A New Population of Aleutian Shield Fern (Polystichum aleuticum C. Christens.) on Adak Island, Alaska

6 Pages·2002·2.6 MB·English

by  Sandra Looman Talbot

American Fern Journal 92(4):288-293 (2002)
A
New
Population of Aleutian Shield Fern
(Polystichum aleuticum
Christens.)
C.
Adak
on Alaska
Island,
Looman
Sandra Talbot
AK
Alaska Science Center, U.S. Geological Survey, 1011 East Tudor Road, Anchorage, 99503
Talbot
Stephen
S.
AK
U.S. Fish and Wildlife Service, 1011 East Tudor Road, Anchorage, 99503
—
We
new
Abstract. report and describe a population of the endangered Aleutian shield fern
[Polystichum aleuticum C. Christens.) discovered on Mount Reed, Adak Island, Alaska. The new
known
population is located at a lower elevation than the other populations, placing the species'
m
known elevational range between 338 and 525 m. The discovery of this population significant
is
because increases the total number of known populations and individuals for the species.
it
The
Aleutian shield fern, Polystichum aleuticum C. Christens., one of the
is
most restricted and rare ferns in North America (Smith, 1985); listed as an
is
it
endangered species (U.S. Department of Interior, 1988). In a circumpolar
was
assessment of the rare vascular plants of the Arctic, the fern classified
lUCN
Red
according to the List threat categories as "endangered** (Talbot ah,
et
1999). The species was first collected by W. Eyerdam, an assistant to Eric
J.
Hulten, in 1932 on Atka Island, one of the Andreonof Islands located in the
center of the Aleutian Island chain, Alaska Eyerdam's holotype
(Fig.
1).
specimen Eyerdam
[W. 1086, 5 July 1932) accessioned at S; isotypes are
is
J.
accessioned CAS, DS, and US. The species was described by
at
first
Christensen Attempts on Atka
(1938). to relocate the original collection site
in years subsequent to the species' description were unsuccessful (Smith and
Davison, 1988). Then, in 1975, a population of the species was discovered, this
time on the northeast arm of Mt. Reed, on Adak Island also of the
(Fig.
1),
Andreonof
Islands of the Aleutian Island chain, Alaska (Smith, 1985). Several
subsequent searches, performed from 1986 to 1988, on various islands of the
Aleutian Island chain (Adak, Kagalaska, Atka and Attn; see Talbot aL, 1995
et
for review) failed to locate additional populations. Finally, in 1988 and 1993,
we
discovered second and on Reed
a third population, respectively, again Mt.
(Talbot et aL, 1995). Three populations comprising approximately 117
known
clumps
individual fern are for the species (Tande, 1989; Talbot et al„
1995).
August
In 1999, genetic studies of Polystichum aleuticum were initiated to
assess the species' relationship lachenense (Hook.) Bedd.
to P. of Asia, as
recommended
While
in Talbot et ah (1995), collecting samples as part of this
known
genetic research, as well as ongoing systematic monitoring of the three
we
populations (Anderson, 1992), discovered a fourth population of
P.
m
aleuticum, located approximately 142 below the two populations found on
TALBOT
& TALBOT; POLYSTICHUM ALEUTICUM ALASKA
IN
289
known
Fig. 1. Location of the four populations of the Aleutian shield fern, Polystichum
Adak
aleuticum, on Mt. Reed, Island, Aleutian Islands, Alaska.
Adak
the northeast arm of Mt. Reed, Island, an elevation of 338 m. As
at
was found on was
the case for the other three sites Mt. Reed, the fourth site at
on The
the base of a steep rock outcrop a northeast-facing slope. slope angles
ranged from 60° 90°. Notably, the located approximately
at this site to site is
m
22 below the lowest of the three previous populations (Population
Fig.
3, 1,
Table in an area considered too treacherous to survey during earlier efforts
1],
due to steep, unstable, slippery slopes. This finding expands the elevational
m
range of aleuticum, placing the species elevations between 338 and
P. at
m
525 [Table Also, notably, the fourth site located on a northeast-facing
is
1).
slope. Climatologic records based on observations from 1950 1982 indicate
to
wind Adak
on predominantly from the west-southwest,
direction averag-
is
November,
ing 10.5 knots per hour, from June to the period of time during
which would snow Department
the habitat likely be free of (U.S. of the Navy,
known
on
1989). Thus, the occurrence of populations northeast-facing
all
to
Table Population characteristics of Polysfichum ahuticum and associated geographical variables.
1.
Latitudo/
Island Location Pop. # Longitude Elevation (m) Aspect # Individuals Year Relocated
N >
Atka unknown, "within view unknown unknown unknown unknown 1932
ofthe village of Atkn""* very rare
Adak Mt. Reed, NE Arm 51° 49.640' N 475.5-525.8 NE 98 1975 Y
1
n
W
176M1.H61' >
N
NE Arm NE Y
Adak Mt. Reed, 2 51° 49.491' 457.2-469.4 14 1988
W
176° 41.776'
NW
N
Adak Mt. Reed, Arm 3 51° 49.9G0' 360.4 NE 5 1993 3 Y
W
176° 44.141'
o
N
Adak Ml. Reed, NE Arm 4 51° 49.378' 338.0 NE 14 + 1999 Y
W
176° 41.733'
>
Christenscn
^ (1038).
<
^ Smith
(1985).
O
r
^ Talbot
at
al. (1995J.
^
Present study.
z
O
o
K3
TALBOT & TALBOT: POLYSTICHUM ALEUTICUM ALASKA
IN 291
slopes suggests habitats supporting populations of P. aleuticum are those of-
fering protection from high winds during growth and reproductive
critical
periods.
new
At least 14 clumps constituted the population; however, due to the
some
inaccessibility of of the vertical rock faces, a complete count of
clumps was number
individual not possible. This therefore underestimates
Among
clumps
the size of the population. the 14 counted, five are associated
with rock grottos; the remaining clumps are found on ledges on steep rock
Unlike the other no clumps were associated with herb meadows.
faces. locales,
Clumps in the grottos and ledges comprise from five to 30 fronds, with all
clumps containing fronds with Clumps associated with steep rock faces
sori.
comprise 12—40 fronds, again with clumps examined containing fronds
all
with sori. However, for safety reasons, not all clumps on vertical rock faces
number The
were examined to determine the of fronds or presence of son.
may
presence on some aleuticum fronds suggests population be
of sori P. this
useful spores were used controlled propagation.
for
if
We new
nomen-
recorded vascular plants associated with the population;
USDA, NRCS
clature follows {2001]. Vascular plants associated with grotto
and ledge clumps were the creeping dwarf shrub Salix rotundifolia Trautv.; the
Anemone
forbs Achillea millefolium L. var. borealis (Bong.) Farw., narcissi-
Campanula
Arnica unalaschcensis lasiocarpa Cham., Conio-
Less.,
flora
L.,
&
Huperzia
selinum gmelinii (Cham. Schlecht.) Steud., chinensis (Christ)
Lycopodium alpinum Pedicularis Platanthera
Czern., L., verticillata L., sp. L.
Polygonum viviparum Polystichum lonchitis Roth, Potentilla
C. Rich., L., (L.j
ex Pursh, and Valeriana acutiloba Rydb.; and the graminoids
villosa Pallas
Poa
Carex macrochaeta C. A. Mey., Carex circinata C. A. Mey., sp. (L.) Roth
and coccinea Richards, Vascular plants associated with
(viviparous) Tofieldia
rock included the forbs Achillea millefolum var. borealis,
vertical faces
Epilobium hornemannii Reichenb., and Viola langsdorfii Fisch. ex Gingins;
Poa and
and the graminoids Carex circinata, sp. (viviparous) Tofieldia
coccinea. Comparison of this of associates from the other sites (Lipkin,
list
1985; Talbot al, 1995) indicates a high degree of similarity in species
et
known
among
composition the four populations.
we
Using hand-held Global Positioning System, recorded precise geo-
a
W. The
population 51° 49.578' N, 176° 41.733'
graphic coordinates as
for this
known
number
new individuals
population increases the of
discovery of
this
We
was while
population discovered accidentally
to 131. note here that this
we were on Adak, and the area would, under normal
disoriented in the fog
very
circumstances, have been considered too treacherous to survey. It is
Reed
possible that additional populations of P. aleuticum inhabit Mt. or
and
nearby mountains, in areas too dangerous to survey without risk of injury,
Adak
we number representing aleuticum on
individuals P.
suggest the of is
surveys undertaken throughout the
extensive
underestimated, despite
likely
from mid-1980s the mid-1990s.
island the to
known
number
because increases the of
This discovery significant
it
is
known
number populations
by approximately 12%, and the of
individuals
292 FERN JOURNAL
three
individuals or populations of this rare and endangered expands
species. also
It
known
the elevational range within which new
future searches
populations
for
should be
targeted.
new
Despite this finding on Adak, however,
P. aleuticum continues be
to
Whil
Aleutian
rocky outcrops similar those on Adak known
to support
that the four
new
populations, without finding any populations. These
islands include:
Adugak,
Aiktak, Amlia,
Buldir, Chagulak, Davidof,
Kasatochi, Khvostof,
Kiska,
and
Nizki, Uliaga islands. Additional surveys by both
authors of Attn Island
in
2000 and Simeonof
Shumagin
Island of the
Island group,
eastern Aleutians, in
1997 new
also failed to yield discoveries of populations. Thus, have
biologists
searched
aleuticum on
for P. 16 islands in the Aleutian chain during
the past
Mt
Adak
Island.
Acknowledgments
Financial support was provided by the Western Area (WAES)
Ecological Services and
Department
of Refuges, Region U.S. Fish and Wildlife and
7, Service, the Alaska Science
Center,
U.S. Geological Survey, Biological Resources We WAES
Division. thank Art Davenport of and
the
staff of the Aleutian Islands Unit, Alaska Maritime NWR, Adak
Island, particularly Jenna Mueller
and
Williams,
Jeff for field support. Terri Morganson
(Division of Realty, U.S. Fish and Wildlife
We
Service) prepared Figure thank Judy
1. R. Gust, Dirk V. Derksen, James Hickey, and an
R.
anonymous
reviewer comments
for valuable on
the manuscript.
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