Plant Assessment Form

Geranium dissectum

Synonyms: Geranium laxum Hanks

Common Names: cutleaf geranium

Evaluated on: 6/10/05

List committee review date: 08/07/2005

Re-evaluation date:

Evaluator(s)

Peter Warner
California Dept. of Parks & Recreation
P. O. Box 603, Little River, CA 95456
(707) 937-9172; (707) 937-2278
pwarn@parks.ca.gov; corylus@earthlink.net

List commitee members

Jake Sigg
Bob Case
Peter Warner
John Knapp
Elizabeth Brusati

General Comments

This PAF based primarily on the personal observations of the evaluator.

Table 2. Criteria, Section, and Overall Scores

Overall Score? Limited
Alert Status? No Alert
Documentation? 1.5 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes U
Impact?
Four-part score UDUU Total Score
Could not calculate
1.2 ?Impact on plant community D. Negligible Observational
1.3 ?Impact on higher trophic levels U. Unknown
1.4 ?Impact on genetic integrity U. Unknown
2.1 ?Role of anthropogenic and natural disturbance in establishment B. Moderate Observational
Invasiveness?
Total Points
12 Total Score B
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 Observational
2.5 ?Potential for human-caused dispersal A. High Observational
2.6 ? Potential for natural long-distance dispersal C. Rare Observational
2.7 ?Other regions invaded C. Already invaded Other Published Material
3.1 ?Ecological amplitude/Range
(see Worksheet C)
A. Widespread Observational
Distribution?
Total Score A
3.2 ?Distribution/Peak frequency
(see Worksheet C)
A. High 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? U
Identify ecosystem processes impacted:

None known.


Sources of information:

Question 1.2 Impact on plant community composition,
structure, and interactions?
D Observational
Identify type of impact or alteration:

Once established, G. dissectum appears to displace herbaceous native plant species; dense infestations could preclude, to an unknown degree, development of perennials and even woody species. However, this plant is primarily dominant and weedy in disturbed areas, not so much so in relatively intact plant communities. Impact assessed based on observed density and dominance of G. dissectum in some plant communities.


Sources of information:

Warner, PJ. 1996-2005. Personal observations in San Mateo, San Francisco, Marin, Sonoma, and Mendocino Counties, CA. 707-937-9172/pwarn@parks.ca.gov


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

Could sharp-tipped fruits be injurious to animals?


Sources of information:

Question 1.4 Impact on genetic integrity? U

This species could hybridize with its native congeners, but this potential element of risk is unknown.


Sources of information:

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

G. dissectum appears to be more invasive in disturbed areas, such as long-grazed pastures or woodlands, trailsides, and sand dunes. However, some areas of relatively stable hind-dunes along the northern Calif. coast, as well as formerly grazed interior oak woodlands and grasslands, are infested with G. dissectum, suggesting that frequent or sustained disturbance are not necessary for its persistence in some areas.


Sources of information:

Warner, PJ. 1996-2005. Personal observations in San Mateo, San Francisco, Marin, Sonoma, and Mendocino Counties, CA. 707-937-9172/pwarn@parks.ca.gov


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

Without new disturbance, G. dissectum does not appear to spread rapidly. However, it will establish in new areas on a limited basis, but generally does not form dominant colonies where other species are already well established.


Sources of information:

Warner, PJ. 1996-2005. Personal observations in San Mateo, San Francisco, Marin, Sonoma, and Mendocino Counties, CA. 707-937-9172/pwarn@parks.ca.gov


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

This plant has been well established in California for many years; area infested would seem likely to be stable.


Sources of information:

Warner, PJ. 1996-2005. Personal observations in San Mateo, San Francisco, Marin, Sonoma, and Mendocino Counties, CA. 707-937-9172/pwarn@parks.ca.gov


Question 2.4 Innate reproductive potential? B Observational
Describe key reproductive characteristics:

dense populations capable of producing copious amounts of seed over a prolonged period.


Sources of information:

Warner, PJ. 1996-2005. Personal observations in San Mateo, San Francisco, Marin, Sonoma, and Mendocino Counties, CA. 707-937-9172/pwarn@parks.ca.gov


Question 2.5 Potential for human-caused dispersal? A Observational
Identify dispersal mechanisms:

long--awned fruits that stick in clothing, machinery; also spread in contaminated hay or grain


Sources of information:

Warner, PJ. 1996-2005. Personal observations in San Mateo, San Francisco, Marin, Sonoma, and Mendocino Counties, CA. 707-937-9172/pwarn@parks.ca.gov


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

Fruits can become attached to animal fur.


Sources of information:

Warner, PJ. 1996-2005. Personal observations in San Mateo, San Francisco, Marin, Sonoma, and Mendocino Counties, CA. 707-937-9172/pwarn@parks.ca.gov


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

Native to Europe; widespread in North America; not as common in Plains and intermountain West (1). From CalFlora Database, G. dissectum appears to have invaded most parts (and ecosystems) in CA (2).


Sources of information:

1. USDA, NRCS. 2004. The PLANTS Database, Version 3.5 (http://plants.usda.gov) .National Plant Data Center , Baton Rouge, LA 70874-4490 USA.
2. CalFlora: Information on California plants for education, research
and conservation. [web application]. 2005.
Berkeley, California: The CalFlora Database [a non-profit organization].
Available: http://www.calflora.org/.
[Accessed: 65 July 2005]


Section 3: Distribution
Question 3.1 Ecological amplitude/Range? A Observational

I've observed G. dissectum in virtually every coastal plant community, as well as numerous North Coast Range lower elevation plant communities; the plant is also common in interior woodlands and grasslands (1). Most counties in Calif. report G. dissectum as occurring (2).


Sources of information:

1. Warner, PJ. 1996-2005. Personal observations in San Mateo, San Francisco, Marin, Sonoma, and Mendocino Counties, CA. 707-937-9172/pwarn@parks.ca.gov
2. CalFlora: Information on California plants for education, research
and conservation. [web application]. 2005.
Berkeley, California: The CalFlora Database [a non-profit organization].
Available: http://www.calflora.org/.
[Accessed: 65 July 2005]


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

Common in many ecological types, based on my plant lists of various habitat types in northern CA; also observed in several southern CA ecosystems.


Sources of information:

Warner, PJ. 1996-2005. Personal observations in San Mateo, Marin, Sonoma, and Mendocino Counties, CA. 707-937-9172/pwarn@parks.ca.gov


Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less Yes
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 No
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 No
Total points: 4
Total unknowns: 0
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
DunescoastalB, 20% - 50%
desert
interior
Scrub and Chaparralcoastal bluff scrubB, 20% - 50%
coastal scrubC, 5% - 20%
Sonoran desert scrub
Mojavean desert scrub (incl. Joshua tree woodland)
Great Basin scrub
chenopod scrub
montane dwarf scrub
Upper Sonoran subshrub scrub
chaparral
Grasslands, Vernal Pools, Meadows, and other Herb Communitiescoastal prairieA, > 50%
valley and foothill grasslandA, > 50%
Great Basin grassland
vernal pool
meadow and seepC, 5% - 20%
alkali playa
pebble plain
Bog and Marshbog and fen
marsh and swamp
Riparian and Bottomland habitatriparian forest
riparian woodlandC, 5% - 20%
riparian scrub (incl.desert washes)
Woodlandcismontane woodlandB, 20% - 50%
piñon and juniper woodland
Sonoran thorn woodland
Forestbroadleaved upland forestC, 5% - 20%
North Coast coniferous forestD, < 5%
closed cone coniferous forestC, 5% - 20%
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): A

Infested Jepson Regions

Click here for a map of Jepson regions

  • CA Floristic Province
  • Cascade Range
  • Central West
  • Great Valley
  • Modoc Plateau
  • Northwest
  • Sierra Nevada
  • Southwest