MARTIN AUSTAD (BL MALTA): In the field with LIFE Artina – April 29 to May 5, 2019
Leaving the calm harbour of Pasadur the RIB skims lightly over the waves as we embark on a week of island hopping. Lastovo archipelago in SPA Lastovsko otočje comprises 46 islets so we had a busy schedule ahead. The aim of the team made up of LIFE Artina staff from Biom and BirdLife Malta, accompanied by RSPB* invasive mammal species expert Karen Varnham, was to survey the islets for presence of rats, the feasibility of rat eradication or control and check all occupied shearwater nests.
The islets are idyllic, with lush vegetation dominated by olive trees, holm oak or lentisk, surrounded by white rocks and clear blue sea. Nevertheless, here too human activity has affected native flora and fauna, mostly by introducing Black rats (Rattus rattus). The biggest concern for the LIFE Artina team is the high levels of nest predation by rats on seabird species such as the Yelkouan Shearwater (Puffinus yelkouan), Scopoli’s Shearwater (Calonectris diomedea) and Audouin’s Gull (Larus adudounii).
Rat presence was evident on most of the islets visited including the ones furthest from the main island, for example by the piles of hoarded olive seeds or pine cones, but even worse predated Yelkouan Shearwater eggs. Fortunately for the islands far enough from other land, once an intensive season of rat eradication is completed and followed by adequate biosecurity, the chances of rats returning is low. An important part of biosecurity is for instance to increase awareness amongst fishermen and other boat users to make sure they do not have rats on board their vessels and if they do, not to approach rat free islands. However, the size of islets also make a huge difference not only on the rat population they can support, but also on the effort needed to remove them. Despite being 10km from the nearest islet, the impressive island of Sušac surrounded by steep cliffs is too big (4km2) to rid rats from in a heartbeat. Instead it is focus of a feasibility study under LIFE Artina to lay the foundations for future full scale rat eradication.
On the other hand, for several of the islets at Lastovo distance to the main island is short enough for rats to swim over making re-incursion risk higher. On these LIFE Artina will follow a similar set up as carried out on Cominotto and St Paul’s Islands in Malta by LIFE Arċipelagu Garnija, where rats are controlled annually during the nesting season to make sure that seabird nests are safe. This has already paid off not only on the latter but also on Zaklopatica, Croatia’s largest Yelkouan Shearwater colony. It is also the best studied, so without the need for further baseline data the LIFE Artina team carried out rat control in February. On our visit peering through the cracks in the karstic landscape we could spot several Yelkouan Shearwaters incubating or brooding their newly hatched chicks. Our Croatian colleagues were overjoyed with the contrast to previous years, when nesting success could be close to zero % due to rats. Personally, even more striking than seeing Yelkouan Shearwaters land in trees and navigating dense bushes to reach their nest sites, was Zaklopatica’s proximity to a small fishing settlement well known as a nautical destination. Here locals and tourists can listen to Yelkouan Shearwater calls from their balconies! Such a close co-existence seemed only possible thanks to the well-designed lighting scheme along the promenade, light pollution virtually not reaching the seabird colony. Incidentally this is not only important to conserve the seabirds but to maintain Lastovo’s fame as a star gazer’s hotspot. While BirdLife Malta’s role in LIFE Artina is to transfer knowledge gained from previous seabird projects, Malta has clearly a lot to learn from the partnership as well, especially when it comes to tackling light pollution.
* RSPB – The Royal Society for the Protection of Birds