A couple of years ago I was fortunate to work on an IUCN Red List of Ecosystems project.

• Guru, S., Hanigan, I. C., Nguyen, H. A., Burns, E., Stein, J., Blanchard, W., … Clancy, T. (2016). Development of a cloud-based platform for reproducible science: A case study of an IUCN Red List of Ecosystems Assessment. Ecological Informatics, 36, 221–230. http://doi.org/10.1016/j.ecoinf.2016.08.003

This is based on a well thought through framework:

• The original exposition for IUCN ecosystem risk assessments was set out in Keith, D. A., Rodríguez, J. P., Rodríguez-Clark, K. M., Nicholson, E., Aapala, K., Alonso, A., … Zambrano-Martínez, S. (2013). Scientific Foundations for an IUCN Red List of Ecosystems. PLoS ONE, 8(5). http://doi.org/10.1371/journal.pone.0062111
• There is an associated guidelines for a Risk Assessment outlined in Rodriguez, J. P., Keith, D. a., Rodriguez-Clark, K. M., Murray, N. J., Nicholson, E., Regan, T. J., … Wit, P. (2015). A practical guide to the application of the IUCN Red List of Ecosystems criteria S2. Philosophical Transactions of the Royal Society B: Biological Sciences, 370(1662), 20140003–20140003. http://doi.org/10.1098/rstb.2014.0003

I have recently been reminded in several instances of the overlap with Health Impact Assessments, especially in complex eco-social contexts, and when stakes are high (so if one risk factor is critical the entire assessment gets that level of risk) and where data are not available (the use of the Data Deficient category).

It is worth thinking of when can’t achieve data quality or dose-response and/or base-line prevalence required for Burden of Disease methodological ‘purity’.

The options in addition to main criteria (Critically Endangered –> Vulnerable -> Least concern) are: Data Deficient, Not Evaluated and Near Threatened (scoring close to the threshold). Overall threat status is the highest level of risk on any of the 5 criteria. We ended up using DD a lot, but still get pretty good assessments.

A final note: the work I did led me to re-order the sequence of steps from the implied order of the Criteria A, B, C, D and E.

In practice it makes more sense to start at Criterion D ‘the Primary Biotic Variable’, because defining this at the outset means that there are many fewer potential variables to actually include (because ecosystems are big and complicated things with many possible biotic variables of interest). This gives the whole assessment a focus and targetted feel.

So in my work I did this sequence:

Criterion D The primary biotic variable

Do this first! This allows the scope of the assessment to be defined around a particular set of key biological and abiotic attributes of the ecosystem.

This requires an assessment for three time periods of the response of the principal biotic variable:

• D1 computes the disruption over the past 50 years
• D2 describes the projected disruption of the next 50 years
• D3 computes the disruption since 1750

Criterion E The probability of ecosystem collapse

Doing this second means that if there is any indication that this ecosystem is in peril then you can immediately classify it as “Critical” and not worry about doing any of the other steps. Just get on witht he job of saving it!

Criterion E is an overarching analysis of the impacts of biotic variables on the probability of ecosystem collapse within 50–100 years. We ran simulations to investigate the future resource

Criterion A Decline in ecosystem distribution

This is also done at three time periods:

• A1) Decline in distribution current (past 50 years)
• A2) Future decline (a) next 50 yrs or (b) any 50 year includes present and future
• A3) Historic decline (decline since 1750)

Don’t be afraid to use the “Data Deficient” category here!

Criterion B Restricted distribution

• B1 extent (convex hull around observed occurences) AND ANY a) decline, b) threat, OR c) small N “locations”
• B2 area of occupancy AND any a-c (assessed within 10km2 grid cells)
• B3 small N locations AND threats in short term (ie in the case of a mega landscape fire we have: burnt and unburnt = 2 locations)

NB “Locations” are those discrete areas of the ecosystem that would be affected by the most pervasive plausible threat (ie wildfire).

Criterion C Decline in abiotic processes

The most important abiotic variables are Temperature and precipitation and other climate-related variables were used for Criterion C

• C1 past 50
• C2 next 50 IPCC
• C3 since 1750