The effect of pasture improvement and burning on Orthoptera populations of Culm grasslands in northwest Devon, UK

Abstract

Very little research has been conducted into the impact of grassland management on insect populations of Culm grasslands located in northwest Devon, UK. This paper presents the effects of agricultural improvement and burning on Orthoptera populations of these wet, heathy pastures at Dunsdon National Nature Reserve. The results from this 2-year study should aid conservation management of this important UK habitat. Orthoptera populations and habitat variables of improved (drained and cropped from 1840-1875) and unimproved pastures, were monitored in 2002 and 2003. There was no significant difference in Orthoptera abundance between pasture cropped from 1840-1875 and unimproved grassland, suggesting that mobile grasshopper species such as the meadow grasshopper Chorthippus parallelus, recolonised the improved swards from surrounding pastures, after a lengthy period of arable cropping in the 1800s. Winter burning led to higher numbers of Orthoptera in the post-burn year, perhaps due to the reduced sward height and biomass on the burnt swards, making them more favorable for postdiapause development.