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 Exciting Plant Vacuoles
14.06.2019 | Julius-Maximilians-Universität Würzburg

nachricht A microscopic topographic map of cellular function
13.06.2019 | University of Missouri-Columbia

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

Im Focus: Tiny light box opens new doors into the nanoworld

Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.

Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...

Im Focus: Cost-effective and individualized advanced electronic packaging in small batches now available

Fraunhofer IZM is joining the EUROPRACTICE IC Service platform. Together, the partners are making fan-out wafer level packaging (FOWLP) for electronic devices available and affordable even in small batches – and thus of interest to research institutes, universities, and SMEs. Costs can be significantly reduced by up to ten customers implementing individual fan-out wafer level packaging for their ICs or other components on a multi-project wafer. The target group includes any organization that does not produce in large quantities, but requires prototypes.

Research always means trying things out and daring to do new things. Research institutes, universities, and SMEs do not produce in large batches, but rather...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Concert of magnetic moments

14.06.2019 | Information Technology

Materials informatics reveals new class of super-hard alloys

14.06.2019 | Materials Sciences

New imaging modality targets cholesterol in arterial plaque

14.06.2019 | Medical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>