Chapters 1 - U.S. Fish and Wildlife Service

Environmental Consequences
Alternative B, and as previously described, these activities would not result in any significant
impacts to terrestrial invertebrates, amphibians, or reptiles.
The proposed restoration of the majority of the Refuge’s remaining disturbed upland habitat to
tidally influenced habitat could adversely affect some individuals of native terrestrial invertebrates
and reptiles, but such losses would be low and therefore not considered significant. In areas
around the 7 th Street Pond, where tiger beetles may be present, a more detailed survey of potential
tiger beetle habitat would be conducted prior to completing specific restoration plans for adjacent
upland areas. If important tiger beetle habitat is identified, preservation of that habitat, as
appropriate, would be incorporated into the future restoration design for that area.
Pest Management
Implementation of the draft IPM Plan for the Refuge (Appendix C), as described above, would
ensure that no adverse effects to the Refuge’s terrestrial invertebrates, amphibians, or reptiles
would occur as a result of the use of pesticides. Studies indicate sensitivity of some species in the
order Coleoptera to methoprene (Marten et al. 1993). This is of concern on the Refuge because at
least two of the areas currently being treated for mosquitoes are believed to support one or more
species of tiger beetles (in the order Coleoptera). A search of the existing literature did not find
any studies that evaluated the effect of methoprene on tiger beetles; therefore, the risk of using
this product in areas where these organisms occur is unknown. To avoid any adverse effects to
tiger beetles, a stipulation in the Compatibility Determination for mosquito use (Appendix A-3) is
to prohibit the use of Altodsid in areas of the Refuge that are known or expected to support high
numbers of tiger beetles.
Of the mosquito control products proposed for use on the Refuge under this alternative, Natular,
AquaAnvil, and Anvil 10 + 10 ULV all have the potential to adversely affect terrestrial
invertebrates. Spinosad, the active ingredient in Natular, is a broad-spectrum pesticide but is only
active if ingested or contacted while in liquid form. The USEPA categorizes spinosad as highly
toxic to bees, with topical acute activity of less than 1 microgram per bee. It also impacts species in
the orders Lepidoptera and Coleoptera (Thompson et al. no date). Some spinosad products are
used to kill fire ants, a soil dwelling species. It is not known if these or other spinosad-based
products could have adverse effects on native ants or other soil fauna. As a result, native
pollinators and other non-target species could be at risk should this product be used on the Refuge.
According to the USEPA (2008b), phenothrin is highly toxic on an acute contact basis to non-target
terrestrial insects, particularly to honeybees. Honeybees could also face indirect dietary risks
from phenothrin toxicity. Piperonyl butoxide, which is also present in the adulticides proposed for
use of the Refuge, increases the toxicity of phenothrin to non-target insects (USEPA 2006c).
Because the control of adult mosquitoes would likely be required between the months of April and
October, the time of year when non-target insects are most active, the potential for non-target
insect to be exposed to sumithrin during its application would be considered high. Therefore, the
application of sumithrin may pose significant acute risks to non-target insects.
A number of studies have been conducted to evaluate the effects of ultra-low volume pesticide
applications on non-target insects of various kinds. Boyce et al. (2007) in studying the effects of the
aerial application of a pyrethrin insecticide synergized with piperonyl butoxide found no adverse
effects to larger arthropods such as dragonflies, butterflies, spiders, and honeybees, but did
identify a measurable impact on a wide range of small-bodied organisms. It is noted in the study
that “although the diversity of affected species was high, the overall numbers of any given taxon
were quite low” (Boyce et al. 2007). The authors conclude that “additional, carefully controlled
studies [of vector control activities] are needed to more fully understand the short- and long-term
Draft Comprehensive Conservation Plan 5-49