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)

The XIV International Symposium on the Biological Control of Weeds, Kruger National Park, South Africa, March 2014

In March 156 delegates from 24 countries travelled to the Kruger National Park in South Africa to attend the XIV International Symposium on Biological Control of Weeds (ISBCW) which was held at the Nombolo Mdhuli situated in the Skukuza Camp (2 – 7 March 2014). This quadrennial international symposium is a prestigious conference which provides delegates with an opportunity to present novel research on all aspects of biological weed control, to reflect on past experiences and discuss the way forward for the discipline and – this goes without saying – to catch up with old friendships and forge new ones. Three years on from the previous symposium in Hawaii and timed to commemorate “100 years of weed biological control in South Africa” 1, the African continent hosted the meeting for the second time in its history (the first time being the IX ISBCW held in Stellenbosch, South Africa in 1996). However, perhaps partly because of the increasingly severe constraints on funding and failure to gain official approval from respective governments/organizations, which made it impossible for many people to attend, this year’s symposium saw lower delegate numbers than previous ones. Some of the traditional “strongholds” in weed biocontrol, i.e. Australia, USA and Canada were clearly underrepresented, while the high number of European participants reflected the rapidly increasing interest in weed biocontrol in this part of the world. Sadly, apart from the participants from South Africa, only one other African country (Kenya) was represented. Last, but not least, it was an important and positive feature of attendance at this symposium that up-and-coming, younger scientists from all over the world were very well represented and the presence, prominence and enthusiasm of the next generation of weed biocontrol scientists at the XIV ISBCW seems to bode well for the future of the discipline.

Nombolo Mdhuli Conference Centre, Skukuza Rest Camp, Kruger National Park

Nombolo Mdhuli Conference Centre, Skukuza Rest Camp, Kruger National Park. Host venue for the XIV International Symposium on the Biological Control of Weeds (Photo: Marion Seier)

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New in March 2014 from the ISC

In March 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

Bothriochloa pertusa (pitted beard grass) - B. pertusa is a perennial grass native to eastern and southern Asia. It has been widely introduced in the Americas, Australia and the Pacific, either accidentally or probably in some cases deliberately for use as a forage grass. It has established itself in many native habitats where it is able to out-compete many native species due to its ability to establish dense mats and shade out slower establishing species.

Bothriochloa pertusa Invasive Species Compendium datasheet

Bothriochloa pertusa Invasive Species Compendium datasheet

 

Portunus segnis (blue swimming crab) – P. segnis is a marine nocturnal crab native to the western Indian Ocean. It is now considered established in the Mediterranean but invasive in the east and potentially invasive in the central and western Mediterranean. It is an active predator, tolerant to a wide range of temperatures and salinities and capable of reproducing throughout the year, with long-lived planktonic larval stages. Global warming is also expected to favour this tropical species.

Xanthium spinosum (bathurst burr) – X. spinosum is a highly invasive plant classified as one of the world’s worst weeds. It is now widely distributed throughout many regions of the world, where it is a common agricultural and pasture weed and a declared noxious species in many countries. Originating in South America, it has spread widely, probably via its spiked seeds which attach to animals and clothing or are a contaminant of hay or other products. It produces prolific amounts of seed that germinate easily. X. spinosum can quickly dominate large areas, outcompeting crops, forage plants and native flora. Control is possible but requires significant effort. There is considerable ongoing research into various methods including biological control.

 

Other invasive species datasheets recently published include:

Anredera cordifolia (Madeira vine)

Anthoxanthum odoratum (sweet vernal grass)

Opuntia monocantha (common prickly pear)

Green Invasion: Destroying Livelihoods in Africa [Video]

CABI, together with Tmax Productions, have produced a video called the ‘Green Invasion – Destroying Livelihoods in Africa.” The short film (approx. 7mins long) details how invasive weeds are impacting on the lives of rural communities in East Africa.

Although a large number of non-native species have become invasive in the region, this film focusses on four of the most problematic species namely Chromolaena odorata (Devil weed), Parthenium hysterophorus (famine weed), Prosopis juliflora (Mathenge) and Opuntia stricta (erect prickly pear). The excellent footage shows the extent of  weed infestations with accounts from community members on how these invasive plants are destroying the natural resource base on which they depend. It is clear that invasive weeds are destroying traditions, cultures and a way of life for millions of people on the continent.

However, all is not lost. The film notes that if effective management programmes are implemented, including biological control, we can make a difference to many people’s lives.

Although of general interest, the film is intended to raise the profile of invasive species and their impacts on livelihoods amongst donors and governments. We need them to take action and provide support for initiatives to manage one of the biggest threats to economic development on the planet.

Arne Witt
CABI Regional Coordinator, Invasives (Africa & Asia)
@WittArne


Weevil fight them on the waterbodies

Introduced to Britain in the 1980s through the aquatic trade Hydrocotyle ranunculoides, commonly known as floating pennywort, is rapidly spreading through Europe and particularly in the UK, Belgium, Germany, Italy, France and the Netherlands. Originating in Central and South America, this stoloniferous perennial plant is forming dense, impenetrable mats which rapidly dominate water bodies, outcompeting and displacing native species and compromising flood defences, navigation and leisure activities.  Despite its relatively recent introduction, establishment and spread have been exponential thanks largely to its extremely fast growth rate (up to 20cm per day) and its ability to re-generate from small fragments. In 2010, floating pennywort was added to section 14, schedule 9 of the UK’s Wildlife and Countryside Act 1981.  A recent report estimates its cost to Great Britain’s economy as £25.5 million each year through management, disposal, flooding and indirect costs to boating and angling.  News that from 2014 the sale of this plant will be banned is significant and welcomed.

Left - A sheep in a UK river clogged with Hydrocotyle (Credit: Trevor Renals); Right - Distribution map of floating pennywort invasion (Credit: DAISIE)

Left – A sheep in a UK river clogged with Hydrocotyle (Credit: Trevor Renals, Environment Agency)
Right – Distribution map of floating pennywort invasion (Credit: DAISIE)

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CABI welcomes EU action against invasive species

Water fern (Azolla filiculoides) covering a UK pond. Corin Pratt, CABI

Water fern (Azolla filiculoides) covering a UK pond. Corin Pratt, CABI

CABI welcomes action that the EU has recently taken (September 9, 2013) to protect member states against the adverse impacts of Invasive Alien Species (IAS).  The draft Regulation on the prevention and management of the introduction and spread of IAS will help to coordinate management and preventative measures across the whole of the EU, leading to what will effectively be a joint battle against IAS – a problem that costs the EU at least 12 billion Euros each year.

CABI’s initial views on four key areas are summarised below:

A list of invasive alien species of Union concern

Identifying invasive species of European concern is at the core of this Regulation and we are pleased to see that lists of these species will be compiled based on scientific evidence.  However, impact evidence, in the form of scientifically replicated studies, is currently lacking for many IAS across the EU. The lack of such data will inevitably have an impact on the strength of risk assessments for individual species.

Inclusion of chapter IV – Management of IAS that are widely spread

CABI is pleased to see that the draft Regulation highlights the valuable work that has been and continues to be conducted throughout EU member states, and welcomes the consultations to the draft Regulation, including all the steps needed to implement it. The inclusion of chapter IV – Management of IAS that are widely spread – is particularly welcomed, as these species are often overlooked due to the networks, resources and time needed to address them on an EU-wide scale.

Inclusion of all management methods, including biocontrol

CABI also welcomes the inclusion of all management methods into the Regulation (physical, chemical and biological actions), as the control and management of some of the more widespread EU weed species can only realistically be achieved using integrated pest management options, in particular classical biological control. Biological control also plays play an important role in protecting aquatic and riparian habitats, and so helps meet requirements of the EU Water Framework Directive as chemical and mechanical control options are often impractical or prohibitively expensive or taboo in such cases.

Inclusion of habitat restoration post control

It is encouraging  to see the inclusion of habitat restoration post control, though it will be difficult to implement from a practical point of view due to cost and the highly disturbed nature of many of the habitats invaded by IAS.

Dr Dick Shaw, CABI’s Global Director of Invasive Species Management says:

“It’s great to see this initiative come so far and that Member States may soon have to do something about invasive species that can and do wreak havoc to biodiversity and their environments.  There will be a lot of horse trading to come but I believe the will is there to make a change in the face of such a major and cross-cutting threat.”

Use them and lose

Is promoting the utilisation of invasive non-native species for commercial or other uses e.g. as a feed for livestock, use as a fuel or to produce biogas, a help or a hindrance to their control?

A view from Arne Witt, CABI Regional Coordinator, Invasives (Africa & Asia):

Promoting the utilization of any invasive non-native species (INNS) has largely contributed to their spread, especially in most developing countries which don’t have the capacity to develop and implement effective integrated management strategies.  Utilization as a control can only be effective if it forms part of an integrated management plan – on its own it merely exacerbates the problem.  There are many examples of where INNS have been intentionally spread by individuals because they have been led to believe that they can enrich themselves by growing and then utilizing an INNS – at low densities many INNS are beneficial, but it does not stay that way for very long – short-term benefits but long-term costs.

One needs to remember that utilization works from “inside out” whereas “control or management” works from “outside-in”.  In other words, the most cost-effective way to utilize an INNS is at the largest and densest infestations. As such you would build your biogas plant or sawmill in an area where the costs with regard to transport are lowest. In addition, you would not “eradicate” any of the plants you utilize – it is expensive and time-consuming to do so and why would you want to anyway, you want a renewable resource, so getting the plants to coppice, so that you can use them again in the future, is exactly what you want.  This is largely what is happening in Africa – those utilizing prosopis for charcoal do not apply herbicide to the cut stumps or dig out the rootstock – they want the plants to coppice. The same happens in India with regard to the utilization of lantana – communities don’t kill the lantana, they allow it to coppice. In addition, it does not make economic sense to utilize plants growing individually or in small pockets away from these dense infestations, especially in developing countries where we have poor infrastructure.  For a control/management strategy to be effective we need to work from the “outside-in”, removing individual plants or small isolated stands first before moving onto the dense stands – utilization works in the opposite way which is why it is ineffective as a management strategy on its own.

African landscape dominated by prosopis

African landscape dominated by prosopis (Arne Witt, CABI)

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Getting swamped: Australian swamp stonecrop (Crassula helmsii) in the UK

In January this year, large parts of southern Australia were ablaze with fierce bush fires, while most of the UK was covered in snow. Half a world away from each other, and at one point nearly 40ºC apart, there aren’t too many similarities to be drawn between the two locations. And yet, there is a water weed, Crassula helmsii, that survives happily in both extremes – and in the UK, where it has been introduced, this adaptability is proving extremely problematic.

 Crassula helmsii, also known as Australian swamp stonecrop or New Zealand pygmyweed, is a small semi-aquatic plant in the Crassulaceae family. As its common name implies, this low-growing succulent originates from the antipodes, but was introduced to Britain from Tasmania almost 100 years ago. Initially sold by garden and aquatic centres as an oxygenating plant, by the 1950s it had established in the wild, and from there it has spread to numerous ponds, lakes and waterways throughout the UK.

A mat of Crassula helmsii in flower

A mat of Crassula helmsii in flower

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Rhododendron ponticum – much more than just an invasive weed!

Rhododendron ponticum, native to southern Europe and south west Asia was introduced into the UK in the 18th Century. Since then, this plant has grown uncontrollably and is now a common sight throughout western parts of the British Isles in areas such as Cornwall, Wales and parts of Scotland and Ireland. Despite producing an attractive flower in the spring, Rhododendron can have damaging effects on the local environment. By growing rapidly this plant outcompetes native flora, decreases biodiversity and furthermore constitutes a sporulating host for the two devastating pathogens Phytophthora ramorum and Phytophthora kernoviae, meaning these pathogens not only infect but also reproduce on R. ponticum.

Rhododenron ponticum

A stand of invasive Rhododendron ponticum in Windsor Great Park (Picture copyright CABI).

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Rusty Solutions for a Prickly Problem

The state of Queensland has got an alien thorny invader: Prickly acacia, or in scientific terms Acacia nilotica subspecies nilotica.

Prickly acacia - Kunjithapatham Dhileepan

Prickly acacia invasion, north Queensland, Australia, Photo: Kunjithapatham Dhileepan, DEEDI, Australia

Prickly acacia is a shrub or small tree which belongs to the plant family Leguminosae, subfamily Mimosoideae, a family which also accommodates the sensitive plant Mimosa pudica, well-known as a curiosity house plant. The prickly invader A. nilotica is native to Africa, the Middle East and the Indian subcontinent and was introduced from India into Australia in the late 1890s. Originally imported as an ornamental, A. nilotica ssp. indica was later widely used as a shade and fodder tree for sheep. But what was initially a valued addition to the Australian flora soon became a menace. When the grazing regime in Australia changed from predominantly sheep to cows and the country also experienced a number of successive wet years, the balance swung in the favour of prickly acacia. The thorny shrub spread quickly and has now invaded around six million hectares of arid and semi-arid land in the State of Queensland. Acacia nilotica ssp. indica is also present in the Northern Territory as well as in Western Australia. Due to its substantial impact on the environment as well as on the economy, particularly on the livestock industry, prickly acacia was initially declared a noxious weed in Queensland in 1957. Subsequently the plant has also been listed as a “Weed of National Significance” for the whole of Australia. And Australians have every reason to be worried, as the prickly invader has got the potential to spread throughout the arid regions of the whole of northern Australia.

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