Ecology of a coastal lagoon to dune forest sequence, south Westland, New Zealand

Abstract

The vegetation and floristic patterns in and around a coastal lagoon are described from quadrat sampling and related to several environmental factors (elevation, water depth, soil organic content, and pH). A cluster analysis was used to identify 14 communities while a detrended correspondence analysis ordinated the quadrats. The ordination's Axis 1 was correlated with water depth/elevation, while Axis 2 was correlated with soil organic content and, in the opposite direction, with soil pH.

Two vegetation development sequences are proposed for the dune hollow-ridge system: one in the hollows involving stages of aquatic, bog, and forest vegetation; the second on the ridges where forest composition changes in response to increasing soil development. Rates of succession arepresumably very slow.

Formal protection of the lagoon within the World Heritage area is justified because of its ecological, conservation, and scenic values; in light of diminishing natural wetlands; and the common occurrence of a vulnerable macrophyte, Myriophyllum robustum, in the lagoon.

Keywords:

• vegetation sequence
• vegetation analysis
• wetland
• dune forest
• ecological factors
• Haast Ecological District