Evaluating the efficacy of a key conservation management tool for Southern Ocean benthos

The Southern Ocean is biologically rich with much of the diversity present found among the animals living on the sea floor. Biodiversity patterns, as identified through the collections of the age of exploration (e.g. Challenger and Discovery) found that species tended to have broad distributions across Antarctic and sub-Antarctic regions with substantial connectivity inferred between island shelf regions. This pattern was again reflected in a more recent study using presence data lodged in public databases such as GBIF and SCAR-MarBIN. Large population sizes of well-connected populations across a broad area such as the Southern Ocean suggest resilient species with little conservation concern.

Investigations using DNA sequence data over the past 20 years have found that many of the species described in the 19th and early 20th century are complexes of several biological species. Some examples, such as the iconic red sea star Odontaster validus and the crinoid Promachocrinus kerguelensis have been more recently redescribed as comprising 3 and 8 species respectively, substantially increasing the recognised diversity present. However, in most cases the newly identified biological species remain undescribed and therefore unrecognised. Furthermore, most unrecognised species tend to have very limited ranges with little evidence of connectivity between populations suggesting that what was once considered a resilient species may in fact be several vulnerable species requiring attention of conservation managers.

One of the tools available to conservation management is the IUCN Red List and the associated process of evaluating the threats and vulnerabilities of species. This approach has proved very effective not only in identifying species requiring conservation management, but substantial recognition outside of experts regarding the understanding of a species red list classification, from least concern through to critically endangered. However, having a species name is an essential first step to the process, and for the undescribed species of the Southern Ocean it is unlikely that most of them will be described within the lifetime of current specialists. The unrecognised species appear forever to be hidden by their lack of species name.

The question we ask is how would “red listing” the individual unrecognised species, compared to red listing the named species, change the current impression that the Southern Ocean has a widespread, well connected and resilient fauna? How will conservation management and governance of the Southern Ocean change with more granular species distribution lists?

Research Methods

This research project will require a substantial analysis of the relevant literature to capture the details of the biology, taxonomy, biogeography and conservation status of the target species. Cruicially a review of current conservation management strategies currently in use in across the Southern Ocean would be undertaken.

The candidate would be required to undertake the IUCN Red Listing course (this is available online, free of charge). Red listing requires detailed accumulation of all biological and distribution data on the target species, along with assessment of all likely threats.

Four assesments will be made:

   - A category shift score: A standardised scoring protocol will be developed and used during the assessments. E.g. Red List categories assigned scores of Least Concern =0 -> Extinct=6. A “shift” from one score to another between comparisons can then be metricised. (Wilcoxon signed-rank test on paired category scores – would report a median shift and its 95% CI

   - Hidden threat rate: Proportion of genetic units whose individual category is higher than the complex.

   - Management urgency delta: for each complex record whether the complex crosses a defined threshold (e.g. the Vulnerable category), and whether any of the component genetic groups cross it. What is the proportion of complexes flipping? Binomial test against a null of 0.5 (no direction of bias) would show whether there is evidence of taxonomy underestimating a threat.

   - Criterion shift: determine which of the red listing criteria causes a change in category designation.

A McNemar’s test on a 2x2 table of management relevant / not relevant under lumped/split would test whether the results are systematic rather than random.

Proposed research schedule

Collecting and analysis of literature (months 1-3)

IUCN Red List assessment course (months 1-2)

Assessing 2-3 (more if possible) recognised species complexes (months 3-6)

Assessing unrecognised species (months 6-9)

Writing results and thesis (months 9-12)

Director of Studies: Dr Bernadette Snow (SAMS)

Supervisory Team: Dr Chester Sands (British Antarctic Survey)

Application Deadline: 1 June 2026

Interview date: 5 June 2026

Course Start date: 1 October 2026

Course duration: 12 months (full time)

(the student may apply for a further 12-month extension, subject to additional fees) 

Location: Based at The Scottish Association for Marine Science