Threats to the Island

Despite Gough’s remoteness it has not escaped human exploitation and the negative impacts this so often brings. The main threats at the moment are invasive species, particularly House Mice and a small perennial herb, Sagina Procumbens.

Mice

In the 1800’s Gough sparked the interest of Sealers, who landed with the hope of making a living from the Subantarctic Fur Seals and Elephant Seals breeding here. This venture proved unsustainable and the Sealers did not linger long on the island. They have however, left a devastating legacy. They accidentally introduced House Mice, which have since thrived due to the abundant food supply and lack of predators. The population exploded, and up to 300 can now be found in a single hectare; higher densities than anywhere else in the world. They are also the largest of their species, thanks to a year-round supply of food. Unfortunately, over the last two decades it has become clear that this food supply includes the chicks of the Albatrosses and Petrels to whom the island is so important. Much research has since been carried out to uncover the extent of the problem, and the scientists involved have been horrified by their results. Up to a million seabird chicks are being killed every year, a rate which will lead to the collapse of seabird populations on Gough within the next few decades if we don’t intervene. Tristan Albatrosses, Great Shearwaters and Atlantic Petrels in particular are under threat. The method employed by the mice is excruciating to watch. Chicks are approached at night by up to ten mice at a time, who attack them from behind. Because mice have been on Gough for a relatively short amount of time (in evolutionary terms), the birds have not yet adapted to recognise them as a threat and so have no method of defending themselves. The attack continues over the course of several nights, with mice burrowing further and further into the chicks’ body cavity; literally eating them alive until the chick succumbs to its injuries. Even more heartbreakingly, often the mice will only eat part of the chick, leaving most of it to be scavenged by Southern Giant Petrels or Subantarctic Skua.

The video below shows the stark realities of this predation.

Warning: Contains graphic scenes which some viewers may find distressing.

Sagina

Gough is home to many introduced plant and invertebrate species. The most worrisome of these is a small perennial herb Sagina Procumbens, which was first discovered on the island in 1998. On the mainland this is a common and fairly harmless weed, but it has the potential to devastate the native invertebrate and plant-life of Gough. If left unchecked, it will spread across the island, forming dense mats which will outcompete the native flora.