Plant Assessment Form

Acacia melanoxylon

Common Names: blackwood acacia

Evaluated on: 05/20/04 and 5/17/05

List committee review date: 08/07/2005

Re-evaluation date:

Evaluator(s)

John J. Knapp/ Invasive Plant Program Manager
Catalina Island Conservancy
P.O. Box 2739 Avalon, CA 90704
(310) 510-1299
jknapp@catalinaconservancy.org
Elizabeth Brusati/Project Manager
California Invasive Plant Council
1442-A Walnut St. #462, Berkeley, CA 94709
(510) 843-3902
edbrusati@cal-ipc.org

List commitee members

Jake Sigg
Peter Warner
Bob Case
John Knapp
Elizabeth Brusati

General Comments

Due to the lack of information on A. melanoxylon, a small portion of data from related Acacia species were used to complete this ranking, and were specified when used.

Table 2. Criteria, Section, and Overall Scores

Overall Score? Limited
Alert Status? No Alert
Documentation? 3 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes C Reviewed Scientific Publication
Impact?
Four-part score CCUD Total Score
C
1.2 ?Impact on plant community C. Minor Reviewed Scientific Publication
1.3 ?Impact on higher trophic levels U. Unknown
1.4 ?Impact on genetic integrity D. None Reviewed Scientific Publication
2.1 ?Role of anthropogenic and natural disturbance in establishment C. Minor Observational
Invasiveness?
Total Points
9 Total Score C
2.2 ?Local rate of spread with no management B. Increases less rapidly Observational
2.3 ?Recent trend in total area infested within state C. Stable Other Published Material
2.4 ?Innate reproductive potential
(see Worksheet A)
B. Moderate Reviewed Scientific Publication
2.5 ?Potential for human-caused dispersal C. Low Other Published Material
2.6 ? Potential for natural long-distance dispersal C. Rare Observational
2.7 ?Other regions invaded C. Already invaded Reviewed Scientific Publication
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)
D. Very low Observational

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? C Reviewed Scientific Publication
Identify ecosystem processes impacted:

Nutrient levels and distribution are altered within the soil profile, and have long lasting effects. Allelopathic. A. melanoxylon has the ability to fix nitrogen with rates of N-fixation ranging from 0.1 to 32 kg ha-1 year-1. Organic matter and nitrogen levels are increased with a decrease in C:N ratios. Soil nutrient enrichement and nutrient mineralization patterns can persist long after Acacia removal.


Sources of information:

Haubensak, K. 1999. Acacia melanoxylon. Channel Island National Park Service Literature Review. Unpublished.


Question 1.2 Impact on plant community composition,
structure, and interactions?
C Reviewed Scientific Publication
Identify type of impact or alteration:

A. melanoxylon inhibits the germination and growth of native species in the understory. Acacia spp. form dense monospecific stands in South Africa, but not in Hawai'i nor on Santa Catalina Island. Minor impacts in California. Alleolopathic compounds are released in the decomposition of A. melanoxylon leaf litter.


Sources of information:

Souto, X.C., Gonzalez, L. and Reigosa, M.J. 1994. Comparative analysis of allelopathic effects produced by four forestry species durning decompostion prosess in their soils in Galicia (NW Spain). Journal of Chemical Ecology, 20(11):3005-3015.
Haubensak, K. 1999. Acacia melanoxylon. Channel Island National Park Service Literature Review. Unpublished.
Stock, W.D., Wienand, K.T. and Baker, A.C. 1995. Impacts of invading N2-fixing Acacia species on patterns of nutrient cyling in tow Cape ecosystems: evidence from soil incubation studies and 15N natural abundance values. Oecologia. 101(3):375-382.
Knapp, J.J. 2004. Catalina Invasive Plant Ranking Plan for the Catalina Island Conservancy. Unpublished.
Elkhorn Slough National Estuarine Research Reserve. 2000. Weed control by species. Elkhorn Slough National Estuarine Research Reserve. Pp. 1-57.
Peter Warner, California Dept. of Parks and Recreation, pers. obs.
Bob Case, California Native Plant Society, pers. obs.


Question 1.3 Impact on higher trophic levels? U
Identify type of impact or alteration:

unknown


Sources of information:

Question 1.4 Impact on genetic integrity? D Reviewed Scientific Publication

There is only one native Acacia in California, A. greggii (catclaw acacia) and it is an uncommon species of desert washes. Hybridization seems unlikely.


Sources of information:

(1) Hickman, J.C. (ed.). 1993. The Jepson manual of higher plants of California. Pp. 581-582. University of California Press, Berkeley.


Section 2: Invasiveness
Question 2.1 Role of anthropogenic and natural disturbance
in establishment?
B Observational
Describe role of disturbance:

In California, present in sites with human disturbance (1, 3). Germination follows disturbance (2).


Sources of information:

(1) Hickman, J. C. (ed.) 1993. The Jepson Manual, Higher Plants of California. University of California Press. Berkeley, CA
(2) Tunison, T. 1991. Element Stewardship Abstract for Acacia melanoxylon. The Nature Conservancy. Arlington, Virginia. Available: http://tncweeds.ucdavis.edu
(3) Peter Warner, California Dept. of Parks and Recreation, pers. obs.


Question 2.2 Local rate of spread with no management? B Observational
Describe rate of spread:

Controlled in the past on Catalina Island, and many seedlings were detected in 2003 (1). Limited invasiveness on the north coast (2)


Sources of information:

(1) Knapp, J.J. 2004. Catalina Invasive Plant Ranking Plan for the Catalina Island Conservancy. Unpublished
(2) Warner, Peter, California State Parks, Mendocino. pers. comm. E-mail 5/18/05


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

Because Peter Warner reports it as being rarely invasive, it is probably not spreading appreciably in the state.


Sources of information:

(1) Warner, Peter, California State Parks, Mendocino. pers. comm. E-mail 5/18/05


Question 2.4 Innate reproductive potential? B Reviewed Scientific Publication
Describe key reproductive characteristics:

Large long lived soil-seed bank. Reaches reproductive maturity between two to five years. Has coppice resprouts and suckers after disturbance, and germinates readily following fire. Reproduces by seed and root sprouts. In Hawai'i, A. melanoxylon mainly reproduces from root sprouting, but viable seeds are produced from forestry plantings. In California, fruits ripen from July to November. Seeds remain viable for over 50 years in the soil. Seed bank of a related invasive Acacia (A. longifolia), was 50 times larger in the invaded habitat than in the native one. On Catalina Island- numerous seedlings and several large adults were recorded within and just outside Avalon Valley where most recorded populations were planted in private yards and as street tree plantings. Mature naturalized plants were in fruit; however, the viablity of these seeds are unknown, but due to the frequent seedlings detected, seeds are presumed viable.


Sources of information:

Haubensak, K. 1999. Acacia melanoxylon. Channel Island National Park Service Literature Review. Unpublished.
Schierenbeck, K.A., Gallagher, K.G. and Holt, J.N. 1998. The genetics and demography of invasive plant species. Fremontia 26(4):19-23.
Brown, K. and Brooks, K. 2002. Bushland Weeds: a practical guide to their management with case studies from the Swan Coastal Plain and beyond. Environmental Weeds Action Network, Greenwood Australia.
Young, J.A. and C.G. Young. 1992. Seeds of woody plants in North America. Portland, Oregon: Dioscorides Press. Pp. 356-357.


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

Acacia species are commonly planted for landscaping and commercial purposes. No information on how often it escapes (1, 2). In Mendocino County, usually seen along old fencelines or at homestead sites. This species is rarely planted (3).


Sources of information:

(1) Brenzel, K. N. 2001. Sunset Western Garden Book. Sunset Publishing Company, Menlo Park, CA.
(2) Pemberton, R.W. 1985. Naturalized weeds and the prospects for their biological control in California. Fremontia 13(2):3-9.
(3) Warner, Peter, California State Parks, Mendocino. pers. comm. E-mail 5/18/05


Question 2.6 Potential for natural long-distance dispersal? C Observational
Identify dispersal mechanisms:

Birds such as European starlings disperse A. cyclops in South Africa (1). On Catalina Island, present three miles from nearest human habitatation (2).


Sources of information:

Question 2.7 Other regions invaded? C Reviewed Scientific Publication
Identify other regions:

Native to Australia. Invades South Africa (fynbos), Spain, and New Zealand. Already inhabits several different habitats in California, although at low levels (see 3.1).


Sources of information:

Brown, K. and Brooks, K. 2002. Bushland Weeds: a practical guide to their management with case studies from the Swan Coastal Plain and beyond. Environmental Weeds Action Network, Greenwood Australia.
Stock, W.D., Wienand, K.T. and Baker, A.C. 1995. Impacts of invading N2-fixing Acacia species on patterns of nutrient cyling in tow Cape ecosystems: evidence from soil incubation studies and 15N natural abundance values. Oecologia. 101(3):375-382.


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

Present in Mendocino, Sonoma, Marin, Solano, San Mateo, Santa Cruz, Santa Clara, Santa Barbara, and San Diego counties (1). Planted on Catalina Island prior to 1923 and fruiting luxuriantly, but showed no signs of naturalization (2). By 1966, several populations had become naturalized around Avalon (3). Present in chaparral and coastal prairie on Catalina Island (4), and occasionally spreads into scrub, riparian zones, closed cone pine forest, mixed evergreen forest, andn cismontane woodlands in northern California (5).


Sources of information:

(1) USDA, NRCS. 2005. The PLANTS Database, Version 3.5 (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
(2) Millspaugh, C.F. and Nuttall, L.W. 1923. Flora of Santa Catalina Island. P. 154. Field Museum of Natural History, Botany v.5. Chicago.
(3) Thorne, R.F. 1967. A flora of Santa Catalina Island, California. Aliso, 6(3):1-77.
(4) Knapp, J.J. 2004. Catalina Invasive Plant Ranking Plan for the Catalina Island Conservancy. Unpublished.
(5) Warner, Peter, California State Parks, Mendocino. pers. comm. E-mail 5/18/05


Question 3.2 Distribution/Peak frequency? D Observational
Describe distribution:

Very low occurrence in all habitat types.


Sources of information:

(1) Warner, Peter, California State Parks, Mendocino. pers. comm. E-mail 5/18/05


Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less No
Dense infestations produce >1,000 viable seed per square meter No
Populations of this species produce seeds every year. Yes
Seed production sustained over 3 or more months within a population annually No
Seeds remain viable in soil for three or more years Yes
Viable seed produced with both self-pollination and cross-pollination Unknown
Has quickly spreading vegetative structures (rhizomes, roots, etc.) that may root at nodes No
Fragments easily and fragments can become established elsewhere No
Resprouts readily when cut, grazed, or burned Yes
Total points: 4
Total unknowns: 1
Total score: B?

Related traits:

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, reservoirs
Aquatic Systemsrivers, streams, canals
estuaries
Dunescoastal
desert
interior
Scrub and Chaparralcoastal bluff scrub
coastal scrubD, < 5%
Sonoran desert scrub
Mojavean desert scrub (incl. Joshua tree woodland)
Great Basin scrub
chenopod scrub
montane dwarf scrub
Upper Sonoran subshrub scrub
chaparralD, < 5%
Grasslands, Vernal Pools, Meadows, and other Herb Communitiescoastal prairieD, < 5%
valley and foothill grassland
Great Basin grassland
vernal pool
meadow and seep
alkali playa
pebble plain
Bog and Marshbog and fen
marsh and swamp
Riparian and Bottomland habitatriparian forest
riparian woodlandD, < 5%
riparian scrub (incl.desert washes)
Woodlandcismontane woodlandD, < 5%
piñon and juniper woodland
Sonoran thorn woodland
Forestbroadleaved upland forest
North Coast coniferous forest
closed cone coniferous forestD, < 5%
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): D

Infested Jepson Regions

Click here for a map of Jepson regions

  • Cascade Range
  • Central West
  • Great Valley
  • Northwest
  • Sierra Nevada
  • Southwest