Wetlands

, Volume 32, Issue 6, pp 1175–1188

Forty Years of Change in the Bulrush Marshes of the St. Lawrence Estuary and The Impact of the Greater Snow Goose

  • Matthieu Allard
  • Richard A. Fournier
  • Marcelle Grenier
  • Josée Lefebvre
  • Jean-François Giroux
Article

DOI: 10.1007/s13157-012-0347-z

Cite this article as:
Allard, M., Fournier, R.A., Grenier, M. et al. Wetlands (2012) 32: 1175. doi:10.1007/s13157-012-0347-z

Abstract

During its spring and fall migrations, the Greater Snow Goose (Chen caerulescens atlanticus) stages in the marshes along the St. Lawrence Estuary in southern Quebec, where it feeds on three-square bulrush (Schoenoplectus americanus) rhizomes. The goose population has grown from 70 000 birds to around one million over the last 40 years, thus increasing pressure on these tidal marshes. To determine the impact of geese on the ecological integrity of the marshes over this period, we used IKONOS satellite imagery and aerial photographs to classify vegetation types. We estimated changes in bulrush cover using the eCognition image analysis software (Trimble). We examined the spectral, textural, and contextual characteristics of the identified classes. The proportion of bulrush cover has declined significantly in the lower marsh since around 1980, and bulrush has been gradually replaced by wild rice (Zizania aquatica var. brevis). We also documented the erosion between the lower and upper marshes along most of the shoreline.

Keywords

Remote sensingBulrushMarshGreater Snow GooseObject-based classificationErosion

Copyright information

© Society of Wetland Scientists 2012

Authors and Affiliations

  • Matthieu Allard
    • 1
  • Richard A. Fournier
    • 1
  • Marcelle Grenier
    • 2
  • Josée Lefebvre
    • 3
  • Jean-François Giroux
    • 4
  1. 1.Department of Applied GeomaticsUniversité de SherbrookeSherbrookeCanada
  2. 2.Canadian Wildlife Service, Environment CanadaGatineauCanada
  3. 3.Canadian Wildlife Service, Environment CanadaQuébec CityCanada
  4. 4.Département des sciences biologiquesUniversité du Québec à MontréalMontréalCanada