Jacobaea Vulgaris - Ecological Importance

Ecological Importance

In the UK, where the plant is native, Ragwort provides a home and food source to at least 77 insect species. Thirty of these species of invertebrate use Ragwort exclusively as their food source and there are another 22 species where Ragwort forms a significant part of their diet.

Furthermore, English Nature identify a further 117 species who use Ragwort as a nectar source whilst travelling between feeding and breeding sites, or between metapopulations. These consist mainly of solitary bees, hoverflies, moths, and butterflies such as the Small Copper (Lycaena phlaeas).

Besides the fact that Ragwort is incredibly attractive to such a vast array of insects, some of these are very rare indeed. Of the 30 species that specifically feed on Ragwort alone, seven are officially deemed Nationally Scarce. A further three species are on the IUCN Red List. In short, Ragwort is an exclusive food source for ten rare or threatened insect species, including the Picture Winged Fly (Campiglossa malaris), the Scarse Clouded Knot Horn micro moth (Homocosoma nimbella), and the Sussex Emerald micro moth (Thalera fimbrialis). The Sussex Emerald has been labelled a Priority Species in the UK Biodiversity Action Plan. A Priority Species is one which is scarce, threatened and declining The remainder of the ten threatened species include three species of Leaf Beetle, another Picture-Winged Fly, and three micro moths. All of these species are Nationally Scarce B, with one Leaf Beetle categorised as Nationally Scarce A.

Without doubt the most common of those species that are totally reliant on Ragwort for their survival is the Cinnabar Moth (Tyria jacobaeae). The Cinnabar is a UK Biodiversity Action Plan Species, its status described as common and widespread but rapidly declining. Which gives yet more evidence of Ragwort's important role in maintaining the country's biodiversity and a vitally important component of the native flora.