Environmental Assessment for Invasive Plant Species Control
Merced and San Joaquin River National Wildlife Refuges
September 2020
Estimated Lead Agency Total Costs Associated with Developing and Producing This Environmental Assessment - $12,000
Environmental Assessment for Invasive Plant Species Control
Merced and San Joaquin River National Wildlife Refuges
September 2020
This Environmental Assessment (EA) is being prepared to evaluate the effects associated with this proposed action and complies with the National Environmental Policy Act (NEPA) in accordance with Council on Environmental Quality regulations (40 CFR 1500-1509) and Department of the Interior (43 CFR 46; 516 DM 8) and U.S. Fish and Wildlife Service (550 FW 3) regulations and policies. NEPA requires examination of the effects of proposed actions on the natural and human environment.
Proposed Action The U.S. Fish and Wildlife Service (Service) proposes to inventory and control three critical invasive plant threats on the San Joaquin River and the Merced National Wildlife Refuges (Refuge or NWR). The final decision on the proposed action will be made at the conclusion of the public comment period for the EA.
Background National Wildlife Refuges are guided by the mission and goals of the National Wildlife Refuge System (NWRS), the purposes of an individual refuge, Service policy, and laws and international treaties. Relevant guidance includes the National Wildlife Refuge System Administration Act of 1966, as amended by the National Wildlife Refuge System Improvement Act of 1997, Refuge Recreation Act of 1962, and selected portions of the Code of Federal Regulations and Fish and Wildlife Service Manual.
The Merced Refuge was established in 1951, under the authority of the Lea Act and Migratory Bird Conservation Act. Under the Lea Act, a founding purpose of the Refuge was to attract waterfowl away from adjacent agricultural land where major crop depredation was occurring. In the last few decades, changes in local agricultural practices and refuge management activities have reduced these wildlife/crop issues. Additional lands have also been acquired under the authority of the Endangered Species Act of 1973. The Refuge emphasizes managing and conserving migratory birds, endangered species, and key, rare and endemic species native to the diverse habitats of the northern San Joaquin Valley. The Refuge consist of four main units: Merced, Lonetree, Snobird, and Arena Plains.
The San Joaquin River Refuge was established in 1987 to provide winter forage and roosting habitat for the threatened Aleutian cackling goose, protect other species federally listed as endangered/threatened, improve and manage habitat for migratory birds and conserve native fauna and flora. The San Joaquin
River Refuge was established under authority of the Endangered Species Act of 1973, Migratory Bird Conservation Act of 1929, and the Fish and Wildlife Act of 1956.
The mission of the NWRS, as outlined by the National Wildlife Refuge System Administration Act (NWRSAA), as amended by the National Wildlife Refuge System Improvement Act (16 U.S.C. 668dd et seq.), is to:
“... to administer a national network of lands and waters for the conservation, management and, where appropriate, restoration of the fish, wildlife, and plant resources and their habitats within the United States for the benefit of present and future generations of Americans”
The NWRSAA mandates the Secretary of the Interior in administering the System to (16 U.S.C. 668dd (a) (4):
• Provide for the conservation of fish, wildlife, and plants, and their habitats within the NWRS; • Ensure that the biological integrity, diversity, and environmental health of the NWRS are
maintained for the benefit of present and future generations of Americans; • Ensure that the mission of the NWRS described at 16 U.S.C. 668dd(a)(2) and the purposes of
each refuge are carried out; • Ensure effective coordination, interaction, and cooperation with owners of land adjoining refuges
and the fish and wildlife agency of the States in which the units of the NWRS are located; • Assist in the maintenance of adequate water quantity and water quality to fulfill the mission of the
NWRS and the purposes of each refuge; • Recognize compatible wildlife-dependent recreational uses as the priority general public uses of
the NWRS through which the American public can develop an appreciation for fish and wildlife; • Ensure that opportunities are provided within the NWRS for compatible wildlife-dependent
recreational uses; and • Monitor the status and trends of fish, wildlife, and plants in each refuge.
Therefore, it is a priority of the Service to conserve and manage fish, wildlife, and plants, and their habitats consistent with the purposes for which the refuge was established and the mission of the National Wildlife Refuge System.
Purpose and Need for the Proposed Action The purpose of this proposed action is to contain or suppress the invasive giant reed/Arundo (Arundo donax), tree of heaven (Ailanthus altissima), and tree tobacco (Nicotiana glauca) on the San Joaquin River and Merced NWRs.
Both the San Joaquin River and Merced Refuges are part of the San Luis NWR Complex. (See Figure 1.) Within the Stanislaus, Tuolumne and San Joaquin river floodplains of the San Luis NWR Complex, several invasive plant species of concern have established pioneer populations following significant flooding in the spring of 2017 and to a lesser extend the spring of 2019. Within the Merced NWR flood bypass, ten individual occurrences of Arundo, tree of heaven, and tree tobacco have been identified. These invasions share the characteristic of occurring in small populations and having been found by refuge staff conducting basic preliminary searches for new invasive populations. As these invasive plants are believed to be in small numbers and isolated populations, and early detection inventory coupled with a rapid chemical and mechanical suppression response could result in control or eradication of these species
Figure 1. Location of Merced and San Joaquin River National Wildlife Refuges
within refuge boundaries for the foreseeable future. The foreseeable future is defined as the next significant flooding event, which generally occur once a decade.
Resources of conservation concern within the riparian corridors and floodplains of the Merced and San Joaquin NWRs include the critically endangered riparian brush rabbit, the endangered riparian wood rat and the endangered least Bell’s vireo. Changes to the vegetative composition and structure of these flood plain habitats, particularly an expansion of Arundo monocultures, could threaten the critical habitat these species depend upon.
Alternatives Considered Alternative A – No Action Alternative Under the No Action Alternative, the Service would take no project specific action to control giant reed/Arundo, tree of heaven, or tree tobacco. However, the Service would continue to operate and maintain both the Merced and San Joaquin River Refuges. As part of refuge management, the Service would continue to manage invasive plant species through an integrated pest management approach (IPM). IPM involves using control methods based on effectiveness, cost, and minimal ecological disruption, which considered minimum potential effects to non-target species and the refuge environment. Pesticides may be used where physical cultural, and biological methods or combinations thereof, are impractical or incapable of providing adequate control, eradication, or containment. Pesticide use is allowed in accordance with 517 DM1, and only after approved through the Service’s Pesticide Use Proposal (PUP) process.
Service-approved herbicides would continue to be used for controlling invasive plants. Plants targeted for treatment include: California bulrush, common cattail, common cocklebur, water primrose, water-hyacinth, black mustard, common mallow, Johnson grass, mild thistle, poison hemlock, Russian thistle, cheese weed, prickly lettuce, yellow star thistle, perennial pepperweed, salt cedar, tree of heaven, and tree tobacco. The active ingredients in herbicides expected to be used include: glyphosate (both terrestrial and aquatic formulations), triclopyr trimethylamine, aminopyralid, chlorsulfuron, dicamba, nicosulfuron, and rimsulfuron. Over the past three years, pesticide application on Merced NWR has ranged from approximately 250 acres to 465 acres, and application of pesticides on San Joaquin River NWR has ranged from 490 acres to 552 acres.
Mitigation Measures to Avoid Conflicts The following best management practices would be used when applying pesticides to control invasive plant species:
• General: o All chemical treatments would comply with the applicable federal and state regulations
pertaining to pesticide use, safety, storage, disposal, and reporting. o Before pesticides can be used to eradicate or control invasive plant species on Service
owned land, a PUP would be prepared and approved in accordance with 569 FW1. o Application equipment will be selected to provide site-specific delivery to target pests
while minimizing/eliminating direct or indirect (e.g., drift) exposure to non-target areas. o Target-specific equipment will be used to treat pests. o Only qualified personnel may apply pesticides. o Chemical treatments will be applied during calm, dry weather and an unsprayed buffer
would be maintained near any sensitive areas.
o Seasonal wetlands would be treated only when dry. o Chemical applications must be avoided where seasonal precipitation or excess irrigation
water is likely to wash residual chemicals into waterways. o All chemicals will be handled in strict accordance to label specifications.
• Pesticide Handling and Mixing: o As a precaution against spilling, spray tanks shall not be left unattended during filling. o All pesticide containers shall be triple rinsed and the rinsate would be used as water in the
sprayer tank and applied to treatment areas. o All pesticide spray equipment shall be properly cleaned. Where possible, rinsate should
be used as a part of the make-up water in the sprayer tank and applied to treatment areas. o Pesticide containers shall be triple rinsed and recycled (where feasible). o All unused pesticides shall be properly discarded at a local “safe send” collection site. o Pesticides and pesticide containers shall be lawfully stored, handled, and disposed of in
accordance with the label and in a manner safeguarding human health, fish, and wildlife, soil, and water.
o Where specified on the pesticide label, water quality parameters (e.g., pH and hardness) that are important to ensure greatest efficacy shall be considered.
o All pesticide spills shall be addressed immediately using procedures identified in the refuge spill response plan.
• Applying Pesticides: o Pesticide treatments shall only be conducted by or under the supervision of Service
personnel and non-Service applicator with the appropriate state certification to safely and effectively conduct these activities on refuge lands and waters.
o All Federal, state, and local pesticide use laws and regulations as well as Departmental, Service, and NWRS pesticide-related policies shall be complied with. For example, as required under FIFRA, the proper application equipment and rates should be used for the specific pest(s) identified on the pesticide label.
o Low-impact herbicide application techniques (e.g., spot treatment, cut stump, oil basal, and Thinvert system applications) rather than broadcast foliar application (e.g., boom sprayer and other larger tank wand applications) shall be used, where practical.
o To maximize herbicide effectiveness and ensure correct and uniform application rates, low-volume rather than high-volume foliar applications shall be used where the low-impact methods above are not feasible or practical.
o Applicators shall use and adjust spray equipment to apply the coarsest droplet size spectrum with optimal coverage of the target species while reducing drift.
o Applicators should use the largest droplet size that results in uniform coverage. o Applicators shall use drift reduction technologies such as low-drift nozzles, unless
otherwise authorized by the refuge manager. o Where possible, spraying shall occur during low (average <7mph and preferably 3 to 5
mph) and consistent direction wind conditions with moderate temperatures (typically <85oF).
o Where possible, applicators shall avoid spraying during inversion conditions (often associated with calm and very low wind conditions) that can cause large-scale herbicide drift to non-target areas.
o Equipment shall be calibrated regularly to ensure that the proper rate of pesticide is applied to the target area or species.
o Spray applications shall be made at the lowest height for uniform coverage of target pests to minimize/eliminate potential drift.
o If windy conditions frequently occur during afternoons, spraying (especially boom treatments) shall typically be conducted during early morning hours.
o Spray applications shall not be conducted on days with >30% forecast for rain within 6 hours, except for pesticides that are rapidly rain fast (e.g., glyphosate in 1 hour) to minimize/eliminate potential runoff.
o Where possible, applicators shall use drift retardant adjuvants during spray applications, especially adjacent to sensitive areas.
o Where possible, applicators shall use a non-toxic dye to aid in identifying target area treated as well as potential overspray or drift. A dye can also aid in detecting equipment leaks. If a leak is discovered, the application shall be stopped until repairs can be made to the sprayer.
o For pesticide uses associated with cropland and facilities management, buffers, as required in PUPS, shall be used to protect sensitive habitats, especially wetlands and other aquatic habitats.
o When drift cannot be sufficiently reduced through altering equipment set up and application techniques, buffer zones shall be identified to protect sensitive areas downwind of applications.
o Applicators shall utilize scouting for early detection of pests to eliminate unnecessary pesticide applications.
o The timing of applications shall be considered so native plants are protected (e.g., senescence) while effectively treating invasive plants.
o Rinsate from cleaning spray equipment shall be recaptured and reused or applied to an appropriate pest plant infestation.
o Application equipment (e.g., sprayer, ATV, tractor) shall be thoroughly cleaned and PPE removed/disposed of on-site by applicators after treatments to eliminate the potential spread of pests to un-infested areas.
• Safety: o All applicators should wear the specific personal protective equipment (PPE) identified
on the pesticide label. The appropriate PPE should be worn at all times during handling, mixing, and applying. PPE can include the following: disposable (e.g., Tyvek) or laundered coveralls; gloves (latex, rubber, or nitrile); rubber boots; and an NIOSH-approved respirator. Because exposure to concentrated product is usually greatest during mixing, extra care should be taken while preparing pesticide solutions. Persons mixing these solutions can be best protected if they wear long gloves, and apron, footwear, and a face shield.
o Transporting, storing, handling, mixing, and disposing or pesticide containers should be consistent with label requirements, USEPA and OSHA requirements, and Service policy.
In addition, the Service has prepared chemical profiles of the active ingredients in pesticides to guide their application on Service managed lands. Appendix 1 contains the full chemical profile of each active ingredient. The Service uses the specific best management practices contained in the chemical profiles contained in Appendix 1.
Alternative B – Proposed Action Alternative Under the Proposed Action Alternative the Service would take the following actions:
• Inventory and map the Arundo, tree of heaven, and tree tobacco on Merced and San Joaquin River NWRs in the entire grid-based survey area by October 15, 2020, using a contracted ground crew.
• Treat and control all mapped populations of Arundo, tree of heaven and tree tobacco on Merced and San Joaquin River NWRs by October 31, 2020. (See Figures 2 and 3.) The estimated total area of all populations of these three species on Merced and San Joaquin River NWRs is less than three acres. Fewer than 30 individual occurrences of all three species combined have been documented on both refuges. Control techniques are as follows:
o For Arundo, control techniques will be in accordance with published guidance from Weed Control in Natural Areas (Tu et al. 2001). Following detection, Arundo that can be accessed by the Service’s heavy equipment will be removed via backhoe, including the rhizome mass. Excavation of the rhizome would be two to three feet deep and each site would be backfilled to the previous ground level. All removed plant material would be taken to a burn pile and burned by the Service. In areas not accessible by heavy equipment, standing stalks will be cut and removed to a burn pile. An herbicide mix of 1 part imazapyr plus 1 quart glyphosate product per acre will be applied with the late summer/fall window recommended.
o For tree tobacco, control techniques will be in accordance with published guidance from Weed Control in Natural Areas. The cut stump methodology on trees greater than 3”dbh (diameter at breast height) will be used. The cut stumps will be treated with a 50 percent Garlon 4 Ultra in 20 percent oil and water mix. For trees less than 3” dbh, the basal bark method will be used, with a 20 percent Garlon 4 Ultra in 20 percent oil/water mixture.
o For the tree of heaven, control follows the same technique recommendations at Tree tobacco, with specific guidance based on the U.S. Forest Service publication TP-R3-16-09 (USFS 2017) Field Guide for Managing Tree of Heaven in the Southwest.
Mitigation Measures to Avoid Conflicts The same mitigation measures listed under the No Action Alternative would also be used under the Proposed Action Alternative. In addition, under the Proposed Action Alternative, the Service would use a mix of imazapyr and glyphosate to treat Arundo in accordance with the specific best management practices listed in the chemical profiles included in Appendix 1. When combination products are used on Service lands, the most restrictive BMPs are implemented.
Affected Environment and Environmental Consequences This section describes both the affected environment and the environmental consequences of each alternative.
The Merced NWR is located in Merced County approximately 15 miles southwest of the city of Merced, situated on the floodplain of Bear Creek and other tributaries of the San Joaquin River. (See Figure 1). The Refuge encompasses over 10,260 acres of freshwater wetlands, native uplands, agricultural fields, vernal pools, and riparian corridors. Although Merced NWR is an important area for migratory
Figure 2. Location of Giant Reed, Tree of Heaven, and Tree Tobacco on San Joaquin River National Wildlife Refuge
Figure 3. Location of Giant Reed on Merced National Wildlife Refuge
waterbirds and assemblages or other native wildlife, it plays a major role in supporting the largest numbers of wintering Ross’ (Anser rossii) and snow geese (Anser caerulescens) and lesser sandhill cranes (Grus canadensis) along the Pacific Flyway. Each winter, as many as 50,000 white geese and 20,000 cranes will use this Refuge.
The San Joaquin River Refuge is nine miles west of the City of Modesto, and straddles western Stanislaus and San Joaquin counties. The 11,397 acres within the Refuge are along the main stem of the San Joaquin River from just south of the confluence with the Tuolumne River, then north to the south bank of the Stanislaus River. The Refuge’s landscape represents a locally – as well as regionally – significant remnant of the once broad floodplain of these three major rivers of California’s Central Valley. Surrounding lands are largely used in agricultural production.
This EA only includes the written analyses of the environmental consequences on a resource when the impacts on that resource could be more than negligible and therefore considered an “affected resource”. Any resources that will not be more than negligibly impacted by the action have been dismissed from further analyses. These resource topics include noise, transportation, the social and economic environment, and visitor services.
Impact Types:
• Direct effects are those which are caused by the action and occur at the same time and place. • Indirect effects are those which are caused by the action and are later in time or farther removed
in distance, but are still reasonably foreseeable. • Cumulative impacts result from the incremental impact of the action when added to other past,
present, and reasonably foreseeable future actions regardless of what agency (federal or non-federal) or person undertakes such other actions.
Affected Natural Resources and Anticipated Impacts of the Alternatives Soils The soils of the Central Valley are mostly Entisols and Alfisols. Schoenherr (1992) provides a broad overview of the soils and geology of the Central Valley:
“The Central Valley is a huge basin filled with sediments. The deepest parts of the gravels and sands are marine sediments that have accumulated since the late Jurassic – 145 million years ago. The sea retreated from the Central Valley at about the same
time that the southern Coast Ranges were uplifted, and during the long history of accumulation of marine sediments in the valley, the basement rock continued to
subside. During most of the Pleistocene the area was occupied by shallow brackish and freshwater lakes. During the last 5 million years, sediments accumulated as
alluvial deposits washed out of the mountains. These deposits are only a few thousand feet deep over most of the valley floor.”
Physical conditions on the Merced and San Joaquin River NWRs consists primarily of recent alluvial floodplains and basin lands. Soil types are often mixed alluvium mapped as soil associations. Basin soils are affected by highwater tables from river water seepage, as well as saturation of the land by deep penetration of rain and irrigation water. Most soils exhibit very poor drainage, with a high water table at a depth of just three to six feet from December to April (Arkley 1964).
Alternative A –No Action Alternative The Service would continue to use herbicides for refuge management on the Merced and San Joaquin River Refuges as needed. The Service treats between 250 and 465 acres on Merced Refuge and approximately 500 acres on San Joaquin River Refuge annually. The active ingredients in the herbicides used most recently include glyphosate, dicamba, nicosulfuron, rimsulfuron, triclopy, aminopyralid, and chorsulfuron. All of the active ingredients used on the refuges are degraded primarily by microbial metabolism in soils and are not expected to persist in soils from one year to the next (Tu et al. 2001). For example, glyphosate rapidly and strongly adheres to soil and degrades, especially in areas with high organic content; thus, little is transferred by rain or irrigation water and there would be a minute leaching potential from application (Suave et al. 2005). Glyphosate also dissipates rapidly from natural water bodies through adsorption to the organic substances and inorganic clays, microbial degradation, and dilution. These characteristics mean that application has only short-term minor adverse effects on soils. All of these herbicides are applied in accordance with the label, are commonly used for invasive species control, and are not persistent in the environment. Under most environmental conditions the field half-life for these herbicides ranges from 0.2 days to 26 days (USFS 2004; 2007; 2011a, b). These herbicides would be applied in upland areas and/or dry habitat for seasonal wetlands and with sufficient buffer from riparian and aquatic habitat; thereby reducing the potential for soil erosion transport. Given these characteristics and management controls, the application of herbicides would have only a minor adverse effect on soils.
Alternative B – Proposed Action Alternative Soils on the Merced and San Joaquin River NWRs could be disturbed by both heavy equipment and pesticide use. Where accessible, Arundo (including the rhizome mass) would be removed with a backhoe and the site would be backfilled to the previous ground level. Mobilization of the backhoe and Arundo removal would cause localized soil disturbance. Where Arundo is not accessible to heavy equipment, all standing stalks would be cut to the ground and an herbicide mix of imazapyr and glyphosate would be applied. Imazapyr is a non-selective herbicide that is degraded primarily by microbial metabolism in soils. The half-life of imazapyr in soil ranges from one to five months. Under most field conditions imazapyr does not bind strongly to soils and can be highly available in the environment (Tue et al 2001). Glyphosate as described under the No Action Alternative would have only a minor adverse effect on soils. Under the Proposed Action, application of the mix of imazapyr and glyphosate would only take place where removal of Arundo is not possible with heavy equipment.
On the San Joaquin River NWR, both tree of heaven and tree tobacco would be removed by cutting trees greater than 3”dbh (diameter at breast height) and then treating the stump with a 50 percent Garlon 4 Ultra (triclopyr) in 20 percent oil and water mix. For trees less than 3” dbh, the basal bark method will be used, with a 20 percent Garlon 4 Ultra (triclopyr) in 20 percent oil/water mixture. The basal bark herbicide treatment is a control method in which an oil soluble herbicide is mixed with an oil carrier and applied directly to the bark of a woody plant. Triclopyr is a selective systemic herbicide used to control woody and herbaceous broadleaf plants. The average half-life in soil is 30 days. Application of the herbicide on these plant species is restricted to the cut stump or the bark of the tree.
In summary, the impacts of the proposed action to soils would be minimal. There would be minor, localized soil disturbance from removing the Arundo with a backhoe. The effects of herbicide application would also be minimal because of the targeted application and management controls.
Water Resources Natural hydrology in the northern San Joaquin Valley has been severely altered with the settlement of the area. Natural flows and quality of the water have been significantly impacted. The vast majority of the water used on the refuge Complex is delivered by local water districts through delivery and/or drain canals or is from groundwater at the refuge units. The San Joaquin River which is centrally located in the refuge Complex has little natural flow in this area and immediately upstream is typically dry most of the year.
Water quality in the San Joaquin River is degraded by irrigation drain water and urban runoff during summer and by flushing of accumulated pollutants in urban stormwater and other runoff in the winter. The California State Water Resources Control Board designated 100 miles of the San Joaquin River, including the reach in Merced County, as an impaired water body in 1990 (CVRWQCB 2018). In addition, the lower San Joaquin River from Mendota Pool to Vernalis (130 mile stretch of the River which includes the San Joaquin River Refuge), is currently listed as impaired in accordance with Section 303(d) of the Clean Water Act, for exceeding salinity and boron water quality objectives. Portions of the watershed upstream of the refuges are listed under the Clean Water Act for organophosphorus pesticides, diazinon, chlorpyrifos, and selenium (CVRWQCB/SWRCB 2003). The greatest problems occur on the River and its tributaries upstream of its confluence with the Merced River. At the San Joaquin River Refuge and downstream, relatively cleaner waters from the Merced, Tuolumne, and Stanislaus rivers flow in the San Joaquin River, which improves overall water quality.
The entire San Luis NWR Complex lies within the watershed of the San Joaquin River and the landscape occupied by the refuges has been heavily influenced by the flooding of this major river, which flows northwesterly in an erratic course across the various refuges in the Complex. The San Joaquin River Refuge is bisected by the San Joaquin River, which has flood control levees on both banks. Nearly all San Joaquin River Refuge lands have been separated from river flood water by levees. Except for extreme flood events that result in levee failure, water in the river remains within the levee corridor and does not spread across the floodplain. The Merced Refuge is drained by the Mariposa Bypass, Atwater Drain, and East Bear Creek amongst others. All of these lesser streams and sloughs are tributaries of the San Joaquin River or are drains into the river. Due to the low elevation of Refuge lands and the location of natural river channels, numerous sources of surface water drain onto the Refuge units. Field drains, community ditches and tributaries of the San Joaquin River collect surface and subsurface drainage from nearby agricultural fields. Several irrigation districts that supply irrigation water to upslope farmlands also operate and maintain drainage channels that flow into the Refuge as water proceeds to the river.
Alternative A –No Action Alternative On both the Merced Refuge and the San Joaquin River Refuge, the Service uses herbicides for refuge management. The Service treats between 250 and 465 acres on Merced Refuge and approximately 500 acres on San Joaquin River Refuge annually. The active ingredients in the herbicides used most recently include glyphosate, dicamba, nicosulfuron, rimsulfuron, triclopy, aminopyralid, and chorsulfuron. The Service would maintain unsprayed buffer areas near aquatic and riparian habitat to prevent release to water. Seasonal wetlands would only be treated during dry periods to prevent release to water. All of these herbicides are applied in accordance with the label, are commonly used for invasive species control in upland areas away from water resources, and are not persistent in the environment. Under most environmental conditions the field half-life for these herbicides range from 0.2 days to 26 days (USFS 2004; 2007; 2011a, b). These herbicides would be applied in upland areas and/or dry habitat for seasonal wetlands and with sufficient buffer from riparian and aquatic habitat; thereby reducing the potential for
soil erosion transport. Given these characteristics and management controls, the application of herbicides would have only a short term and minor adverse effect on water resources.
Alternative B –Proposed Action Alternative The Proposed Action could potentially affect water resource by the use of both heavy equipment and pesticides. Where accessible, Arundo (including the rhizome mass) would be removed with a backhoe and the area backfilled to the previous ground level. Mobilization of the backhoe and Arundo removal would cause localized soil disturbance. The Service has located five patches of Arundo on Merced NWR and six patches of Arundo on San Joaquin River NWR. Where Arundo is not accessible to heavy equipment, all standing stalks would be cut to the ground and an herbicide mix of imazapyr and glyphosate would be applied. Imazapyr is a non-selective herbicide that is degraded primarily by microbial metabolism in soils. The half-life of imazapyr in soil ranges from one to five months. Under most field conditions imazapyr does not bind strongly to soils and can be highly available in the environment (Tue et al 2001). Glyphosate as described under the No Action Alternative would have only a minor adverse effect on water resources. Under the Proposed Action, application of the mix of imazapyr and glyphosate would only take place where removal of Arundo is not possible with heavy equipment.
Both tree of heaven and tree tobacco would be removed by cutting trees greater than 3”dbh and then treating the stump with a 50 percent Garlon 4 Ultra (triclopyr) in 20 percent oil and water mix. For trees less than 3” dbh, the basal bark method will be used, with a 20 percent Garlon 4 Ultra (triclopyr) in 20 percent oil/water mixture. The basal bark herbicide treatment is a control method in which an oil soluble herbicide is mixed with an oil carrier and applied directly to the bark of a woody plant. Triclopyr is a selective systemic herbicide used to control woody and herbaceous broadleaf plants. The average half-life in soil is 30 days. Application of the herbicide on these plant species is restricted to the cut stump or the bark of the tree.
In summary, the impacts of the proposed action to water resources would be minimal. The areas where Arundo is removed with a backhoe would be backfilled to the previous ground level and would not be a source of erosion during the rainy season. Herbicides would be applied in upland areas and/or dry habitat for seasonal wetlands and with sufficient buffer from riparian and aquatic habitat; thereby reducing the potential for soil erosion transport. Given the project characteristics and management controls, the excavation of Arundo and application of herbicides would have only a minor adverse effect on water resources.
Vegetation The Central Valley contains three major plant communities – grassland, wetland, and riparian. All of these plant communities occur on both Merced and San Joaquin RiverNWRs.
Habitat types managed by the Merced NWR are: wetland (3,165 acres), riparian (55 acres), and upland (7,042 acres). Wetland habitat comprises about 30 percent of the total acreage and consists of seasonally flooded wetlands and summer wetlands (permanent and semi-permanent wetlands). Riparian habitat is a minor percentage of the total refuge habitat. The approximately 98 vernal pools found on the Arena Plains and Snobird units make up a diverse and distinctive wetland habitat type. Upland habitat is the major component of Refuge habitat and is composed of native perennial grassland, annual grasslands, irrigated pasture, and agricultural crops.
A single Arundo is located in seasonal wetland and the remainder are located in managed riparian in the East Side Bypass.
Habitat types managed by the San Joaquin River Refuge are: wetland (696 acres), riparian (1,919 acres), and upland (3,973 acres). Wetland habitat is about 10 percent of the total acreage and includes permanent, semi-permanent, and seasonal wetlands as well as 4 acres of vernal pools. The upland habitat includes 372 acres of native grasslands, 744 acres of croplands, 506 acres of irrigated pasture, 2,098 acres of fallow land, and 197 acres of irrigation and drainage canals (USFWS 2006). Clumps of Arundo are located in riparian habitat, tree of heaven and tree tobacco are located in riparian areas as well as on fallow and cropland habitats. Tree tobacco can be found along the edge of the West Stanislaus Irrigation District intake canal, along the Refuge boundary, and along Highway 132. Low densities of tree tobacco can also be found on the portions of the Refuge floodplain.
Alternative A –No Action Alternative Use of herbicides as part of refuge management has both short- and long-term positive impacts to native vegetation by controlling invasive and undesirable plant growth that can lead to competitive exclusion of native species. Treatments would be applied predominately in grasslands (e.g., yellow starthistle and milk thistle) and to a lesser extent in both riparian (e.g., common cocklebur and poison hemlock) and wetland habitats (e.g., California bulrush and common cattail). The herbicides that have been approved for use on the refuges through the PUPS are reviewed to determine the potential effect of each herbicide on native vegetation in the event that unintentional pesticide drift should occur. The product and application method with the least potential for impact to native vegetation, while also providing effective control of the pest species, is selected.
The Service treats between 250 and 465 acres on Merced Refuge and approximately 500 acres on San Joaquin River Refuge annually. The active ingredients in the herbicides used most recently include glyphosate, dicamba, nicosulfuron, rimsulfuron, triclopy, aminopyralid, and chorsulfuron. Application of broad spectrum herbicides can result in non-target effects to vegetation from spray drift. For example, glyphosate is a broad-spectrum, non-selective, systemic organophosphate herbicide that is one of the most widely used herbicides in the United States (Benbrook 2016). Modeling and risk assessment studies have shown that indirect exposure (e.g., spray drift) to glyphosate would not be a concern to non-target vegetation beyond a 25 to 100 foot buffer depending on the application rate and weather conditions (USFS 2011a). All of these herbicides are applied in accordance with the label, are commonly used for invasive species control, and are not persistent in the environment. These herbicides would be applied in upland areas and/or dry habitat for seasonal wetlands and with sufficient buffer from riparian and aquatic habitat. Because the Service would follow all pesticide label restrictions and best management practices (see alternative description), an appropriate buffer would be used to minimize spray drift, herbicide application would have only a short term minor direct adverse effect to non-target plant species. Herbicide treatments on invasive plant species would help to minimize weeds in the treatment area as desirable species recolonize and become re-established. This would lead to long-term beneficial effects to native plant species.
Alternative B –Proposed Action Alternative The Proposed Action would have both short- and long-term positive impacts to native vegetation by removing discrete populations of Arundo, tree of heaven and tree tobacco. Arundo clumps that are accessible, would be removed with a backhoe. Those that are not accessible would be cut to the ground and treated with an herbicide mix of imazapyr and glyphosate. Because imazapyr can affect a wide range of plants and can remain available, care must be taken during application to prevent accidental contact with non-target species. As described under the No Action Alternative, spray drift from herbicide application is generally not a concern beyond a 25 to 100 foot buffer depending on the application rate and weather conditions (USFWS 2011).
Both tree of heaven and tree tobacco would be removed by cutting trees greater than 3”dbh (diameter at breast height) and then treating the stump with a 50 percent Garlon 4 Ultra (triclopyr) in 20 percent oil and water mix. Trees less than 3” dbh, would be treated by applying Garlon 4 Ultra directly to the bark of the plant. Under the Proposed Action, the application of the herbicide on each of these plant species is restricted to the cut stump or the bark of the tree.
In summary, the adverse impacts of the proposed action to vegetation would be minimal. These herbicides would be applied directly to the cut stump or the bark of the tree thereby reducing the potential for non-target impacts. As described under the No Action Alternative, the Service would follow all pesticide label restrictions and best management practices (see alternative description), pesticides would not be applied directly to, or within the no-spray buffer of surface waters, and pesticide use is limited to herbicides; therefore, indirect impact to aquatic and terrestrial species that use refuge aquatic resources for food, cover, and nesting would not be likely to occur and the Proposed Action would have only a short term minor direct adverse effect to non-target habitats. The physical removal of Arundo, tree of heaven, and tree tobacco along with herbicide treatments would allow native plant species recolonize and become re-established in the areas now inhabited by these non-native, invasive species. The additional work under the proposed action would facilitate native plant reestablishment over a greater area than the No Action alternative. This would lead to greater long-term beneficial effects to native plant species.
Wildlife California’s diverse terrain and vegetative communities provide conditions for a high degree of wildlife diversity. Both the San Joaquin River and Merced Refuges contain elements of the Central Valley’s three major vegetative types and therefore have the potential to provide habitat for over 325 species of wildlife. Species distribution varies based on the habitat attributes of the different refuge units.
Numerous species of wading and diving birds make use of the wetland, riparian, and upland habitats on the Merced Refuge. Great blue herons (Ardea Herodias), grate egrets (Ardea alba), and double crested cormorants (Phalacrocorax auritus) have established several rookeries in riparian areas. Within wetland units, snowy egrets (Egretta thula), cattle egrets (Bubulcus ibis), and black-crowned night herons (Nycticorax nycticorax) establish roosting and breeding colonies in robust emergent vegetation.
Rodent and rabbit species make up the largest segment, approximately one third, of the mammals found on the Refuges (Eisenberg 1982, USFWS 2018). The two common rabbit species that occur on the Refuges are the desert cottontail (Sylvilagus audubonii) and black-tailed hare (Lepus californicus). Large rodents include the aquatic muskrat (Ondatra zibethicus) and beaver (Castor Canadensis) – both of which play important role in aquatic systems. Dominant rodents, which also act as keystone species because of their grazing/seed predation and/or tunneling, include the deer mouse (Peromyscus maniculatus), California vole (Microtus californicus), and California ground squirrel (Spermophilus beecheyi).
Common carnivores/ominvores include the coyote (Canis latrans), raccoon (Procyon lotor), striped skunk (Mephitis mephitis), northern river otter (Lutra canadensis), longtailed weasel (Mustela frenata), and Virginia opossum (Didelphis virginiana).
The perennial and annual grasslands of the Merced Refuge are managed to provide habitat for: 1) winter foraging habitat for arctic nesting geese, sandhill cranes, and other migrating birds; and 2) year round habitat for the San Joaquin kit fox (Vulpes macrotis mutica), burrowing owls (Athene cunicularia), kangaroo rats (Dipodomys spp.), grassland nesting birds and other short vegetation dependent wildlife species. The Refuge also maintains approximately 395 acres of irrigated pasture with an additional 420
acres managed in corn and winter wheat (270 acres)for the benefit of arctic-nesting geese, sandhill cranes, tri-colored blackbirds, and other migratory birds.
Habitat for fish on the San Joaquin River Refuge includes rivers, permanent wetlands, oxbows, and sloughs. Three major rivers join on the Refuge and provide an important nexus for migratory fish. The stretch of the San Joaquin River and tributaries on the Refuge provide habitat and connectivity to aquatic habitats for a wide range of fish.
Alternative A –No Action Alternative Use of herbicides as part of refuge management has both short- and long-term positive impacts to wildlife species by controlling invasive and undesirable plant growth that can lead to competitive exclusion of native plant species. Treatments would be applied predominately in grasslands (e.g., yellow starthistle and milk thistle) and to a lesser extent in both riparian (e.g., common cocklebur and poison hemlock) and wetland habitats (e.g., California bulrush and common cattail). The herbicides that have been approved for use on the refuges through the PUPS are reviewed to determine the potential effect of each herbicide on native vegetation and associated wildlife in the event that unintentional pesticide drift should occur. The product and application method with the least potential for impact to native vegetation, while also providing effective control of the pest species, is selected.
The Service treats between 250 and 465 acres on Merced Refuge and approximately 500 acres on San Joaquin River Refuge annually. The active ingredients in the herbicides used most recently include glyphosate, dicamba, nicosulfuron, rimsulfuron, triclopy, aminopyralid, and chorsulfuron. Herbicides with these active ingredients are used sparingly, are generally of low toxicity to wildlife, and relatively non-persistent in the aquatic environment (Tu et al. 2001). However, some of the active ingredients in herbicides, such as triclopyr and dicamba, can have negative impacts to bees and other insect pollinators. To minimize this risk, the best management practice is to only apply herbicides with these active ingredients when native plants are not in bloom and when bees and other pollinating insects are less active. Glyphosate is a broad-spectrum, non-selective, systemic organophosphate herbicide that is one of the most widely used herbicides in the United States (Henderson et al. 2010). It has commonly been believed to be relatively non-toxic to non-target organisms such as birds, fish and mammals (Center for Environmental Risk Assessment [CERA] 2002; Folmar et al. 1979). However, studies by Cauble and Wagner (2005), Lanctôt, Robertson, et al (2013), Lanctôt, Navarro-Martin, et al, (2014), Relyea (2005a, 2005b), and Williams and Semlitsch (2010) suggest or demonstrate that glyphosate formulations at concentrations found in the environment can be toxic to amphibians (a taxonomic group that has experienced pronounced population declines globally in recent years). Additionally, the World Health Organization International Agency for Research on Cancer recent categorized glyphosate as, “…probably carcinogenic to humans” (Guyton et al. 2015).
All of these herbicides are applied in accordance with the label, are commonly used for invasive species control, and are not persistent in the environment. Under most environmental conditions the field half-life for these herbicides ranges from 0.2 days to 26 days (USFS 2004; 2007; 2011a, b). These herbicides would be applied in upland areas and/or dry habitat for seasonal wetlands and with sufficient buffer from riparian and aquatic habitat; thereby reducing non-target effects. Because the Service would follow all pesticide label restrictions and best management practices (see alternative description), pesticides would not be applied directly to, or within the no-spray buffer of surface waters, and pesticide use is limited to herbicides, indirect impact to aquatic and terrestrial species that use refuge aquatic resources for food, cover, and nesting would not be likely to occur and would have only a minor direct adverse effect to native wildlife species. The No Action alternative would have beneficial effects on wildlife. By using
herbicides for invasive species control, native plant species can recolonize areas providing greater habitat value for wildlife species.
Alternative B –Proposed Action Alternative The Proposed Action would have similar effect to those described under the No Action alternative. The Proposed Action would have both short- and long-term positive impacts to native vegetation by removing discrete populations of Arundo, tree of heaven and tree tobacco, with minimal direct adverse impacts to wildlife. Arundo, tree of heaven, and tree tobacco provide little wildlife value, therefore there would be minimal direct adverse impacts from their removal. Arundo clumps that are accessible, would be removed with a backhoe. Those that are not accessible would be cut to the ground and treated with an herbicide mix of imazapyr and glyphosate. Glyphosate, as described under the No Action alternative has commonly been believed to be relatively non-toxic to non-target organisms such as birds, fish, and mammals (Center for Environmental Risk Assessment [CERA] 2002; Folmar et al. 1979). However, studies by Cauble and Wagner (2005), Lanctôt, Robertson, et al (2013), Lanctôt, Navarro-Martin, et al, (2014), Relyea (2005a, 2005b), and Williams and Semlitsch (2010) suggest or demonstrate that glyphosate formulations at concentrations found in the environment can be toxic to amphibians (a taxonomic group that has experienced pronounced population declines globally in recent years). Additionally, the World Health Organization International Agency for Research on Cancer recent categorized glyphosate as, “…probably carcinogenic to humans” (Guyton et al. 2015). Imazapyr is of relatively low toxicity to birds and mammals, but some formulations can cause severe, irreversible eye damage (Tu et. al 2001).
The Service would follow all pesticide label restrictions and best management practices (see alternative description), which means that pesticides would not be applied directly to, or within the no-spray buffer of surface waters. In addition, pesticide use is limited to herbicides. Therefore, indirect impact to aquatic and terrestrial species that use refuge aquatic resources for food, cover, and nesting would not be likely to occur and would have only a minor direct adverse effect to native wildlife species.
Because the Proposed Action includes more focused invasive plant control and eradication, the direct effect would temporarily affect a slightly larger area of the Merced and San Joaquin River NWRs (approximately 3 acres). However, the Proposed Action would also have greater beneficial effects to wildlife by removing these invasive plant species that form dense monocultures that degrade wildlife habitat.
Threatened and Endangered Species Several threatened and endangered species occur or have the potential to occur on the refuges. See Table 1.
Table 1. Threatened and Endangered Species on San Joaquin River and Merced Refuges
Species San Joaquin River NWR
Merced NWR Habitat
riparian brush rabbit X Riparian habitat San Joaquin Valley woodrat X Riparian habitat San Joaquin kit fox X X Grasslands Fresno kangaroo rat X Alkali-sink plant associations least Bell’s vireo X X Riparian habitat
Species San Joaquin River NWR
Merced NWR Habitat
giant garter snake X Wetlands valley elderberry longhorn beetle X Riparian habitat blunt-nosed leopard lizard X Alkali sink scrub communities California tiger salamander X X Vernal pools vernal pool fairy shrimp X Vernal pools vernal pool tadpole shrimp
X Vernal pools
conservancy fairy shrimp X Vernal pools longhorn fairy shrimp X Vernal pools colusa grass X Vernal pools hairy orcutt grass X Vernal pools Central Valley steelhead trout
X X
Rivers, permanent wetlands, oxbows, and sloughs
Chinook salmon-winter run X X
Rivers, permanent wetlands, oxbows, and sloughs
The riparian brush rabbit is a subspecies of the brush rabbit. Its original distribution was the most limited of all the brush rabbit subspecies, restricted to a small stretch of the San Joaquin River and some of its tributaries (Orr 1940). Presently the riparian brush rabbit only occurs in three isolated populations, none of which is considered secure for maintaining the long-term status of the population. Through a captive breeding program, a population of brush rabbits has been established at the San Joaquin River NWR and is believed to be the largest such population in the Valley. The riparian brush rabbit is not currently present on the Merced NWR.
Habitat for the endangered San Joaquin kit fox includes arid grasslands in the southern half of the Central Valley. No sightings of kit fox have been documented at the San Joaquin River NWR and the fox’s preferred habitat is scares at the Refuge. Historically, San Joaquin kit fox were apparently very common within the area that now makes up the San Luis NWR, Merced NWR, and the Grasslands WMA. However, Complex monitoring indices that on-refuge kit fox populations have declined over the years. The last documented observation of the species was in March 2000, when a single individual was observed at Merced NWR.
Similar to the riparian brush rabbit, the endangered San Joaquin Valley woodrat required riparian forest as habitat, and in particular, an overstory of oak with a dense woody understory. The woodrat has been documented at the San Joaquin River NWR (USFWS 2006).
The Merced and San Joaquin NWRs s are within the historic range of the Fresno kangaroo rat. Although the species has not been documented on refuge lands, only limited surveys have been conducted, and Fresno kangaroo rats may potentially be present on suitable habitat east of the San Joaquin River. This species is adapted for survival in an arid environment and is found within alkali-sink plant associations.
Nesting by the least bell’s vireo was documented in 2005 and 2006 in a riparian restoration project site at the San Joaquin River NWR. Since that time, this species has been observed nesting recently on both San Luis and Merced NWRs.
The Merced and San Joaquin River NWRs are also within the historic range of the giant garter snake. Although suitable habitat appears to exist on both Merced and San Joaquin River NWRs, there are no documented records for the species. However, only limited surveys have been conducted.
The historic range of the valley elderberry longhorn beetle includes both the San Joaquin River and Merced Refuges; however, the beetle has not been documented to occur on or near either of the Refuges. Habitat for this species (elderberry shrubs) is relatively abundant on the San Joaquin River Refuge east of the San Joaquin River, but limited west of the river. On the Merced Refuge there is little habitat for this species.
The blunt-nosed leopard lizards were present on what is now the Arena Plains Unit of Merced NWR prior to the 1950s (Bert Crane personal communication), but none have been seen in recent years. There is no suitable habitat for this species on the San Joaquin River NWR.
Vernal pool obligate species can be found on both refuges where vernal pools are present. On the San Joaquin River NWR, the vernal pool fairy shrimp and the vernal pool tadpole shrimp have been documented to occur within the refuge vernal pool. The conservancy fairy shrimp and longhorn fairy shrimp are considered potentially present based on habitat availability and the presence of other vernal pool obligate species. The California tiger salamander is also known to occur in vernal pools on the San Joaquin River NWR. Colusa grass has been documented within two vernal pool basins on the Arena Plains unit of Merced NWR. At present only a single population within one of those pools exists. The hairy Orcutt grass, may be present on the Merced NWR, but its current status is unknown.
Habitat for fish species such as Chinook salmon and steelhead trout is limited on the refuges. Dam construction and water diversions upstream of the refuges, beginning in the 1950s, eliminated this historic runs of Chinook salmon and Central Valley steelhead trout. Chinook salmon still occur on a regular basis in the San Joaquin River corridor downstream of the confluence of the Merced River. Due to a lack of suitable habitat, the California Department of Fish and Wildlife operates a fish barrier at the confluence to diver salmon away from the San Joaquin River in to the Merced River where suitable habitat still exists. Despite that, a few salmon get past the barrier and ultimately end up stranded in Salt Slough and Mud Slough where they ultimately die before reaching any spawning habitat.
Alternative A –No Action Alternative The Service would continue to use pesticides to manage invasive weeds. The Service treats between 250 and 465 acres on Merced Refuge and approximately 500 acres on San Joaquin River Refuge annually. The active ingredients in the herbicides used most recently include glyphosate, dicamba, nicosulfuron, rimsulfuron, triclopy, aminopyralid, and chorsulfuron. Herbicides with these active ingredients are used sparingly, are generally of low toxicity to wildlife, and relatively non-persistent in the aquatic environment (Tu et al. 2001). The Service follows all best management practices to minimize any potential effects to sensitive species. The use of herbicides to manage invasive weeds has long term beneficial effects to sensitive species by preventing habitat degradation by these invasive weeds.
Under the No Action Alternative, the Service would not remove the 30 clumps of Arundo, tree of heaven, and tree tobacco and habitat conditions for several listed species on the Refuges could become worse. The riparian brush rabbit, riparian woodrat and least Bell’s vireo are all obligate riparian species, especially during the breeding season. They typically inhabit structurally diverse woodlands along watercourses, including cottonwood-will forests, oak woodlands, and shrub scrub (USFWS 1998a, b). The continued spread of these invasive plants into critical riparian habitats would detrimentally affect short- and long-term survival of these endangered species. During flood years when there is little
available habitat on the San Joaquin River (less than 10 percent), all high ground areas are crucial to proving necessary forage to prevent die-offs from starvation to endangered riparian brush rabbits and riparian woodrats. In a necropsy of rabbits from the refuge during the 2017 flood, almost all of the rabbits tested were in poor body condition, with starvation noted as a contributing factor to the mortality event.
Alternative B – Proposed Action Alternative The Proposed Action would not adversely affect any of the listed species described above. Removal of Arundo with a backhoe and cutting and treating the stems or bark of tree tobacco and tree of heaven is a localized action that would affect less than 3 acres across both refuges. Arundo, tree of heaven, and tree tobacco do not provided habitat for any species listed in Table 1. This work would not be conducted in any sensitive habitats and all label instructions would be followed. No work would be conducted in or near habitat for the valley elderberry longhorn beetle, vernal pool obligate species, the riparian brush rabbit or San Joaquin Valley woodrat, or habitat for the giant garter snake. Application of herbicides is targeted to the cut stump or the bark of the plants and is unlikely to affect habitat for these listed species. Removal of these invasive plant species would take place in late fall when the least Bell’s vireo is not nesting. After Arundo is removed with a backhoe, the area would be backfilled to the previous ground elevation which means that fish would not be caught in these areas after flood events.
Removal of Arundo, tree of heaven, and tree tobacco would prevent these invasive plant species from colonizing riparian habitat that is critical for the riparian brush rabbit, riparian woodrat, and Least Bell’s vireo. Removal of these invasive plant species would have long term beneficial effects to these riparian obligate species.
Air Quality The Merced and San Joaquin River NWRs are located within the San Joaquin Valley Air Pollution Control District (SJAVPCD). The SJAVPCD is made up of eight counties in California’s Central Valley: San Joaquin, Stanislaus, Merced, Madera, Fresno, Kings, Tulare, and the Valley portion of Kern. The entire district is classified as a non-attainment area because it does not meet ambient air quality standards for pollutants. Air pollution within the SJAVPCD comes from a variety of sources. These include industrial facilities, agriculture, vehicles, and consumer products. This pollution is exacerbated by the stagnant air masses that frequent the area. Efforts to reduce emissions from these sources are required by federal and state mandates such as the Federal Clean Air Act Amendments and the California Clean Air Act.
The San Joaquin Valley is the first air basin classified as “serious nonattainment” by the U.S. Environmental Protection Agency to come into attainment of Particulate Matter and the 10 micron level or smaller (PM 10) standards (EPA 2008). However, the San Joaquin Valley is classified as nonattainment for PM 2.5, and 8-Hour Ozone.
Alternative A –No Action Alternative Pesticides are used for refuge management to control invasive plant species. When sprayed, pesticides travel through the air to their intended target. Although generally formulated and propelled to reach and (with the assistance of a surfactant) attach to their target pest, a percentage of some pesticides may volatilize into the air or small pesticide droplets may remain suspended in the air. These effects would be more pronounced with aerial spraying, and less so with ground-level spot spraying, and direct application to stumps. Once airborne, pesticides can move off of the pest control site and drift with the wind or return to surface soils, waters, or plants through precipitation (van Es and Trautmann 1990). High temperatures, low relative humidity, air movement, and small pesticide droplet size all increase volatilization; and
pesticides that tightly adsorb onto soil particles are less likely to volatilize (Fishel 2003). The Service uses all appropriate best management practices to reduce the drift of pesticides such as selecting application equipment to provide site-specific delivery to target pests while minimizing/eliminating direct or indirect (e.g., drift) exposure to non-target areas. The Service’s refuge management would also include the use of heavy equipment and pile burning to control invasive plant species. These activities would have minor adverse impacts to air quality. Emissions of particulates from smoke would generate minor, localized adverse impacts to air quality. All pile burning would be conducted in accordance with the SJVAPCD burn permits.
Alternative B –Proposed Action Alternative Under the Proposed Action, the Arundo that is removed with a backhoe and the tree of heaven and tree tobacco that are cut, would be taken to a Service burn pile and burned. The amount of debris to be burned would be relatively small as there are only 30 occurrences of all three invasive plant species. Pile burning would be conducted in accordance with the SJVAPCD burn permits. Pile burns would result in temporary emissions and minor adverse effects to regional air quality. Pesticide application is targeted to the tree stumps or bark of the trees. The Service would follow all best management practices for pesticide application. These practices will minimize any adverse impacts to air quality.
Cultural Resources and Anticipated Impacts of the Alternatives Cultural resources are physical remains, sites, objects, records, oral testimony, and traditions that connect us to our nation’s history and the land’s past. Cultural resources include archaeological and historical artifacts, sites, landscapes, plants, animals, sacred locations and cultural properties that play an important role in the traditional and continuing life of a community. A formal cultural resources survey was conducted on Merced NWR by Haversat and Breschini in 1985. This survey located one site on Merced NWR. On San Joaquin River NWR, little formal cultural resources survey work has been conducted. The known cultural resources in and within one mile of the acquisition boundary of the San Joaquin River NWR consist of eight prehistoric sites and two historic sites.
Alternative A –No Action Alternative As part of refuge management, the Service would continue to manage invasive plant species through an integrated pest management approach (IPM). IPM involves using control methods based on effectiveness, cost, and minimal ecological disruption, which considered minimum potential effects to non-target species and the refuge environment. Pesticides may be used where physical cultural, and biological methods or combinations thereof, are impractical or incapable of providing adequate control, eradication, or containment. Use of pesticides does not affect cultural resources. When site specific project that include ground disturbing activity are proposed, surveys and other requirements would be followed to minimize the potential for adverse effects to cultural resource sites that have yet to be discovered in accordance with applicable regulations and guidance.
Alternative B –Proposed Action Alternative The potential effect to unknown cultural resources under the Proposed Action Alternative is from the removal of the Arundo by a backhoe. Removal of Arundo with a backhoe would take place in areas that have been previously disturbed. Therefore, the Proposed Action is not likely to adversely affect any cultural resources.
Cumulative Impact Analysis Cumulative impacts are defined as “the impact on the environment which results from the incremental impact of the action when added to other past, present, and reasonably foreseeable future actions
regardless of what agency (Federal or non-Federal) or person undertakes such other actions” (40 CFR 1508.7). This section describes other past, present, and reasonably foreseeable activities impacting the affected environment. For an EA, cumulative impact analysis is done only to a sufficient level to allow the decision maker to make a determination of significance for the proposed action. Thus, the analysis focuses on whether implementation of the proposed action would result in a significant cumulative adverse effect. An important component of this analysis is evaluating other past, present, and reasonably foreseeable actions occurring within the study area that may contribute to cumulative effects.
Development and Population Increase Economic and population growth is a driver for development, leading to an increased need for housing, commercial development, services, transportation, and other infrastructure, which places pressure on the state’s land, water, and other natural resources. California’s population grew by nine percent between the 2000 census and the 2010 census (California Department of Finance 2014). In Merced County, population increased by 46 percent between 1980 and 1995, and continues to grow. Growth and development, including urban, commercial, and industrial development, can exacerbate existing ecosystem pressures, including water management/use. In the Central Valley, 95 percent of historic wetlands are gone (CDFW 2015). Conservation planning on state, federal, and local levels has tempered the ecological effects of growth through conservation and mitigation requirements, such as policies requiring no net loss of California wetlands, and the creation of refuges and reserves for species and habitats (CDFW 2015).
Agricultural Land Uses Sixteen percent of the workforce in Merced County is attributed to agriculture. Merced County’s value of agricultural production in 2017 was $3.408 billion, which ranked 5th among counties statewide (Merced County 2018). A recent study showed that in 2017, agriculture contributed a total of $7.148 billion to the county economy, supporting just over one of every eight jobs in the county (Stanislaus County 2018). Because agriculture dominates land uses in the Central Valley, there are very few remnants of natural habitat remaining (CDFW 2015). Between 1939 to the mid-1980s, agricultural conversion resulted in a net loss of 222.7 thousand acres of wetlands (Frayer, et al., 1989). Agricultural development also contributes to the loss, degradation, and fragmentation of habitats, both terrestrial and aquatic.
Climate Change Warming, whether it results from anthropogenic or natural causes, is expected to affect a variety of natural processes and associated resources. However, the complexity of ecological systems means that there is a tremendous amount of uncertainty about the actual effects of climate change. In particular, the localized effects of climate change are still a matter of much debate. Wildfire risks and intensity has the potential to increase in the coming decades due to climate change and expanded development. Over the next 75 years, a combination of warmer winters, reduced snowpack, earlier snowmelts, and hotter, drier summers would lead to more wildfires in forested parts of the state (DWR 2019). Hydrology has been adversely impacted by flood control and water storage measures, and may be adversely impacted in the coming decades by global and regional climatic events.
Anticipated Cumulative Impacts Implementing the Proposed Action would provide positive benefits to vegetation, wildlife, and special status species. The ecological benefits of the Proposed Action would contribute to the restoration of native habitat that can support numerous wildlife species. The Proposed Action takes place within Service owned land that is managed to conserve and protected native species in an attempt to reduce the
impacts of development and agriculture and the future impacts from climate change. The adverse effects of herbicide application from the proposed action is less than 3 acres across both refuges. Herbicide application is specifically targeted to the stem or bark of the invasive plant species which reduces the potential for non-target species impacts. Therefore the Proposed Action would have only minor adverse cumulative impacts when added to impacts associated with increased development and water competition in the region. While implementing the Proposed Action would provide positive benefits to vegetation, wildlife, and special status species, this alternative would not reverse or halt the regional trend of development and the associated reduction in biological diversity.
Mitigation Measures and Conditions No mitigation measures are proposed other than the avoidance and minimization measures incorporated into the Proposed Action.
Monitoring Service staff will revisit all mapped sites for at least two years after treatment. During these visits any plants missed may also be detected and treated. Ongoing enhancement and restoration of native vegetation will help to deter re-infestation of invasive plants.
Summary of Analysis Alternative A – No Action Alternative Alternative A includes ongoing invasive plant management by refuge staff. Minor adverse effects to soil, water resources, vegetation, wildlife, and threatened and endangered species, would be temporary and localized. Beneficial effects are expected in the long-term where the reduction of invasive plant infestations will facilitate native habitat restoration.
Alternative B – Proposed Action Alternative Under the Proposed Action, the Service would remove an additional 3 acres of invasive plant species on the Merced and San Joaquin River Refuges. The Proposed Action would have only minor adverse effects to soil, water resources, vegetation, wildlife, and threatened and endangered species, would be temporary and localized. Beneficial effects are expected in the long-term where the reduction of invasive plant infestations will facilitate native habitat restoration. In particular, the Proposed Action could improve habitat for the riparian brush rabbit, riparian woodrat and least Bell’s vireo, which are all obligate riparian species, especially during the breeding season.
List of Preparers Patricia Roberson, Natural Resources Division, Refuges, California-Great Basin Region, U. S. Fish and Wildlife Service, Sacramento, CA
State Coordination Coordination with the State will take place during the public outreach period.
Tribal Consultation Coordination with tribes will take place during the public outreach period.
Public Outreach The draft Environmental Assessment will be available to the public and interested agencies for a public review on the Refuge webpages at: Merced National Wildlife Refuge website and San Joaquin River National Wildlife Refuge website. Comments received on the draft document will be addressed as appropriate.
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California Department of Finance, 2014. California County Population Estimates, with components of change and crude rates, Sacramento, CA: s.n.
California Department of Fish and Wildlife (CDFW). 2015. California State Wildlife Action Plan 2015 Update, Sacramento, CA: s.n.
California Department of Water Resources (DWR). 2019. Climate Action Plan, Phase 3: Climate Change Vulnerability Assessment. February 2019. 153 pp.
California Regional Water Quality Control Board, Central Valley Region (CVRWQCB). 2018. The Water Quality Control Plan (Basin Plan) for the California Regional Water Quality Control Board, Central Valley Region. Rancho Cordova, CA. 201 pp.
Cauble, K., and R.S. Wagner. 2005. Sublethal Effects of the Herbicide Glyphosate on Amphibian Metamorphosis and Development. Bulletin of Environmental Contamination and Toxicology 75:429-435.
Center for Environmental Risk Assessment (CERA). 2002. Glyphosate Fact Sheet. Available at: Center for Environmental Risk Assessment.
Central Valley Regional Water Quality Control Board/State Water Resources Control Board (CVRWQCB/SWRCB), “California’s 2002 CWA Section 303(d) List of Water Quality Limited Segments,” California State Water Resources Control Board, Central Valley Region, Rancho Cordova, CA. 2003. Central Valley Regional Water Quality Control Board, Clean Water Act, Section 303(d) List.
Crane, Bert. (Neighboring Landowner) Personal Communication.
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