In the eye of the invasive species storm

17th September 2014-  Last weekend I experienced first-hand the impacts that invasive species can have. While carrying out research on an infestation of Opuntia Stricta in Laikipia, I felt something lodge itself in my eye. The following day I visited a specialist, as efforts to wash the thorn out of my eye had been unsuccessful.

They found that one of the very fine thorns, which are found on the fruit of the cactus, had become trapped in my eyelid and was scraping along the cornea. According to the specialist, another two days with the thorn in my eye would have resulted in me developing a corneal ulcer; which could have cost me my sight in that eye.

The thorns of Opuntia Stricta fruit are incredibly fine. So fine that the specialist was only able to detect it using microscopy equipment and dye. As well as being an unpleasant experience, this incident highlights the serious implications for those who live in areas which are infested with Opuntia Stricta, where many people would be unable to afford to seek medical help should they experience the same thing.

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Opuntia Stricta can also have a significant negative impact on livestock. If they get thorns in their eyes, there is no way for the owner to remove them. This could potentially result in loss of sight. Equally, it is not uncommon for goats to feed on the Opuntia fruit where the same thorns damage the goat’s stomach. This has been linked to the death of many animals in areas where this weed is prevalent as well as overgrazing in uninfected areas which is putting strain on pastoral land in these areas (Dodd, 1940).

While invasive species are often perceived as a biodiversity threat, they have a very real impact on the livelihoods and health of those who live in the areas in which they infest.

 

 

New in August 2014 from the ISC

In August 2014 the following datasheets were published on CABI’s Invasive Species Compendium (ISC). You can explore the open-access ISC here: www.cabi.org/isc

Lepus europaeus (European hare) – the European hare has been widely introduced by humans from its original range in continental Europe and has successfully established populations in South Sweden, North and South America, Australia, New Zealand, Ireland and several Mediterranean and tropical islands. In its introduced range it can cause significant agricultural damage and compete or hybridise with native fauna. Conversely, populations have declined across much of its native range.

Lepus europaeus Invasive Species Compendium datasheet

Lepus europaeus Invasive Species Compendium datasheet

Myxobolus cerebralis (whirling disease agent) – this member of the parasitic myxozoan group causes whirling disease of salmon and trout, which causes fish to swim erratically, making feeding and avoiding predators difficult. M. cerebralis was first reported in Germany in the late 1890s, but, acting in cahoots with its invertebrate host, the sludge worm Tubifex tubifex, it has since spread throughout Europe. The international fish trade has helped it reach Africa, Lebanon, New Zealand and North America, where it may pose a risk to native fish species.

Ardisia crenata (coral berry) – native to east and southeast Asia, this evergreen shrub has introduced around the world and is widely cultivated as an ornamental plant. It invades forest margins and understory, where it can reduce light levels by 70%, thereby shading out native plants.

 

Other invasive species datasheets recently published include:

Alysicarpus vaginalis (alyce clover)

Caesalpinia pulcherrima (peacock flower)

Cortaderia jubata (purple pampas grass)

Juncus planifolius (broadleaf rush)

Lolium perenne (perennial ryegrass)

Melilotus albus (honey clover)

Mentha pulegium (pennyroyal)

Nasturtium microphyllum (one-row watercress)

Persicaria punctata (dotted smartweed)

Workshop held on future of Invasive Species Compendium

Members of the Invasive Species Consortium from the US, Mexico, Caribbean and South Pacific met in Washington DC on 4 August and unanimously agreed to keep the Invasive Species Compendium (ISC) an open access resource for a further five years. The ISC has been resourced by a diverse international consortium of government departments, development aid organizations and private companies. Consortium members agreed that work on the ISC to date was of global importance and utility, and should continue.

Invasive Species Compendium website

The Invasive Species Compendium website

The ISC is a global encyclopaedic resource that combines science-based information to support decision-making in invasive species management. Invasive species, such as non-native weeds, animals and microorganisms, are one of the main causes of biodiversity and economic loss worldwide, impacting livelihoods and human health. Since its launch, use of the ISC has continued to grow, now with over 400,000 users in 234 different countries. Read more of this post

New in July 2014 from the ISC

In July 2014 the following datasheets were published on CABI’s Invasive Species Compendium (ISC). You can explore the open-access ISC here: www.cabi.org/isc

Senna multijuga (November shower) is a shrub or tree native to South America that has been introduced to tropical regions around the world. It is tolerant of a variety of soil types and its seeds are easily dispersed by wind and people. Despite its ability to naturalize quickly and its invasiveness in Hawaii, S. multijuga continues to be spread intentionally as an ornamental plant.

Senna multijuga Invasive Species Compendium datasheet

Senna multijuga Invasive Species Compendium datasheet

Abrus precatorius (rosary pea) is a high-climbing, twining or trailing woody vine from the Old World tropics. Although the plant has a wide variety of uses, from medicine, food and sweetener to jewellery, horticulture and even as a weighing unit, the seeds are so toxic that a single seed can kill a human. This vine is known to be invasive to Cuba and many parts of Asia-Pacific, and is naturalized in many tropical regions including Hawaii, parts of the Marquesas and Singapore.

Senna spectabilis (whitebark senna) – epithets range from ‘environmental weed’ to ‘garden thug’ for this resilient and fast-growing tree. Native to tropical America, S. spectabilis is considered invasive in Australia, Uganda, Tanzania, Hawaii, French Polynesia and Cuba. It can spread rapidly to create monocultures and place native flora at risk.

 

Other invasive species datasheets recently published include:

Senna surattensis (golden senna)

Senna bacillaris (whitebark senna)

New in May 2014 from the ISC

In May 2014 the following datasheets were published on CABI’s Invasive Species Compendium (ISC). You can explore the open-access ISC here: www.cabi.org/isc

Tithonia diversifolia (Mexican sunflower) has been introduced to tropical parts of Asia and Africa and some Pacific islands from its native Mexico, Central America and Cuba. The combined might of rapid vegetative reproduction, hundreds of thousands of seeds and a high tolerance of heat and drought all contribute to this herbaceous plant’s invasiveness. Dense stands prevent the growth of young native plants.

Tithonia diversifolia Invasive Species Compendium datasheet

Tithonia diversifolia Invasive Species Compendium datasheet

Native to the Mediterranean region, Carduus pycnocephalus (Italian thistle) has been introduced around the world, presumably accidentally. Dense infestations of the thistle in pastureland can smother smaller plants, reduce livestock access to grass and even injure animals. It may also contribute to wildfires in California.

The ornamental shrub Lagerstroemia indica (Indian crape myrtle) has become invasive in many tropical and subtropical parts of the world. Originally planted around along roads and around homes, it has since spread to waste ground, disturbed sites and open grasslands in a variety of habitats, from South Africa to the Virgin Islands.

 

Other invasive species datasheets recently published include:

Indigofera spicata (creeping indigo)

Elephantopus mollis (elephant’s foot)

Briza maxima (large quaking grass)

Indigofera tinctoria (true indigo)

Ipomoea ochracea (fence morning-glory)

 

New in June 2014 from the ISC

In June 2014 the following datasheets were published on CABI’s Invasive Species Compendium (ISC). You can explore the open-access ISC here: www.cabi.org/isc

Solanum seaforthianum (Brazilian nightshade) is a very aggressive woody vine able to invade natural forests, natural grasslands, forest margins, urban bushland, riverbanks, crops, pastures, roadsides, disturbed sites and waste areas. Once established, it is able to grow forming dense monocultures that smother native plant species.

Solanum seaforthianum Invasive Species Compendium datasheet

Solanum seaforthianum Invasive Species Compendium datasheet

Astatoreochromis alluaudi (Alluaud’s haplo) is a cichlid fish native to East African rift lakes, satellite lakes and river systems. Common in the aquarium trade, it was also widely introduced into novel river and lakes systems in East Africa for the biological control of molluscs, where it is now widespread.

Calonectria pseudonaviculata (Buxus blight) is a fungal plant pathogen. It was identified relatively recently in the UK as an introduced species causing a devastating shoot blight of boxwood (Buxus spp.) plants that are commonly used in gardens and landscaping. This pathogen has been reported from other European countries in recent years, and may have been transported in asymptomatic infected plants or propagating materials. It survives well in plant debris and probably also in soil.

 

Other invasive species datasheets recently published include:

Alpinia zerumbet (shell ginger)

Galinsoga quadriradiata (shaggy soldier)

Rhamphicarpa fistulosa (no common name)

Sanchezia speciosa (shrubby whitevein)

Senna septemtrionalis (smooth senna)

Thunbergia fragrans (whitelady)

Zingiber montanum (cassumunar ginger)

New in April 2014 from the ISC

In April 2014 the following datasheets were published on CABI’s Invasive Species Compendium (ISC). You can explore the open-access ISC here: www.cabi.org/isc

Thunbergia alata (black eyed Susan) – Australia, Brazil, Central America and many Pacific islands are all threatened by this aggressive herbaceous vine. Once introduced into a suitable climate, often as an ornamental, it quickly establishes and spreads both sexually and vegetatively. T. alata is capable of smothering native vegetation, killing host trees, out-competing understory plants and negatively affecting the germination and establishment of native plants.

Thunbergia alata Invasive Species Compendium datasheet

Thunbergia alata Invasive Species Compendium datasheet

Indigofera hirsuta (hairy indigo) – native to Africa, Asia and Australia, this herbaceous legume has been widely introduced as a crop and forage plant. Its ability to adapt to a wide range of soil types, spread quickly and regenerate – even in burnt-out ground – has led it become invasive in many Pacific islands. It is also considered a weed in China, Brazil and parts of the USA.

Urochloa mutica (para grass) – U. mutica has been widely introduced to tropical and subtropical regions as a fodder grass. This species’ aggressive growth, high productivity and allelopathic abilities have allowed it to become one of the worst weeds in the USA, Mexico, Central America and Australia.

Other invasive species datasheets recently published include:

Allamanda cathartica (yellow allamanda)

Emilia fosbergii (Florida tassel-flower)

Zingiber zerumbet (shampoo ginger)

Nelsonia canescens (blue pussyleaf)

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