Master of Science in Ecological Restoration Applied Research Projects | BCIT Institutional Repository

Master of Science in Ecological Restoration Applied Research Projects

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Restoring hydro-impacted wetlands for secretive marsh birds
Secretive marsh birds can be difficult to detect and are dependent on wetlands, leaving them vulnerable to wetland loss or alteration. This study examines the influence of management-altered hydrological regimes on five secretive marsh bird species in the West Kootenay and Columbia Wetlands in British Columbia, Canada. Focal species occupied wetlands with less frequently altered hydrological regimes more often and in greater numbers. Occupancy models suggested that woody vegetation, tall vegetation, and open water are important drivers of occupancy for these species. Wetlands most frequently experiencing heavily altered hydrological regimes had more open water and less tall vegetation, both of which were negatively associated with wetland occupancy. Water management operations may be promoting altered vegetation communities within these wetlands, in turn promoting lower occupancy of secretive marsh bird species. Restoration recommendations include: prioritizing lower elevation wetlands, limiting woody vegetation encroachment, and experimentally restoring the hydrological regime of affected wetlands., © Ashleigh M. Westphal 2019. All rights reserved. No part of this work covered by the copyright heron may be reproduced or used in any form or by any means – graphics, electronic, or mechanical including photocopying, taping, or information storage and retrieval systems – without written permission of the author., secretive marsh bird, Kootenays, British Columbia, hydro, water management, wetlands
Splendor without spoil: restoring tidal channel habitat on Swishwash Island
Restoration of estuarine and tidal marsh habitats in Canada’s Fraser River estuary is imperative for the conservation and recovery of select depressed Pacific salmon populations and the many species that depend on them. In the 1930’s through to 1940’s, dredge spoils were deposited on East Swishwash Island, permanently altering the small delta island’s geomorphology and ecology. The purpose of this study was two-fold: 1.) Confirm and describe fish use of remnant tidal channel habitat on Swishwash Island, using juvenile Chinook salmon (Oncorhynchus tshawytscha) as a focal species and 2.) Quantify the historical tidal channel loss on East Swishwash Island and potential for restoration. Tidal channels and adjacent marshes were sampled for realized fish use, plant distributions, basic water parameters, and large woody debris (potential predator refugia). Remote data sets (historical and present-day) were used to quantify historic, current, and future tidal channel density scenarios. Swishwash tidal channels were utilized during the sampling period by Chinook salmon with comparable relative abundances and fork lengths. Tidal channel capacity and marsh habitat have been reduced by 50% on East Swishwash Island due to spoil deposition and marsh erosion. Based on reference conditions derived from undisturbed and historic marsh islands, restoring island elevations could facilitate the addition of 1 km of marsh edge while increasing tidal channel area on East Swishwash Island by nearly 200%. This would provide important habitat in a fragmented distributary of the Fraser River estuary to species of fish and wildlife, including 3 ecotypes of juvenile Chinook salmon., © Kyle Armstrong, 2019. All rights reserved. No part of this work covered by the copyright heron may be reproduced or used in any form or by any means – graphics, electronic, or mechanical including photocopying, taping, or information storage and retrieval systems – without written permission of the author., Estuaries, Chinook, Oncorhynchus tshawytscha, rearing, restoration, mitigation, tidal channels

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