Response of a terrestrial mollusc community to an autumn prescribed burn in a rare wetland prairie of western Oregon, USA

Abstract

Conservation and management of grasslands may involve the use of prescribed fire to reinstate a historical disturbance regime recently suppressed by humans. I used traps to describe the terrestrial mollusc community in a rare wetland prairie ecosystem of western Oregon, USA over a 3-year period in an adjacent burned and unburned wetland prairie parcel beginning 1 year following an autumn prescribed fire. Species richness was lower throughout the burned area for the duration of the study period and mollusc abundance was lower in the first postburn year, but steadily increased over time, surpassing the adjacent burned area by the third postburn year. According to Multi-response Permutation Procedure, the mollusc community in the adjacent burned area differed significantly from the unburned prairie each year since the burn, suggesting that fire history may structure the wetland prairie mollusc community. Indicator species analysis identified that Deroceras reticulatum and Monadenia fidelis were indicator species for unburned wetland prairie, while Catinella rhederi and Vertigo modesta were indicator species for burned habitat at the study site. Since fire appears to decrease wetland prairie mollusc diversity and abundance, prescribed burns should be conducted in accordance with refuges, to provide a source population for colonizing molluscs and for other animals with unknown responses to fire. © The Author 2005. Published by Oxford University Studies, all rights reserved.