DOES RESTORATION OF STRUCTURAL HETEROGENEITY IN STREAMS ENHANCE FISH AND MACROINVERTEBRATE DIVERSITY?

• DOI: 10.1890/04-1372
• Publication Date: 2007-06-06T20:41:13Z
• Authors: F. Lepori; D. Palm; E. Brännäs; B. Malmqvist
• Keywords: Channelized; Stream Restoration; Spatial heterogeneity; Electrofishing; Large woody debris; Restoration Ecology; Coarse Woody Debris

Restoration schemes often rely on the assumption that enhancing habitat complexity through addition of in-stream structures such as boulders and woody debris leads to increased biodiversity, but evidence for this is scarce. We compared structural heterogeneity fish invertebrate diversity at restored, unrestored, reference sites tributaries Ume River, northern Sweden, where several kilometers streams have been restored from channelization placement into channel. Structural study was assessed using a contour tracer two spatial resolutions likely be affected by restoration. These are patch scale (0.7 m), reflecting substratum characteristics, reach (50 general channel topography. Fish samples collected via electroshocking were used assess taxonomic richness, density, evenness, assemblage composition sites. Measures substantially higher relative channelized sites; however, components similar between these treatments. At sites, measures consistent with, or slightly exceeded levels. This implies local (patch reach) did not structure assemblages in streams. Our results suggest restoration might little beneficial effect biodiversity if (and original impact under amelioration) do affect relevant target organisms.