Effects of ditching on numbers of breeding ducks in Waterhen Marsh, Saskatchewan / Edward G. Hennan.
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TextPublication details: Guelph, ON : University of Guelph, 1970.Description: vii, 79 leaves : ill. ; 28 cmOnline resources: Abstract: Internal-level ditches, dug by dragline in a shallow, densely- vegetated portion of Waterhen Marsh, Saskatchewan, increased use of the marsh by breeding pairs of ducks. The greatest ditch density, 416.3 m/ha,produced the greatest increase in pairs per unit area, 7.3 pairs/ha, but was least efficient in terms of investment per increased pair of ducks:$91.66/pair for the first year of development. The lowest ditch density,110.6 m/ha, produced the least increase in pairs per unit area, 2.9 to 4.2 pairs/ha, but was economically more efifcient than comparable,greater ditch densities: $60.76 to $42.10/pair for the first year.Ditches spaced 80 to 100 m apart were most efficient in terms of investment per increased pair of ducks.
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Thesis(M.Sc.)--University of Guelph, 1970.
Includes bibliographical references (leaves 73-76).
Internal-level ditches, dug by dragline in a shallow, densely- vegetated portion of Waterhen Marsh, Saskatchewan, increased use of the marsh by breeding pairs of ducks. The greatest ditch density, 416.3 m/ha,produced the greatest increase in pairs per unit area, 7.3 pairs/ha, but was least efficient in terms of investment per increased pair of ducks:$91.66/pair for the first year of development. The lowest ditch density,110.6 m/ha, produced the least increase in pairs per unit area, 2.9 to 4.2 pairs/ha, but was economically more efifcient than comparable,greater ditch densities: $60.76 to $42.10/pair for the first year.Ditches spaced 80 to 100 m apart were most efficient in terms of investment per increased pair of ducks.