Title |
Permanence does not predict the commonly measured food web structural attributes.
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Published in |
The American Naturalist, February 2008
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DOI | 10.1086/524953 |
Pubmed ID | |
Authors |
Nadiah P Kristensen |
Abstract |
Food web assembly algorithms show great promise for investigating issues involving the dynamics of whole webs, such as succession, rehabilitation, and invasibility. Permanence, which requires that all species densities remain positive and finite, has been suggested as a good stability constraint. This study tests the validity of the permanence constraint by comparing real webs and model webs from the literature to the predictions of three assembly algorithms: one constrained by permanence and feasibility, one constrained by feasibility alone, and one with no dynamical constraint. It is found that the addition of the permanence constraint does not improve the predictive ability of the algorithm. Its main effect is to increase the efficiency of species selected for the web. Dynamically constrained webs have lower connectance and indistinct trophic levels compared to real webs and webs from other models, which is a consequence of omitting species' physiology. Although webs are less likely to be permanent if they have high omnivory and cycling, the web-building process circumvents this constraint. The challenges of testing and justifying system-level hypotheses, including isolating and detecting their effects, are discussed. |
Mendeley readers
Geographical breakdown
Country | Count | As % |
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United States | 4 | 7% |
France | 2 | 4% |
United Kingdom | 2 | 4% |
Mexico | 1 | 2% |
Saudi Arabia | 1 | 2% |
Japan | 1 | 2% |
Namibia | 1 | 2% |
Unknown | 42 | 78% |
Demographic breakdown
Readers by professional status | Count | As % |
---|---|---|
Student > Ph. D. Student | 11 | 20% |
Researcher | 9 | 17% |
Professor | 7 | 13% |
Student > Doctoral Student | 4 | 7% |
Professor > Associate Professor | 4 | 7% |
Other | 11 | 20% |
Unknown | 8 | 15% |
Readers by discipline | Count | As % |
---|---|---|
Agricultural and Biological Sciences | 25 | 46% |
Environmental Science | 10 | 19% |
Mathematics | 3 | 6% |
Psychology | 1 | 2% |
Earth and Planetary Sciences | 1 | 2% |
Other | 0 | 0% |
Unknown | 14 | 26% |