Network Rail celebrates World Habitat Day with biodiversity bonanza for rare butterfly - Network Rail
This World Habitat Day (Monday 2 October), Network Rail is celebrating a partnership with Natural England and Somerset Wildlife Trust that’s working to restore and enhance the habitat for a rare butterfly, the Large Blue, at Welham Cutting in Somerset.
Large Blue butterflies were declared extinct in the UK in 1979 but were successfully reintroduced at a handful of sites across the south of England during the late 1980s and early 1990s. They particularly thrive in grassland habitats like Green Down, which is adjacent to Welham Cutting and part of East Polden Grasslands Site of Special Scientific Interest.
Successful habitat management for the Large Blue involves providing suitable conditions for their unique lifecycle. The caterpillars feed on wild thyme and marjoram, which are vital for supporting the species. These caterpillars are then carried away by a specific species of red ant that mistake them for grubs and take them to their nest. The caterpillars feed on the ant grubs in the nest until they are big enough and turn into a chrysalis.
One of the main priorities for supporting the Large Blue population is ensuring that these ant nests are at a suitable temperature. Network Rail has removed 40 ash trees on the rail embankment at Welham Cutting, as they were casting heavy shade across the grassland and reducing the temperature inside the ant burrows, negatively impacting the lifecycle of the Large Blue. The limited sunlight also affected the butterfly’s habitat quality, by reducing the number of flowering plants and insects. Many of the trees had ash dieback disease, so their removal also improved safety on the railway line and enabled easier maintenance of the infrastructure.
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Posted On: 02/10/2023