Pacific Island Ecosystems at Risk (PIER)
RISK ASSESSMENT RESULTS: High risk, score: 24
|
Australian/New Zealand Weed Risk Assessment adapted for Hawai‘i. Information on Risk Assessments Original risk assessment |
| Cortaderia selloana (Common name- pampas grass, silwegras) Synonyms: Arundo selloana, Cortaderia argentea, Gynerium argenteum | Answer | Score | |
| 1.01 | Is the species highly domesticated? | n | 0 |
| 1.02 | Has the species become naturalized where grown? | y | |
| 1.03 | Does the species have weedy races? | n | |
| 2.01 | Species suited to tropical or subtropical climate(s) (0-low; 1-intermediate; 2-high) – If island is primarily wet habitat, then substitute “wet tropical” for “tropical or subtropical” | 2 | |
| 2.02 | Quality of climate match data (0-low; 1-intermediate; 2-high) see appendix 2 | 2 | |
| 2.03 | Broad climate suitability (environmental versatility) | y | 1 |
| 2.04 | Native or naturalized in regions with tropical or subtropical climates | y | 1 |
| 2.05 | Does the species have a history of repeated introductions outside its natural range? y=-2 | y | |
| 3.01 | Naturalized beyond native range y = 1*multiplier (see Append 2), n= question 2.05 | y | 2 |
| 3.02 | Garden/amenity/disturbance weed y = 1*multiplier (see Append 2) | ||
| 3.03 | Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2) | y | 4 |
| 3.04 | Environmental weed y = 2*multiplier (see Append 2) | y | 4 |
| 3.05 | Congeneric weed y = 1*multiplier (see Append 2) | y | 2 |
| 4.01 | Produces spines, thorns or burrs | y | 1 |
| 4.02 | Allelopathic | n | 0 |
| 4.03 | Parasitic | n | 0 |
| 4.04 | Unpalatable to grazing animals | n | -1 |
| 4.05 | Toxic to animals | n | 0 |
| 4.06 | Host for recognized pests and pathogens | n | 0 |
| 4.07 | Causes allergies or is otherwise toxic to humans | n | 0 |
| 4.08 | Creates a fire hazard in natural ecosystems | y | 1 |
| 4.09 | Is a shade tolerant plant at some stage of its life cycle | y | 1 |
| 4.1 | Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island) | y | 1 |
| 4.11 | Climbing or smothering growth habit | n | 0 |
| 4.12 | Forms dense thickets | y | 1 |
| 5.01 | Aquatic | n | 0 |
| 5.02 | Grass | y | 1 |
| 5.03 | Nitrogen fixing woody plant | n | 0 |
| 5.04 | Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers) | n | 0 |
| 6.01 | Evidence of substantial reproductive failure in native habitat | n | 0 |
| 6.02 | Produces viable seed. | y | 1 |
| 6.03 | Hybridizes naturally | ||
| 6.04 | Self-compatible or apomictic | n | -1 |
| 6.05 | Requires specialist pollinators | n | 0 |
| 6.06 | Reproduction by vegetative fragmentation | y | 1 |
| 6.07 | Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1 | 1 | 1 |
| 7.01 | Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas) | y | 1 |
| 7.02 | Propagules dispersed intentionally by people | y | 1 |
| 7.03 | Propagules likely to disperse as a produce contaminant | y | 1 |
| 7.04 | Propagules adapted to wind dispersal | y | 1 |
| 7.05 | Propagules water dispersed | n | -1 |
| 7.06 | Propagules bird dispersed | n | -1 |
| 7.07 | Propagules dispersed by other animals (externally) | Y | 1 |
| 7.08 | Propagules survive passage through the gut | n | -1 |
| 8.01 | Prolific seed production (>1000/m2) | y | 1 |
| 8.02 | Evidence that a persistent propagule bank is formed (>1 yr) | ||
| 8.03 | Well controlled by herbicides | y | -1 |
| 8.04 | Tolerates, or benefits from, mutilation, cultivation, or fire | y | 1 |
| 8.05 | Effective natural enemies present locally (e.g. introduced biocontrol agents) | ||
| Total score: | 24 |
Supporting data:
| Notes | Reference | |
| 1.01 | No evidence | |
| 1.02 | "naturalized in British Isles, s. Europe, s. Africa, Australia, New Zealand, w. United States, & Canary Islands." | http://www.ars-grin.gov/cgi-bin/npgs/html/tax_search.pl |
| 1.03 | "Many varieties of pampas grass are available for use in the landscape. There are dwarf varieties (C. selloana 'Pumila') that are perfect for smaller spaces. Others have pastel colored flowers, while others provide an assortment of leaf variegations ('Silver Stripe', 'Gold Band')." [No evidence that the varieties have characteristics that make them more weedy]. | http://www.floridata.com/ref/c/cort_sel.cfm |
| 2.01 | Native: SOUTHERN AMERICA- Brazil: Brazil, Southern South America: Argentina; Chile; Paraguay; Uruguay." | http://www.ars-grin.gov/cgi-bin/npgs/html/tax_search.pl |
| 2.02 | "naturalized in British Isles, s. Europe, s. Africa, Australia, New Zealand, w. United States, & Canary Islands." | http://www.ars-grin.gov/cgi-bin/npgs/html/tax_search.pl |
| 2.03 |
(1)"An amazing feature about Pampas Grass is that it can live in almost any
habitat. This amazing grass can grow in hard, rocky areas, flooded areas,
dry and damp ground plus its normal habitat. The leaves die during frosts in
northern climates, but grow back in the spring. The habitat it flourishes in
is a damp, warm environment like that of the South American Pampas."
(2)Hardiness: USDA Zone 7a: to -17.7° C (0° F) USDA Zone 7b: to -14.9° C (5° F) USDA Zone 8a: to -12.2° C (10° F) USDA Zone 8b: to -9.4° C (15° F) USDA Zone 9a: to -6.6° C (20° F) USDA Zone 9b: to -3.8° C (25° F) USDA Zone 10a: to -1.1°C (30° F) USDA Zone 10b: to 1.7° C (35° F) |
(1)http://www.blueplanetbiomes.org/pampas_grass.htm (2)http://davesgarden.com/pf/go/1291/ |
| 2.04 | Native: SOUTHERN AMERICA- Brazil: Brazil, Southern South America: Argentina; Chile; Paraguay; Uruguay." | http://www.ars-grin.gov/cgi-bin/npgs/html/tax_search.pl |
| 2.05 | "naturalized in British Isles, s. Europe, s. Africa, Australia, New Zealand, w. United States, & Canary Islands." | http://www.ars-grin.gov/cgi-bin/npgs/html/tax_search.pl |
| 3.01 | "naturalized in British Isles, s. Europe, s. Africa, Australia, New Zealand, w. United States, & Canary Islands." | http://www.ars-grin.gov/cgi-bin/npgs/html/tax_search.pl |
| 3.02 | "It can be found in a variety of habitats from subtropical regions to disturbed areas along roads, and trails. It forms dense stands that can exlude other plants, and its sharp leaves can cut skin and limit recreational use." | http://www.issg.org/database/species/ecology.asp?si=373&fr=1&sts=sss |
| 3.03 | " Although the more aggressive Cortaderia jubata is often called pampas grass, true pampas grass (C. selloana) can also be weedy in California. In other areas of the world, particularly New Zealand and Australia, C. selloana is an important weed problem in forestry operations and conservation areas (Gadgil et al. 1984, Harradine 1991). In forests it competes with seedling trees and can slow their establishment and growth." | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=35&surveynumber=182 |
| 3.04 |
(1)"This plant is considered invasive by the authoritative sources noted
below. This plant may be known by one or more common names in different
places, and some are listed above. Click on an acronym to view each invasive
plant list, or click here for a composite list of Invasive Plants of the
U.S. CalEPPC California Exotic Pest Plant Council. 1999. Exotic Plant Pest List(http://www.cal-ipc.org/1999_cal-ipc_list/, October 19, 1999). California Exotic Pest Plant Council. California. HEAR USDI, Geological Survey. 1999. Information Index for Selected Alien Plants in Hawaii(http://www.hear.org, October 20, 1999). Hawaiian Ecosystems at Risk Project, Biological Resources Division, Haleakala Field Station. Makawao, Hawaii." (2)"In conservation areas pampas grass competes with native vegetation, reduces the aesthetic and recreational value of these areas, and also increases the fire potential." (3)"A problem species in Australia and New Zealand. On New Zealand noxious weed list and banned from sale in that country." (4)"General impacts - C. selloana can form dense stands that exclude other plants. Its sharp leaves cut skin and can limit recreational use of areas, and it can form dense colonies that can become or increase fire hazards (May et al., UNDATED). Once seedlings become established, it is a substantial threat to the ecological quality of preserves, particularly in coastal and grassland sites due to competition with native plants. Its rapid growth and accumulation of above ground and below ground biomass allow it to acquire light, moisture, and nutrients that would be used by other plants. It can be damaging even at low densities because of the amount of cover it can occupy (Starr et al. 2003)." (5)"In South Africa, C. jubata and C. selloana are considered category 1 restricted plants according to the Conservation of Agricultural Resources Act, 1983 (Stellenbosch 2003). Category 1 plants may not occur on any land or inland water surface other than in biological control reserves. Land users are required to control any of these category 1 plants that occur on any land or inland water surface (Stellenbosch 2003)." |
(1)http://plants.usda.gov/java/profile?symbol=COSE4 (2)http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=35&surveynumber=182 (3)http://www.hear.org/pier/species/cortaderia_selloana.htm (4)http://scholar.google.com/scholar?hl=en&q=%22Cortaderia+selloana%22&spell=1 (5)http://www.hear.org/starr/hiplants/reports/html/cortaderia_spp.htm |
| 3.05 | Cortaderia jubata - (1)"In Hawai‘i naturalized in dry to wet zones, from 2000 ft to 7,000 ft. Forms dense monotypic stands in mesic to humid areas with the potential to replace or compete with native species." "A problem species in New Zealand (declared noxious weed). On Hawai‘i noxious weed list." (2)"It is an aggressive colonizer that competes with native vegetation. It can displace native coastal dune, shrub, and estuarine vegetation, and it slows early forest re-growth on logged lands. ... Andean Pampas/Jubata grass is a threat to the integrity of coastal dune, shrub and estuarine ecosystems." (3)"Jubatagrass is one of the most invasive nonnative species along sensitive natural coastal sites of California." (4)It is on the 'State Noxious weed list' of 46 states in the U.S. | (1)http://www.hear.org/pier/species/cortaderia_jubata.htm (2)http://www.nps.gov/archive/redw/pampas.htm (3)Drewitz, Jennifer J.; DiTomaso, Joseph M. Seed biology of jubatagrass (Cortaderia jubata) Weed Science 52 (4) : 525-530 July 2004 (4)http://plants.usda.gov/java/profile?symbol=COJU2 |
| 4.01 | (1)"Danger: Plant has spines or sharp edges; use extreme caution when handling." (2)" It forms dense stands that can exlude other plants, and its sharp leaves can cut skin and limit recreational use." | (1)http://davesgarden.com/pf/go/1291/ (2)http://www.issg.org/database/species/ecology.asp?si=373&fr=1&sts=sss |
| 4.02 | Not allelopathic | http://plants.nrcs.usda.gov/cgi_bin/topics.cgi?earl=plant_attribute.cgi&symbol=COSE4 |
| 4.03 | No evidence | |
| 4.04 | Low browse and graze palatibility. | http://plants.nrcs.usda.gov/cgi_bin/topics.cgi?earl=plant_attribute.cgi&symbol=COSE4 |
| 4.05 | Toxicity - none. | http://plants.nrcs.usda.gov/cgi_bin/topics.cgi?earl=plant_attribute.cgi&symbol=COSE4 |
| 4.06 | This speceis lists 23 fungi species to be associated with C.selloana. [No evidence of economic pests being associated with C. selloana]. | http://nt.ars-grin.gov/fungaldatabases/index.cfm |
| 4.07 | Toxicity - none. | http://plants.nrcs.usda.gov/cgi_bin/topics.cgi?earl=plant_attribute.cgi&symbol=COSE4 |