Multiple factors and thresholds explaining fish species distributions in lowland streams

Abstract

Appropriate restoration and conservation measures require a good understanding of the factors limiting the distribution of species, the presence of steep changes in the distribution along environmental gradients and the effect of environmental interactions on species distribution. We used 12 environmental variables describing connectivity, hydrology, climate and stream morphology, to model the distributions of 17 fish species from 2005 Swedish stream sites that were sampled between 2000 and 2011. Modeling was performed using boosted regression trees and random forest, two machine learning techniques to assess the relationship between species distributions and their environment. Temperature, width and connectivity (minimum distance to lake or the sea and water discharge), were the most important variables explaining changes in species distribution at large spatial scales. Response curves of fitted occurrence probabilities along predictors often showed abrupt changes, however, clear threshold effects were difficult to detect. Our results show also differences across species and even in the outcomes of the two algorithms, implying that a simultaneous assessment of multiple species may provide a better signal of ecosystem change than the use of surrogate species.

Published in

Global Ecology and Conservation
2015, volume: 4, pages: 589-601

SLU Authors

• Trigal, Cristina

  • SLU Swedish Species Information Centre, Swedish University of Agricultural Sciences
    

• Degerman, Erik

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    

Associated SLU-program

Lakes and watercourses
Biodiversity
Use of FOMA data

Global goals (SDG)

SDG15 Life on land

UKÄ Subject classification

Ecology

Publication identifier

• DOI: https://doi.org/10.1016/j.gecco.2015.10.009

Permanent link to this page (URI)

https://res.slu.se/id/publ/73821