Research Organization: Hopland Research & Extension Center,
Division of Agriculture & Natural Resources, University of
California
Principal Investigator: Dr. Robert M. Timm, Center Superintendent
Cooperating Researchers: Dr. Vic Claassen, Land Air & Water
Resources, UC Davis
Charles E. Vaughn, Staff Research Associate IV, HREC
Research Assistants: Stephen L. Young, Staff Research Associate
II, HREC
___tba____, Postgraduate Researcher(s) (specialty in plant sciences)
Time Period of Project: June 1, 2002 through March 31, 2006
(46 months)
[Fiscal Years 2001-2002 through 2005-2006 (overlaps 5 fiscal years)]
Funding Requested: $410,087 450,507 (over 5 fiscal years)
Problem Statement
The California Department of Transportation (Caltrans) manages
approximately 15,000 miles of highway and more than 230,000 acres
of right-of-way throughout the state. A major portion of the management
and maintenance effort is associated with vegetation control.
This need is driven by safety concerns, such as ensuring visibility
of traffic and highway structures and minimizing fire potential
by reducing vegetative biomass. Additionally, vegetation control
provides benefits by reducing the presence of noxious weeds and
other pests, and it is a major component of erosion control. The
proper vegetation cover in Caltrans rights-of-way will improve
motorist safety and erosion control, while reducing the need for
mowing and/or herbicide use.
Caltrans District 1 includes a wide range of climates and plant communities found in Del Norte, Humboldt, Lake, and Mendocino Counties. With the completion of an Environmental Impact Report (EIR) in late 1992, a shift in focus from relying solely on chemical vegetation control to establishing native grasses and low-growing non-native fescues has begun to take shape. As part of an integrated roadside vegetation management (IRVM) program, Caltrans has completed revegetation seeding projects on numerous construction sites. The results from these projects have not been monitored extensively to determine whether they were either successes or failures. In addition, the revegetation practices, which resulted in successful establishment, have not been determined for the range of growing conditions within the four-county district.
The goal of this project is to improve the methodology for
successfully establishing native or desirable, low-maintenance
vegetation on sites/soils following road construction or where
elimination of undesirable vegetation has occurred.
Objective I
Enumerate factors that are known to contribute to successful establishment
of desirable vegetation (as defined by Caltrans landscape architects)
on disturbed sites/soils.
Methods:
Conduct literature review of this topic for publications, guidelines,
and bibliographies pertinent to North Coastal California (Caltrans
District 1).
Confer with revegetation, conservation biology, and plant ecology
authorities with experience pertinent to North Coastal California
conditions (e.g., faculty or extension staff within UC, State
Universities, private universities and colleges, state and federal
agencies, private firms)
Conduct site visits to locations of recent Caltrans revegetation
attempts. Analyze such sites through a cursory review in which
planting success is assessed by examining project specifications
for seed species and planting methodology. Utilize standardized
plant monitoring protocols for describing plant composition and
cover. Additionally, take soil samples from selected Caltrans
revegetation sites and nearby reference sites (less disturbed
soils with established vegetation) to compare nutrient and organic
contents, water holding capacity and microbial activity, which
may include mycorrhizae.
Re-visit sites at least annually for duration of project to determine
whether/what type of subsequent plant succession or invasive competition
occurs. Attempt to conclude whether obvious variables provide
predictive information.
Objective II
From sites where vegetation establishment was unsuccessful, determine
the circumstances or variables that appear to lead to unpredictable
results or predictable planting failure. For such locations/circumstances,
hypothesize changed planting and/or management strategies that
would likely lead to successful revegetation. Pilot-test such
treatments at appropriate sites.
Methods:
Analyze field data from sites of revegetation attempts (see Objective
I) using multivariate analyses in order to determine primary and
secondary reasons why efforts failed or succeeded.
For sites where primary and secondary causes of revegetation failure
appear most evident, develop strategies for initiating successful
revegetation, coupled with testable hypotheses related to correcting
causes of revegetation failure.
Pilot-test treatments or combinations of treatments at three to
five selected sites with moderate soil conditions, in order to
refine a wide range of establishment techniques in controlled
settings1 (HREC, state parks, private landowners, etc.) where
more replications and significant differences can be determined.
Treatments may include: seeding density, species composition (based
on appropriate species for the area), timing of seeding, maintenance
for establishment and weed control, and plant growth regulators.
Amendments may be applied to bring soils to modest nutrient and
water holding capacity levels, if needed.
Evaluate success of test treatments at field sites for overall
improved public safety along highways in terms of establishment
success (maintained plant diversity, while decreasing noxious,
invasive species), erosion prevention or control, and fire risk
reduction2 through the available time period of this project.
1 Settings include lab, greenhouse, and field situations.
2 Specific measurements useful in such evaluation may include
percent cover, plant species composition, plant survival through
time (plant growth habit - annual, perennial, biennial), standard
erosion descriptions and measures, cost:benefit, water quality
measures for runoff such as suspended solids or nutrients.
Objective III
Through practical application of information gained in meeting
Objectives I and II, formulate improved strategies/specifications
for revegetation projects on difficult sites, so as to increase
the chances of successful establishment of desirable vegetation
that will successfully compete with other less desirable plant
species in the local environment. Strategies are likely to be
specific to several common problem site situations (e.g., hot
sites, modest soil conditions, right-of-way slopes, and previous
dense infestations of undesirable plants). Report on findings
and developing strategies to Caltrans personnel through seminars
or workshops to be held in both Northern and Southern California.
Share research findings through appropriate scientific (peer-reviewed)
as well as semi-technical publications in appropriate periodicals.
Provide findings to Caltrans in appropriate format for inclusion
in agencyís web sites.
Methods
In consultation with colleagues and cooperators, draft guidelines
for improving success of revegetation projects on various types
of North Coast sites where past success of such efforts has been
low. (These guidelines are likely to be specific to the more common
site characteristics).
Establish a demonstration project site approximately 2 acres in
size to show a vegetative conversion of an area dominated by weeds
or other undesirable plant species.
Provide wording to Caltrans, facilitating the agencyís
incorporation of this new information and improved revegetation
strategies into the District 1 erosion control specifications
for construction projects.
Publish findings by submitting research to appropriate journals
and periodicals
Provide finds to Caltrans in HTML format or other format appropriate
for inclusion in web sites.
Benefits
Short term
Determination and quantitative analysis of whether past seeding
/ planting projects have been successes or failures for Caltrans.
From this information, make necessary changes in current seeding
/ planting methods (i.e. timing, maintenance) to make future construction
revegetation projects more successful and cost effective
Long term
Overall reduction in right-of-way maintenance costs (i.e. mowing,
mulching, and bioherbicides) once native/low-growing vegetation
has been established and niches for invasive, non-native species
have been severely diminished.
Increase biodiversity of environment for wildlife habitat and
lower the spread of invasive species via highway corridors.
Improve public perception, at the risk of lowering aesthetically
appealing ìlawn-scapedî settings.
Implementation
The results of this research will provide Caltrans District 1
information about whether changes are needed in current protocols
for revegetating sites after construction for erosion control
and habitat biodiversity. Findings and recommendations will be
shared with agency personnel through regional workshops or seminars,
as well as through publications in various journals and semi-technical
magazines. Personnel involved with revegetation projects will
be better informed on the most effective procedures for establishing
native vegetation. Moreover, a reduction in both the costs of
Caltrans roadside maintenance and public concern will be realized.
Work Plan
Year 1 - June 2002 (FY2001-2002)
Search literature/internet for information related to establishing
native vegetation.
Review current revegetation practices used by Caltrans including
site preparation and seeding procedures.
Begin locating appropriate rights-of-way and roadside sites for
planting trials.
Year 2 - July 2002 through June 2003 (FY2002-2003)
Inventory and evaluate selected revegetation sites (i.e. species
frequency, canopy cover, species height, and aboveground biomass)
Provide description of apparent erosion that has occurred at each
site sampled.
Perform detailed soil analysis including nutrient content, organic
matter, water holding capacity and microbial populations on sites
and nearby reference sites with established vegetation.
Continue literature/internet search and maintain/establish contacts
with persons having particular expertise concerning revegetation
techniques/practices.
Interim report that summarize findings, conclusions, and recommendations
for Objective I.
Establish plantings and begin testing treatments in controlled
settings (lab, greenhouse, field plots)
Construct 3 field plots using improved site preparation and vegetation
establishment techniques
Year 3 - July 2003 through June 2004 (FY2003-2004)
Monitor existing plantings in controlled settings with more plots
added if needed.
Revegetation strategies and specific development for plant establishment
will be ready for pilot-testing by means of incorporation into
construction projects.
Workshops/seminars for Caltrans personnel will be initiated.
Installation of vegetation conversion demonstration project at
selected location(s).
Year 4 - July 2004 through June 2005 (FY2004-2005)
Perform necessary maintenance on sites during the growing season.
Evaluate sites from previous years and prepare appropriate reports.
Revise revegetation strategies, based on recent results and hypotheses.
Interim report that summarize findings, conclusions, and recommendations
for Objective II.
Continue to report results of work in written, oral, and web-based
formats as appropriate.
Submit manuscripts to appropriate journals, periodicals, and conferences
or symposia.
Provide written suggestions / recommendations to agency, based
on results to date.
Year 5 - July 2005 through March 2006 (FY2005-2006)
Evaluate sites from previous years, and summarize data.
Continue to report results of work in written, oral, and web-based
formats as appropriate. Work with journal editors on revision
of manuscripts, or on final details of accepted papers, for publication.
Attend appropriate conferences and symposia to report on findings.
Provide appropriate forums for agency to receive and disseminate
information within the state.
Prepare, review, and finalize project final report, which will
include suggestions to agency on follow-up or related studies
that would build on information gained in this project.
Research Staff
Robert M. Timm, Ph.D. (Superintendent, UC Hopland Res. & Ext.
Center) will provide overall coordination and project management.
Stephen L. Young, Staff Research Associate II at the Hopland R&E
Center (currently employed under existing Study I funded by Caltrans)
will devote a portion of his time to the new project in its first
12 months, and then will become full-time on this project beginning
in July 2002. Two additional Postgraduate Researchers (or Staff
Research Associate I) with expertise in plant sciences will be
filled; depending on interests and qualifications of applicants,
this position could be combined into a single full-time position.
Our anticipation is that this function would be performed by 1
or 2 graduate students who would be undertaking M.S. thesis projects
at UC Davis or UC Berkeley. Vic Claassen, Ph.D. (Dept. of Land
Air & Water Resources, UCD) will assist in site selection,
field sampling implementation, and data interpretation with particular
emphasis on soil sampling. Charles Vaughn, SRA IV at HREC (M.S.
in soil sciences) will serve as a consultant and resource person
to the project and will conduct selected lab analyses. The individuals
funded by this project will be responsible for field work, including
study plot establishment, monitoring, and data collection and
analysis; and for preparing manuscripts and articles, web-based
information, and oral reports to Caltrans personnel and for submission
to appropriate professional meetings and symposia. Dr. Timm will
provide appropriate oversight for the team and the project during
its duration.
Facilities Available
Laboratory, office, and dormitory facilities are available at
the UC Hopland Res. & Ext. Center (HREC) for project personnel.
Equipment necessary to establish field plots at HREC (tractors,
roto-tillers, seeders, plot fence construction tools), and to
measure plant growth and frequency of occurrence are also available
from the University. University vehicles suitable for highway
use, for travel to study sites, are available at HREC for use
by project staff. Other items provided by the University which
are not charged to the project grant include computers for data
input, storage, and analysis, and for preparing subsequently publications
and audio-visual materials for presentation to various audiences.
Reports
Quarterly progress reports will be submitted as required by Caltrans.
Interim reports generated in Years 2 and 4 will be incorporated
into a comprehensive, detailed final report to be submitted to
Caltrans upon the projectís completion. The final report
will include a 1-2 page Executive Summary as well as a summary
of relevant project data in laymenís terms.
R.M. Timm and S.L Young
UC Hopland Res. & Ext. Center
January 25, 2002 revision
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