Native Ferns Research Articles

Restoring habitat for native and endemic plants through the introduction of a fungal pathogen to control the alien invasive tree Miconia calvescens in the island of Tahiti

Success of biological control programs is commonly assessed by studying the direct negative impacts of released agents on the target invasive species. Very few quantitative studies have focused on the indirect positive effects on native biodiversity. In this study, we monitored the response of the plant community (both native and alien species) in permanent plots located in four different sites in montane rainforests of the tropical island of Tahiti (South Pacific) severely invaded over decades by the alien invasive tree Miconia calvescens DC (Melastomataceae), after the release of a defoliating fungal pathogen Colletotrichum gloeosporioides f. sp. miconiae Killgore & L. Sugiyama. Results of five years of monitoring showed that total native and endemic species richness and plant cover increased in all sites and plots. Partial defoliation of miconia canopy trees (between 6% and 36%) led to significant recruitment of light-demanding pioneer species, but also to the appearance of some semi-shade and shade tolerant rare endemic species. Native ferns and angiosperms remained dominant (ca. 80%) in the forest understorey during the monitoring period. Colonization by a small number of alien plant species occurred in one permanent plot located at the lower elevation. We conclude that biological control may be considered a tool for partial habitat restoration and recovery of native and endemic species, but long-term monitoring is needed to confirm the stability and resilience of the “novel plant assemblage”.

Breeding biology of the Critically Endangered Galapagos Petrel Pterodroma phaeopygia on San Cristóbal Island: conservation and management implications

SummaryThe Galapagos Petrel Pterodroma phaeopygia is endemic to the Galapagos Archipelago, where it nests on only five islands. The species is considered ‘Critically Endangered’, mostly due to the effects of alien invasive species, which impair its reproductive success. During 2002–2003 we studied the breeding biology of the petrels nesting on San Cristóbal island. The study revealed particular characteristics of the San Cristóbal petrel population and differences compared to those of other islands, mostly related to nesting habitat, phenology, reproductive success and causes of mortality. On San Cristóbal, petrel nests were primarily located along ravines, in areas of dense vegetation cover formed by the endemic shrub Miconia robinsoniana and a wide variety of native ferns. Over 90% of the nests on the island were located on private agricultural land. The petrel population has a prolonged reproductive period covering 10 months. Laying dates occurred mostly from May to October, with a peak during August, although eggs may be occasionally laid between November and March. The incubation period averaged 50.8 days (range: 46–53), and parental care 103.7 days (range: 98–108). Overall reproductive success was 23.6%; 63.8% for eggs and 37.1% for chicks. Predation by rats was the primary cause (72.2%) of nest failure. Rat control campaigns and clearing of exotic plant species in areas of high density of petrel nests, as well as promoting cooperation agreements between conservation authorities and landowners of the properties where nests are located, are suggested among other critical management measures intended to reduce nest mortality and ensure the survival of the San Cristóbal petrel population.

Effects of Ungulate Management on Vegetation at Hakalau Forest National Wildlife Refuge, Hawai?i Island

We compiled and analysed data from 1987?2004 on vegetation monitoring during feral ungulate management at Hakalau Forest National Wildlife Refuge, a tropical montane rainforest on the island of Hawai?i. All areas in the study had previously been used by ungulates, but cattle (Bos taurus) were removed and feral pig (Sus scrofa) populations were reduced during the study period. We monitored six line-intercept transects, three in previously high ungulate use areas and three in previously low ungulate use areas. We measured nine cover categories with the line-intercept method: native ferns; native woody plants; bryophytes; lichens; alien grasses; alien herbs; litter; exposed soil; and coarse woody debris. Vegetation surveys were repeated four times over a 16-year period. Vegetation monitoring revealed a strong increase in native fern cover and slight decreases in cover of bryophytes and exposed soil. Mean cover of native plants was generally higher in locations that were formerly lightly grazed, while alien grass and herb cover was generally higher in areas that were heavily grazed, although these effects were not statistically significant. These responses may represent early seral processes in forest regeneration following the reduction of feral ungulate populations. In contrast to many other Hawaiian forests which have become invaded by alien grasses and herbs after ungulate removal, HFNWR has not experienced this effect.

Index Pteridophytorum Guadalupensium or a revised checklist to the ferns and club mosses of Guadeloupe (French West Indies)

Recent revision of the fern diversity of the French Caribbean island of Guadeloupe and its dependencies (Marie Galante, Les Saintes and La Desirade) resulted in the listing of 292 native ferns and club mosses in 28 families and 88 genera, of which eight ferns are endemic to Guadeloupe and 20 taxa are only recorded from the Lesser Antilles. Additionally, 21 species have recently been found to be naturalized. Nineteen new combinations are made and a new hybrid is described. Many types from the Fee collection have been reassessed and a number of names are lecto- or neotypified. Studied specimens are cited and localities are provided. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161, 213–277.

Fern Plant–Derived Protoapigenone Leads to DNA Damage, Apoptosis, and G2/M Arrest in Lung Cancer Cell Line H1299

Protoapigenone, isolated from the native fern plant Thelypteris torresiana, has anticancer activity against some cancer cells. However, the toxicological mechanism for protoapigenone is still unknown. Here, we investigated the anticancer effect of protoapigenone on human lung cancer cell lines. The comet assay showed that DNA damage induced by protoapigenone is dose-dependent. Trypan blue exclusion showed that the cell killing by protoapigenone is both time and dose dependent. The IC(50) of protoapigenone for 12, 24, and 48 h in H1299 cells is 6.11, 2.74, and 1.49 microM, respectively. Flow cytometry showed cell cycle perturbation such as sub-G(1) accumulation (at 1.57 microM for 48 h and at 3.57 microM for 12 and 24 h) and G(2)/M arrest (at 3.57 microM for 12 and 24 h) for protoapigenone. The sub-G(1) accumulation phenomena in the 3.57 microM for 24 h sample were shown to be apoptosis using Annexin V-immunofluorescence/propidium iodide staining. These results suggest protoapigenone is a potential chemotherapeutic agent for lung cancers.

Protoapigenone, a novel flavonoid, inhibits ovarian cancer cell growth in vitro and in vivo

Flavonoids are polyphenolic compounds and capable of inhibiting the growth of human cancer cells. Protoapigenone, a novel flavonoid, was isolated from the whole plant Thelypteris torresiana (Gaud), a native fern in Taiwan. In the present study, we explored the cytotoxic effects of protoapigenone on ovarian cancer cells and the immortalized ovarian epithelial cells by XTT assay. The effects of protoapigenone on cell cycle progression and apoptosis were also analyzed by FACS analysis, immunofluorescence study and immunoblotting analysis. The anti-ovarian cancer effect of protoapigenone was further examined using nude mice xenograft assay and immunohistochemistry. Our results showed that protoapigenone had a significant cytotoxicity on human ovarian cancer cells MDAH-2774 and SKOV3 but not on the immortalized non-cancer ovarian epithelial cells HOSE 6-3 and HOSE 11-12. Protoapigenone arrested MDAH-2774 and SKOV3 cells at S and G2/M phases via decreasing the expression of p-Cdk2, Cdk2, p-Cyclin B1 and Cyclin B1, as well as increasing the expression of inactive p-Cdc25C. Besides, protoapigenone had an enhanced cytotoxicity on SKOV3 cells enriched at S and G2/M phases, and ability to induce apoptosis through decreasing the protein levels of Bcl-xL and Bcl-2 and increasing the cleaved PARP by activating caspase-3. In nude mice study, protoapigenone treatment significantly suppressed the tumor growth, without major side effects. Taken together, protoapigenone showed a significant anti-ovarian cancer activity with low toxicity, suggesting its potential to be developed as a chemotherapeutic agent.

Molecular biogeography and origins of the Hawaiian fern flora

Abstract Located approximately 4000 km from the nearest continent, the Hawaiian Islands comprise the most isolated archipelago on Earth. This isolation has resulted in a unique flora that includes nearly 200 native ferns and lycophytes, 77% of which are endemic to the islands. Because the Hawaiian Islands are volcanic in origin, all abiotically dispersed organisms must have arrived there via the wind or the water. Fern spores are most likely dispersed through the air, and thus patterns of air movement have undoubtedly played a significant role in determining the geographic origins of the ancestors of the Hawaiian ferns. We have identified four possible climate-based or weather-based spore dispersal hypotheses that could have resulted in the movement of ancestral spores to the Hawaiian Islands: (1) the northern subtropical jetstream, moving spores from Indo-Pacific regions; (2) the trade winds, dispersing spores from Central and North America; (3) storms carrying spores from southern Mexico and/or Central ...

Plant Colonization and Arsenic Uptake on High Arsenic Mine Wastes, New Zealand

Substrates associated with two historic gold mining sites in north Westland, New Zealand, have locally very high arsenic concentrations (commonly 10–40 wt% As). The substrates consist of iron oxyhydroxide precipitates, and processing mill residues. Waters associated with some of these substrates have high dissolved arsenic (commonly 10–50 mg/L As). Natural revegetation of these very high arsenic sites has occurred over the past 50 years, although some areas of substrate remain bare. Revegetating species include native and adventive shrubs, adventive grasses, rushes, and mosses, and native ferns. Revegetation by higher plants follows initial colonization by mosses, and some shrubs are growing directly in high-arsenic substrate. Shrubs, especially manuka (Leptospermum scoparium), gorse (Ulex europaeus), tree fuchsia (Fuchsia excorticata) and broadleaf (Griselinia littoralis) largely exclude arsenic from their shoots ( 0.2% dry weight). In particular, the moss Pohlia wahlenbergii acts as a hyperaccumulator, with up to 3% (dry weight) As. Antimony (Sb) contents of all plants are about one thousandth of that of arsenic, reflecting the As/Sb ratio of the substrates. Plant establishment in the high-As substrates may be locally limited by low nutrient status, rather than arsenic toxicity. The shrubs, grasses, and reeds identified in this study are arsenic tolerant and largely exclude arsenic from their shoots so that revegetation with these species, can help to isolate the high-arsenic substrates from the surface environment. These species could be used as phytostabilisation agents on high-arsenic sites that are remote from human habitation. In contrast, the mosses, despite their high arsenic tolerance, are a less desirable component of revegetation of high-arsenic substrates because they actively transfer arsenic from the substrate to the biosphere.

Pteris umbrosa R. Br. as an arsenic hyperaccumulator: accumulation, partitioning and comparison with the established As hyperaccumulator Pteris vittata

The capacity of the Australian native fern Pteris umbrosa to function as an arsenic (As) hyperaccumulator (shoot:soil As concentration >1) was examined by growing plants under glasshouse conditions in an inert medium supplemented with As. Arsenic preferentially accumulated in the fronds, a trait of a hyperaccumulator. The As concentration of fronds decreased with age, being particularly high in the croziers and low in the senesced fronds. Below ground, rhizomes accumulated more As than adventitious roots. Uptake from a range of solution concentrations followed Michaelis Menten kinetics up to a soil solution As concentration of 400mgl(-1). The K(m) for As uptake by roots suggested the operation of a low-affinity carrier. The predicted Nernst membrane potential indicated that uptake was against the electrochemical gradient of As. At 600mgl(-1), the rate of As uptake increased and phytotoxic effects were indicated by a significant decline in biomass. Arsenic uptake and translocation in P. umbrosa and Pteris vittata were similar at low exposure to As. At higher exposure, As uptake and translocation by P. vittata increased more than in P. umbrosa. The growth rate of both ferns was similar, whereas the biomass distribution was not, with P. vittata having a much larger root mass. This suggests that As uptake by P. umbrosa roots was very efficient and may be improved by stimulating root growth to enhance its potential.

Romancing the grindstone on Gunningbland Creek: a reflective essay

[article extract] The days are lengthening, crops are ripening, and the air is sweet with Spring as I write. For the first time in years of drought there are pools of muddy water in Gunningbland Creek, the ephemeral stream that meanders across our farm towards its river, the Lachlan, in south-eastern Australia; and a brood of grey teal ducklings is dabbling in the sparse rushes and nardoo, a native aquatic fern, now miraculously regenerating after the recent rain. I nearly trod on the teals as I walked along the creek the other day: three tiny brown beings trying to be invisible in the drying grass, and further along, their parents pretending to be clods of dirt or speckled rocks. I stopped and pretended to be a Casuarina tree, but the teals weren't fooled! One adult flew a few metres away to perform her innate defensive strategy 'look at me, I've got a broken wing, catch me if you can and stay away from my young' while the other took off upstream to gracefully disappear around a bend. I moved, and the hatchlings rose as one, dashed into the muddy water, paddled furiously and scrambled up the opposite bank to become invisible balls of fluff again, but in safer, more distant grass.

Rapid nutrient cycling in leaf litter from invasive plants in Hawai?i

Physiological traits that contribute to the establishment and spread of invasive plant species could also have impacts on ecosystem processes. The traits prevalent in many invasive plants, such as high specific leaf areas, rapid growth rates, and elevated leaf nutrient concentrations, improve litter quality and should increase rates of decomposition and nutrient cycling. To test for these ecosystem impacts, we measured initial leaf litter properties, decomposition rates, and nutrient dynamics in 11 understory plants from the Hawaiian islands in control and nitrogen + phosphorus fertilized plots. These included five common native species, four of which were ferns, and six aggressive invasive species, including five angiosperms and one fern. We found a 50-fold variation in leaf litter decay rates, with natives decaying at rates of 0.2-2.3 year(-1) and invaders at 1.4-9.3 year(-1). This difference was driven by very low decomposition rates in native fern litter. Fertilization significantly increased the decay rates of leaf litter from two native and two invasive species. Most invasive litter types lost nitrogen and phosphorus more rapidly and in larger quantities than comparable native litter types. All litter types except three native ferns lost nitrogen after 100 days of decomposition, and all litter types except the most recalcitrant native ferns lost >50% of initial phosphorus by the end of the experiment (204-735 days). If invasive understory plants displace native species, nutrient cycling rates could increase dramatically due to rapid decomposition and nutrient release from invasive litter. Such changes are likely to cause a positive feedback to invasion in Hawai'i because many invasive plants thrive on nutrient-rich soils.

Arsenic Uptake by Native Fern Species in Thailand: Effect of Chelating Agents on Hyperaccumulation of Arsenic by Pityrogramma calomelanos

Nineteen native fern species collected from an area in Thailand with high arsenic concentration in soil and in ground water as a result of tin mining was screened for elevated arsenic concentration in fronds. Two species of fern were found to contain elevated arsenic in their fronds in nature: Pityrogramma calomelanos (108–1156 µg g−1 dried weight) and Pteris vittata (79 µg g−1 dried weight). Under hydroponic culture Pityrogramma calomelanos (a silver back fern) accumulated arsenic in its shoot at rate of 4616 µg g−1 (dried weight). The accumulation of arsenic in Pityrogramma calomelanos shoot doubled with the addition of an EDTA (Ethelenediamine tetraacetic acid) chelating agent. The highest accumulation occurred 6 weeks after exposure to 10 mg L−1 arsenic as disodium hydrogen arsenate. The addition of another chelating agent, DMSA (Dimercaptosuccinic acid), resulted in a 5-fold decrease in arsenic concentration in the Pityrogramma calomelanos shoot compared to control after 6 weeks of exposure to arsenic. The contrasting effect of the EDTA and DMSA chelating agent was attributed to the strong binding of the thiol group to arsenic ion. This study indicated that Pityrogramma calomelanos uptake and translocate arsenic in the form of arsenate and arsenite rather than the As–DMSA complex. Using phytoextraction efficiency calculations, it was determined that Pityrogramma calomelanos gave the highest arsenic phytoextraction efficiency at 6 weeks after exposure to arsenic in the EDTA treatment, with an efficiency of 77.8 mg As based on whole plant biomass.

Predator‐mediated apparent competition between an introduced grass, Agrostis capillaris, and a native fern, Botrychium australe (Ophioglossaceae), in New Zealand

This study provides an example of how invasive plant species may indirectly affect native species through apparent competition by altering the local invertebrate community. The native New Zealand fern Botrychium australe (Ophioglossaceae) is thought to benefit from disturbances such as fire, because this species is generally found in disturbed habitats with low shade and increasing competition. However, in this study we show that a mapped population of B. australe experienced a marked decrease in survival and reproduction after an accidental fire in May 1995. Mortality was not due to the direct effects of fire; in the year following the fire, survival was normal and reproduction was higher than in previous years. However, after 1996 an introduced grass (Agrostis capillaris) spread across the area and B. australe survival in the second to fourth years after the fire (1996–1999, 59.63%) was significantly lower than survival before the fire, and plants did not produce spores at all during this 3‐yr period. B. australe survival was not lower in plots with dense A. capillaris growth. From 1997 onwards, B. australe plants suffered very extensive defoliation by a herbivore, and insecticide and molluscicide experiments in 1999 and 2000 showed that the introduced slug Deroceras reticulatum was responsible for the damage. The slug increased after the fire in association with the spread of Agrostis capillaris, probably because this plant created a suitable habitat for slugs.

Native Fern Propagation in Glacier National Park's Native Plant Nursery

Native Fern Propagation in Glacier National Park's Native Plant Nursery

Garden Writers Plan to Write About

Abstract The five categories of plants projected by members of the Garden Writers Association of America (GWAA) to have the greatest future demand were herbaceous perennials, native ferns and wildflowers, ornamental grasses, herbs, and ground covers. This survey noted that the two most important plant traits likely to affect future demand are multi-seasonal color/interest and pest resistance/tolerance. In preparation of gardening communications about plants, the most valued sources of information were personal growing experience, readily available information, and success stories from the local arboreta/botanical garden. The type of plant material information most valued by Garden Writers was regional suitability, landscape requirements, and flowering habit.

The ecology of the climbing fern Dicranopteris linearis on windward Mauna Loa, Hawaii

Summary Dicranopteris linearis (Gleicheniaceae), a native fern common throughout the Old World tropics and Polynesia, forms dense thickets > 3m deep over large areas of open‐canopy, oligotrophic, wet Hawaiian rainforests. Our objectives were to identify leaf‐ and whole plant‐level traits that are key to its success and to determine its community‐and ecosystem‐level consequences in primary successional sites. Along an elevational gradient from 90 to 1660m, mean maximum net assimilation rates of Dicranopteris ranged from 2.9 to 5.0 μmol m−2 s−1, compared with 3.6–9.5 μmol m−1 s−1 in the codominant tree Metrosideros polymorpha. Gas‐exchange characteristics did not explain Dicranopteris' success, nor its trends in production. However, indeterminate, clonal growth form, shallow rhizomes, marcescent leaves with low decomposability, and a mat‐forming capacity enabled Dicranopteris to colonize sites and to maintain dominance via high effective leaf area, despte its low biomass. Phosphorus use efficiency, which reached 24 kg g−1, was exceptionally high, allowing colonization of phosphorus‐poor sites. Dicranopteris contributed up to 74% of above‐ground net primary productivity in a site where it contained only 14% of live biomass. It accounted for up to 57% and 47% of total nitrogen and phosphorus uptake by plants, respectively, where it contained only 24% and 30% of plant nitrogen and phosphorus. Dicranopteris leaves are short‐lived and slow to decompose; thus, fixed carbon is transferred quickly to soil detrital pools where it contributes to aggrading soil organic matter pools and may exacerbate oligotrophic conditions, thereby strongly influencing soil genesis and ecosystem development. The fern therefore influences forest‐floor light regimes and directs later community development. An exclusion experiment demonstrated that Dicranopteris competed with Metrosideros, but lack of revegetation in 40% of the exclusion area after 39 months showed that Dicranopteris also colonized microenvironments unavailable to its endemic codominants. Dicranopteris may play an important role in resisting invasions of exotic species into Hawaiian rainforests.

Demography and conservation ofBotrychium australe, a peculiar, sparse mycorrhizal fern

Abstract Botrychium australe is a sparse native fern which is demographically unusual in having only a single leaf at any one time and in probably being strongly mycorrhizal. Individual plants of B. australe were mapped and followed at Cass, inland Canterbury, from 1987 to 1993. Plants were long-lived, with a mean half-life of 11.2 years. Some plants (21%) failed to produce any above-ground tissue in 1 or 2 years but later resumed normal growth. Up to 14% of plants were missing in this way in any one year. It is not known if this represents subterranean predation of fronds or quiescence while the fern is supported by mycorrhizae. Demographically, B. australe is more similar to some orchids than to other ferns. In any one year, only 9–20% of plants produced fertile spikes with sporangia. Fertile spike production was strongly correlated with higher light intensity; plants in deeper shade (<10% of full light) were very unlikely to be fertile. Plants in deeper shade also had larger sterile (green) fronds. The...

Vegetation and checklist of Inaccessible Island, central South Atlantic Ocean, with notes on Nightingale Island

The physiography and climate of Inaccessible and Nightingale Islands are briefly discussed. The vegetation and the major plant associations are described. Notes are given on the ecology and distribution of each taxon. Taxa newly recorded for Inaccessible Island include Agrostis goughensis, A.holgateana, A. wacei, Calamagrostis deschampsiiformis, Carex thouarsii var. recurvata, Conyza albida, Elaphoglossum campylolepium and Uncinia meridensis. One species, C. albida, is alien to the Tristan group. Two native ferns Asplenium platybasis var. subnudum and Blechnum australe were found on Nightingale Island for the first time, and the presence of introduced Malus domestica orchards was recorded. Two unidentified taxa were found that may represent new species: Elaphoglossum sp. at Inaccessible Island and Apium sp. at both Inaccessible and Nightingale Islands. The total number of vascular plant species recorded at Inaccessible and Nightingale Islands now stands at 98 and 43, respectively, of which 26 (28%) and seven (16%) are introduced species. Only Airiplex plebeja and two species of Cotula occur at Nightingale Island but are absent from Inaccessible Island.

The seasonal course of frost resistance in some New Zealand pteridophytes

Abstract The frost resistance of fronds or pinnae of three native ferns (Blechnum penna-marina, Phymatosorus diversifolius, Polystichum vestitum), one introduced fern (Dryopteris filix-mas), and one introduced club-moss (Selaginella kraussiana), grown at low altitude in Dunedin, was examined over a 13-month period. Vegetative material of all species except Dryopteris showed similar patterns with little annual fluctuation and a maximum frost resistance of between −5°C and −7°C attained towards the end of winter. Fertile fronds of Blechnum and cones of Selaginella showed less resistance than their vegetative parts. Dryopteris showed marked winter hardening (to -11°C that was significantly associated with low temperatures. In contrast the other species showed a gradual increase in resistance as the season progressed and the leaves matured (which was not obviously associated with any of the major fluctuations in temperature and daylength), although low resistance in fronds of Blechnum and pinnae of Polystichu...

Rare or threatened vascular plants of Lord Howe Island

Abstract The native and endemic vascular flora of Lord Howe Island (31°35′S 159°05′E) is assessed for rareness and threatened status using three axes—distribution, abundance and threat. Seven angiosperms are believed to have become extinct since 1853. Of the 118 native angiosperms 25 are rare, 3 endangered and 4 vulnerable. Of the 62 endemic angiosperms 9 are rare, 1 is vulnerable. Of the 26 native ferns 5 are rare, 1 is vulnerable. Of the 17 endemic ferns, 3 are rare, 2 are endangered and 1 is vulnerable. The rarest species, known from fewer than ten individuals, are recent invaders. Proposed reserves are sufficient to protect all species except three restricted to grazed swamps or estuaries.