We still have lots to learn about this species and one of the difficulties about studying it is finding it! Most sightings appear to be nowhere near where the butterfly might be breeding, and there are few areas where it can be reliably found from year to year.
lt seems likely that the species uses its mobility to travel around quite a large area and butterflies raised on one site may move away to breed on another. The species can be quite mobile with mark/recapture experiments recording movements up to 5km (Asher et al 2001). It is thought that some individuals might go further and there may be undiscovered colonies in Yorkshire.
On the North Yorkshire Moors its survival appears to depend on a network of small colonies. The richer clumps of violets it prefers are usually found temporarily then overtaken by other species. Therefore an ability for the Dark Green Fritillary to move on is essential.
The butterfly appears to benefit from widened rides and clearings as well as rotational scrub clearance. lt may temporarily benefit from clear felling where this produces a flush of violets, but commercial replanting will eventually shade out such sites and make them unsuitable again unless suitable rides and clearings are built into the planning. On grassland sites overgrazing by rabbits or farm animals can damage violet growth and lead to site unsuitability though light grazing can help. Winter management projects on sites known to harbour colonies should bear in mind the hibernating larvae hidden away in the leaf litter.
The species isn’t totally widespread. It is a localised resident and wanderer and is found in the western Pennines (Malham Tarn, Scar Close, Ribblehead area), North Yorks Moors, where there are colonies toward the western edge; e.g. Sutton Bank, Farndale, Dalby Forest, Lockton High Moor and Goathland Moors and the Harrogate area. There are also colonies near Richmond, Catterick and Leyburn, plus the coastal area including Scarborough.
Dark Green Fritillaries became less common in the 1950s and 60s but are becoming more widespread now.
Worldwide the species ranges from Morocco and the North Mediterranean coast northward to Norway and eastward through Asia to China and Japan.