NORTHWARD RANGE EXTENSION IN FLORIDA OF THE INVASIVE FERN LYGODIUM MICROPHYLLUM (LYGODIACEAE)

3 Pages·2003·1.9 MB·English

by  Robert W Pemberton

NORTHWARD RANGE
EXTENSION FLORIDA
IN
OF THE FERN
INVASIVE
MICROPHYLLUM
LYGODIUM (LYGODIACEAE)
Pemberton
Robert W.
known
Lygodium microphyllum (Lygodiaceae), as Old World climb-
(Cav.) R.Br.
swamps
most weed and other moist
ing considered be the serious of
fern, to
is
&
The weed
(Pemberton severe
southern Florida Ferriter 1998). a
habitats in is
problem because dominates and displaces native vegetation, spreading rap-
is
it
The
and lacks adequate or affordable control measures. fern is native to the
idly,
Old World subtropics and tropics (Pemberton 1998), and was first found to be
Martin County 1965 (Beckner Since then, the plant has
naturalized in in 1968).
spread to infest numerous susceptible habitats in all the Florida counties south
Lake Okeechobee. The weed covered an estimated
of the northern shore of
ha 1999 comm.), and has expanded con-
40,500 in Florida as of (A. Ferriter pers.
siderably since then. For instance, the infestation in Everglades National Park
was estimated to occupy 810 ha in December 2002, but ca. 4,050 ha in August,
and
spraying with herbicides (T Pernas Taylor
2003, despite aggressive aerial
J.
much
comm.). The occurs more sporadically north of Lake
fern
pers.
known
Okeechobee but becoming more abundant. Prior to this report, the
is
County
northern limits of microphyllum were near Nalcrest in southeast Polk
L.
&
and southern Brevard County (Pemberton Ferriter 1998), both at
at a site in
The County
ca. 27'' "50' latitude. Brevard population probably recent, de-
is first
tected in 1997 (specimen sent to and confirmed by the author by M.A. Poole),
County was when
but the Polk population present
at least since 1979, a her-
barium sample was
(Willson FLAS!)
353, collected.
Duringjanuary 2003, an unrecognized population microphyllum was
of
L.
swamp
examined
cypress Odando. This
in a east of 28°30'42"N, repre-
at
site,
lioiidstw UK upi\pKsstieetiunl<s TdAodiumciishchumCD formmg
ihc Rich
luj,(. si Ills tonsistnigol li\mg mtcrt wined fionds layered over dead but per-
m
siiandsol stems The hke
sisteiu rachisC large size of these skirts, those the
).
long-cstabhshcd populations weed southern
of the in Florida, indicates that
his Oi aiigc ounty population not new. Lygodium microphyllum was found
C is
I
Lluring vegetation analysis wetland during and
a ol this 1989, 1990, 1991, but
Sw Camp
misidcntilicd as L}oodniiu jajx^iiHum (Thunb.) Swartz
Dresser
(L.
,
COM
and
\kl\ee Inc.. here loith Inc unpublished reports). Lygodiumjaponicum
.
Is the 01 her invasive climbing lern that has naturalized in Florida, and the two
species are often conlused. Lygodium japonicum rarely occurs deeper wet-
in
suth swamps, L
land.s as but can't survive constant standing water
like
it
)ophyUu)n. Lygodium japonicum has pinnules
Mile sterile ("leaflets") that are
lobed or dissected, whereas microphyllum only occurs wet
L. at sites in Florida
and
has pinnules
sterile that are usual ly unlobed. Furthermore, japonicum
L.
is
common
in northern and central Florida (and occurs widely Southern
in the
L
states), but microphyllum occurs, with few exceptions such
a as this one, in
southern
the third of Florida.
The occurrence newly L
of this recognized population of microphyllum
in
he northern part of Orange County, and persistence almost dem-
its for 15 years,
t
onstrates the plants
ability to tolerate significant single-night This
freezes.
CDM
which was
population, found by
first Inc. staff duringjulyl989, survived
when
the 1989 Christmas freeze temperatures dropped during
to -2.5-5.50C the
three day period (Orlando International Airport Weather #6628
Station
On
and
records). all three dates (Dec. 23, 24, the daytime temperatures
25),
km
climbed above The
freezing. airport is ca. 13 to the southwest of the popula-
more
This northerly occurrence
tion. indicates that the endure
plant's ability to
lower temperatures of short duration greater than previously recognized. The
is
may
observations suggest microphyllum
that L. be able to colonize additional
and
areas in central Florida, probably northward, especially along the
relatively
mild The
east coast of the state. fact that microphyllum has not come domi-
L. to
Orange County swamp,
nate the cypress despite being there for ca. 15 or more
years, suggests that the weed is not as aggressive in central Florida as it is in
and
southern Florida. The ability of this fern to colonize persist in central
Florida, in USDA-Cold Hardiness Zone 9 (Cathey 1990), as well that wetlands
The
southern Texas and Louisiana are chmatically suitable for the weed. plant
in
many
produces numbers spores and occurs on oceanic islands within
large of
may
native range both of which suggest that be able to reach these areas
its it
&
wind-borne spores (Pemberton Ferriter 1998). Because this fern's ga-
via
its
metophytes are self fertile (Lott et al. 2003), only one spore is needed to start a
may weed
new infestation. Biological control have the potential to control this
and mite herbivores currently
(Pemberton, 1998); a suite of specialist insect is
being evaluated (Pemberton et al. 2002; Goolsby et al. 2003).
ACKNOWLEDGMENTS
CDM
wish thank Lee and Swartz, Maitland, Florida, for provid-
to B. L. Inc.,
I
J.
CDM
swamp on
and information from reports the
ing access the infested for
to
Amy
Water Manage-
monitoring South Florida
vegetation the Ferriter,
at site.
ment and Tony Pernas and Jonathan Taylor, Everglades National Park,
District
USDA-ARS,
microphyllum abundance. Paul
kindly shared estimates of Pratt,
L.
and W.
Lauderdale, read and improved an earlier draft of this note, Forest
Ft.
Kathy
Howard, Univ Florida, Davie, wrote the Spanish language abstract. Burks,
and
Department Environmental Protection, Tallahassee, Colette
Florida of
Survey FL provided knowledgeable reviews
Geological Gainesville,
Jacono,
U.S.
me
manuscript which helped produce better final version.
of the for Sida,
escaped Amer. hern
Lygodium microphyllum, another tern Florida.
1968. in
Beckner, J.
J.
58:93-94.
USDA
U5DA zone map. Misc. Publ, 475.
H.M. 990. plant hardiness Agric. Res. Ser.
Cathey,
1
1
Government Washington, DC.
Printing Office,
U.S.
and
and R.W 2003. Exploratory surveys Australia Asia
Wright Pemberton. in
Goolsby, J.A.J.
for natural enemies of Lygodium microphyllum. Biol. Control 28:33-46.
and The reproductive biology of
Lott, M.S., J.C. Volin, R.W. Pemberton D.F. Austin. 2003.
Lygodium microphyllum and Ljaponicum (Schizaeceae): implications for invasive po-
44-1
Amer.
Bot. 90:11 52.
tential.
J.
and 1998. Old World climbing fern (Lygodium microphyllum), a
Pemberton, R.W. A. Ferriter.
dangerous weed Amer. Fern 65-75.
invasive Florida. 84:1
in J.
management Old World
1998.The potential of biological control for the of
Pemberton, R.W.
Amer
76-82.
climbing fern {Lygodium microphyllum) in Florida. Fern J. 84:1
Pemberton, R.W„ Goolsby, and Wright. 2002. Old World climbing fern {Lygodium
J.
J.
microphyllum Van Driesche, Blossey and M. Hoddle,S. Lyon, and R.
(Cav.) R.Br.). In: R. B.
US
Reardon, eds. Biological control of invasive plants in the eastern United States. For-
Morgantown, West
Technology Team-2002-04,
Service Forest Health Enterprise
est