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Axel Rossberg | 6 Jul 10:05

New food-web model

Dear Colleagues,

I am a bit worried that I was too sharp in the description of the
mailing list about the "signal-to-noise ratio".  It was not meant to
discourage your contributions.  

On the contrary, I really think that progress in our field is at least
partially limited by an imperfect flow of information and the
resulting differences in perspectives.  This is a pity, because
food-webs science could contribute a lot more to urgent questions
related to biodiversity, invasive species, and fisheries, and also
fundamental problems of macroecology, than it currently does.  The
field has a lot more to offer, and is certainly large enough to
provide a comfortable niche for all of us.

Please tell us about your latest results!

***

Hoping that you do not experience this contribution as "noise", I
would like to bring your attention to a manuscript of us on

      "The top-down mechanism for body mass -- abundance scaling"

(http://axel.rossberg.net/paper/Rossberg2007b.pdf), recently accepted
for Ecology.

The Appendix of the paper describes a new evolutionary food-web model
which is probably the most complex, but perhaps also the most
realistic available so far.  Copy-right issues pending, the code of
(Continue reading)

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Per Arne Rikvold | 22 Jul 19:00
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My recent publications

Dear Foodwebbers,

Here are the URLs of my two most recent papers on evolution of food-web
structure for an individual-based evolutionary predator-prey model:

P.A. Rikvold and V. Sevim, 
``Individual-based Predator-prey Model for Biological Coevolution:
Fluctuations, Stability, and Community Structure."
Phys. Rev. E 75, 051920 (2007) (17 pages).
http://link.aps.org/abstract/PRE/v75/e051920
Free preprint: http://arXiv.org/abs/q-bio.PE/0611023

P.A. Rikvold,
``Self-optimization, Community Stability, and Fluctuations
in Two Individual-based Models of Biological Coevolution."
J. Math. Biol., published online:  
http://dx.doi.org/10.1007/s00285-007-0101-y
Free preprint: http://arXiv.org/abs/q-bio.PE/0508025
(The preprint version contains a discussion of the difference between 
the effects of an external resource and a carrying capacity, which the
editor of JMB insisted I must remove from the published version. 
Especially for people with a physics background, the difference should
be quite clear: the external resource has an effect similar to the
magnetic field in an Ising model, while the carrying capacity is the
inverse of the term in the Ginzburg-Landau Hamiltonian that keeps the
order parameter from diverging to infinity in the ordered phase.)

Some earlier papers on the same evolution models, but with less emphasis
on the food-web structure and more on the long-time dynamics, are:
(Continue reading)

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Lyne Morissette | 29 Jul 14:12
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Job opportunity: data technician - Arizona State University

Research Technician in Marine Food Web Modeling

Arizona StateUniversity

 

Applications are invited for a technician position to contribute to an international project on interactions between whales and fisheries.  The position is available from September 1, 2007.  The technician will develop and manage a database for sources of information needed for ecosystem modeling (Ecopath with Ecosim).  This includes compilation of marine fisheries and biological data needed for food web modeling purposes from available databases, literature and other sources, and preparation of data for incorporation in mass-balance food web model.  Incumbents must have a thorough understanding of the theory behind tasks being performed, and will be required to work independently but remain in close communication with team members. The data technician will also assist with preparation of documents and materials needed for workshops held for the purpose of disseminating results from the project.  The person will be based at ArizonaStateUniversity in Tempe, and may be required to travel to Canada for project purposes.  

 

Examples of Duties:

  • Performs scientific data collection, analyses and syntheses involving routine procedures characterized by availability to work independently and reliably on assigned tasks.

  • Maintains detailed records of studies conducted; organizes data; prepares data for Ecopath input and records modelling results.

  • Compiles data and generates statistical data for analytical purposes using Access; makes preliminary Ecopath analyses and assists researchers in interpreting the data.

  • Conducts literature searches to find diet, production, consumption or biomass information about the trophic groups of the food web models.

  • Writes summaries of projects, documenting location, findings and procedures used and assists in writing reports by conducting literature searches and background research; prepares bibliographies as required.

  • Interacts regularly with the project postdoc, who is the lead ecosystem modeler.

 

Knowledge, Skills and Abilities:

  • Knowledge of ecosystem or food web modelling techniques and principles as well as experience working with Ecopath with Ecosim.

  • Experience in mining and compilation of data needed for foodweb modelling (fisheries time series, biomass, diets etc of functional groups in marine ecosystems), including database skills (Access).

  • Working knowledge of fisheries management techniques, including stock assessment methods, total allowable catches, catches per unit of efforts, etc.

  • Experience in working independently in association with remote collaborators.

  • Skill in both verbal and written communication.

  • Skill in analyzing and evaluating data.

 

Minimum Qualifications:

Masters degree in marine biology, fisheries science or related discipline; OR, Four years research experience appropriate to the area of assignment; OR, Any equivalent combination of experience and/or education from which comparable knowledge, skills and abilities have been achieved.

 

To apply:

Send CV, statement of relevant research experience and interests, and contact information for 3 references to leah.gerber-tTJs1oqo2yY@public.gmane.org. Closing date: 8/15/2007, or until a successful candidate is identified. Arizona State University is an Equal Opportunity/Affirmative Action Employer

 

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