Chapters 1 - U.S. Fish and Wildlife Service

Environmental Consequences
the future through the PUP approval process. Under the IPM Plan, the potential effects to
Refuge resources from the proposed site-, time-, and target-specific use of current and potentially
future pesticides on the Refuge would be evaluated using scientific information and analyses
documented in “Chemical Profiles” of the IPM Plan (Appendix C). These profiles provide
quantitative assessment/screening tools and threshold values to evaluate potential effects to
species groups (e.g., birds, mammals, and fish). A PUP (including appropriate BMPs) is approved
where the Chemical Profiles provide scientific evidence that potential impacts to biological
resources are likely to be only minor, temporary, or localized in nature. Along with the selective
use of pesticides, the IPM Plan proposes other appropriate strategies (i.e., biological, physical,
mechanical, cultural methods) to eradicate, control, or contain pest species in order to achieve
resource management objectives. Based on scientific information and analyses documented in
“Chemical Profiles” (see Appendix C), pesticides allowed for use on the Refuge would be of
relatively low risk to non-target organisms as a result of low toxicity or short-term persistence in
the environment. Therefore, waterbirds would not be substantially affected as a result of the use
of these pesticides.
The proposal to expand control of invasive plant species to beyond the boundaries of the Refuge
through a cooperative effort with the Navy, would be implemented in accordance with the IPM
Plan and would therefore also have the potential for only minor, temporary, or localized impacts to
waterbirds.
Mosquito management proposed under this alternative would also be conducted through an
integrated, phased approach in part to minimize the potential for impacts to wildlife. However, as
described under Alternative A, most chemical control of mosquitoes can result in direct and
indirect adverse effects to one or more non-target species. The altered ecological communities that
may result from these control efforts can impact biological integrity and diversity through
disruptions in food webs and other ecological functions. The effect to some waterbirds could be a
temporary reduction in prey species at or near the control site. Some pesticides also have the
potential to directly impact individual birds, as described in greater detail below.
The OCVCD has requested permission to use three new products to control mosquitoes on the
Refuge: Natular, a larvicide with the active ingredient spinosad; Agnique®, a larvicide and
pupacide made from renewable plant oils; and Anvil in the forms AquaAnvil and Anvil 10+10
ULV, both used in adult mosquito control. The label for Natular identifies this product as toxic to
aquatic organisms. In addition, non-target aquatic invertebrates may be killed in waters where
this pesticide is applied. Agnique is potentially lethal to any aquatic insect that lives on the water
surface or requires contact with the air-water interface. As a result, the use of either of these
products on the Refuge could have indirect, albeit limited, effects on the food base of bird species
that prey on aquatic insects.
In considering direct effects on birds, spinosad, the active ingredient in Natular, shows slight
toxicity to birds, while Agnique, which is considered to be “practically nontoxic,” is not known to
cause direct chronic or acute toxicological effects to birds.
Based on studies of avian acute dietary toxicity and avian acute oral toxicity tests, USEPA (2008b)
classifies phenothrin as practically non-toxic to avian species. Piperonyl butoxide, the other
component of sumithrin, is also considered practically nontoxic to birds on an acute basis (USEPA
2006c). In addition, USEPA has concluded that there is low likelihood of chronic risks to birds
from phenothrin use (USEPA 2008b). The application of AquaAnvil and Anvil 10+10 ULV on the
Refuge could however pose a threat to non-target species, such as birds (due to disturbance
Draft Comprehensive Conservation Plan 5-45