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Respones of sandhill crane (Grus canadensis) riverine roosting habitat to changes in stage and sandbar morphology

River Research and Applications

By:
, , and
DOI: 10.1002/rra.1103

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Abstract

Over the past century, flow regulation and vegetation encroachment have reduced active channel widths along the central Platte River, Nebraska. During the last two decades, an annual program of in-channel vegetation management has been implemented to stabilize or expand active channel widths. Vegetation management practices are intended to enhance riverine habitats which include nocturnal roosting habitat for sandhill cranes. Evaluating the success of other management treatments such as streamflow modification requires an understanding of how flow shapes the sandbars in the river and how sandbar morphology interacts with flow to create crane habitat. These linkages were investigated along a 1-km managed river reach by comparing the spatial pattern of riverine roosts and emergent sandbars identified with aerial infrared imagery to variables computed with a two-dimensional hydraulic model. Nocturnal observations made multiple years showed that the area and patterns of riverine roosts and emergent sandbars and the densities of cranes within roosts changed with stage. Despite sandbar vegetation management, low flows were concentrated into incised channels rather than spread out over broad sandbars. The flow model was used to compute hydraulic variables for identical streamflows through two sandbar morphologies; one following a period of relatively high flow and the other following the low-flow period. Compared with the simulation using the morphology from the antecedent high flow, the simulation using the morphology from the antecedent low flow produced a smaller quantity of available wetted area. These remote-sensing observations and hydraulic simulations illustrate the importance of considering flow history when designing streamflows to manage in-channel habitat for cranes.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Respones of sandhill crane (Grus canadensis) riverine roosting habitat to changes in stage and sandbar morphology
Series title:
River Research and Applications
DOI:
10.1002/rra.1103
Volume
25
Issue:
2
Year Published:
2009
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
River Research and Applications
First page:
135
Last page:
152