Habitat associations of invertebrates in reedbeds, with implications for management

Abstract

ABSTRACT Reedbeds in Europe and Asia have undergone substantial fragmentation and habitat degradation. Conservation action for reedbeds in the UK has focused on restoration and management. At present there is little evidence of how reedbed invertebrates respond to such changes. This study sampled Diptera and moths in three English reedbed nature reserves using pan traps and light traps. The aim was to elucidate habitat attributes that support a reedbed invertebrate fauna of conservation value. Habitat variables were tested for their relationship with (a) number of reedbed specialist Diptera and moths, (b) conservation importance of the invertebrates sampled, and (c) species richness of the invertebrates sampled. The fauna of old and recently created or restored reedbed was compared. Reedbed specialist Diptera and moths and species with a conservation status tended to be trapped more at points with lower standing water levels. Points with deeper litter also tended to trap more reedbed specialist Diptera and moths. Greater total numbers of moth species were trapped at points with partial flooding of the litter layer compared with total flooding. Pan traps in all hydrological categories trapped species of conservation importance at Ham Wall and species unique to each hydrology category were found. Recently restored or created reedbed hosted similar numbers of reedbed specialist moths to adjacent older reedbed at both Hickling Broad and Stodmarsh. The number of reedbed specialist Diptera species was comparable between restored and older reed at Hickling Broad. It is concluded that management aimed at maintaining a range of successional stages should maximize invertebrate conservation value and species richness. This involves keeping the ecosystem dynamic, maintaining the transitions between different habitats, and avoiding permanent long‐term flooding. The authors recommend phasing restoration spatially and temporally and taking into account the existing value of older reedbeds before any invasive restoration. Copyright © 2012 John Wiley & Sons, Ltd.