Lars Anderson, PhD WaterweedSolutions

Inverness, CA- USA

Successful Management & Eradication of Aquatic Weeds

Defining the Problem and Setting Goals Growth, Reproduction in Aquatic Plants Strategies and Tools: Control and Eradication Some Examples: Hydrilla, Egeria Technologies for Eradication and Monitoring

Topics:

Successful Responses to Aquatic Invasive Species

Hydrilla verticillata (Eradication in California)* Caulerpa taxifolia (Marine alga) (Eradication in Calif.) Sabellid worms in abalone (Eradication) Eichhornia crassipes (Management, world-wide)* Salvinia molesta (Management, some sites eradicated)* Egeria densa (Management, US, Brasil?) Elodea canadensis (Australia, Europe, US) (Management) Alligatorweed (near-eradication in California)* Weeds in irrigation systems (Management, worldwide)* * Included use of biological control agents

Components of Successful Management or Eradication Projects

Invasive, Nuisance Plant

Identification

Biology & Phenology

Experience and

knowledge:

Implement, containment,

control or eradication

Knowledge of

infested site(s):

Invasion pathways,

Habitats, Uses,

Nontarget effects,

Laws, Stakeholders

Goals Resources:

Funds Personnel Equipment

after Anderson 2005

Science and Technical Advisory

Public Outreach

External Review (Transparency and

Credibility)

WATER: It’s Essential ! Water from the Sacramento-San Joaquin Delta, California: > 25 million Californians drink it! Egeria densa covered with algae- 2005

Myriophyllum spicatum

Negative Impacts of Un-Managed Elodea Will Spread to more Lakes, Reservoirs, Rivers, Streams

Flood control (combination of riparian and aquatic weeds)

Navigation (recreational, law-enforcement and commercial vessels)

Recreational Uses and Revenues: swimming, fishing, boating

Native habitats (waterfowl, fish, invertebrates, plants)

Water quality (dissolved oxygen, pH, nutrients, organic loading)

Sediment (nutrients and metals loading)

Health (mosquito habitat)

Reduced Property values and Tourism Revenue

SOURCES OF CONTINUED SPREAD

Prerequisites for Spread of

M. spicatum and P. crispus, Elodea:

Production

of Viable

Propagules

Propagule

Transport

Suitable

Habitat

Seeds

Fragments

Turions

Rhizomes

Wind

Currents

Boats

Float-

planes

Birds

Shoreline protected form high wind, waves;

Sandy/Organic/Silty bottom;

Adequate Nutrients and Light

M.-H. Barrat-Segretain et al. / Aquatic Botany 74 (2002) 299–313

S=Spring A= Autumn

60 N Lat.

50 N Lat.

Elodea canadensis In Latvia (<1900-2008)* *From: Grinberg, L. and Priede A. 2012. Elodea canadensis Mishx in Lativia. Acta Biol. Univ. Daugavp. 10: 43-50.

NOTE: First reported in 1872 (Associated with timber transports) >Found in low and high nurtrient conditions

Prior to 1900

1901-1950

1951-2008

The Risks of Invasive Aquatic Plants

..and The risk of delayed action… or no action

Ecosystem Functions

Nuisance Species

Other “Stressors”

Ecosystem-Level Demands

Ecosystem or Aquatic Site

Beliefs: We Can Balance Risk and Benefits

Linkage Resistance: Resiliency

Action? Ecosystem Services

Ecosystem Functions

Beliefs: We Can Balance Risk and Benefits

Linkage Resistance: Resiliency

Management Action?

Invasive Species:

Shift in Stable point:

Ecosystem

Functions?

Invasive Species

Other “Stressors”

Ecosystem-Level Demands

Ecosystem or Aquatic Site

Beliefs: Just Control the Obvious Weed “Squeaky Weed” Approach !

Linkage Resistance: Resiliency

Management Action: Single Species

Ecosystem Services

Invasive Species:

Shift in Stable point:

Submersed Aquatic Vegetaton Establishment, Growth and Dispersal Sub Model

Salinity

Temp

Turbidity

Light

SAV Establishment

and Growth

Sustainable

SAV Population

-

+

+

+ -

- -

Local Flow Conditions (velocity, residence time)

pH Nutrients

+ +

DIC

- +

DO

+/-

Shallow depths, Gentle slopes

+ + +

Higher velocity, larger bed grain

size

Substrate stability

Dispersal +

- + +

+

+

-

Understanding:

High – green arrow

Med – blue arrow

Low - red arrow

Importance: High – thick line

Med – medium line

Low – thin line

Predictability:

High – solid line

Med – dashed line

Low – dotted line

-

-

Boxes are Drivers

Arrows show Linkages

Ovals are Outcomes(Driver effects)

See Hydrodynamic Model

(3) Sediment Characteristics (4) Nutrient in sediments (5) Anchoring

(8)Local Flow Conditions

(1)High Light Levels (2) Atmospheric C02

Management Actions Can act on any of these “drivers” to shift population abundance

Aquatic Plant Resource Requirements for Establishment, Growth and Dispersal

(6) Low Light Levels (7) Dissolved Carbon (DIC) Sources

(9) Water Quality (10) Nutrients in Water

Floating Plants Emergent Plants

Arrows show resources acquired through common driver-pathways (overlapping circles) among the three ecological/ growth forms of aquatic plants: Emergent, Floating and Submersed. Overlaps occur where the plant types share access to resources and where drivers Impact both plant types.

Submersed Plants

Temperature Temperature

Some have spectacular flowers! Hydrilla flowers - Porto Primavera, Brazil

Pollination in aquatic plants:

Floating Plants: Insects (e.g. moths)

Emergent Plants: Wind, Insects

Submersed Plants:

•Wind (on emergent spiklets, e.g. Myriophyllum, Potamogeton spp)

•Explosive, projectile dispersal of pollen (hydrilla)

•Insects (probably infrequent) (emerged small flowers or spiklets)

•Underwater pollination= “hydrophily” >Zannichellia (horned pondweed), Najas and Potamogeton, and in Zostera and Phyllospadix (two marine angiosperms) pollen is modified as sticky, filamentous and string-like, or may have a partially emerged pollen tube

Can Carbon and Nutrients Limit Aquatic Vascular Plants?

•Probably NOT nutrients in most “urban settings”: >Tissue levels 1 to 4 % N are typical >P is cycled rapidly and is seasonally replenished; sediments provide a major reserve of nutrients >Reducing P can reduce algae growth dramatically

•Carbon could limit submersed plants- but Photosynthetic plasticity can compensate for changes in species of carbon that dominate

•What then limits establishment and growth? >Substrate stability/type, water velocity and inter-species competition for space and light are primary drivers

Sources of Carbon and Nutrients for Aquatic Vascular Plants Floating Plants: Dissolved N, P, K, micronutrients in water; Atm. CO2 (increasing !) Water hyacinth, S. Amer. Spongeplant and NATIVE PLANTS

Emergent Plants: Sediment NPK, micronutrients, Atm. CO2 (Now increasing) Arundo donax, Phragmites, Lythrum salicaria (Purple loosestrife), Ludwigia species and NATIVE PLANTS

Submersed (rooted) Plants:(Physiological plasticity) 80-95+% Sediment NP(K), micronutrients 10-20% Dissolved N, P, K, micronutrients in water Dissolved CO2, HCO3(increasing) (C-3, C-4, CAM-like PS) E. densa, P. crispus, M. spicatum, Elodea sp. , , and NATIVE PLANTS

• Pathways • Vectors

• Dispersal • Water quality

• Non-target effects • Regulatory compliance • Species interdependence

• Impaired Aquatic Ecosystem Services

Biological, Emotional and Economic Connections to water

Perceptions of Risk from Invasive and Nuisance Plants

& Perceptions of Risk From

Management Actions

Science-Based Balance of Risk and Benefit

CONSENSUS FOR ACTIONS

Preventing horticultural introductions of invasive plants: potential efficacy of voluntary initiatives

Jennifer W. Burt Æ Adrianna A. Muir Æ Jonah Piovia-Scott Æ Kari E. Veblen Æ Andy L. Chang Æ Judah D. Grossman Æ Heidi W. Weiskel 2007 Biol. Invasions

Public Education, Quarantines, Monitoring, Enforcement

Lake Tahoe: A Cautionary Story about Invasive Species

1880 1900 1940 1920 1960 1995 1980 2008 2003 2007 2006 2011 1970

brown, rainbow, brook, lake trout

Establishment of lake trout

crayfish

kokanee

Mysis Tahoe Keys Built

Lake Tahoe Exotic Aquatic Species Introduction (Detection) Timeline

bass spp.

Asian clam

extirpation of cutthroat trout & Daphnia spp.

RESPONSES

USDA-ARS:Whole Lake Plant Surveys

ARS-TRCD Org. AIS Workshop

AIS Working Group

AIS Coordinating Committee; USFWS-Coordinator

AIS Plan Approved 2009, TRPA and USFWS appoint AIS coordinator

Eurasian watermilfoil Curlyleaf

pondweed ?

1st Zebra mussel Interdiction on boat- prevented from launching

After Sudeep Chandra (Univ.Nev-Reno); modified and updated by Lars Anderson (USDA-ARS-Davis, CA)

?

Asian clam Removal begun

Aquatic Plant Harvester- Transferring a load to the shore- Immediate “Solution”, but

Spreads plants

Tahoe Keys: Annual Cost of Weed Harvesting (130 acres)

Cost Wages/benefits $118,700 Supplies 8,900

Weed disposal 22,400

Admin 28,800

Vehicle 5,300

Insurance 26,800

O&M and Replacement 34,000

Misc 14,800

TOTAL $259,700

Costs for Bottom Barriers*

• Synthetic ~$100,000 per acre

• Jute ~$65,000 per acre

• Piers and excessive plant

density decreased efficiency

*Based on 2012/2013 studies

0

5

10

15

20

25

1990 1995 2000 2005 2010

M. spicatum

P. crispus Mainly

Tahoe

Keys and

South

Shore

Recent

Increase

Mainly on

West

Shore

Spread of M. spicatum and P. crispus

at Lake Tahoe*

Number

of sites

infested

*Based on USDA-ARS Surveys

• Lake Tahoe region will be

infested by boats arriving from

other regions

• In turn it may infest lakes

within our region

M.E. Wittmann, UC Santa Barbara dissertation unpubl.

PPropagule Pressure

M.E. Wittmann, UC Santa Barbara dissertation unpubl.

Invasion/ Nuisance Process-Driven Management

Transport Introduction Establishment Spread Increased impacts Increased Spread Rate

Fewer options Higher

non-target risk and

Increased costs

Responses to Aquatic Plant Infestations: Three Options for “Risk Management”

Option 1 Do Nothing: • Further spread

locally • Spread to more

lakes, rivers, streams

• Reduced fish and waterfowl habitat

• Impaired water quality

• Long-term very high cost

• Liability ($)? • Degraded

Ecosystem Services

Option 2 Manage to some “threshold”: • Reduction locally • Initially lower cost • Continued source

for further spread • Localized major

impacts and costs • Long-term,

continued and growing cost and liabilities

• What is an “acceptable” infestation?

Option 3 Eradicate: • Stop further spread • Eliminate target

plants and propagules • Initially higher cost • Protection of

suceptible sites • Improved Readiness

for the next invasions • Public credibility • Reduced liability • Clear, consistent

goal and endpoint • Lower long-term

cost

Probable Outcomes

Action >

Western Hydrilla History First Identified 1976 (Marysville & Imperial Irrigation System) Threat to Rice production + ca. $ billion Ag. Production Declared “A”-rated pest/ eradications begun 1977.

Costs range from $1.5 to 2 million/year About 34 sites have been found in 30 years Washington’s site is near eradication (Pipe/Lucerne Lakes) No hydrilla has been documented for Oregon Idaho populations under eradication (funding is questionable!) Eradication has been achieved in most sites and is on-going (few plants left) in nearly all the active eradication sites

Aquatic Sites Where Hydrilla Has Been Eradicated

Small ponds (1 to 10 acres) Lakes (e.g. Spring Lake; Lake Ellis, Lake Murray) (100’s of Ac) Aquascapes Nurseries Irrigation Systems (small, medium, large>>500 miles of canals) (Thanks to triploid Grass Carp!) Reservoirs (Eastman); Sheldon Res.

Recalcitrant Sites Under Eradication:

oClear Lake (44,000 acres)

Hydrilla Distribution in US

US- Waterways (Rivers, Reservoirs)

Hydrilla Eradication in California and Washington states has kept it

out of nearly all western US waterways

IPCM: Integrated Plant Community Management

Integrating Control Technologies: 1. Phenology/life cycle (seasonal timing) Seed germination; sprouting of

vegetative propagules) Onset of growth Propagule formation Senescence and “over-wintering” Competitive plant Community?

IPCM: Integrated Plant Community Management

Integrating Control Technologies: 2. Biological Control and Microbial Uses Host Specificity Efficacy (Phenological match;

Rhizosphere/microbial interactions) Adequate Source, Dispersal, Growth Predation, Pathogens and Competitors of

Control Agent? Monitoring populations and rhizosphere

effects

IPCM: Integrated Plant Community Management Integrating Control Technologies:

3. Physical Removal methods Minimize Propagule Spread Plant Removal (Cutting, Suction) Substrate (sediment) Removal Water Quality Protection (turbidity) Non-target of fish and benthic species Disposal and “quality” of materials

IPCM: Integrated Plant Community Management

Integrating Control Technologies: 4. Physical Covering (Bottom Barriers) Materials (synthetic, jute, cement) Timing and Duration (Before onset of

spring growth) Suitable substrate for anchoring Efficacy: Seed bank longevity? Disturbances during installation? Non-target effects (benthic organisms) Compatibility with site/water uses

IPCM: Integrated Plant Community Management Integrating Control Technologies:

5. Herbicides Approved Label Efficacy Spectrum and Mode of Action Formulation(s) Timing, Placement, Proper Rates Water Movement (Dilution, Contact) Water Levels (Drawdown?) Monitoring, QA/QC

Entry Routes for Aquatic Herbicides

Foliage- Air Applications

Foliage- in Water

Roots in Water

Bottom Placement (pellets)

Roots and Propagules in Sediment

Targeting for Optimal Efficacy of Aquatic Herbicides

Mode of Action !

Required Herbicide Contact Time

acrolein xylene diquat Cu-chelate

Cu-inorg. triclopyr

glyphosate endothall

imazamox diclobenil

Other ALS 3-5 wks

0 20 40 60 80 100 120 140 160 Approximate Hours Needed

Herb

icid

es

fluridone 6-10wks

WEEKS >>

Best Options for Eradication of Elodea: Fast-acting Contact and Effective Systemic Herbicides

Aquatic Herbicides: Modes of Action Mode of Action>>>> Active Ingredient

Group 2/ALS (B)

PPO (Protox inhibitor) (Group 14) (E)

Systemic (Group 12) (F1)

Systemic (Group 9)

Systemic (Group 4) (O)

Contact (Group 22) (D)

Contact (Nucleic acid inhbib?)

Bispyribac-sodium

x

Carfentrazone x

Flumioxazin x Imazamox x Penoxsulam x

Fluridone x

Triclopyr x 2,4-D x

Diquat x

Endothall x Imazapyr x

IPCM: Integrated Plant Community Management Integrating Control Technologies:

6. Promote Native Plants Sources and establishment Suitable conditions (substrate, light,

nutrients, water movement) Suitable match with plant phenology Compatibility with site/water uses Population monitoring

IPCM: Integrated Plant Community Management Monitoring:

(Pre & Post Management Actions) Efficacy Analysis Aerial Hyperspectral Analysis GPS-referenced Hydroacoustic Analysis GPS-referenced Point-Sampling GPS-referenced Herbicide Residues Water Quality Fish & Benthos Sampling Biocontrol Agent Status Native Plant Status

Smart Application and Monitoring Monitoring Technologies and Strategies:

Rapid herbicide assays (24-48 hr) Remote controlled sensing submersibles GPS-linked Hydroacoustic analysis GPS-linked videography (in clear water) Precision flow and dispersal modeling:

>Automatic Doppler Velocity Instruments >Tracer dye (Rhodamine WT)

In-situ plant condition & response assessments Bioassays using explants and surrogates

Smart Management and Monitoring

Use Integrative and Consensus-Driven Approaches Create interdisciplinary teams Promote culture & ethic of “transparency” Combine and integrate proven methods for

maximum efficacy and minimum non-target effects

Consult with stakeholders at EVERY phase Promote flexibility and adapt to changes Invite outside reviews and assessments Readjust actions based on reviews & results

Summary

Hydroacoustic (Sonar) Assessment:

0 0 0 0 0 0 30 30 35 45 70 75 65 70 70 0 55 45 0 0 height (cm) 150 140 130 125 120 115 115 115 110 110 110 110 110 110 115 120 125 130 135 140 depth (cm)

DGPS (1) DGPS (2) DGPS (3)

Graphic courtesy of

Acoustical Sensing Technologies

Dazzling Delta Data 492,000 acres (wetland, sloughs, farmlands)

Water for over 25 million Californians

Irrigated crops: $27 billion per year

Supports over 500 species fish/wildlife/plants

Home of >20 Endangered species

1,000 miles of levees

>60,000 acres of water surface

Tidal (diurnal) cycles and seasonal discharges

12 million “Recreational User Days” SF Bay

Sacramento-San Joaquin Delta

Sponsored by the California Department of Boating and Waterways (CDBW).

Dr. Susan L. Ustin, Principal Investigator

Center for Spatial Technologies and Remote Sensing (CSTARS), University of California, Davis.

2005: Hyperspectral Remote Sensing for Egeria densa

2006: ca. 6,000 acres

Franks Tract: 3,000 acres

Boat-Mounted Hopper/ Spreader for Granular

Formulations

Weighted Hoses for Injection

Boat-Mounted Hose for Applications of Liquid

Formulation Underwater

Sacramento- San Joaquin Delta Egeria densa Management:

Apply Fluridone Weekly for 8-10 weeks Methods for Applying Liquid or Granular Fluidone

2004

2005

2006

2007

Submersed plant distribution maps from hyperspectral imagery collected in June

500m

80 % Reduction in Biovolume 1 year Posttreatment

Release of Stuckenia pectinata after Management of E.densa (Sacramento Delta)

US-EPA Registered Aquatic Herbicides

• Acrolein (Magnecide-H) • 2,4,-D (Weedar) • Endothall (Aquathol-K, Cascade, Teton) • Copper elemental & Chelates • Diquat Dibromide (Reward) • Fluridone • Gylphosate (Rodeo, Aquamaster etc.) • Trichlopyr (Renovate) (2003) • Imazapyr (Habitat) (2003) • Penoxsulam (Galleon) (2007) • Imazamox (Clearcast) (2005) • Cafentrazone ethyl (Stingray) (2007) • Bispyribac sodium (Tradewind) (2007) • Flumioxazin (Clipper) (2007) • Quinclorac (2007)