Chapters 1 - U.S. Fish and Wildlife Service

Management Alternatives
Mechanical methods used to remove invasive plants can include digging by hand, a nylon
filament trimmer (weed “whacker”), chain saw, uprooting the plant with a jack or hand pulling,
among other mechanical methods. The areas where weed removal occurs are generally seeded
or planted with native plant species.
Other management activities include protecting and maintaining existing native upland plant
restoration areas near Hog Island, Kitts Highway, Bolsa Avenue, the eastern edge of the 7 th
Street Pond, and to the north of Case Street Pond; supporting the Navy’s efforts to conduct
eelgrass surveys in Anaheim Bay; and cooperating in assessing the performance of the
Refuge’s tidal mitigation areas using the California Rapid Assessment Method. Also
implemented when funding can be secured is the maintenance, and where necessary
replacement, of existing culverts to enhance or restore tidal flow within the main marsh and
adjacent restored wetlands.
Night mammal surveys are conducted on the Refuge and the adjacent NWS in partnership
with the NWSSB. These surveys are conducted to assess the population of potential
mammalian predators that could adversely affect listed species. Volunteers also conduct
monthly high tide and low tide bird counts; the National Audubon Society conducts its annual
Christmas bird count; and a variety of research projects (e.g., round stingray surveys,
Trematode surveys, ghost shrimp study, invasive snail [Littorina littorea] surveys) are
conducted on the Refuge that provide relevant information about Refuge resources or data
that can benefit Refuge management. These scientific investigations require a Special Use
Permit from the Refuge Manager.
Predator Management. Monitoring for the presence of mammalian and avian predators that
could pose a threat to the California least tern nesting colony and/or the light-footed clapper
rail population on the Refuge is an important component of the Refuge’s wildlife and habitat
management program. Predator management continues to be implemented in accordance with
the Endangered Species Management and Protection Plan (USFWS and Navy 1991), which
addresses predator management throughout NWSSB, including the Refuge.
The Endangered Species Management and Protection Plan (USFWS and Navy 1991) is a
comprehensive plan that includes species population monitoring, endangered species studies,
endangered species protection, predator control, habitat management, habitat restoration and
enhancement, and monitoring and researching environmental quality. An objective of the plan
is to establish a more naturally balanced ecosystem within the Refuge and NWSSB that is
supportive of endangered species and other native wildlife. The principal means for providing
endangered species protection on the Refuge involves habitat modification and population
management. All methods used for controlling predators on the Refuge are implemented in
conformance with government regulations and have been approved subject to Service and U.S.
Department of Agriculture, Animal Damage Control guidelines and requirements.
Predator management on the Refuge includes indirect and direct control of predators.
Indirect control includes maintenance of barriers and fencing around NASA Island and the
“Eyes on the Colony” volunteer program. Direct control includes live capture and release offsite,
live capture and euthanization, shooting, and toxicant application.
In general, predator species are controlled based on location, seasonality, and number of
predator signs or sightings. The following factors are considered before implementing control
of a particular predator: the nature and degree of threat to endangered species; the estimated
population of the predator species; location of the predator sightings and signs to endangered
Draft Comprehensive Conservation Plan/Environmental Assessment 3-17