Predation and its consequences

Abstract

Predation is ubiquitous. All organisms potentially are prey for others at some stage of the life cycle, and many species encounter predation risk throughout their lives. Furthermore, the potential effects of predation are numerous. They include reduction in abundance or even the elimination of a species from a region, indirect effects on habitat use and foraging efficiency, a potential cascade of interactions through the trophic web, and adaptation via natural selection to persistent predation risk. The latter refers to predation past, while the first three items primarily refer to predation present. They will be discussed separately but with an effort to avoid any false sense of their independence. Prerequisite to evaluating each of these categories of predator effects is some consideration of why predation falls more intensely on some individuals or species relative to others. Thus we begin with the two components of what often is called preference or selectivity, choice for some prey over others on the part of the predator, and differences among prey that influence their relative vulnerability.