Weed Risk Assessment for

United States Gymnocoronis spilanthoides (D. Don ex Department of Hook. & Arn.) DC. (Asteraceae) – Agriculture Senegal tea plant Animal and Plant Health Inspection Service

August 1, 2012

Version 1

Top left: Upright stems of Gymnocoronis spilanthoides (source: HaWalter Stahel, Environmental Bay of Plenty, Bugwood.org). Bottom left: Horizontal stems of G. spilanthoides (source: Robert Vidéki, Doronicum Kft., Bugwood.org). Right: Gymnocoronis spilanthoides infestation along a stream in Te Kowhai, Waikato, New Zealand (source: P. Mabin, http://www.weedbusters.co.nz/).

Agency Contact:

Plant Epidemiology and Risk Analysis Laboratory Center for Plant Health Science and Technology

Plant Protection and Quarantine Animal and Plant Health Inspection Service United States Department of Agriculture 1730 Varsity Drive, Suite 300 Raleigh, NC 27606 Weed Risk Assessment for Gymnocoronis spilanthoides

Introduction Plant Protection and Quarantine (PPQ) regulates noxious weeds under the authority of the Plant Protection Act (7 U.S.C. § 7701-7786, 2000) and the Federal Seed Act (7 U.S.C. § 1581-1610, 1939). A noxious weed is defined as “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). We use weed risk assessment (WRA) - specifically, the PPQ WRA model (Koop et al., 2012) - to evaluate the risk potential of plants, including those newly detected in the United States, those proposed for import, and those emerging as weeds elsewhere in the world.

Because the PPQ WRA model is geographically and climatically neutral, it can be used to evaluate the baseline invasive/weed potential of any plant species for the entire United States or for any area within it. As part of this analysis, we use a stochastic simulation to evaluate how much the uncertainty associated with the analysis affects the model outcomes. We also use GIS overlays to evaluate those areas of the United States that may be suitable for the establishment of the plant. For more information on the PPQ WRA process, please refer to the document, Background information on the PPQ Weed Risk Assessment, which is available upon request.

Gymnocoronis spilanthoides (D. Don ex Hook. & Arn.) DC.– Senegal tea plant Species Family: Asteraceae Information Initiation: On January 12, 2012, Al Tasker (PPQ, National Weeds Program Manager) requested that the PERAL Weed Team evaluate the risk potential of Gymnocoronis spilanthoides (Tasker, 2012). Of particular concern was determining whether this species is cultivated in the United States. Foreign distribution: This species is native to South America, in Argentina, Bolivia, Brazil, Paraguay, Peru, and Uruguay (GBIF, 2012; NGRP, 2012). Some sources, however, indicate it is native from Mexico to Argentina (e.g., Parsons and Cuthbertson, 2001). It has been introduced to and become naturalized in China (Tian-Gang and Yan, 2007), Hungary

(Torok et al., 2003), Japan (Kadono, 2004), Taiwan (Jung et al., 2009), and in Australia and New Zealand (NGRP, 2012). It is imported by the aquarium trade in European countries (Brunel, 2009). This species appears on the alert list of the European Plant Protection Organization (Hussner, 2012). U.S. distribution and status: Gymnocoronis spilanthoides is present in the U.S. aquarium trade, just as in other countries (Champion et al., 2010; Kadono, 2004; Parsons and Cuthbertson, 2001). An internet search

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showed it is sold online in the United States (e.g., Anonymous, 2012; ExtraPlant, 2012), but it is not known to be naturalized here (Kartesz, 2012; NRCS, 2012). The Oregon Department of Agriculture lists G. spilanthoides as a target for early detection and rapid response (ODA, 2007). WRA area1: Entire United States, including territories

1. Gymnocoronis spilanthoides analysis Establishment/Spread As mentioned above, G. spilanthoides has naturalized and spread in other Potential regions of the world. Native to the Neotropics, this herbaceous perennial is a semiaquatic plant that establishes in wetlands and the edges of bodies of water (CRC, 2003; Parsons and Cuthbertson, 2001). We treated this species as an aquatic plant because stems are hollow, inflated, and buoyant, and typically form dense floating mats that extend into deeper water (CRC, 2003; Parsons and Cuthbertson, 2001). Stem fragments readily root and give rise to new plants. Plant propagules (stem fragments and seeds) are dispersed by water and on mud that attaches to animals (CABI, 2012; Parsons and Cuthbertson, 2001). Gymnocoronis spilanthoides is also dispersed unintentionally by people when they dispose aquarium plants in the environment or move contaminated equipment (e.g., boats) (CRC, 2003). Also contributing to this species’ risk score is its tolerance to mutilation and persistence in soil seed banks (Panetta, 2010; Parsons and Cuthbertson, 2001). There was an average amount of uncertainty associated with this risk element. Three questions could not be answered due to a lack of information. Risk score = 16 Uncertainty index = 0.17

Impact Potential Gymnocoronis spilanthoides is considered a weed and is managed in natural and anthropogenic systems (CRC, 2003). It is a noxious weed in Australia and New Zealand (DAF, 2012; MPI, 2012; Parsons and Cuthbertson, 2001) and targeted for eradication in cities (Hussey and Lloyd, 2002). Dense mats of G. spilanthoides can alter community structure and exclude native species (CRC, 2003; Timmins and Mackenzie, 1995; WMC, 2012). Large infestations can block waterways, with consequent impacts on flooding, irrigation, and recreational access (CRC, 2003; MPI, 2012; WMC, 2012). One source called it an ecosystem transformer2 (Torok et al., 2003) but we found no evidence to support this. Large-scale decomposition of this vegetation might affect water quality (ISSG, 2012; WMC, 2012). Although we found no evidence of impact in production systems, it may also be managed in these systems (Parsons and Cuthbertson, 2001; WMC, 2012).

1 “WRA area” is the area in relation to which the weed risk assessment is conducted [definition modified from that for “PRA area” (IPPC, 2012). 2 Senso Richardson et. al. (2000).

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This risk element had a moderate amount of uncertainty. Risk score = 3.4 Uncertainty index = 0.22

Geographic Potential Based on three climatic variables, we estimate that about 23 percent of the United States is suitable for the establishment of G. spilanthoides (Fig. 1). This predicted distribution is based on the species’ known distribution elsewhere in the world and includes point-referenced localities and areas of occurrence. The map for G. spilanthoides represents the joint distribution of Plant Hardiness Zones 7-13, areas with 20-100+ inches of annual precipitation, and the following Köppen-Geiger climate classes: tropical rainforest, tropical savanna, humid subtropical, marine west coast, humid continental warm summers, and humid continental cool summers. Because this tropical species occurs in Hungary (CISEH, 2012; Torok et al., 2003), we assumed it can occur in humid continental, warm summer climate classes (Peel et al., 2007). Despite finding some evidence of presence in a Mediterranean climate (a home garden in Perth, Australia) (Hussey and Lloyd, 2002), we did not consider that because home gardens might create artificial environments, and it was not clear whether G. spilanthoides could survive in Mediterranean climates on its own.

The area in Fig. 1 likely represents a conservative estimate as it uses three climatic variables to predict the area of the United States that is suitable for establishment of the species. Other environmental variables, such as soil and habitat type, may further limit the areas in which this species is likely to establish. Gymnocoronis spilanthoides grows in areas of wet marshy soils and in areas with still or very slowly moving waters (CABI, 2012; Parsons and Cuthbertson, 2001). It seems unlikely to establish or be problematic in any other types of habitats.

Entry Potential We did not assess G. spilanthoides’ entry potential because this species is already present in the United States under cultivation (Anonymous, 2012; ExtraPlant, 2012).

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Figure 1. Predicted distribution of Gymnocoronis spilanthoides in the United States. Map insets for Alaska, Hawaii, and Puerto Rico are not to scale.

2. Results and Conclusion Model Probabilities: P(Major Invader) = 84.3% P(Minor Invader) = 15.1% P(Non-Invader) = 0.6%

Risk Result = High Risk Secondary Screening = Not Applicable

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Figure 2. Gymnocoronis spilanthoides risk score (black box) relative to the risk scores of species used to develop and validate the PPQ WRA model (other symbols). See Appendix A for the complete assessment.

Figure 3. Monte Carlo simulation results (N=5,000) for uncertainty around the risk scores for Gymnocoronis spilanthoidesa.

a The blue “+” symbol represents the medians of the simulated outcomes. The smallest box contains 50 percent of the outcomes, the second 95 percent, and the largest 99 percent.

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3. Discussion The result of the weed risk assessment for G. spilanthoides is High Risk. With an 84.3 percent probability of becoming a major-invader in the United States, this species scored relatively high (Fig. 2). Despite the uncertainty associated with this assessment, our result was robust (Fig. 3). Thus, even if some of the answers in the assessment were to change based on new evidence, the result of the assessment is likely to still be High Risk. Gymnocoronis spilanthoides has been evaluated with other weed risk assessment models, and in all cases it has ranked relatively high (Champion and Clayton, 2001; Parker et al., 2007; Pheloung, 1995; Weber and Panetta, 2006). Notably, we found very few ecological studies on G. spilanthoides, particularly on its impacts. Many of the resources we found referenced the weed management guide published by the Cooperative Research Centre of Australia (CRC, 2003). Additional studies or primary reports of its impacts would be valuable.

Managers should be aware that G. spilanthoides is in the aquarium trade (Champion et al., 2010; Kadono, 2004; Parsons and Cuthbertson, 2001) and is cultivated in the United States (Anonymous, 2012; ExtraPlant, 2012). Although some infestations in Australia resulted from careless disposal of aquarium plants, some infestations started as deliberate releases in public land for harvest by aquarists (CRC, 2003). Controlling G. spilanthoides has been challenging because herbicides are sometimes ineffective when plants are growing in standing water. Furthermore, any kind of mechanical control that fragments plants may result in new plants establishing downstream (ISSG, 2012).

4. Literature Cited 7 U.S.C. § 1581-1610. 1939. The Federal Seed Act, Title 7 United States Code § 1581-1610. 7 U.S.C. § 7701-7786. 2000. Plant Protection Act, Title 7 United States Code § 7701-7786. Anonymous. 2012. Snowball (Water snowball) new! Pond Megastore. Last accessed July 10, 2012, https://www.pondmegastore.com/shop/product.php?productid=16842. Brunel, S. 2009. Pathway analysis: aquatic plants imported in 10 EPPO countries. EPPO Bulletin 39(2):201-213. CABI. 2012. Invasive Species Compendium, Online Database. CAB International (CABI). http://www.cabi.org/cpc/. (Archived at PERAL). Champion, P. D., and J. S. Clayton. 2001. A weed risk assessment for aquatic weeds in New Zealand. Pages 194-202 in R. H. Groves, F. D. Panetta, and J. G. Virtue, (eds.). Weed Risk Assessment. CSIRO, Collingwood, Australia. Champion, P. D., J. S. Clayton, and D. E. Hofstra. 2010. Nipping aquatic plant invasions in the bud: Weed risk assessment and the trade. Hydrobiologia 656(1):167-172. CISEH. 2012. Online Database. The University of Georgia - Center for Invasive Species and Ecosystem Health (CISEH). http://www.invasive.org/index.cfm.

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(Archived at PERAL). CRC. 2003. Weed management guide: Senegal tea plant - Gymnocoronis spilanthoides. Cooperative Research Centre (CRC), Australia. 6 pp. DAF. 2012. Senegal tea (Gymnocoronis spilanthoides). Government of Western Australia; Department of Agriculture and Food (DAF), Western Australia. Last accessed June 28, 2012, http://agspsrv95.agric.wa.gov.au/dps/version02/01_plantview.asp?page=1& contentID=58&p1=gymnocoronis. DPI. 2012. Victorian resources online - Invasive Plants. Department of Primary Industries (DPI). Last accessed June 29, 2012, http://www.dpi.vic.gov.au/DPI/Vro/vrosite.nsf/pages/lwm_pest_plants. ExtraPlant. 2012. Aquarium plant mailorder company. ExtraPlant Florida. Last accessed June 29, 2012, http://www.extraplant.us/. Gao, H., and Z. Chen. 2011. Gymnocoronis: A new naturalized genus in Eastern China [abstract]. Journal of Zhejiang A&F University 28(6):992-994. GBIF. 2012. GBIF, Online Database. Global Biodiversity Information Facility (GBIF). http://data.gbif.org/welcome.htm. (Archived at PERAL). Heap, I. 2012. The international survey of herbicide resistant weeds. Weed Science Society of America. www.weedscience.com. (Archived at PERAL). Heenan, P. B., P. J. de Lange, D. S. Glenny, I. Breitwieser, P. J. Brownsey, and C. C. Ogle. 1999. Checklist of dicotyledons, gymnosperms, and pteridophytes naturalised or casual in New Zealand: additional records 1997-1998. New Zealand Journal of Botany 37:629-642. Heide-Jorgensen, H. S. 2008. Parasitic Flowering Plants. Brill, Leiden, The Netherlands. 438 pp. Howell, C. J., and J. W. D. Sawyer. 2006. New Zealand naturalised vascular plant checklist. New Zealand Plant Conservation Network,, Wellington, New Zealand. 60 pp. Hussey, B. M. J., and S. G. Lloyd. 2002. Western weeds: Additions, deletions and name changes. Plant Protection Society of Western Australia, Perth, Australia. 8 pp. Hussner, A. 2012. Alien aquatic plant species in European countries. Weed Research:1-10. IPPC. 2012. International standards for phytosanitary measures (ISPM#5): Glossary of phytosanitary terms. Secretariat of the International Plant Protection Convention (IPPC), Food and Agriculture Organization of the United Nations, Rome. 38 pp. ISSG. 2012. Global Invasive Species Database. The World Conservation Union (IUCN), Invasive Species Specialist Group (ISSG). Last accessed June 2012, http://www.issg.org/database/welcome/. Jung, M.-J., T.-C. Hsu, S.-W. Chung, and C.-I. Peng. 2009. Three newly naturalized Asteraceae plants in Taiwan. Taiwania 54(1):76-81. Kadono, Y. 2004. Alien aquatic plants naturalized in Japan: History and present status. Global Environmental Research 8(2):163-169. Kartesz, J. 2012. The Biota of North America Program (BONAP). North American Plant Atlas. http://www.bonap.org/MapSwitchboard.html. (Archived at PERAL). Koop, A., L. Fowler, L. Newton, and B. Caton. 2012. Development and validation of a weed screening tool for the United States. Biological Invasions 14(2):273- 294. Krombholz, P. 1997. The Krib: Aquaria and tropical fish web site. Erik Olson. Last Ver. 1 August 1, 2012 7

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accessed July 30, 2012, http://www.thekrib.com/. Mabberley, D. J. 2008. Mabberley's Plant-Book: A Portable Dictionary of Plants, their Classification and Uses (3rd edition). Cambridge University Press, New York, USA. 1021 pp. Malacalza, N. H., M. A. Caccavari, G. Fagúndez, and C. E. Lupano. 2005. Unifloral honeys of the province of Buenos Aires, Argentine. Journal of the Science of Food and Agriculture 85(8):1389-1396. Martin, P. G., and J. M. Dowd. 1990. A protein sequence study of the dicotyledons and its relevance to the evolution of the legumes and nitrogen fixation. Australian Systematic Botany 3:91-100. Martin, T. G., S. Campbell, and S. Grounds. 2006. Weeds of Australian rangelands. The Rangeland Journal 28(1):3-26. MPI. 2012. Senegal tea: Gymnocoronis spilanthoides. Ministry of Primary Industries (MPI), Wellington, New Zealand. Last accessed June 12, 2012, http://www.biosecurity.govt.nz/pests/senegal-tea. NGRP. 2012. Germplasm Resources Information Network (GRIN). United States Department of Agriculture, Agricultural Research Service, National Genetic Resources Program (NGRP). http://www.ars-grin.gov/cgi- bin/npgs/html/index.pl?language=en. (Archived at PERAL). Nickrent, D. 2009. Parasitic plant classification. Southern Illinois University Carbondale, Carbondale, IL, U.S.A. Last accessed June 12, 2009, http://www.parasiticplants.siu.edu/ListParasites.html. Nobuyuki, O. 2005. Seed set and germination characteristics of an alien aquatic plant, Gymnocoronis spilanthoides DC. Japanese Journal of Conservation Ecology 10(2):113-118. NRCS. 2012. The PLANTS Database. United States Department of Agriculture, Natural Resources Conservation Service (NRCS), The National Plant Data Center. http://plants.usda.gov/cgi_bin/. (Archived at PERAL). ODA. 2007. Western US Invasive Plant EDRR Weed ID Guide. Oregon Department of Agriculture (ODA), and US Department of Agriculture, Salem, OR, U.S.A. 96 pp. Panetta, F. D. 2010. Seed persistence of the invasive aquatic plant, Gymnocoronis spilanthoides (Asteraceae). Australian Journal of Botany 57(8):670-674. Parker, C., B. P. Caton, and L. Fowler. 2007. Ranking nonindigenous weed species by their potential to invade the United States. Weed Science 55:386-397. Parsons, W. T., and E. G. Cuthbertson. 2001. Noxious weeds of Australia (2nd edition). CSIRO Publishing, Collingwood, Victoria, Australia. 698 pp. Peel, M. C., B. L. Finlayson, and T. A. McMahon. 2007. Updated world map of the Köppen-Geiger climate classification. Hydrology and Earth Systems Sciences 11:1633-1644. Pheloung, P. 1995. Determining the weed potential of new plant introductions to Australia. Agriculture Protection Board, Western Australia. 36 pp. Randall, J. M. 2007. The Introduced Flora of Australia and its Weed Status. CRC for Australian Weed Management, Department of Agriculture and Food, Western Australia, Australia. 528 pp. Richardson, D. M., P. Pyšek, M. Rejmanek, M. G. Barbour, F. D. Panetta, and C. J. West. 2000. Naturalization and invasion of alien plants: Concepts and definitions. Diversity and Distributions 6:93-107. Ricketts, T. H., E. Dinerstein, D. M. Olson, C. J. Loucks, W. Elchbaum, D. DellaSala, K. Kavanagh, P. Hedao, P. T. Hurley, K. M. Carney, R. Abell, and S. Walters. 1999. Terrestrial Ecoregions of North America: A Ver. 1 August 1, 2012 8

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Conservation Assessment. Island Press, Washington D.C. 485 pp. Tasker, A. 2012. Gymnocoronis spilanthoides - for Round 2? Personal communication to A. Koop on January 12, 2012, from Al Tasker, PPQ National Weeds Program Manager. Tian-Gang, G., and L. Yan. 2007. Gymnocoronis, a new naturalized genus of the tribe Eupatorieae, Asteraceae in China. Journal of Systematics and Evolution 45(3):329-332. Timmins, S. M., and I. W. Mackenzie. 1995. Weeds in New Zealand protected natural areas database. New Zealand Department of Conservation, Wellington, New Zealand. 287 pp. Torok, K., Z. Botta-Dukat, I. Dancza, I. Nemeth, J. Kiss, B. Mihaly, and D. Magyar. 2003. Invasion gateways and corridors in the Carpathian Basin: Biological invasions in Hungary. Biological Invasions 5:349-356. Vivian-Smith, G., D. Hinchliffe, and J. Weber. 2005. Fecundity and germination of the invasive aquatic plant, Senegal tea (Gymnocoronis spilanthoides (D.Don) DC.) [abstract]. Plant Protection Quarterly 20(4):145-147. Weber, E. 2003. Invasive Plant Species of the World: A Reference Guide to Environmental Weeds. CABI Publishing, Wallingford, UK. 548 pp. Weber, J., and F. D. Panetta. 2006. Weed risk assessment of the DEH Alert List and other non-native plant species. Pages 739-742 in C. Preston, J. H. Watts, and N. D. Crossman, (eds.). Proceedings of the Fifteenth Australian Weeds Conference: Managing Weeds in a Changing Climate. Council of Australasian Weed Societies, Adelaide Convention Centre, Adelaide, South Australia. WMC. 2012. Weedbusters detailed information sheet: Gymnocoronis spilthanoides. The Weedbusters Management Committee (WMC). Last accessed June 28, 2012, http://www.weedbusters.co.nz/weed_info/detail.asp?WeedID=11.

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Appendix A. Weed risk assessment for Gymnocoronis spilanthoides (D. Don ex Hook. & Arn.) DC. (Asteraceae). The following information was obtained from the species’ risk assessment, which was conducted using Microsoft Excel. The information shown in this appendix was modified to fit on the page. The original Excel file, the full questions, and the guidance to answer the questions are available upon request.

Question ID Answer - Score Notes (and references) Uncertainty ESTABLISHMENT/SPREAD POTENTIAL ES-1 (Status/invasiveness outside f - negl 5 Introduced to Australia in the mid-1970s and documented as its native range) naturalized by 1980 (Parsons and Cuthbertson, 2001). Fully naturalized in New Zealand (Howell and Sawyer, 2006). Recently naturalized in China (Tian-Gang and Yan, 2007) and Taiwan (Jung et al., 2009). In Japan, plants readily escape cultivation and establish in the surrounding environment; this species is now rapidly expanding its distribution (Kadono, 2004). Invasive (Category 5A) in Australia (Randall, 2007). Species is native to South America and possibly Central America as well (GBIF, 2012; NGRP, 2012; Parsons and Cuthbertson, 2001). It is being imported as an aquarium plant into EPPO countries, but not yet known to have naturalized (Brunel, 2009), with the exception of Hungary where it is considered invasive (definition consistent with our usage in this risk element (Torok et al., 2003). The weight of the evidence indicates this species has naturalized elsewhere and is capable of spreading. Alternate answers for the Monte Carlo simulation are both "e". ES-2 (Is the species highly n - low 0 No evidence. Species is cultivated in the aquarium trade domesticated) (Champion et al., 2010; ExtraPlant, 2012; Kadono, 2004; Parsons and Cuthbertson, 2001). However, there is no evidence that it has been bred to reduce traits associated with weed potential. ES-3 (Weedy congeners) n - negl 0 No evidence. There are only 2-3 species in this genus (Mabberley, 2008). A literature search did not indicate any other species in this genus as weedy; consequently, using "negl" uncertainty. ES-4 (Shade tolerant at some y - high 1 Answering “yes” because one source indicates it can tolerate stage of its life cycle) shade (Timmins and Mackenzie, 1995). However, using "high" uncertainty because this was an anecdotal piece of information that was not supported with any kind of documentation, but the source is reputable. ES-5 (Climbing or smothering n - negl 0 Plant is not a vine. Plant is a perennial herb that forms growth form) rounded bushes (Parsons and Cuthbertson, 2001). Stems are erect, or prostrate and scrambling (Parsons and Cuthbertson, 2001). ES-6 (Forms dense thickets) y - negl 2 Forms dense infestations (Weber, 2003). Forms dense mats (WMC, 2012). Picture available (see title page of WRA) showing a dense infestation along a stream contributes to “negl” uncertainty (WMC, 2012). ES-7 (Aquatic) y - negl 1 A freshwater or marsh emergent perennial (Parsons and Cuthbertson, 2001). Plant stems are erect at first, but later become prostrate and scrambling (Parsons and Cuthbertson, 2001). Stems are hollow, inflated, and buoyant and typically form floating mats that extend into deeper water from the

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Question ID Answer - Score Notes (and references) Uncertainty edges of water bodies (CRC, 2003; Parsons and Cuthbertson, 2001). Seedlings can grow underwater and later emerge (Parsons and Cuthbertson, 2001). A perennial aquatic herb (MPI, 2012). ES-8 (Grass) n - negl 0 Plant is not a grass; it is in the family Asteraceae (NGRP, 2012) ES-9 (Nitrogen-fixing woody n - negl 0 No evidence. Plant is not in a family known to fix nitrogen plant) (Martin and Dowd, 1990). ES-10 (Does it produce viable y - negl 1 Reproduces by seed (Parsons and Cuthbertson, 2001; WMC, seeds or spores) 2012). ES-11 (Self-compatible or ? - max 0 Unknown. apomictic) ES-12 (Requires special n - low 0 The flowers attract many insects including butterflies as pollinators) pollinators (Kadono, 2004). It has been introduced as a butterfly-attracting plant (Panetta, 2010). Pollen grains have been detected in honey (Malacalza et al., 2005). Enough circumstantial evidence indicates it does not require specialist pollinators. Furthermore, it is able to produce seeds (Parsons and Cuthbertson, 2001; WMC, 2012) where it has been introduced, suggesting it most likely does not need a specialist pollinator. ES-13 (Minimum generation b - high 0 No information that addresses minimum generation time. time) Plant is a perennial herb (Parsons and Cuthbertson, 2001) that reproduces from seed and vegetative fragments. In the winter, this species dies back to the ground but regrows at the beginning of the next growing season (Parsons and Cuthbertson, 2001). Based on how quickly it is reported to grow in aquaria (Krombholz, 1997), it is possible it may experience multiple generations per year under natural conditions, if plant stems are frequently mutilated. It is highly unlikely to require 4 years or more as an herb. Answering "b" with "high" uncertainty. Alternate answers for the Monte Carlo Simulation are "c" and "a". ES-14 (Prolific reproduction) n - negl -1 The following data come from a study of the reproductive potential of G. spilanthoides plants in two urban populations in Australia (Vivian-Smith et al., 2005). Researchers observed (not directly measured) about 0-100 and 0-10 inflorescences (capitula) per square meter. They measured 11.8 and 4.3 seeds produced per capitulum. They obtained germination rates of up to 83 percent (Vivian-Smith et al., 2005). Thus, assuming maximum flowering, seed set, and germination, plants can produce 980 (100 X 11.8 X 0.83) seeds per square meter. This is much lower than the 5,000 viable seeds per square meter threshold for prolific reproduction. Other reports, whether citing Vivian-Smith et al. (2005) or based on their own observations, indicate seed production is not very high (CRC, 2003; WMC, 2012). Answering with “negl” uncertainty. ES-15 (Propagules likely to be y - negl 1 Spread by boats, fishing equipment, and dumping of aquaria dispersed unintentionally by plants (Timmins and Mackenzie, 1995; WMC, 2012). Stem people) fragments can be spread by transport and machinery such as boats, trailers, lawnmowers, etc., but it is likely, however, that one of the main reasons for its introduction to new areas

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Question ID Answer - Score Notes (and references) Uncertainty may be from the disposal of aquarium plants in freshwater (CRC, 2003). Established at a rubbish dump in New Zealand (Heenan et al., 1999). ES-16 (Propagules likely to ? - max 0 Unknown. In the abstract of one report, the authors state that disperse in trade as contaminants it enters China by cargo (Gao and Chen, 2011); it is not clear or hitchhikers) from this if the authors meant it can be a contaminant of cargo or whether the plant is a commodity itself. ES-17 (Number of natural 2 0 Seed description for questions ES-17a-17e: Seed is about 0.5 dispersal vectors) mm in diameter, ribbed, and without a crown or pappus (Parsons and Cuthbertson, 2001). Seeds (achenes) are 0.8 mm to 1.2 mm long and 0.5 mm wide (Panetta, 2010). ES-17a (Wind dispersal) n - negl Seeds are too heavy for wind dispersal (Parsons and Cuthbertson, 2001). Seeds drop near the parent plant (CRC, 2003). ES-17b (Water dispersal) y - negl Seeds and stem fragments disperse in streamflow; stems are buoyant (Parsons and Cuthbertson, 2001). Water dispersed (CABI, 2012). ES-17c (Bird dispersal) n - mod No evidence of bird dispersal or that bird dispersal would be a significant mechanism for spread. ES-17d (Animal external y - low Seeds are dispersed in mud sticking to animal hooves dispersal) (Parsons and Cuthbertson, 2001). Stem fragments can be spread on the hooves of animals (WMC, 2012). ES-17e (Animal internal n - mod No evidence of internal animal dispersal or that this would be dispersal) a significant mechanism for its dispersal. ES-18 (Evidence that a persistent y - negl 1 A three-year seed burial experiment showed that seeds retain (>1yr) propagule bank (seed their viability over long periods if light is excluded; the bank) is formed) author believes that seeds could easily remain viable in the soil for many years (Panetta, 2010). Because it was the entire focus of the study to evaluate long-term seed persistence, answering “yes” with "negl" uncertainty. ES-19 (Tolerates/benefits from y - negl 1 Stem fragments readily form adventitious roots from the mutilation, cultivation or fire) nodes, leading to formation of new colonies (Parsons and Cuthbertson, 2001). A weed management guide for Australia asks citizens not to try to manage it themselves, as the plant can spread very easily from dislodged stem fragments (CRC, 2003). ES-20 (Is resistant to some ? - max Unknown. Gymnocoronis spilanthoides is very hard to kill herbicides or has the potential to and herbicides are effective only on the upper parts of the become resistant) plant, as submerged parts are not killed and can regrow (CRC, 2003). "Following repeated efforts, glyphosate has proven to be ineffective in south Queensland, and it shows some resistance to the most commonly approved aquatic herbicides (Sainty and Jacobs, 2003)." (CABI, 2012). Not listed by Heap (2012) as resistant. It is not clear from the available evidence whether this species is resistant to herbicides. Because this is an aquatic environmental weed (and not an agricultural weed that would be under lots of selective pressure to develop herbicide resistance), it seems more likely that the "evidence" for resistance is really evidence for tolerance. However, answering "unknown", nevertheless. ES-21 (Number of cold hardiness 7 0 zones suitable for its survival)

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Weed Risk Assessment for Gymnocoronis spilanthoides

Question ID Answer - Score Notes (and references) Uncertainty ES-22 (Number of climate types 6 2 suitable for its survival) ES-23 (Number of precipitation 9 1 bands suitable for its survival) IMPACT POTENTIAL General Impacts Imp-G1 (Allelopathic) n - mod 0 No evidence. Imp-G2 (Parasitic) n - negl 0 No evidence. The Asteraceae family is not known to contain parasitic plants (Heide-Jorgensen, 2008; Nickrent, 2009). Impacts to Natural Systems Imp-N1 (Change ecosystem ? - max Unknown. Classified as a transformer species in Hungary, processes and parameters that but a detailed description or explanation is lacking (Torok et affect other species) al., 2003). Rotting vegetation ruins water quality (WMC, 2012). "If large-scale die offs of this species occurs, water quality may decline" (ISSG, 2012). Answering unknown because the evidence is partially speculative and not convincing. Imp-N2 (Change community y - mod 0.2 Forms mats over shallow and deep water (CRC, 2003; WMC, structure) 2012). Formation of vegetative mats in an aquatic ecosystem that is normally more open is a change in the distribution of plant layers in this community. Answering “yes” but using "mod" uncertainty because this was not directly stated in the literature. Imp-N3 (Change community y - negl 0.2 "Senegal tea grows very quickly, and is known to rapidly composition) cover water bodies with a floating mat, excluding other plants and the animals that rely on them " (MPI, 2012). Degrades natural wetlands by displacing native plants (CABI, 2012; WMC, 2012). Considered a threat to Australian rangeland biodiversity (Martin et al., 2006). Excludes other plants (Timmins and Mackenzie, 1995). Using “negl” uncertainty, particularly after seeing a picture of a dense infestation in New Zealand (WMC, 2012). Imp-N4 (Is it likely to affect y - low 0.1 Because it excludes other plants and animals (CRC, 2003; federal Threatened and ISSG, 2012), it is likely to affect T&E species. Endangered species) Imp-N5 (Is it likely to affect any y - mod 0.1 Some authors believe this plant poses a significant threat to globally outstanding ecoregions) the health of wetland ecosystems (ISSG, 2012). Given the impacts to community diversity and structure described above, it seems likely this species could affect ecoregions. There are numerous wetland and aquatic habitats (e.g., the Florida Everglades) in globally outstanding ecoregions (Ricketts et al., 1999) where this species could establish. Imp-N6 (Weed status in natural c - negl 0.6 Weed of the natural environment in Australia (Randall, systems) 2007). Considered a weed of rangelands (Martin et al., 2006); however, we are listing this evidence here and not in P6 because ultimately the concern about this species was about its impact to natural diversity and not yield. This plant is controlled in natural systems in Australia (CRC, 2003). Weed survey crews routinely monitor for this plant (CRC, 2003). Control methodologies are described in various references (CABI, 2012; CRC, 2003; Parsons and Cuthbertson, 2001). Alternate answers for the Monte Carlo simulation are both "b".

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Weed Risk Assessment for Gymnocoronis spilanthoides

Question ID Answer - Score Notes (and references) Uncertainty Impact to Anthropogenic Systems (cities, suburbs, roadways) Imp-A1 (Impacts human y - negl 0.1 "The effects of flooding are made much worse because property, processes, civilization, infestations block drainage channels….navigation may also or safety) be affected" (MPI, 2012). Has caused flooding in New Zealand because it blocks drainage channels and streams (CABI, 2012). Causes flooding (WMC, 2012). Infestations block drainage channels (ISSG, 2012). Imp-A2 (Changes or limits y - negl 0.1 The long branches produce a tangled web of vegetative recreational use of an area) material that stretches across the water surface and quickly impedes waterflow, navigation, and recreation (Parsons and Cuthbertson, 2001). "Recreational activities, irrigation and navigation may also be affected" (MPI, 2012). Can obstruct waterways (Timmins and Mackenzie, 1995). Detracts from the environmental value of wetlands, natural beauty, and recreational value (CRC, 2003). Recreational activities and navigation may be impacted (ISSG, 2012). Imp-A3 (Outcompetes, replaces, n - mod 0 No evidence. or otherwise affects desirable plants and vegetation) Imp-A4 (Weed status in c - negl 0.4 This plant is considered a weed of anthropogenic areas anthropogenic systems) because of flooding and clogging of drainage ways (CRC, 2003). Some hobbyists think this plant is somewhat weedy in even in aquaria (Krombholz, 1997). The CRC Weed Management reference describes specific control strategies that relate to control in drainage systems: first plants are sprayed with herbicides, then a week later management crews remove all plant material and silt up to a meter deep (CRC, 2003). This species was cultivated in Perth, but now all known plants have been eradicated since it is a state noxious weed (Hussey and Lloyd, 2002). Controlled by Manukau City Council in New Zealand (Timmins and Mackenzie, 1995). Subject to eradication in at least two urban creeks in Australia (Vivian-Smith et al., 2005). Alternate answers for the Monte Carlo simulation are both "b". Impact to Production Systems (agriculture, nurseries, forest plantations, orchards, etc.) Imp-P1 (Reduces crop/product n - low 0 No evidence. Another WRA rated this as low likelihood but yield) did not provide any supporting documentation (DPI, 2012). Imp-P2 (Lowers commodity n - low 0 No evidence. Another WRA rated this as low likelihood but value) did not provide any supporting documentation (DPI, 2012). Imp-P3 (Is it likely to impact n - mod 0 No evidence. Regulated as a noxious weed in Australia and trade) New Zealand (DAF, 2012; MPI, 2012; Parsons and Cuthbertson, 2001). Illegal to import and cultivate in Australia and New Zealand (CABI, 2012). However, there is no clear evidence it is likely to follow a trade pathway (see ES-16 above). Imp-P4 (Reduces the quality or n - high 0 The long branches produce a tangled web of vegetative availability of irrigation, or material that stretches across the water surface and quickly strongly competes with plants for impedes waterflow (Parsons and Cuthbertson, 2001). The water) floating mats of vegetation it creates may affect irrigation (MPI, 2012). Irrigation may be impacted (ISSG, 2012). This "evidence" seems more speculative than anything else. Answering "no" because of this, but also because there isn't much evidence it is a significant weed of productions

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Weed Risk Assessment for Gymnocoronis spilanthoides

Question ID Answer - Score Notes (and references) Uncertainty systems. Imp-P5 (Toxic to animals, n - low 0 No evidence. It is eaten by animal stock and has been known including livestock/range animals to provide grazing during winter in wet areas (ISSG, 2012). and poultry) Imp-P6 (Weed status in c - high 0.6 Present in a farm dam in Australia; initial control was not production systems) successful (Parsons and Cuthbertson, 2001). The Weedbusters website provides some suggestions for control, including a statement suggesting that sites infested with this species not be grazed so that animal stock does not release seeds and stem fragments (WMC, 2012). This suggests there is at least interest in limiting its further spread in these systems. Answering c, but with "high" uncertainty due to the quality of the evidence. Alternate answers for the Monte Carlo simulation are "b" and "a". GEOGRAPHIC POTENTIAL Unless otherwise stated all geographic information used below was obtained from GBIF (2012). PS = point-source data (latitude/longitude geo-referenced data points, or other). Occ = presence within a region. Plant cold hardiness zones Geo-Z1 (Zone 1) n - negl N/A No evidence. Geo-Z2 (Zone 2) n - negl N/A No evidence. Geo-Z3 (Zone 3) n - negl N/A No evidence. Geo-Z4 (Zone 4) n - negl N/A No evidence. Geo-Z5 (Zone 5) n - negl N/A No evidence. Geo-Z6 (Zone 6) n - low N/A No evidence. Geo-Z7 (Zone 7) y - low N/A PS: Kanto, Japan; Occ: Keszthely, Hungary (CISEH, 2012). Geo-Z8 (Zone 8) y - low N/A PS: Gaoting Town, China (Gao and Chen, 2011); New Zealand (1 point on edge; GBIF, 2012); Osaka prefecture, Japan (Nobuyuki, 2005). Geo-Z9 (Zone 9) y - negl N/A PS: Australia (1 point inside, several on edge), New Zealand Geo-Z10 (Zone 10) y - negl N/A PS: Australia and Argentina. Frost tolerant (CABI, 2012), if under water (Timmins and Mackenzie, 1995). Geo-Z11 (Zone 11) y - negl N/A PS: Paraguay. Geo-Z12 (Zone 12) y - negl N/A PS: Peru and Bolivia. Geo-Z13 (Zone 13) y - low N/A PS: Brazil (1 point). Köppen-Geiger climate classes Geo-C1 (Tropical rainforest) y - low N/A PS: Bolivia, Brazil. Geo-C2 (Tropical savanna) y - negl N/A PS: Peru, Bolivia. Geo-C3 (Steppe) n - low N/A No evidence. Geo-C4 (Desert) n - negl N/A No evidence. Geo-C5 (Mediterranean) ? - max N/A Located in a home garden in Perth Australia (GBIF, 2012). Answering as "unknown" because it is within a cultivated landscape which typically ameliorates environmental conditions. How for our map of geographic potential, we assumed that Mediterranean climates are not suitable for this species. Geo-C6 (Humid subtropical) y - negl N/A PS: Kanto, Japan; Argentina (GBIF, 2012). Occ: Kyushu, Japan (Kadono, 2004). Geo-C7 (Marine west coast) y - negl N/A PS: Australia, New Zealand. Geo-C8 (Humid cont. warm y - high N/A Because this tropical species occurs in Hungary under humid sum.) continental cool summers (CISEH, 2012; Torok et al., 2003), it seems very likely it will also be able to occur in this climate type as well, based on the Köppen-Geiger climate classes Ver. 1 August 1, 2012 15

Weed Risk Assessment for Gymnocoronis spilanthoides

Question ID Answer - Score Notes (and references) Uncertainty (Peel et al., 2007). Using "high" uncertainty. Geo-C9 (Humid cont. cool sum.) y - low N/A Occ: Keszthely, Hungary (CISEH, 2012); Hungary (Torok et al., 2003). Geo-C10 (Subarctic) n - negl N/A No evidence. Geo-C11 (Tundra) n - negl N/A No evidence. Geo-C12 (Icecap) n - negl N/A No evidence. 10-inch precipitation bands Geo-R1 (0-10 inches; 0-25 cm) n - negl N/A No evidence. Geo-R2 (10-20 inches; 25-51 cm) n - negl N/A No evidence. Geo-R3 (20-30 inches; 51-76 cm) y - mod N/A PS: Australia (1 point; GBIF, 2012). Occ: Keszthely, Hungary (CISEH, 2012). Geo-R4 (30-40 inches; 76-102 y - negl N/A PS: Argentina, Australia. cm) Geo-R5 (40-50 inches; 102-127 y - negl N/A PS: Argentina, Australia. cm) Geo-R6 (50-60 inches; 127-152 y - negl N/A PS: Paraguay, Argentina, New Zealand, Japan. cm) Geo-R7 (60-70 inches; 152-178 y - negl N/A PS: Argentina (a few points), New Zealand. cm) Geo-R8 (70-80 inches; 178-203 y - low N/A PS: Bolivia and Brazil (a few points). cm) Geo-R9 (80-90 inches; 203-229 y - low N/A PS: Bolivia. cm) Geo-R10 (90-100 inches; 229-254 y - low N/A PS: Peru. Occ: Kyushu, Japan (Kadono, 2004). cm) Geo-R11 (100+ inches; 254+ cm) y - low N/A PS: Peru. ENTRY POTENTIAL Ent-1 (Plant already here) y - low 1 This species is not known to be naturalized in the United States (Kartesz, 2012; NRCS, 2012). However, an internet search showed it is sold in the United States (Anonymous, 2012; ExtraPlant, 2012). The extent of this species’ distribution in the United States is unknown. Ent-2 (Plant proposed for entry, - N/A or entry is imminent ) Ent-3 (Human value & - N/A In Australia, it was intentionally planted outside in the natural cultivation/trade status) environment for cultivation by the aquarium trade (Parsons and Cuthbertson, 2001). Ent-4 (Entry as a contaminant) Ent-4a (Plant present in Canada, - N/A Mexico, Central America, the Caribbean or China ) Ent-4b (Contaminant of plant - N/A propagative material (except seeds)) Ent-4c (Contaminant of seeds for - N/A planting) Ent-4d (Contaminant of ballast - N/A water) Ent-4e (Contaminant of - N/A aquarium plants or other aquarium products) Ent-4f (Contaminant of - N/A landscape products) Ver. 1 August 1, 2012 16

Weed Risk Assessment for Gymnocoronis spilanthoides

Question ID Answer - Score Notes (and references) Uncertainty Ent-4g (Contaminant of - N/A containers, packing materials, trade goods, equipment or conveyances) Ent-4h (Contaminants of fruit, - N/A vegetables, or other products for consumption or processing) Ent-4i (Contaminant of some - N/A other pathway) Ent-5 (Likely to enter through - N/A natural dispersal)

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