Invasive Alien Species

How can we classify the costs and benefits associated with IAS management?

This stream is to discuss, and if possible classify, the different costs and benefits associated with IAS and their management.  I would start with the suggestion that there are four categories to consider.

• Costs associated with the ongoing presence of a species
• Benefits associated with the ongoing presence of a species
• Costs associated with the management of a species
• Benefits resulting from the management of a species

It would be useful to discuss the usefulness of this classification, possible alternatives, the sub-categories that sit within each and the currencies in which they are measured.  For example, the costs of management include the practical economic costs of implementing a programme, but also possible costs in animal welfare terms arising from the chosen method, costs associated with social acceptability, together with the indirect costs of management, for example the contamination of ground water with a pesticide, on other aspects of biodiversity or ecosystem function.

I agree with this classification, the cost of the presence of the IAS should then be subdivided into costs of productivity loss, biodiversity loss, extinction of species, loss of ecosystem services and aesthetic value of an ecosystem.

Thank you Beavan

I agree with the categories you suggest, which have a lot in common with those used in current exercises to classify invasive species impacts under the EICAT and SEICAT initiatives.

It would be interesting to hear views on whether and how these sources and their classifications might feed in to assessment of the benefits/effectiveness of management.

Best Wishes

Pete

Thanks for this message and some interesting thoughts.
It may also be worthwhile to look into the costs associated with risk management, compliance, and enforcement, as well as the effectiveness of such measures.
regards,
Pandey

Thank you Pandey

Its good to hear examples from the prevention side of invasive species management.  The costs, benefits and effectiveness associated with prevention and interception are quite different from those operating post-border; pre-border they are more focused on pathways rather than individual species. 

Do participants have examples of the application of different assessment methods to the process of detection and interception at the borders?

Best Wishes

Pete

I agree with the categories you suggest, I agree also with this classification but I prefer the cost of the presence of the IAS should then be subdivided into costs economic, social, ecological …ect. I suggest also to add the cost of preventing introduction IAS. 

In Egypt and Arab countries, we have many successful stories in management of some IAS and others fails but we have not undertaking or apply a cost-benefit approach because of the difficulty of valuing the monetary benefits to environmental assets for most activities.

I agree with the categories you suggest, I agree also with this classification but I prefer the cost of the presence of the IAS should then be subdivided into costs economic, social, ecological …ect. I suggest also to add the cost of preventing introduction IAS. 

In Egypt and Arab countries, we have many successful stories in management of some IAS and others fails but we have not undertaking or apply a cost-benefit approach because of the difficulty of valuing the monetary benefits to environmental assets for most activities.

Thanks Mohamed

I think your description of the problems of applying purely economic cost-benefit approaches to the management of invasive species reflects the experience of many countries, including our own experience in the UK. 

It would be interesting to hear what other related approaches might be more practical and useful to help assess and prioritise management.  There is clearly a need to have an evidence-based foundation for our management choices.  We have heard about approaches based more around cost-effectiveness and prioritisation, what are other countries doing to try and achieve this?

Best Wishes

Pete

This classification of costs and benefits makes sense.  Assuming that IAS includes species when they are utilised for food and agriculture should we make distinction within each classification between costs and benefits of the IAS in the wild and in the domestic production environment?

Thanks Graham
That's an interesting one, there are clear ongoing benefits associated with the presence of species when they are used for food and agriculture that should be included, but also costs should they become invasive.  I can see the value of describing the discrete benefits associated with a species use in agriculture, but less sure that a separate classification is needed for the associated costs of presence in the wild or in domestic production. What do you think? 
Pete

Hello all,

This is an interesting discussion and I echo the brilliant ideas already suggested. I am currently compiling a list of all exotic plants in Nigeria and so far, I have a database of about 1300 plants, of which about 200 of them are invasive. I hope to finish my endless analysis and publish my findings by the end of this year.

1. As already noted, some of these invasives also have economic uses (as food, medicine, etc.). In such cases, I think their cost of ongoing presence should be weighted against the benefits.

2. On a different topic, I also think management costs should also consider environmental impacts. For example, using heavy machinery to clear IAS also have severe impacts on the soil, erosion risks and habitat destruction, especially in aquatic habitats.

3. Another suggestion would be to categorize benefits and costs into different social groups: government, local communities, farmers? I have been thinking a lot about community-based invasive species management strategy, and I hope to write a literature and case study review on this soon.

4. I also think it is important to consider a few terminology clarifications: weeds vs. IAS. In many government institutions, they have Ministry of Agriculture that deals with what they call "weeds", while Ministry of Environment handles IAS. There is a lot of overlap, though a little difference exist, and I hope the final report from this discussion will capture recommendations that address both weeds and IAS.


Israel

My perspective comes from the aquaculture and fisheries sector for aquatic species.  In this case species can be introduced for aquaculture, or even for fisheries purposes.   There are obvious benefits from their use in aquaculture and these can be measured in a number of ways including net benefit, GDP of the sector etc.  However in the case of a species becoming invasive and a commercial fishery developing for that species there can be benefits of the species in the wild too (e.g. commercial fisheries for tilapia in Sri Lanka). Obviously is such cases there can be costs related to managing both the benefits and the negative impacts of the invasive species.

Message posted on behalf of Bella Galil who has had problems joining the forum

Dear Peter, colleagues,

In the introductory section mention should be made of the severe limits to management tools for marine IAS.

Vector management is the most effective strategy for preventing translocation, and thereby reducing introduction and spread of marine non-native biota. Lack of effective control on propagule transfer by the major vectors (shipping and boating, culture activities, trade, and canals), reduces management to frequently futile eradication and control efforts.
It has been advocated that a non-native species known or suspected to cause harm, and identified at an early stage in its establishment while spatially confined, should be removed, if an environmentally safe and effective method is used and eradication costs and environmental consequences are considered to be lower than the projected long-term impacts. Once the species has spread in the wild, eradication is impossible and even long-term reduction of the population to an economically or ecologically acceptable level  is rarely successful.
In 1999 the black-striped mussel, Mytilopsis sallei, was first recorded in marinas in Darwin, Australia. The area was quarantined, chloride or copper sulphatewere used to treat the waters, and the mussels were eradicated. But only a few removal programs have been successful, and all of these took place in confined environments – ports, marinas, lagoons and bays.
In most cases, eradication proved ineffective, even in confined environments. Eradication efforts  of Japanese carpet sea squirt in Shakespeare Bay, New Zealand, due to concerns for nearby shellfish farms,  lasted two years until they were no longer considered feasible. Cessation of control efforts resulted in rapid re-infestation. An eradication effort in Wales, U.K., where the same species was confined to a small marina, was initially successful, but the marina was rapidly recolonized and the species then spread throughout the U.K.
Attempts at controlling widespread IAS populations fare worse. Culling, labor-intensive and costly, has become the preferred strategy to reduce the density of the invasive lionfish in the western Atlantic and the eastern Mediterranean Sea. Culling may reduce lionfish in shallow reefs, but its effectiveness for long-term reduction of lionfish abundance is drastically undercut by high rates of recruitment from deeper-living populations.
Management of marine non-native species should pivot to PREVENTION through the cessation, reduction, or restriction of introduction pathways and vectors.
Bella Galil

These are all great suggestions for what to consider when conducting Cost-Benefit Analyses (CBAs) of both prevention and remediation of IAS. Some of the impacts are relativly easy to put an economic values to as it affect commercial activities / private goods (could be both positive and negative as pointed out in previos messages here), whereas other impacts affects non-market public goods in terms of ecosystem service impacts,, public health and cultural Heritage (both tangible and intangible). In Norway we have conducted Stated Preference studies (Contingent Valuation) for the Norwegian Environment Agency to put monetary values on the disutility people have from selected IAS (Freshwater Fish species, Iberian snail and Plants, which would be benefits in CBA of remediation measures.   
(assumming that the effectiveness of the measures is known, which can in many cases be difficult, both in the short and long term).
In Norway we have also conducted Cost-Effectiveness analysis of mitigation measures as often we lack benefit estimates(as was also pointed out in another posting here). in general in Norway,  Government guidelines for CBA (and CEA) from the Ministry of Finance as well as the ecosystem service approach and environmental valuation Methods and benefit transfer techniqaues are increasingly being used as an additional decision tool in environmental management.
Best regards Stale

Thanks Stale
Good to hear about the range of different methods you are applying in Norway.  Do you have examples or guidance on them that you could share with the forum?  How do you decide which method to apply in different circumstances?
Pete

In contrast the case of the Asian Green Mussel in Australia questioned whether the costs of eradication were justified given the likely impacts may have been small. See attached

Dear Bella,

I suggest you check about the control of Tubastraea species in the Brazilian coast. We have successful experiences in priority protected areas. Despite Tubastraea species are aggressive invaders the efforts are allowing local species to recolonize areas under control.
I agree with you that pathways in the marine environment must be better controlled. For example, Tubastraea is widespread in the Southeast Brazilian Coast, but it is not present in the two main areas for marine biodiversity conservation in Brazil (Abrolhos and Fernando de Noronha Archipelago). The main vector for Tubastraea are the oil platforms and so we have tried to impose some measures to reduce the risk of dispersion to free sites. However, the lack of international regulation on biofouling is preventing us to advance in this issue.

Best regards,
Tatiani

Posted on behalf of Bella Galil

Dear Tatiani (#1322)

I was greatly heartened that you have managed to control the invasive Tubastrea spp. in some MPAs.
I am familiar with the Sun-Coral Project but the publication by Creed et al. 2017 is focused more on the social aspects than on the long term results of the removal efforts and control of newly settled propagules.
Creed, J. C., Junqueira, A. D. O. R., Fleury, B. G., Mantelatto, M. C., & Oigman-Pszczol, S. S. (2017). The Sun-Coral Project: the first social-environmental initiative to manage the biological invasion of Tubastraea spp. in Brazil. Manag. Biol. Invasions, 8, 181-195.

As to the Abrolhos Bank, one of the areas of marine biodiversity conservation mentioned, Costa et al. 2014 claim Tubastrea has been established there.

Costa, T. J., Pinheiro, H. T., Teixeira, J. B., Mazzei, E. F., Bueno, L., Hora, M. S., ... & Rocha, L. A. (2014). Expansion of an invasive coral species over Abrolhos Bank, Southwestern Atlantic. Marine pollution bulletin, 85(1), 252-253.

I would be most grateful, as well as many colleagues, to learn of the costs and long tern effectiveness of the control projects

that keep Tubastrea at bay in Brazilian marine protected areas.

with best wishes,

Bella Galil

Dear Bella,

We have a few published studies on the effectiveness of the removal control of Tubastraea spp. (see below). There are other reports published in Portuguese and ongoing studies. Our staff from MPA also have reported that the control efforts are keeping ou reducing the population abundance.

Silva et al. 2014, Eleven years of range expansion of two invasive corals (Tubastraea coccinea and Tubastraea tagusensis) through the southwest Atlantic (Brazil)

De Paula AF, Fleury BG, Lages BG, Creed JC (2017) Experimental evaluation of the effects of management of invasive corals on native communities. Mar Ecol Prog Ser 572:141-154. https://doi.org/10.3354/meps12131
https://www.int-res.com/abstracts/meps/v572/p141-154

In regard to Abrolhos, Costa et al (2014) reported the presence of Tubastraea spp. in oil/gas platforms structures at the south end of the Abrolhos Bank. The formations of corals are free from the invaders, but the risk of dispersion is really concerning.

Kind regards,
Tatiani

Indonesia is a good case of this where invasive fish is their #1 IAS problem. There exotic fish are destroying native fisheries and some exotic species from aquaculture (e.g. Tilapia) are causing signficant environmental impacts. Still very hard to measure costs and benefits. The solution here is moving toward aquaculture based high productive male only lines.

Andy, I'm interested to learn more about the tilapia issues in Indonesia.  The case of tilapia is an interesting one as it has been introduced to over 100 countries, primarily for aquaculture, and is cultured commercially in many of these countries but there are relatively few documented cases of significant environmental impact so if you can point me to relevant reference material would be helpful, off line if necessary.

Graham. problem is I suspect that no-one with an IAS mindset has looked or that information hasn't been published. I learnt this during a trip to Indonesia where I was also told there is also evidence Tilapia are developing salt water tolerance so they become estuarine or even move via the coast into adjacent river systems. I'll ask Indonesian colleagues for refs. What is well documented as I am sure you are aware is Tilapia is pest fish #2 in Au after European Car

Dear Junko, Peter and all participants, thank you for making this virtual discussion possible.

Regarding the Graham post and others related to freshwater IAS, we identify the deleterious effects on the native species as the main concern.

In neotropic region, there´s almost nothing about this parameter. Since this region has the greatest species richness in the world, this is very important for us. But we don´t have enough information to subsidize a cost-benefit analysis.

See attached.

Dear Junko, Peter and all participants, thank you for making this virtual discussion possible.

Regarding the Graham post and others related to freshwater IAS, we identify the deleterious effects on the native species as the main concern.

In neotropic region, there´s almost nothing about this parameter. Since this region has the greatest species richness in the world, this is very important for us. But we don´t have enough information to subsidize a cost-benefit analysis.

See attached.

Dear Graham and Andy,

Tilapia (Oreochromis niloticus) is largely used in Brazil for aquaculture but it is also one of the worst invasive species. Assessing the impacts of tilapia invasion is not easy considering the freshwater habitats accumulate a range of impacts as damming, eutrophication and other invasive species. However, this species has been recorded affecting populations (pathogens, parasites, abundance, distribution), communities (diversity, composition, trophic web, extinction) and ecosystems (energy flows, biogeochemical cycles). Evidence of displacement or even competitive exclusion of native species, changes in the plankton community, and water quality are common, with implications for fisheries. The use of males for aquaculture purposes has been suggested although sexual reversion has been reported as well.

Graham, if you’d like I can send you some references on the impacts of tilapia as an invasive species.

Best regards,
Tatiani

In Australia this is what we call conflict species : beneficial for agriculture but harmful to the environment (e.g. high biomass grasses introduced for grazing but changing the ecology of our savannas). We have not really found a solution to dealing with this conflict unless one side is heavily weighted. The Ag benefits can be costed but not the environmental impacts. Buffel grass and Gamba grass are two where the environmental impacts are massive. They would both be in the top 10 environmental weeds, but they get blocked from being put on our Weeds of National Significance list for political reasons. This is where politics trumps risk assessment in prioritization so even if we could run a  classic BCA this wouldn't change things. Hopefully one day we will find a solution.

We agree with the classification of costs and benefits related to the management of IAS. It is suggested to include one more category, costs and benefits of prevention of exotic species, which represent a high risk of becoming invasive in a country.

Likewise, in Mexico a preliminary exercise was conducted for the years 2007 to 2012, to find out what would be the cost for the private sector that imports EEI, if the imports of certain exotic species were prohibited through regulation.

Also, the benefits of regulating imports of IAS were quantified; the avoided costs were quantified for damages and impacts and for control and eradication; To do this, the costs of control, eradication and economic damages were taken as reference, in which a number of countries have incurred as a consequence of the introduction of IAS of algae, plants, aquatic invertebrates, terrestrial invertebrates, fish and vertebrates.

Julio

Good day,

The classification of cost and benefit associated with IAS management just like in Australia SA refer them as conflict generating species which is based on the degree of benefits and their negative impacts. The negative impacts includes economic and socio economic impacts and benefits included economic and intrinsic benefit.
Therefore, most conflicts around the management of invasive species in South Africa are based on more than one value system hence the need to consider trade off in cases where the perceived benefits outweigh impacts.

I have attached a study that was done on the species listed as invasive species in SA.

Ntaka

Thanks Ntakadzeni
Interesting paper, particularly the classification based on relative costs and benefits of different species. Good contrast to the species-specific CBA approaches from SA previously posted.
Pete

ear colleagues we concur with the proposed classification and we would like to include two new "branches" 1) Costs associated with the future presence of a species and 2)  Benefits associated with the future presence of a species. These categories would aim at providing information regarding the shifts in species presence patterns thanks to climate change. Most countries have information regarding climate change impacts in their ecosystems and by adding economic information of such impacts it could render into key insights and leverage for decision making not only to IAS but for climate change policy. It is important to include IAS management not only in the context of trade but also in biophysical shifts due to human impact on global climate conditions.

Regarding the proposed classification we would like to add subclassifications:

Costs associated with the ongoing presence of a species
Health costs
Biodiversity loss costs (current and future)
Productive losses costs (i.e. losses in crop production)
Ecosystem losses costs (i.e. losses in tourims due to loss of ecosystems)
Benefits associated with the ongoing presence of a species
Costs associated with the management of a species
Scientific development costs (cost of research dedicated to understand, evaluate and assess IAS and their management)
Enforcement costs
Surveillance costs
Control and erradication costs
Insurance costs
Prevention costs (cost incurred to prevent or avoid IAS)
Benefits resulting from the management of a species

Another subclassification could be:

Direct costs: cost that can be easily allocated and represent financial cost for the environment, such as:
Species management cost (transport, captivity costs, inclusion cost, extinction cost)
Pesticides or other supplies
Deterioration of good or services provision (wood, water, air, landscape, crops)
Indirect costs: Costs that are difficult to calculate, such as:
Erosion
Eutrophication
Cultural damages (loss of emblematic landscapes)
Food chain shifts (diet modification due to IAS)

Best regards

Elaborating on the categorisation of costs and benefits, here is a more detailed framework for discussion.  This provides sub-categories together with the main currency in which each cost/benefit is typically measured. Some of these categories are clearly more important than others, but this is an attempt to cover all of the relevant categories.  I find it striking how many of these care measures in non-economic terms. The costs of presence are considered in current initiatives such as EICAT and SEICAT, and I've just posted information n the management costs of eradications, but it would be good to hear views on data sources to inform other categories.

Cost of presence
        Impact of species on human wellbeing                                                                       social
Impact of species on wider biodiversity                                                               biodiversity
Impact of species on the environment                                                                       environmental
Impact of species on economic activity                                                               economic
Benefit of presence
        Economic value of use of new species                                                                       economic
Addition of new species to local biodiversity                                                       biodiversity
Positive effects of new species on other species (including biological control)      environmental
Beneficial effect of new species on human wellbeing                                               social
Beneficial effect of new species on the environment                                               environmental
Improved global conservation status of the introduced species                              biodiversity
Cost of management
        Restriction in trade                                                                                                      economic
Costs of regulation                                                                                                      economic
Costs of interception/inspection                                                                              economic
Welfare impact of management (vertebrates)                                                      animal welfare
Costs of surveillance                                                                                              economic
Economic costs of removal                                                                                      economic
Costs of maintaining contingency capability                                                      economic
Social acceptability of management                                                                      social
Wider environmental impacts of management                                                      environmental
Benefit of management
        Reduced risk of future invasion and associated costs                                      multiple
Reduced current impacts                                                                                      multiple
Reduced future impacts                                                                                      multiple

Pete

Thank you for the interesting discussion!
Assessing the risks and benefits of an IAS is a problem that the people working to implement the EU regulation on IAS have been struggling with for the past several years. It is difficult enough to achieve an estimate of the costs that would be occurred by allowing an IAS to establish and spread, but to balance it against the potential benefits that the IAS could bring to society, increases the level of difficulty exponentially. Valuing biodiversity and ecosystem services is a developing science that is very complex.

Even if numbers and Concrete values for COSTs and benefits can be produced, in the end it will be a value judgement - not merely a comparison between numbers for cost and numbers for benefits. What benefits can outweigh the losses to biodiversity? We had such a discussion with a study on the costs/benefits of the indigenous crayfish (Astracus astracus) versus the introduced invasive crayfish species - where the results showed that the economic benefits for maintaining the invasive alien crayfish species outweighed the costs of the species.From the results we were advised to accept the invasve alien crayfish. This despite maintaining the IAS crayfish would lead to the extinction of the native species. This result was obtained because the intrinsic value of a native species was not considered. So we must be careful!

Best regards
Melanie Josefsson
Swedish Environmental Protection Agency

Hi Melanie

Nice to hear from you. As you say, with species that cause potential harm and are valued we are quickly into the realms of societal value judgements and out of the realms where level headed quantitative risk-benefit-cost assessments can really aid evidence based decision making beyond coin flipping advice. There is also the issue of the relevant jurisdictional environmental legislation. The decision you tried to make on crayfish would not have even been possible in either the US or AU for example, because the legislation does not allow for decisions that could drive a native species extinct or even to threatened and endangered status. No amount of risk-benefit-cost assessments helps there. Generally what happens is that the IAS can't be effectively controlled anyway (if biological control is not possible) so the only real course is "asset protection" securing core populations of the native species through protective barriers or trapping actions, the way we do with our feral cat proof fences in Australia. This becomes you cost-effective management action.

Cheers

Andy

Hi all,
I suggest to stay (use) the existing schemes like GISS (Nentwig - http://www.ibot.cas.cz/personal/pysek/pdf/Nentwig,%20Bacher,%20Pysek,Vila,%20Kumschick-Generic%20impact%20scoring%20system_EnvMonitAssess2016.pdf) or EICAT/SEICAT (Bacher...).
The advantage of using GISS is that it covers also socio-economic factors in one scheme and there is already bunch of datasets...
I think that GISS can be relatively easily transformed also to beneficiary site...
Reaveling graphs simmilar to those in paper Wilgen Richardson (Biol Invas 2014).
For many examples of costs we can go to EU RA or IUCN technical notes where many costs are specified...
All the best
Honza (Jan)

Since the goal of this forum is to develop AIS management tools and guidance I was wondering if we should not make a distinction between plants (AIP) animals (with various subsets) and fungi when we consider costs & benefits associated with AIS management.
Management tools and strategies differ significantly between the phyla targeted.
Also costs & benefits associated with AIS management should integrate the differences between the various regions of the globe: Controlling Ailanthus altissima in Europe is not similar to Prosopis control in Africa. I would recommend giving a special attention to regional livelihoods. The perception and the hierarchy of impacts related to AIS are different from a region to another. Impacts on biodiversity will tend to be the top concern in Europe or in N.America; this is less so in Africa or in Asia where AIS often pose a direct threat to food security and to livelihoods. Opuntia, Prosopis or Parthenimum have severe negative impacts on biodiversity, but for local communities they are first and foremost a disaster for cultures, crops, pasturelands and human health.