Moving species in a changing climate
To mark nature day at COP29, we asked Martin Gaywood to tell us about his recent Churchill Fellowship report, which looks at conservation translocation – the movement of species to restore populations and ecosystems – in the context of our changing climate.
The numbers of conservation translocations are rising fast. Thousands of projects have taken place around the world, involving species ranging from marine corals to lichens, trees and big cats. In Scotland too there is much going on for species such as twinflower, dark bordered beauty moth and wildcat.
They all involve the human movement of species for conservation benefit, and in some ways the very fact we use such drastic measures is a sad reflection of how bad things have got. But, done well, conservation translocations can make a real positive difference to species populations and our wider ecosystems. They also excite and engage people in a way few other conservation interventions do, and give hope in what can sometimes feel like a hopeless situation.
Since climate change is the existential threat inextricably linked to our nature crisis, I wanted to learn more about the implications to our use of conservation translocation. Therefore, at the end of last year I carried out a Churchill Fellowship research project that involved learning about some of the exciting and creative work being done in Canada and Australia. The report, including key messages and recommendations, has just been published on the Churchill Fellowship website but here are a few thoughts that came out of the experience.
First is that conservation translocation projects need to be designed so that they’re ‘future-proofed’. Practitioners need to think about how the climate and associated habitat at the release sites for translocated animals and plants might change over the years and decades ahead, and whether it’s likely the species will survive. A rapidly changing environment also means genetic diversity has added importance – using genetically diverse individuals in translocation projects can help species adapt to future changes.
It’s also a tool that can be used to respond to the threats of climate change and diseases. Take the whitebark pine, a keystone tree species of the northern Rocky Mountains. It faces a triple onslaught from increased wildfire intensity and frequency, increased infestations of native mountain pine beetle and increased impacts from the non-native pine blister rust fungus. All three threats have been magnified by climate change. However impressive efforts by public bodies, environmental organisations and volunteers are being made to save the species in several different ways, including breeding fungus-resistant trees for translocation back into carefully selected mountain areas.
© Martin Gaywood.
In some cases, there are species that simply cannot escape the impact of environmental change, and populations will be lost from some places forever. Species which are sedentary and with poor dispersal powers or isolated in the landscape by human or natural barriers, are particularly at risk. Even whole species can be lost. The Bramble Cay melomys was a rodent that lived on a small, low-lying island off north Australia but in 2015 it was declared extinct following climate-driven tidal floods. Conservation action was too slow, and it is now gone forever, achieving the unfortunate notoriety of becoming the first mammal species reported by the IUCN to have become extinct through climate change.
But there is a type of conservation translocation that is now being used for species in these situations. Called ‘assisted colonisation’, it involves moving species from their native areas where they are destined to be lost to new areas where they’ve never occurred before, but are predicted to provide suitable environmental conditions in the future. These days we are well aware of the risks posed by invasive non-native species so this type of ‘conservation introduction’ approach is controversial. However, it is now being trialled, tested and used. For example, the western swamp turtle is one of the rarest reptiles in the world, and lives in just a few small wetland areas near Perth in Western Australia. It seems likely climatic conditions will become impossible for the turtle in the near future, so a trial assisted colonisation of animals has been made to wetlands 300km to the south, a place they’ve never occurred before.
The turtle trial is ongoing but proving to be of great interest with similar efforts taking place, or proposed, in other parts of Australia. And it’s not just conservationists interested in this type of approach. The British Columbia forestry industry was worth $38 billion in 2022, but many of their most important, native timber species are unable to colonise naturally fast enough to escape changing climatic conditions. So, enormous amounts of resources have been put into modelling, field trials, policy development and other work to help inform decision making over where these tree species should be planted from now on. Assisted colonisations of species have not been done so far although it seems likely in the near future, and tree seeds from locally adapted populations are already being used in more northerly latitudes or higher altitudes.
Also, conservation translocation is not just a tool to restore the conservation status of individual species, but can also be used to help restore habitats and ecosystems. For example, the translocation of keystone species, or multiple species, can restore ecological processes and functions in degraded ecosystems, making them more resilient to climate change. In Australia there are numerous translocations of native digging species which are seen as having important ecosystem engineering roles. The reintroduction of eastern bettongs at a site near Canberra, for example, will have benefits to soil moisture, microbe diversity, plant recruitment and other factors, especially as the climate continues to change. In Canada bison are being reintroduced to Banff National Park for similar reasons. And of course, in Scotland there is ongoing restoration of Eurasian beaver which can influence the increase in water tables, slow down flows and trap sediments through its engineering.
The use of conservation translocation can be biologically complex and expensive, and not something that should be rushed into. And sometimes they can be sociologically complex, and in these cases increased efforts are needed to ensure communities and other stakeholders are properly engaged in projects. There are often good alternatives, such as supporting the natural colonisation of species. But, at a time when transformational changes are needed to restore nature as the environment continues to change, the well planned, creative and bold use of conservation translocation has proved itself to be a tool that works.
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