The article summarizes bird survey results from the world's largest and longest running experimental study of forest fragmentation – the Biological Dynamics of Forest Fragments Project, sponsored by the Smithsonian Tropical Research Institute, the Smithsonian Institution and the National Institute for Amazon Research, in Brazil.
Fragmentation shrinks the Amazon forest by thousands of square kilometers every year, leaving a trail of small forest fragments isolated by cleared land. Many species that occur in intact forest prior to destruction will not be present in a small fragment, but would they be found in an equally small plot surrounded by untouched forest? The answer to this question has profound management implications because it weights the relative importance of area and isolation in the design of forest reserves.
The team, headed by Gonçalo Ferraz from the National Institute for Amazon Research in Brazil, has been studying a 13-year data set of more than 40,000 bird captures in 23 isolated and non-isolated plots of forest, ranging from 1 to 600 hectares. Richard Bierregaard, Jr. and Philip Stouffer led the data collection as part of the experimental study founded by Thomas Lovejoy and his Brazilian colleagues. The most striking result is that the effects of area on the occurrence of bird species are much stronger than the effects of isolation.
"It is no surprise that small isolated fragments lack many species" said Ferraz. "Many birds are so uncommon that they will rarely occur in small plots even in the middle of vast undisturbed forest." The question is, does isolation aggravate this pervasive effect of size. It does for many species, but surprisingly not for many others.
The main methodological difficulty of this study, say the authors, was that birds are hard to detect. When one samples a plot of forest it is easy to miss species that actually exist there. To distinguish real absences from detection failures, the authors used state of the art statistical methods developed by James Nichols and colleagues, at the U.S. Geological Survey's Patuxent Wildlife Research Center.
"With a handle on the detection problem it is much easier to understand real species occurrence", said Nichols, "and looking at occurrence through time, one understands the dynamics of species faced by forest destruction". Some vanish because they don't survive in a given site, others because they don't colonize new sites that become available. The two processes may also act in combination, but different species follow different ways.
The detailed treatment of the dynamics of 55 bird species allowed an unprecedented test of classical scientific hypotheses about the effects of reserve size and isolation on the local extinction and colonization of species. The species-specific estimates of effects of area and isolation on extinction and colonization processes permit prediction of effects of future fragmentation on bird communities in these Amazon landscapes.
Area is important because the forest is spatially diverse. "What might look like a vast mantle of homogeneous green is actually a multicolored mosaic", said Lovejoy. And species that occur throughout the forest at the large scale actually may have very specific requirements at the fine scale.
Large areas of forest encompass a wide enough variety of local conditions – and species, to ensure the survival of the Amazon and its inhabitants. In December, 2006, the Brazilian government established the largest protected area ever, 15 million hectares in Northern Brazil. Sustainable conservation strategies result when policy is based on sound science. The results in this paper confirm the importance of this action and other, similar efforts to conserve forested regions.
Upcycling 'fast fashion' to reduce waste and pollution
03.04.2017 | American Chemical Society
Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
26.04.2017 | Materials Sciences
26.04.2017 | Agricultural and Forestry Science
26.04.2017 | Physics and Astronomy