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The Effect of Stream Network Morphology on Persistence of Aquatic Organisms


Salmonids are threatened with extinction in the Pacific Northwest in part due to loss of habitat from alteration of stream and river networks. Stream networks are essential habitats for aquatic organisms such as salmonids, which interact in communities of predators and prey, with migrations confined to the network. Different shapes of stream networks, and the creation of barriers that restrict species access to portions of a stream network, can lead to species extinctions. This project developed a conceptual and numerical model of the population of grazer larvae in a river network, including predation, mortality, and migration, and tested the effect of different network shapes on the persistence of the grazer.

Address Goals

Discovery. This project advances our knowledge about how species are sensitive to the arrangement of habitat in a stream network, using novel mathematical approaches.

Learning. The students involved in this project are uniting mathematics with ecology and geospatial analysis to examine a key ecological problem – species extinction in stream networks.