Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New model for studying species distributions and the mid-domain effect developed

11.07.2005


Understanding why some parts of the world sustain more species than others is one of the most enigmatic problems in ecology. One particularly common pattern is a "hump-shaped" biodiversity gradient: for example, biodiversity peaks near the equator and declines going either north or south.



Historically, explanations for such gradients invoked coincident geographical variation in environmental factors hypothesized to reduce extinction rates or promote the evolution of new species.

Recently, however, random re-arrangements ("randomizations") of species’ distributions in geographical space have been shown to reproduce these hump-shaped gradients (termed "mid-domain effects").


Because randomizations do not explicitly include environmental factors, some have argued that such factors may be less important for biodiversity than previously thought. However, randomization analyses are controversial: critics argue that they are devoid of any ecological processes (not just environmental gradients), and thus have no explanatory utility.

Addressing this criticism requires models that make explicit biological assumptions about how species’ distributional limits are determined, consistent with a particular hypothesized cause of biodiversity gradients.

In an article in the July 2005 issue of The American Naturalist, Sean R. Connolly (James Cook University) develops a general framework for such models and analyzes specific models that omit roles for variation in the quality of environmental conditions.

Under a very general set of conditions, these models are shown to produce mid-domain effects. These are qualitatively similar in shape, but of substantially lower magnitude, compared to randomization analyses. These results reveal that the mid-domain effect is likely to be a real phenomenon, and thus cannot be ignored, but that comparing real biodiversity patterns to those produced by randomizations may be misleading. They also identify an alternative way forward: formulating process-oriented models of species distributions and testing them directly against empirical data.

Carrie Olivia Adams | EurekAlert!
Further information:
http://www.uchicago.edu

More articles from Life Sciences:

nachricht How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>