Assessing the state of an ecosystem solely on the basis of short-term changes in the number of different species it contains can lead to false conclusions. This is according to a new analysis by an international team including researchers of the Helmholtz Institute for Functional Marine Biodiversity (HIFMB) at the University of Oldenburg and the German Centre for Integrative Biodiversity Research (iDiv). In order to assess ecosystems in a way that is meaningful for nature conservation, experts should instead analyse the turnover of species within a system. The research, based on a mathematical model and environmental data analysis, is published online in the "Journal of Applied Ecology".
A growing number of species are under threat of extinction – in particular due to global environmental changes. Political instruments such as the International Convention on Biological Diversity or the EU's Marine Strategy Framework Directive aim to mitigate this biodiversity crisis.
In practice, taking the number of species (species richness) as a simple metric for determining the state of an ecosystem seems an obvious approach. "But this metric has its pitfalls because it doesn't fully reflect the changes in the system," says the Oldenburg biodiversity expert Hillebrand points out who is also the lead author of the study.
On the contrary, according to the scientists' model calculations, negative influences on an ecosystem do not automatically result in a reduction in species richness. Conversely, the number of species in a system does not automatically increase as soon as an ecosystem recovers from human impact. The reason for this is: "Species richness is a result of the balance between the immigration and the extinction of species."
However, these two processes do not occur at the same speed, Hillebrand explains. A few individuals of a species can quickly migrate into a local habitat and colonise it, but it may take several generations for a species to be replaced by a new, more competitive species, or to die out as a result of changed conditions.
"This means you can't reliably say, on the basis of short-term trends, whether more or fewer species will be left in an ecosystem over a long period of time," Hillebrand stresses, adding: "So species richness can be a false friend."
In their publication the scientists therefore recommend closer monitoring of how many species are migrating into a system, how many are leaving it, and how many species are becoming more or less abundant within the system. As an example the scientists used this method to analyse long-term measurements from various ecosystems - such as data on drifting microalgae (phytoplankton) from the mud flats of the Dutch Wadden Sea and the lakes of North America, as well as data from grassland ecosystems on six different continents.
“In extreme cases, the majority of species in an ecosystem could be replaced by new species. But if you only look at the number of species, the so-called species richness, that number doesn’t change at all”, says Prof. Dr. Jonathan Chase of the German Centre for Integrative Biodiversity Research (iDiv) and the Martin Luther University Halle-Wittenberg. “Therefore, species richness alone can be a misleading metric and can obscure what is really going on in an ecosystem.”
For their analyses the researchers explicitly used data gathered by conservationists in environmental monitoring programmes. In this way the scientists want to ensure that their tool can be used with the available resources, which in practice are often limited. "We hope that in this way we can build a bridge between the basic research and nature conservation in practice," Hillebrand says.
Publication: Helmut Hillebrand, Bernd Blasius et al. (2017). Biodiversity change is uncoupled from species richness trends – consequences for conservation and monitoring. Journal of Applied Ecology. DOI: 10.1111/1365-2664.12959
Dr. Corinna Dahm-Brey | idw - Informationsdienst Wissenschaft
Minimized water consumption in CSP plants - EU project MinWaterCSP is making good progress
05.12.2017 | Steinbeis-Europa-Zentrum
Jena Experiment: Loss of species destroys ecosystems
28.11.2017 | Technische Universität München
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications
Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...
Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.
The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
11.12.2017 | Physics and Astronomy
11.12.2017 | Earth Sciences
11.12.2017 | Information Technology