Plant Assessment Form

Tamarix parviflora

Synonyms: Tamarix cretica Bge., Tamarix lucronensis Sennen & Elias, Tamarix petteri Presl ex Bge., Tamarix rubella Batt., Tamarix tetranda auct. non Pall., others. Plants are sometimes sold in California as Tamarix africana Poir, which is a different species.

Common Names: smallflower tamarisk

Evaluated on: 1/11/06

List committee review date: 24/01/2006

Re-evaluation date:

Evaluator(s)

Joe DiTomaso
University of California, Davis
Dept Plant Sci, Mail Stop 4, One Shields Ave, Davis CA 95616
530-754-8715
jmditomaso@ucdavis.edu

List commitee members

Joe DiTomaso
Jake Sigg
Peter Warner
Cynthia Roye

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? High
Alert Status? No Alert
Documentation? 3 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes A Other Published Material
Impact?
Four-part score AAAD Total Score
A
1.2 ?Impact on plant community A. Severe Other Published Material
1.3 ?Impact on higher trophic levels A. Severe Other Published Material
1.4 ?Impact on genetic integrity D. None Reviewed Scientific Publication
2.1 ?Role of anthropogenic and natural disturbance in establishment A. Severe Other Published Material
Invasiveness?
Total Points
17 Total Score A
2.2 ?Local rate of spread with no management A. Increases rapidly Other Published Material
2.3 ?Recent trend in total area infested within state A. Increasing rapidly Other Published Material
2.4 ?Innate reproductive potential
(see Worksheet A)
A. High Other Published Material
2.5 ?Potential for human-caused dispersal C. Low Other Published Material
2.6 ? Potential for natural long-distance dispersal A. Frequent Other Published Material
2.7 ?Other regions invaded C. Already invaded Other Published Material
3.1 ?Ecological amplitude/Range
(see Worksheet C)
A. Widespread Other Published Material
Distribution?
Total Score B
3.2 ?Distribution/Peak frequency
(see Worksheet C)
C. Low Other Published Material

Table 3. Documentation

Scores are explained in the "Criteria for Categorizing Invasive Non-Native Plants that Threaten Wildlands".

Section 1: Impact
Question 1.1 Impact on abiotic ecosystem processes? A Other Published Material
Identify ecosystem processes impacted:

Very high water use and increased deposition of salts on soil surface. The longer the community has been invaded by Tamarix the more xeric in nature are the plant species which occupy the understory. Such deposits of salt-encrusted needles can inhibit other species germination. Saltcedar has been blamed for increasing flooding by forming a partial barrier to floodflow, which can cause floodwater to disperse and inundate areas that otherwise would not be flooded. With the invasion of saltcedar there has been an apparent increase in the frequency of fire in riparian ecosystems. Tamarix species can increase flooding in riparian areas by narrowing channel width. In addition, plants are flammable and can introduce fire into wetland and riparian communities that are not adapted to periodic burning. Evapotranspiration rates of saltcedar are among the highest of any phreatophyte evaluated in southwestern North America, including native riparian trees. Saltcedar has been reported to contain 41,000 ppm dissolved solids in the guttation sap. Smallflower tamarisk is very similar both taxonomically and ecologically and, although, it has not been studied to the degree that Tamarix ramosissima, it appears to act very similar in riparian areas.


Sources of information:

Brotherson, J.D. and D. Field. 1987. Tamarix: impacts of a successful weed. Rangelands 9:110-112;
Busch, D.E. and S.D. Smith. 1992. Fire in a riparian shrub community: postburn water relations in the Tamarix-Salix association along thelower Colorado River. Gen. Tech. Rep. Int USDA For. Serv. Intermt. Res. Stn. 289:52-55;
Kerpez, T. A. and N. S. Smith. 1987. Saltcedar control for wildlife habitat improvement in the southwestern United States. USDI. Fish and Wildlife Serv. Resource Publ. 169. p. 1-16.;
DiTomaso, J.M. 1998. Impact, biology, and ecology of saltcedar (Tamarix spp.) in the southwestern United States. Weed Technology 12:236-336 for other references.


Question 1.2 Impact on plant community composition,
structure, and interactions?
A Other Published Material
Identify type of impact or alteration:

Trees typically develop an efficient, deep, extensive root system and have a high evapotranspiration rate in arid climates during the warm season when the roots can access deep soil moisture. Both saltcedar and smallflower tamarisk are facultative phreatophytes that can use both surface and groundwater. The presence of numerous trees along riparian corridors or around desert springs can seriously reduce underground water tables and surface water availability, drying up wetlands, and reducing flows. Roots extract salts from deep soil layers and excrete it from the leaves. Salt is deposited on the soil surface with the leaf litter. The increased salinity of the upper soil profile inhibits the growth, survival, and recruitment of desirable native vegetation. Smallflower tamarisk can form stands considerably more dense than naturally occurring riparian vegetation.


Sources of information:

DiTomaso, J.M. E.A. Healy. 2003. Aquatic and Riparian Weeds of the West. UC DANR Publ. #3421.
DiTomaso, J.M. 1998. Impact, biology, and ecology of saltcedar (Tamarix spp.) in the southwestern United States. Weed Technology 12:236-336 for review and other citations. Many sources of personal observations.


Question 1.3 Impact on higher trophic levels? A Other Published Material
Identify type of impact or alteration:

The majority of birds do not use saltcedar in high proportions compared with native plant communities. Frugivores and insectivores, abundant in native riparian vegetation, almost completely avoid saltcedar. Studies showed that several species had a higher affinity for the cottonwood-willow association, including common flicker, yellow-bellied sapsucker, porcupine and beaver. With the exception of desert woodrat and desert cottontail, no native mammal species are known to feed upon saltcedar. When consumed by wildlife, only young growth is utilized. Although some animals will seek cover or nest in Tamarix thickets, most wildlife does not consume Tamarix foliage, fruits, or seeds. Tamarix species can increase flooding in riparian areas by narrowing channel width. In addition, plants are flammable and can introduce fire into wetland and riparian communities that are not adapted to periodic burning. There is no reason to believe that smallflower tamarisk is used any more than saltcedar by animals. Although certain wildlife species may find saltcedar beneficial to their survival, the encroachment of saltcedar has most certainly altered the native habitat that was apparently of great benefit to wildlife. Although the southwestern willow flycatcher can nest in saltcedar, infestations have a negative impact on most other birds that would normally use the native vegetation


Sources of information:

Numerous papers on the impact of insects, birds, and mammals. Most deal with Tamarix ramosissima. For reviews see:
Lovich, J. Tamarix ramosissima. In, Invasive Plants of Californias Wildlands. Eds., C. Bossard, J. Randall, and M. Hoshovsky. UC Press, Berkeley
DiTomaso, J.M. 1998. Impact, biology, and ecology of saltcedar (Tamarix spp.) in the southwestern United States. Weed Technology 12:236-336 for review and peer-reviewed reference citations.


Question 1.4 Impact on genetic integrity? D Reviewed Scientific Publication

none, but does hybridize with other Tamarix. No native members of the family in north America. Less extensively, hybrids between saltcedar and Chinese tamarisk with smallflower tamarisk (T. parviflora), Canary Island tamarisk (T. canariensis) and French tamarisk (T. gallica) also occur. The abundance of invasive hybrids may explain the confusion associated with the identification of Tamarix species in the western states.


Sources of information:

Gaskin, J.F. and P.B. Shafroth. Hybridization of invasive saltcedars (Tamarix ramosissima, T. chinensis) and athel (T. aphylla) in the southwestern USA, determined from morphology and NA sequence data. Madro_o (in review).


Section 2: Invasiveness
Question 2.1 Role of anthropogenic and natural disturbance
in establishment?
A Other Published Material
Describe role of disturbance:

The development of water management programs that severely impact natural river flows has greatly contributed to spread of saltcedar and smallflower tamarisk. These alterations include reservoir and dam construction, river diversions, flow regulations, and irrigation projects. Historically, the flow of these rivers peaked in the late spring and early summer from snowmelt. These changes in channel geometry and streamflow created conditions unfavorable for the regeneration and survival of native perennial riparian species. As a result, rapid colonization and expansion of saltcedar occurred throughout the western river systems. In addition to altering streamflow, clearing and plowing of floodplains and associated agricultural activity also aided saltcedar colonization during the 1800s. Establishment can occur on disturbed and undisturbed sites, but disturbance can increase the rate of establishment.


Sources of information:

See both Lovich, J. Tamarix ramosissima. In, Invasive Plants of Californias Wildlands. Eds., C. Bossard, J. Randall, and M. Hoshovsky. UC Press, Berkeley
DiTomaso, J.M. E.A. Healy. 2003. Aquatic and Riparian Weeds of the West. UC DANR Publ. #3421.
DiTomaso, J.M. 1998. Impact, biology, and ecology of saltcedar (Tamarix spp.) in the southwestern United States. Weed Technology 12:236-336 for review and peer-reviewed reference citations.


Question 2.2 Local rate of spread with no management? A Other Published Material
Describe rate of spread:

Much of the riparian area in the southwestern US has been occupied by saltcedar and the rate of increase there has slowed down. However, T. parviflora is still vigorously expanding its range. Smallflower tamarisk is not as widely distributed but on Cache Creek it has more than doubled its population in the past 10 years.


Sources of information:

Brotherson, J.D. and D. Field. 1987. Tamarix: impacts of a successful weed. Rangelands 9:110-112;
DiTomaso, J.M. 1998. Impact, biology, and ecology of saltcedar (Tamarix spp.) in the southwestern United States. Weed Technology 12:236-336 for review and peer-reviewed reference citations.
DiTomaso, pers. observation.


Question 2.3 Recent trend in total area infested within state? A Other Published Material
Describe trend:

Recent efforts have begon to target the populations of smallflower tamarisk in much of the Cache Creek watershed in Yolo, Colusa, and Lake counties. This effort is hoped to slow the spread of the species. Currently, however, it has continued to spread rapidly.


Sources of information:

Brotherson, J.D. and D. Field. 1987. Tamarix: impacts of a successful weed. Rangelands 9:110-112;
DiTomaso, J.M. 1998. Impact, biology, and ecology of saltcedar (Tamarix spp.) in the southwestern United States. Weed Technology 12:236-336 for review and peer-reviewed reference citations.
DiTomaso, pers. observation.


Question 2.4 Innate reproductive potential? A Other Published Material
Describe key reproductive characteristics:

Brotherson, J.D. and D. Field. 1987. Tamarix: impacts of a successful weed. Rangelands 9:110-112; Shrader, T.H. Selective management of phreatophytes for improved utilization of natural food-plain resources. Irrigation and Drainage pp. 16-44;
DiTomaso, J.M. 1998. Impact, biology, and ecology of saltcedar (Tamarix spp.) in the southwestern United States. Weed Technology 12:236-336 for review and peer reviewed reference citations.
DiTomaso, J.M. E.A. Healy. 2003. Aquatic and Riparian Weeds of the West. UC DANR Publ. #3421.


Sources of information:

Planted as an ornamental, as a shade tree, and for erosion control. Not nearly as widely planted today as in the past. Can still be purchased via the internet. It was planted as an ornamental shrub or shade tree, or to create wind breaks, or to stabilize eroding stream banks.


Question 2.5 Potential for human-caused dispersal? C Other Published Material
Identify dispersal mechanisms:

Planted as an ornamental, as a shade tree, and for erosion control. Not nearly as widely planted today as in the past. Can still be purchased via the internet. It was planted as an ornamental shrub or shade tree, or to create wind breaks, or to stabilize eroding stream banks.


Sources of information:

DiTomaso, J.M. 1998. Impact, biology, and ecology of saltcedar (Tamarix spp.) in the southwestern United States. Weed Technology 12:236-336 for more details and citations.
DiTomaso, J.M. E.A. Healy. 2003. Aquatic and Riparian Weeds of the West. UC DANR Publ. #3421.


Question 2.6 Potential for natural long-distance dispersal? A Other Published Material
Identify dispersal mechanisms:

The tiny seeds have high viability and long hairs allowing for wind distribution, but may also be carried and deposited along sandbars and riverbanks by water. Stem and root fragments can also float downstream after fragmentation by mechanical damage or flooding and initiate new infestations. Seeds weight about 0.1 mg and can travel long distances in the wind. Flooding can move stem and root fragments very long distances


Sources of information:

Brotherson, J.D. and D. Field. 1987. Tamarix: impacts of a successful weed. Rangelands 9:110-112; Neill, W.M. 1985. Tamarisk. Fremontia 12:22-23;
See both Lovich, J. Tamarix ramosissima. In, Invasive Plants of Californias Wildlands. Eds., C. Bossard, J. Randall, and M. Hoshovsky. UC Press, Berkeley
DiTomaso, J.M. 1998. Impact, biology, and ecology of saltcedar (Tamarix spp.) in the southwestern United States. Weed Technology 12:236-336 for review and other citations.
DiTomaso, J.M. E.A. Healy. 2003. Aquatic and Riparian Weeds of the West. UC DANR Publ. #3421.


Question 2.7 Other regions invaded? C Other Published Material
Identify other regions:

Today, smallflower tamarisk infestations are common in many river systems in the Southern North Coast Ranges, southern Sierra Nevada foothills, eastern Sierra Nevada, Tehachapi Mountains, Central Valley, San Francisco Bay region, eastern South Coast Ranges, South Coast, and deserts, to 800 m. It is also found in Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, scattered in a few central states and many southern and eastern states. Seems to be weedy in areas similar to those in the California and the southwestern US.


Sources of information:

See both Lovich, J. Tamarix ramosissima. In, Invasive Plants of Californias Wildlands. Eds., C. Bossard, J. Randall, and M. Hoshovsky. UC Press, Berkeley
DiTomaso, J.M. 1998. Impact, biology, and ecology of saltcedar (Tamarix spp.) in the southwestern United States. Weed Technology 12:236-336 for review and other citations.
DiTomaso, J.M. E.A. Healy. 2003. Aquatic and Riparian Weeds of the West. UC DANR Publ. #3421.


Section 3: Distribution
Question 3.1 Ecological amplitude/Range? A Other Published Material

Southern North Coast Ranges, southern Sierra Nevada foothills, eastern Sierra Nevada, Tehachapi Mountains, Central Valley, San Francisco Bay region, eastern South Coast Ranges, South Coast, and deserts, to 800 m. Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, scattered in a few central states and many southern and eastern states. First introducted from southern Europe or the eastern Mediterranean region. Although saltcedar is typically found around aquatic or riparian areas, it has also been observed in scrublands, although not in dense stands.


Sources of information:

Neill, W.M. 1985. Tamarisk. Fremontia 12:22-23; See both Lovich, J. Tamarix ramosissima. In, Invasive Plants of Californias Wildlands. Eds., C. Bossard, J. Randall, and M. Hoshovsky. UC Press, Berkeley
DiTomaso, J.M. E.A. Healy. 2003. Aquatic and Riparian Weeds of the West. UC DANR Publ. #3421.
DiTomaso, J.M. 1998. Impact, biology, and ecology of saltcedar (Tamarix spp.) in the southwestern United States. Weed Technology 12:236-336 for review and other citations. Many sources of personal observations.


Question 3.2 Distribution/Peak frequency? C Other Published Material
Describe distribution:

Although not as common as saltcedar, smallflower tamarisk forms dense stands in many riparian areas around the state, particularly in Northern California (Cache Creek), where it infests many riparian communities. It is also in many smaller, isolated water sources that are scattered about the desert (e.g., Red Rock Canyon in the Mojave Desert) and in the coast ranges, such as the Mendocino Headlands State Park, Tomales Bay State Park, and the upper Russian and/or Eel rivers. Smallflower tamarisk is a facultative phreatophyte, which accounts for its primary infestations in riparian and aquatic regions, but occasional occurrence in drier regions.


Sources of information:

Peter Warner, pers. observation
John Randall, pers. observation
DiTomaso, J.M. E.A. Healy. 2003. Aquatic and Riparian Weeds of the West. UC DANR Publ. #3421.
DiTomaso, J.M. 1998. Impact, biology, and ecology of saltcedar (Tamarix spp.) in the southwestern United States. Weed Technology 12:236-336 for review and other citations. Many sources of personal observations.


Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less No
Dense infestations produce >1,000 viable seed per square meter Yes
Populations of this species produce seeds every year. Yes
Seed production sustained over 3 or more months within a population annually Yes
Seeds remain viable in soil for three or more years No
Viable seed produced with both self-pollination and cross-pollination Yes
Has quickly spreading vegetative structures (rhizomes, roots, etc.) that may root at nodes Yes
Fragments easily and fragments can become established elsewhere Yes
Resprouts readily when cut, grazed, or burned Yes
Total points: 9
Total unknowns: 0
Total score: A?

Related traits:

documented to form hybrids with a more invasive congener, tolerates physiologically stressful conditions such as extreme drought and high salinity soils

Worksheet B - Arizona Ecological Types is not included here

Worksheet C - California Ecological Types

(sensu Holland 1986)
Major Ecological Types Minor Ecological Types Code?
Marine Systemsmarine systems
Freshwater and Estuarine lakes, ponds, reservoirsD, < 5%
Aquatic Systemsrivers, streams, canalsC, 5% - 20%
estuaries
Dunescoastal
desert
interior
Scrub and Chaparralcoastal bluff scrub
coastal scrubD, < 5%
Sonoran desert scrub
Mojavean desert scrub (incl. Joshua tree woodland)D, < 5%
Great Basin scrub
chenopod scrub
montane dwarf scrub
Upper Sonoran subshrub scrub
chaparral
Grasslands, Vernal Pools, Meadows, and other Herb Communitiescoastal prairie
valley and foothill grassland
Great Basin grassland
vernal pool
meadow and seepD, < 5%
alkali playa
pebble plain
Bog and Marshbog and fen
marsh and swamp
Riparian and Bottomland habitatriparian forestD, < 5%
riparian woodlandC, 5% - 20%
riparian scrub (incl.desert washes)D, < 5%
Woodlandcismontane woodland
piñon and juniper woodland
Sonoran thorn woodland
Forestbroadleaved upland forest
North Coast coniferous forest
closed cone coniferous forest
lower montane coniferous forest
upper montane coniferous forest
subalpine coniferous forest
Alpine Habitatsalpine boulder and rock field
alpine dwarf scrub
Amplitude (breadth): A
Distribution (highest score): C

Infested Jepson Regions

Click here for a map of Jepson regions

  • Cascade Range
  • Central West
  • Great Valley
  • Northwest
  • Sierra Nevada
  • Southwest
  • Modoc Plateau
  • Sierra Nevada East
  • Desert Province
  • Mojave Desert
  • Sonoran Desert