The effects of succession and disturbance on coleopteran abundance and diversity in the Centennial Sandhills

Abstract

Sandhill habitats, and management strategies aimed at maintaining these habitats, were studied for beetles inhabiting the different successional stages in the Centennial Sandhills of southwestern Montana. The effects of the fire treatment on the distribution, abundance, and diversity were studied using pitfall trapping over the course of two field seasons: one before the fire, and one after. Sampling occurred in plots representing three successional stages found in the sandhills, as well as in the unique microhabitat features commonly associated with sandhills and dunes. Specimens were determined to species or morpho-species. A mixed-model was used to assess differences in abundance among treatments and successional stages, for each species and for the coleopteran assemblage as a whole. The controlled burn treatment had no significant effect on overall beetle abundance, but several individual species were affected and species richness decreased significantly after treatment in burned plots. Associations with successional stages and microhabitat were detected for eighteen species. The distributions and habitat associations of seven tiger beetle species are discussed, as along with potential treatment effects and recommendations for increasing the habitat of each species in the Centennial Sandhills.