, leaf spread and abundance, and the presence of low-lying shrubs.
To determine the habitat where particular species bred, ornithologists trekked deep into forests and used everything from binoculars to suspended vines to observe leaves and twigs and extrapolate the make-up of forest areas. They could spend thousands of painstaking hours analyzing plots as small as 100 square feet. As recently as May 2010, an Oregon State University doctoral student dislocated her shoulder while using a rudimentary pole to demonstrate how scientists once measured tree branches from the ground -- and to show how and why the science of studying birds has changed.
"Most of the time, the data weren't very good, and didn't cover broad areas of land," said landscape ecologist Matt Betts, an assistant professor at Oregon State University in Corvallis.
A research team led by Scott Goetz of the Woods Hole Research Center in Falmouth, Mass., has helped bring habitat sensing into the 21st century. The researchers combined satellite data, a ground-based bird census, light detection and ranging (lidar), and a new modeling technique to correctly predict the presence of songbirds in a forest. Their results were published this week in the journal Ecology.
"The study of bird habitats has entered a new era," said Goetz. "Until recently, predicting bird habitat was limited. We've known for many years that the composition of trees and shrubs determines habitat quality, which in turn influences a species' presence and population density. But this study uses remote sensing to accurately predict which habitats birds prefer to use year after year, over many square miles of complex terrain."
According to Goetz, NASA's Laser Vegetation Imaging Sensor (LVIS, pronounced Elvis), was key to the team's success. The instrument sends pulses of laser light down from an airplane toward the forest canopy and records the points at which signals bounce back from leaves, branches, and land surfaces. Goetz and colleagues analyzed the data to confirm things like canopy height – the difference between the top of a tree and the ground – and the top-to-bottom density of tree canopies.
"We're doing the same thing our predecessors did, but in much more detail and over a much broader area," said Betts. "We have new metrics now that just weren't possible before."
When combined with data from the NASA-built Landsat satellite – which can indicate seasonal changes in the amount of vegetation -- the LVIS data indicated not only the height of the trees but whether they have mostly high branches or lots of canopy layers beneath tree tops.
For the study published this month, the team made field observations of the Black-throated Blue Warbler, a small songbird that prefers lower-lying vegetation. Using four years of LVIS data, the researchers ranked various forest habitats as good, fair, or poor based on canopy structure. Their "good" rankings for the warbler matched actual ground data -- showing the actual presence of the species in each habitat -- 90 percent of the time.
"For predicting species across broad landscapes over time, this lidar technology is incredibly valuable," said Betts, a co-author of Goetz's study. "We can now conduct higher-quality estimates of the relative importance of climate versus habitat structure in affecting animal populations.". And this technique should transfer to predictions of other animals whose habitats are associated with canopy structure, like flying squirrels or martens. If we can track downed logs on the forest floor, we could even model habitats for salamanders."
Sarah DeWitt | EurekAlert!
Scientists produce a new roadmap for guiding development & conservation in the Amazon
09.12.2016 | Wildlife Conservation Society
Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine