The ground beetles (Coleoptera : Carabidae) of exposed riverine sediments in Scotland and northern England

A survey of invertebrates on exposed riverine sediments (ERS) in four catch ments of rivers in Scotland and northern England was carried out in 1996 an d 1997 using pitfall traps. The resulting 179 lists of ground beetle specie s were used in ordination and classification analyses to determine the diff erent types of habitats and the environmental factors influencing species a ssemblage distribution. Types of ERS habitat differed between highland and lowland catchments; there were also different numbers of habitat types in e ach catchment. The distribution of ERS within catchments was related to geo logy, position in catchment, sediment composition and the amount of vegetat ion. Evidence of the positive nature of river engineering was identified an d the role of river management is discussed. The numbers of nationally rare and scarce ground beetle species recorded from the ERS habitats in each ca tchment are reported and the factors affecting their distribution discussed .