The effect of above-normal flooding of a northern prairie marsh on Agraylea multipunctata Curtis (Trichoptera: Hydroptildae) / Lisette C.M. Ross and Henry R. Murkin.

Includes bibliographical references (pages 33-35).

This study examined the emergence response of Agray/ea mu/tipunctata to
both normal and above-normal flooding in a series of experimental marshes in the
Delta Marsh, Manitoba. Marshes were flooded 1 m above the existing cattail beds
for up to two years. During periods of normal water depths, A. multipunctata
densities were low in all cover types except open water. Open water sites showed
an early, high emergence period in late May I early June followed by low
emergence during midsummer and a second high emergence period beginning in
mid-August. The remaining four cover types did not show distinctive emergence
patterns. Annual emergence increased significantly in all cover types during the
first year of flooding. Cover types displayed three emergence peaks in late May
I early June, mid-July, and late August to late September. The highest annual
emergence in each cover type occurred during the second year of flooding with
hardstem bulrush sites being the most productive. Increases in A. multipunctata
are likely due to increases in water depths, metaphytic algae, illumination and
submerged vegetation during the above-normal flooding period.