Tag: invasive alien species

New improvements to how impacts of non-native species are assessed recommended

A farmer sets a pheromone trap to fight tomato leaf miner. Photo by CABI.

The Centre for Agriculture and Bioscience International (CABI) has led an international team of non-native species (NNS) specialists who have compiled a list of recommendations to improve the way in which the impact of a range of invasive pests – such as the tomato leaf miner Tuta absoluta – are assessed, potentially helping towards ensuring greater global food security.

Lead authors Dr Pablo González-Moreno and Dr Marc Kenis, Senior Researchers at CABI are two of 89 NNS experts from around the world who have collaborated on the paper, published in NeoBiota, that calls for ‘more robust and user-friendly’ impact assessment protocols to predict the impacts of new or likely invaders as well as to assess the actual impact of established species.

The manuscript is the outcome of an enormous collective effort using 11 different protocols to assess the potential impact of 57 NNS to Europe yielding a total of 2614 separate assessments. This unique dataset has allowed the authors to identify which are the main factors increasing the robustness of protocols and provide recommendations on how the robustness and applicability of protocols could be enhanced for assessing NNS impacts.

As reported in the study, entitled ‘Consistency of impact assessment protocols for Non-Native Species’, Dr González-Moreno and fellow scientists – from 80 institutions including the UK-based Centre for Ecology & Hydrology (CEH), University of Milan, University of Bern and Queens University Belfast – argue that ‘assessment of the realised or potential impacts of NNS is particularly important for the prioritization of management actions.’

Millions of the world’s most vulnerable people face problems with invasive weeds, insects and plant diseases, which are out of control and have a major impact on global prosperity, communities and the environment. Developing countries are disproportionately affected.

The global cost of the world’s 1.2 million invasive species is estimated at $1.4 trillion per year – close to 5 percent of global gross domestic product. In East Africa, five major invasive species alone cause $1 billion in economic losses to smallholder farmers each year.

The scientists believe that, currently, the large variety of metrics adopted to measure the impacts of invasive species undermines direct comparison of impacts across species, groups of taxa, localities or regions. They go on to argue that in general we have ‘little understanding of the patterns in consistency of impact scores across assessors and protocols, and more importantly, which factors contribute to high levels of consistency.’

Dr González-Moreno said,

“There is an increasing demand for robust and user-friendly impact assessment protocols to be used by professionals with different levels of expertise and knowledge.
Robust NNS impact protocols should ideally result in accurate and consistent impact scores for a species even if applied by different assessors, as long as they have the adequate expertise in the assessed species and context.
Several key factors should be taken into account when selecting or designing an NNS risk assessment protocol, such as the aim, the scope, the consistency and the accuracy of the outcomes, and the resources available to perform the assessment – for example time or information available.”

In compiling a list of recommendations for improved NNS impact protocols, Dr González-Moreno and the team of researchers used 11 different protocols to assess the potential impact of 57 species not native to Europe and belonging to a very large array of taxonomic groups (plants, animals, pathogens) from terrestrial to freshwater and marine environments.

They agree that using a ‘5-level scoring, maximum aggregation method and the moderation of expertise requirements’ offers a good compromise to reducing inconsistencies in research findings without losing discriminatory power or usability.

Dr González-Moreno added, “In general, we also advise protocol developers to perform sensibility tests of consistency before final release or adoption. This is crucial as if a protocol yields inconsistent outcomes when used by different assessors, then it is likely that decisions taken based on the results could be variable and disproportionate to the actual impacts.”

Original source:

González-Moreno P, Lazzaro L, Vilà M, Preda C, Adriaens T, Bacher S, Brundu G, Copp GH, Essl F, García-Berthou E, Katsanevakis S, Moen TL, Lucy FE, Nentwig W, Roy HE, Srėbalienė G, Talgø V, Vanderhoeven S, Andjelković A, Arbačiauskas K, Auger-Rozenberg M-A, Bae M-J, Bariche M, Boets P, Boieiro M, Borges PA, Canning-Clode J, Cardigos F, Chartosia N, Cottier-Cook EJ, Crocetta F, D’hondt B, Foggi B, Follak S, Gallardo B, Gammelmo Ø, Giakoumi S, Giuliani C, Guillaume F, Jelaska LS, Jeschke JM, Jover M, Juárez-Escario A, Kalogirou S, Kočić A, Kytinou E, Laverty C, Lozano V, Maceda-Veiga A, Marchante E, Marchante H, Martinou AF, Meyer S, Michin D, Montero-Castaño A, Morais MC, Morales-Rodriguez C, Muhthassim N, Nagy ZA, Ogris N, Onen H, Pergl J, Puntila R, Rabitsch W, Ramburn TT, Rego C, Reichenbach F, Romeralo C, Saul W-C, Schrader G, Sheehan R, Simonović P, Skolka M, Soares AO, Sundheim L, Tarkan AS, Tomov R, Tricarico E, Tsiamis K, Uludağ A, van Valkenburg J, Verreycken H, Vettraino AM, Vilar L, Wiig Ø, Witzell J, Zanetta A, Kenis M (2019) Consistency of impact assessment protocols for non-native species. NeoBiota 44: 1-25. https://doi.org/10.3897/neobiota.44.31650

Additional information:

The paper is based upon work from the COST Action TD1209: ALIEN Challenge. COST (European Cooperation in Science and Technology) is a pan-European intergovernmental framework. The mission of COST is to enable scientific and technological developments leading to new concepts and products and thereby contribute to strengthening Europe’s research and innovation capacities.

Dr Pablo González-Moreno was supported by the CABI Development Fund (with contributions from ACIAR (Australia) and DFID (UK) and by Darwin plus, DPLUS074 ‘Improving biosecurity in the SAUKOTs through Pest Risk Assessments’.

 

Text originally published by CABI.

Invasive alien plant control assessed for the Kruger National Park in South Africa

Along with urban and agricultural encroachment and pollution mitigation, managing invasive alien species is a key intervention needed to protect biodiversity. Unfortunately, on a global scale there are not enough funds to meet the requirements for effective conservation everywhere, which means that scarce funds need to be allocated where they can be used most efficiently.

In order to find out whether the historical measures undertaken at the Kruger National Park in South Africa have been effective and optimised, researchers led by Prof. Brian W. van Wilgen of Stellenbosch University assessed the invasive alien plant control operations in the protected area over several decades. Their findings and recommendations are published in the open access journal Neobiota.

While the first invasive alien plants in the national park, which stretches over two million hectares, were recorded back in 1937, it was not until the mid-1950s that attempts at controlling them began. By the end of the century, the invasive alien plant control program had expanded substantially.

Dense invasions of the West Indian Lantana (Lantana camara) along the Sabie River in the Kruger National Park have required intensive mechanical and chemical control to clear.
Dense invasions of the West Indian Lantana along the Sabie River in the Kruger National Park have required intensive mechanical and chemical control to clear.

However, the scientists found out that despite several invasive alien species having been effectively managed, the overall control effort was characterised by several shortcomings, including inadequate goal-setting and planning, the lack of a sound basis on which to apportion funds, and the absence of any monitoring of control effectiveness.

Furthermore, the researchers report that over one third (40%) of the funding has been spent on species of lower concern. Some of these funds have been allocated so that additional employment could be created onsite, or because of a lack of clear evidence about the impact of certain species.

As a result of their observations, the team concludes three major strategies when navigating invasive alien species control operations.

Firstly, a thorough assessment of the impact of individual species needs to be carried out prior to allocating substantial funds. On the other hand, in case of a new invasion, management needs to be undertaken immediately before any further spread of the population and the subsequent rise in control costs. Monitoring and assessments have to be performed regularly in order to identify any new threats that could potentially be in need of prioritisation over others.

Secondly, the scientists suggest that the criteria used to assign priorities to invasive alien species should be formally documented, so that management can focus on defensible priorities. They propose using a framework employing mechanisms of assessments used in the International Union for Conservation of Nature‘s Global Invasive Species Database.

The authors also point out that re-allocating current funds to species of greater concern is needed for species that cannot be managed via less expensive solutions such as biological control. Taking care of alien plant populations living outside of the park, but in close proximity, is also crucial for the prevention of re-invasions of already cleared areas.

Sunset Dam heavily infested with water lettuce (left). The population was effectively eliminated by a combination of biological and chemical control (right).
Sunset Dam heavily infested with water lettuce (left). The population was effectively eliminated by a combination of
biological and chemical control (right).

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Original source:

van Wilgen BW, Fill JM, Govender N, Foxcroft LC (2017) An assessment of the evolution, costs and effectiveness of alien plant control operations in Kruger National Park, South Africa. NeoBiota 35: 35-59. https://doi.org/10.3897/neobiota.35.12391