Rewild our islands, rewild our world

Rathbone Greenbank was delighted to support the 2018 Durrell Lecture, held on 15 November at the Royal Institution in London. 

This year’s lecture focused on the efforts of the Durrell Wildlife Conservation Trust to rewild island ecosystems, and featured presentations by conservationist, explorer and Durrell ambassador Monty Halls and Dr Nik Cole of the Round Island Restoration Programme in Mauritius.

Dr Lesley Dickie, the Trust’s CEO, began the evening by summarising the aim of its rewilding programme, its long-term targets and the importance of focusing on island ecosystems. Rewilding works to build healthy, resilient ecosystems to the point where they can function and thrive independently. The Trust is therefore seeking to meet several core objectives by 2025, the 100th anniversary of founder Gerald Durrell’s birth. These include the rewilding of 10 island ecosystems; major progress on the recovery of 100 threatened species; more effective operation of 500 conservation programmes; and the measurable connection of one million people to nature.

Island ecosystems are rich in extensive, often unique, biodiversity – but they’re also vulnerable to serious ecological harm. Though islands represent only 5% of the Earth’s landmass, they contain 37% of the world’s critically endangered species and have been the site of 61% of all recorded extinctions, many of which have a root cause in the introduction of non-indigenous species. Island rewilding is therefore an ideal global case study for determining how well damage to ecosystems can be reversed.

Monty Halls spoke passionately of his special attachment to the Galápagos Islands – “the birthplace of evolutionary science” – and summarised the time he spent on Santa Cruz with his young family, as recorded for the Channel 4 documentary, My Family and the Galápagos. While the series showcased conservation efforts in the region, it also served to demonstrate what is required of future generations to be effective custodians of the islands’ ecological wellbeing.

Designated a Unesco World Heritage Site in 1978, the Galápagos archipelago is the fourth-largest marine nature reserve in the world, covering 300,000 sq km. Contained within it are 440 species of fish, 40 of which are unique to the area. Indeed, the level of unique species is very high throughout the archipelago with around 95% of the species diversity of the Galápagos remaining from the first arrival of humans in 1535. Animals on the inhabited islands are nevertheless ‘environmentally naïve’ in terms of their proximity to humans so that islanders and visitors are required by law to keep their distance.

Increased tourism to the islands has exponentially increased the pressure on their ecological infrastructure. Travellers are walking ecosystems and the transfer of non-indigenous seeds and other foreign matter necessitates a robust approach to biosecurity; in 2015-16 alone, Ecuadorian authorities confiscated 14,180 restricted items from foreign visitors. Direct ecological impacts like illegal fishing are adding to those external pressures, and the islands haven’t been spared the consequences of seaborne plastic waste.

Despite these concerns, Monty found hope in the enthusiasm shown by ordinary islanders to protect the natural balance of their home. Whether engaging in small-scale, voluntary conservation efforts or assisting with the initiatives run by Durrell and the Galápagos Conservation Trust, people are making great lifestyle sacrifices to rewild their islands – positive steps that mirror Darwin’s assertion that “attitude is the difference between an ordeal and an adventure”.

Dr Nik Cole transported the audience to the Indian Ocean to summarise Durrell’s rewilding efforts on Round Island, a 2 sq km uninhabited islet north of Mauritius. Round Island is one of Durrell’s most important long-term restoration projects and the Trust has had a research presence there for over 40 years.

During the last 400 years, human intervention has devastated much of the region’s unique ecosystem. Only the more remote islands off Mauritius have been left relatively unscathed – Round Island itself escaped the worst devastation because it is one of the few islands in the world never to have been invaded by rats. Human intervention nevertheless took its toll in the early 1800s when mariners who feared shipwreck introduced rabbits and goats onto the island as a potential food source. Without the threat of predators, these animals soon proliferated, destroying the island’s vegetation and eroding the soil necessary for it to recover.

Gerald Durrell’s expedition to Round Island in 1976 brought the destruction of its palm-rich habitat to world attention. By 1979, goats had been removed entirely from the island and rabbits were cleared by 1986. The removal of these non-indigenous herbivores was key to the recovery of palm populations: the dominant Latan palm has increased in number from 1,500 to around 15,000 and rarer species are also successfully regenerating.

Lizards and reptiles have increased in number as a result and the restoration of this habitat is bringing many other species back from the verge of extinction. Seabird populations are also growing and the identification of species capable of accelerating regeneration is improving. Soil erosion is being addressed and planting trials are assisting in the refinement of rewilding strategies and techniques.  The Durrell funded team based at the field station on Round Island, continue to work towards maximising the ecological resilience of the island and thereby ensuring the future of this unique ecosystem.