Protecting and restoring the Shiant Isles SPA through rat removal, and safeguarding other seabird island SPAs in the UK

PROJECT DESCRIPTION

BACKGROUND

The Shiant Isles Natura 2000 network site is a key site for seabirds. However, the site faced several threats, including the presence of invasive rats that predate important seabird colonies. When conditions were last assessed in 2008, both of the seabirds covered by the assessment razorbill (Alca torda) and common guillemot (Uria aalge) were classified as unfavourable declining. At present, few biosecurity plans exist for islands such as the Shiants, and no clear best practice guidelines were available. As a result, many key breeding colonies are vulnerable to invasions by alien species, and managers are ill prepared to respond to such invasions. Preparatory work for the LIFE project suggested that a sustainable eradication of rats was feasible at a reasonable cost on the Shiant Isles, particularly given their remote location.

OBJECTIVES

The main seabird species targeted by the LIFE Shiants project are razorbill (Alca torda), Atlantic puffin (Fratercula arctica) and European shag (Phalacrocorax aristotelis). In addition, the project expects to benefit a range of other species, including European storm petrel (Hydrobates pelagicus) and Manx shearwater (Puffinus puffinus).

The main objectives of the project are to:

Remove invasive rats from the Shiant Isles Natura 2000 network site, thereby eliminating a significant pressure on the existing seabird population;

Promote the colonisation of the Shiant Isles by European storm petrel and Manx shearwater, for example, through the use of call playback;

Protect the Shiants through improved biosecurity by establishing minimum biosecurity standards, producing a guideline document for island managers and carrying out training exercises across the country; and

Build expertise within the UK (and elsewhere in the EU) in island restoration, thereby reducing reliance on expensive external contractors.

Expected results:

Eradication of rats from the Shiant Isles Natura 2000 network site;

Increase of the populations of puffin, razorbill and European shag, with similar improvements in the status of other seabirds, including common guillemot, black-legged kittiwake (Rissa tridactyla) and northern fulmar (Fulmaris glacialis);

Increase of the populations of other species found on the Shiants, including terrestrial and wading birds, invertebrates and plants;

Increase in the rate of recovery of Shiant Isles Atlantic puffin, razorbill, European shag, and other seabird populations, as predicted by similar rat eradication projects elsewhere in the UK, with productivity at or above the level required to maintain stable populations by the end of the project (this level is 0.253 fledglings per pair a year for puffin, 0.500 for razorbill and 0.833 for shag);

The establishment of Manx shearwater and European storm petrel on the islands for the first time in at least 100 years (through active attraction measures as well as rat eradication), with anticipated prospecting for nests in the first year after eradication and egg laying in year three;

The development of a minimum standard for biosecurity for important seabird islands around the UK, and the delivery of a training programme linked to this standard; and

Raised public awareness of the threat invasive species pose to seabirds and biodiversity generally.

RESULTS

The LIFE Shiants project has met the main objective of removing invasive black rats from the Shiants and measures have been put in place to prevent rodents re-colonising the islands as set out in the After LIFE Plan. The project demonstrated the feasibility of carrying out ground-based rodent eradication operations on remote islands with difficult terrain, setting international best practice standards. For example, the team used a method of roped access on vertical cliffs and established concrete rat monitoring station (instead of plastic-based ones); lessons learnt will benefit future projects in Europe.

As a result of the rat eradication actions, the breeding success of seabirds such as puffin and razorbill has increased. For the puffin, productivity increased from 0.66 before eradication to a mean of 0.79 after (2016- 2018); for the razorbill, productivity increased from 0.72 before eradication to 0.79 after. The storm petrel was also confirmed to be breeding on the Shiants , demonstrating an increase in breeding sites for the species which should enhance resilience to climate change.

Storm petrels were attracted to the Shiants and bred successfully in 2018 for the first time on record. However, attempts to return the Manx shearwater were not successful during project period, though call playback is planned for five years after the project for both species. The project also produced an Island biosecurity manual, which was disseminated via four training workshops to provide necessary training to protect the UK’s most important seabird island SPAs. A review of biosecurity measures in place across UK seabird SPAs identified major gaps in biosecurity measures and led to the initiation of a follow-up UK-wide seabird island biosecurity LIFE project. The project was tackling biosecurity planning across 41 island SPAs in the UK. The biosecurity training also contributed towards enhancing capacity within the UK in island restoration. Moreover, those working on the project – six UK-based conservation staff and 15 volunteers involved in the rat eradication – have gained skills in working in island restoration and a large proportion have continued to work in that field.

Finally, the project has raised the profile of the Shiant Isles as an attractive place to view wildlife, in particular through the TV documentaries aired during the project. Removal of rats will avoid further damage to the island's archaeological features and therefore help to preserve the island's heritage. Boat operators that offer trips to the islands are benefiting from an increase in demand.

Further information on the project can be found in the project's layman report and After-LIFE Conservation Plan (see "Read more" section).