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 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


New in February 2014 from the ISC

In February 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

Drosophila suzukii - The damage caused by D. suzukii larvae renders fruit unmarketable. In 2008 economic losses (based on maximum reported yield losses) for California, Oregon and Washington were estimated at 40% for blueberries, 50% for caneberries, 33% for cherries and 20% for strawberries. Production in these three states could sustain $511 million in damages annually because of D. suzukii. D. suzukii produces up to five times more hemocytes than D. melanogaster, making it significantly more resistant to wasp parasitism and making it less likely for indigenous specialized parasitoids to shift host onto it.

Drosophila suzukii ISC datasheet

Drosophila suzukii Invasive Species Compendium datasheet

Rattus rattus – R. rattus has directly caused or contributed to the extinction of many species of wildlife including birds, small mammals, reptiles, invertebrates and plants, especially on islands. The primary economic impact of R. rattus relates to agricultural and horticultural damage. It is capable of destroying up to 30% of crops annually. Phylogenetic restructuring of the ‘Rattus rattus complex’ (comprising the oceanic and Asian groups) is on-going. Based on molecular evidence, there are multiple species within what has historically been identified as Rattus rattus.

Leonurus japonicus – L. japonicus is a highly invasive weed widely naturalized in tropical and subtropical ecosystems. It commonly grows as a weed in waste places, disturbed sites and along roadsides and as an ornamental in gardens and yards. L. japonicus also invades pastures and arable land as well as coastal and dry forests. In a recent work, Xiong, et al. (2013) described the chemical composition and the antibacterial activity of essential oils from different parts of L. japonicus. These essential oils showed antibacterial activity against various Gram-positive bacteria.

Other invasive species datasheets recently published include…

Chamaecrista nictitans

Medicago polymorpha

Pantherophis guttatus

Amphisbaena fuliginosa

Datura ferox

Schilbe mystus

Protopterus aethiopicus

Horizon Scanning for Invasive Species

In this, the era of globalisation, increases in international trade, transport and travel have driven an upsurge in the diversity and volume of non-native species introductions to new areas worldwide. Introduced plant, animal and pathogen species may fail to establish in a new range, and where they do establish, may be environmentally benign. However, there is potential for introduced non-native species to become invasive, even after a (sometimes extensive) period of time without apparent negative impacts.

Preventing the introduction and establishment of a species considered to be an invasion risk is key to mitigating its potential impacts in a new area. For this to be done effectively, it is vitally important that countries conduct horizon scanning initiatives to determine the non-native species likely to arrive, to evaluate the threat posed should the organism become established, to determine by which pathway(s) the organism may be introduced and where appropriate, to convey to the competent authority the requirement for rapid response strategies to alert list species. The recent European Union (EU) draft regulation which aims to legislate for the control of invasive non-native species in the EU is likely to be focused on a list of priority non-native species. A significant number of the species on this list are likely to be alert species not yet present in the region, but which will be determined as threats through the horizon scanning and prioritisation process. The outcomes of this horizon scanning process are likely to be of great interest and importance to various concerned parties across the European continent and beyond, and will certainly be subject to close scrutiny.

Horizon -  Norma Desmond, Flickr

Are invasive species on the horizon?
Photo: Norma Desmond, Flickr

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