Microsoft Word - Lygodium_microphyllum_japonicum_&_flexuosum_WRA_20090512

United States

Department of

Agriculture

Animal and Plant

Health Inspection

Service

May 2009

Rev. 05

Lygodium microphyllum (Old world

climbing fern), Lygodium japonicum

(Japanese climbing fern), and Lygodium

flexuosum

Weed Risk Assessment

Agency Contact:

United States Department of Agriculture

Animal and Plant Health Inspection Service

Plant Protection and Quarantine

Center for Plant Health Science and Technology

Plant Epidemiology and Risk Analysis Laboratory

1730 Varsity Drive, Suite 300

Raleigh, NC 27606

Left: Lygodium microphyllum on cypress trees (Peggy Greb, USDA Agricultural Research Service, Bugwood.org).

Right: Lygodium japonicum in pine forest (James H. Miller, USDA Forest Service, Bugwood.org).

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Rev. 005 May 12, 2009

Table of Contents

1. Initiating Event............................................................................................................................ 1

2. Plant Identity............................................................................................................................... 1

3. Current PPQ Policy..................................................................................................................... 1

4. Data Sheet(s) and Other Risk Assessments................................................................................ 1

5. Pest Characterization .................................................................................................................. 2

5.1. Distribution, Prevalence, and Potential Pathways of Entry................................................. 2

5.2. Weed Biology and Impact ................................................................................................... 3

5.3. Current Response and Activities.......................................................................................... 4

5.4. Plant Protection Act’s (PPA) Definition of Noxious Weed................................................. 4

6. Risk Assessment ......................................................................................................................... 4

6.1. Establishment/Spread Potential ........................................................................................... 4

6.2. Potential Impacts: Production, Environmental, and Human/Social..................................... 5

6.3. Geographic Potential............................................................................................................ 7

6.4. Entry Potential ..................................................................................................................... 7

6.6. Recommendations................................................................................................................ 9

7. Contributors ................................................................................................................................ 9

8. Figures....................................................................................................................................... 10

Figure 1. County level distribution of Lygodium microphyllum in the lower 48 states............ 10

Figure 2. County level distribution of Lygodium japonicum in the lower 48 states................. 11

9. References................................................................................................................................. 12

Appendix A................................................................................................................................... 19

Appendix B................................................................................................................................... 32

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1. Initiating Event

APHIS received an inquiry regarding market access for leaves of

Lygodium microphyllum from China to be used in basket-weaving

(Lehtonen, 2008). Lygodium microphyllum and its congener, L.

aponicum, are already present in the United States, where they are

listed as state noxious weeds in Florida and Alabama (NRCS, 2008).

Lygodium japonicum is also used in Asian handcrafts (fern fronds)

(Ferriter, 2001). Historically, this species has been confused with L.

microphyllum (FDEP, N.D.; Pemberton and Ferriter, 1998). Because

importation of L. microphyllum and L. japonicum may lead to the

establishment of additional populations in the United States, Plant

Protection and Quarantine (PPQ) requested that PERAL prepare a weed

risk assessment to evaluate listing these species as Federal Noxious

Weeds (Tasker, 2008). L. flexuosum, which is not in the United States,

was also assessed because it is similar to these other two species, and

may have similar impacts if introduced. We assessed all three species

together in this document

2. Plant Identity

Lygodium microphyllum (Cav.) R. Br.

Syn: Lygodium scandens auct. and Ugena microphylla Cavanilles

Lygodium japonicum (Thunb.) Sw.

Syn: Ophioglossum japonicum Thunb.

Lygodium flexuosum (L.) Sw.

Syn: Ophioglossum flexuosum L.

References: (ARS, 2008a)

3. Current PPQ Policy

None of these species is listed as a Federal Noxious Weed (queried

April 29, 2008). PPQ issued a Federal Import Quarantine Order on May

30, 2008 to prevent the importation of L. microphyllum and L.

lexuosum.

4. Data Sheet(s) and Other Risk Assessments

The State of Florida requested that APHIS assess/list the entire genus of Lygodium. In this document, we only

assessed species for which there was ample evidence of harm. A preliminary review of the literature indicated that

of the approximately 25 species in the genus (Mabberley, 2008), only two other species have been considered

weeds: L. polymorphum and L. circinnatum (Holm et al. 1979). Due to the limited amount of information available

on these two species, they will be assessed separately after PPQ completes developing a predictive weed screening

tool. No other species of Lygodium have been noted in the literature to be weeds.

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PPQ has not formally evaluated these species. Gordon et al. (2008b)

assessed L. microphyllum and L. japonicum in their test of the

Australian weed risk assessment system in Florida. Because these two

taxa are generally considered major invaders (e.g., Weber, 2003),

numerous reports are available about them (e.g., Brandt and Black,

2001; ISSG, 2008; Masterson, 2007; Wu et al., 2006).

5. Pest Characterization

5.1. Distribution, Prevalence, and Potential Pathways of Entry

Lygodium microphyllum is native to tropical Africa, India, southeast

Asia, Taiwan, and portions of Malaysia and northern Australia (ARS,

2008a; Langeland and Burks, 1998). The native range includes the

following countries: Kenya, Tanzania, Uganda, Burundi, Cameroon,

Gabon, Zaire, Cote D’Ivoire, Ghana, Guinea, Guinea-Bissau, Liberia,

Nigeria, Senegal, Sierra Leone, Angola, Mozambique, Zambia,

Zimbabwe, South Africa, China (Fujian, Guangdong, Guangxi,

Yunnan), Japan (Ryukyu Islands), Taiwan, India, Thailand, Brunei,

Indonesia, Malaysia, Papua New Guinea, Philippines, Australia,

Micronesia, and Fiji (ARS, 2008a; Langeland and Burks, 1998; NTU,

2008).

Lygodium microphyllum is also currently established in the United

States in twenty counties of peninsular Florida. The oldest known

collection is from 1958 (Loxahatchee River area), but it had probably

been in cultivation since at least the early 1950s (Nauman and Austin,

1978). It was probably introduced as an ornamental, as was its invasive

congener, L. japonicum (Gordon and Thomas, 1997). A molecular study

suggests that the U.S. population of L. microphyllum probably

originated from Australia/Papua New Guinea (Goolsby et al., 2006).

Where it occurs in natural areas, L. microphyllum is very abundant

(Hutchinson et al., 2006). Lygodium microphyllum has not yet reached

the limit of its potential geographic distribution in the United States (see

geographic potential below and Figure 1).

Lygodium japonicum is native to tropical and temperate Asia, from

Malaysia and Papua New Guinea northward to Taiwan, Japan, and

Korea (ARS, 2008a). Its native range includes China, Japan, Korea,

Bhutan, India, Nepal, Sri Lanka, Cambodia, Laos, Thailand, Vietnam,

Indonesia, Malaysia, Papua New Guinea, and the Philippines (ARS,

2008a). It appeared in a U.S. nursery catalog as early as the 1880s and

was probably introduced as an ornamental species at the same time

(Pemberton and Ferriter, 1998). It has been established since at least

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1937 (Soxman, 1939)

. It is also established in Puerto Rico and Hawaii

(Liogier and Martorell, 2000; NRCS, 2008). Lygodium japonicum is

relatively widespread in some states, but more regionalized or isolated

in others (Figure 2) (NRCS, 2008). In the latter states, L. japonicum

may not have reached the limit of its potential geographic distribution

(USDA plant hardiness zone 8), and may spread further north (see

geographic potential below). For example, researchers in Georgia report

that after being present for some time, “…the population now seems to

be spreading at an alarming rate” (Evans and Moorhead, 2005). Besides

being spread through horticulture, it is readily wind-dispersed (Ferriter,

2001) and can spread in contaminated pine-straw and on field

equipment (Miller, 2007).

Lygodium flexuosum is native to temperate and tropical Southeast Asia

and Australia. It has been reported from Australia, China, India,

Indonesia, Malaysia, Nepal, Papua New Guinea, the Philippines, Sri

Lanka, and Thailand (ARS, 2008a; Dangol, 2005). Other than for

iocontrol research at a quarantine facility in Gainesville (ARS, 2008b),

we found no evidence of it being introduced to the United States.

Several species of Lygodium, including L. microphyllum and L.

aponicum, are cultivated as ornamentals (Bailey and Bailey, 1976;

Wiersema and Leon, 1999). Lygodium flexuosum is also likely to be

cultivated, since one seed order company lists it in its online catalogue

(Anonymous, 2008) and it is used in basket weaving (Anonymous,

2005). We found no evidence that any of these species have been

domesticated or bred for any particular traits.

5.2. Weed Biology and Impact

All three species are ferns with a vine-like growth form. Fronds of

Lygodium japonicum and L. microphyllum grow up to 30 feet long,

capable of reaching into forest canopies (Ferriter, 2001; FNA Editorial

Committee, 1993; Pemberton and Ferriter, 1998). They can blanket

entire communities, shading out plants below, and, importantly,

providing a means for fire to reach tree canopies (Ferriter, 2001;

Munger, 2005; Pemberton and Ferriter, 1998). In the United States, they

invade many different habitats, including wet (mesic) habitats, ditches,

hammocks, pine forests, wetlands, and disturbed areas (Ferriter, 2001;

ISSG, 2008). Lygodium flexuosum is a weed of rice fields and rubber,

oil palm, and tea plantations, where it competes with plants and

obstructs harvesting (PIC, 2008; Rajkhowa et al., 2005; Roder et al.,

1995b; Roder et al., 1997). All three species are agricultural weeds in

their native range (Holm et al., 1979).

The USDA Plants Database currently indicates its presence in Pennsylvania (NRCS,

2008), but this report is going to be removed because the original reference is

unverifiable and dubious (Skinner, 2008).

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5.3. Current Response and Activities

Lygodium microphyllum and L. japonicum are state noxious weeds in

Florida and Alabama; the other eight states with known populations of

L. japonicum (Figure 2) do not list this species as a noxious weed

(ADAI, 2008; Ferriter, 2001; NRCS, 2008). Outside of Florida, L.

aponicum is controlled locally by various federal, state, or local

agencies [e.g., Georgia (Evans et al., 2005), Texas (Korn et al., 2007;

USDA-FS, 2007), and Mississippi River bottomland forests (Stanturf et

al., 2004)]; however, the extent of local control is unknown. A survey o

control measures for L. microphyllum in southern Florida highlighted

the range of agencies managing it (Hutchinson and Langeland, 2006).

To help coordinate control efforts, a detailed management plan for L.

microphyllum was released two years ago (Hutchinson et al., 2006); a

similar one is planned for L. japonicum. Both species are subject to

intense monitoring and research (Carmichael and Platt, 2007; Clarke et

al., 2007; Lott and Volin, 2003; Lott et al., 2003; Pemberton, 2003;

Schmitz, 2007). In Florida, where both species are abundant (Wunderlin

and Hansen, 2008), the Florida Department of Environmental Protection

has spent approximately $15 million over the last ten years to control

and study them (Sole, 2008).

5.4. Plant Protection Act’s (PPA) Definition of Noxious Weed

To be listed as a Federal Noxious Weed, a plant must meet the

definition of a Noxious Weed in the Plant Protection Act (7 U.S.C. §

7701-7786, 2000). The term “noxious weed means any plant or plant

product that can directly or indirectly injure or cause damage to crops

(including nursery stock or plant products), livestock, poultry, or other

interests of agriculture, irrigation, navigation, the natural resources of

the United States, the public health, or the environment” (7 U.S.C. §

7701-7786, 2000). APHIS lists in the Federal noxious weed regulations

those species that are prohibited or restricted from entering the United

States, or moving interstate, and for which authority exists under

sections 412 and 414 of the PPA for APHIS to apply remedial

measures.

Based on the information described above, all three species meet the

PPA definition of noxious weed.

6. Risk Assessment

6.1. Establishment/Spread Potential

Lygodium microphyllum and L. japonicum have already demonstrated

their ability to establish and spread beyond their native range, having

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naturalized in other places outside of the United States (Liogier and

Martorell, 2000; Pemberton and Ferriter, 1998; Randall, 2007). In the

United States, they are considered invasive species that have rapidly

spread across the region (Ferriter, 2001; Hutchinson et al., 2006;

Pemberton and Ferriter, 1998; Volin et al., 2004; Wilson, 2002). For

example, in Florida, L. microphyllum has increased in coverage nearly

ten-fold in a decade (27,000 acres in 1993 vs. 120,000 acres in 2005;

Hutchinson et al., 2006). And although L. japonicum has been

established since at least 1937 in the United States (Soxman, 1939), it

continues to spread “at an alarming rate” (Evans and Moorhead, 2005).

We assessed the establishment and spread potential of all three species

using the 26 questions for this risk element listed in Appendices A & B.

Although not necessary because they have already demonstrated their

ability to spread, we did a full assessment on L. microphyllum and L.

aponicum to evaluate which traits may have contributed to their

invasiveness in the United States (Appendix A). On a scale of -22 to 28,

where 28 represents a species scoring positively on all invasive traits, all

three species scored relatively high (Table 1). Lygodium flexuosum

scored somewhat lower (12) than L. microphyllum (18) and L.

aponicum (17), primarily because of the first question about invasive

status elsewhere (Appendix B).

Our review suggests that the following traits have contributed greatly to

the establishment, naturalization, and spread of L. microphyllum and L.

aponicum in the United States: 1) tolerance to a wide range of light

conditions; 2) massive amounts of spore production; 3) long-distance

wind dispersal of spores; 4) self-compatible gametophytes; 5) tolerance

to fire; 6) relatively rapid growth rates and photosynthetic rates; and 7)

regional spread via several pathways (FDEP, N.D.; Ferriter, 2001;

Hutchinson et al., 2006; Hutchinson and Langeland, 2006; Lott and

Volin, 2003; Lott et al., 2003; Masterson, 2007; Miller, 2007; Nauman

and Austin, 1978; Pemberton and Ferriter, 1998; Volin et al., 2004).

Lygodium flexuosum possesses many of these same traits.

6.2. Potential Impacts: Production, Environmental, and

Human/Social

Lygodium microphyllum and L. japonicum invade pristine habitats,

disturbed areas, forest plantations, and rangelands (Ferriter, 2001;

Handley, 2008; Miller, 2003; Pemberton and Ferriter, 1998; Rowe,

2008; USDA-FS, 2007). Their prolific growth shades underlying

vegetation and promotes fire in plant canopies, thereby changing fire

regime, altering habitat structure, reducing native plant diversity, and

threatening rare species (Brandt and Black, 2001; Ferriter, 2001;

Hutchinson et al., 2006; Pemberton and Ferriter, 1998). Lygodium

microphyllum often creates a one-meter thick mat of live and dead fern

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fronds (Pemberton and Ferriter, 1998). Treating Lygodium infestations

in natural areas with herbicides and mechanical means can result in non-

target impacts to native communities (Hutchinson et al., 2006;

Hutchinson and Langeland, 2006). Control costs for L. microphyllum

range between $1000 per ha in easily accessed areas to $3,750 per ha in

more remote areas (2002 values; Masterson, 2007). We expect similar

control costs for L. japonicum.

Lygodium microphyllum and L. japonicum are controlled by timber and

agricultural managers (Carter-Finn et al., 2006; Ferriter, 2001;

Hutchinson and Langeland, 2006), and are classified as agricultural

weeds (Holm et al., 1979), which indicates they are harmful to wood

production systems. Lygodium japonicum forms mats that smother

shrubs and trees, and promotes fire in timber stands (Barnard and Loan,

N.D.; Ferriter, 2001; Miller, 2003). Anecdotal evidence and personal

communication with field biologists support these observations. For

example, L. microphyllum grows from drainage ditches in Florida onto

adjacent orchards (Nagid, 2008). Finally, Lygodium contaminates pine-

straw and hay, leading to regulatory action against these products

(ADAI, 2008) and potentially lower product value. Some interest exists

for developing a certification program for Lygodium-free pine-straw

(FFWCC, 2005).

Because Lygodium microphyllum and L. japonicum form impenetrable

vine blankets that are unsightly and relatively useless to wildlife, they

are likely harming outdoor recreational activities such as wildlife

viewing and hunting (Handley, 2008; Rowe, 2008). A member of the

Florida Cattlemen’s Association reported that Lygodium invades forests

that are adjacent to rangeland. These recreational activities are a

significant source of revenue. For example, in 2006 across the United

States, hunters spent $740 million on hunting leases, while wildlife

watchers spent $45.7 billion on travel and equipment (USFWS, 2006).

While these forests may or may not be used by cattle, the revenue

obtained from hunting leases is a significant source of income for the

Florida cattle industry (Handley, 2008).

Lygodium microphyllum and L. japonicum were assessed for their

impact potential using the set of questions listed in Appendix A. The

assessment indicated an overall moderate-high score of 3.0 and 3.2,

respectively (Table 1). Both species have well-documented

environmental effects.

We found less information about the impact and potential impact of L.

lexuosum than for the other two species, so the uncertainty was greater.

Lygodium flexuosum has never been taken out of its native range

(except see ARS, 2008b), where it lives in association with its

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coevolved pathogens and predators (e.g., Goolsby et al., 2003; Mound,

2002; Solis et al., 2005). Nevertheless, it is considered an agricultural

weed in its native range (Holm et al., 1979), where it reduces rice yields

(Roder et al., 1995a; Roder et al., 1995b), interferes with harvest

operations in rubber tree and oil palm plantations (PIC, 2008), and may

compete with tea plants for resources (Rajkhowa et al., 2005). In this

assessment, L. flexuosum obtained a moderate score of 2.1 (Table 1),

mostly due to impacts to production systems. Because its biology is

similar to that of the other two Lygodium species, L. flexuosum is likely

to similarly affect natural habitats and human environs if it establishes

in the United States. Lygodium flexuosum ranked among the top 25

species not yet in cultivation with the potential to significantly affect

agricultural and environmental ecosystems in the United States (Parker

et al., 2007).

6.3. Geographic Potential

As discussed above (sects. 5.1, 6.1) all three Lygodium species have

wide native distributions.

The distribution of L. microphyllum includes Plant Hardiness Zones 10-

13, and it may potentially occur in zone 9 based on country-province

level occurrences (e.g., Fujian, China; see Appendix A; Magarey et al.,

2008). In Florida, L. microphyllum is killed back to the ground by frost,

but it can regrow if its roots do not freeze (Pemberton and Ferriter,

1998). Because it grows in wet habitats, soil moisture protects the roots

somewhat from freezing temperatures. We think this fern could grow in

zone 9 (Pemberton and Ferriter, 1998). Thus, we think L. microphyllum

could establish in all of Florida, and coastal regions of Texas, Louisiana,

Alabama, and Mississippi. Approximately 9.9 percent of the total area

of the United States occurs in Plant Hardiness Zones 9-13 (PERAL,

2008).

The tropical and subtropical distribution of L. flexuosum in Southeast

Asia, suggests that it can also survive in Plant Hardiness Zones 9-13.

The distribution of L. japonicum indicates that it can survive in Plant

Hardiness Zones 7-13. We estimate that L. japonicum could establish in

about 39 percent of the United States (Appendix A). It may also survive

in zone 6, based on its presence in Korea (see Appendix A; ARS,

2008a), but this occurrence has not been confirmed, and we did not

consider it here. Experts recommend that gardeners in zone 6 mulch the

plant after the first frost (Ferriter, 2001), suggesting that it may not be

able to survive without human assistance in this zone.

6.4. Entry Potential

An international standard for pest risk assessment (ISPM #11)

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recommends that assessments consider pest entry potential (IPPC,

2007). Because L. microphyllum and L. japonicum are already in the

United States (Langeland and Burks, 1998), however, we do not need to

consider their entry potential (IPPC, 2007: see ISPM #11 sect. 2.2.1).

Overall, we estimate that the likelihood of entry for Lygodium

lexuosum to be high (0.55; Table 1) because it is used in basket

weaving (Anonymous, 2005) and is marketed on the internet

(Anonymous, 2008). Of less importance is its potential ability to

contaminate other pathways (Table 1).

Table 1. Summary of weed risk assessment results for three Lygodium species. See Appendix A

for more details. Numbers in parentheses are mean uncertainty levels for that risk element. The

scores for the four risk elements were not combined in any way; we used them to confirm the

preponderance of the descriptive evidence given above.

Risk Element (score range) Scores (mean uncertainty

)

L. microphyllum L. japonicum L. flexuosum

Establishment/Spread Potential (-23 – 29) 18 (0.9) 17 (1.0) 12 (1.3)

Potential Effects (1 – 4)

3.0 (1.5) 3.2 (1.5) 2.1 (2.1)

Environmental (0 – 1.2) 1.1 (1.3) 1.1 (1.4) 0.3 (2.5)

Human/Social (0 – 0.6) 0.3 (2.0) 0.3 (2.0) 0.0 (2.0)

Production (0 – 1.2) 0.6 (2.0) 0.8 (1.8) 0.8 (1.8)

Geographic Potential (0 – 1) 0.10 (1.2) 0.39 (1.3) 0.10 (1.0)

Entry Potential (0 – 1) N/A N/A 0.55 (1.7)

Negligible = 0, Low = 1, Moderate = 2, High = 3

The base score for potential effects is 1; the scores for the three sub-elements modify this value.

6.5. Weed Risk Potential

Lygodium microphyllum and L. japonicum have several traits that have

contributed to their ability to establish, naturalize, and spread in the

United States (sensu Richardson et al., 2000). Because they can form

dense vine blankets and alter fire regime, they have a variety of

environmental, aesthetic, and economic impacts. As such, they are

considered significant invaders. The results of this assessment are

consistent with another assessment that used the Australian weed risk

assessment system to evaluate their invasiveness (Gordon et al., 2008b).

Among a group of 205 species not in cultivation in the United States, L.

lexuosum was one of the top 25 weeds that pose the greatest risk to the

United States (Parker et al., 2007), supporting our recommendation

below. Due to limited information on L. flexuosum, its assessment had

higher uncertainty than that of the other two species (Table 1). Because

it shares many of the same traits as L. microphyllum and L. japonicum,

though, and because it is a “weed” in its native range, we expect it to

behave similarly in the United States.

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Lygodium microphyllum is in Florida, where it is a state noxious weed

(NRCS, 2008) and under widespread control by local, state, and federal

agencies (Hutchinson et al., 2006; Hutchinson and Langeland, 2006). It

is also regulated in Alabama where program managers are trying to

prevent its establishment in the state (ADAI, 2008). Lygodium

aponicum occurs throughout the southeastern United States, but it has

not yet reached the limit of its distribution and abundance. It also is a

state noxious weed in Florida and Alabama and controlled by a wide

variety of groups [e.g., Alabama (ADAI, 2008), Florida (Ferriter, 2001),

Georgia (Evans et al., 2005), and Texas (Korn et al., 2007; USDA-FS,

2007)].

Lygodium flexuosum is not in the United States. It meets the definition

of a noxious weed in the Plant Protection Act (7 U.S.C. § 7701-7786,

2000).

6.6. Recommendations

Based on their moderate to moderate high risk scores, we recommend

that Lygodium microphyllum (Cavanilles) R. Brown, Lygodium

aponicum (Thunb.) Sw., and Lygodium flexuosum (L.) Sw. be

considered for listing as Federal Noxious Weeds under the authority

granted to APHIS by the Plant Protection Act.

7. Contributors

USDA-APHIS-PPQ

Center for Plant Health Science and Technology

Plant Epidemiology and Risk Analysis Laboratory

Author: Anthony L. Koop (Botanist/Ecologist,)

Reviewers: Barney Caton (Ecologist), Larry Fowler (Botanist)

Editor: Ashley Jackson

USDA-APHIS-PPQ, Commodity Import Analysis & Operations

External reviewer: Polly Lehtonen (Senior Import Specialist)

External reviewer: Claudia Ferguson (Regulatory Policy

Specialist)

External reviewer: Christa Speekmann (Import Specialist – AAAS

Fellow)

USDA-APHIS-PPQ, Emergency and Domestic Programs

External reviewer: Al Tasker (National Weeds Program Manager)

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8. Figures

Figure 1. County level distribution of Lygodium microphyllum in the lower 48 states.

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Figure 2. County level distribution of Lygodium japonicum in the lower 48 states.

Note, it is also present in Hawaii and Puerto Rico which are not shown.

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9. References

7 U.S.C. § 7701-7786. 2000. Plant Protection Act, Title 7 United States Code § 7701-7786.

ADAI. 2008. Alabama Department of Agriculture and Industries: Administrative code. Alabama

Department of Agriculture and Industries (ADAI). Last accessed April 28, 2008,

http://www.alabamaadministrativecode.state.al.us/docs/agr/.

ALIPC. N.D. Alabama's ten worst invasive weeds. Alabama Invasive Plant Council (ALIPC),

AL, U.S.A. 2 pp.

Amoroso, C. B., and V. B. Amoroso. 1998. Spore culture studies on some economic ferns of

Mindanao, Philippines [Abstract]. Acta Horticulturae (461):231-235.

Anonymous. 2005. Jatujak weekend market. jj247.com, Bangkok, Thailand. Last accessed June

13, 2008, http://www.jj247.com/jatujak_about.html.

Anonymous. 2008. B & T world seeds, online catalogue. B & T World Seeds Company. Last

accessed June 13, 2008, http://www.b-and-t-world-seeds.com/index.htm.

APHIS. 2006. A guide to the listing process for federal noxious weeds. Animal and Plant Health

Inspection Service (APHIS), Plant Protection and Quarantine.

http://www.aphis.usda.gov/plant_health/plant_pest_info/weeds/downloads/listingguide.p

df.

ARS. 2008a. Germplasm Resources Information Network, online database. United States

Department of Agriculture, Agricultural Research Service (ARS), National Germplasm

Resources Laboratory. http://www.ars-grin.gov/cgi-bin/npgs/html/paper.pl. (Archived at

PERAL).

ARS. 2008b. Research project: Natural enemies of weeds which are endemic to Australia and

Southeast Asia, and invasive to the U.S.: 2006 annual report: 4d. progress report.

Agricultural Research Service (ARS), U.S.A. Last accessed June 13, 2008,

http://www.ars.usda.gov/research/projects/projects.htm?ACCN_NO=410266&showpars=

true&fy=2006.

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Appendix A.

Weed risk assessment of Lygodium microphyllum and L. japonicum. Note: The Plant Epidemiology and Risk Analysis Laboratory of APHIS

is currently revising its weed risk assessment process. Many of the questions used below come from or have been adapted from the Australian

weed risk assessment system (Pheloung et al., 1999) which has been tested over a wide range of geographies (e.g., Gordon et al., 2008a).

Most of the remaining questions originated from the current USDA weed risk assessment system (USDA, 2004), and the IPPC’s standard for

pest risk assessment (IPPC, 2007; ISPM #11). Both Lygodium spp. were analyzed using this new approach. For each species, the result or

letter response is shown, the associated score for that result, and the corresponding uncertainty level associated with the response. Generally,

an uncertainty level of negligible is appropriate when there can be no doubt from the literature or when the question was answered by an

expert. In contrast, high uncertainty corresponds to questions where the evidence is unclear or unavailable. Levels of low and moderate

uncertainty fall in between. The score for each of the four risk elements were summed and summarized in Table 1.

Lygodium microphyllum Lygodium japonicum Question

Result/Score/

Uncertainty

References & Notes Result/Score/

Uncertainty

References & Notes

Establishment/Spread Potential

1. Select one: (A) Introduced

elsewhere long ago (>75 years) but

not escaped (-4 pts); (B) Introduced

recently (<75 years) but not escaped

(-2); (C) Never introduced

elsewhere (0); (D) Escaped/Casual

(1); (E) Naturalized (2); (F)

Invasive (4).

f 4 negl Naturalized in Jamaica and

Guyana (Pemberton and Ferriter,

1998); however, in Florida, it is

an invasive that has rapidly

spread across the peninsula over

the last few decades (Hutchinson

et al., 2006; Pemberton and

Ferriter, 1998).

f 4 negl Naturalized in Puerto Rico

(Liogier and Martorell, 2000)

and Australia (Randall, 2007).

Invasive in the southeastern

United States (Ferriter, 2001)

and in Hawaii (Wilson, 2002).

2. Is the species highly

domesticated? (y=-3; n=0, ?=_)

n 0 mod There is no evidence that this

species has been domesticated.

n 0 mod Used as an ornamental

(DavesGarden, 2008), but no

evidence of domestication and

reduced invasiveness.

3. Adaptive potential. (A)

Individual plants demonstrated to

be phenotypically plastic/variable

when exposed to different

environmental conditions (2); (B)

Populations exhibit phenotypic or

a 2 mod One report states that it is

phenotypically plastic

(Hutchinson et al., 2006). Also, in

Florida, "it is common in bald

cypress stands, but also infests

pine flatwoods, wet prairies, saw

c 1 mod Tolerates sun to shade (FDEP,

N.D.). From habitat

descriptions, it appears to

invade moist to mesic uplands

(Ferriter, 2001).

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Lygodium microphyllum Lygodium japonicum Question

Result/Score/

Uncertainty

References & Notes Result/Score/

Uncertainty

References & Notes

genetic variation (among population

variation) (1); (C) Plants reported to

grow in diverse habitats or across a

wide/broad range of environmental

gradients (e.g., wet to dry, nutrient

poor to rich, sun to shade, fresh to

salt, hot to cold, etc.) (1); (D) Plants

are not known to be variable or

genetically diverse, or plants are

restricted to a narrow

environmental range (-1); (E)

Unknown (0 pts).

grass marshes, mangrove

communities, Everglades tree

islands, and disturbed areas"

(Pemberton and Ferriter, 1998).

4. [Answer only if question 1 is A,

B, or C]. Consider invasive/weed

status of congeners. (A) Plant has

no invasive/weedy congeners (0

pts); (B) Plant has a few (1-4)

invasive/weedy congeners (1); (C )

Plant has many (5 or more)

invasive/weedy congeners (2).

N/A N/A

5. Propagule pressure. Is the species

widely cultivated/popular/useful

such that its introduction and

cultivation will increase

establishment? (y=1, n=0, ?=_)

n 0 low Although this species was once

cultivated in North America

(Bailey and Bailey, 1976), there is

no evidence suggesting it is still

cultivated.

n 0 mod Only three nurseries listed

under Plant Information online,

one under Plant Find, and one

under Dave's Garden.

6. Shade tolerant at some stage of

life cycle? (y=1, n=0, ?=_)

y 1 negl Shade tolerance is believed to be

one of the main reasons it is

invasive in Florida (Volin et al.,

2004).

y 1 low Tolerates shade (FDEP, N.D.).

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Lygodium microphyllum Lygodium japonicum Question

Result/Score/

Uncertainty

References & Notes Result/Score/

Uncertainty

References & Notes

7. Climbing or smothering growth

habit? (y=1, n=0, ?=_)

y 1 negl (Pemberton and Ferriter, 1998) y 1 negl Plant is a vine (Langeland and

Burks, 1998; Mueller, 1983).

8. Aquatic? (y=5, n=0, ?=_) n 0 low Terrestrial (FNA Editorial

Committee, 1993).

n 0 low Terrestrial (Langeland and

Burks, 1998).

9. Grass? (y=1, n=0) n 0 negl Plant is a fern (NRCS, 2008). n 0 negl Not a grass (FNA Editorial

Committee, 1993).

10. Nitrogen-fixing woody plant?

(y=1, n=0, ?=_)

n 0 mod No evidence. n 0 mod No evidence.

11. Geophyte (herbaceous with

underground storage organs)? (y=1,

n=0, ?=_).

y 1 low Plants with rhizomes (Miller,

2003).

y 1 low Plants with rhizomes

(Hutchinson et al., 2006).

12. Produces viable seed or spores?

(y=1, ?=0, n=-1)

y 1 negl (Call et al., 2007) y 1 low Plants reproduce sexually via

spores (Ferriter, 2001).

13. Self-compatible or apomictic?

(y=1, ?=0, n=-1)

y 1 negl (Lott et al., 2003) y 1 negl Experiences intragametophytic

selfing (Lott et al., 2003)

14. Requires specialist pollinators?

(y=-1, n=0, ?=_)

n 0 negl Plant is a fern; does not use

pollinators (Lott et al., 2003).

n 0 negl Plant is a fern; does not use

pollinators (Lott et al., 2003)

15. Unpalatable to grazing animals?

(y=1, ?=0, n=-1)

? 0 high While one study reports cattle

eating an unknown Lygodium

species, this study is insufficient

to determine the overall

palatability of Lygodium (Dahlan

et al., 1988).

? 0 high While one study reports cattle

eating an unknown Lygodium

species, this study is

insufficient to determine the

overall palatability of

Lygodium (Dahlan et al., 1988).

16. Reproduction by vegetative

fragmentation? (y=1, ?=0, n=-1)

y 1 low Produces a short-creeping

rhizome (Weber, 2003).

y 1 low Produces a short-creeping

rhizome (Weber, 2003).

17. Minimum generative time (A) 1

year or less (1 pt), (B) 2 or 3 years

(0), (C) >3 years (-1pt); Unknown

(?)=_.

b 0 mod The gametophytic generation

becomes sexually mature in about

5 weeks (Lott et al., 2003). Plants

produce spores in 2-5 years

? high Unknown. No data available.

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

Rev. 005 May 12, 2009

Lygodium microphyllum Lygodium japonicum Question

Result/Score/

Uncertainty

References & Notes Result/Score/

Uncertainty

References & Notes

(Gardener and Marrinan, 2004)

18. Evidence that a persistent

propagule bank (e.g., seed bank) is

formed (>1yr)? (y=1, ?=0, n=-1)

y 1 mod Lygodium spp. spores can remain

viable for years (Hutchinson et

al., 2006).

y 1 mod Lygodium spp. spores can

remain viable for years

(Hutchinson et al., 2006).

"Spores of the Lygodium genus

have very thick walls, giving

these propagules long

environmental viability"

(Ferriter, 2001).

19. Well controlled by herbicides or

other cultural / management

techniques? (y=-1, ?=0, n=1)

n 1 mod "Many herbicides have activity

against Old World climbing fern,

however results are inconsistent.

Herbicide performance can be

affected by variables such as

weather conditions, site

conditions, application technique,

etc" (Hutchinson et al., 2006).

n 1 mod Although various herbicides

show activity against L.

japonicum, long-term control is

very variable, and overall

success is inconsistent. "All

Garlon 3A, Garlon 4, and

Pathfinder II plots had almost

100 percent regrowth within 8

months. The Rodeo plot had

approximately 5 percent

regrowth of L. japonicum and

growth of native species"

(Ferriter, 2001).

20. Tolerates/benefits from

mutilation, cultivation, or fire?

(y=1, ?=0, n=-1)

y 1 low Plant tolerates fires, returning to

pre-burn coverage within two

years (Hutchinson et al., 2006).

Furthermore, fire may help to

spread spores (Hutchinson and

Langeland, 2006).

y 1 mod Anecdotal comments and

observations suggest that it

tolerates fire (Munger, 2005).

21. Is resistant to some herbicides n 0 low No Lygodium species is listed as n 0 low No Lygodium species is listed

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

Rev. 005 May 12, 2009

Lygodium microphyllum Lygodium japonicum Question

Result/Score/

Uncertainty

References & Notes Result/Score/

Uncertainty

References & Notes

or has potential to acquire herbicide

resistance (e.g., related to

genetically modified crop it can

outcross to, congener of weeds

which have developed herbicide

resistance)? (y=1, n=0, ?=_)

having developed herbicide

resistance (Heap, 2008).

as having developed herbicide

resistance (Heap, 2008).

22. Hybridizes naturally? (y=1,

?=0, n=-1)

n -1 low There doesn't appear to be any

evidence of this species

hybridizing. A quick search

showed only one hybridization

event in Lygodium (Fay, 1973).

n -1 low There doesn't appear to be any

evidence of this species

hybridizing. A quick search

showed only one hybridization

event in Lygodium (Fay, 1973).

23. Propagules likely to be

dispersed unintentionally by

people? (y=1, ?=0, n=-1)

y 1 low Control operators may disperse

from site to site, but this may be

an insignificant risk compared to

the plant’s natural capacity to

spread (Hutchinson et al., 2006).

y 1 low Contaminates pine-straw and

equipment (Ferriter, 2001;

Miller, 2007). Spores

contaminate clothing (ISSG,

2008).

24. Propagules dispersed

intentionally by people? (y=1, ?=0,

n=-1)

y 1 low Even though it does not appear to

be cultivated still, as an

ornamental species it is likely to

be dispersed intentionally by

some (Bailey and Bailey, 1976).

y 1 negl Imported in the 1880s as an

ornamental (Pemberton and

Ferriter, 1998) and currently

featured in gardening books

(Bailey and Bailey, 1976; Page

and Olds, 2001). This species is

still cultivated, grown and sold

(DavesGarden, 2008).

25. Propagules adapted for either

wind, water, or animal (internal or

external) dispersal? (y=1, ?=0, n=-

y 1 negl Wind-dispersed (Wu et al., 2006). y 1 negl Spores are wind-dispersed

(Miller, 2007). Spores cling to

animal fur (ISSG, 2008).

26. Prolific seed/spore production y 1 negl As a fern, this question gets an y 1 low As a fern, this question gets an

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

Rev. 005 May 12, 2009

Lygodium microphyllum Lygodium japonicum Question

Result/Score/

Uncertainty

References & Notes Result/Score/

Uncertainty

References & Notes

(see scoring guide)? (y=1, ?=0, n=-

automatic yes. But one study

estimated about 15,000 spores per

square cm of fertile pinnae (Volin

et al., 2004).

automatic yes. One study

estimated bout 15,000 spores

per square cm of fertile pinnae

on L. microphyllum (Volin et

al., 2004); thus, L. japonicum is

probably very similar.

Impact Potential

27. Is there evidence or strong

reason to believe it impacts

ecosystem processes and system-

wide parameters that affect other

species (e.g., changes fire regime,

nutrient cycling, water availability,

community light levels, etc.)?

(y=0.2, n=0)

y 0.2 low Changes fire regime and

community light levels

(Hutchinson et al., 2006).

y 0.2 low Forms sun-blocking walls

(Langeland and Burks, 1998).

Alters fire regime (Ferriter,

2001).

28. Does it change community

structure by creating, modifying, or

eliminating vegetation layers?

(y=0.2, n=0)

y 0.2 low Creates an impermeable mat over

all vegetation, including the

canopy (Brandt and Black, 2001).

y 0.2 low Can form large vine mats in

native range (Ferriter, 2001).

Covers native plants in Florida

(ALIPC, N.D.; Langeland and

Burks, 1998).

29. Does the invasive/weedy taxon

change community composition by

reducing or eliminating native

species or promoting other invasive

species? (y=0.2, n=0)

y 0.2 low Reduces native species abundance

(Brandt and Black, 2001;

Pemberton, 2003).

y 0.2 low Smothers and displaces native

species (ALIPC, N.D.;

Langeland and Burks, 1998).

30. Does it impact or is it likely to

impact any particular native plant

species significantly more so than

others (e.g., through competition,

y 0.1 high L. microphyllum is a host for

Octothrips lygodii, which thus far

appears to only affect Lygodium

hosts (Mound, 2002). L.

y 0.1 high L. japonicum is a host for

Octothrips lygodii, which thus

far appears to only affect

Lygodium hosts (Mound,

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

Rev. 005 May 12, 2009

Lygodium microphyllum Lygodium japonicum Question

Result/Score/

Uncertainty

References & Notes Result/Score/

Uncertainty

References & Notes

parasitism, hybridization, or

alternate host for pest or disease)?

(y=0.1, n=0)

microphyllum in the U.S. may

provide a pathway for the entry

and establishment of the thrips,

which could impact the native L.

palmatum.

2002). L. japonicum in the U.S.

may provide a pathway for the

entry and establishment of the

thrips, which could impact the

native L. palmatum.

31. Consider the potential

distribution of the invasive plant in

the United States and the potential

habitats it may invade. Is it likely to

affect any federal Threatened and

Endangered plant species? (y=0.1,

n=0)

y 0.1 low

Cucurbita okeechobeensis

(Hutchinson et al., 2006).

y 0.1 mod Is a threat to at least three

Florida T&E species (Ferriter,

2001). It may also threaten

U.S.-listed Threatened and

Endangered species such as

Thalictrum cooleyi, which

occurs in similar mesic habitats

as Lygodium (CPC, 2008)

32. Consider the potential

distribution of the invasive plant in

the United States and the potential

habitats it may invade. Is it likely to

affect any globally outstanding

ecoregions as defined by Ricketts et

al. (1999)? (y=0.1, n=0)

y 0.1 low It has invaded southern and

central Florida (Hutchinson et al.,

2006).

y 0.1 low It has invaded the southeastern

United States (NRCS, 2008),

which contain several globally

outstanding ecoregions

(Ricketts et al., 1999).

33. Allelopathic? (y=0.1, n=0) n 0 mod There is no evidence that it is

allelopathic.

n 0 mod There is no evidence that it is

allelopathic.

34. Is this plant directly

targeted/controlled by managers in

conservation areas? (y=0.2, n=0)

y 0.2 negl (Hutchinson et al., 2006) y 0.2 negl (Ferriter, 2001)

35. Produces a human allergen or

toxin, or is otherwise physically

harmful? (y=0.1, n=0)

n 0 mod No evidence. n 0 mod No evidence.

36. Produces spines, thorns, burrs, n 0 mod No evidence. n 0 mod No evidence.

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

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Lygodium microphyllum Lygodium japonicum Question

Result/Score/

Uncertainty

References & Notes Result/Score/

Uncertainty

References & Notes

or other undesirable trait (e.g., foul

smell, stains property)? (y=0.1,

n=0)

37. Does it hinder or otherwise

affect processes and aspects

generally deemed important for

human civilization or safety (e.g.,

vines on power lines, shrubs or

trees on utility right-of-ways,

growth in urban structures,

destabilizes coastal dunes)? (y=0.1,

n=0)

y 0.1 mod It is being managed and cleared

on a major highway in Florida

(Florida Turnpike) (Hutchinson et

al., 2006).

y 0.1 mod "Lygodium [japonicum] then

occurred in about 10 locations

along the park drive and in an

equal number of locations

along powerline rights-of-way"

(Ferriter, 2001). Moderate

uncertainty because there was

no mention of degree of

impact.

38. Changes or limits recreational

use of an area (e.g., hinders

navigation in bodies of water,

hunting/fishing, impedes scenic

vistas)? (y=0.1, n=0)

y 0.1 mod May impact hunting leases on

private lands (Handley, 2008;

Rowe, 2008). "Lygodium poses an

unknown economic threat to the

tourism industry through its

degradation of natural resources

in Florida's parks and recreation

areas" (Ferriter, 2001).

y 0.1 low "Access to lands is denied"

(ALIPC, N.D.). May impact

hunting leases on private lands

(Handley, 2008; Rowe, 2008).

"Lygodium poses an unknown

economic threat to the tourism

industry through its degradation

of natural resources in Florida's

parks and recreation areas"

(Ferriter, 2001).

39. Outcompetes, replaces or

otherwise affects desirable plants

and vegetation (e.g., gardens,

lawns, street trees)? (y=0.1, n=0 )

n 0 mod No evidence. y 0.1 high "In 2000, plants were found in

Kaneohe, volunteering in

gardens among cultivated and

native plants" (Wilson, 2002).

High uncertainty because there

is no real evidence that it

impacts these features.

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

Rev. 005 May 12, 2009

Lygodium microphyllum Lygodium japonicum Question

Result/Score/

Uncertainty

References & Notes Result/Score/

Uncertainty

References & Notes

40. Is this plant widely

targeted/controlled by citizens or

other groups or agencies in

urban/suburban areas? (y=0.1, n=0)

y 0.1 mod Along major highways in Florida

(Hutchinson et al., 2006).

n 0 mod No evidence.

41. Reduces crop/product yield

(e.g., by parasitism, competition, or

by harboring other pests)? (y=0.2,

n=0)

n 0 mod No evidence. y 0.2 mod "L. japonicum poses a serious

economic risk to pine

plantations through its spread

and intensification of fire"

(Ferriter, 2001). "Scattered in

open timber stands and

plantations, but can increase in

cover to form mats, smothering

shrubs and trees." (Miller,

2003). Present in timber stands

(Barnard and Loan, N.D.).

42. Lowers commodity value (e.g.,

by increasing costs of production,

lowering market prices, or other)?

(y=0.2, n=0)

y 0.2 mod L. microphyllum grows in wet

ditches along orchards (e.g.,

citrus); it can grow over and onto

the trees, thereby requiring

treatment (Nagid, 2008).

y 0.2 low Treatment of L. japonicum in

pine plantations will increase

control costs, particularly to

avoid contaminated pine straw

(Nagid, 2008). There is a

movement to certify plantations

that are Lygodium free

(FFWCC, 2005).

43. Results in a loss of markets

(foreign or domestic) due to the

presence of a new quarantine pest?

(y=0.2, n=0)

y 0.2 mod L. microphyllum is a state noxious

weed in Alabama where it is

regulated, including in nursery

stock and hay (ADAI, 2008).

y 0.2 low Regulated in Florida and

Alabama (NRCS, 2008).

Because it contaminates pine-

straw bales (Ferriter, 2001), it

may result in a loss of domestic

and or foreign markets, or at

least requirement of risk

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

Rev. 005 May 12, 2009

Lygodium microphyllum Lygodium japonicum Question

Result/Score/

Uncertainty

References & Notes Result/Score/

Uncertainty

References & Notes

management programs (e.g.

Clark, 2005).

44. Reduces the quality or

availability of irrigation, or strongly

competes with plants for water?

(y=0.1, n=0).

n 0 mod No evidence. n 0 mod No evidence.

45. Toxic to animals, including

livestock/range animals and poultry

(y=0.1, n=0)?

n 0 mod No evidence (CU, 2008). n 0 mod No evidence (CU, 2008).

46. Host for recognized pests and

pathogens? (y=0.1, n=0, ?=_)

? high Unknown. ? high Unknown.

47. Parasitic? (y=0.1, n=0) n 0 low Not described as a parasitic plant

(FNA Editorial Committee,

1993).

n 0 low Not described as a parasitic

plant (FNA Editorial

Committee, 1993).

48. Is this plant directly controlled

or managed in some fashion in any

production system (e.g., agriculture,

forestry, horticulture, aquaculture,

etc.)? (y=0.2, n=0)

y 0.2 mod See Table 4: "Land area infested

with and treated for invasive

species by professional managers"

(Carter-Finn et al., 2006).

Assigning moderate uncertainty

because the reference was not

directly about Lygodium.

y 0.2 mod "Foresters in north central

Florida report that neither

prescribed burns nor

application of herbicide

containing the active ingredient

2,4-D, or combinations, were

effective for controlling it in

pine plantations" (Ferriter,

2001). Assigned moderate

uncertainty, because it doesn't

appear to be a problem all the

time, at least during dry springs

(Ferriter, 2001).

Entry Potential

49. Plant already here? (y=1, n=0). y 1 negl (Wunderlin and Hansen, 2008) y 1 negl (Miller, 1995)

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

Rev. 005 May 12, 2009

Lygodium microphyllum Lygodium japonicum Question

Result/Score/

Uncertainty

References & Notes Result/Score/

Uncertainty

References & Notes

STOP IF YES

50. Plant proposed for entry, or

entry is imminent? (y=1, n=0)

STOP IF YES

N/A N/A

51. Plant under cultivation or

sold/traded elsewhere? (y=0.25,

n=0) [Skip #54 if yes. Skip #53 if

no.]

N/A N/A

52. Plant currently marketed on the

internet or traded by growers

elsewhere? (enter 2 for yes, or 1 for

no)

N/A N/A

53. Plant not under cultivation but

deemed important? (y=0.05, n=0)

N/A Used in its native range

(Hutchinson et al., 2006).

N/A

54. Natural dispersal? (y=.05, n=0) N/A N/A

55. Plant present in Canada,

Mexico, Central America, the

Caribbean or China? Note doubles

likelihood of all contaminating

pathways (enter 2 for yes, or 1 for

no)

N/A (Hutchinson et al., 2006) N/A

56. Q56 (contaminants of fruits and

vegetables for consumption)?

(y=0.01, n=0)

N/A N/A

57. Q37 (contaminants in plants for

planting, including aquarium plants

and products)? (y=0.04, n=0)

N/A N/A

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

Rev. 005 May 12, 2009

Lygodium microphyllum Lygodium japonicum Question

Result/Score/

Uncertainty

References & Notes Result/Score/

Uncertainty

References & Notes

58. Bird seed, or seeds for planting

(contaminants in grain, flower seed

packets, etc.)? (y=0.04, n=0)

N/A N/A

59. Ballast water? (y=0.03, n=0) N/A N/A

60. Military vehicles or other

equipment? (y=0.02, n=0)

N/A N/A

61. Imported landscape products

(e.g., pine-straw, hydro mulch, etc.)

(y=0.02, n=0)?

N/A N/A

62. Other (specify) (A) 0.01, (B)

0.02, (C ) 0.03, (D) 0.04

N/A N/A

Geographic Potential (USDA

Plant Hardiness Zones)

Zone 1 (0.056) n 0 low n 0 low

Zone 2 (0.037) n 0 low n 0 low

Zone 3 (0.058) n 0 low n 0 low

Zone 4 (0.129) n 0 low n 0 low

Zone 5 (0.133) n 0 low n 0 mod

Zone 6 (0.192) n 0 low n 0 high Korea (ARS, 2008a).

Gardeners in Zone 6 are

recommended to mulch after

first frost (Ferriter, 2001).

Because it may be unlikely to

survive without human

assistance, answering no, but

with high uncertainty.

Numbers in parentheses represent the proportion of the United States (lower 48 states, Alaska, Hawaii, and Puerto Rico) in that plant hardiness zone. All numbers sum to

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

Rev. 005 May 12, 2009

Lygodium microphyllum Lygodium japonicum Question

Result/Score/

Uncertainty

References & Notes Result/Score/

Uncertainty

References & Notes

Zone 7 (0.152) n 0 low y 0.152 mod Korea (ARS, 2008a). Reported

to be in Korea (ARS, 2008a),

but no documentation in which

location. Zone 7 is the warmest

zone in Korea (Magarey et al.,

2008).

Zone 8 (0.143) n 0 low y 0.143 low Western Japan (ARS, 2008a);

southern Arkansas (NRCS,

2008); (DavesGarden, 2008)

Zone 9 (0.089) y 0.089 mod South Africa, China (ARS,

2008a). Orlando, Florida

(Pemberton, 2003)

y 0.089 low Taiwan (NTU, 2008);

(DavesGarden, 2008)

Zone 10 (0.009) y 0.009 low Angola, Mozambique, Zambia,

Zimbabwe, China, Florida (ARS,

2008a)

y 0.009 low Taiwan (NTU, 2008);

(DavesGarden, 2008)

Zone 11 (0.001) y 0.001 low Angola, Mozambique, Zambia,

Zimbabwe, Florida (ARS, 2008a)

y 0.001 low Taiwan (NTU, 2008);

(DavesGarden, 2008)

Zone 12 (0.0003) y 0.0003 low Australia, Tanzania (ARS, 2008a) y 0.0003 low Hawaii (Wilson, 2002);

Malaysia, Papua New Guinea

(ARS, 2008a)

Zone 13 (0.0004) y 0.0004 mod Kenya, Uganda (ARS, 2008a) y 0.0004 low Hawaii (Wilson, 2002);

Malaysia, Papua New Guinea

(ARS, 2008a)

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

Rev. 005 May 12, 2009

Appendix B.

Weed risk assessment of Lygodium flexuosum. See Appendix A table heading for additional information.

Lygodium flexuosum Question

Result/Score/

Uncertainty

References & Notes

Establishment/Spread Potential

1. Select one: (A) Introduced elsewhere long ago (>75 years)

but not escaped (-4 pts); (B) Introduced recently (<75 years)

but not escaped (-2); (C) Never introduced elsewhere (0); (D)

Escaped/Casual (1); (E) Naturalized (2); (F) Invasive (4).

c 0 mod No evidence that it has been moved outside of its

naturalized range, other than for research under

quarantine conditions (ARS, 2008b).

2. Is the species highly domesticated? (y=-3; n=0, ?=_) n 0 mod No evidence.

3. Adaptive potential. (A) Individual plants demonstrated to be

phenotypically plastic/variable when exposed to different

environmental conditions (2); (B) Populations exhibit

phenotypic or genetic variation (among population variation)

(1); (C) Plants reported to grow in diverse habitats or across a

wide/broad range of environmental gradients (e.g., wet to dry,

nutrient poor to rich, sun to shade, fresh to salt, hot to cold,

etc.) (1); (D) Plants are not known to be variable or genetically

diverse, or plants are restricted to a narrow environmental

range (-1); (E) Unknown (0 pts).

c 1 low "Climbs trees and scrambles in open places in rainforest

and on cliffs and banks" (DEWR, 2008). Grows in

deciduous forests and mixed forests (SFD, 2008).

4. [Answer only if question 1 is A, B, or C]. Consider

invasive/weed status of congeners. (A) Plant has no

invasive/weedy congeners (0 pts); (B) Plant has a few (1-4)

invasive/weedy congeners (1); (C ) Plant has many (5 or more)

invasive/weedy congeners (2).

b 1 negl Lygodium japonicum and L. microphyllum are invasive

weeds in the United States (Ferriter, 2001). L.

circinnatum and L. polymorphum are considered weeds

by others (Holm et al., 1979; Randall, 2008), but

evidence is less clear.

5. Propagule pressure. Is the species widely

cultivated/popular/useful such that its introduction and

cultivation will increase establishment? (y=1, n=0, ?=_)

n 0 low No nurseries appear to currently carry it (query: Plant

Find and Plant Information Online). Basic horticultural

information unavailable (query: Dave’s Garden).

6. Shade tolerant at some stage of life cycle? (y=1, n=0, ?=_) y 1 low Requires partial to full shade (DavesGarden, 2008).

Found in mature shaded areas in plantations (PIC, 2008).

7. Climbing or smothering growth habit? (y=1, n=0, ?=_) y 1 negl (DEWR, 2008)

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Rev. 005 May 12, 2009

Lygodium flexuosum Question

Result/Score/

Uncertainty

References & Notes

8. Aquatic? (y=5, n=0, ?=_) n 0 negl (DEWR, 2008)

9. Grass? (y=1, n=0) n 0 negl Plant is a terrestrial fern.

10. Nitrogen-fixing woody plant? (y=1, n=0, ?=_) n 0 mod No evidence that it fixes nitrogen.

11. Geophyte (herbaceous with underground storage organs)?

(y=1, n=0, ?=_).

y 1 low The genus Lygodium produces rhizomes (Mueller,

1982).

12. Produces viable seed or spores? (y=1, ?=0, n=-1) y 1 negl Spores have a high rate of germination (94%-95%)

(Amoroso and Amoroso, 1998).

13. Self-compatible or apomictic? (y=1, ?=0, n=-1) y 1 low Capable of intragametophytic selfing (Lal and Roy,

1983).

14. Requires specialist pollinators? (y=-1, n=0, ?=_) n 0 negl Plant is a fern.

15. Unpalatable to grazing animals? (y=1, ?=0, n=-1) ? 0 high In oil and rubber plantations in Malaysia, it is grazed on

last, after all other palatable species (Wahab, 2001).

16. Reproduction by vegetative fragmentation? (y=1, ?=0, n=-

y 1 high Plants produce rhizomes (DEWR, 2008), which are

assumed to result in vegetative reproduction.

17. Minimum generative time (A) 1 year or less (1 pt), (B) 2 or

3 years (0), (C) >3 years (-1pt); Unknown (?)=_.

b 0 mod Plants produce spores in 2-5 years (Gardener and

Marrinan, 2004). Spores producing the gametophyte

generation germinate within a few days (Trivedi and

Kher, 1976).

18. Evidence that a persistent propagule bank (e.g., seed bank)

is formed (>1yr)? (y=1, ?=0, n=-1)

y 1 mod Lygodium spp. spores can remain viable for years

(Hutchinson et al., 2006). "Spores of the Lygodium

genus have very thick walls, giving these propagules

long environmental viability" (Ferriter, 2001). Fern

spores can remain dormant for years (Banks, 1999).

Moderate uncertainty because decision was based on

genus level information.

19. Well controlled by herbicides or other cultural /

management techniques? (y=-1, ?=0, n=1)

? 0 high Unknown, but paraquat is specifically recommended for

ferns (PIC, 2008).

20. Tolerates/benefits from mutilation, cultivation or fire? (y=1, ? 0 high

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

Rev. 005 May 12, 2009

Lygodium flexuosum Question

Result/Score/

Uncertainty

References & Notes

?=0, n=-1)

21. Is resistant to some herbicides or has potential to acquire

herbicide resistance (e.g., related to genetically modified crop it

can outcross to, congener of weeds which have developed

herbicide resistance)? (y=1, n=0, ?=_)

n 0 low No Lygodium species is listed as having developed

herbicide resistance (Heap, 2008).

22. Hybridizes naturally? (y=1, ?=0, n=-1) n -1 low There doesn't appear to be any evidence of this species

hybridizing. A quick search showed only 1 hybridization

event in Lygodium (Fay, 1973).

23. Propagules likely to be dispersed unintentionally by

people? (y=1, ?=0, n=-1)

y 1 high L. microphyllum and L. japonicum can be dispersed

unintentionally by people (Hutchinson et al., 2006;

Miller, 2007). It is reasonable to assume the same will be

true for L. flexuosum.

24. Propagules dispersed intentionally by people? (y=1, ?=0,

n=-1)

y 1 mod Marketed on the internet (Anonymous, 2008).

25. Propagules adapted for either wind, water, or animal

(internal or external) dispersal? (y=1, ?=0, n=-1)

y 1 negl Ferns produce wind-dispersed spores.

26. Prolific seed/spore production (see scoring guide)? (y=1,

?=0, n=-1)

y 1 negl As a fern, this question gets an automatic yes. One study

estimated bout 15,000 spores per square cm of fertile

pinnae on L. microphyllum (Volin et al., 2004); L.

flexuosum is probably very similar.

Impact Potential

27. Is there evidence or strong reason to believe it impacts

ecosystem processes and system-wide parameters that affect

other species (e.g., changes fire regime, nutrient cycling, water

availability, community light levels, etc.)? (y=0.2, n=0)

? high No information available from native or introduced

range outside of U.S. However, L. microphyllum, which

has a similar growth form, changes fire regime and

community light levels in Florida (Hutchinson et al.,

2006).

28. Does it change community structure by creating,

modifying, or eliminating vegetation layers? (y=0.2, n=0)

? high No information available from native or introduced

range outside of U.S. However, L. microphyllum, which

has a similar growth form, creates an impermeable mat

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

Rev. 005 May 12, 2009

Lygodium flexuosum Question

Result/Score/

Uncertainty

References & Notes

over all vegetation, including the canopy (Brandt and

Black, 2001).

29. Does the invasive/weedy taxon change community

composition by reducing or eliminating native species or

promoting other invasive species? (y=0.2, n=0)

? high No information available from native or introduced

range outside of U.S. However, L. microphyllum, which

has a similar growth form, reduces native species

abundance (Brandt and Black, 2001; Pemberton, 2003)

30. Does it impact or is it likely to impact any particular native

plant species significantly more so than others (e.g., through

competition, parasitism, hybridization, or alternate host for pest

or disease)? (y=0.1, n=0)

y 0.1 high L. flexuosum is a host for Octothrips lygodii, which thus

far, appears to only affect Lygodium hosts (Mound,

2002). Establishment of L. flexuosum in the U.S. may

provide a pathway for the entry and establishment of the

thrips, which could impact the native L. palmatum.

31. Consider the potential distribution of the invasive plant in

the United States and the potential habitats it may invade. Is it

likely to affect any federal Threatened and Endangered plant

species? (y=0.1, n=0)

y 0.1 mod It may threaten US listed Threatened and Endangered

species such as Thalictrum cooleyi which occurs in

similar mesic habitats as Lygodium (CPC, 2008).

32. Consider the potential distribution of the invasive plant in

the United States and the potential habitats it may invade. Is it

likely to affect any globally outstanding ecoregions as defined

by Ricketts et al. (1999)? (y=0.1, n=0)

y 0.1 low Based upon its potential distribution in plant hardiness

zones 9 and higher, it can impact the southeastern U.S.

which contains several globally outstanding ecoregions

(Ricketts et al., 1999).

33. Allelopathic? (y=0.1, n=0) n 0 mod No evidence.

34. Is this plant directly targeted/controlled by managers in

conservation areas? (y=0.2, n=0)

n 0 high No evidence that it has been introduced elsewhere and

subject to control.

35. Produces a human allergen or toxin, or is otherwise

physically harmful? (y=0.1, n=0)

n 0 mod No evidence.

36. Produces spines, thorns, burrs, or other undesirable trait

(e.g., foul smell, stains property)? (y=0.1, n=0)

n 0 mod No evidence.

37. Does it hinder or otherwise affect processes and aspects

generally deemed important for human civilization or safety

(e.g., vines on power lines, shrubs or trees on utility right-of-

n 0 mod No evidence.

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

Rev. 005 May 12, 2009

Lygodium flexuosum Question

Result/Score/

Uncertainty

References & Notes

ways, growth in urban structures, destabilizes coastal dunes)?

(y=0.1, n=0)

38. Changes or limits recreational use of an area (e.g., hinders

navigation in bodies of water, hunting/fishing, impedes scenic

vistas)? (y=0.1, n=0)

n 0 mod No evidence.

39. Outcompetes, replaces or otherwise affects desirable plants

and vegetation (e.g., gardens, lawns, street trees)? (y=0.1, n=0 )

n 0 mod No evidence.

40. Is this plant widely targeted/controlled by citizens or other

groups or agencies in urban/suburban areas? (y=0.1, n=0)

n 0 mod No evidence.

41. Reduces crop/product yield (e.g., by parasitism,

competition, or by harboring other pests)? (y=0.2, n=0)

y 0.2 low Considered a primary constraint to rice production and

reduces rice yield (Roder et al., 1995b; Roder et al.,

1997).

42. Lowers commodity value (e.g., by increasing costs of

production, lowering market prices, or other)? (y=0.2, n=0)

y 0.2 low Weeding in rice fields increases cost of production;

weeding is labor intensive (Roder et al., 1995b; Roder et

al., 1997). Interferes with harvest in tree plantations

(PIC, 2008)

43. Results in a loss of markets (foreign or domestic) due to the

presence of a new quarantine pest? (y=0.2, n=0)

y 0.2 high Unknown. But L. japonicum and L. microphyllum are

regulated in Florida and Alabama (NRCS, 2008).

Because L. japonicum contaminates pine straw bales

(Ferriter, 2001), it may result in a loss of domestic and/or

foreign markets, or at least requirement of risk

management programs (e.g., Clark, 2005).

44. Reduces the quality or availability of irrigation, or strongly

competes with plants for water? (y=0.1, n=0).

? high

45. Toxic to animals, including livestock/range animals and

poultry (y=0.1, n=0)?

n 0 mod No evidence (CU, 2008).

46. Host for recognized pests and pathogens? (y=0.1, n=0, ?=_) ? high

47. Parasitic? (y=0.1, n=0) n 0 low Not described as a parasitic plant.

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

Rev. 005 May 12, 2009

Lygodium flexuosum Question

Result/Score/

Uncertainty

References & Notes

48. Is this plant directly controlled or managed in some fashion

in any production system (e.g., agriculture, forestry,

horticulture, aquaculture, etc.)? (y=0.2, n=0)

y 0.2 negl Controlled in rice fields (Roder et al., 1995b; Roder et

al., 1997) and tree plantations (PIC, 2008). It, among

other weeds, is controlled in tea plantations, where it is

considered a high to significant weed (Rajkhowa et al.,

2005).

Entry Potential

49. Plant already here? (y=1, n=0). STOP IF YES n 0 low Not listed in the USDA Plants Database. Imported by

USDA-ARS to study impact of potential biological

control agents for Lygodium microphyllum (ARS,

2008b).

50. Plant proposed for entry, or entry is imminent? (y=1, n=0)

STOP IF YES

n 0 low

51. Plant under cultivation or sold/traded elsewhere? (y=0.25,

n=0) [Skip #54 if yes. Skip #53 if no.]

y 0.5 low Listed in a seed company catalogue, but may not be

readily available (Anonymous, 2008). Plant used in

handcrafts (Anonymous, 2005).

52. Plant currently marketed on the internet or traded by

growers elsewhere? (enter 2 for yes, or 1 for no)

2 negl (Anonymous, 2008).

53. Plant not under cultivation but deemed important? (y=0.05,

n=0)

N/A

54. Natural dispersal? (y=.05, n=0) n 0 negl Not present in surrounding regions.

55. Plant present in Canada, Mexico, Central America, the

Caribbean or China. Note doubles likelihood of all

contaminating pathways? (enter 2 for yes, or 1 for no)

1 negl Not present in surrounding regions.

56. Q56 (contaminants of fruits and vegetables for

consumption)? (y=0.01, n=0)

y 0.01 mod "Creepers like Mikania [and Lygodium flexuosum]

contaminate plucked shoots" of tea in India (Rajkhowa et

al., 2005). It is likely spores may be present on the

contaminants.

57. Q37 (contaminants in plants for planting, including

aquarium plants and products)? (y=0.04, n=0)

? 0 high Unknown, but spores could readily contaminate any Q37

material.

WRA for Lygodium microphyllum, L. japonicum, & L. flexuosum.

Rev. 005 May 12, 2009

Lygodium flexuosum Question

Result/Score/

Uncertainty

References & Notes

58. Bird seed, or seeds for planting (contaminants in grain,

flower seed packets, etc.)? (y=0.04, n=0)

? 0 high Unknown, but spores could readily contaminate this

material.

59. Ballast water? (y=0.03, n=0) n 0 mod No evidence, but considered unlikely.

60. Military vehicles or other equipment? (y=0.02, n=0) y 0.02 high Unknown for L. flexuosum, but L. japonicum

contaminates equipment (Miller, 2007).

61. Imported landscape products (e.g., pine-straw, hydro

mulch, etc.) (y=0.02, n=0)?

y 0.02 high Unknown for L. flexuosum, but "L. japonicum has also

been identified as a contaminant in pine straw bales"

(Clark, 2005; Ferriter, 2001).

62. Other (specify) (A) 0.01, (B) 0.02, (C ) 0.03, (D) 0.04 ? 0.00 high

Geographic Potential (USDA Plant Hardiness Zones)

Zone 1 (0.056) n 0 low

Zone 2 (0.037) n 0 low

Zone 3 (0.058) n 0 low

Zone 4 (0.129) n 0 low

Zone 5 (0.133) n 0 low

Zone 6 (0.192) n 0 low

Zone 7 (0.152) n 0 low

Zone 8 (0.143) n 0 high

Zone 9 (0.089) y 0.089 mod

Zone 10 (0.009) y 0.009 low

Temperate and subtropical China: Guangdong, Guangzi,

and Guizhou provinces (ARS, 2008a).

Zone 11 (0.001) y 0.001 negl In northern Australia (DEWR, 2008).

Zone 12 (0.0003) y 0.0003 negl In northern Australia (DEWR, 2008).

Zone 13 (0.0004) y 0.0004 negl Sir Lanka (ARS, 2008a); Malaysia (Lim et al., 2001).

Numbers in parentheses are the proportion of area of the United States (lower 48 states, Alaska, Hawaii, and Puerto Rico) in that plant hardiness zone. All numbers sum

to 1.