Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study probes ecosystem of tree holes

16.06.2004


’It’s a war inside a tree hole’


It’s war inside a tree hole, says WUSTL ecologist Jamie Kneitel. He has studied the effects of three different parameters on the bug-eat-bug world found in the seemingly innocuous, surprisingly revealing, ecosystem.



If you think your place is a dump, try living in a tree hole: a dark flooded crevice with years of accumulated decomposing leaves and bugs, infested with bacteria, other microbes, and crawling with insect larvae.

A biologist at Washington University in St. Louis has studied the ecosystem of the tree hole and the impact that three factors - predation, resources and disturbance -- have on species diversity.


Jamie Kneitel, Ph.D., Washington University in St. Louis post doctoral researcher in biology in Arts & Sciences, and Jonathan Chase, Ph.D., Washington University assistant professor of biology, found that tinkering with any of those factors changes the make up of the community.

Kneitel uses Shakespeare’s Richard the III reference — "subtle, sly and bloody," Richard III’s mother’s description of her son as a little boy — when talking about the ecosystem he studies. A tree hole can be found in nearly every forest and is an ecosystem surprisingly overlooked by ecologists.

Created by a lost tree branch or deformed trunk, the tree hole collects water, which supports an aquatic community that lets an ecologist like Kneitel address fundamental ecological questions. In this small ecosystem, bugs and leaves fall into this pool of water and decompose, which provides the energy for hundreds of species, including bacteria, protozoa, and mosquito larvae. It’s a generally thriving community where these critters battle each other in a mini-survival-of-the-fittest.

To perform his study, Kneitel recreated the tree hole ecosystem in the laboratory, which allowed him to change the parameters to create different ecological situations. The most common disturbance for a tree hole is lack of water. Resources equate to the food supply, and predation among the three basic organisms - protozoans, rotifers and mosquito larvae - is rampant, and varies depending on resources and disturbance.

"Predators, resources, and disturbances are the most common factors that affect communities, but few studies look at all these factors together," Kneitel said. "Not surprisingly, predators, resources, and disturbances all had really strong effects, but the interesting finding was how these various factors interacted. Community composition was altered by all treatments, depending on which treatments were present. Certain species were associated with each of the treatments - those in predator treatments were those tolerant of predators, those in disturbance treatments were tolerant of disturbances, and so on."

The results will be published in a forthcoming isue of Ecology. The research was supported by the National Science Foundation.

Kneitel studied between 20 and 25 protozoan species and four rotifers; protozoans are single-celled organisms, rotifers, multi-celled, yet some protozoans are bigger than rotifers and will prey upon them. Mosquito larvae browse and filter-feed and will attack either of the groups of species.

’It’s war inside a tree hole," Kneitel said. "We found that predation has the strongest effect when there are no disturbances. Disturbance has the strongest effect when there is little predation. When there is no disturbance or predation, competition is the primary source of extinction. A disturbance — a dry tree hole — pretty much kills everything but certain protozoans that can go dormant and survive the cycle."

Kneitel said most studies of this sort look at two factors, compared with the three he and Chase studied.

"Our results show that if you change any one of the three factors, you alter the face of the community," Kneitel said. "We found that we had a group of species that were good competitors, another that is good at tolerating predators, and yet another that can survive and tolerate disturbances.

"These trait (niche) differences allow many species to coexist with one another at different spatial scales. This is true for this community, but also many other communities work in this way."

Kneitel said the scale of the tree hole system allows him to ask "big picture" questions of ecosystems that can’t be asked on a large scale.

"You can’t really ask these types of questions using long-lived organisms like wolf and deer populations," he said. "It takes years and years to see the effects of predation and disturbance on population dynamics. With these communities, you can do an experiment in a month."

Tony Fitzpatrick | WUSTL
Further information:
http://news-info.wustl.edu/tips/page/normal/891.html

More articles from Life Sciences:

nachricht Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory

nachricht How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>