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
Waste in the water – New purification techniques for healthier aquatic ecosystems
24.07.2018 | Eberhard Karls Universität Tübingen
Plenty of habitat for bears in Europe
24.07.2018 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences