PNAS--Movement ecology 遷移生態學 特輯
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Movement Ecology: Unifying Theory Of How Plants And Animals Move From One Place To Another
ScienceDaily (Dec. 24, 2008) — Movement ecology is a developing academic pursuit, combining expertise in a variety of fields, including biology, ecology, botany, environmental science, physics, mathematics, virology and others. It involves the study of how microorganisms, plants and animals travel from one place to another, sometimes for great distances and in highly surprising ways.
This movement is a crucial component of almost any ecological and evolutionary process, including major problems associated with habitat fragmentation, climate change, biological invasions, and the spread of pests and diseases.
The current edition of the journal, Proceedings of the National Academy of Sciences in the USA (PNAS), contains a 76-page special feature on movement ecology, edited by Prof. Ran Nathan, who heads the Movement Ecology Laboratory in the Department of Evolution, Systematics and Ecology at the Hebrew University's Alexander Silberman Institute of Life Sciences.*
Modern movement research is extensive, estimated to yield nearly 26,000 scientific papers over the last decade. However, this research is characterized by a broad range of specialized scientific approaches, each developed to explore a different type of movement carried out by a specific group of organisms. A cohesive framework that would serve as a unifying theme for developing a general theory of organism movement was lacking.
Movement ecology is a unifying paradigm for studying all types of movement involving all organisms. It places movement itself as the focal theme, and, by providing a unifying framework and common tools, aims at promoting the development of an integrative theory of organism movement for better understanding the causes, mechanisms, patterns and consequences of all movement phenomena.
The conceptual framework of movement ecology asserts that four basic components are needed to describe the mechanisms underlying movement of all kinds: the organism's internal state, which defines its intrinsic motivation to move; the motion and navigation capacities representing, respectively, the organism's basic ability to move and to affect where and when to move; and the broad range of external factors affecting movement. The resulting movement path is the fifth and final component of the proposed framework.
*To promote this subject, Prof. Nathan initiated the establishment of a year-long (2006-2007) international project at the Institute for Advanced Studies of the Hebrew University. The results of that project, as well as contributions of other scientists from around the world, comprise the 13 articles included in the PNAS movement ecology special feature.
New Movement Models Tested In Panama
ScienceDaily (Dec. 17, 2008) — Feeling threatened? Hungry? Looking for a mate? Move! Tracking and remote sensing data are making it easier to locate organisms and find out what they are up to. However, general theories of movement are lacking. In a special feature on Movement Ecology in the journal Proceedings of the National Academy of Sciences, researchers present integrative models for movement of organisms as diverse as gut bacteria, tree seeds, ants, marine larvae and cheetahs.
"Our goal is to develop and test a general theoretical framework for movement that will integrate when, where, how and why organisms move, and will reveal the ecological and evolutionary consequences of movement," says Ran Nathan, research associate at the Smithsonian Tropical Research Institute and associate professor of Evolution, Systematics and Ecology at the Hebrew University of Jerusalem.
To ensure that mathematical models accurately predict real events, several have been developed and tested in complex tropical forest at the Smithsonian's Barro Colorado Island research station in Panama.
One of these is a new model for seed dispersal by wind, which accurately predicts tree seed movement under a wide range of conditions. Because trees can't simply pull up their roots and move in response to climate change or other threats, accurate modeling of tree seed dispersal has major implications for conservation across fragmented ecosystems and for understanding biological diversity.
"We add two entirely new things to this model: First, we consider dispersal in two dimensions, so that we can tell how close seeds fall to siblings who are potential competitors and sources of pests and disease. Previous investigators only considered the distance seeds moved," said S. Joseph Wright, staff scientist at the Smithsonian in Panama. "In the end, we show that the direction of a seed's fall can compensate for large differences in distance moved: the ability of individual seeds and whole groups of trees to move across a landscape is a result of trade-offs with other traits that affect their survival."
The Movement Ecology special feature also includes links to Movebank, an online data repository developed by researchers who would like to contribute and have access to animal tracking data. Movebank is the brainchild of Roland Kays, curator of mammals at the New York Museum in Albany; Martin Wikelski, director of the Max Planck Institute for Ornithology; Tony Fountain, director of the Knowledge and Information Discovery Lab and Sameer Tilak, member of the Cyberinfrastructure Lab for Environmental Observing Systems at the UC San Diego Supercomputer Center.
Wikelski and Kays are also research associates at the Smithsonian Tropical Research Institute, where they set up a multi-user Automated Radio Telemetry System on the large forest dynamics plot on Barro Colorado Island. The system tracks up to 200 animals, seeds or other moving objects around the clock, and makes data available on the Web.
Sensor systems mounted on satellites and on the ground will deliver increasing quantities of information about the changing location of organisms through time. An integrated Movement Ecology paradigm strengthens the ability of researchers to decide which information matters from a biological point of view and to make predictions essential to understanding phenomena from the spread of infectious diseases to habitat use by migratory birds.
Authors of the seed dispersal paper are affiliated with the following institutions: Smithsonian Tropical Research Institute, The Hebrew University of Jerusalem, Ohio State University, UC Berkeley and Duke University.
Journal reference:
- Ref. S. Joseph Wright, Ana Trakhtenbrot, Gil Bohrer, Matteo Detto, Gabriel G. Katul, Nir Horvitz, Helene C. Muller-Landau, Frank A. Jones, Ran Nathan. Understanding strategies for seed dispersal by wind under contrasting atmospheric conditions. PNAS, Online Dec. 1-5, 2008