A VEGETATION ZONATION FROM SALT-MARSH TO RIVERBANK IN NEW-ZEALAND

Abstract. Brackish riverbank marshes have been little studied. Therefore, a plant community sequence was sampled from saltmarsh to near‐freshwater riverbank marsh on a number of disjunct marshes along the Taieri River, Otago, New Zealand, from near the mouth to 9 km inland. Salinity decreased steadily upstream, though the actual values were very different on two days sampled. Ten communities are recognised. The major vegetation zonation was upshore more than upstream, though there were several interactions between the upshore and upstream gradients. Few species, if any, were restricted to the mid reaches of the length of river sampled. There was only a very slight upshore increase in species richness, and no trend upstream. Sequences of communities occurred upshore on all marshes, but the sequence differed, even within a marsh. Species were assorted into communities in different ways from those of marine marshes in the area. Some species, native and exotic, occupied different beta‐niches from those they occupied in other countries. Individualistic community structure is inferred. 1990 IAVS ‐ the International Association of Vegetation Science