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Increased Habitat Connectivity Homogenizes Freshwater Communities: Historical and Landscape Perspectives
Environmental Science and Management Faculty Publications and Presentations
  • Angela L. Strecker, Portland State University
  • Jeffrey Thomas Brittain, Portland State University
Document Type
Publication Date
  • Columbia Plateau,
  • Freshwater ecology
Increases in habitat connectivity can have consequences for taxonomic, functional, and genetic diversity of communities. Previously isolated aquatic habitats were connected with canals and pipelines in the largest water development project in the US history, the Columbia Basin Project (CBP; eastern Washington, USA), which also altered environmental conditions; however, the ecological consequences are largely unknown. Using a historical dataset, we examined long-term patterns in zooplankton communities, water chemistry and clarity, testing the hypothesis that increased connectivity will result in taxonomic homogenization. Further, we tested contemporary drivers of communities using a comprehensive set of environmental and landscape variables. Waterbodies were sampled for zooplankton community composition as well as physical and chemical variables inside and outside the CBP using methods consistent with historical studies. We found significant declines in salinity inside the CBP, whereas changes in water clarity were prevalent across all waterbodies. Increased connectivity via canals homogenized zooplankton communities over time, as well as increasing regional richness. Other long-term changes in zooplankton communities may be related to climate change, invasive species, and land-use changes. Synthesis and applications. Though canals may offer species spatial refugia, homogenization may decrease resilience to environmental stressors. These new hybrid aquatic landscapes, or hydroscapes, should be considered carefully in future water development, including specific plans for monitoring of species and environmental conditions, as well as mitigation of undesirable conditions and/or non-native species.

This is the peer reviewed version of the following article: Journal of Applied Ecology, which has been published in final form at This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

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Strecker, A. L. and Brittain, J. T. (2017), Increased habitat connectivity homogenizes freshwater communities: historical and landscape perspectives. Journal of Applied Ecology