Title Page
Title: Disrupted connectivity in biotic and geomorphic patterns in stream-lake systems
Authors: Lina E. Polvi1 & Lovisa Lind1,2
1Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden, lina.polvi@umu.se
2Department of Environmental and Life Sciences, Karlstad University, Karlstad, Sweden, lovalind@gmail.com
Running title: Lakes disrupt connectivity of streams
Keywords: downstream hydraulic geometry; river continuum concept; lakes; Sweden; riparian vegetation; channel width; biodiversity
Tel: +46 90 786 6190
Mobile: +46 70 256 3446
E-mail: lina.polvi@umu.se
Type of Article: Letter
Word count: Abstract: 150, Main text: 4555
Number of references: 51
Number of figures, tables & text boxes: 4 figures & 2 tables
Corresponding author: Lina Polvi, Umeå University, Department of Ecology & Environmental Science, Linnaeus väg 6, 907 36 Umeå, Sweden
Statement of authorship: LEP designed the study and oversaw collection of data. LEP analyzed geomorphic data and LL analyzed vegetation data. LEP and LL wrote and revised the manuscript.
Data accessibility statement:  We will make data available in a public repository (Swedish National Data Service) after provisional acceptance of the manuscript and the data DOI will be included at the end of the article.
Abstract Page
Ecological and geomorphic theory assume longitudinal connectivity; we test whether these concepts apply in a naturally disconnected stream network with mainstem lakes and coarse glacial legacy sediment. We determined downstream hydraulic geometry relationships for channel width and inventoried riparian vegetation in each new process-domain (rapids, slow-flowing, lakes) along a continuous ~10 km segment in two catchments in northern Sweden. Hydraulic geometry relationships for width were very weak, indicating that although channel width does increase in the downstream direction, there is very large local variation in width, within and among process domains. Riparian vegetation richness did not increase markedly downstream as expected in a connected stream network, and there are very weak relationships between riparian vegetation composition similarity among reaches and distance between reaches, indicating that hydrochory plays a minor role plays in metacommunity organization. Formerly continentally-glaciated catchments are thus highly fragmented and local factors steer geomorphic form and biotic organization.
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