Improving Management Strategies to Reduce Damage by Forest and Aquatic Mammals
Nonlethal management approaches depend upon either restricting access
to the resource by the offending animal (e.g., physical or behavioral
barriers, depleting habitat) or reducing the relative desirability of
the protected resource (e.g., repellents, preferred alternative options).
Developing nonlethal means to change damaging behaviors necessitates
a thorough understanding of the underlying mechanisms that govern foraging
behavior. Basic paradigms describing foraging behavior have been developed
for experimental species (e.g., rats) and domestic animals (e.g., sheep).
However, prior to developing management tools for wildlife based on
these paradigms, it is essential to confirm similar behaviors in wildlife
species, and to expand our knowledge in pertinent areas.
Often, tools designed to limit wildlife damage rely on certain expected
chemosensory responses, but the sensory perception of most wildlife
species is virtually unknown. There also is a limited understanding
of other factors affecting the usefulness of management tools, such
as when and where they are applied, why animals select specific foods
or areas to forage, and how animals move and disperse. Effective approaches
require specific changes in behaviors of targeted species, and approaches
developed and marketed to reduce damaging behaviors often fail because
there is a flawed understanding of the biological or behavioral traits
of the targeted species.
Nonlethal physical deterrents are effective if they are constructed
to completely impede access by offending wildlife. However, construction
and maintenance are often cost prohibitive. Less expensive materials
and reduced labor costs would be desirable and need to be identified.
Necessary strength, size, and configuration must be determined. Further,
there is a need to develop an understanding of how these materials affect
animals (e.g., attraction) and plants (e.g. microclimate).
provided a multitude of frightening devices and operating systems
(e.g., acoustics, visuals, detection devices), but little is
known about how wildlife responses will vary depending on an
animal's status (i.e., male vs. female, dominant vs. submissive,
individuals vs. group), delivery intervals used with a device,
and other factors.
At present, most repellents are ineffective
to deter foraging behavior of target species. In fact a preponderance
of these substances contain active ingredients to which the target species
are indifferent or are offered at concentrations below avoidance thresholds.
Under some circumstances, such as when wildlife populations exceed
the capacity of available foraging resources, the only feasible means
to protect forest resources is by suppressing specific wildlife populations
during periods of vulnerability. Therefore, effective lethal tools (i.e.,
baits) for pertinent rodent species need to be developed or identified
that function in the most humane and environmentally safe means possible.