Distribution and ecological characteristics of Zannichellia palustris L. along the Alaska Pacific coast

Zanichellia palustris L. is found in many locations along the Alaska Pacific coast from Cook Inlet to Juneau in ponds and on bare mud where the influence of fresh water is significant. It is often an associate of Potamogeton supp., Myriophyllum spicatum, and Hippurus tetraphylla. Successionally, Z. palustris decreases markedly as Carex lyngbyei increases and it is very sensitive to a substrate of Carex peat; also it appears to be sensitive to sedimentation and showed dramatic decreases in the vicinity of construction at Port Valdez from 1970-1974. This species is suggested for inclusion in baseline ecological studies because of its rapid response to environmental change.