Organic agriculture boosts biodiversity on farmlands

Does organic farming foster biodiversity? The answer is yes, however, the number of habitats on the land plays an important role alongside the type and intensity of farming practices. These are the findings of an international study that looked at ten regions in Europe and two in Africa. The results has been published in Nature Communications. The study shows that even organic farms have to actively support biodiversity by, for example, conserving different habitats on their holdings.

An international team, including scientists from Technische Universität München (TUM), investigated the contribution of organic farming to supporting farmland biodiversity between 2010 and 2013. Researchers wanted to explore whether organic farms are home to more species than their conventional neighbors. The team used uniform methods across Europe to capture data and analyze it to establish the impact of farming methods and intensity and of landscape features on biodiversity.

"Organic farming is beneficial to the richness of plant and bee species. However, observed benefits concentrate on arable fields," says TUM's Prof. Kurt-Jürgen Hülsbergen. His Chair for Organic Agriculture and Agronomy analyzed 16 Bavarian dairy farms.

The study investigated farms in twelve regions with different production systems. In each region, farms were selected randomly, half of them certified organic for at least five years. In Switzerland, grassland-based cattle farms were studied and in Austria the study looked at arable farms. In Italy and Spain, researchers focused on farms with permanent crops such as wine and olives, and on small-scale subsistence farms in Uganda.

More species because of field boundaries

More species were found in organic arable fields than in non-organic fields. In contrast, there was little difference in grasslands or vineyards. Organic farming benefited the four taxonomic groups of plants, earthworms, spiders and bees -- which were sampled as surrogates for the multitude of creatures living on farmland -- in different ways. In general, more species of plants and bees were found on organic than on non-organic fields, but not more species of spiders and earthworms.

If types of field boundaries such as grass verges or hedges were included in the comparison, the difference between organic and non-organic decreases. "Obviously, most species found in fields on organic farms tend to be concentrated in boundary areas on non-organic farms. There was little difference in the total number of species on the farms," explains Max Kainz, who headed the sub-project at TUM. The occurrence of rare or threatened species did not increase on organic farms, according to Kainz.

Even organic farms need to increase habitats

To sustain farmland biodiversity, which is currently under grave threat, researchers have identified complement organic farming methods with dedicated efforts to conserve habitats. To increase the number of habitats, the authors of the study recommend adding structural elements, such as woods, grass verges and fallow land, to farms. "Surprisingly, viewed across all regions, we did not find a higher number of natural habitats on organic farms than non-organic farms," reports Kainz.

"However, it was clear that habitat diversity is the key to species diversity," adds Prof. Hülsbergen. He continues: "The results of the study underline the importance of maintaining and expanding natural landscape features -- something that the EU's Greening Program has been trying to accomplish." If these additional habitats are different to the rest of the farm, for example hedges in grassland farms or herbaceous strips in arable farms, they have a huge impact on the biodiversity of a farm.

Source: Sciencedaily.com

Tsunami Sensor Detects Mysterious Background Signal in Panama

ScienceDaily (June 3, 2011) — An unusual signal detected by the seismic monitoring station at the Smithsonian Tropical Research Institute's research facility on Barro Colorado Island results from waves in Lake Gatun, the reservoir that forms the Panama Canal channel, scientists report. Understanding seismic background signals leads to improved earthquake and tsunami detection in the Caribbean region where 100 tsunamis have been reported in the past 500 years.

As part of a $37.5 million U.S. presidential initiative to improve earthquake monitoring following the devastating tsunami in the Indian Ocean in 2004, a seismic sensor was installed on Barro Colorado Island in 2006. The sensor is one of more than 150 sensors that comprise the U.S. Geological Survey's Global Seismographic Network.

Barro Colorado Island is a hilltop that was isolated by the waters of the reservoir created when the Chagres River was dammed to form Lake Gatun, a critical part of the Panama Canal. The Barro Colorado seismic monitoring station is a collaboration between the U.S. Geological Survey, the U.S. National Oceanic and Atmospheric Administration, the University of Panama and STRI.

Ultra-sensitive devices at the station pick up a large range of ground motion from felt earthquakes to nanometer-scale seismic background noise. The instruments at the station include very sensitive broadband seismometers used to detect distant earthquakes and low-gain accelerometers that measure ground movement and withstand violent local earthquakes and explosions.

The sensors detect signals from many different sources that include cars, boats and machinery operating up to several kilometers away. They also pick up the background "hum of the Earth" caused by ocean waves breaking on continental shelves around the world.

Scientists noticed that sensors on Barro Colorado recorded an intriguing wave pattern at an intermediate frequency. They suspected that this pattern could be caused by standing waves in Lake Gatun. Standing waves, also known as "seiches," are common in enclosed bodies of water like lakes and harbors where waves moving in opposite directions interact. By installing a water-level detection meter along the shoreline, researchers confirmed that changes in the water level of the lake correspond to the unusual seismic signal.

This is not the first report of seiches in Lake Gatun. Earlier reports correlated the release of methane gasses in the sediments below the canal to seiches and bottom currents in the lake. The Panama Canal Authority provided data about the depth of the Canal channel and of Lake Gatun that the authors used to model wave patterns in the lake.

Boat traffic and wind speed correlate with the unusual wave pattern, which was more common during the day than it was at night, but more information is needed to confirm what is actually causing the waves.

This report, published in the Journal of Geophysical Research, provides a new method to quantify the impact of water movements as recorded by land-based seismometers. A more exact understanding of the seismic signals resulting from water movements will improve estimates of other phenomena like tsunami impacts.

Source: Sciencedaily.com

Octopuses Make Some Pretty Good Moves

ScienceDaily — In case you thought that octopuses were smart only in guessing the outcome of soccer matches (remember the late Paul the octopus in Germany who picked all the right winners in last year's world cup matches in Johannesburg?), scientists at the Hebrew University of Jerusalem have now shown that not only are they smart, they can make some pretty good moves as well.

Octopuses are among the most developed invertebrates. They have large brains and are fast learners. With eight arms and no rigid skeleton, they perform many tasks like crawling, swimming, mating and hunting. And unlike most animals such as humans -- who are restricted in their movements by a rigid skeleton which helps in determining the position of their limbs -- octopuses have limitless flexibility.

But because they have no such rigid structure, it was believed that the octopuses have only limited control over their eight flexible limbs. However, the Hebrew University researchers have shown otherwise. They developed a three-choice, transparent, plexiglass maze that required the octopus to use a single arm and direct it to a visually marked compartment outside of its tank of water that contained a food reward.

The octopuses in the experiment learned to insert a single arm through a central tube, out of the water, and into the correct marked goal compartment to retrieve the food reward. This success was dependent on visual information, which the octopuses were able to translate into a series of coordinated movements made by a single arm and retrieve the food. They were also able to repeat this process.

The completion of this task shows for the first time that an octopus can direct a single arm in a complex movement to a target location. Motor control issues, such as this, are the basis of an ongoing European Union research project aimed at building a "robot octopus." To understand how the octopus controls its movements, and to what extent it controls them, is therefore an important base for the design of the control architecture of a robot devoid of a rigid skeleton.

The research was reported on in a recent edition of Current Biology, and was authored by Tamar Gutnick, Prof. Binyamin Hochner and Dr. Michael Kuba of the Interdisciplinary Center for Neural Computation at the Alexander Silberman Institute of Life Sciences at the Hebrew University, and Dr. Ruth A. Byrne of the Medical University of Vienna, Austria.

Source: Sciencedaily.com