Salvinia molesta

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Giant salvinia
Salvinia molesta.jpg
The fern Salvinia molesta floating on a pond surface
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Division: Polypodiophyta
Class: Polypodiopsida
Order: Salviniales
Family: Salviniaceae
Genus: Salvinia
Species:
S. molesta
Binomial name
Salvinia molesta
D.Mitch.
Giant salvinia completely cover Lake Wilson in Hawaii Salvinia molesta covering lake.jpg
Giant salvinia completely cover Lake Wilson in Hawaii

Salvinia molesta, commonly known as giant salvinia, or as kariba weed after it infested a large portion of Lake Kariba between Zimbabwe and Zambia, is an aquatic fern, native to south-eastern Brazil. [1] It is a free-floating plant that does not attach to the soil, but instead remains buoyant on the surface of a body of water. The fronds are 0.5–4 cm long and broad, with a bristly surface caused by the hair-like strands that join at the end to form eggbeater shapes. [2] They are used to provide a waterproof covering. These fronds are produced in pairs also with a third modified root-like frond that hangs in the water. It has been accidentally introduced or escaped to countless lakes throughout the United States, including Caddo Lake in Texas, where the invasive species has done extensive damage, killing off other life.

Contents

In Europe, Salvinia molesta has been included since 2019 in the list of Invasive Alien Species of Union concern (the Union list). [3] This implies that this species cannot be imported, cultivated, transported, commercialized, planted, or intentionally released into the environment in the whole of the European Union. [4]

Description

Salvinia molesta is a complex of closely related floating ferns; they can be difficult to distinguish from each other. This water fern is often grown as an ornamental plant but has escaped and become a noxious pest in many regions worldwide. There are a few different growth forms for S. molesta. The primary growth form is an invading form with small flat leaves to the tertiary or mat form with large, crowded, folded leaves. Under the best conditions plants can form a two-foot-thick mat. These mats can put a halt to recreational activities on lakes and waterways. S. molesta has been used to extract nutrients and pollutants from the water. When this plant is dried out, it is used as satisfactory mulch. [5]

Favored environmental conditions

Salvinia molesta prefers to grow in slow-moving waters such as those found in lakes, ponds, billabongs (oxbows), streams, ditches, marshes, and rivers. It prefers nutrient-rich waters such as those found in eutrophic water or those polluted by waste water. It does not usually grow in brackish or salty waters, but has been reported in streams with a tidal flow in southeast Texas. It copes well with dewatering, and while it prefers to grow in moderate temperatures, it will tolerate low or very high temperatures. The United States Geological Service believes that it could grow in zones 7a, 8, 9, and 10 of the USDA Plant Hardiness Map. [2]

Effects of environmental conditions

Environmental conditions can have a strong effect on this plant. S. molesta can survive on a mud bank for a short period of time, but because of the dry conditions, it cannot live there permanently. It grows best at a pH of 6–7.7 and at a water temperature of 20–30 °C. Growth can be increased in high light intensities. S. molesta cannot grow in high salt concentrations; the increase in salt causes a decrease in chlorophyll. [6]

Methods of introduction

The plant originated in southeast Brazil and was exported as part of the pet industry to be used in aquaria and garden ponds. From there, it escaped or was deliberately released into the wild. It may also have been brought in with fresh, iced fish. Once in a waterway, it can be spread by infested boats, which not only spread it to new areas, but also break up the plant, allowing it to propagate. It also is spread by waterfowl. [2] S. molesta has been spread by contaminated aquatic plant stocks, boats, and other watercraft. The movement of water spreads S. molesta, and the sale and exchange of S. molesta materials increases chances of release to the environment. [5]

Potential use for cleaning water pollution

Research done in the Philippines suggested the effectiveness of S. molesta for the treatment of blackwater effluent for an eco-friendly sewage system that uses a constructed wetland to clean the water. The result of the study showed that it can remove 30.77% of total suspended solids, 74.70% dissolved oxygen and 48.95% fecal coliform from the water. [7]

Distribution

The Brazilian floating fern known as Salvinia molesta is now widely distributed in tropical and subtropical areas. This floating fern is known for its capability to take over large bodies of slow-moving fresh water. S. molesta has been naturalized in Texas [8] and Louisiana, but has now also been found and reported in Alabama, Mississippi, Florida, and Georgia. It can also be found where the lower Colorado River borders Arizona and California. "While S. molesta rapidly colonizes new states, current populations are too small to assess, but have been targeted for eradication". The naturalized regions of Texas have 14 drainage basins that contain infested water bodies; these are used as impoundments on tributaries that flow near federally protected wetlands. [9] In October 2020 Texas Parks and Wildlife detected S. molesta on Lone Star Lake while surveying fish populations. [8]

Reproduction

It reproduces by asexual reproduction only, but it is capable of growing extremely quickly, starting from small fragments and doubling in dry weight every 2.2–2.5 days. It grows from fragments that have broken off or dormant buds that have been detached from the main plant. Each node has five buds, so potential for great and rapid spread is high. It also produces spores, but they are genetically defective and do not produce viable offspring.

Effect

The rapid growth rate of Salvinia molesta has resulted in its classification as an invasive weed in some parts of the world such as Australia, United Kingdom, New Zealand, and parts of the United States. Surfaces of ponds, reservoirs, and lakes are covered by a floating mat 10–20 cm (in some rare cases up to 60 cm) thick. The plant's growth clogs waterways and blocks sunlight needed by other aquatic plants and especially algae to carry out photosynthesis, thereby deoxygenating the water. As it dies and decays, decomposers use up the oxygen in the water. It also prevents the natural exchange of gases between the air and the body of water the plant has invaded, causing the waterway to stagnate. This can kill any plants, insects, or fish trapped underneath its growth.

Its ability to grow and cover a vast area makes it a threat to biodiversity. Large infestations covering a wide area may also pose a problem to migratory birds, as they may not be able to recognise an infested waterway when flying overhead, so may not stop at it. S. molesta provides ideal conditions for the breeding of mosquitoes that carry disease. The growth habit of Salvinia is problematic to human activities including flood mitigation, conservation of endangered species and threatened environments, boating, and irrigation. [10]

Cancer research

Researchers at Stephen F. Austin State University in Nacogdoches, Texas discovered that extracts of giant salvinia have shown promising signs of inhibiting growth of human cancer cells without destroying nearby healthy ones. [11]

Salvinia effect

The salvinia effect describes the stabilization of an air layer upon a submerged hydrophobic (water repellent) surface by hydrophilic (water-loving) pins. This physicochemical phenomenon was discovered on the floating fern Salvinia molesta by the botanist Wilhelm Barthlott (Universität Bonn) while working on the lotus effect and was described in cooperation with the physicist Thomas Schimmel (Karlsruher Institut für Technologie), fluid mechanist Alfred Leder (Universität Rostock) and their colleagues in 2010.

Control

Biological control

A tiny weevil, Cyrtobagous salviniae , found in the native distribution of S. molesta, is being studied as a biocontrol. C. salvinae was first used as a biological control in Australia at Lake Moondarra, a recreational lake in Mount Isa, Queensland in 1980. By mid-1981, the weevil had reduced the population to a few small patches. It ate the leaves of the weed, but preferred the buds. Its larvae ate the roots, rhizomes, and the buds. As the plant died, it turned brown and sank to the bottom of the waterway and decomposed. This weevil was used with success in other parts of the world (13 tropical countries) such as the Sepik River in Papua, Sri Lanka, Lake Ossa in Cameroon as part of an AMMCO project [12] to restore African manatee; Wappa Dam in Queensland, and lagoons (e.g. Kakadu National Park) in the Northern Territory, Australia. [10] In Australia, the moth, Samea multiplicalis was also released in the hopes that it would reduce the size of the weed population. While this moth did become established in Australia and spread, it was not effective as a biological control. A third species, the grasshopper Paulinia acuminata , was considered, but not released in Australia. However, this grasshopper has been deliberately released for control of Salvinia molesta in parts of Africa, Sri Lanka and India, and accidentally in Puerto Rico. [13] The giant gourami has long been known to prefer S. molesta and feed on it voraciously. It has been successfully used to control S. molesta in reservoirs of Sri Lanka. [14]

Mechanical control

Plants are removed by machine or harvesting equipment and by hand; the latter is suitable only for small infestations. Harvesting equipment also can encounter difficulties, as it cannot remove all of the infestation, it cannot access shallow areas, and equipment can be inhibited by large masses of the plant. Once removed, the plant must be dried, burnt, or disposed of in a manner that ensures it will not re-enter the waterway. Other methods to control the aquatic weed are dredging and chaining.

Chemical control

Chemical control on S. molesta is difficult as it does have some resistance to herbicides. The chemical fluridon has been successfully used, but it requires prolonged contact and is not effective if it is suddenly diluted by rainwater or any other influx of water. Other chemicals, such as hexazinone and diquat and double-chelated copper are used together to kill S. molesta. [2]

Prevention

Bans on the spreading, selling, relocation, and transportation of S. molesta may help in the prevention of further spreading. [15]

In Caddo Lake, efforts to eradicate S. molesta have included the farming and introduction of salvinia weevils which eat the plant. They are used as a method of biological pest control which from anecdotal evidence show a positive yet slow success rate.

Mapping

Satellite images are used to identify S. molesta in reservoirs in Texas. [16]

Chemistry

The phenolic compounds 6'-O-(3,4-dihydroxy benzoyl)-beta-D-glucopyranosyl ester, 4-O-beta-d-glucopyranoside-3-hydroxy methyl benzoate, methyl benzoate, hypogallic acid, caffeic acid, paeoniflorin and pikuroside can be isolated from Salvinia molesta. [17]

Related Research Articles

<span class="mw-page-title-main">Caddo Lake</span> Lake bordering Texas and Louisiana

Caddo Lake is a 25,400-acre (10,300 ha) lake and bayou (wetland) on the border between Texas and Louisiana, in northern Harrison County and southern Marion County in Texas and western Caddo Parish in Louisiana. The lake is named after the Caddoans or Caddo, Native Americans who lived in the area until their expulsion by the United States in the 19th century. The US forced most of them to move west to Indian Territory.

<span class="mw-page-title-main">Water garden</span> Garden with water as a main feature

Water garden or aquatic garden, is a term sometimes used for gardens, or parts of gardens, where any type of water feature is a principal or dominant element. The primary focus is on plants, but they will sometimes also house waterfowl, or ornamental fish, in which case it may be called a fish pond. They vary enormously in size and style.

<i>Salvinia</i> Genus of aquatic plants

Salvinia, a genus in the family Salviniaceae, is a floating fern named in honor of Anton Maria Salvini, a 17th-century Italian scientist. Watermoss is a common name for Salvinia. The genus was published in 1754 by Jean-François Séguier, in his description of the plants found round Verona, Plantae Veronenses Twelve species are recognized, at least three of which are believed to be hybrids, in part because their sporangia are found to be empty.

<i>Elodea</i> Genus of aquatic plants

Elodea is a genus of 6 species of aquatic plants often called the waterweeds described as a genus in 1803. Classified in the frog's-bit family (Hydrocharitaceae), Elodea is native to the Americas and is also widely used as aquarium vegetation and laboratory demonstrations of cellular activities. It lives in fresh water. An older name for this genus is Anacharis, which serves as a common name in North America.

<i>Hydrilla</i> Species of plant

Hydrilla (waterthyme) is a genus of aquatic plant, usually treated as containing just one species, Hydrilla verticillata, though some botanists divide it into several species. It is native to the cool and warm waters of the Old World in Asia, Africa and Australia, with a sparse, scattered distribution; in Australia from Northern Territory, Queensland, and New South Wales.

The mottled water hyacinth weevil, Neochetina eichhorniae, is a beetle that has been introduced as a biological pest control herbivore agent to waterways and lakes in countries worldwide to control the spread of the invasive noxious weed species Eichhornia crassipes, the water hyacinth, an aquatic plant native to the Amazon basin.

<i>Myriophyllum spicatum</i> Species of flowering plant in the family Haloragaceae

Myriophyllum spicatum is a submerged aquatic plant which grows in still or slow-moving water. It is native to Europe, Asia, and North Africa, but has a wide geographic and climatic distribution among some 57 countries, extending from northern Canada to South Africa. It is considered to be a highly invasive species.

<i>Hydrocotyle ranunculoides</i> Species of plant

Hydrocotyle ranunculoides, known commonly as floating pennywort, or floating marshpennywort, is an aquatic plant in the family Apiaceae. It is native to North and South America.

<i>Pontederia crassipes</i> Aquatic plant native to the Amazon basin

Pontederia crassipes, commonly known as common water hyacinth, is an aquatic plant native to South America, naturalized throughout the world, and often invasive outside its native range. It is the sole species of the subgenus Oshunae within the genus Pontederia. Anecdotally, it is known as the "terror of Bengal" due to its invasive growth tendencies.

<i>Cabomba caroliniana</i> Species of aquatic plant

Cabomba caroliniana, commonly known as Carolina fanwort and various other names, is an aquatic perennial herbaceous plant native to North and South America. Having been a popular aquarium plant, it has been exported around the world, and has become an invasive species in Europe and Australia.

<i>Cyrtobagous salviniae</i> Species of beetle

Cyrtobagous salviniae is a species of weevil known as the salvinia weevil. It is used as an agent of biological pest control against the noxious aquatic plant giant salvinia.

<i>Azolla pinnata</i> Species of aquatic plant

Azolla pinnata is a species of fern known by several common names, including mosquitofern, feathered mosquitofern and water velvet. It is native to much of Africa, Asia and parts of Australia. It is an aquatic plant, it is found floating upon the surface of the water. It grows in quiet and slow-moving water bodies because swift currents and waves break up the plant. At maximum growth rate, it can double its biomass in 1.9 days, with most strains attaining such growth within a week under optimal conditions.

<i>Samea multiplicalis</i> Species of moth

Samea multiplicalis, the salvinia stem-borer moth, is an aquatic moth commonly found in freshwater habitats from the southern United States to Argentina, as well as in Australia where it was introduced in 1981. Salvinia stem-borer moths lay their eggs on water plants like Azolla caroliniana, Pistia stratiotes, and Salvinia rotundifolia. Larval feeding on host plants causes plant death, which makes S. multiplicalis a good candidate for biological control of weedy water plants like Salvinia molesta, an invasive water fern in Australia. However, high rates of parasitism in the moth compromise its ability to effectively control water weeds. S. multiplicalis larvae are a pale yellow to green color, and adults develop tan coloration with darker patterning. The lifespan, from egg to the end of adulthood is typically three to four weeks. The species was first described by Achille Guenée in 1854.

<i>Salvinia auriculata</i> Species of fern

Salvinia auriculata is a species of plant in the Salviniaceae known by the common names eared watermoss, African payal, and butterfly fern. It is native to the Americas from Mexico south to Argentina and Chile. It is cultivated as an ornamental plant and it has become naturalized in the wild in some places.

<i>Salvinia minima</i> Species of aquatic plant

Salvinia minima is a species of aquatic, floating fern that grows on the surface of still waterways. It is usually referred to as common salvinia or water spangles. Salvinia minima is native to South America, Mesoamerica, and the West Indies and was introduced to the United States in the 1920s–1930s. It is classified as an invasive species internationally and can be detrimental to native ecosystems. This species is similar to but should not be confused with giant salvinia, Salvinia molesta.

<span class="mw-page-title-main">Aquatic weed harvester</span>

An aquatic weed harvester, also known as a water mower, mowing boat and weed cutting boat, is an aquatic machine specifically designed for inland watercourse management to cut and harvest underwater weeds, reeds and other aquatic plant life. The action of removing aquatic plant life in such a manner has been referred to as "aquatic harvesting".

The Salvinia effect describes the permanent stabilization of an air layer upon a hierarchically structured surface submerged in water. Based on biological models, biomimetic Salvinia-surfaces are used as drag reducing coatings (up to 30% reduction were previously measured on the first prototypes. When applied to a ship hull, the coating would allow the boat to float on an air-layer, reducing energy consumption and emissions. Such surfaces require an extremely water repellent super-hydrophobic surface and an elastic hairy structure in the millimeter range to entrap air while submerged. The Salvinia effect was discovered by the biologist and botanist Wilhelm Barthlott and his colleagues and has been investigated on several plants and animals since 2002. Publications and patents were published between 2006 and 2016. The best biological models are the floating ferns with highly sophisticated hierarchically structured hairy surfaces, and the back swimmers with a complex double structure of hairs and microvilli. Three of the ten known Salvinia species show a paradoxical chemical heterogeneity: hydrophilic hair tips, in addition to the super-hydrophobic plant surface, further stabilizing the air layer.

<span class="mw-page-title-main">Giant gourami</span> Species of fish

The giant gourami is a species of large gourami native to freshwater habitats in Southeast Asia. It has also been introduced elsewhere. The species is commercially important as a food fish and is also farmed. It can be found in the aquarium trade, as well. The species has been used for weed control on highly invasive aquatic plants like Salvinia molesta, as the giant gourami can be a voracious herbivore.

Aquatic plant management involves the science and methodologies used to control invasive and non-invasive aquatic plant species in waterways. Methods used include spraying herbicide, biological controls, mechanical removal as well as habitat modification. Preventing the introduction of invasive species is ideal.

References

  1. "TNC Global Invasive Species Team page". 9 October 2008. Archived from the original on 9 October 2008. Retrieved 26 March 2022.
  2. 1 2 3 4 "Archived copy" (PDF). Archived from the original (PDF) on 3 March 2016. Retrieved 16 July 2009.{{cite web}}: CS1 maint: archived copy as title (link)
  3. "List of Invasive Alien Species of Union concern – Environment – European Commission". Ec.europa.eu. Retrieved 27 July 2021.
  4. "REGULATION (EU) No 1143/2014 of the European parliament and of the council of 22 October 2014 on the prevention and management of the introduction and spread of invasive alien species". Eur-lex.europa.eu.
  5. 1 2 "Salvinia molesta". Q-bank.eu.
  6. Upadhyay, R. K.; Panda, S. K. (1 March 2005). "Salt tolerance of two aquatic macrophytes, Pistia stratiotes and Salvinia molesta". Biologia Plantarum. 49: 157–159. doi: 10.1007/s10535-005-7159-4 . S2CID   36123877.
  7. "Water fern (Salvinia molesta) shows potentials in removing water pollutants". Pchrd.dost.gov.ph.
  8. 1 2 "Giant Salvinia Detected on Lone Star Lake". Einnews.com. 30 October 2020. Retrieved 26 March 2022.
  9. "Status of Salvinia". Fl.biology.usgs.gov. 14 December 2012.
  10. 1 2 "Biological control of the aquatic weed, Salvinia molesta | CSIRO". Csiro.au.
  11. – SFA Public Affairs (11 July 2011). "SFA researchers discover cancer-treating potential of invasive plant | News from 2011 | SFASU". Sfasu.edu.
  12. Aristide, Takoukam. "Local Residents around Lake Ossa volunteer to help remove S. molesta by hand prior to weevil project". African Marine Mammal Conservation Organization. AMMCO. Retrieved 13 June 2020.
  13. Perez-Gelabert, D.E. (2002). "Paulinia acuminata (Orthoptera: Pauliniidae) introduced to Puerto Rico, West Indies", Cocuyo' 12: 5.
  14. "Vision Based Automated Biomass Estimation of Fronds of Salvinia molesta". Researchgate.net. 2 November 2018.
  15. "Salvinia complex". Cdfa.ca.gov. Archived from the original on 11 December 2012.
  16. Everitt, J. H.; Fletcher, R. S.; Elder, H. S.; Yang, C. (2008). "Mapping giant salvinia with satellite imagery and image analysis – Springer". Environmental Monitoring and Assessment. 139 (1–3): 35–40. doi:10.1007/s10661-007-9807-y. PMID   17516139. S2CID   39073590.
  17. Choudhary, M. I.; Naheed, N.; Abbaskhan, A.; Musharraf, S. G.; Siddiqui, H.; Atta-Ur-Rahman (2008). "Phenolic and other constituents of fresh water fern Salvinia molesta". Phytochemistry. 69 (4): 1018–1023. doi:10.1016/j.phytochem.2007.10.028. PMID   18177906.

Bibliography