Copyright
Lisa Schassberger Roe.

Status review of Arabis fecunda, U.S.D.A. Forest Service, Region 1, Beaverhead National Forest ; prepared by Lisa Ann Schassberger online

. (page 1 of 3)
Online LibraryLisa Schassberger RoeStatus review of Arabis fecunda, U.S.D.A. Forest Service, Region 1, Beaverhead National Forest ; prepared by Lisa Ann Schassberger → online text (page 1 of 3)
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MONTANA
STATE




This "cover" page added by the Internet Archive for formatting purposes



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1990



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HELENA, (MOW TANA 58S20



STATUS REVIEW OF Arabis fecunda

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

BEAVERHEAD NATIONAL FOREST

MONTANA



Prepared by:

Lisa Ann Schassberger , Botanist

Montana Natural Heritage Program

State Library Building

1515 E. 6th Avenue

Helena, MT 59620



1989 Challenge Cost-share Project
January 1990



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This is an abridged report



For the full report please contact:



The Montana Natural Heritage Program

1515 E Sixth Ave

Helena, Montana 59620

406-444-3009



TABLE OF CONTENTS

Page

I. SPECIES INFORMATION

A. CLASSIFICATION 1

B. PRESENT LEGAL OR OTHER FORMAL STATUS 1

C. DESCRIPTION 2

D. GEOGRAPHICAL DISTRIBUTION 3

E. HABITAT 6

F. POPULATION DEMOGRAPHY AND BIOLOGY 8

G. POPULATION ECOLOGY 11

H. LAND OWNERSHIP 11

II. ASSESSMENT AND MANAGEMENT RECOMMENDATIONS

A. THREATS TO CURRENTLY KNOWN POPULATIONS 12

B. MANAGEMENT PRACTICES AND RESPONSE 13

C. RECOMMENDATIONS FOR MAINTAINING VIABLE POPULATIONS. . 13

D. RECOMMENDATIONS FOR FURTHER ASSESSMENT 14

E. SUMMARY 14

III. LITERATURE CITED 15

IV. ELEMENT OCCURRENCE PRINT-OUTS AND MAPS 17

V. PHOTOGRAPHS 3 9

APPENDIX A 45



SPECIES INFORMATION
A. CLASSIFICATION

1. SCIENTIFIC NAME: Arabis fecunda Rollins.

2. COMMON NAME: Sapphire rockcress.

3. FAMILY: Brassicaceae (=Crucif erae, mustard
family) .

4. GENUS: According to Hitchcock et al. (1964),
there are over one hundred species of Arabis in
the Northern Hemisphere. In Montana, there are 12
known species (Dorn 1984, Rollins 1984).

5. SPECIES: Arabis fecunda was first collected in
1975 by Jaculyn Cory along the lower western
flanks of the Sapphire Mountains. This specimen
was subsequently determined to represent a new
species (Rollins, 1984). Arabis fecunda is
endemic to Montana; all of the currently known
locations for this species occur on distinctive,
highly metamorphosed, calc-silicate soils. These
locations are within a 45-mile radius of one
another.

B. PRESENT LEGAL OR OTHER FORMAL STATUS

1. FEDERAL STATUS

a. U.S. FISH AND WILDLIFE SERVICE: Arabis
fecunda is currently included in Category 2
of the U.S. Fish and Wildlife Service Notice
of Review (U.S. Department of Interior 1985),
under consideration for federal listing as a
threatened taxon. Category 2 taxa (= federal
candidate taxa) are those "...for which
information now in possession of the Service
indicates that proposing to list them as
endangered or threatened species is possibly
appropriate, but for which substantial data
on biological vulnerability and threat(s) are
not currently known or on file to support the
immediate preparation of rules."

b. U.S. FOREST SERVICE: Arabis fecunda is
currently included on the Watch list in
Region 1 (Northern Region) of the U.S. Forest
Service. Watch plants include those species,
subspecies or varieties that are not
currently known to occur on National Forest



land, but which are suspected to occur on
such lands owing to the presence of suitable
habitat. Also, these are plants for which
there is concern for population viability
within a given state. If found on National
Forest lands, these taxa would be designated
as sensitive (U.S. Department of Agriculture
1988) . Since the establishment of list, A.
fecunda was confirmed from 5 locations on the
Beaverhead National Forest. Thus, the status
should be changed to sensitive on the U.S.
Forest Service list.

2. STATE: Arabis fecunda is currently listed by the
Montana Natural Heritage Program (Shelly 1989) as
"imperiled in Montana because of rarity" (state
rank = S2 (6-20 occurrences)).

This rank does not currently provide any direct
legal protection for the species.

DESCRIPTION

1. GENERAL NONTECHNICAL DESCRIPTION: Arabis fecunda
is a small, perennial forb, with one to many
clusters of basal leaves, and flowering stems that
reach 3-12 inches in height. The spatula-shaped
basal leaves generally have a smooth margin, and
are 1/2-1 inch in length, and 1/8 inch wide. The
leaves on the flowering stem are smaller and clasp
the stem. A vestiture of dense forked hairs cover
the stems and leaves. Inflorescences are
congested with flowers, each made up of four white
petals 1/4-1/2 inch long, and about 1/8 inch wide.
The nearly erect pedicels may be up to 1/2 inch
long, and bear fruits 1-2 inches long, and about
1/20 inch wide. The fruits are densely hairy, and
each side of the fruit contains a single row of
round seeds (adapted from Lesica 1985) .

2. TECHNICAL DESCRIPTION: Perennial with a simple or
branched caudex, densely pubescent throughout,
with fine dendritically-branched trichomes; stems
erect to somewhat decumbent at base, simple or few
branched, 1-3 dm. high; leaves hoary, dimorphic-
basal leaves petiolate, spatulate to linear
oblanceolate, entire or with a few broad teeth in
the blade area, 1-3 cm. long, 2-4 mm. wide;
cauline leaves sessile, entire or the lower with a
few teeth, oblong, acute, sparingly auriculate to
nonauriculate, 7-20 mm. long; inflorescences
usually congested; sepals oblong, nonsaccate.



densely pubescent, 6-7 mm. long, ca. 2 mm. wide;
petals white to purplish, obovate, not
unguiculate, narrowing gradually from blade to
point of insertion, 9-13 mm. long, 3-5 mm. wide ;
fruiting pedicels erect to slightly divaricately
ascending, straight, 6-10 mm. long; siliques
erect, congested, usually appressed to rachis,
straight to slightly curved inward, 3-5 cm. long,
ca. 1.5 mm. wide, valves densely pubescent,
compressed between seeds; styles ca . 1 mm. long;
seeds in a single row, suborbicular to slightly
longer than broad, narrowly wing-margined all
around, ca. 1.2 mm. in diameter, mucilaginous when
wetted; cotyledons accumbent (adapted from Rollins
1984) .

3. LOCAL FIELD CHARACTERS: The very erect fruits,

and the dense greyish vestiture of branched hairs
on the foliage and fruit, distinguish A. fecunda
from all other Arabis species found in western
Montana (Lesica 1985) .

GEOGRAPHICAL DISTRIBUTION

1. RANGE: All 13 of the currently known populations
of A. fecunda occur in southwestern Montana.
There are four locations for A. fecunda along the
western flanks of the Sapphire Mountains east of
Hamilton, Ravalli County, Montana. Nine
additional locations were recently documented (8
in 1988, 1 in 1989) from small drainages on the
north and east flanks of the East Pioneer
Mountains: Jerry Creek, Quartz Hill Gulch, Canyon
Creek, Cattle Gulch, and Birch Creek.

The global distribution for this species is shown
on Map 1, p. 4. The exact locations are shown on
the maps in Section IV, pp. 31-38. The
populations occur in Beaverhead (7), Ravalli (4),
and Silver Bow (2) counties, Montana.

2. CURRENT SITES: In 1988 and 1989, field surveys of
southwestern Montana revealed nine new populations
of A. fecunda . This brings the total number of
currently documented populations to 13. Five of
the populations occur on lands that are partially
or wholly privately owned, six are on lands
managed by the U.S. Forest Service, and three are
partially or wholly on lands managed by the Bureau
of Land Management and/or State of Montana. The
legal descriptions, elevations, USGS topographic
map names, and locations of sites in Montana are



provided in Section IV, pp. 18-30. Also, the
exact locations are indicated on the maps provided
in Section IV, pp. 31-38.

Recent surveys for A. fecunda include:

Peter Lesica - The Nature Conservancy: May 1985.

J, Stephen Shelly - Montana Natural Heritage
Program: 1-3 June 1988, 6-9 June 1989.

Lisa Ann Schassberger - Montana Natural Heritage
Program: 1-3, 6-7, 13-15 June 1988,
6-9 June 1989.



3.



HISTORICAL SITES: None.



4. UNVERIFIED/UNDOCUMENTED REPORTS: None.

5. AREAS SURVEYED BUT SPECIES NOT LOCATED: The

following areas in Beaverhead County were searched
in 1989, but no additional populations of Arabis
fecunda were located. The actual areas surveyed
were often smaller than the portions of the
sections indicated. The list is organized by
township, range and section number, and all sites
are on Beaverhead National Forest land unless
marked otherwise.



TIS,


R 9W,


Sec


31


SE^


of


SE^


(BLM)


TIS,


RlOW,


Sec


7


NE^


of


NWJ-,


(BLM)


TIS,


RlOW,


Sec


17


SE^


of


NWJj




TIS,


RllW,


Sec


35


SE^i


of


NWi,




TIS,


RllW,


Sec


35


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u\^h




TIS,


RllW,


Sec


35


SE^


of


SEh




T2S,


R 8W,


Sec


6


NE^


of


S^h


(BLM)


T2S,


R 9W,


Sec


12


NW^


of


NWij


(BLM)


T2S,


R 9W,


Sec


20


NW^


of


SW^


(BLM)


T2S,


R 9W,


Sec


5


Central


(BLM)


T2S,


RlOW,


Sec


12


Wij








T2S,


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Sec


2


SE^


of


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T2S,


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Sec


10


SEh


of


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T2S,


RllW,


Sec


15


NEh


of


NWi




T3S,


R 9W,


Sec


8


SEh


of


NW^


(BLM)


T3S,


R 9W,


Sec


7


SWJ-,


of


NE^


(BLM)


T3S,


R 9W,


Sec


12


S!-,


of


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T3S,


R 9W,


Sec


12


s?-.


of


mh




TVS,


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Sec


14


SEh


of


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(BLM)


T8S,


RlOW,


Sec


25


SWJj


of


S^h


(Private)



E. HABITAT: The sites where populations of A.
fecunda occur are distinguished by sandy or
gravelly, light-colored, highly calcareous soils,
derived from metamorphosed calc-silicate parent
materials. These sites are found along small to
large drainages at the edges of mountain uplifts,
where these parent materials have been exposed by
erosion.

Arabis fecunda populations occur in the sagebrush-
grassland zone at locations in Ravalli, Silver Bow
and Beaverhead counties. Additionally, some
populations in Beaverhead County occur in dry
Douglas-fir and lodgepole pine forest zones on
open calcareous slopes. The sites range from
4,600 to 8,000 feet in elevation. Total
vegetation cover at these sites is often low.

1. ASSOCIATED VEGETATION: Arabis fecunda

populations occur most frequently in shrub- and
grasslands, often near open, sparse stands of
Pinus ponderosa (ponderosa pine) , Pseudotsuga
menziesii (Douglas-fir) , or Juniperus scopulorum
(Rocky Mountain juniper) . The common native
species associated with A. fecunda at one or more
sites include:

Achillea millefolium (common yarrow)

Aqropyron spicatum (bluebunch wheatgrass)

Artemisia friqida (fringed sagewort)

Artemisia tridentata (big sagebrush)

Astragalus miser (weedy milk-vetch)

Carex f ilifolia (thread-leaved sedge)

Castilleia pallescens (palish indian-paintbrush)

Cercocarpus ledifolius (curley-leaf mountain

mahogany)

Chrysopsis villosa (hairy goldenaster)

Crepis spp. (hawksbeard)

Crvptantha celosioides (northern cryptantha)

Draba oligosperma (few-seeded draba)

Erigeron compositus (cut-leaved daisy)

Eriogonum umbellatum (sulphur buckwheat)

Festuca idahoensis (Idaho fescue)

Gilia spicata (spicate gilia)

Haplopappus acaulis (cushion goldenweed)

Haplopappus armerioides (thrifty goldenweed)

Koeleria cristata (Junegrass)

Linum perenne (blue flax)

Lithospermum ruderale (wayside gromwell)

Mertensia oblongifolia (oblongleaf bluebells)

Orvzopsis hymenoides (indian ricegrass)

Oxytropis lagopus (haresfoot locoweed)



Penstemon aridus (stiff-leaved penstemon)

Phlox bryoides (moss phlox)

Phlox lonqifolia (long-leaved phlox)

Physaria qeyeri (Geyer's twinpod)

Poa secunda (Sandberg's bluegrass)

Sedum lanceolatum (lance-leaved stonecrop)

Senecio canus (woolly groundsel)

Taraxacum officinale (common dandelion)

Tetradvmia canescens (gray horsebrush)

Townsendia hookeri (Hooker's townsendia)

Additionally, sites on private land. Bureau of
Land Management, and on State of Montana lands
have been invaded by weedy introduced species,
including Centaurea maculosa , Alyssum alyssoides .
and Bromus tectorum .

TOPOGRAPHY: All known populations of Arabis
fecunda are located on well-drained, lower to
upper slopes or ridgelines, at elevations from
4,600 to 8,000 feet. Slope angles range from 10-
40 percent. This species has also been found
growing in small amounts of loose soil, atop rocky
calcareous outcrops.

SOIL RELATIONSHIPS: The four A. fecunda sites
that occur along the west slope of the Sapphire
Mountains occur on a calc-silicate unit of the
Wallace Formation, and are just south of a large
granitic intrusion, the Willow Creek Stock
(Presley 1971) .

The A. fecunda sites along the flanks of and in
the East Pioneer Mountains occur on the upper part
of the Madison Limestone Formation, comprised of
metamorphosed limestone and sandstones, and on the
Threeforks Formation, comprised of grayish-brown
argillaceous limestone (Richards and Pardee 1925) .
These substrates appear similar to those occupied
by populations along the Sapphire Mountains.

The distinctiveness of the soils indicates that
they are a factor in the distribution of A.
fecunda populations.

On a microsite level, A. fecunda may be associated
with cryptogamic soil crusts. Results of a study
at Charleys Gulch (001) and Birch Creek (004) in
Ravalli County are included in Schassberqer
(1988). ^

REGIONAL CLIMATE: The regional climate of
southwestern Montana is characterized by hot "dry



8

summers, and cold, snowy winters. The highest
amounts of precipitation come in the form of rain
in spring.

The weather collection site at Hamilton is
approximately 5 miles west, and 1000 feet lower
than the 4 populations located along the flanks of
the Sapphire Mountains. For the period from 1951-
1980, the July mean temperature was 67.0° F, the
January mean was 25.0° F, and the mean annual
precipitation was 13.11 inches. The long-term
weather station nearest to the populations in the
East Pioneer Mountains is at Divide. This station
is approximately 3.5-20 miles distant from the A.
fecunda sites, and at an elevation of 5,395 feet.
This is up to 2,500 feet lower than some of the A.
fecunda sites. At Divide, the July mean
temperature was 63.3 °F, the January mean was 19.1
°F, and the average annual precipitation was 12.39
inches (U.S. Department of Commerce 1982).

POPULATION DEMOGRAPHY AND BIOLOGY

1. PHENOLOGY: The phenology of the A. fecunda
populations is variable due to the wide range in
elevations at which they are found (4,600 - 8,000
feet) , and differences in their topographical
position. At lower elevation sites or sites with
a more southern aspect, or in dryer habitats, A.
fecunda begins to flower in early May. Mature
fruit is present from late May-June on (Lesica
1985) . At higher elevations, or on sites with a
more northern or western exposure, flowering and
fruiting may extend into early July.

2. POPULATION SIZE AND CONDITION: Populations of A.
fecunda range in size from 75 to 10,000 plants
with an average size of about 1,000. Most of the
populations along the flanks of the Pioneer
Mountains are in good condition. However, the A.
fecunda populations along the flanks of the
Sapphire Mountains have been invaded by various
introduced species. Interspecific competition
with Centaurea maculosa is of primary concern at
these locations. Transects were established at
Charleys Gulch (001) and Birch Creek (004) in
Ravalli County, to gather information on life
history and population trends for A. fecunda .
Reports from an ongoing study of the interactions
between these two species is contained in
Schassberger (1988, 1990). The effects of
Centaurea maculosa invasion on the fecundity of A.



fecunda are also discussed in Hamilton and
Mitchell-Olds (1989) .

Transects were also established in 1989 at two
locations on the Beaverhead National Forest
(Slides, p. 10) . Preliminary data indicate that
fecundity, measured as number of plants fruiting,
percent of plants fruiting, number of fruits per
fruiting plant, and number of fruits per
inflorescence, was lower (in 1989) at Lime Gulch
(012) than at Canyon Creek (013). However, the
Lime Gulch population is approximately 1,000 feet
lower in elevation than Canyon Creek (Oil) , and is
located on the lower eastern flanks of the Pioneer
Mountains in the rain shadow of some of the
highest peaks of the range. Thus, it is likely to
receive substantially less precipitation and have
warmer temperatures than the Canyon Creek
population. This in turn influences the phenology
and possibly the fecundity of the populations.
The data indicate that there needs to be at least
a one to two week delay in reading the Canyon
Creek transects, in order to obtain data
comparable to Lime Gulch. The report on this study
is found in Appendix A, p. 45.

REPRODUCTIVE BIOLOGY

a. TYPE OF REPRODUCTION: Arabis fecunda is a
perennial species that reproduces only by
seed. Individual plants continue to grow
larger each year through branching and
enlargement of the caudex. Early bloom dates
may indicate that A. fecunda is facultatively
autogamous (Lesica 1985) .

b. POLLINATION BIOLOGY: The mechanisms of
pollination are unknown for this species;
however, it may be through selfing and/or by
insects.

c. SEED DISPERSAL AND BIOLOGY: Flowers and
fruits mature acropetally, developing from
the base of the plant to the apex. The often
numerous fruits mature quite quickly.
Although not directly observed, dispersal of
seed is probably similar to that of other
species of Arabis . Valves of the siliques
open from the tip downwards, which expose the
seeds that then drop, or are shaken to the
ground (Lesica 1985) .







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1 3

Online LibraryLisa Schassberger RoeStatus review of Arabis fecunda, U.S.D.A. Forest Service, Region 1, Beaverhead National Forest ; prepared by Lisa Ann Schassberger → online text (page 1 of 3)