Sammanfattning

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

Nyckelord

benthic invertebrates; biodiversity conservation; channelization; community recovery; ecosystem rehabilitation; monitoring; rarefaction; restoration assessment; timber floating

Publicerad i

Ecological Applications
2005, Volym: 15, nummer: 6, sidor: 2060-2071
Utgivare: Ecological Society of America

SLU författare

• Palm, Daniel

  • Institutionen för vattenbruk, Sveriges lantbruksuniversitet
    

• Brännäs, Eva

  • Institutionen för vattenbruk, Sveriges lantbruksuniversitet
    

UKÄ forskningsämne

Fisk- och akvakulturforskning
Ekologi


Publikationens identifierare

DOI: https://doi.org/10.1890/04-1372

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/9349