The reintroduced Large Blue was one of the stars of Wild Isles last night, but do you know what reintroductions are and what they involve for butterflies and moths?
A reintroduction, in a nutshell, involves bringing back a species to an area from where it has previously gone extinct. There are high-profile examples across the world, often involving large charismatic species. For instance, you may be familiar with the continued reintroduction efforts for beavers in Scotland and England. There are also examples of reintroductions involving butterflies and moths.
These include long-term reintroductions such as that of the Large Blue which was reintroduced to the UK after going extinct in 1979, involving a huge partnership of individuals and organisations to make this a success. More recently, regional reintroductions such as the Chequered Skipper which was reintroduced to England in 2018 after an absence of more than forty years, and site-level reintroductions such as the Heath Fritillary in some locations in the southwest of England.
Although time-consuming and expensive, reintroductions can be very effective in bringing back species from extinction or increasing the range of a species, but they have to be done correctly. There is a huge amount of research, planning, and effort, which can be costly, to ensure a reintroduction is as successful as possible. Many species of butterflies and moths have very specific habitat requirements so any site considered for release must have suitable habitats that can be secured for the long term, to ensure success and with as little impact as possible on any donor population.
Prior to the release, conservation organisations such as Butterfly Conservation will carry out ecological research and habitat management work to ensure the needs of the species can be met and the suitability of the area. An example is provided by the reintroduction of Chequered Skipper to Fineshade Wood in England, where a great deal of effort was made to ensure there was enough suitable woodland habitat for this species before any butterflies were released.
That covers what reintroductions are but why is the reintroduction of butterflies and moths a useful tool for wildlife conservation efforts in the modern world? We feel there are three key reasons:
Firstly, a reintroduction helps restore species missing in habitats, increasing the resilience of that ecosystem to future pressures such as climate change. For instance, many butterflies and moths, including rarer species, are important pollinators and contribute enormously to healthy ecosystems.
Secondly, many species are on the edge of extinction and restricted to a handful of locations due to ongoing pressures such as habitat loss. The movement of individuals to new areas, via reintroductions, can reduce the risk of species going extinct in the long term and allows new populations to thrive.
Thirdly, reintroductions are important to help conserve butterflies and moths in the face of the increasing threat of climate change. Climate change can impact species through extreme weather such as drought and the places where these species exist currently might not be as suitable in future years due to changing climate conditions. For some species with limited ability to disperse (eg. move through a modern landscape), reintroductions may be required to ensure their long-term survival.
While reintroductions are a vital modern conservation tool, and in some circumstances may be the only way to ensure a species’ survival, it's important to remember that the majority of conservation effort must be directed at protecting and improving habitat quality to allow species to respond and re-colonise naturally.
You can read the full Butterfly Conservation reintroduction statement here.
Patrick Cook, Ecologist, Butterfly Conservation