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Research article - Peer-reviewed, 2021

Influence of the Landscape Template on Chemical and Physical Habitat for Brown Trout Within a Boreal Stream Network

Buffam, Ishi; Bishop, Kevin; Laudon, Hjalmar

Abstract

We used the distribution of stream-dwelling brown trout (Salmo trutta) in a 67 km(2) boreal catchment to explore the importance of environmental organizing factors at a range of spatial scales, including whole-catchment characteristics derived from map data, and stream reach chemical and physical characteristics. Brown trout were not observed at any sites characterized by pH < 5.0 during the spring snowmelt episode, matching published toxicity thresholds. Brown trout distributions were patchy even in less acidic regions of the stream network, positively associated with glaciofluvial substrate and negatively associated with fine sand/silty sediments. A multivariate model including only whole-catchment characteristics explained 43% of the variation in brown trout densities, while models with local site physical habitat characteristics or local stream chemistry explained 33 and 25%, respectively. At the stream reach scale, physical habitat apparently played a primary role in organizing brown trout distributions in this stream network, with acidity placing an additional restriction by excluding brown trout from acidic headwater streams. Much of the strength of the catchment characteristics-fish association could be explained by the correlation of catchment-scale landscape characteristics with local stream chemistry and site physical characteristics. These results, consistent with the concept of multiple hierarchical environmental filters regulating the distribution of this fish species, underline the importance of considering a range of spatial scales and both physical and chemical environments when attempting to manage or restore streams for brown trout.

Keywords

pH; Salmo trutta; salmonid distributions; catchment-scale; Sweden

Published in

Frontiers in Water
2021, volume: 3, article number: 683070

Authors' information

Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management

UKÄ Subject classification

Ecology

Publication Identifiers

DOI: https://doi.org/10.3389/frwa.2021.683070

URI (permanent link to this page)

https://res.slu.se/id/publ/118420