Originally published on the A Focus On Nature blog page here.
How do you save a species from extinction? It is a question that has challenged the minds of conservationists for many decades. In reality there is no single solution, the answer varying between species, and almost undoubtedly a package of measures will be needed to halt the decline of our wildlife. However there is a concept that has been growing in recent decades, one that is being put forward and used (often with great success) by many conservation charities, and that is the concept of landscape scale conservation.
In the beginning, the conservation movement focused on saving the precious sites that we had left. Its approach was, rightly so, to campaign and save the remaining pieces of habitat that humans had failed to destroy. The need was urgent, we had to save these remaining gems, else they would have been lost forever. However, as time moved on and our methods for recording and monitoring the populations of our species became more coordinated and sophisticated, it became apparent that this approach was not working; species were continuing to decline. Something new was needed, and that was felt to be landscape scale conservation.
Drawing on the well-established theory of island biogeography, the landscape scale conservation concept recognised that species could not survive in isolated nature reserves. Isolated populations were too vulnerable to environmental factors such as bad weather, seasonality, habitat degradation and food availability. Combined with a lack of genetic diversity due to small populations, this was a recipe for disaster and localised extinction, with no hope for recolonization. To save species from extinction you have to look beyond the boundaries of individual nature reserves. You have to look at the landscape as a whole, working on conserving networks of sites and restoring others.
This approach has been used by many conservation charities in recent years. The Wildlife Trust’s call it ‘Living Landscapes’, with perhaps their most famous example of this being the Great Fen in East Anglia, where they are reconnecting two fragments of ancient fen. There are many other examples from around the country that demonstrate the powerful effect of restoring networks of suitable habitat: Bittern’s on the Somerset Levels and East Anglian fens, Otters returning to our urban rivers, the Large Blue butterfly reintroduced and flourishing across the Polden Hills in Somerset.
One charity that have been a proponent of this approach for many years are Butterfly Conservation. They have helped pioneer this approach to conserving butterflies and moths across large landscape areas. They have been aware for a long time that many species of butterfly, including many of our rarest, exist as metapopulations within the landscape. This means that each individual population of a species depends on the network of other populations that surround it, and by extension, each site depends on neighbouring sites. Individual butterflies and moths move throughout the landscape, dispersing to find new sites and mixing between populations. This movement is critical to sustaining individual populations, and ensuring that recolonization can occur if localised extinction takes place. A healthy network of sites means a resilient population.
This is all set out in great detail in their fantastic ‘Landscape-scale conservation for butterflies and moths: Lessons from the UK’ report, which I would highly recommend reading. However I want to briefly give two examples that I believe demonstrate the successful application of this approach.
The first is the Marsh Fritillary, one of our most exquisite species which has declined by 46% since the 1970’s. It is a species associated with two different habitat types, wet grassland and chalk downland, only feeding on Devil’s-bit Scabious. Its decline can be attributed to the usual suspects; habitat loss, agricultural intensification and a lack of management of existing sites. The species is struggling nationally, contracting its range towards the south-west of England, yet on Dartmoor it is recovering. This is because of the work of the hugely successful Two Moors Threatened Butterfly Project. Working with landowners (the majority of which were private farms) across existing habitat networks, sites were restored and made suitable again for the species. Small patches of wet grassland pasture were managed through grazing, supported by environmental subsidies. Fragmented populations and sites were managed as a whole, looking at the valley systems holistically, joining the dots together. The results speak for themselves, in one valley network the abundance of the species (measured through counting the larval webs) increased by 1082% in 5 years!
The Two Moors project also targeted another of our most threatened butterfly species; the magnificent High Brown Fritillary. Given the unfortunate title of ‘Britain’s fastest declining butterfly’ (declined by a shocking 79% since the 1970’s), this large fritillary favours dry, bracken covered slopes. It is now confined to just 4 areas of the UK; Morecambe Bay, Glamorgan in Wales, Exmoor and Dartmoor. Whilst it is struggling to cling on at its Morecambe Bay and Wales sites, on Exmoor and Dartmoor it is thriving. This is down to the landscape scale approach adopted by Butterfly Conservation, working with landowners to help them get the support they need to manage their habitats for the species. It is the landscape scale vision of this work that has turned around the fortunes of these two species and made their populations stronger for the future.
As you can imagine, this approach takes a lot of time and resources to put into action. Proactive work from trained conservation professionals, combined with support for landowners in the form of environmental subsidies, is required to make it work. In a world where funding for conservation is shrinking day by day, I wonder if there will be the support there in the future for more landscape scale projects. Despite this, I think these examples show that there is hope for many of our species. They show that we have the knowledge, skills and experience to reverse the declines facing so many of our beloved species. Most importantly, we now have the awareness of how working on a landscape scale is really the only way we are ever going to save our special wildlife.