n the first three weeks of this forum we have heard from a wide range of contributors on use of costs and benefits to support decision making in a wide variety of forms.  Thank you all for your sharing your expertise.

As the final discussion point for this session, it would be useful to focus in on the specific use of economic cost-benefit analysis, where the various costs and benefits associated with the management of an invasive species can be all presented in common economic terms. It would be great to hear from contributors of examples of best-practice and existing guidelines in the use of economic cost-benefit analysis, its application, strengths and weaknesses.

From the examples presented in other threads, my own observation is that this specific form of analysis seems to have been most widely applied to assess the overall net benefit of individual species management programmes, and only rarely used to compare between different species or alternatives.  Is this impression correct, are there wider applications already in use in this area? Should we be making more use of this method to answer a wider range of questions?  Should an economic cost-benefit analysis feature as a recommended part of decision making for invasive alien species management?

It would be great to hear views and any final thoughts from contributors.

Hi Peter and all
I think economic cost benefit analysis is urgently needed in a country like Nepal which is among the most vulnerable countries (agriculture sector being 3rd most threatened out of 124 countries analyzed by Paini et al 2016) to invasive species. Natural ecosystems including protected areas and Ramsar sites and farmlands have been heavily invaded by invasive species. In every 1-2 years, new invasive species have been reported. Tuta absoluta (in tomato) was first reported in 2016 and Fall army worm (in maize) in 2018 in Nepal. Tuta is already widespread while fall army worm is in early stage of invasion. Similarly, there are clear evidences that Mikania micrantha and Chromolaena odorata are spreading from east to western part of Nepal with several satellite populations in the invasion fronts. Despite several commitments made by Nepal government in biodiversity strategy, there has been virtually no progress towards the management of these species. A national strategy for the management of invasive species was drafted nearly 3 years back but it is still awaiting approval from the government. One major reason for the lack of response to increasing invasions is probably that we do not know the economic cost of the invasion. If we can quantify the impacts in terms of $, policy makers and managers may prioritize the management of invasive species. Therefore, cost-benefit analysis should be a major part of recommendation of the decision making for invasive species, particularly in regions/nations where any kind of such data is unavailable.

From early in this forum I have been arguing for the increased use of cost effectiveness analysis as well as CBA both for specific and comparable situations. There are a number of advantages both operational and political. The operational ones relate to the lack of economic data available for environmental impacts. Sure CBA can be run much more cleanly for the agricultural pest situations Bharat and Adriana refer to but these are clearly more in the context of the FAO than the CBA. The political advantage is also quite compelling. A CBA will tell a politician how big the problem is. This is not a compelling political argument because politicians are faced with big costly problems everyday. What helps the politician is the understanding which of the many big problems faced he/she could actually make a difference against if it were tackled. Cost-effectivess analysis tells you not only what to do but the likely level of success and therefor return on investment that can be made. Politicians like to understand the solutions more than the scale of the problem.

I produced a summary of this forum at its half way stage, which can be found under the Guidance thread.  In this I suggested that the examples of evidence to support decision making using costs and benefits fell into four categories

• Demonstrating economic impact, often required to illustrate the importance of an issue or the need to manage.  Typically economic summaries of impact

• Showing a net economic benefit of management - often required to gain support for a management action. These include economic cost-benefit analyses, but also cost-effectiveness and a wider range of other methods to better incorporate non-economic values

• Optimising a management approach – determining the most cost-effective may to implement a programme – with examples provided in relation to surveillance or inspection. Primarily cost-effectiveness analyses.

• Prioritisation – choosing from a wide range of options (species, pathways, management alternatives) to best direct cost-effective management. Mainly risk analysis, but some use of economic cost-benefit and cost-effectiveness in some countries.

I think it is helpful to try and relate the evidence and analysis we chose to the decision we are trying to influence. I think Bharat's case from Nepal is an example of illustrating the importance of an issue and the need to manage. Listing the total economic impact of the threats has been undertaken in a range of studies worldwide and proved useful to raise the profile of the issue  - for example Pimentel's work which is widely cited.  

Pimentel, D., Zuniga, R. and Morrison, D., 2005. Update on the environmental and economic costs associated with alien-invasive species in the United States. Ecological economics, 52(3), pp.273-288.

However, studies of this type are not economic cost-benefit analysis as they do not include the assessment of the costs and benefits of management.  As Andy describes, other methods such as cost-effectiveness may also be used to help inform these decisions. 

Pete

How about make a cost-benefit/effectiveness analysis based on the Area, such as a park, an island, or a country?

Just like many experts talked in the past, prevent is very important to reduce the damage caused by the invasive species. Thus government should put the emphasis of invasive species management on the border biosecurity system.

Hello all,

This has been a great and enlightening conversation so far! My apologies for long silence and delayed engagement on these issues.
Nigeria, like most of West African countries, do not have WRA or national policy on invasive species management. Several efforts in the past have been focused on biological control or integrated management (chemical and mechanical controls, for example), funded or technically supported by European or United Nations institutions. Worse still, of the close to 100 federal government funded research institutions in Nigeria, none is dedicated to research on IAS prevention and management. Many of the current IAS were introduced deliberately or accidentally during colonial government system. Post-independence introduction were mostly by commercial/private botanical gardens and plant enthusiasts who brought in mostly ornamental plants.

In her most recent NBSAP to the CBD (December 2015), Nigeria intends to focus more on IAS prevention through border control, research and investigating the possibility of economic utilization of IAS, which has helped to reclaim lands from Prosopis juliflora in Ethiopia and India, among others. Currently, major focus of IAS management in Nigeria is on Typha spp. Grass, Nypha fruticans and Eichornia crassipes.

Very useful contribution from Andy on developing strategies for IAS management. As he mentioned, the first step is to know what IAS are there. Knowledge of IAS is very low in Nigeria, and ability to distinguish between native and exotic plants is poor even among agriculturalists and plant scientists. This is one of the reasons I am working on compiling a list of exotic plants in Nigeria. However, I have noticed that many countries in West Africa share common IAS. This provides two opportunities: (1) regional collaborations on IAS alert, so that once an IAS is detected in one country, others are alerted to look for it in their political boundaries or increase border control to prevent its entry; (2) regional collaborations on effective management strategy across landscapes and political boundaries. I think it may be useful to consider cross-boundary CBAs and IAS management, especially in developing countries.

To stress this further, I think prevention costs should consider public awareness and education, especially in developing countries, and the risks of IAS introductions.

As I think further about CBAs, I am curious as to how they are developed. With experience in valuation of ecosystem services, I think a way of evaluating costs and benefits of presence of IAS or impact on native species would be valuing the ecosystem services provided by the native species and perhaps by the IAS too. I am attaching two relevant papers on CBAs from Africa to enrich the literature on this conversation.

Finally, what’s in a name? I think clear definition of IAS and weed is needed, as I have seen both used interchangeably in this forum. Textbook definition of weeds limits their impact to agricultural landscapes, while impact of IAS is broader.

Israel

Hi Xubin

I included one paper on this as an attachment in an early post, but here are two others one as a link (http://eprints.qut.edu.au/75287/) and one attached

Best wishes

Andy