Impact of Intraguild Predation and Stage Structure
on Simple Communities along a Productivity Gradient

S.D. Mylius, K. Klumpers, A.M. de Roos & L. Persson, 2001.  Am. Nat. 158 (3): 259-276


We analyze the consequences of intraguild predation and stage structure for the possible composition of a three-species community consisting of resource, consumer, and predator. Intraguild predation, a special case of omnivory, induces two major differences with traditional linear food chain models: the potential for the occurrence of two alternative stable equilibria at intermediate levels of resource productivity and the extinction of the consumer at high productivities. At low productivities, the consumer dominates, while at intermediate productivities, the predator and the consumer can coexist. The qualitative behavior of the model is robust against addition of an invulnerable size class for the consumer population and against addition of an initial, nonpredatory stage for the predator population, which means that the addition of stage structure does not change the pattern. Unless the top predator is substantially less efficient on the bottom resource, it tends to drive the intermediate species extinct over a surprisingly large range of productivities, thus making coexistence generally impossible. These theoretical results indicate that the conditions for stable food chains involving intraguild predation cannot involve strong competition for the bottommost resource.

Download file

Please have a look at a short Note about Copyright before downloading.

File type 1 best for 1 compression 2 size
PDF screen reading - 289 K
PostScript .gz printing gzip 162 K
journal-format PDF - - 224 K

1 : Three file formats are available: PDF® (marked up with hyperlinks: better for screen reading), PostScript® (no hyperlinks but with fancier graphs than the PDF file: better for printing) and journal-format PDF (from the journal in which the paper was published; no hyperlinks).

2 : The PostScript file is compressed with gzip (standard for Unix/Linux, but can be extracted with DOS/Windows' (pk)zip/Winzip as well).

If you have problems with these file formats, please have a look at Help with File Formats.

Press the Back button of your browser or click here to return to the publication list.