A foodweb is a depiction of species and organisms in a ecosystem of what they comsume and the different type of thing each comsume.
In complex networks of interacting species, numbers of indirect interactions, that is, interactions that require paths of length more than one, goes up exponentially with species diversity. Of course direct interactions potentially increase faster and faster with more species too. Whereas direct interactions are readily understood, indirect interactions can lead to counterintuitive situations that have been called, for example, "apparent competition". When a single predator has two prey species, if a removal experiment is performed on one of the prey, the predator must increase its predation on the other species. A naive community ecologist might interpret the response as competition when it isn't competition at all! Other such indirect interactions involve more than just two links. One I find most interesting is in the bottom center, where two consumers are not competing or interacting directly in any way, but because their prey are competing at the next trophic level down, a positive apparent mutualism emerges between the two consumers that has been called facilitation or indirect mutualism.
Quick Reply
