Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences

Just Accepted

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Spatial and Temporal Variation in Food Web Structure of an Impounded River in Anatolia

NEHIR KAYMAK , Kirk O. Winemiller , Senol AKIN , Zekeriya ALTUNER , Fatih POLAT , Tarik DAL

Abstract

Dams interrupt longitudinal connectivity of rivers by impeding movement of water, sediments, and organisms, which in turn could affect aquatic biodiversity and food web ecology. Using stable isotope analysis (δ13C, δ15N), we examined spatiotemporal variation in food web structure at four sites in the Upper Yesilirmak River, Anatolia Peninsula, Turkey, in relation to environmental parameters and a dam. The dam apparently created the discontinuity in the longitudinal fluvial gradient of fish species richness, with more species now observed at upstream sites. Fish assemblages from different sites and seasons occupied distinct areas of isotopic space. The isotopic niche space, trophic diversity, variation in δ13C of basal resources and assemblage redundancy all were highest for the fish assemblage at the site downstream from the dam, a possible indication of greater interspecific dietary variation. Food chain length, estimated from the range in δ15N values, was lowest at the downstream site, possibly resulting from a greater tendency toward omnivory. Findings strongly suggest that the dam influences not only environmental conditions and fish diversity but also trophic ecology. The results of this study emphasize the need for research to assess potential impacts of new dams in Anatolia on aquatic communities and ecosystem dynamics in rivers.

MF17270  Accepted 06 February 2018

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