Limits to trophic levels and omnivory
in complex food webs: theory and data.
Feissel, "Effects of enrichment on three-level food chains with omnivory
," American Naturalist, vol.155, no.
Ecological Relationships of Turtles In North Florida Lakes: A Study of Omnivory
and the Structure of a Lake Food Web (doctoral dissertation).
needs a behavioral perspective.
It should be noted, however, that at least some collected species likely do not strictly fit any one category, but rather exhibit some measure of omnivory
. Moreover, because only one collecting method was used, Table 3 should not be considered an exhaustive list of all NFHR fish species.
As a test of this prediction, a survey of estrogen and testosterone concentrations in a wide range of vertebrate species representing carnivory, omnivory
, specialist herbivory, and generalist herbivory should reveal a general pattern of increasing sex steroid concentrations.
The exception to this pattern among minnows was the golden shiner (Notemigonus crysoleucas) which was most abundant in the pond and more lentic slough habitat, where omnivory
is an advantage during summer algal blooms or periods of low secondary production.
The widespread occurrence of intraguild predation and other forms of omnivory
in natural food webs (e.g., Bradley 1983, ter Braak 1986, Menge and Sutherland 1987, Polis 1991, 1994, Diehi 1992, 1993) has led Polis and Strong (1996) to question the validity of the trophic level concept and the generality of trophic cascades.
Increases in numbers of raccoons since the 1940s are attributed to their adaptability and omnivory
At the very least, it is important to investigate whether the dissipation effect would still occur in judgments about a more complex food web, such as one with marked omnivory
(Pimm, 1982) and this is also a goal for future research.
can be a substantial advantage for invasive species; even if the rate of mass increase is modest, the numerous potential food sources should allow young snails to survive for long periods of time, perhaps until a more favorable food resource germinates or otherwise becomes available.