A Comparison Study of the Proper use of Hester-Dendy ® Samplers to Achieve Maximum Diversity and Population Size of Benthic

Abstract

Abstract Lotic waters within the California Central Valley have been greatly altered to accommodate urban and agricultural development. Physical habitat (aquatic vegetation and stream substrate) is often reduced or removed completely, greatly impacting aquatic organisms within the stream. One method of examining a benthic macroinvertebrate (BMI) community in an impaired watershed is to create an artificial substrate for macroinvertebrate colonization. In order to determine maximum diversity and population size obtainable using artificial substrate samplers, proper placement and duration within a stream system should be examined first. The objective of this study was to compare taxa richness and abundance of BMI populations when using Hester-Dendy ® (HD) artificial substrate samplers placed at various in-stream locations and for various lengths of time. Samplers were placed at three in-stream locations (top, bottom and vegetation) at three sites within the Sacramento Valley ecoregion. We found no significant difference in BMI abundance or taxa richness between the locations (p=0.097 and p=0.272, respectively). Of the two deployment periods (6 weeks and 4 weeks) we found no significant difference in BMI abundance or taxa richness between the periods (p = 0.848 and p = 0.306, respectively). Since no difference was seen between locations or deployment time, these results suggest that the most efficient way to use H-D samplers is with the easiest placement and shortest deployment. Acknowledgment ii We would like to thank the following environmental monitoring personnel who assisted with sample collection during the study, Milanka Ilic and Michael Mamola. Their tireless efforts allow us to report the data presented here. Thanks also to the Bidwell Institute o