Draft Programmatic Environmental Impact Statement/Environmental Impact Report
San Francisco Estuary Invasive Spartina Project: Spartina Control Program
April 2003

Table 3.3-1:  Summary of Potential Biological Resources Effects

 

Impact

Manual Removal
(Hand pulling and manual
excavation)

Mechanical
Removal
(Excavation, dredging, and shredding)

Pruning, Hand-mowing, and Smothering

Flooding
(Diking, drowning, and salinity
variation)

Burning

Herbicide
Application

Beneficial Effects

BIO-1.1: Effects on
tidal marsh plant
communities
affected by salt-meadow cordgrass and English cordgrass.

All Alternatives:  Local, short-term minor adverse
effects would be possible because of incidental trampling by crews.

 

All Alternatives: Minor to moderate adverse impacts could occur
because of damage from vehicles on mats, trampling.

 

All Alternatives: Minor adverse
effects may occur if geotextile fabric is displaced and damages non-target vegetation. Repeat mowing
or smothering treatments would result in local but persistent trampling damage.

 

All Alternatives: Not applicable: method not feasible for existing infestation, generally
infeasible for
 potential small infestations in the high salt marsh zone. 

 

All Alternatives: Not applicable: method not feasible for existing infestation, probably
generally infeasible for potential small infestations of this species; no adverse impact.

 

Alternatives 1, 3:  Potential local, persistent (to 2-3 year), adverse impact due to spray drift effect on non-target emergent marsh vegetation.

Alternative 2: No impact.

Alternatives 1 & 2:
Eradication of the existing small
regional infestation is likely, resulting in early arrest of spread to regional tidal marshes.  Significant long-term benefit.

Alternative 3:  Short-term benefits of continued uncoordinated contyrol efforts; no long-term benefits.

BIO-1.2: Effects on tidal marsh plant communities affected by Atlantic smooth cordgrass and its hybrids.

Alternative 1: Minor to moderate short-term local adverse impacts due to incidental trampling by crews.

Alternative 2:
Proportionally more use of this method than in Alternative 1, greater impact, but not significant.

Alternative 3:
Less regional use and impact than Alternatives 1 & 2.

 

Alternative 1:
Minor to moderate
adverse impacts if limited to isolated mudflat colonies: potentially
significant adverse impacts if applied to extensive colonies within existing tidal marsh.

Alternative 2:
Proportionally more regional use of this method than Alternative 1, greater impact, potentially significant.

Alternative 3:
Less impact than
Alternatives 1& 2.

 

Alternative 1:
Minor adverse
effects may occur
if geotextile fabric is displaced and damages non-target vegetation.  Repeat mowing
or smothering treatments would result in local but persistent trampling damage.

Alternative 2:
Proportionally more use of this method than Alternative 1, greater impact, but not significant.

Alternative 3:
Less regional use of and impact of this method than Alternatives 1 & 2.

 

Alternative 1:
Potentially
significant short-term (1-3 year) large-scale impacts due to non-selective
eradication caused by impoundment of existing salt marsh vegetation.

Alternative 2:
Proportionally more use of this method than Alternative 1, greater impact.

Alternative 3:
Low or no impact
if used.

 

Alternatives 1-3A: Local, short-term adverse impacts
to tidal marsh vegetation marginal to burned areas; low potential for inadvertent spread of fire to in tidal marsh vegetation adjacent to smooth cordgrass. Limited potential for use.

Alternative 3:
No impact.

Alternatives 1, 3A: Local, moderately persistent adverse impacts of herbicide spray drift on tidal marsh vegetation adjacent to treated areas could occur from manual and normal helicopter application. Minimal non-target impacts to vegetation could occur from wick/
brush applications.  Significant adverse impacts could occur from worst-case helicopter spray drift.

Alternative 2,

Alternatives 1:
Long-term benefit to regional tidal marsh communities due to arrest of invasion.

Alternatives 2-3: Temporary local benefits from
individual eradication
projects; no long-term or significant benefits.

Alternative 3:  Short-term benefits of continued uncoordinated contyrol efforts; no long-term benefits.

BIO-1.3: Effects on tidal marsh plant communities affected by Chilean cordgrass.

Alternative 1:
Minor to moderate
adverse impacts due to incidental trampling by crews.

Alternative 2:
Proportionally greater use and impact of this method than
Alternative 1, but not significant.

Alternative 3A:
Less trampling impact than
Alternatives 1 & 2.

 

All Alternatives: Unlikely methods for known infestations of this high salt marsh species.  Local, short-term minor to moderate adverse impacts could occur
because of damage from vehicles on mats, trampling.

 

Alternatives 1, 3A: Local, short-term minor adverse
effects may occur
if geotextile fabric is displaced and damages non-target vegetation.  Repeat mowing
or smothering treatments would result in local but persistent trampling damage.

Alternative 2:
Greater impact of this method than
Alternative 1, but not significant.

 

All Alternatives : Not applicable: method not feasible for existing
infestation,
generally infeasible for potential small infestations of this species in the high salt marsh zone. 

 

All Alternatives: Minor to moderate local and short-term adverse impacts due to marginal impacts to non-target salt marsh vegetation.  Limited applicability of this method for known infestations.

 

Alternative 1:
Minor to moderate short-term adverse
impact due to spray drift from manual applications.
Helicopter spray probably infeasible for known
infestations of
this species.

Alternative 2:
No impact.

Alternative 1: Probably fastest regional eradication, lowest risk of regional spread. Greatest significant long-term benefit.

Alternatives 2, 3 Possibly slower but feasible regional eradication and arrested spread. Significant long-term benefit.

 

BIO-1.4: Effects
on submerged aquatic plant
communities.

 

Alternative 1:
No adverse impact.

Alternatives 2& 3: No impact.

.

Alternative 1:
No adverse impact.

Alternatives 2 & 3: No impact.

 

All Alternatives: minimal adverse impact. Leaf litter from mowing could raft on high tides and deposit in pans, causing one
growing season of local wigeongrass dieback. Moderate to minor impact.

Alternative 2: No impact.

All Alternatives:
No adverse impact.

 

All Alternatives:
No adverse impact.

 

All Alternatives:
No adverse impact.

 

Alternatives 1-2: Short-term
increases in habitat due to flooding (impoundment) methods in some cases, potentially significant benefits over life of regional program due to prevention of
invasion by smooth cordgrass.

Alternative 3:
No long-term benefits.

BIO-2: Effects on
special-status plants in tidal marshes.

Alternative 1: Local, short-term potentially significant impacts to soft-bird's beak due to incidental trampling or disturbance, only with removal of known saltmeadow and Chilean cordgrass infestations.

Alternative 2: Greater impact than Alternative 1.

Alternative 3: Less impact than
Alternative 1 but still significant.

 

Alternative 1: Local, short-term potentially saignificant impacts to soft-bird's beak due to incidental trampling or disturbance, only with removal of known saltmeadow and Chilean cordgrass infestations.

Alternative 2: Greater impact than Alternative 1.

Alternative 3: Less impact than
Alternative 1.

 

Alternative 1: Local, short-term minor adverse effects may occur if
geotextile fabric (smothering) is displaced and damages soft bird's-beak
populations.
Repeat mowing treatments would result in local but persistent trampling damage; only with removal of known saltmeadow and Chilean cordgrass infestations.

Alternative 2: Greater impact than Alternative 1.

Alternative 3: Less impact than
Alternative 1 but still significant.

 

All Alternatives: This method is unlikely to be
applied to any habitats supporting special-status plants (smooth cordgrass only);
no impact.

 

 

 

All Alternatives: This method is unlikely to be
applied to any habitats supporting special-status plants (smooth cordgrass only);
no impact.

.

Alternative 1:
Potentially
significant adverse impacts to soft bird's-beak, only with removal of known saltmeadow and Chilean cordgrass infestations. (less than
significant with mitigation).

Alternative 2:
No impact.

Alternative 3:
Less impact than Alternative 1.

 

Alternative 1:
Pacific cordgrass likely to avoid
regional extinction; California sea-blite recovery feasibility increased; threats reduced for other rare species; all significant long-term benefits.

Alternatives 2, 3: short- to moderate-term benefits, probably no long-term benefits.

 

BIO-3: Effects on shorebirds and waterfowl.

Alternative 1:
Short-term, local potentially significant disturbance of shorebirds and waterfowl in vicinity of access and treatment areas (slough and mudflat).

Alternative 2: Greater impact than Alternative 1.

Alternative 3.
Less impact than
Alternative 1.

 

Alternative 1:
Short-term, local potentially significant disturbance of shorebirds and waterfowl in vicinity of access and treatment areas (slough and mudflat).  Moderate adverse impact.

Alternative 2: Greater impact than Alternative 1.

Alternative 3:
Less impact than
Alternative 1.

 

Alternative 1:
Short-term, local disturbance of shorebirds and waterfowl in vicinity of access and treatment areas (slough and mudflat).  Moderate adverse impact.

Alternative 2: Greater impact than Alternative 1.

Alternative 3:
Less impact than
Alternative 1.

 

Alternative 1:
If impoundment
requires construction of berms or
inflatable dams, short-term, local disturbance waterfowl of shorebirds

Alternative 2: Greater impact than Alternative 1.

Alternative 3: Low or no adverse impact if used.

 

Alternative 1:
Short-term, local disturbance of shorebirds and waterfowl in vicinity of access and treatment areas (slough and mudflat).  Moderate adverse impact.

Alternative 2: Greater impact than Alternative 1.

Alternative 3:
Less impact than
Alternative 1.

 

Alternative 1:
Short-term, local disturbance of shorebirds and waterfowl in vicinity of access and treatment areas (slough and mudflat).  Moderate adverse impact.  Potentially
significant impacts if helicopters are used for repeat treatment of large mudflat colonies.

Alternative 2:
No impact.

Alternative 3:
Less impact than
Alternative 1.

 

Alternative 1:
Long-term region-wide increase or
stabilization and protection of
primary foraging and roosting
habitats in tidal mudflats at key stopover in Pacific flyway. Highly
significant benefit.

Alternatives 2, 3: Relatively short-term (ca. 10 yr) increase of primary foraging and
roosting habitat. Moderate benefit.

 

BIO-4.1: Effects on the salt marsh harvest mouse and tidal marsh shrew
species.

Alternative 1: Eradication of non-native cordgrass in high marsh may have significant short-term adverse impacts in few locations, but usually minor or none.  Local, short-term minor to moderate adverse impacts due to incidental trampling or disturbance.

Alternative 2:
Greater impact than Alternative 1.

Alternative 3:
Less impact than Alternative 1.

 

Alternative 1: Eradication of non-native cordgrass in high marsh may have significant short-term adverse impacts in few locations, but usually minor or none.  Local, short-term minor to moderate adverse impacts due to incidental trampling or disturbance.

Alternative 2:
Greater impact than Alternative 1.

Alternative 3:
Less impact than Alternative 1.

 

Alternative 1: Eradication of non-native cordgrass in high marsh may have significant short-term adverse impacts in few locations, but usually minor or none.  Local, short-term minor to moderate adverse impacts due to incidental trampling or disturbance.

Alternative 2:
Greater impact than Alternative 1.

Alternative 3:
Less impact than Alternative 1.

 

Alternative 1: Method probably not applicable to high marsh habitat of small tidal marsh mammal species; minor impacts of feasible applications.

Alternative 2:
Proportionally greater, but not significant impacts than Alternative 1.

Alternative 3: Method probably infeasible without regionally coordinated mitigation for scale of wildlife impacts; low or no adverse impact if used.

 

Alternative 1: Eradication of non-native cordgrass in high marsh may have significant short-term adverse impacts in few locations, but usually minor or none.  Local, short-term minor to moderate adverse impacts due to incidental trampling or disturbance.

Alternative 2:
Greater impact than Alternative 1.

Alternative 3:
Less impact than Alternative 1.

 

Alternative 1: Eradication of non-native cordgrass in high marsh may have significant short-term adverse impacts in few locations, but usually minor or none.  Local, short-term minor to moderate adverse impacts due to incidental trampling or disturbance.

Alternative 2:
No impact.

Alternative 3:
Less impact than Alternative 1.

 

Alternative 1:
Probable long-term, widespread cumulative benefit due to arrest of invasions by non-native cordgrass, protection of habitat.  Significant long-term benefit.

Alternatives 2, 3: Temporary local benefits from individual eradication projects, not long-term or significant (invasion likely to overtake eradication).

 

BIO-4.2: Effects on resident harbor seal colonies of San Francisco Bay.

Alternative 1:
Short-term, local disturbance of harbor seals in vicinity of a few access and
treatment areas. Potentially significant adverse impacts at a few potential project sites, minor or no impacts at most project sites.

Alternative 2:
Greater impact than Alternative 1.

Alternative 3:
Less impact than Alternative 1,
potentially significant.

 

Alternative 1:
Short-term, local disturbance of harbor seals in vicinity of a few access and
treatment areas. Potentially
significant adverse impacts at a few potential project sites, minor or no impacts at most project sites.

Alternative 2:
Greater impact than Alternative 1.

Alternative 3:
Less impact than Alternative 1,
potentially significant.

 

Alternative 1:
Short-term, local disturbance of harbor seals in vicinity of a few access and
treatment areas. Potentially
significant adverse impacts at a few potential project sites, minor or no impacts at most project sites.

Alternative 2:
Greater impact than Alternative 1.

Alternative 3:
Less impact than Alternative 1,
potentially significant.

.

Alternative 1:
Short-term, local disturbance of harbor seals in vicinity of a few access and
treatment areas. Potentially
significant adverse impact.  Minor or no impacts at most project sites.

Alternative 2:
Greater impact than Alternative 1.

Alternative 3:
If used, impacts may be significant at a few potential project sites, but minor or no impacts at most sites.

 

Alternative 1:
Short-term, local disturbance of harbor seals in vicinity of a few access and
treatment areas. Potentially
significant adverse impacts at a few potential project sites, minor or no impacts at most project sites.

Alternative 2:
Greater impact than Alternative 1.

Alternative 3:
Less impact than Alternative 1,
potentially significant.

 

Alternative 1:
Short-term, local disturbance of harbor seals in vicinity of a few access and
treatment areas. Potentially
significant adverse impacts at a few potential project sites, minor or no impacts at most project sites.

Alternative 2:
No impact.

Alternative 3:
Less impact than Alternative 1,
potentially significant.

 

Alternative 1: Long-term stabilization of existing haul-out habitats by preventing isolation from encroaching smooth cordgrass.  Significant benefit, especially for Mowry Slough and other south San Francisco Bay colonies.

 Alternatives 2 & 3:
Some short-term benefits, no long-term benefits likely.

 

BIO-4.3: Effects on the southern sea otter.

All alternatives: Negligible or no impact.

All alternatives: Negligible or no impact.

All alternatives: Negligible or no impact.

All alternatives: Negligible or no impact.

All alternatives: Negligible or no impact.

All alternatives: Negligible or no impact.

Long-term
reduction of risk that important habitat in Elkhorn Slough will be
invaded by
pioneers of smooth cordgrass from San Francisco Bay.

BIO-5.1: Effects on
California
clapper rail.

All Alternatives.  Potentially
significant disturbance of clapper rail foraging, mating, nesting, due to treatment activity, resulting habitat destruction, and crew access to rail habitats. Local loss of breeding; risk of mortality. Order of severity:
2 (greatest), 1, 3.

.

All Alternatives.  Potentially
significant disturbance of clapper rail foraging, mating, nesting, due to treatment activity, resulting habitat destruction, and crew access to rail habitats. Local loss of breeding; risk of mortality. Order of severity: 2 (greatest), 1, 3.

 

All Alternatives.  Potentially significant disturbance of clapper rail foraging, mating, nesting, due to treatment activity, resulting habitat destruction, and crew access to rail habitats. Local loss of breeding; risk of mortality. Order of severity:
2 (greatest), 1, 3.

 

All Alternatives.  Potentially
significant disturbance of clapper rail foraging, mating, nesting, due to treatment activity, resulting habitat destruction, and crew access to rail habitats. Local loss of breeding; risk of mortality. Greater severity for Alternative 2.

 

 

All Alternatives.  Potentially
significant disturbance of clapper rail foraging, mating, nesting, due to treatment activity, resulting habitat destruction, and crew access to rail habitats. Local loss of breeding; risk of mortality. Greater severity for Alternatives 1 & 2.

 

Alternatives 1, 3.  Potentially
significant disturbance of clapper rail foraging, mating, nesting, due to treatment activity, resulting habitat destruction, and crew access to rail habitats. Local loss of breeding; risk of mortality. Greater severity for Alternative 1.

Alternative 2:
No impact.

 

Alternative 1:
Long- term protection and restoration of typical tidal creek and marsh habitat structure to which the subspecies is adapted.

Alternatives 2, 3: Delayed loss of typical habitat structure, eventual significant net
expansion of
suitable habitat of uncertain long-term stability.

 

BIO-5.2: Effects on
the California
black rail.

All Alternatives: Potentially significant impact foreseeable only at one site; no impacts in San Francisco Bay.

 

All Alternatives: Potentially significant impact foreseeable only at one site; no impacts in San Francisco Bay.

 

All Alternatives: Potentially significant impact foreseeable only at one site; no impacts in San Francisco Bay.

 

All Alternatives: Method probably inapplicable to
existing or foreseeable San Pablo Bay infestations; no impacts in San Francisco Bay.

 

All Alternatives: Method probably inapplicable to
existing or foreseeable San Pablo Bay infestations; no impacts in San Francisco Bay.

 

All Alternatives: Potentially significant impact foreseeable only at one site; no impacts in San Francisco Bay.

 

Alternative 1:
Probable long-term, widespread
cumulative benefit due to arrest of invasions by non-native cordgrass, protection of
habitat. Significant long-term benefit.

Alternatives 2-3: No long-term
benefits (invasion likely to overtake eradication).

 

BIO-5.3: Effects on tidal marsh song sparrow subspecies and the salt marsh common
yellowthroat.

All Alternatives:  Potentially significant disturbance of foraging, mating, nesting, due to treatment activity, resulting habitat destruction, and crew access to habitats. Local loss of breeding; risk of mortality. Order of severity: 2 (greatest), 1, 3.

 

All Alternatives:  Potentially significant disturbance of foraging, mating, nesting, due to treatment activity, resulting habitat destruction, and crew access to habitats. Local loss of breeding; risk of mortality. Order of severity: 2 (greatest), 1, 3.

 

All Alternatives:  Potentially significant disturbance of foraging, mating, nesting, due to treatment activity, resulting habitat destruction, and crew access to habitats. Local loss of breeding; risk of mortality. Order of severity: 2 (greatest), 1, 3A.

 

Alternatives 1-2.  Potentially significant disturbance of foraging, mating, nesting, due to treatment activity, resulting in habitat destruction, and crew access to rail habitats. Local loss of breeding; risk of mortality. Greater severity for Alternative 2.

Alternative 3A: Potentially
significant adverse impact if used.

 

All Alternatives:  Potentially significant disturbance of foraging, mating, nesting, due to treatment activity, resulting habitat destruction, and crew access to habitats. Local loss of breeding; risk of mortality. Order of severity: 2 (greatest), 1, 3A.

 

Alternatives 1 & 3:  Potentially significant disturbance of foraging, mating, nesting, due to treatment activity, resulting habitat destruction, and crew access to habitats. Local loss of breeding; risk of mortality. Greater severity for Alternative 1 than for Alternative 3.

Alternative 2:
No impact.

 

Alternative 1:
Long- term protection and restoration of typical tidal creek edge and marsh plainhabitat structure to which these subspecies are adapted.

Alternatives 2, 3: delayed loss of typical habitat structure, no long-term benefit.

 

BIO-5.4: Effects on
California least terns and western sn
owy plovers.

Alternative 1:
Potentially significant local adverse impacts to levee nest sites due to vehicle access. 

Alternative 2:
Greater impact than Alternative 1.

Alternative 3: Less impact than Alternative 1, but still potentially significant.

 

Alternative 1:
Potentially significant local adverse
impacts to levee nest sites due to vehicle access.
Potential minor to moderate turbidity impacts on tern foraging due to intertidal dredging, excavation.

Alternative 2:
Greater impact than Alternative 1.

Alternative 3: Less impact than Alternative 1, potentially significant.

 

Alternative 1:
Potentially significant local adverse
impacts to levee nest sites due to vehicle access. 

Alternative 2:
Greater impact than Alternative 1.

Alternative 3: Less impact than
Alternative 1,
potentially significant.

 

Alternative 1:
Potentially significant local adverse impacts to levee nest sites due to vehicle access. 

Alternative 2:
Greater impact than Alternative 1.

Alternative 3:
If used, impacts minor or no impacts at most sites.

 

Alternative 1:
Potentially significant local adverse impacts to levee nest sites due to vehicle access.

Alternative 2:
Greater impact than Alternative 1.

Alternative 3:
If used, impacts may be significant at a few potential project sites, but minor or no impacts at most sites.

 

Alternative 1:
Potentially significant local adverse impacts to levee nest sites due to vehicle access. 

Alternative 2:
No impacts

Alternative 3:
Less impact than Alternative 1, potentially significant.

 

 

Alternatives 1, 2:
Long-term moderate potential benefits for additional restored estuarine beach habitats, avoidance of salt pond intake obstruction by massive cordgrass wracks.

Alternative 3: Short-term benefits, no long-term benefits.

 

BIO-5.5: Effects on raptors (birds of prey).

All alternatives: minor short-term or no impact.

All alternatives: minor short-term or no impact.

All alternatives: minor short-term or no impact.

All alternatives: minor short-term or no impact.

All alternatives: minor short-term or no impact.

Alternatives 1, 3: Potential moderate adverse impacts if helicopters are used, otherwise minor short-term impacts.

Alternative 2:
No impact.

Alternative 1:
Long- term protection and restoration of
typical tidal creek edge and marsh plain-habitat
structure to which these subspecies are adapted.
Moderate to
significant benefit of stabilizing pickleweed-dominated marsh plains.

Alternatives 2, 3: Delayed loss of typical habitat structure, no long-term benefits.

 

BIO-6.1: Effects on
anadromous
salmonids (winter-run and spring-run Chinook salmon, steelhead).

All Alternatives: minor short-term impact or none.

 

Alternative 1:
Potential minor to moderate adverse impacts of dredging in tidal creeks or channels at low tide, due to elevated turbidity, dissolved sulfides, reduced dissolved oxygen; South Bay only.

Alternative 2:
Impacts greater than Alternative 1, but less than
significant.

Alternative 3: Similar to Alternative 1, less impact.

 

All Alternatives: minor short-term impact or none.

 

Alternative 1:
Minor to moderate potential entrainment and trapping impact within impounded areas, less than ongoing salt pond operations in
region; South Bay only.

Alternative 2:
Impacts greater than Alternative 1, but less than significant.

All Alternatives: minor short-term impact or none.

 

Alternative 1:
Minor to moderate impact due to potential exposure of fish to tidally remobilized herbicide spray solution containing surfactants.

Alternative 2:
No impact.

Alternative 3:
Less impact than Alternative 1.

 

Alternative 1:
Long-term stabilization and restoration of natural tidal creek structure and high density of small tidal creeks due to arrested spread of smooth cordgrass, protection of favorable habitat.

Alternatives 2, 3: Delayed degradation of tidal creek habitat quality and abundance, no long-term benefit.

 

BIO-6.2: Effects on delta smelt and Sacramento splittail.

All Alternatives: Minor short-term impact or none.

 

All Alternatives: Minor short-term impact or none.

 

All Alternatives: Minor short-term impact or none.

 

All Alternatives: Method probably inapplicable to North Bay geographic range of these species.

 

All Alternatives: Minor short-term impact or none.

 

Alternative 1: Long-term stabilization and restoration of natural tidal creek structure and high density of small tidal creeks due to arrested spread of smooth cordgrass, protection of favorable habitat.

Alternatives 2, 3: Delayed degradation of tidal creek
habitat quality and abundance, no long-term benefit.

 

All alternatives: No benefits.

BIO-6.3: Effects on the tidewater goby.

All Alternatives:
No impact.

All Alternatives:
No impact.

All Alternatives:
No impact.

All Alternatives:
No impact.

All Alternatives:
No impact.

All Alternatives:
No impact.

All alternatives:
No benefits.

BIO-6.4: Effects on
estuarine fish populations of shallow submerged intertidal mudflats and channels.

All Alternatives: Minor short-term impact or none.

 

Alternative 1:
Potential minor to moderate adverse impacts of dredging in tidal creeks or channels at low tide, due to elevated turbidity, dissolved sulfides, reduced dissolved oxygen; South Bay only.

Alternative 2:
Impacts greater than Alternative 1, but less than significant.

Alternative 3: Similar to
Alternative 1,
less impact.

 

All Alternatives: Minor short-term impact or none.

 

Alternative 1: Minor to moderate potential entrainment and trapping impact within impounded areas, less than ongoing salt pond operations in
region; South Bay only.

Alternative 2:
Impacts greater than Alternative 1, but less than
significant.

Alternative 3: similar to Alternative 1, less impact.

 

All Alternatives: Minor short-term impact or none.

 

Alternative 1: Minor to moderate impact due to potential exposure of fish to tidally remobilized herbicide spray solution containing surfactants.

Alternative 2:
Impacts greater than Alternative 1, but less than
significant.

Alternative 3: similar to Alternative 1, less impact.

 

Alternative 1: Long-term stabilization and restoration of natural tidal creek structure and high density of small tidal creeks due to arrested spread of smooth cordgrass, protection of favorable habitat.

Alternatives 2, 3: Delayed degradation of tidal creek
habitat quality and abundance, no long-term benefit.

 

BIO-7: Effects on
California red-legged frog and San Francisco
garter snake.

All alternatives:
No impacts.

All alternatives:
No impacts.

All alternatives:
No impacts.

All alternatives:
No impacts.

All alternatives:
No impacts.

All alternatives:
No impacts.

All alternatives:
No benefits.

BIO-8: Effects of regional invasive cordgrass
eradication
on mosquito
production.

All Alternatives: Minor to moderate production of additional mosquito breeding habitat in topographic depressions in marsh plain left by vehicles, excavation pits.

 

All Alternatives: Minor to moderate production of additional mosquito breeding habitat in topographic depressions in marsh plain left by vehicles, excavation pits.

 

All Alternatives: Minor to moderate production of
additional mosquito breeding habitat in topographic depressions in marsh plain left by vehicles, excavation pits.

 

Alternative 1:
No impact from large impounded or deeply flooded areas; moderate potential for
additional new breeding habitat in small, shallow hypersaline impoundments.

Alternative 2:
Similar to Alternative 1, greater impact.

Alternative 3: Similar to Alternative 1, ess impact.

 

All Alternatives: Minor to moderate production of additional mosquito breeding habitat in topographic
depressions in marsh plain left
by vehicles,
excavation pits.

 

All Alternatives: Minor to moderate production of
additional mosquito breeding habitat in topographic
depressions in marsh plain left
by vehicles,
excavation pits.

 

Alternative 1:
Long-term avoidance of risk that poorly drained "short form" smooth cordgrass plains would
increase mosquito production,
comparable to
Atlantic coastal marshes.  Potential significant benefit.

Alternatives 2, 3: Delay in risk of habitat modification favoring mosquito production, no long-term benefit.

 

BIO-9: Effects on tiger beetle species.

All alternatives:  No impact.

 

All alternatives:  No impact.

 

All alternatives:  No impact.

 

All alternatives:  No impact.

All alternatives:  No impact.

 

All alternatives:  No impact.

Alternatives 1, 2: Beneficial impact because potential habitat for tiger beetle species would increase.

 



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