This description provides characteristics that may be relevant to fire ecology, and is not meant for identification. Keys for identification are available (e.g. [27,43,44]).
Japanese climbing fern fronds are from 3.3 to 100 feet (1-30.5 m) in length [1,3,27], and small-leaf climbing fern fronds grow to 90 feet (27 m) long [15]. In Japanese climbing ferns, pinnae (groups of leaflets) are up to 12 inches (30 cm) wide, and are subdivided into 2 or 3 pinnules (leaflets) up to 3 inches (8 cm) long and 6 inches (15 cm) wide [27,28]. Small-leaf climbing fern pinnae are 2 to 5 inches (5-13 cm) long with several pairs of pinnules [15]. Fertile pinnules of small-leaf climbing fern are fringed with tiny lobes of enrolled leaf tissue along the margin, which cover the reproductive tissues [15]. Japanese climbing fern sporangia are borne on narrow, fingerlike segments of the pinnae [3].
Japanese climbing fern Small-leaf climbing fern ©John M. Randall/The Nature Conservancy ©Mandy Tu/The Nature Conservancy
In addition to their photosynthetic and reproductive functions, adult climbing fern fronds are analogous to the twining shoots of flowering plants, spreading along the ground, over shrubs, or climbing by twining around other structures, such as trees and other vines [3,15,18,27]. Twining growth is indeterminate and occurs at a steady rate [18,19,26]. Annual height increase averaged (± SE) 3.81 ± 0.07 feet (1.16 ± 0.02 m) for small-leaf climbing fern growing on infested trees in Jonathon Dickinson State Park and Big Cypress Seminole Indian Reservation, southern Florida [38].
Climbing ferns are rhizomatous [3,27]. Rhizomes grow 0.4 to 1.2 inches (1-3 cm) below soil surface [18].
Climbing ferns are evergreen in subtropical environments [5].
Japanese climbing fern is native from India, east through southeastern Asia and China to Japan and Korea, and south to eastern Australia (Singh and Panigrahi 1984 as cited in [5]). North American establishment was first recorded in the early 1900s in Georgia (Clute 1903 as cited in [25]). Japanese climbing fern is now introduced throughout the southeastern United States from Texas and Arkansas to North Carolina, and also in Puerto Rico (Proctor 1989, Nauman 1993 as cited in [5]). It is considered a "problem weed" from central Florida west across the southern half of the Gulf states [28].
Small-leaf climbing fern is native to tropical and subtropical areas of Africa, southeastern Asia, northern and eastern Australia, and the Pacific islands (reviewed by [5,24]). In North America it is found in southern and central Florida [21,44]. Large parts of the Caribbean, Central and South America, and perhaps coastal areas of southern Louisiana and Texas may also be vulnerable to small-leaf climbing fern invasion [10,23,25]. Small-leaf climbing fern was first collected from the wild in southern Florida in 1960 [15]. As of 2005, Florida Plant Atlas [42] showed small-leaf climbing fern distribution in southern Florida from coast to coast and as far north as Hillsborough and Brevard counties. Ecological/climate modeling indicates small-leaf climbing fern could become established throughout most of southern Florida, with northern distribution extending furthest along the coasts [10].
Ferriter [5] reviewed the history of climbing fern invasion in the southeastern U.S.
The Flora of North America provides distribution maps of climbing ferns.
The following biogeographic classification systems demonstrate where Japanese climbing fern (labeled with the abbreviation J) and small-leaf climbing fern (O) could potentially be found based on floras and other literature, herbarium samples, and confirmed observations. Precise distribution information is unavailable. In general, predicting distribution of nonnative species in North America is difficult due to gaps in understanding of their biological and ecological characteristics, and because they may still be expanding their range. Therefore, these lists are speculative and may be imprecise.
There are suggestions that small-leaf climbing fern is "tolerant of fire" (reviewed by [5]) and that Japanese climbing fern is "promoted" by fire (reviewed by [40]), but no details are provided.
Fire adaptations: Although it is likely that climbing ferns can regenerate following fire (see Plant Response To Fire), as of this writing (2005) there are no published descriptions of climbing fern fire adaptations.
FIRE REGIMES: Climbing ferns may alter FIRE REGIMES by providing ladder fuels, leading to greater incidence of crown fire in communities that are ill-adapted to crown fire (reviewed by [20]).
The following table provides fire return intervals for plant communities and ecosystems where climbing ferns are important. For further information, see the FEIS review of the dominant species listed below. This list may not be inclusive for all plant communities in which climbing ferns occur. Find further fire regime information for the plant communities in which these species may occur by entering the species' names in the FEIS home page under "Find FIRE REGIMES".
Climbing fern spp.** Community or Ecosystem Dominant Species Fire Return Interval Range (years) J bluestem-Sacahuista prairie Andropogon littoralis-Spartina spartinae 22] O mangrove Avicennia nitida-Rhizophora mangle 35-200 [20] J sugarberry-America elm-green ash Celtis laevigata-Ulmus americana-Fraxinus pennsylvanica <35 to 200 J Atlantic white-cedar Chamaecyparis thyoides 35 to >200 J yellow-poplar Liriodendron tulipifera <35 [40] JO Everglades Mariscus jamaicensis <10 JO melaleuca Melaleuca quinquenervia <35 to 200 [20] J shortleaf pine Pinus echinata 2-15 J shortleaf pine-oak Pinus echinata-Quercus spp. <10 JO slash pine Pinus elliottii 3-8 JO slash pine-hardwood Pinus elliottii-variable <35 [40] JO South Florida slash pine Pinus elliottii var. densa 1-15 [20,33,40] JO longleaf-slash pine Pinus palustris-P. elliottii 1-4 [20,40] J pocosin Pinus serotina 3-8 J pond pine Pinus serotina 3-8 J loblolly pine Pinus taeda 3-8 J loblolly-shortleaf pine Pinus taeda-P. echinata 10 to <35 J Virginia pine Pinus virginiana 10 to <35 J Virginia pine-oak Pinus virginiana-Quercus spp. 10 to <35 J sycamore-sweetgum-American elm Platanus occidentalis-Liquidambar styraciflua-Ulmus americana <35 to 200 [40] J eastern cottonwood Populus deltoides <35 to 200 [22] J mesquite Prosopis glandulosa <35 to <100 [17,22] J oak-hickory Quercus-Carya spp. <35 [40] J oak-gum-cypress Quercus-Nyssa-spp.-Taxodium distichum 35 to >200 [20] J southeastern oak-pine Quercus-Pinus spp. <10 J white oak-black oak-northern red oak Quercus alba-Q. velutina-Q. rubra <35 J post oak-blackjack oak Quercus stellata-Q. marilandica <10 J black oak Quercus velutina <35 J live oak Quercus virginiana 10 to<100 [40] JO cabbage palmetto-slash pine Sabal palmetto-Pinus elliottii <10 [20,40] J southern cordgrass prairie Spartina alterniflora 1-3 [22] JO bald cypress Taxodium distichum 100 to >300 JO pond cypress Taxodium ascendens <35 [20] *fire return interval varies widely; trends in variation are noted in the species reviewAs of this writing (2005) there is very little published information about fire management and climbing ferns. Roberts [30] indicated that "fire alone will not control" small-leaf climbing fern, but no further details were provided. Stocker and others [36] burned small-leaf climbing fern with a propane torch and indicated that "recovery" was imminent. Citing a personal communication, Ferriter [5] reported that prescribed fire, alone and in combination with 2,4-D herbicide application, was not effective at controlling Japanese climbing fern in northern Florida pine plantations. More detailed research is needed to determine how climbing ferns might respond to broadcast burning or wildfire under varying burn conditions, intervals, seasons, etc.
Climbing fern presence may instigate changes in fire behavior. Small-leaf climbing fern presence in southern Florida forests has been associated with greater incidence of crown fire, due to an increase in ladder fuels. Also, burning mats of small-leaf climbing fern may be lofted by convection and ignite spot fires downwind from the main fire (reviewed by [20]). There are also suggestions that climbing fern presence in forest canopies may carry fire through wet areas that would otherwise present a boundary to fire spread (reviewed by [15]).
In the southeastern U.S. Japanese climbing fern can be found in swamps, moist woods, and riparian habitats, and is frequently associated with disturbance [3,27,43,44]. Small-leaf climbing fern occurs in a variety of forested and nonforested sites in southern Florida, including hardwood hammocks, cypress swamps, savannas, woodlands, marshes, and wet prairies [25,43,44]. A review by Ferriter [5] indicated that, in its native range, small-leaf climbing fern is "found in a variety of habitats including mesic forests, rain forest, and open swampy areas" (Serizawa 1975, Edie 1978, Singh and Panigrahi 1984 as cited in [5]), and Japanese climbing fern is "native to the edges of forests, open forests, and secondary forests" (Serizawa 1975, Edie 1978, Singh and Panigrahi 1984 as cited in [5]).
Climbing ferns do not seem well-adapted to extremely dry habitats or soils with exceptionally long hydroperiods (reviewed by [5]). Nauman and Austin [21] reported that small-leaf climbing fern is "confined to wet, disturbed sites...found only near canals, rivers, ditches, in disturbed swamps, and other sites which have standing water for a large part of the year." Volin and others [38] reported that small-leaf climbing fern presence within study sites in Big Cypress National Preserve and Big Cypress Seminole Indian Reservation, southern Florida, was significantly (p<0.05) correlated to hydrology, "coinciding with a wet, but not permanently inundated environment."
Aboveground portions of climbing ferns are killed by frost, but roots may be protected [5,25,41]. This is particularly true, at least for small-leaf climbing fern, when roots are growing in standing water (reviewed by [41]). Japanese climbing fern foliage is killed by freezing temperatures, but browned fronds often remain draped in shrub and tree canopies enabling new growth easier access to the same habitat once favorable temperatures for growth resume [5]. A modeling exercise conducted by Goolsby [10] indicated that, although small-leaf climbing fern appears intolerant of freezing temperatures, it may be tolerant of near-freezing temperatures if daytime maximums are warm. Pemberton and Ferriter [25] suggested that small-leaf climbing fern may eventually extend its range into portions of northern and central Florida that are within USDA Plant Hardiness Zone 9b [12]. However, its occurrence may be limited by insufficient heating degree-days. Although damage from cold, but above-freezing temperatures may not be apparent, reduced growth during prolonged periods of cool weather may limit small-leaf climbing fern competitiveness [10].
Impacts: Although there are few studies documenting the impacts of climbing ferns on native plants and ecosystems in the southeastern U.S., their invasion is likely to have deleterious effects. Nauman and Austin [21] reported that climbing ferns are established, persistent, and spreading in Florida, Japanese climbing fern in the north and small-leaf climbing fern in the south. A review by Ferriter [5] suggested that climbing ferns don't require "human disturbance in order to spread and become established."
Most accounts of impacts associated with climbing fern invasion (e.g. reviews by [1,15,16,21,25,41]) describe interference with native plants due to a prodigious growth habit. Climbing ferns can produce thick mats along the ground, severely reducing native ground cover. A review by Wood [41]) indicated that small-leaf climbing fern can form mats up to 4 feet (1.2 m) thick. They also climb into forest canopies, shading trees and shrubs that it covers, weakening or killing them, their associated epiphytic orchids and bromeliads, and understory plants.
Japanese climbing fern Small-leaf climbing fern ©Barry A. Rice/The Nature Conservancy ©Mandy Tu/The Nature Conservancy
Of particular concern may be climbing fern impacts on native vegetation within many of the region's high-quality natural areas. A review by Pemberton and others [23] indicated that, as of 2004, small-leaf climbing fern was rapidly spreading in southern Florida, including in Everglades National Park. Volin and other [38] expressed concern that efforts to restore Everglades hydrology to approximate a "pre-drainage environment," while perhaps reducing establishment and spread of many important nonnative plant invaders, may "improve the ecological conditions for small-leaf climbing fern." Lott and others [16] reported that small-leaf climbing fern "has been observed overtopping tree canopies among tree islands in the Arthur R. Marshall Loxahatchee National Wildlife Refuge" [16]. Volin and others [38] recorded an average of 14 small-leaf climbing fern infestations (defined as contiguous growth that had climbed above the shrub layer on 1 or more trees) per km2 along transects in the Big Cypress National Preserve and Big Cypress Seminole Indian Reservation. The most heavily infested transect contained 58 infestations per km 2.
Climbing fern invasion may also impact rare and threatened taxa. Reviews by Ferriter [5] and Langeland [15] indicate that climbing fern invasion in Florida threatens the rare plant ray fern (Actinostachys pennula), as well as the endangered Georgia bully (Sideroxylon thornei), common dutchmanspipe (Aristolochia tomentosa), and branched tearthumb (Polygonum meisnerianum).
Control: Removing dead material following climbing fern control activities may be desirable to reduce fuels and to promote native plant recovery. On-site disposal of dead climbing fern material, such as by burning, can reduce spore dispersal (reviewed by [5]).
Ferriter [5] provides an extensive review of climbing fern management in Florida, available online through Florida Exotic Pest Plant Council.
Prevention: Frequent monitoring and immediate removal of newly established climbing fern populations may be the best strategy for mitigating their spread, especially since spore production can be prolific and spores may be dispersed over vast distances [5].
Integrated management: No information is available on this topic.
Physical/mechanical: Repeated pulling and/or cutting can control small climbing fern infestations (reviewed by [28]). Cutting kills fronds above the cut site, but fronds can regrow from below the cut site and after pulling (reviewed by [5]).
Fire: See the Fire Management Considerations section of this summary.
Biological: Pemberton [24] and Pemberton and others [23] reviewed the developmental status (as of 2004) of biological control of climbing ferns in North America. In February 2005, more than 100 individuals of Austromusotima camptonozale, an Australian moth and the first biological control agent approved for use against small-leaf climbing fern in the United States, were released at the Jonathon Dickinson State Park, southeastern Florida. Larvae of A. camptonozale feed on small-leaf climbing fern leaves [6].
Chemical: Several sources indicate herbicides may be an effective tool for controlling invasive climbing ferns. A review by Langeland [15] suggests the most common climbing fern control method, as of 2004, has been application of glyphosate and metsulfuron herbicides, either individually or in combination. When plants have grown into the canopy, stems may be cut and herbicide applied to the rooted portion of the plant [15]. Roberts [30] indicated foliar spraying of glyphosate can control small-leaf climbing fern, but few data and no analysis were provided. Descriptive results from several "demonstration trials" in southeastern Florida suggest that glyphosate, triclopyr, and 2,4-D can be used to at least top-kill small-leaf climbing fern, and that triclopyr ester (vs. triclopyr amine) may be "translocated" within the plant following application [36]. According to Randall [28], managers at Florida Caverns State Park have treated large Japanese climbing fern infestations by pulling the plants down from the trees and spraying their foliage with triclopyr. A review by Ferriter [5], citing unpublished data, indicated that glyphosate was effective for controlling Japanese climbing fern, although some follow-up spot treatments were necessary. Triclopyr treatments, while initially providing greatest observed Japanese climbing fern mortality, were ineffective in the long term due to extensive regrowth.
Other authors have indicated that herbicide use for climbing fern control may be problematic. A review by Stanturf and others [34] suggested that Japanese climbing fern "cannot be controlled by any available herbicide." Small-leaf climbing fern can apparently "regrow after spraying" with herbicides (reviewed by [41]), although further details describing the biology of this phenomenon are lacking. Pemberton and Ferriter [25] suggested that chemical control of small-leaf climbing fern (and presumably also Japanese climbing fern) will be difficult without damaging associated vegetation.
Cultural: No information is available on this topic.
As of this writing (2005) there is no published information describing the importance of climbing ferns to livestock and wildlife.
Palatability/nutritional value: No information is available on this topic.
Cover value: No information is available on this topic.
As of this writing (2005), there are few published accounts of specific North
American habitat types and plant communities where climbing ferns are common or
likely to be found.
A survey of Big Branch Marsh National Wildlife Refuge in southeastern Louisiana
found Japanese climbing fern "well established" in both American beech
(Fagus grandifolia)-southern magnolia (Magnolia grandiflora) woods
and "mixed woods" (successional forests dominated by loblolly pine
(Pinus taeda)) [31].
A review by Pemberton and Ferriter [25] indicates that small-leaf climbing fern is
common in bald cypress (Taxodium distichum) stands and also occurs in pine
(Pinus spp.) flatwoods, wet prairies, sawgrass (Cladium jamaicense)
marshes, mangrove (Rhizophora, Avicennia, and/or Laguncularia
spp.) communities, and Everglades tree islands. Volin and others [38] found that
presence of small-spike false nettle (Boehmeria cylindrica), royal fern
(Osmunda regalis), resurrection fern (Pleopeltis polypodioides ssp.
polypodioides), and toothed midsorus fern (Blechnum serrulatum) were
significant (p<0.05) indicators of small-leaf climbing fern occurrence in Big
Cypress National Preserve and Big Cypress Seminole Indian Reservation, southern
Florida.
Breeding system: Climbing ferns reproduce sexually by spores. They are capable of intragametophytic selfing. Small-leaf climbing fern can also reproduce via intergametophytic selfing and outcrossing [16,39]. Lott and others [16] suggested that small-leaf climbing fern's mixed mating system facilitates long distance dispersal, as well as local adaptation in established populations.
Spore production: Volin and others [38] studied small-leaf climbing fern spore production at 2 sites in southern Florida. Approximately 1% of pinnules were fertile. Fertile pinnules averaged 133 sori, with an average of 215 spores per sorus. Each fertile pinnule could potentially produce 28,600 spores or ~15,000 spores per cm2 of fertile leaf area [38].
Spore dispersal: Climbing fern spores are wind-dispersed, potentially over great distances, particularly during storms [5,15,25]. Pemberton (unpublished data, reported in [25]) recorded 724 small-leaf climbing fern spores/m3/hour in the air in southeastern Florida.
Spore longevity: Climbing fern spores are thick-walled, providing "long environmental viability" (reviewed by [5]).
Plant establishment/growth: In a laboratory experiment, climbing fern gametophytes were sexually mature within 5 weeks of germination, followed by sporophyte production through week 12. Rapid development/reproductive rates may be an advantage in many Florida habitats where seasonal environmental conditions such as hydroperiod can vary widely [16].
Asexual regeneration: Small-leaf climbing fern (and presumably Japanese climbing fern) can apparently regrow aboveground tissues that are damaged by herbicides, mechanical injury, fire [36], or that are killed to the ground by frost (reviewed by [41]), although details describing this biology are lacking.
Lygodium (climbing fern) is a genus of about 40 species of ferns, native to tropical regions across the world, with a few temperate species in eastern Asia and eastern North America. It is the sole genus in the family Lygodiaceae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I).[1] Alternatively, the genus may be placed as the only genus in the subfamily Lygodioideae of a more broadly defined family Schizaeaceae,[2] the family placement used in Plants of the World Online as of November 2019.[3]
Lygodium are unusual in that the rachis, or midrib, of the frond is thin, flexible, and long, the frond unrolling with indeterminate growth and the rachis twining around supports, so that each frond forms a distinct vine. The fronds may be from 3–12 m (9.8–39.4 ft) long, depending on the species.
Lygodium species, known as nito, are used as a source of fibers in the Philippines. The fibers are used as material for weaving, most notably of traditional salakot headgear.[4][5]
Some Lygodium species are now considered very problematic invasive weeds in the southeastern United States. Populations of Lygodium have increased more than 12-fold over the past decade, as noted by Florida's Institute of Food and Agricultural Sciences.[6]
Japanese climbing fern (Lygodium japonicum) was added to the Florida Noxious Weed List in 1999. It is also a major problem in pine plantations, causing contamination and harvesting problems for the pine straw industry. Old World climbing fern (Lygodium microphyllum) infests cypress swamps and other hydric sites, forming a monoculture. This massive infestation displaces all native flora and fauna, completely changing the ecosystem of the area.[7]
Plants in this genus have basal chromosome counts of n=28, 29, 30.
Lygodium (climbing fern) is a genus of about 40 species of ferns, native to tropical regions across the world, with a few temperate species in eastern Asia and eastern North America. It is the sole genus in the family Lygodiaceae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the genus may be placed as the only genus in the subfamily Lygodioideae of a more broadly defined family Schizaeaceae, the family placement used in Plants of the World Online as of November 2019.
