Attachment 2 - 2019 Invasive Species Monitoring Report_0002.pdf

U.S. Department of the Interior Bureau of Reclamation Technical Service Center Denver, CO September 2019

Invasive Species Monitoring on Disturbed Sites Report

Annual Summer Survey 2019 Folsom Dam, California

Revegetation area looking south from top of Mormon Island Auxiliary Dam.

Mission Statements

The U.S. Department of the Interior protects America’s natural resources and heritage, honors our cultures and tribal communities, and supplies the energy to power our future.

The mission of the Bureau of Reclamation is to manage, develop, and protect water and related resources in an environmentally and economically sound manner in the interest of the American public.

U.S. Department of the Interior Bureau of Reclamation

Denver, CO September 2019

Invasive Species Monitoring on Disturbed Sites Report

Annual Summer Survey 2019 Folsom Dam, California

Report No. ENV-2019-095 prepared by

Rebecca Siegle, Natural Resources Specialist Scott O’Meara, Botanist prepared for

Central California Area Office Folsom, CA

Contents

Page

Introduction Methods Results Literature Cited

Appendices Appendix A – Invasive Plants Location Maps; July 2019 Appendix B – Photo Stations; Summer Surveys July 2017, 2018, and 2019 Appendix C – Invasive Plant Management Recommendations 2019

Tables Table 1. Invasive species included in surveys; Folsom Dam, CA Table 2. Categories used for percent total cover of invasive species Table 3. Number of hectares within which invasive plant species were detected by site and survey period Table 4. Hectares of invasive plant detections by species and cover class in July

2017, 2018, and 2019

Figures Figure 1. Project area Figure 2. Yellow starthistle in flower stage (left) and stinkwort in pre-flower or stem development stage (right) within the Folsom project area Figure 3. Stinkwort seedlings (green plants in photo taken from above) within revegetated areas of Left Wing Dam; July 2018

Introduction As part of the Record of Decision (ROD) of the Folsom Dam Safety and Flood Damage Reduction Final Environmental Impact Statement/Environmental Impact Report, the Bureau of Reclamation (Reclamation) committed to monitoring all revegetated and disturbed areas for invasive, non-native plant species following construction activities. If monitoring determined that invasive species were becoming established on the areas disturbed by project activities, Reclamation also committed to removing the invasive species. A draft Integrated Pest Management (IPM) Plan was produced in 2016 (O’Meara 2016) to provide programmatic guidelines and viable management options for invasive weed treatments. The focus of this report is to provide maps of noxious weed locations with an associated treatment plan in order to comply with environmental commitments in the ROD.

All areas that have been disturbed by the project were surveyed for invasive plant species occurrences post- construction. Monitoring will be conducted for five years following construction per the ROD beginning in 2017. Survey areas include Mormon Island Auxiliary Dam and haul road; sediment ponds within the Mormon Island Wetland Preserve; Left and Right Wing Dams; Dikes 1 and 4 through 8 (Figure 1). The purpose for monitoring was to provide the Central California Area Office (CCAO) with data on the location of non-native invasive species to be used in developing site and temporally specific weed control plans, as well as to evaluate the effectiveness of weed management efforts in construction-disturbed areas and adapt management strategies accordingly. Weed control recommendations are also included in this report.

Methods Prior to field surveys, maps were created outlining all areas disturbed by the project. A list of potential invasive species was developed based on the California Department of Food and Agriculture (CDFA) State Noxious Weed list and including three species specifically identified for monitoring in the ROD (i.e.

pampas grass, yellow starthistle, and French broom). Of these three species, pampas grass is the only one not on the CDFA weed list.

Surveys focused on 10 species known to be problematic in the area/region, which are listed in Table 1. The table also lists ratings as determined by the California State Noxious Weed List (CDFA 2015).

Figure 1. Project area.

Table 1. Invasive species included in surveys; Folsom Dam, CA.

Species

Species Code

State List rating1 Tree of heaven (Ailanthus altissima) AIAL C Yellow starthistle (Centaurea solstitialis) CESO C Italian thistle (Carduus pycnocephalus) CAPY C Skeleton weed (Chondrilla juncea) CHJU A Field bindweed (Convolvulus arvensis) COAR C Pampas grass (Cortaderia selloana) COSE Not Listed Stinkwort (Dittrichia graveolens) DIGR B French broom (Genista monspessulana) GEMO C Perennial pepperweed (Lepidium latifolium) LELA B Medusa head (Teaniatherum caput-medusae) TACA C

1 CDFA State Noxious Weed List A - A pest of known economic or environmental detriment and is either not known to be established in California or it is present in a limited distribution that allows for the possibility of eradication or successful containment.

B - A pest of known economic or environmental detriment and, if present in California, it is of limited distribution.

C - A pest of known economic or environmental detriment and, if present in California, it is usually widespread.

Two monitoring periods were identified per year based on timeframes that typically occur prior to the target species setting seed. The majority of species can be identified in spring surveys conducted in April; two species (stinkwort and skeleton weed) are only conspicuous later in the summer and are the focus of surveys in July (Brownsey et al. 2013, Jacobs et al. 2009). A final report follows each survey.

Field survey protocol was similar to that used for invasive plants in the Inventory Monitoring and Assessment Program, California Parks and Recreation Department (2016). Survey protocol included:

• Establishing permanent photo stations to make general observations of the site conditions and revegetation condition

• Conducting walking surveys throughout entire disturbed areas

• Using Global Positioning System (GPS) to identify locations or population perimeters

• Photographing locations of non-native invasive species occurrences

ArcGIS software was used to create maps showing all GPS locations and the aerial extent of invasive species detected in the survey.

Results Invasive plant species summer surveys were conducted July 23 to 26, 2019. At this time, the most commonly detected species were yellow starthistle and stinkwort. Yellow starthistle, which was also commonly detected in April in pre-flower stages, was found in flowering stage throughout the survey area while stinkwort was detected in pre-flower stage (Figure 2). Stinkwort has spread since previous surveys and now occupies all monitoring sites. In revegetated areas within MIAD, Haulroad, and Left Wing Dam survey sites, the species was detected in seedling form in increasing abundance (Figure 3). This species is of concern in California, where it has increased in abundance and expanded its range in recent years (Brownsey at al. 2013).

Figure 2. Yellow starthistle in flower stage (left) and stinkwort in pre-flower or stem development stage (right) within the Folsom project area.

Figure 3. Stinkwort seedlings (green plants in photo taken from above) within revegetated areas of Left Wing Dam; July 2018.

Italian thistle, which was frequently detected in April, was in the senescent or post-flower stage of development by July and was no longer present in most areas. Therefore, this species was not included in July maps. Skeleton weed was relatively common in flower stage throughout the survey area and populations appear to be on the rise. Medusahead was only detected in a few areas but was widespread in the Mormon Island sediment pond survey site and appeared to be spreading into the MIAD site across the road. Other species detected in July surveys were perennial pepperweed, tree of heaven, and field bindweed, all found in flowering or post-flowering stages and in relatively small quantities.

Approximate locations of invasive species were mapped within areas identified as being disturbed by construction activities. Maps that were produced following July 2019 surveys are included in Appendix A. The individual species and estimated total cover of all invasive species detected within each polygon were included in maps. Percent cover was estimated within ranges shown in Table 2.

Table 2. Categories used for percent total cover of invasive species.

Descriptor Percent total cover Trace < 5 % Low 5 - 50 % High 51 - 100 %

There were some large swaths where no invasive species were recorded on current maps, particularly in the Haulroad site. It was not uncommon to find individual plants of target species in these areas, however, occurrences were rare and populations too small to address with treatment. Mapping rare occurrences as “trace” across broad expanses in the disturbed areas would drastically increase the area occupied by weeds and distort the tracking of weed expansion over time.

Therefore, these incidents were not documented outside of noting them here.

The approximate number of hectares within which invasive plant species were detected is listed in Table 3. Note that hectares of invasive plant species included a few different species in April and July. Specifically, stinkwort and skeleton weed were not included in April areas and Italian thistle was not included in July areas. Invasive species were found within a higher percentage of hectares in July than in April in all years, covering roughly 30 percent of the surveyed area over the monitoring period in April and increasing from 46 percent in 2017 to 70 percent in 2019 in July surveys.

Table 4 shows an increase from July 2017 to July 2019 in the number of hectares in which the 4 dominant species were detected. Trace amounts (less than 5 percent) of all species increased considerably, indicating expansion of these species into new areas. High coverage (51 to 100 percent) of yellow starthistle increased in coverage from approximately 11.6 to 21.4 ha, indicating that areas in which this species was already detected have become more dense.

Table 3. Number of hectares within which invasive plant species were detected by site and survey period.

Site

No. of hectares with invasive plant occurrences 2017 2018 2019

April July April July April July Dike 1 0.3 0.4 0.2 0.6 0.2 0.6 Dike 4 1.1 1.3 1.0 1.2 1.1 1.5 Dike 5 4.4 4.3 2.8 2.8 3.5 3.0 Dike 6 1.9 1.7 1.4 1.6 1.1 1.6

Right Wing Dam 9.6 7.7 6.1 8.4 8.1 9.7 Left Wing Dam 11.1 11.1 7.7 14.8 8.1 24.2

Haulroad/ Dikes 7 and 8 2.1 8.1 4.9 15.1 4.4 15.9

MIAD 11.4 28.9 13.4 34.1 14.1 35.5

MIAD Sediment Pond 1.8 3.9 2.0 4.2 3.2 4.0 Total ha invasive plants 43.6 67.5 39.5 82.7 43.8 96.2

Total ha surveyed 143.1 144.5 142.7 136.9 142.7 137.4 % of Total ha Surveyed 30.5 46.4 27.7 57.4 30.2 70.0

Table 4. Hectares of invasive plant detections by species and cover class in July 2017, 2018, and 2019.

Hectares by species and cover class

Trace (0-5%)

Low (6-50%)

High (51-100%)

Total hectares by species

Yellow starthistle

July 2017 18.75 16.75 11.58 47.08 July 2018 44.52 10.27 16.60 71.39 July 2019 46.45 11.03 21.35 78.83

Stinkwort

July 2017 23.18 10.62 0.84 34.64

July 2018 39.92 9.9 2.7 52.52 July 2019 41.27 11.43 3.39 56.09

Skeletonweed

July 2017 1.61 0.30 0.00 1.91 July 2018 12.99 0.98 0.05 14.02 July 2019 17.29 0.44 0.01 17.74

Medusahead

July 2017 0.32 3.04 0.77 4.13 July 2018 0.33 5.94 0.96 7.23 July 2019 3.39 2.73 2.81 8.93

Photo stations were established within disturbance sites and locations are included in maps in Appendix A. Appendix B includes photos taken at each station in July from 2017 to 2019.

An invasive plant management plan is included in Appendix C, which addresses control of weeds detected in surveys in July 2019.

Literature Cited Brownsey, R., G.B. Kyser, and J.M. DiTomaso. 2013. Stinkwort is Rapidly

Expanding its Range in California. California Agriculture 67(2):110-115.

CDFA (California Department of Food and Agriculture). 2015. Plant Health and

Pest Prevention Services Webpage. Accessed May 6, 2016.

https://www.cdfa.ca.gov/plant/ipc/encycloweedia/winfo_weedratings.html

California Parks and Recreation. 2016. Inventory Monitoring and Assessment

Program Webpage. Accessed May 25, 2016.

http://www.parks.ca.gov/pages/734/files/imap%20invasive%20alien%20p lant%20protocol%20table%20.pdf

Jacobs, J., K. Goodwin, and D. Ogle. 2009. Plant Guide for rush skeletonweed

(Chondrilla juncea L.). USDA-Natural Resources Conservation Service, Montana State Office, Bozeman, MT 59715

O’Meara, S. 2016. Draft Integrated Pest Management Plan, Folsom Dam. USDI, Bureau of Reclamation, Central California Office, Folsom, CA.

https://www.cdfa.ca.gov/plant/ipc/encycloweedia/winfo_weedratings.html http://www.parks.ca.gov/pages/734/files/imap%20invasive%20alien%20plant%20protocol%20table%20.pdf http://www.parks.ca.gov/pages/734/files/imap%20invasive%20alien%20plant%20protocol%20table%20.pdf

Appendix A

Invasive Plants Location Maps July 2019

A-1

A-2

A-3

A-4

A-5

A-6

A-7

A-8

A-9

A-10

Appendix B

Photo Stations Summer Surveys

July 2017, 2018, and 2019

A-1

Dike 1 D1-1 downstream

July 2017 July 2018 July 2019

D1-2 downstream

Dike 4

D4-1 upstream

July 2018 July 2019

D4-1 downstream

D4-2 upstream north

D4-2 upstream south

D4-2 downstream north

D4-2 downstream south

A-3

Dike 5 D5-1 downstream

D5-1 upstream

D5-2 downstream

July 2017 July 2018

D5-2 upstream

A-4

Dike 6 D6-1 downstream

D6-1 upstream

D6-2 downstream

D6-2 upstream

July 2017 July 2018

A-5

Right Wing Dam RW north

RW south

Left Wing Dam

LW-1

LW-2

A-6

LW-3

Haulroad HR-1 east

HR-2 west

HR-3

July 2017 July 2019

A-7

Dike 7

Morman Island Auxiliary Dam

MIAD-1 east

MIAD-1 south

MIAD-2

A-8

MIAD-3 northeast

MIAD-3 southeast

Appendix C

Invasive Plant Management Recommendations

Overview Successful management of invasive weeds in disturbed areas at Folsom Dam will require regular observance of populations and growth stages, in addition to well-timed implementation of mechanical and chemical controls. The management recommendations in this appendix are based on the April and July 2019 weed surveys, which may not precisely conform to field conditions in previous or following seasons. The recommended treatments therefore should not necessarily override previous recommendations for late-season weed management, nor will they remain accurate as best recommendations in future years; real-time assessment of weed populations during treatments will provide the most efficient and effective management.

Per the existing Performance Work Statement contract for the Weed Abatement Program (WAP, 2015) for the Reclamation Central California Area Office, the following herbicides are approved for use on Reclamation lands:

• Sulfometuron-methyl (Oust®, Spyder®)

• Oxyfluorfen (Goal®)

• Glyphosate (Rodeo®, RoundUp®)

• Oryzalin (Surflan®)

• Clopyralid (Transline®, Stinger®)

• Tricloypr (Pathfinder®, Garlon®)

• Aminopyralid (Milestone®)

• Sulfentrazone (Portfolio®, Dismiss®)

All chemical application recommendations for weed control will be limited to these herbicides. Herbicide application timing should generally fall within the pre-and post-emergence timeframes stated in the WAP, summarized here:

• Pre-emergence – October to December

• Post-emergence – January to February

• Touch-up – March to May

It is recommended that post-emergent application timing be expanded in the WAP to include December through March. This modification will permit more flexibility for early and late-season germinating weeds to be treated at an optimal growth stage.

Mowing is typically conducted by staff at Folsom Dam as part of regular O&M.

The WAP states that, should the contractor fail to provide effective chemical treatment, the contractor is responsible for providing mechanical abatement to protect buildings, campgrounds, pipelines, powerhouses, water treatment plants, and all other structures or appetences – but only from a wildland fire threat. For the purposes of the management recommendations stated here it is assumed that there is no timeframe set forth that would exclude mowing either by the WAP contractor or Folsom O&M staff.

Treatments 2019 treatment recommendations consist of mowing, post-emergence and pre-emergence herbicide applications. All herbicide treatments should be band or spot applied, per the WAP and as recommended in the treatment maps included in this report. Mowing should be conducted per existing O&M protocols and/or as described in the WAP.

Recommended timings for treatments of specific areas designated in the treatment maps are presented in Table C-1. Distinction of spot and band application areas are also specified in the treatment maps. For example, areas designated in treatment maps as B-BAND should be mowed in February, applied with a banded treatment of post-emergent herbicides in March, and banded pre-emergent application of herbicides in October. Areas designated as B-SPOT would have the same timing for all management activities but with spot applications of both pre and post-emergent herbicides instead of band applications. These recommendations should not supersede treatments based on real-time observations of growth stage, soil conditions, weather, or environmental hazards.

Table C-1. Recommended timing for weed treatment zones corresponding to physical locations presented in weed treatment maps.

TREATMENT JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

MOWING ABC CD

SPRAY-POST ABC CD

SPRAY-PRE BCD

Post-emergent treatments Application of glyphosate is recommended for all post-emergent treatments through the specified time period. Areas where drift or runoff to water bodies could occur should use the Rodeo® formulation (EPA Reg. No. 62719-324).

Other areas where water contamination is not an issue should use the RoundUp® formulation (EPA Reg. No. 524-445) to provide better leaf penetration and plant uptake. All application rates should follow labeled guidelines.

Pre-emergent treatments Aminopyralid (Milestone®, EPA Reg. No. 62719-537) is recommended for all pre-emergent treatments through the specified time period. Aquatic formulations for this product are not available, and applications should not be conducted to areas where surface water is present or to intertidal areas below the mean high water mark, regardless of these recommendations. Pre-emergence herbicide applications should be band-applied; spot applications are not suitable for pre-emergent treatments. All application rates should follow labeled guidelines.

Woody species treatments Tree of heaven (Ailanthus altissima) was the only invasive woody species, detected in two polygons in the course of the current surveys. Recommended control of this species is the “hack and squirt” method: cut trees near the base and apply triclopyr to the cut stump no more than 30 minutes after the cut. Use of the aquatic registered formulation Garlon® 3A (EPA Reg. No. 62719-37) is suggested. Best timing for treatment is during active growth (June-September).

All application rates should follow labeled guidelines.

Note that woody treatments are not indicated in table C-1 nor in the treatment maps as they currently occur only in small isolated populations; see weed survey maps for tree of heaven (AIAL) locations.

C-4

C-5

C-6

C-7

C-8

C-9

C-10

C-11

C-12

C-13

C-14