salt river ecosystem restoration project final report · ecotone (year 1), final report 1 h. t....

1125 16th Street, Suite 209 Arcata, CA 95521 Ph: 707.822.4141 F: 707.822.4848

Salt River Ecosystem Restoration Project (Phase 1): Vegetation Monitoring for the

High Marsh Ecotone (Year 1)

Final Report

HTH Project# 3117-10 Ducks Unlimited Project# US-CA-478-1

Prepared for:

Humboldt County Resource Conservation District Attn: Doreen Hansen

5630 South Broadway Eureka, CA 95503

p (707) 786-9766

Prepared by:

H. T. Harvey & Associates

18 December 2014

SRERP Vegetation Monitoring for the High Marsh Ecotone (Year 1), Final Report i H. T. Harvey & Associates

18 December 2014

Executive Summary

The Salt River Ecosystem Restoration Project (SRERP) is a collaborative project designed to restore ecologic, geomorphic, and hydrologic function within the Salt River watershed and alleviate flooding problems. The Humboldt County Resource Conservation District (HCRCD) is coordinating the project. Phase 1 construction was completed in 2013. As part of the project’s habitat mitigation and monitoring plan (HMMP), a 10-year monitoring schedule was set up to determine whether the site is progressing along a trajectory that will meet projected habitat goals, with specific success criteria set as milestones for each monitoring year. The purpose of this report is to document Year 1 quantitative monitoring for one habitat component: the high marsh ecotone. This transitional habitat was created to provide a gradual slope from restored tidal wetlands to a new setback levee that was created to protect adjacent agricultural lands from tidal inundation. Year 1 quantitative monitoring of the SRERP Phase 1 high marsh ecotone involved: 1) habitat mapping to determine habitat acreage; and 2) percent cover assessment to determine plant species composition and percent cover. Overall, high marsh ecotone habitat mapped for Year 1 was calculated to comprise 17.6 acres (ac), which is 47% greater than the projected habitat acreage of 12.0 ac. Cover by native plant species in the high marsh ecotone was 24.1%, significantly greater than the minimum 5% cover set as a Year 1 success criterion for this habitat type. This was largely due to the successful establishment of two native grasses, tufted hairgrass and meadow barley, both of which were components of the hydroseed mix applied as part of the restoration effort. Additionally, it is encouraging that natural recruitment by a number of native marsh species was observed in the created high marsh ecotone habitat. Adjacent restored salt marsh habitat has its own set of milestone success criteria to meet for minimum native plant cover, not addressed at this time. Quantitative monitoring for salt marsh will be initiated in Year 3. The Year 10 success criterion for both salt marsh and high marsh ecotone is a minimum of 60% native plant cover. Cover by invasive plant species and cover by non-native non-invasive plant species occurring in the high marsh ecotone were also assessed as part of this monitoring effort; however no milestone success criteria were specified by the HMMP. The Year 10 success criterion for all tidal wetland habitats (comprising over 300 ac of salt marsh in addition to the high marsh ecotone) is a maximum of 5% cover by invasive plant species and 15% by non-native non-invasive plant species. Evaluation of this criterion will require more comprehensive monitoring of all SRERP tidal wetland habitats as the project progresses. Nonetheless, it is not too early to consider what management actions are appropriate to move the project towards Year 10 goals. In the high marsh ecotone, Year 1 total cover by invasive plant species was 1.1%. Invasive Spartina (Spartina densiflora) was detected in high marsh ecotone sampling, and also was observed occurring within the adjacent restored tidal marsh. The presence of invasive Spartina is a trigger for control actions. In fall 2014, HCRCD initiated Spartina removal in restored salt marsh (Hansen, pers.comm.) Spartina control in the high marsh ecotone is also needed. Total cover by non-native non-invasive plants in the high marsh ecotone was 18.5%. Most of this cover is attributable to fat-hen (Atriplex prostrata), an early seral plant that may decline

SRERP Vegetation Monitoring for the High Marsh Ecotone (Year 1), Final Report ii H. T. Harvey & Associates

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over time as other species become established. Control actions for fat-hen are not considered warrantable at this time, nor is it expected that control will be needed in the future. Continued monitoring as scheduled for all other invasive and non-native plant species is considered sufficient management action at this time. The establishment of desirable high marsh ecotone vegetation throughout all target regions and elevation ranges is considered an indication of success for this habitat type at this time. The results presented here should be considered in the larger context of restoration of the Salt River estuary ecosystem.

SRERP Vegetation Monitoring for the High Marsh Ecotone (Year 1), Final Report iii H. T. Harvey & Associates

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Table of Contents

Executive Summary ............................................................................................................................................................. i

Table of Contents .............................................................................................................................................................. iii Section 1.0 Introduction .................................................................................................................................................... 1

1.1 Project Background ................................................................................................................................................. 1 1.2 Project Purpose ........................................................................................................................................................ 1

Section 2.0 Methods ........................................................................................................................................................... 3 2.1 Habitat Mapping ...................................................................................................................................................... 3 2.2 Percent Cover Assessment ..................................................................................................................................... 3

2.2.1 Field Sampling.................................................................................................................................................. 3 2.2.2 Plant Species Categorization .......................................................................................................................... 6 2.2.3 Data Analysis.................................................................................................................................................... 7

Section 3.0 Results .............................................................................................................................................................. 9 3.1 Habitat Mapping ...................................................................................................................................................... 9

3.1.1 Habitat Map...................................................................................................................................................... 9 3.1.2 Habitat Acreage Success Criterion ............................................................................................................... 9

3.2 Percent Cover Assessment ................................................................................................................................... 12 3.2.1 Plant Species Composition .......................................................................................................................... 12 3.2.2 Percent Cover Success Criteria ................................................................................................................... 18

Section 4.0 Discussion ..................................................................................................................................................... 20 4.1 Success Criteria ...................................................................................................................................................... 20

4.1.1 Habitat Acreage Success Criterion ............................................................................................................. 20 4.1.2 Percent Cover Success Criteria ................................................................................................................... 21

4.2 Management Recommendations ......................................................................................................................... 22 4.3 Future Monitoring ................................................................................................................................................. 22

Section 5.0 References ..................................................................................................................................................... 23 Tables Table 1. Strata Used for Spatial Distribution of Sample Plots, Based on Geography and Elevation ............. 4 Table 2. Modified Braun-Blanquet (1928) Plant Cover-Abundance Scale........................................................... 4 Table 3. California Invasive Plant Council (Cal-IPC 2014) Ratings and Definitions ......................................... 6 Table 4. Percent Cover and Frequency of Ground Cover Components ........................................................... 12 Table 5. Plant Species Composition in the High Marsh Ecotone, Year 1 ......................................................... 13 Table 6. Native Plant Species Establishment from Hydroseed and Natural Recruitment .............................. 15 Table 7. Suggested Categorization of Non-native Plant Species as Invasive or Non-invasive....................... 17 Table 8. Percent Cover Assessment for the High Marsh Ecotone, Year 1 ....................................................... 19 Figures Figure 1. Salt River Vicinity Map ................................................................................................................................. 2 Figure 2. Sample Plot Layout ........................................................................................................................................ 5 Figure 3. Projected High Marsh Ecotone Habitat................................................................................................... 10 Figure 4. Year 1 High Marsh Ecotone Habitat ........................................................................................................ 11

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Photos Photo A. Sample Plot Quadrat Used for Assessing Plant Cover ............................................................................ 4 Photo B. Mixture of Native Grasses and Sterile Wheat in Ecotone Area with High Total Vegetation

Cover .............................................................................................................................................................. 15 Photo C. Natural Recruitment by Perennial Pickleweed (Salicornia pacifica)......................................................... 16

List of Preparers Annie Eicher, M.A. Senior Ecologist/Plant Ecology Daniel Stephens, B.S. Principal/Restoration Ecology Maximiliano Busnardo, M.S. Sr. Restoration Ecologist Ken Lindke, M.S. Junior Quantitative Ecologist/Wildlife Biology

SRERP Vegetation Monitoring for the High Marsh Ecotone (Year 1), Final Report 1 H. T. Harvey & Associates

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Section 1.0 Introduction

1.1 Project Background

The Salt River Ecosystem Restoration Project (SRERP) is a collaborative project designed to restore ecologic, geomorphic, and hydrologic function within the Salt River watershed and alleviate flooding problems. The project was needed because hydraulic function of the Salt River had been severely impaired by channel alteration and heavy siltation. SRERP is located in coastal Humboldt County in northern California (Figure 1). The Salt River is a tributary of the lower Eel River. The Humboldt County Resource Conservation District (HCRCD) is coordinating project efforts to restore 7.7 miles (mi) of the Salt River channel and over 800 acres (ac) of adjacent land over multiple years. SRERP Phase 1 included excavating and widening the lower 2.5 mi of the Salt River channel, re-stablishing tidal connectivity to over 300 ac of pasture lands that were historically tidal marsh, and restoring about 40 ac of riparian forest/scrub habitat. The Phase 1 agricultural parcel, also known as Riverside Ranch, is now under ownership of the California Department of Fish and Wildlife. As part of SRERP Phase 1 implementation, a new two-mile setback levee was constructed to protect adjacent agricultural lands from tidal inundation. The tidal side of the levee was designed with a gradual slope to create a natural transition zone from wetland to upland. This transitional habitat, referred to as the high marsh ecotone, was projected to comprise 12 ac between 7.5–9 feet (ft) (all elevations in report are NAVD88 datum). The high marsh ecotone area was created by placing fill material derived on-site and contouring the slope. The ecotone was hydroseeded in September–October 2013 (GHD 2014). The purpose of seeding was to prevent erosion and encourage establishment by native plant species. Available native plant species appropriate for this habitat type were used in the seed mix. In addition, a sterile hybrid wheatgrass (Elymus X Triticum) was included in the seed mix to help achieve high cover the first year. Since this plant is a sterile annual, it will not persist in subsequent years. In October 2013, tidal inundation was restored to the Salt River estuary and the newly created tidal marsh area, with the highest tides inundating the high marsh ecotone.

1.2 Project Purpose

In September 2014, H. T. Harvey & Associates (HTH) conducted quantitative habitat monitoring for high marsh ecotone habitat the first growing season (Year 1) following re-introduction of tidal inundation. The monitoring was conducted in response to a request from the HCRCD to assist them with fulfilling this task of the project monitoring requirements. The monitoring was performed in accordance with the Salt River Ecosystem Restoration Project Habitat Mitigation and Monitoring Plan (HMMP) (HTH and Winzler & Kelly 2012). The HMMP established a 10-year monitoring schedule to determine whether the site is progressing along a trajectory that will meet projected habitat goals, with specific success criteria set as milestones for each monitoring year. The schedule included quantitative monitoring of high marsh ecotone habitat in Years 1, 2, 3, 5, 7, and 10.

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Figure 1: Salt River Vicinity Map

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Salt River Ecosystem Restoration Project Vegetation Monitoring for the High Marsh Ecotone (Year 1) (3117-10)

H u m b o l d t B a y

PACIFICOCEAN

Eureka

H U M B O L D T

T R I N I T Y

S I S K I Y O U

M E N D O C I N O

D E L N O R T E

S H A S TA

Project Vicinity

Detail

California

PACIFICOCEAN

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Miles

LegendSalt River Ecosystem RestorationProject (SRERP)SRERP Phase 1 Boundary


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Section 2.0 Methods

Vegetation data collection, assessment, and mapping were conducted by HTH Senior Plant Ecologist Annie Eicher, with support from HTH GIS Specialist staff. Statistical analysis was performed by HTH Quantitative Ecologist Ken Lindke, with oversight by HTH Senior Restoration Ecologist Max Busnardo. Project oversight was provided by HTH Principal Restoration Ecologist Dan Stephens. Annie Eicher attended a reconnaissance site visit with HCRCD Watershed Coordinator Doreen Hansen on 5 September 2014, and conducted field sampling on 23 September 2014. HTH ecologists conducted the monitoring in accordance with the project’s HMMP. The methods employed are summarized below.

2.1 Habitat Mapping

HTH prepared a map depicting the current extent of high marsh ecotone habitat at SRERP Phase 1 based on a combination of aerial photointerpretation, ground-truthing, and projections based on elevation range for this habitat type. We used existing post-construction satellite imagery (Google Earth 28 May 2014) and Geographic Information Systems (GIS) software for both field mapping and preparation of the map. Based on the restoration design, it was projected that high marsh ecotone habitat would occupy elevations between 7.5–9 ft (HTH and Winzler & Kelly 2012). The existing map showing the projection for high marsh ecotone habitat was used as a reference, and as-built topographic contours provided guidance for revising the map to depict current conditions. HCRCD provided 1-ft contours of the as-built condition, in GIS format (converted from AutoCAD). Based on restoration projections and supported by site observations on 5 September 2014, we used an interpolated 7.5 ft contour line as the estimate for the lower boundary and the 9.0 ft contour line for the upper boundary of the high marsh ecotone habitat to produce a draft map. The draft map was ground-truthed during the 23 September 2014 site visit. Acreage of the current extent of high marsh ecotone habitat was then calculated using GIS software.

2.2 Percent Cover Assessment

2.2.1 Field Sampling

Percent cover data were collected using plot-based field sampling methods. Plots were placed in a spatially stratified random manner within geographic and elevational strata. Stratification was used to ensure that plots were distributed over the sample frame (i.e., sampling boundary) in a representative and un-biased manner. It was not a purpose of this stratification to analyze potential differences in vegetation among the strata. We used two geographic strata and two elevational strata, resulting in four sample strata. HCRCD recognizes North and South sections of SRERP Phase 1, divided by an access road at the approximate center of the site, so we used this division to create the two geographic strata. For elevational strata, we used high and low zones, separated by an interpolated 8.25 ft contour line. We then generated 100 random sample points using GIS software. The points were spatially distributed among the four sample polygons in the same ratio as


18 December 2014

surface area, with the points set to occur a minimum distance of 32.8 ft (10 meter [m]) apart from one another (Table 1, Figure 2). Table 1. Strata Used for Spatial Distribution of Sample Plots, Based on Geography and Elevation

Stratum Name Elevation Range (ft NAVD88) Number of Sample Plots (n)

North High 8.25–9.0 13

North Low 7.5–8.25 11

South High 8.25–9.0 42

South Low 7.5–8.25 34

Total 100

Sample plots were 10.8 ft2 (1 m2 ) square quadrats (Photo A). Within each plot, all plant species present were recorded and the percent cover by species was visually estimated within cover classes using a modified Braun-Blanquet (1928) cover-abundance scale (Table 2). Additionally, visual estimates were made for total vegetation cover and cover by the plant litter layer, bare ground, and algae to the nearest 5% cover and to the nearest 1% for occurrences having < 5% cover. Taxonomic nomenclature used herein follows Baldwin et al. (2012), and common names used in the text of this report follow Calflora (2014).

Table 2. Modified Braun-Blanquet (1928) Plant Cover-Abundance Scale

Cover Class Range of Percent Cover Median (%)

r < 1 (single individual) 0.1

+ < 1 (sproadic or few) 0.5

1 1–5 3.0

2 >5–25 15.0

3 >25–50 37.5

4 >50–75 62.5

5 >75–95 85.5

6 >95-100 97.5

Photo A. Sample Plot Quadrat Used for Assessing Plant Cover

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LegendSRERP Phase1 Boundary

Contour7.5' NAVD 888.25' NAVD 889' NAVD 88North High Sample PointsNorth Low Sample PointsSouth High Sample PointsSouth Low Sample Points

Salt River Ecosystem Salt River Ecosystem Restoration Project Phase 1Restoration Project Phase 1

Image: Google Earth 28 May 2014


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2.2.2 Plant Species Categorization

All plant species encountered in sample plots were categorized as either native, non-native non-invasive, or invasive. The purpose of the categorization was to serve as a basis of comparison of current site conditions with the HMMP’s success criteria for minimum cover by native plants and maximum cover by non-native non-invasive plants and by invasive plants. Native plants are defined as plants that are believed to occur in the region naturally. Non-native plants have been introduced either as a direct or indirect result of human activity. Invasive plants are defined by the California Invasive Plant Council (Cal-IPC) as non-native plants that threaten wildlands by displacing native species, hybridizing with native species, altering biological communities, or altering ecosystem processes (Cal-IPC 2014). Cal-IPC maintains an online database called The California Invasive Plant Inventory with ratings for non-native invasive plants that threaten the state's wildlands (Cal-IPC 2014). Cal-IPC ratings represent the best available knowledge of invasive plant experts in the state. The Cal-IPC evaluation considers cumulative statewide impacts of each plant based on an assessment of the plant’s ecological impacts, invasive potential, and ecological amplitude and distribution (Table 3). Table 3. California Invasive Plant Council (Cal-IPC 2014) Ratings and Definitions

Cal-IPC Rating Definition

High These species have severe ecological impacts on physical processes, plant and animal communities, and vegetation structure. Their reproductive biology and other attributes are conducive to moderate to high rates of dispersal and establishment. Most are widely distributed ecologically.

Moderate These species have substantial and apparent—but generally not severe—ecological impacts on physical processes, plant and animal communities, and vegetation structure. Their reproductive biology and other attributes are conducive to moderate to high rates of dispersal, though establishment is generally dependent upon ecological disturbance. Ecological amplitude and distribution may range from limited to widespread.

Limited These species are invasive but their ecological impacts are minor on a statewide level or there was not enough information to justify a higher score. Their reproductive biology and other attributes result in low to moderate rates of invasiveness. Ecological amplitude and distribution are generally limited, but these species may be locally persistent and problematic.

For the current assessment, all plants having Cal-IPC ratings of “High” or “Moderate” were categorized as invasive. Cal-IPC recognizes that the impact of invasive plants in specific geographic regions or habitats within California may be greater or lesser than their statewide rating indicates, and suggests that management actions for a species should be considered on a local and site-specific basis. Therefore, plants having a Cal-IPC rating of “Limited” were categorized as either invasive or non-native non-invasive based on available information on the ecological impacts and/or level of threat to wildlands locally. The Humboldt County Weed Management Area (2010) rated weeds in terms of strategic priority for management, and these ratings were taken into consideration. Other sources consulted containing information on local levels of invasiveness


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were Leppig and Pickart (2013) and Pickart (2006). The categories suggested for the current assessment were made in consultation with Andrea Pickart (Ecologist, Humboldt Bay National Wildlife Refuge) on 16 October 2014 (Pickart pers. comm.).

2.2.3 Data Analysis

Following the 23 September 2014 sampling, we performed a preliminary data assessment to determine whether the sample size of the initial data collection was sufficient. We examined the data using a power analysis to determine whether there was sufficient statistical power, defined as 80% power to detect a significant difference in cover between the observed state and the Year 1 high marsh ecotone success criterion, at an 80% confidence level. First, observations of total percent cover for each plot were arcsine-square root transformed, and power analysis was conducted on these transformed values. This type of data transformation results in values that are on a continuous unbounded scale, and may give a closer approximation to normality, a key assumption for the power analysis. The equation used for the power analysis (Elzinga et al. 1998) is:

n = 2(s)2(Zα + Zβ)2

(MDC)2

Where:

s = sample standard deviation of the transformed values Zα = Z-coefficient for the false-change (Type I) error rate Zβ = Z-coefficient for the missed-change (Type II) error rate MDC = Minimum detectable change size

Further information on methods for power analysis is described in Elzinga et al. (1998). Based on the power analysis results, the initial data collection of 100 sample points was determined to be sufficient, so no further data was collected. To assess plant species composition, the median percent cover by cover class (Table 2) was used to calculate mean percent cover for each plant species observed. For each plot, total cover by native plant species was calculated as the sum of the percent plant cover for each native species observed in the plot. Mean percent cover by native plants for the survey area was then calculated as the mean of total native plant cover for all plots. Non-parametric bootstrap methods were used to construct approximate 95% confidence intervals for the mean percent cover by native plants in the survey area. Non-parametric methods were used because the data are not normally distributed. Traditional parametric methods assume that mean values are normally distributed and use student’s t distribution to give symmetric intervals. Percent cover data are inherently bounded by zero and 1 (when expressed as a proportion), whereas the normal distribution is unbounded, and correct confidence intervals are often asymmetric except when mean values of percent cover are near 50%.


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Using non-parametric bootstrap methods, the sampling error can be quantified by resampling the observed data many times, thus providing a method for constructing confidence intervals. Total percent cover values of native plant species for individual plots were resampled with replacement 100 times, and the mean of these 100 new sample values was calculated. This was repeated 1000 times to yield 1000 bootstrap replicates of mean percent cover of native species for the SRERP Phase 1 high marsh ecotone. The 95% confidence limits were defined as the 2.5th and 97.5th percentiles of these 1000 bootstrap replicates. Total cover by non-native non-invasive species and by invasive species was assessed in the same manner.


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Section 3.0 Results

3.1 Habitat Mapping

3.1.1 Habitat Map

The projection for high marsh ecotone habitat created as part of SRERP Phase 1 restoration is shown in Figure 3 and the area mapped as high marsh ecotone habitat during Year 1 monitoring is shown in Figure 4. The high marsh ecotone occurs as a linear band on the tidal side of the new setback levee. The high marsh ecotone is a transitional habitat that is inherently separate yet contiguous with both the tidal marsh and the terrestrial upland habitat on the levee. The first growing season following the re-introduction of tidal inundation, some degree of vegetation zonation is apparent though not yet well-defined enough to use as a primary basis for mapping the boundaries of the high marsh ecotone. The lower boundary of the ecotone appears generally consistent with the 7.5 ft contour line and the upper boundary with the 9.0 ft contour line, so these contours were used as the primary basis for mapping, with minor revisions made in the field based on site observations. For much of its length, the width of the ecotone averages about 45–50 ft, having a slope of about 30:1 (Horizontal (H):Vertical (V)) from levee to marsh. At the south end of the Phase 1 project area, the high marsh ecotone is much broader, extending out to widths of 250–350 ft, with slopes of 160H:1V to 230H:1V.

3.1.2 Habitat Acreage Success Criterion

Overall, high marsh ecotone habitat mapped for Year 1 was calculated to comprise 17.6 ac, which is 47% greater than the projected habitat acreage of 12.0 ac. This discrepancy is attributable to the broadly sloped area between 7.5–9 ft at the south end of the Phase 1 project area (Figure 3 and 4).


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Figure 3: Projected High Marsh Ecotone Habitat

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LegendSRERP Phase1 BoundaryProjected High Marsh EcotoneHabitat (12.38 ac)




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Figure 4: Year 1 High Marsh Ecotone Habitat

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LegendSRERP Phase1 BoundaryHigh Marsh Ecotone (17.57 ac)




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3.2 Percent Cover Assessment

3.2.1 Plant Species Composition

Total vegetation cover in the SRERP Phase 1 high marsh ecotone averaged approximately 50% based on visual estimates of cover in sample plots (n=100) sampled 23 September 2014 (Table 4). Almost all sample plots (96%) had some vegetation cover, and in plots with vegetation the cover values ranged from 1–100%. Plant litter occurred frequently (77%) with cover as high as 95%. Sampling conducted earlier in the growing season would likely have yielded results with higher live vegetation cover and lower levels of plant litter. Algal mats, indicative of wet conditions, occurred in only a few sample plots (all occurring in the North Low sample stratum), with high cover (80%) in one plot. Table 4. Percent Cover and Frequency of Ground Cover Components

Ground Cover Percent Cover (n=100) Percent Frequency

(n=100) Mean Minimum Maximum

Vegetation Cover 47.8 1 100 96

Plant Litter 22.3 5 95 77

Algae 1.1 5 80 3

Bare Ground 28.8 1 100 82

Total 100.0 Plant species composition for the high marsh ecotone is shown in Table 5. For individual plots, the sum of median cover class values may differ from the visual estimate of total vegetation cover; however, the sum of the median values for all plots (46.5%) is very close to the mean of the estimated total vegetation cover (47.8%) (Tables 4 and 5). Percent frequency calculations shown in Table 5 provide an indication of how often each plant species occurred in sample plots. For the plots in which each plant species occurred, the range of percent cover values is shown as minimum and maximum, again based on median cover class values. Some annual plant species may have been missed because the sampling was conducted late in the growing season. Additionally, cover values and/or frequency for plants observed may have been higher earlier in the growing season.

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Table 5. Plant Species Composition in the High Marsh Ecotone, Year 1

Scientific Name Common Name Native Status1

Percent Cover (n=100) Percent Frequency (n=100) Mean Minimum Maximum

Agrostis stolonifera creeping bentgrass INV 0.2 0.1 3.0 20

Anthemis cotula dog fennel NN 0.1 0.1 3.0 6

Atriplex prostrata fat-hen NN 16.2 0.1 97.5 79

Bolboschoenus maritimus subsp. paludosus alkali bulrush N 0.1 3.0 3.0 2

Cotula coronopifolia brass buttons NN 0.9 0.1 37.5 11

Cynosurus cristatus crested dogtail NN < 0.1 0.1 0.5 6

Deschampsia cespitosa tufted hairgrass N 9.4 0.1 37.5 68

Distichlis spicata saltgrass N < 0.1 0.5 0.5 1

Elymus glaucus blue wildrye N 0.3 0.1 15.0 6

Elymus X Triticum sterile hybrid wheatgrass N/A 2.8 0.1 37.5 45

Festuca perennis Italian ryegrass INV 0.3 0.1 3.0 18

Grindelia stricta gumplant N < 0.1 0.1 0.5 5

Helminthotheca echioides bristly ox-tongue INV < 0.1 0.5 0.5 1

Holcus lanatus velvet grass INV < 0.1 0.1 0.5 3

Hordeum brachyantherum meadow barley N 9.7 0.1 62.5 67

Hordeum marinum subsp. gussoneanum Mediterranean barley INV < 0.1 0.5 0.5 3

Jaumea carnosa marsh jaumea N < 0.1 3.0 3.0 1

Limonium californicum California sea lavender N < 0.1 0.1 0.1 1

Lotus corniculatus birdsfoot trefoil INV 0.1 0.1 3.0 7

Plantago lanceolata English plantain NN < 0.1 0.1 0.5 3

Polygonum aviculare prostrate knotweed NN < 0.1 0.5 0.5 1

Polypogon monspeliensis rabbitsfoot grass INV 0.3 0.1 3.0 26

Potentillla anserina subsp. pacifica Pacific silverweed N < 0.1 0.1 0.1 1

Raphanus sativus wild radish NN 0.3 0.5 15.0 4

14

Scientific Name Common Name Native Status1

Percent Cover (n=100) Percent Frequency (n=100) Mean Minimum Maximum

Rumex conglomeratus clustered dock NN < 0.1 0.5 0.5 1

Rumex crispus curly dock INV < 0.1 3.0 3.0 1

Rumex sp. dock N/A < 0.1 0.1 0.1 1

Salicornia pacifica perennial pickleweed N 3.8 0.1 62.5 29

Spartina densiflora dense-flowered cordgrass IN 0.1 0.1 3.0 6

Spergularia marina sand spurry N 0.8 0.1 15.0 22

Trifolium fragiferum strawberry clover NN 0.9 3.0 85.5 2

Trifolium pratense red clover NN < 0.1 0.5 3.0 2

Trifolium repens white clover NN 0.1 0.1 3.0 3

Total 46.5 1 N = Native; NN = Non-native non-invasive; INV = Invasive; N/A = Not Applicable. See Table 6 and 7 for more information.


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The first growing season following construction, vegetation in the high marsh ecotone is a mixture of plants that were seeded and plants that colonized by natural recruitment. The sterile hybrid wheatgrass that was hydroseeded was present in nearly half the plots with relatively low cover (2.8%). Two of the hydroseeded native grasses, tufted hairgrass (Deschampsia cespitosa) and meadow barley (Hordeum brachyantherum), each had nearly 70% frequency and 10% mean cover (Photo B). Other hydroseeded species occurring with lower abundance were blue wildrye (Elymus glaucus) and gumplant (Grindelia stricta) (Table 5). It is possible that natural recruitment also contributed to the cover observed for all the native species listed above (Table 6). Table 6. Native Plant Species Establishment from Hydroseed and Natural Recruitment

Native Plant Species Hydroseeded Natural Recruitment Regional Notes for Species

Bolboschoenus maritimus subsp. paludosus

x common in regional brackish marshes

Deschampsia cespitosa x likely common in regional brackish and salt marshes

Distichlis spicata x dominant species in regional salt marshes

Elymus glaucus x possibly occasional at upper marsh margins and agricultural wetlands

Grindelia stricta x possibly common in regional salt marshes

Hordeum brachyantherum x possibly occasional in regional brackish marshes

Jaumea carnosa x common in regional salt marshes

Limonium californicum x common in regional salt marshes

Potentillla anserina subsp. pacifica

x common in regional fresh and brackish marshes

Salicornia pacifica x dominant in regional salt marshes

Spergularia marina x colonizer in regional salt marshes

Photo B. Mixture of Native Grasses and Sterile Wheat in Ecotone Area with High Total Vegetation Cover


18 December 2014

Natural recruitment by several additional native species was evident. Perennial pickleweed (Salicornia pacifica), occurred in nearly one-third of plots, with up to 62.5% cover and an overall mean cover of 3.8% (Photo C). Salt marsh sand spurry (Spergularia marina) occurred in about one-quarter of plots with low cover. Other naturally recruiting native species occurring with lower abundance were alkali bulrush (Bolboschoenus maritimus subsp. paludosus), saltgrass (Distichlis spicata), marsh jaumea (Jaumea carnosa), California sea lavender (Limonium californicum), and Pacific silverweed (Potentilla anserina subsp. pacifica) (Tables 5 and 6).

Colonization of the ecotone by non-native plants was also evident. Non-native plants occurring in high marsh ecotone sample plots were categorized as either invasive or non-native non-invasive (Table 7). Statewide Cal-IPC ratings and Humboldt County Weed Management Area (HWMA) ratings for non-native plants occurring in the high marsh ecotone are shown in Table 7. Also shown in Table 7 are relevant notes on regional distribution, impacts, and/or threat level. None of the plants are listed as federal noxious weeds (USDA 2014). One plant species, dense-flowered cordgrass (Spartina densiflora) (commonly referred to regionally simply as Spartina), is rated as a noxious weed by the California Department of Food and Agriculture (CDFA 2014). This invasive cordgrass was inadvertently introduced to the region in the 1870s, and it has become a dominant species in the region’s salt marshes. It adversely impacts native salt marsh communities by displacing native plant species and physically altering wildlife habitat (HTH 2013). Occasional, small Spartina plants also occurred in the high marsh ecotone, with low cover (0.1%) and frequency (6%) (Table 5). Additionally, large established clumps of Spartina were observed occurring in some restored salt marsh areas. The presence of invasive Spartina is a trigger for control actions, which are discussed in more detail in the “Discussion” section of this report. None of the plant species categorized as invasive have ≥ 1% cover in the high marsh ecotone at this time. Three invasive grasses occurred with moderate frequency, including creeping bentgrass (Agrostis stolonifera), Italian ryegrass (Festuca perennis, synonyms: Lolium perenne and L. multiflorum), and rabbitsfoot grass (Polypogon monspeliensis) (Tables 5 and 7). The one of most concern is creeping bentgrass, a perennial that has aggressively invaded brackish diked wetlands regionally, altering physical characteristics and displacing native plant species (Pickart 2006). The level of threat to the high marsh ecotone is unclear, as salinity may be a factor in limiting its spread. There is little evidence of invasion by creeping bentgrass into tidal salt marsh. In a study of diked wetlands, it exhibited a significant negative correlation with conductivity, though it was observed colonizing disturbed areas with high salinity (Pickart 2006).

Photo C. Natural Recruitment by Perennial Pickleweed (Salicornia pacifica)


18 December 2014

Table 7. Suggested Categorization of Non-native Plant Species as Invasive or Non-invasive

Non-Native Plant Species

Invasive Status

Regional Notes for Species Suggested Category1

Cal-IPC Rating2

HWMA Rating3

Agrostis stolonifera invasive limited high highly invasive in brackish marshes and agricultural wetlands

Anthemis cotula non-inv not listed not listed associated with persistent disturbance

Atriplex prostrata non-inv not listed moderate colonizer of disturbed saline marshes

Cotula coronopifolia non-inv limited not listed colonizer of disturbed saline marshes

Cynosurus cristatus non-inv not listed not listed not common

Festuca perennis invasive moderate not listed commonly planted as a pasture grass; not aggressive in wildlands

Helminotheca echioides invasive limited not listed can form dense stands in coastal areas

Holcus lanatus invasive moderate moderate invasive in fresh to brackish marshes and agricultural wetlands

Hordeum marinum invasive moderate not listed associated with persistent disturbance

Lotus corniculatus invasive not listed monitor invasive in fresh to brackish marshes and agricultural wetlands; persistent seedbank stimulated by disturbance

Plantago lanceolata non-inv limited not listed associated with persistent disturbance

Polygonum aviculare non-inv not listed not listed not known to be invasive

Polypogon monspeliensis invasive limited monitor common in disturbed areas at upper marsh margins

Raphanus sativus non-inv limited not listed associated with persistent disturbance

Rumex conglomeratus non-inv not listed not listed occurs in fresh to brackish marshes and agricultural wetlands, usually with low abundance

Rumex crispus invasive limited not listed can form dense stands

Spartina densiflora4 invasive high high highly invasive in salt marshes; target of regional eradication program; top priority control concern for SRERP tidal marsh and ecotone

Trifolium fragiferum non-inv not listed not listed commonly planted for forage

Trifolium pratense non-inv not listed not listed commonly planted for forage

Trifolium repens non-inv not listed not listed commonly planted for forage 1 Suggested categories for non-native plants: Invasive and Non-invasive (non-inv) 2 California Invasive Plant Council (Cal-IPC 2014) statewide ratings for invasive weeds 3 Humboldt County Weed Management Area (HWMA 2010) county ratings for invasive weeds 4 Spartina densiflora is listed as a noxious weed by the California Department of Food and Agriculture

(CDFA 2014)


18 December 2014

Italian ryegrass is a commonly planted pasture grass in Eel River floodplain lowlands, and it was approved for including in seed mixes for agricultural lands disturbed as part of SRERP actions. The risk of invasion into adjacent tidal wetlands is considered relatively low. Cal-IPC rates ryegrass as a moderate threat, mostly to grassland communities, noting that most seed probably falls close to parent plant and that human activities are the main vector of dispersal (DiTomaso 2003). Pickart (2006) found that Italian ryegrass was mostly confined to the hayed/grazed pastures at the Humboldt Bay National Wildlife Refuge. Rabbitsfoot grass is an annual grass that is most often associated with disturbed conditions. It occurred in about one quarter of sample plots with relatively low cover (Table 5). This grass may decline in the absence of ongoing disturbance. Fat-hen (Atriplex prostrata) was categorized as non-native non-invasive for purposes of this assessment. This annual herb is noteworthy because it was a dominant species in the high marsh ecotone (Table 5). Fat-hen was included in early proposed seed mixes for SRERP, and later dropped. There has been some confusion regarding the taxonomy and native status of this plant. The plant was at one time considered native to our region, with the scientific name Atriplex patula ssp. hastata, now considered a mis-applied name (Baldwin et al. 2012). A related plant, spear orache (Atriplex patula) is currently listed by Baldwin et al. (2012) as a native species, but with a footnote that it is possibly naturalized. Spear orache occurs in regional tidal marshes (Leppig and Pickart 2013); however it is uncommon. Fat-hen is common throughout our region, occurring in and adjacent to high tidal marshes. Locations where the plant is abundant are typically associated with disturbance. Sawyer et al. (2009) characterizes fat-hen as an early seral plant and fat-hen dominated vegetation as an ephemeral marsh type associated with seasonally flooded conditions and relatively high salinities. The presence of fat-hen in the SRERP Phase 1 high marsh ecotone may decline as other plant species become established. Another early seral plant commonly associated with fat-hen is brass buttons (Cotula coronopifolia), which had almost 1% cover and a 11% frequency in the high marsh ecotone. None of the other non-native non-invasive species had ≥ 1% cover or moderate to high frequency in the ecotone (Tables 5 and 7).

3.2.2 Percent Cover Success Criteria

The mean cover by native plant species in the high marsh ecotone was estimated to be 24.1% (Table 8) and exceeds the Year-1 success criterion of 5% cover. The results of our power analysis indicated that we had a sufficiently robust sampling level to determine that this cover estimate is significantly greater than the minimum 5% cover set as a Year 1 success criterion. Additionally, 95% confidence limits shown in Table 8 provide a measure of how reliable the estimated mean cover value is based on the variance in the data; the lower bounds of the 95% confidence interval is greater than the Year-1 success criterion (5%). The two species with the highest cover were meadow barley (9.7%) and tufted hairgrass (9.4%), both components of the hydroseed mix. Natural recruitment by the halophyte perennial pickleweed contributed 3.8% cover. The other eight native plant species occurring in sample plots each had < 1% cover (Table 4).


18 December 2014

Table 8. Percent Cover Assessment for the High Marsh Ecotone, Year 1

Plant Species Category Mean Percent Cover (n=100)

95% Confidence Intervals

Lower Limit Upper Limit

Native species 24.1 19.7 28.4

Non-native non-invasive species 18.5 13.6 24.1

Invasive species 1.1 0.7 1.5

Sterile hybrid wheatgrass 2.8 N/A N/A

Total 46.5

A maximum of 5% cover by invasive plant species and a maximum of 15% cover by non-native non-invasive plant species by Year 10 have been set as success criteria for restored tidal wetland habitats (comprising over 300 ac of salt marsh in addition to the high marsh ecotone) (HTH and Winzler & Kelly 2012). In Year 1, the mean cover by non-native non-invasive plant species in the high marsh ecotone was 18.5% (Table 8). Most of this cover was attributable to fat-hen (16.2%), occurring in 79% plots, with up to 97.5% cover and an overall mean cover of 16.2%. The other 10 non-native non-invasive plant species each had < 1% cover (Tables 4 and 5). The mean cover by invasive plant species was 1.1% (Table 8). No single invasive species had ≥ 1% cover (Tables 4 and 5).


18 December 2014

Section 4.0 Discussion

The SRERP HMMP set success criteria for each habitat type for each monitoring year (HTH and Winzler & Kelly 2012). This report addresses Year 1 success criteria for the SRERP high marsh ecotone. It is important to keep in perspective that this represents an early look at a relatively small portion of a much larger long-term restoration project. The results presented here should be considered in the larger context of restoration of the Salt River estuary ecosystem. Evaluation of other restored habitats is beyond the scope of this monitoring effort; however, references to the adjacent newly restored tidal marsh are included in this discussion as a necessary component for evaluating the high marsh ecotone. The creation of high marsh ecotone habitat along the tidal side of the new setback berm provided a beneficial use for fill material generated during the process of restoring the Salt River estuary. The ecological value of creating and maintaining transitional habitats in tidal marsh restoration projects is receiving increased recognition (Collins and Grossinger 2004, Baye 2008). The high marsh ecotone habitat created has the potential to provide a buffer zone for the restored tidal marsh, high tide flood refuge habitat for marsh wildlife, and provides some area above Mean Higher High Water for tidal salt marsh to colonize as sea level rises. Regionally, there is a scarcity of naturally occurring transitions between tidal marsh and upland. Along the coast north and south of the mouth of the Eel River, there are areas where natural transitions occur between tidal marsh and upland coastal dune habitats. Otherwise, marsh/upland transitional habitat is lacking. Tidal marsh occurring in the Eel River estuary and associated sloughs are typically bounded on their upper margin by steep-sided levees. In Humboldt Bay to the north of the Eel River, the situation is similar, with natural marsh/dune transitions occurring on the North and South Spits, and the remaining periphery of Humboldt Bay and the margins of tidal sloughs bounded more or less abruptly by levees.

4.1 Success Criteria

4.1.1 Habitat Acreage Success Criterion

The HMMP final success criterion for habitat acreage is for restored habitats to be within ± 10% of the projected habitat acreages by Year 10 (HTH and Winzler & Kelly 2012). The objective of Year 1 monitoring is to assess whether habitat restoration is progressing along a trajectory that will meet project goals. Determination of whether the project is meeting habitat success criteria is best achieved by considering all habitats collectively. Evaluation of tidal marsh acreage was beyond HTH’s monitoring scope; however, it should be noted that acreage calculations for restored tidal marsh and high marsh ecotone habitats are inherently linked. The location of the boundary line mapped between these two types will affect the acreages of both habitat types. The ecological functions and values of these two habitat types are also linked. This study documented the establishment of early successional high marsh ecotone vegetation, dominated by


18 December 2014

native and non-native non-invasive species throughout an approximately 17.6 ac high marsh ecotone area. This surface area exceeds the HMMP’s projected high marsh ecotone surface area (12.4 ac). With further vegetation establishment and development at the site, it is expected that vegetation patterns will become more evident and that these patterns can be used to refine the high marsh ecotone boundaries when the habitat is re-mapped in future assessments. Boundaries may shift somewhat, especially at the south end of the project site where the transition from marsh to ecotone occurs overs a broad, gradual slope between 7.5–9.0 ft. Considering the proximity to the Salt River in this part of the site and gradual slope, the establishment of salt marsh vegetation may over time extend to slightly higher elevations in this section of the site. Wide transition zones with gentle gradients between marsh and upland are generally associated with greater biological diversity (Baye 2008).

4.1.2 Percent Cover Success Criteria

A mean cover of 24.1% by native plant species in the high marsh ecotone was significantly greater than the minimum 5% cover set as a Year 1 success criterion for this habitat type. This was largely due to the successful establishment of two native grasses, tufted hairgrass and meadow barley, both of which were components of the hydroseed mix applied as part of the restoration effort. Additionally, it is encouraging that natural recruitment by a number of native marsh species was observed in the created high marsh ecotone habitat. Adjacent restored salt marsh habitat has its own set of milestone success criteria to meet for minimum native plant cover, not addressed at this time. Quantitative monitoring for salt marsh will be initiated in Year 3. The Year 10 success criterion for both salt marsh and high marsh ecotone is a minimum of 60% native plant cover. Cover by invasive plant species and cover by non-native non-invasive plant species occurring in the high marsh ecotone were also assessed as part of this monitoring effort; however no milestone success criteria were specified by the HMMP. The Year 10 success criterion for all tidal wetland habitats (comprising over 300 ac of salt marsh in addition to the high marsh ecotone) is a maximum of 5% cover by invasive plant species and 15% by non-native non-invasive plant species. Evaluation of this criterion will require more comprehensive monitoring of all SRERP tidal wetland habitats as the project progresses. Nonetheless, it is not too early to consider what management actions are appropriate to move the project towards Year 10 goals. Total cover by invasive plant species in the high marsh ecotone was 1.1%. The presence of invasive Spartina is a trigger for control actions, as discussed in the following section. Total cover by non-native non-invasive plants was 18.5%. Most of this cover is attributable to fat-hen, an early seral plant that may decline over time as other species become established. Control actions for fat-hen are not considered warrantable at this time, nor is it expected that control will be needed in the future. Fat-hen has been encouraged in some managed brackish and saline marshes as a source of winter feed for ducks and other waterfowl (Sawyer et al 2009).


18 December 2014

4.2 Management Recommendations

Based on our Year 1 monitoring results for the SRERP high marsh ecotone, the main vegetation management concern we identified is the need for control of invasive Spartina. Invasive Spartina (Spartina densiflora) was detected in high marsh ecotone sampling, and also was observed occurring within the adjacent restored tidal marsh. SRERP Phase 1 restoration activities included removal of existing Spartina at the site. The need for ongoing management actions to control Spartina in SRERP restored areas was recognized as a high priority in the HMMP (HTH and Winzler & Kelly 2012). There is a regional Spartina eradication program in place (HTH 2013), with the Humboldt Bay Harbor, Recreation, and Conservation District serving as regional coordinator. Eradication of invasive Spartina is also the target of a coast-wide eradication effort (Boe et al. 2010). The greatest threat now posed by Spartina at the site is invasion of the restored salt marsh habitat. In fall 2014, HCRCD initiated Spartina removal in the salt marsh (Hansen, pers. comm.). Spartina control in the high marsh ecotone is also needed. Spartina stays green all year, and can be easier to detect, especially small plants, during the late fall–early spring when many other plants are dormant. Guidelines for site-specific evaluation of Spartina infestation, estimation of the resources needed for control, and selection of appropriate control methods are provided in the Humboldt Bay Regional Spartina Eradication Plan (HTH 2013). The level of threat posed by other invasive species to the high marsh ecotone is as yet unclear, and continued monitoring as scheduled is considered sufficient management action at this time. No other factors impeding the continued establishment and growth by native plant species in the high marsh ecotone were identified during Year 1 monitoring.

4.3 Future Monitoring

Sampling of the high marsh ecotone was conducted late in the growing season this year. Many plants were still standing and identifiable, and there was sufficient material present to determine that the Year 1 minimum success criterion for native plant cover in the high marsh ecotone was met. It is possible, however, that some annual plants were missed and that the cover and/or frequency of plants observed was under-represented. In future monitoring of the high marsh ecotone, it is recommended that field sampling occur earlier in the growing season, in June–August. While it is generally a good idea to monitor at a consistent time of season each year to facilitate comparison among years, in this case there would be a greater benefit in sampling at a time that would provide a more comprehensive assessment of vegetation condition. Additionally, success criteria have been set independently for specific monitoring years, and do not require direct analysis in terms of changes in relation to previous years. The next time the high marsh ecotone is scheduled for percent cover assessment is Year 2 (2015), and for habitat acreage assessment is Year 3 (2016).


18 December 2014

Section 5.0 References

Baldwin, B. G., D. H. Goldman, D. J. Keil, R. Patterson, T. J. Rosatti, and D. H. Wilken. 2012. The Jepson Manual: Vascular Plants of California. Second Edition. University of California Press, Berkeley, California.

Baye, P. R. 2008. Vegetation Management in Terrestrial Edges of Tidal Marshes, Western San Francisco

Estuary, California: Integrated Vegetation Management Strategies and Practical Guidelines for Local Stewardship Programs. Marin Audubon Society, Mill Valley, California.

Boe, J., A. Boone-Vierra, W. Brown, T. Butler, J. Gerwein, M. Herborg, P. Olofson, M. Spellman, J. Steger,

M. Sytsma et al. 2010. West Coast Governors’ Agreement on Ocean Health Spartina Eradication Action Coordination Team Work Plan.

Braun-Blanquet, J. 1928. Pflanzensoziologie. Gründzuge der Vegetationskunde. Springer-Verlag, Berlin,

Germany. Calflora. 2014. Information on California Plants for Education, Research, and Conservation (Web

Application). The California Database, Berkeley, California. [online]: http://www.calflora.org. Accessed 31 October 2014.

[CDFA] California Department of Food and Agriculture. 2014. California Noxious Weed List. [online]:

http://www.cdfa.ca.gov/plant/ipc/weedinfo/winfo_table-sciname.html. Accessed 15 October 2014. [Cal-IPC] California Invasive Plant Council. 2014. Online database. [online]: http://www.cal-ipc.org/ip/

inventory/. Accessed 29 September 2014. Collins, J. N. and R. M. Grossinger. 2004. Syntheses of Scientific Knowledge for Maintaining and Improving

Functioning of the South Bay Ecosystem and Restoring Tidal Salt Marsh and Associated Habitats Over the Next 50 Years at Pond and Pond-complex Scales. San Francisco Estuary Institute. Report No: 308.

DiTomaso, J. 2003. Cal-IPC Plant Assessment Form for Lolium multiflorum/Festuca perennis. Elzinga, C. L., D. W. Salzer, and J. W. Willoughby. 1998. Measuring and Monitoring Plant Populations.

Bureau of Land Management, Denver, Colorado. Technical Reference 1730-1.

http://www.calflora.org/

http://www.cdfa.ca.gov/plant/ipc/weedinfo/winfo_table-sciname.html

http://www.cal-ipc.org/ip/inventory/

http://www.cal-ipc.org/ip/inventory/


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GHD. 2014. Field Map Showing Locations and Dates of Hydroseeding, with a Copy of a Seed Tag Listing the Salt River Seed Mix 5 (High Marsh). Materials submitted to Humboldt County Resource Conservation District.

[HTH] H. T. Harvey & Associates. 2013. Humboldt Bay Regional Spartina Eradication Plan, Final Report.

Project 3192-01. California Coastal Conservancy, Oakland, California. [HTH] H. T. Harvey & Associates and Winzler & Kelly. 2012. Salt River Ecosystem Restoration Project

Habitat Mitigation and Monitoring Plan. Report prepared for the Humboldt County Resource Conservation District.

[HWMA] Humboldt County Weed Management Area. 2010. Strategic Management Weed Lists, May 2010.

Lists compiled by the Humboldt County Weed Management Area, Arcata, California. Leppig, G. and A. Pickart. 2013. Vascular Plants of Humboldt Bay’s Dunes and Wetlands. Release 3.0, June

2013. U.S. Fish and Wildlife Service and California Department of Fish and Wildlife, Eureka, California.

Pickart, A. 2006. Vegetation of Diked Herbaceous Wetlands of Humboldt Bay National Wildlife Refuge:

Classification, Description, and Ecology. U.S. Fish and Wildlife Service, Humboldt Bay National Wildlife Refuge, Arcata, California.

Sawyer, J. O., T. Keeler‐Wolf, and J. M. Evens. 2009. A Manual of California Vegetation. Second edition.

California Native Plant Society, Sacramento, California. [USDA] United States Department of Agriculture. 2014. Federal Noxious Weed List. [online]: http://plants.

usda.gov/java/noxious. Accessed 15 October 2014. Personal Communications Hansen, D. Humboldt County Resource Conservation District. Meeting with A. Eicher, H. T. Harvey &

Associates, 26 November 2014. Pickart, A. Humboldt Bay National Wildlife Refuge. Meeting with A. Eicher, H. T. Harvey & Associates, 16

October 2014.

http://plants.usda.gov/java/noxious

http://plants.usda.gov/java/noxious

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