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Taxonomic and demographic studies of Cirsium longistylum in the Little Belt Mountains, Montana online

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MONTANA




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TAXONOMIC AND DEMOGRAPHIC STUDIES

OF Cirsium lonqistylum

IN THE LITTLE BELT MOUNTAINS, MONTANA



»



U.S.D.A. FOREST SERVICE - REGION 1



LEWIS AND CLARK NATIONAL FOREST



MONTANA



STATE DOCUMEMTS COLLECTION

COT IC 1992

MONTANA STATE LIBRARY

1515 E. 6th AVE.
HELENA, MONTANA 59620



Lisa Schassberger Roe

Montana Natural Heritage Program

1515 E. 6th Ave.

Helena, MT 59620



Challenge Cost-share Project



February 1992



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SUMMARY

Cirsium lonqistylum is a perennial thistle that is endemic to
central Montana. It is primarily known from Little Belt
Mountains, where it is nearly ubiquitous within mesic to moist
meadow and stream terrace sites. A summary of the status of this
species can be found in Schassberger and Achuff (1991) and
Schassberger (1991) .

In 1991, Cirsium longistylum was removed from the Watch List of
sensitive species for Region 1 of the U.S. Forest Service due to
abundance. However, because it is a state endemic known from a
limited area (albeit common in that area) , and may be threatened
by a weevil introduced as a biological control agent (used in an
effort to limit the spread of the introduced Carduus nutans ) , it
continues to be categorized by the U.S. Fish and Wildlife Service
as C2 (U.S. Department of the Interior 1990). Cirsium
lonqistylum is also ranked by the Montana Natural Heritage
Program (Achuff 1991) as an S3 species; "rare in Montana (21+
occurrences)."

Morphological variation in some populations has led to questions
about possible hybridization with other Cirsium species, and
about the systematic status of C. lonqistylum . Numerous
collections were made during the 1991 field season, and sent to
Dr. A. Cronquist (Botanist, New York Botanical Garden) for
review. Based on this material. Dr. Cronquist (1992) stated that
he now felt that "C. lonqistylum was a "good" species of limited
distribution in Montana." He also felt that "it probably
hybridizes with C. hookerianum and possibly C. scariosum Nutt.",
and that "hybrids were best identified in the field." Dr.
Cronquist annotated the specimens from the population at Neihart
as C. hookerianum Nutt., and they will be considered as such in
the demographic studies. In light of the results of the
morphological overview, it would be appropriate to use techniques
of electrophoresis to support the hybridization hypotheses.

Permanent plots were set up at three sites (Russian Creek, Kings
Hill, Neihart) in 1990 to study life history characteristics of
C. lonqistvlum . As stated above, the population at Neihart will
now be considered as C. hookerianum . Changes in population
numbers from 1990 to 1991 within study plots were found to be a
result of: loss of plants which had flowered in the previous
year, loss of plants at the rosette stage, and recruitment rates.
Over this short period, population sizes and number of plants
flowering fluctuated, but only further study will determine if
this is normal for the species.

At Kings Hill in 1991, disturbance of the soil by rodents
eliminated previously established rosettes, but appeared to aid
in the germination of seeds as evidenced by the numerous
seedlings present. At Neihart, many plants (31%) were grazed,
either lightly or heavily. How grazing ultimately affects the
ability of these rosettes to reach maturity will be revealed
through continued monitoring.



TABLE OF CONTENTS

PAGE

SUMMARY i

STATUS 1

FIELD SURVEY 1

TAXONOMIC STUDIES 1

INTRODUCTION 1

METHODS 2

RESULTS AND CONCLUSIONS 3

DEMOGRAPHIC MONITORING TRANSECTS 3

METHODS 3

RESULTS AND CONCLUSIONS 4

RECOMMENDATIONS 12

LITERATURE CITED 13

DEMOGRAPHIC MONITORING DATA 14



STATUS

SCIENTIFIC NAME: Cirsium lonqistylum Moore & Frankton.

COMMON NAME: long-styled thistle.

FEDERAL STATUS: 02

FOREST SERVICE STATUS: None. In 1991, Cirsium lonqistylum
was removed from the Watch List of sensitive species for
Region 1 of the U.S. Forest Service due to abundance.

FIELD SURVEY

While making collections of C. lonqistylum for the taxonomic
study in 1991, a brief survey of the Highwood Mountains was
completed. The introduced species Cirsium arvense and C. vulqare
were both present here, but C. lonqistylum was not observed. It
is possible that C. lonqistylum is associated with the calcareous
soils of the Little Belt, Big Belt and Castle Mountains. The
Highwood Mountains on the other hand, are volcanic centers that
erupted shonkinite (similar to basalt, but greatly enriched in
potassium) and other rocks about 50 million years ago (Alt and
Hyndman 1986) .

TAXONOMIC STUDIES

INTRODUCTION: Several Cirsium collections from the Little
Belt Mountains and the Sawtooth Range were sent to Dr.
Arthur Cronquist (a specialist in the Asteraceae=Sunf lower
Family) for verification in the winter of 1990-1991. The
Sawtooth Range collection, Schassberqer (402) . NY, was
verified as C. hooker ianum . However, of the two sent from
the Little Belt Mountains ( Schassberqer (403) , NY, Belt
Park; Schassberqer (397) , NY, Thornquist Gulch) , Dr.
Cronquist (1991) felt that the Thornquist Gulch collection
"would seem to loe C. lonqistylum . " whereas the collection
from Belt Park "looks to me like C. hooker ianum . " He went
on to state that "I included C. lonqistylum , with some
reluctance, in the single-volume flora for the Pacific
Northwest, but I was uneasy about it then and I remain so
now." Close examination by professional botanists of plants
from the same population had often revealed a great deal of
variability in the expansion of the involucral bract, a key
character used in the identification of C. lonqistvlum .

In the hopes that a more definitive conclusion might be
reached, it was determined that a large number of specimens
(preferably with duplicates) from sites across the range of
the species should be sent to Dr. Cronquist for careful
examination.



METHODS: Collections of C. longistylum were made by the
author from twelve locations in the Little Belt and Big Belt
mountains, and one collection of C. hookerianum from the
Sawtooth Range in 1991. Duplicates were taken at most
sites, however, slow drying caused molding in some cases so
that only five locations had one (or two) duplicate
specimens. These specimens, along with three collected in
1990, and four (one Cirsium hookerianum from the Sawtooth
Range, and three Cirsium lonqistylum from the Little Belt
and Castle mountains) collected by Dana Field and Wayne
Phillips (Lewis & Clark National Forest) were sent to Dr.
Arthur Cronguist for verification in December of 1991.

RESULTS AND CONCLUSIONS: Based on this material. Dr.
Cronguist (1992) stated that he now felt that "C.
lonqistylum was a "good" species of limited distribution in
Montana." He also felt that "it probably hybridizes with C.
hookerianum and possibly C. scariosum Nutt.," and that
"hybrids are best identified in the field." Collections and
subseguent annotations are as follows:

Submitted as Cirsium hookerianum Nutt.
Roe. Lisa, S. (464) 1991., NW side of Flesher Pass
Field. D. (14) 1991., Sawtooth Range, Slide Rock Point

Submitted as Cirsium lonqistylum Moore & Frankton

Schassberqer. Lisa A. (403) 1990. Little Belt Mtns. Belt Park
Annotated JAN 1992 by A. Cronguist as C. hookerianum Nutt.

Schassberqer. Lisa A. (409) 1990. Little Belt Mtns., Hay Coulee

Roe. Lisa. S. (465) 1991. Little Belt Mtns., Neihart Cemetery

Roe. Lisa. S. (466) 1991. Little Belt Mtns., Harley Creek
Possible hybrid (Cronguist 1992)

Roe. Lisa. S. (467) 1991. Little Belt Mtns., Kings Hill Pass
Possible hybrid (Cronguist 1992)

Roe. Lisa. S. (468) 1991. Little Belt Mtns., Deadman Creek

Roe. Lisa. S. (469) 1991. Little Belt Mtns., Birch Creek

Roe. Lisa. S. (470) 1991. Big Belt Mtns., Duck Creek Pass

Roe. Lisa. S. (472) 1991. Little Belt Mtns., Hay Canyon



Roe, Lisa, S. (473) 1991. Little Belt Mtns., Onion Park

Annotated JAN 1992 by A. Cronquist as C. hookerianum Nutt.

Roe, Lisa, S. (474) 1991. Little Belt Mtns., O'Brien Park

Schassberqer, Lisa A. (401) 1990. Little Belt Mtns., O'Brien Park

Field, D. (13) 1991. Little Belt Mtns., Lamb Creek

Field D. (16) 1991. Castle Mtns., Pasture Gulch

Phillips H.W. 9910808-3) 1991. Little Belt Mtns.

It is of interest to note that in general, the specimens

determined as C. hookerianum came from habitats that were

moist to wet, whereas the rest of the specimens were

collected from more mesic sites. The exception to this rule

is the collection from Kings Hill (a mesic site) that was
determined as a potential hybrid. However, this site has
been extensively disturbed by road improvement activities.

In light of the results of the morphological overview, it
would be appropriate to use techniques of electrophoresis to
support the hybridization hypotheses and delimit the range
of the species.

The collections denoted "Belt Park" in the list above were
from the plot referred to as Neihart in the demographic
monitoring studies.

DEMOGRAPHIC MONITORING TRANSECTS

During 1990, three permanent monitoring transects were
established in what were thought to be populations of C.
lonqistylum on the Lewis and Clark National Forest. As stated
above in the taxonomic discussion. Dr. Cronquist (1992) annotated
the Neihart population as C. hookerianum , and it will be
referenced as such throughout the rest of the report.

The purpose of these transects is to provide more detailed data
on the life history and population dynamics of C. lonqistylum .
Data on survivorship and reproduction are important for
understanding the biology of plants with limited distributions,
especially when attempting to ensure their long-term preservation
(Palmer 1987, Massey and Whitson 1980).

METHODS: The locations and the geographic details and
methods used to establish the three plots are contained in a
report by Schassberger and Achuff (1991). As in 1990,
individuals were placed in size classes that appeared to



best relate to age. Additional categories were added as
necessary in 1991. These included:

? - Rosettes or plants that had been recorded in the
previous year but were not relocated in the current year.
When present, possible causes of disappearance are noted.

Gone - Plants that were recorded as dead in the previous
year, and which had decomposed or disappeared by the current
year. (For example: Plants that had flowered in 1989, were
recorded as dead in 1990 (dead flowering stalks were still
visible) , and as gone in 1991 (when stalks and leaves had
disappeared) .

Grazed - Many of the rosettes, especially at the Belt Park
site, had been grazed. It was thought that this might have
an effect on the ability of the plant to produce and store
enough energy to eventually flower. Information on grazing
was recorded as follows.

Grazed heavily - Plant was significantly reduced in
size, at least two leaves had been removed.

Grazed - Plants that had a leaf or portion of a leaf
removed .

Finally, general observations about the site and plants were
noted where possible. As before rosette=individual that has
only whorl (s) of leaves, flowering plants=individuals that
are reproductive.

Raw data (1990-1991) recorded for each site are provided in
Section VI., Demographic Monitoring Data, pp. 14-23.

RESULTS AND CONCLUSIONS: Plot data for the three sites are
summarized in Table 1, p. 5 (Russian Creek), Table 2, p. 7
(Kings Hill), and Table 3, p. 9 (Neihart) . Portions of this
information are also represented graphically in Figures 1,
2, and 3, pp. 6, 8 and 10, respectively. In the tables,
population growth rate (negative or positive) was calculated
as the change (+) in the number of individuals from year 1
to year 2, divided by the number of individuals present in
the plot in year 1, times 100.

Population sizes decreased at Neihart and Russian Creek from
1990 to 1991, and increased substantially at Kings Hill.
The total number of individuals within the plots was reduced
at Neihart by 26 percent and at Russian Creek by 33 percent
between 1990 and 1991, while the number of individuals
increased at Kings Hill by 54 percent during the same time
period. In 1991, the density of plants varied from 0.18



TABLE 1. Summary of life history monitoring data for Cirsium

lonqistvlum at Russian Creek, Little Belt Mountains, Lewis
and Clark National Forest, 1990-1991. (Percentages are
rounded up or down to the nearest whole number.)



RUSSIAN CREEK (elevation 6520 ft)



Plot radius 37 ft (11.3 m)



Observation Date



1990/07/27



1991/08/01



Total # plants (dead or
alive) observed



106



Total # live rosettes

and plants of current year

Percentage change from
the previous year



107



72
-33X



New recruits (as a
percent of all plants)

Density of live
(plants/m )



0.24



23 (32X)
0.18



# small rosette plants
(percent of small rosettes)

# medium rosette plants
(percent of medium rosettes)

# large rosette plants;
(percent of large rosettes)

total a plants at

rosette stage; (percent of

plants at rosette stage)

# plants flowering;
(percent of plants flowering)

mean # of heads
open or unopened
per flowering plant
+ SD, n

Total # rosettes
observed to be dead

Total # of rosettes not
relocated presumed dead

Total # dead or not relocated
rosettes; (as a percentage
of all live plants present in
the previous year)

Total # of plants

that had flowered in the

previous year and are now dead

Total # of plants not \

relocated that had flowered the
previous year and are presumed dead

Total number of dead or not relocated
(flowering and rosette) plants; (as a
percentage of all live plants present in
the previous year



26 (24X)


24 (33%)


23 (21%)


25 (35%)


20 (19X)


19 (26%)


69 (64X)


68 (94X)


37 (35X)


4 (6X)


16.4 + 8.4
n = 37


13 + 16.1
n = 4




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19




20 (19%)



33



57 (53%)



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TABLE 2. Summary of life history monitoring data for Cirsium

longistylum at Kings Hill, Little Belt Mountains, Lewis and
Clark National Forest, 1990-1991. (Percentages are rounded
up or down to the nearest whole number.)



KINGS HILL (Elevation 7880 ft)



Plot radius 15 ft (4.6 m)



Observation Date



1990/07/30



1991/08/02



Total # of plants

(dead or alive) observed

Total # plants of
current year plants
recorded

Percentage change from the
previous year

New recruits; (as a percent of
all plants)

Density of live (plants/m )

a small rosette plants;
(percent of small rosettes)

# medium rosette plants;
(percent of medium rosettes)

# large rosette plants;
(percent of large rosettes)

total # plants at

rosette stage; (X of plants

at rosette stage)

# plants flowering;
(percent of plants flowering)

mean U of heads
open or unopened
per flowering plant
+ SD, n

Total # rosettes
observed to be dead

Total # of rosettes not
relocated and presumed dead

Total # dead and not relocated
rosettes; (as a percentage of all
live plants present in the
previous year)

Total # of plants

that had flowered in the

previous year and are now dead

Total # of plants not
relocated that had flowered the
previous year and are presumed dead

Total number of dead or not relocated
(flowering & rosette) plants; (as a
percentage of all live plants present
in the previous year)



205



113


174




54X




133 (76%)


1.7


2.6


31 (27X)


141 (81X)


37 (337.)


24 (14X)


13 (12X)


9 (5%)


81 (71X)


174 (100X)



32 (28X)



10.5 + 7.7
n = 37



(OX)



5
35

40 (35X)

26



72 (64%)



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TABLE 3. Summary of life history monitoring data for Cirsium

hookerianum at Neihart, Little Belt Mountains, Lewis and
Clark National Forest, 1990-1991. (Percentages are rounded
up or down to the nearest whole number.)



NEIHART (Elevation 6960 ft)



Plot radius 15 ft (A. 6 m)



Observation Date



1990/07/30



1991/08/01



Total # of current
year rosettes
and plants

Percentage change from the
previous year

New recruits (as a percent
of all plants)

Density (plants/m )

# small rosette plants
(as a % of al I plants)

# medium rosette plants
(as a % of all plants)

a large rosette plants
(as a % of all plants)

# plants at
rosette stage

(7. of plants at rosette
stage)



U2


105




-26%




44 (42X)


2.2


1.6


42 {30X)


50 (47X)


54 (38%)


38 (36X)


22 (16X)


17 06X)


118 (83%)


105 (100X)



# plants flowering

(percent of plants flowering)



24 (17%)



(0%)



mean it of heads
(open or unopened)
per flowering plant
(1 SD, n)



14.6 + 5.8
n=24



Total # rosettes
observed to be dead
in 1991



Total # of rosettes

not relocated and presumed dead



54



Total # dead or not relocated
rosettes; (as a percentage
of all live plants present in
the previous year)



57 (40%)



Total # of plants

that had flowered in the

previous year and are now dead

Total # of plants not

relocated that had flowered in the

previous year and are presumed dead



17



Total number of dead or not relocated
(flowering and rosette) plants present;
(as a percentage of all live plants
present in the previous year)



81 (57%)



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1

Online LibraryLisa Schassberger RoeTaxonomic and demographic studies of Cirsium longistylum in the Little Belt Mountains, Montana → online text (page 1 of 2)