Geoscience Reference
In-Depth Information
Chapter 5
Investigating Food Habits of
Terrestrial Vertebrates
JOHN A. LITVAITIS
Why study food habits? Probably one of the most fundamental questions that
ecologists attempt to answer is, “What resources does a particular species
require to exist?” Indeed, the first principle among wildlife ecologists is to have
a thorough understanding of the food, cover, and water requirements of an ani-
mal before initiating any effort to alter the factors that may be limiting it. Infor-
mation on food habits is therefore an important introduction to the natural his-
tory of any species. This has been a justification for many studies of food habits
of vertebrates (Martin et al. 1961) and is still a valid reason to investigate the
diet of any species when little information is available (Salas and Fuller 1996).
Food habits have been investigated for a variety of other reasons. Such infor-
mation is essential in understanding the potential competitive interactions
among sympatric species ( Jaksic et al. 1992; Wiens 1993) or in determining
how the foraging patterns of individuals affect community composition. For
example, how does grazing by wildebeests (
Connochaetes taurinus
) affect the
diversity of grasses and forbs? Does predation by lions (
Panthera leo
) limit that
same wildebeest population? A simple list of foods used by wildebeests or lions
will not answer these questions. However, determining the biomass consumed
and abundance of alternative forage or prey is an important first step in under-
standing how these two species influence community composition.
In human-dominated landscapes, information on the food habits of com-
mon terrestrial vertebrates has been useful in understanding the “economic
food niche” of many species. Losses of livestock, agricultural crops, or game
populations are serious economic concerns. Limiting these losses is a major
charge of government wildlife management agencies. Historically, efforts to
control depredating wildlife have included indiscriminate attempts to reduce
populations of the offending species. Well-known examples of such an
