Vegetation Management and Maintenance Plan - Watsonville ...

In addition, isolated patches of widespread, invasive weeds that are adjacent to non-infested
habitat or mitigation areas are included in this category. These infestations can be removed
with moderate effort, within 1-5 years. These are select occurrences of fennel, wild mustard,
Italian thistle, iceplant, wild radish, poison hemlock, bull thistle, and Harding/canary grass.
Management Goal: Remove all H.1 identified occurrences before they spread; repeat
treatments during Years 1-5 to reach management goal thresholds as listed for each species in
Table 4.
H.2 – Contain Existing Infestations in Select Areas: These areas support widespread
invasive weed species that are difficult to eradicate. Identified treatment areas are somewhat
isolated with limited ability to spread. The management strategy is to prevent these
occurrences from spreading into adjacent un-infested areas. Treatment actions are to control
the perimeter of the infestation (to limit an increase in patch size) depending upon resource
availability.
Management Goal: Keep H.2 designated occurrences from spreading; implement measures to
contain population to existing areas by periodically removing invasive weeds within a fivefoot
wide buffer area.
H.3 – Encourage Spread of Native Species in Select Areas: Encourage the spread of
vigorous native species by clearing successive bands of non-natives from the edges of the
native stands and allowing native plant growth to occur (Bradley Method). Identified
treatment areas occur adjacent to vigorous rose, coyote brush, and berry thickets.
Management Goal: Within H.3 designated areas encourage spread of native thickets by 50%
in five years.
H.4 – Implement Pilot Projects for Removal /Control of Aggressive Invasive Weeds in
Select Areas: Implement pilot weed eradication/control projects to control aggressive weed
species; pilot projects to include solarization, flaming, mowing/weed-whipping,
grazing/browsing, and herbicide application; most actions to be combined with revegetation.
Pilot treatments are most suitable for occurrences of perennial/biennial invasive weeds that
are widespread and where considerable effort will be required to control/reduce/remove their
infestations, such as Harding grass/canary grass, poison hemlock, and Kikuyu grass.
Management Goal: Within H.4 designated areas implement at least one project per year.
H.5 – Facilitate Volunteer Buffer Plantings in Select Areas: Develop volunteer
revegetation projects to install native buffer plantings to minimize weeds, reduce fire hazards
and facilitate slough stewardship. Revegetation projects could include weed removal,
installation of native low-growing shrubs, and temporary irrigation and maintenance.
Appendix C outlines various volunteer projects.
Management Goal: Within H.5 designated areas implement approximately 400 linear feet of
plantings per year.
H.6 – Maintain Mitigation Plantings: Weed, repair, mulch, and irrigate mitigation
plantings; monitor plant survival and report to regulatory agencies as needed. Areas subject to
maintenance are plantings along upper Struve Slough, Lower Struve Slough, Upper
Watsonville Slough and Middle Watsonville Slough (see Chapter 4.0).
Management Goal: Meet permit conditions each year.
H.7 – Modify Existing Mowing Program: Modify timing, intensity and level of mowing
along trail edges. Modified program will reduce infestations of bristly ox-tongue and Harding
grass, and other invasive weeds over time.
Vegetation Management and Maintenance Manual
Draft 30 July 27, 2007