United States Department of Agriculture, Forest Service
Pacific Southwest Research Station
Sierra Nevada Research Center
Effects of Off-Highway Vehicles (OHV) on Vertebrate Communities
The Research:
Direct effects of OHV use include noise, compaction, collision, trampling,
and simple physical presence of plant and wildlife species, and they can
affect a wide array of trophic levels, ranging from primary producers
to top predators. OHV use in California is growing along with the
burgeoning population of the State. Managing this growth in a manner
that is consistent with multiple land management objectives poses a
mounting challenge to land managers and the OHV user community.
Basic information on how various aspects of OHV use (e.g., presence,
sound, physical effects) affect populations and habitat elements of interest
and concern have thus far presented a barrier to informed OHV use
management. This is particularly true in California, where the number of
species of concern in the State is the second highest in the United States,
following Hawaii. OHV use -- if not managed properly -- has the potential
to jeopardize the long-term persistence of some species.
The purpose of this research is to assess the effects of Off Highway
Vehicles (OHV) on forest-associated vertebrate species and the condition
of their habitats. The study will determine how spatio-temporal factors
related to OHV use affect vertebrate species, with particular emphasis on
shifts in species assemblages, impacts to understory-associated species, the
presence of top carnivores (e.g., marten, northern goshawk, and spotted
owl), and the abundance and distribution of their primary prey.
Objectives:
• To determine the effects of summer OHV use on the composition
and structure of vertebrate assemblages, with emphasis on understory
associates, top predators, and their prey
• To determine the differential effects of fragmentation, vehicle presence,
and noise on vertebrate assemblages
• To evaluate the effects of proximity and intensity of use on nest site
selection for understory bird species, movement of small mammal species,
and daily activity patterns of carnivore species
USDA Forest Service
Pacific Southwest Research Station
Sierra Nevada Research Center
Photo: Lori Campbell
Our Mission:
Sierra Nevada Ecosystems are
complex and our knowledge
of them is incomplete.
As a result, the long term
outcome of any given land
and resource management
strategy is uncertain. We
will provide assistance to
land managers and policy
makers by addressing this
management dilemma
through targeted research,
emphasizing an integrated,
ecoregional approach to
examine particular physical,
ecological, and socioeconomic issues, across a
range of appropriate spatial
and temporal scales specific
to each issue.
This unit will represent the
collective research expertise
and interests of scientists
located in Fresno, Davis
and Albany as well as other
scientists within the Pacific
Southwest Research Station.
With a full spectrum of
research, from long-term,
fundamental research
to short-term, tactical
applications, this Center
is intended to support
conservation, restoration,
and sustainable utilization of
the lands within the Sierra
Nevada ecoregion.
Application of Research Results:
The results of the study will be applied to route designation and the management of
OHV use at designated sites. It has already been used to inform the design of wildlife
monitoring at OHV use areas.
Location:
The study area is located in the central Sierra Nevada on three National Forests:
Lake Tahoe Basin Management Unit, Eldorado NF, and Humboldt-Toiyabe NF.
Publications:
Manley, P.N. and L.A. Campbell. In prep. Interim report: implementation of the
Vertebrate Assemblage OHV study.
Manley, P. N., Stumpf, Joshua P., and Davis, Wesley B. 2004. Pilot test of
programmatic approach to monitoring winter conditions and trends of wildlife
populations and habitats in Off-Highway Vehicle use areas. Unpublished report
submitted to U.S. Forest Service, Pacific Southwest Region, 1323 Club Drive,
Vallejo, CA .
Photo: Lori Campbell
www.fs.fed.us/psw/programs/snrc
USDA Forest Service
Pacific Southwest Research Station
Sierra Nevada Research Center
Albany Location:
800 Buchanan Street
Albany, CA 94710
For further information contact:
Pat Manley, Research Wildlife Biologist;
530-759-1719
Mailing Address:
P.O. Box 245
Berkeley, CA 94701
Peter Stine, Program Manager
Jim Sedell, Station Director
Pacific Southwest Research Station
Phone: 510-559-6300
Fax: 510-559-6440
Davis Location:
2121 Second Street
Suite A101
Davis, CA 95616
Phone: 530-759-1700
Fax: 530-747-0241
Fresno Location:
2081 E. Sierra Avenue
Fresno, CA 93710
Phone: 559-323-3200
Fax: 559-297-3355