An Assessment of Exotic Plant Species of Rocky Mountain National Park

Appendix II - Ranking System for Rocky Mountain National Park

Potential Distribution in Rocky Mountain National Park
1. Ability to complete reproductive cycle in various communities of RMNP
a. not expected to complete reproductive cycle in any communities	0
b. capable of completing reproductive cycle in a small range of communities	1
c. capable of completing reproductive cycle in a moderate range of communities	3
d. capable of completing reproductive cycle in a wide range of communities	5
2. Germination requirements
a. requires open soil and disturbance to germinate	0
b. can germinate in vegetated areas but in a narrow range or special conditions	3
c. can germinate in existing vegetation under a wide range of conditions	5
3. Dispersal ability
a. little potential for long distance dispersal	0
b. medium potential for long distance dispersal	3
c. great potential for long distance dispersal	5
Total possible=15
Potential Impact on Communities of Concern
1. Ability to complete reproductive cycle in area of concern
a. low potential to complete reproductive cycle in area of concern based on literature	0
b. medium potential to complete reproductive cycle in area of concern based on literature	3
c. high potential to complete life cycle in area of concern based on literature	5
2. Mode of reproduction
a. reproduces almost entirely by vegetative means	1
b. reproduces only by seeds	3
c. reproduces vegetatively and by seeds	5
3. Vegetative reproduction
a. no vegetative reproduction	0
b. vegetative reproduction rate maintains population	1
c. vegetative reproduction rate results in a moderate rate of increase in population size	3
d. vegetative reproduction results in a rapid rate of increase in population size	5
4. Frequency of sexual reproduction for mature plant
a. almost never reproduces sexually in area	0
b. once every five or more years	1
c. every other year	3
d. one or more times a year	5
5. Number of seeds per plant
a. few (0-10)	0
b. moderate (11 - 1,000)	3
c. many seeded (> 1000)	5
6. Competitive ability
a. poor competitor for limiting factors	0
b. moderately competitive for limiting factors	3
c. highly competitive for limiting factors	5
7. Known level of impact in natural areas
a. not known to cause impacts in any other natural area	0
b. known to cause impacts in natural areas, but in other habitats and different climatic zones	1
c. known to cause low impact in natural areas in similar habitats and climate zones	3
d. known to cause moderate impacts in natural areas in similar habitats and climate zones	5
e. known to cause high impacts in natural areas in similar habitats and climate zones	10
Total possible=40
* Final Assessment is required for all species which receive a score equal to, or greater than 24 for this section.

Section II Final Assessment
Feasibility of Control

(Information for this section obtained from literature review)

Ease of Control
A. Ease of Control
1. Seed banks
a. seeds remain viable in the soil for at least 3 years	0
b. seeds remain viable in the soil for 2-3 years	5
c. seeds remain viable in the soil for 1 year or less	15
2. Vegetative regeneration
a. any plant part is a viable propagule	0
b. sprouts from roots or stumps	5
c. no resprouting following removal of aboveground growth	10
3. Level of effort required
a. repeated chemical or mechanical control measures required	1
b. one or two chemical or mechanical control effortrs required	5
c. can be controlled with one chemical treatment	10
d. effective control can be achieved with mechanical treatment	15
4. Side effects of chemical/mechanical control measures
a. control efforts will cause impacts to communities	0
b. control measures will cause moderate impacts to communities	5
c. control measures will have little or no impact on communities	15
5. Effectiveness of community management
the following options are not effective	0
a. cultural techniques (burning, flooding, or mechanical removal) can be used to control species	5
b. routine management of community or restoration or preservation practices (e.g. prescribed burning or controlled disturbance) effectively controls species	10
6. Biological control
a. biological control not feasible (not practical, possible, or probable)	0
b. potential may exist for biological control	5
c. biological control feasible	10
Sub-total=75
(Information for this section obtained from field surveys)
B. Abundace Within Park
1. Number of known populations (stands) based on available field data
a. several; widespread and dense	1
b. intermediate number; patchy	3
c. few; scattered feasible	5
2. Aerial extent of populations
a. > 50 ha	1
b. 11-50 ha	2
c. 5-10 ha	3
d. < 5 ha	4
C. Abundance and Proximity of Propagules to Park
1. many sources of porpagules near park	0
2. few sources of propagules near park, but these are readily dispersed	5
3. few sources of propagules near park, but these are not readily dispersed	10
4. no sources of propagules are in close proximity	15
Total possible=100

Significance of Impact

(Information for this section obtained from field surveys)

Current level of Impact
A. Distribution relative to disturbance regime
1. found only on sites disturbed within the last 3 years of sites regularly disturbed	-10
2. found in sites disturbed within the last 10 years	1
3. found in mid-succesional sites disturbed 11-50 years before present (BP)	2
4. found in late succesional sites disturbed 51-100 years BP	5
5. found in high quality natural areas with no known major disturbace for 100 years	10
B. Abundance
1. Number of populations (stands)
a. few; scattered (<5)	1
b. intermediate number; patchy (6-10)	3
c. several; widespread and dense (>10)	5
2. Aerial extent of populations
a. < 5 ha	1
b. 5-10 ha	2
c. 11-50 ha	3
d. > 50 ha	5
3. Effect on natural processes and character
a. plants having little or no effect	0
b. delays establishmnent of native species in disturbed sites up to 10 years	3
c. long term (more than 10 years) modification or retardation of succession	7
d. invades and modifies existing native communities	10
e. invades and replaces native communities	15
4. Significance of threat to park resources
a. threat to secondary resources negligible	0
b. threat to areas' secondary (successional) resources	2
c. endangerment to areas' secondary (successional) resources	4
d. threat to areas' primary resources	8
e. endangerment to areas' primary resources	10
5. Level of visual impact to an ecologist
a. little or no visual impact on landscape	0
b. minor visual impact on natural landscape	2
c. significant visual impact on natural landscape	4
d. major visual impact on natural landscape	5
Total possible=50
Urgency
1. Delay in action will result in large increase in effort required for successful control	High
2. Delay in action will result in moderate increase in effort required for successful control	Medium
3. Delay in action will result in little increase in effort required for successful control	Low