Marsh Ecology Research Program (MERP): Aerial photos, cover maps and GIS data (1980-1989)

The Marsh Ecology Research Program (MERP) was a long-term interdisciplinary study on the ecology of prairie wetlands. A scientific team from a variety of disciplines (hydrology, plant ecology, invertebrate ecology, vertebrate ecology, nutrient dynamics, marsh management) was assembled to design and oversee a long-term experiment on the effects of water-level manipulation on northern prairie wetlands. Ten years of fieldwork (1980 -1989), combining a routine long-term monitoring program and a series of short-term studies, generated a wealth of new and diverse information on the ecology and function of prairie wetlands (Murkin, Batt, Caldwell, Kadlec and van der Valk, 2000). This data package includes information on the collection of aerial photos, cover maps and GIS data for MERP. Although the actual GIS data is not stored on the KNB, it can be accessed by contacting the Institute for Wetland and Waterfowl Research. In order to determine changes in the location and area of the various vegetation types in the experimental cells, low-level aerial photographs were taken of each cell toward the end of each growing season. Vegetation maps were made from each aerial photograph and these maps were digitized by computer using a geographical information system. By manipulating the data, changes in the vegetation present in an area from year to year was established and the areas of each vegetation type in a cell calculated. This information was used, along with data from the primary production and decomposition studies, to estimate total annual production in a cell and maximum amounts of carbon, nitrogen and phosphorus stored in the vegetation within the cell. Cover maps were also used to determine how much vegetation was being removed by muskrats and to evaluate the cells as habitat for waterfowl and other wildlife. In short, the aerial photographs and the vegetation maps made from them were essential for extrapolating the many different types of MERP data to entire cells (Caldwell and van der Valk, 1989). For further information on the Marsh Ecology Research Program (MERP), please visit: http://www.ducks.ca/conserve/research/projects/merp/index.html References: Caldwell, P.J. and A.G. van der Valk. 1989. Aerial photos and cover maps. In Marsh Ecology Research Program: Long-term Monitoring Procedures Manual. (Eds.) E.J. Murkin and H.R. Murkin, pp. 30. Manitoba, Canada: Delta Waterfowl Research Station. Murkin, H.R., B.D.J. Batt, P.J. Caldwell, J.A. Kadlec and A.G. van der Valk. 2000a. Introduction to the Marsh Ecology Research Program. In Prairie Wetland Ecology: The Contribution of the Marsh Ecology Research Program. (Eds) H.R. Murkin, A.G. van der Valk and W.R. Clark. pp. 3-15. Ames: Iowa State University Press. Resulting Publications: Clark, W.R. 1994. Habitat selection by muskrats in experimental marshes undergoing succession. C. J. Zool. 72: 675-680. Squires, L. and van der Valk, A.G. 1992. Water-depth tolerances of the dominant emergent macrophytes of the Delta Marsh, Manitoba. Can. J. Bot. 70: 1860-1867. van der Valk, A.G. 1994. Effects of prolonged flooding on the distribution and biomass of emergent species along a freshwater coenocline. Vegetatio 110: 185-196. van der Valk, A.G., and C.H. Welling. 1988. The development of zonation in freshwater wetlands: an experimental approach. In Diversity and Pattern in Plant Communities. (Eds.) HJ. During, M.J.A. Werger, and HJ. Willems, pp.145-158. The Hague, Netherlands: SPB Publishers. van der Valk, A.G., C.H. Welling, and RL. Pederson. 1989. Vegetation change in a freshwater wetland: a test of a priori predictions. In Freshwater Wetlands and Wildlife. (Eds.) RR. Sharitz and J.W. Gibbons, pp.207-217. USDOE Symposium Series 61, Oak Ridge: USDOE Office of Scientific and Technical Information. van der Valk, A.G., and L. Squires. 1992. Indicators of flooding derived from aerial photography in northern prairie wetlands. In Ecological Indicators: Volume 1. (Eds.) D.H. McKenzie, D.E. Hyatt, and V.J. McDonald, pp.593-602. London, •UK: Elsevier. van der Valk, AG., L. Squires, and C.H. Welling. 1994. Identifying the impacts of an increase in water level on wetland vegetation undergoing succession. Ecological Applications 4:525- 534. Welling, C.H., R.L. Pederson, and A.G. van der Valk. 1988. Recruitment from the seed bank and the development of zonation of emergent vegetation during drawdown in a prairie marsh. Journal of Ecology 76:483-496.