Forest ecologists have long sought to understand why so many different species of trees can coexist in the same niche. A modeling study is now providing clues.
Forests, especially tropical forests, are home to thousands of species of trees—sometimes tens to hundreds of tree species in the same forest—a level of biodiversity ecologists have struggled to explain.
© Dariush M | Shutterstock
In a new study published in the journal Proceedings of the National Academy of Sciences (PNAS), researchers at the International Institute for Applied Systems Analysis (IIASA) and their colleagues in Australia are now providing a first model that elucidates the ecological and evolutionary mechanisms underlying these natural patterns.
“Forests in particular and vegetation in general are central for understanding terrestrial biodiversity, ecosystem services, and carbon dynamics,” says IIASA Evolution and Ecology Program Director Ulf Dieckmann. Forest plants grow to different heights and at different speeds, with the tallest trees absorbing the greatest amounts of sunlight, and shorter trees and shrubs making do with the lower levels of sunlight that filter through the canopy.
These slow-growing shade-tolerant species come in an unexpectedly large number of varieties—in fact, far more than ecological models have been able to explain until now.
Traditional ecological theory holds that each species on this planet occupies its own niche, or environment, where it can uniquely thrive. However, identifying separate niches for each and every species has been difficult, and may well be impossible, especially for the observed plethora of shade-tolerant tropical trees. This raises the fundamental question: are separate niches really always needed for species coexistence?
In the new study, the researchers combined tree physiology, ecology, and evolution to construct a new model in which tree species and their niches coevolve in mutual dependence. While previous models had not been able to predict a high biodiversity of shade-tolerant species to coexist over long periods of time, the new model demonstrates how physiological differences and competition for light naturally lead to a large number of species, just as in nature.
At the same time, the new model shows that fast-growing shade-intolerant tree species evolve to occupy narrow and well-separated niches, whereas slow-growing shade-tolerant tree species have evolved to occupy a very broad niche that offers enough room for a whole continuum of different species to coexist—again, just as observed in nature.
Providing a more comprehensive understanding of forest ecosystems, the resulting model may prove useful for researchers working on climate change and forest management. Dieckmann says, “We hope this work will result in a better understanding of human impacts on forests, including timber extraction, fire control, habitat fragmentation, and climate change.”
The study was led by Daniel Falster at Macquarie University in Australia, who was a participant in the 2006 IIASA Young Scientists Summer Program.
Falster DS, Brännström Å, Westoby M, Dieckmann U (2017). Multi-trait successional forest dynamics enable diverse competitive coexistence. Proceedings of the National Academy of Sciences (PNAS). doi: 10.1073/pnas.1610206114.
Katherine Leitzell | idw - Informationsdienst Wissenschaft
Filling intercropping info gap
16.11.2017 | American Society of Agronomy
Climate change, population growth may lead to open ocean aquaculture
05.10.2017 | Oregon State University
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses