Statement 1 : Tackling IAS involves upfront costs and long-term benefits (avoided damage).

1. How to assess and compare short-term costs and long-term benefits of IAS-measures?
2. How to assess damage by IAS to biodiversity and ecosystem services and compare this with the cost of action?
3. Which unambiguous, uniform, quick and evidence-based scientific decision supporting systems are presently available to compare upfront costs with long-term benefits?
4. Which equivalent decision supporting systems are presently available for other environmental issues that can be used to compare upfront costs with long-term benefits?

Statement 2 : The considerable time lag between the introduction of an alien species and the onset of (damaging) invasive behaviour is hampering rapid response towards new alien species originally thought to be harmless.

1. How to assess the risk of future invasive behaviour?
2. Which unambiguous, uniform, quick and evidence-based scientific future risk assessment tools are presently available?
3. Which equivalent tools are presently available for other environmental issues that can be used here?

Statement 3 : Adaptation to climate change might require introducing alien species that are expected to be able to cope better with changing environmental conditions than the native species, despite the risk of those alien species becoming invasive.

1. How to fill the ecological niche when native European tree species move to the north and ecological barriers block natural migration of new species from the south?.
2. How to assess the risk of future invasive behaviour?
3. Which unambiguous, uniform, quick and evidence-based scientific tools to assess future risks are presently available?
4. Which equivalent tools are presently available for other environmental issues that can be used here?

Statement 4 : A population of a species introduced into the territory of another genetically different population of the same species might become invasive and outcompete that genetically different but original population.

1. What examples have already been demonstrated?
2. What is, according to present-day scientific information, the current magnitude of this problem?

Statement 5 : Some IAS have useful as well as harmful characteristics (e.g. Robinia) and a decision will be needed on whether to tolerate or to combat such IAS across the EU. (note: given the common internal market a uniform approach at EU level is required).

1. How to assess and compare useful and harmful characteristics of specific IAS at the EU-level?
2. Which unambiguous, uniform, quick and evidence-based scientific decision supporting systems are available?
3. Which equivalent decision-supporting systems are presently available for other environmental issues that can be used here?

Statement 6 : Citizen science is important to support IAS policy, for data collection on the distribution of IAS, as well as for data collection on public opinions on the measures to be taken.

1. How to internalise quality control within citizen science (e.g. initiatives such as Earth Science and EEA’s Citizen Science) and how to ascertain the quality of this quality control?
2. Which research outputs are available on the public opinion on policy measures to be taken to tackle IAS?