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 |
| Rubus discolor (Himalayan blackberry, Himalayaberry) Synonyms: Rubus armeniacus, Rubus fruticosus L., Rubus grabowskii Weihe ex Gunther et al., Rubus macrostemon (Focke) Sampaio, Rubus praecox Bertol., Rubus procerus auct. non P.J. Muell. ex Genev, Rubus thyrsanthus (Focke) Foerster. family - Rosaceae. | Answer | Score | |
| 1.01 | Is the species highly domesticated? (If answer is 'no' then go to question 2.01) | n | 0 |
| 1.02 | Has the species become naturalized where grown? | ||
| 1.03 | Does the species have weedy races? | ||
| 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” | 1 | |
| 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 | n | 0 |
| 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 | n | 0 |
| 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 | y | 1 |
| 6.05 | Requires specialist pollinators | ||
| 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 | 2 | 0 |
| 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 | n | -1 |
| 7.04 | Propagules adapted to wind dispersal | n | -1 |
| 7.05 | Propagules water dispersed | y | 1 |
| 7.06 | Propagules bird dispersed | y | 1 |
| 7.07 | Propagules dispersed by other animals (externally) | n | -1 |
| 7.08 | Propagules survive passage through the gut | y | 1 |
| 8.01 | Prolific seed production (>1000/m2) | y | 1 |
| 8.02 | Evidence that a persistent propagule bank is formed (>1 yr) | y | 1 |
| 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 | ||
| 1.03 | ||
| 2.01 |
(1) "Himalayan blackberry is native to western Europe (Hickman 1993) . There
is no botanical evidence to show that it is native to the Himalayan region.
It may have found its way there as a cultivar." (2) Native range: Rubus
discolor is native to western Europe (3) Native Range Austria Bulgaria France Hungary Morocco Portugal Spain Alien Range:- Australia Canada New Zealand South Africa United States (USA) |
(1) http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 (2) http://www.hear.org/starr/hiplants/reports/html/rubus_discolor.htm (3) http://www.invasivespecies.net/database/species/distribution.asp?si=994&fr=1&sts= |
| 2.02 |
(1) "Himalayan blackberry is native to western Europe (Hickman 1993) . There
is no botanical evidence to show that it is native to the Himalayan region.
It may have found its way there as a cultivar." (2) Native range: Rubus
discolor is native to western Europe (3) Native Range Austria Bulgaria France Hungary Morocco Portugal Spain Alien Range:- Australia Canada New Zealand South Africa United States (USA) |
(1) http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 (2) http://www.hear.org/starr/hiplants/reports/html/rubus_discolor.htm (3) http://www.invasivespecies.net/database/species/distribution.asp?si=994&fr=1&sts= |
| 2.03 | (1) Hardy to USDA Zone 6 (2) Elevation: < 1600 m. | (1) http://oregonstate.edu/dept/ldplants/rudis.htm (2) http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?6677,6899,6900 |
| 2.04 |
(1) "The Himalayan blackberry is a native of the Old World [3,31]. However, it has become widely naturalized in the Northeast from Delaware to Virginia, and in the Pacific Northwest [3]. The Himalayan blackberry occurs from northern California through southern British Columbia eastward to Idaho. It is particularly widespread west of the Cascades [14] and is now abundant along the Snake River in southeastern Washington [13]. It is also locally established in parts of Utah and perhaps Arizona [19,31]." (2) "R. discolor is widely cultivated; it has escaped and become naturalized throughout the western US (Alaska Natural Heritage Program, 2005) ." |
(1) http://www.fs.fed.us/database/feis/plants/shrub/rubdis/distribution_and_occurrence.html (2) http://www.issg.org/database/species/ecology.asp?si=994&fr=1&sts=sss |
| 2.05 |
(1) "The Himalayan blackberry is a native of the Old World [3,31]. However, it has become widely naturalized in the Northeast from Delaware to Virginia, and in the Pacific Northwest [3]. The Himalayan blackberry occurs from northern California through southern British Columbia eastward to Idaho. It is particularly widespread west of the Cascades [14] and is now abundant along the Snake River in southeastern Washington [13]. It is also locally established in parts of Utah and perhaps Arizona [19,31]." (2) "R. discolor is widely cultivated; it has escaped and become naturalized throughout the western US (Alaska Natural Heritage Program, 2005) ." |
(1) http://www.fs.fed.us/database/feis/plants/shrub/rubdis/distribution_and_occurrence.html (2) http://www.issg.org/database/species/ecology.asp?si=994&fr=1&sts=sss |
| 3.01 |
(1) "The Himalayan blackberry is a native of the Old World [3,31]. However, it has become widely naturalized in the Northeast from Delaware to Virginia, and in the Pacific Northwest [3]. The Himalayan blackberry occurs from northern California through southern British Columbia eastward to Idaho. It is particularly widespread west of the Cascades [14] and is now abundant along the Snake River in southeastern Washington [13]. It is also locally established in parts of Utah and perhaps Arizona [19,31]." (2) "R. discolor is widely cultivated; it has escaped and become naturalized throughout the western US (Alaska Natural Heritage Program, 2005) ." |
(1) http://www.fs.fed.us/database/feis/plants/shrub/rubdis/distribution_and_occurrence.html (2) http://www.issg.org/database/species/ecology.asp?si=994&fr=1&sts=sss |
| 3.02 | (1) "It forms impenetrable thickets in wastelands, pastures, and forest plantations. It grows along roadsides, creek gullies, river flats, fence lines (Parsons and Amor 1968) , and right-of-way corridors. It is common in riparian areas, where it establishes and persists despite periodic inundation by fresh or brackish water. " "The impenetrable nature of blackberry thickets reduces access for maintenance of fence lines and for forestry practices, as well as recreational pursuits." [Not scored because 3.04 is scored positive as a weed]. | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 3.03 | (1) "It forms impenetrable thickets in wastelands, pastures, and forest plantations. It grows along roadsides, creek gullies, river flats, fence lines (Parsons and Amor 1968) , and right-of-way corridors. It is common in riparian areas, where it establishes and persists despite periodic inundation by fresh or brackish water. " (2) "Invasiveness: Rubus discolor is a brambling vine that bears sharp prickles and forms impenetrable thickets. Rubus discolor spreads rapidly from plantings and is considered a pest plant in the United States, particularly on the west coast and some north eastern states (PLANTS 2003) . In these areas, R. discolor spreads in wastelands, pastures, forest plantations, along roads, creek gullies, river flats, and fence lines (Parsons and Amor 1968, Amor 1973) . In Hawai'i, R. discolor is spreading on Maui and O'ahu." | (1) http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 (2) http://www.hear.org/starr/hiplants/reports/html/rubus_discolor.htm |
| 3.04 |
(1) "General impacts R. discolor colonizes areas initially disturbed and then neglected by humans. It then forms large impenetrable thickets of prickly canes with densities reaching 525 canes per square meter. A large quantity of litter develops in mature thickets. The thickets create dense shade, reducing native species diversity and likely limiting mammal movement in gaining access to water. In addition, the tangled mass of thorny stems blocks access of humans, livestock, equipment, and vehicles to pastures and waterways. These dense thickets and litter buildup represent potential fire hazards (Alaska Natural Heritage Program, 2005; and Hoshovsky, 1989) . R. discolor is a perennial weed which is difficult to control due to its ability to regenerate from sections of root stock. In forest areas, timber-logging operations create large open areas that are often invaded by R. discolor. When grazed, the thorny stems can injure nasal passages of livestock. Another undesirable aspect of R. discolor is that they are a good source of food and shelter for rats (DiTomaso, 2006; and Hoshovsky, 1989) ." (2) "Noxious weed acts: Rubus discolor is a category B noxious weed in the state of Oregon (INVADERS 2003) ." |
(1) http://www.issg.org/database/species/ecology.asp?si=994&fr=1&sts=sss (2) http://www.hear.org/starr/hiplants/reports/html/rubus_discolor.htm |
| 3.05 | (1) Rubus argutus (2) Rubus ellipticus and (3) Rubus moluccanus | (1) http://www.issg.org/database/species/ecology.asp?si=476&fr=1&sts=sss (2) http://www.issg.org/database/species/ecology.asp?si=79&fr=1&sts=sss (3) http://www.issg.org/database/species/ecology.asp?si=994&fr=1&sts=sss |
| 4.01 | "Canes have hooked prickles." | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 4.02 | No evidence | |
| 4.03 | No evidence | |
| 4.04 |
"Grazing: Sheep, cattle, and horses can be effective in reducing the spread
of Himalayan blackberry (Amor 1974) . In New Zealand infestations have been
controlled by the grazing of large numbers of goats. This method has been
effective in preventing canes from covering large areas (Featherstone 1957) .
Crouchley (1980) mentions that blackberry is readily eaten by goats
throughout the year, even when there is an abundant supply of other plants.
In many areas of California the use of angora and Spanish goats is showing
promise in controlling Himalayan blackberry (Daar 1983) ." "Because plants are prickly, livestock, particularly sheep and cattle, avoid grazing near them, effectively decreasing the usable pasture area. Young sheep and goats that get tangled up in the canes have been known to die of thirst and hunger." [No -based on the first reference]. |
http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 4.05 | Probably not - "Grazing: Sheep, cattle, and horses can be effective in reducing the spread of Himalayan blackberry (Amor 1974) . In New Zealand infestations have been controlled by the grazing of large numbers of goats. This method has been effective in preventing canes from covering large areas (Featherstone 1957) . Crouchley (1980) mentions that blackberry is readily eaten by goats throughout the year, even when there is an abundant supply of other plants. In many areas of California the use of angora and Spanish goats is showing promise in controlling Himalayan blackberry (Daar 1983) ." | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 4.06 | (1) This site lists over 30 fungi species to be associated with Rubus discolor. According to - http://www.aphis.usda.gov/index.shtml - at the time of this writing, there were 27 fungi species listed (now more) , with no evidence that any of those 27 were economic pests. Probably not - (2) Pests and diseases: Not known. |
https://nt.ars-grin.gov/fungaldatabases/fungushost/new_frameFungusHostReport.cfm
|
| 4.07 | No evidence | |
| 4.08 | "Dense thickets around farm buildings and fence lines are a considerable fire hazard." "Individual canes may live only two to three years yet reach a density of 525 canes per square meter. A large quantity of litter and standing dead canes develops in old thickets." | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 4.09 | "In Australia Himalayan blackberry seedlings receiving less than 44 percent of full sunlight did not survive (Amor 1974) . The slow growth of seedlings and their intolerance of shading suggest that few seedlings would be expected to survive in dense pastures or forest plantations." "Reestablishment of Himalayan blackberry may be prevented by planting fast-growing shrubs or trees, since the species is usually intolerant of shade." | |
| 4.1 | "Blackberries grow well on a variety of barren, infertile soil types (Brinkman 1974) . These shrubs tolerate a wide range of soil pH and texture, but do require adequate soil moisture." | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 4.11 | "Sprawling, essentially evergreen, glandless, robust shrub. The shrubs appear as “great mounds or banks” (Bailey 1945) . Stems: some canes to 10 ft (3 m) tall, others decumbent, trailing, or scandent to 20-40 ft (6-12 m) long …" | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 4.12 | "Himalayan blackberry (Rubus discolor) grows as a dense thicket of long, bending branches (canes) , appearing as tall, ten-foot mounds or banks, particularly along watercourses." "It forms impenetrable thickets in wastelands, pastures, and forest plantations." | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 5.01 | "Sprawling, essentially evergreen, glandless, robust shrub. The shrubs appear as “great mounds or banks” (Bailey 1945) . Stems: some canes to 10 ft (3 m) tall, others decumbent, trailing, or scandent to 20-40 ft (6-12 m) long …" | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 5.02 | ||
| 5.03 | ||
| 5.04 | ||
| 6.01 | No evidence | |
| 6.02 | "Seeds germinate mainly in spring." | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 6.03 | Don’t know - hybridization is well documented in the Rubus genus but no evidence of natural hybrids of R. discolor. | |
| 6.04 |
"The following types of reproduction have been documented in blackberries: (1) sexual reproduction, (2) nonreduction at meiosis on the female, male, or both sides, (3) apomixis (seeds contain embryos of maternal, rather than sexual origin) with segregation, (4) apomixis without segregation, and (5) haploid parthenogenesis [6]. These modes of asexual reproduction contribute significantly to the aggressive, vigorous spread of blackberries." |
http://www.fs.fed.us/database/feis/plants/ shrub/rubdis/botanical_and_ecological_characteristics.html |
| 6.05 | Pollination: Not known. | http://www.hear.org/starr/hiplants/reports/html/rubus_discolor.htm |
| 6.06 | "It seeds heavily, and seeds are readily dispersed by mammals and birds. Seeds can be spread considerable distances by streams and rivers (Parsons 1992) . It also spreads vegetatively by rooting of cane tips." | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 6.07 |
(1) "Stems of most blackberries are biennial. Sterile first-year stems, or primocanes, develop from buds at or below the ground surface and bear only leaves. During the second year, lateral branches, known as floricanes, develop in the axils of the primocanes, and produce both leaves and flowers." (2) "Lifecycle stages R. discolor is capable of clonal growth as well as sexual reproduction and has perennial roots that may simultaneously bear several biennial canes. During the first year, a cane remains entirely vegetative and growth is limited to elongation of the cane. In the spring of the second year, lateral shoots develop from buds in the leaf axils and the first-year leaves senesce. Growth during the second year is limited to lateral shoot elongation. Inflorescences are borne in the axils of leaves and at the terminal apex of each lateral shoot. R. discolor can form roots at cane apices. Daughter plants develop where these canes root. Canes produce berries in their second year and then die. Re-entry of canes into the center of the thicket result in an impenetrable mass of prickly canes. Individual canes may only live 2-3 years, yet reach a density of 525 canes per square meter. R. discolor can also readily propagate from root pieces and cane cuttings." |
(1) http://www.fs.fed.us/database/feis/plants/shrub/ rubdis/botanical_and_ecological_characteristics.html (2) http://www.issg.org/database/species/ecology.asp?si=994&fr=1&sts=sss |
| 7.01 | Probably yes - " It grows along roadsides, creek gullies, river flats, fence lines (Parsons and Amor 1968) , and right-of-way corridors." | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 7.02 | "Humans transport the plant long distances for use as an ornamental or as an edible crop." | http://www.hear.org/starr/hiplants/reports/html/rubus_discolor.htm |
| 7.03 | No evidence that the species is grows or is cultivated in or around seed crops. | |
| 7.04 | No evidence | |
| 7.05 | "It seeds heavily, and seeds are readily dispersed by mammals and birds. Seeds can be spread considerable distances by streams and rivers (Parsons 1992) . It also spreads vegetatively by rooting of cane tips." | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 7.06 | "It seeds heavily, and seeds are readily dispersed by mammals and birds. Seeds can be spread considerable distances by streams and rivers (Parsons 1992) . It also spreads vegetatively by rooting of cane tips." "Seeds of blackberries are readily dispersed by gravity and by many species of birds and mammals. The large, succulent fruits are highly favored and, after they mature, rarely remain on the plant for long (Brinkman 1974) . A hard seed coat protects the embryo even when seeds are ingested. Passing through animal digestive tracts appears to scarify seeds and may enhance germination." | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 7.07 | No evidence that the propagules have any means of attachment. | |
| 7.08 | "It seeds heavily, and seeds are readily dispersed by mammals and birds. Seeds can be spread considerable distances by streams and rivers (Parsons 1992) . It also spreads vegetatively by rooting of cane tips." "Seeds of blackberries are readily dispersed by gravity and by many species of birds and mammals. The large, succulent fruits are highly favored and, after they mature, rarely remain on the plant for long (Brinkman 1974) . A hard seed coat protects the embryo even when seeds are ingested. Passing through animal digestive tracts appears to scarify seeds and may enhance germination." | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 8.01 | "Himalayan blackberry thickets can produce 7,000 to 13,000 seeds per square meter (Amor 1974) ." | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
| 8.02 |
(1) "Prompt invasion of cut-over lands by Himalayan blackberry suggests that
dispersed seeds can remain viable in the soil for several years (Brinkman
1974) ." (2) "Seedbanking: Seeds of most blackberries can remain viable when
stored in the soil for a period of at least several years [2]. However, the specific length of viability has not been documented for the Himalayan blackberry.z" |
(1) http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182
(2) http://www.fs.fed.us/database/feis/plants/shrub/ rubdis/botanical_and_ecological_characteristics.html |
| 8.03 |
(1) "Picloram suppresses cane regrowth of Himalayan blackberry but stimulates
the development of adventitious shoots. Picloram is currently not registered
for use in California wildlands. Foliage spraying is more effective in
summer than in winter. Many other herbicides have been used in efforts to
control Himalayan blackberry with varying degrees of effectiveness. Fosamine
can be effective (Shaw and Bruzzese 1979) , and blackberry control has also
been accomplished with amitrole-thiocyanate (Amor 1972) , and triclopyr ester
(as Garlon®) (McCavish 1980) . Not all of these are currently registered for
use in California." (2) "Chemical control: Good to excellent control of the
Himalayan blackberry can be obtained through the use of glyphosate, picloram + 2,4-D, triclopyr ester, or triclopyr amine [4]." |
(1) http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182
(2) http://www.fs.fed.us/database/feis/plants/ shrub/rubdis/management_considerations.html |
| 8.04 |
"The Himalayan blackberry is well adapted to invade recently burned sites. Most blackberries sprout vigorously after fire [9]. Various regenerative structures located at or below the ground surface enable this shrub to sprout, even when aboveground foliage is totally consumed by fire. Sprouting through rooting stem nodes [32] is also likely if even portions of the aboveground stem remain undamaged." |
http://www.fs.fed.us/database/feis/plants/shrub/ rubdis/botanical_and_ecological_characteristics.html |
| 8.05 | "Insects and fungi: The USDA will not support introduction of herbivorous insects to control Himalayan blackberry because of the risk posed to commercially important Rubus species. " | http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=71&surveynumber=182 |
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This page was created on 26 December 2006 by JS, and was last updated on 30 June 2017 by PT.