At the Department of Ecology of the University of Barcelona, Salvador Pueyo has developed some new instruments that may provide new insights into their characterization. In its 22 September issue, the journal Science published a technical comment in which Pueyo and Roger Jovani of the Estación Biológica de Doñana (CSIC) apply these new methods to a re-analysis of data from an article on coffee plantation pests published in Science the previous February, which had used mainstream techniques. The application of the new methodology brings about significant changes in the results.
The ecologist Ramon Margalef noted that catastrophic events of many different types reveal the same hidden order. Take the case of wildland fires in Catalonia. Roughly, for every three fires of a given size, there is one that is twice as large, and for every three fires as large as this one, there is one two times larger, and so on, up to a maximum size. This is called a power law. It follows that the great majority of fires are tiny, but 0.43% of fires burn 75% of the affected area. Currently, our understanding of how power laws arise is severely limited. At the Department of Ecology at the UB, Salvador Pueyo has been developing a statistical procedure able to analyse the data.
Scale insects are common pests in several kinds of crops. These bizarre insects live by sticking to plants and sucking their sap. There are species of ants that act as shepherds for scale insects, protecting them from their predators and “milking” them to obtain a nutritive fluid. In a paper published in Science, ecologists John Vandermeer and Ivette Perfecto of the University of Michigan used mainstream methods to analyse the variability in scale insect densities in different coffee plants in a coffee plantation in Chiapas. They concluded that scale insect densities conform to a power law, but that the power law breaks down under the action of ants. They also gave an explanation for the power law.
Pueyo and Jovani re-analysed Vandermeer and Perfecto’s data with new procedures, which give a much clearer image of the power law. Pueyo and Jovani confirmed that scale insect densities do indeed display a power law, but rejected the supposition that the law breaks down in the presence of ants. The effect of the ants is not qualitative: it is just quantitative. Without ants, for every ten plants with a given scale insect density there is one with twice that density. With ants, for every four plants with a given density we find one with twice that density. In addition, the maximum density is ten times larger in the latter case. Even more importantly, the data themselves refute the mechanism for the origin of the power law postulated by Vandermeer and Perfecto. Pueyo and Jovani propose a more credible mechanism, which may well help improve the management of this pest.
Pueyo stresses that there is nothing wrong in Vandermeer and Perfecto’s paper. He considers that their starting point is imaginative and that the line of research is particularly interesting. The only problem is that the authors used the same type of tools that everybody uses. Pueyo and Jovani’s study is not meant as a criticism of the work of two specific authors, but as a demonstration of the potential that the new methods open up for a general improvement in this kind of research.
In another article published in Science last year other researchers from the UB’s Department of Ecology showed that of all Europe’s regions the Mediterranean is the one that is most vulnerable to climate change. Scientists forecast an intensification of wildland fires and other catastrophic events. Therefore, it is important to increase our ability to obtain projections for these phenomena. For Pueyo, “current projections provide more than enough data for designing decisive action to avert disasters. The Kyoto Protocol is just a minor step; surprisingly, Spain is one of the major beneficiaries of the treaty and one of the countries that is furthest away from fulfilling it”.
Rosa Martínez | alfa
Species may appear deceptively resilient to climate change
24.11.2017 | University of California - Davis
Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University
High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons
The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
24.11.2017 | Earth Sciences
24.11.2017 | Ecology, The Environment and Conservation
24.11.2017 | Earth Sciences