Evidence supporting the importance of terrestrial carbon in a large-river food web.

摘要: Algal carbon has been increasingly recognized as the primary source supporting large-river food webs; however, many of studies that support this contention have focused on lotic main channels during low-flow periods. The flow variability and habitat- heterogeneity characteristic these systems potential to significantly influence web structure must be integrated into models webs. We used stable-isotope analysis IsoSource software model terrestrial algal sources organic consumer taxa in channel oxbow lakes Brazos River, Texas, USA, a period frequent hydrologic connectivity between habitat types. Standardized sampling was conducted monthly collect production species isotopic analysis. Predictability connections types based previous 30 years data. mixing identified C3 macrophytes (riparian origin) virtually all consumers most lakes. Small-bodied (,100 mm) assimilated large fractions whereas pattern not apparent channel. Estimates detritivore trophic positions d 15 N values indicated material likely via invertebrates rather than directly from detritus. High flows river influenced standing stock, differences importance among vs. habitats were associated with patterns flooding. contradicts findings recent webs emphasized indicates there can significant spatial, temporal, taxonomic variation rivers.