FORAMINIFERAL ASSOCIATIONS IN THE UPPER WAITEMATA HARBOR, AUCKLAND, NEW-ZEALAND

Census data on 68 benthic foraminiferal tests in 56 seafloor sediment samples from the upper Waitemata Harbour, Auckland, New Zealand (36 de grees 50' S, 174 degrees 40' E) are analysed by Cluster Analysis. The faunal samples, taken from extreme high tide to 8 m depth, and from st rongly brackish to normal marine salinities, are grouped into 7 associ ations. Characterising species of each association are found by calcul ating Association Scores for each species, based on its mean abundance , relative abundance, fidelity, persistence, and dominance within each association. The foraminiferal associations are: JE, Jadammina macres cens-Elphidium excavatum f. clavata - high tidal, sandy mud, in salt m eadow and dwarf mangrove swamp, with near normal marine salinity; Tn, Trochammina inflata - around mean high water springs in salt marsh and salt meadow, with variable salinity; M, Miliammina fusca - subtidal c hannels and intertidal mud banks, mangrove swamp, and salt marsh with reduced salinity; H, Haplophragmoides wilberti - above mean high water , in salt meadow and salt marsh, with slightly reduced salinity; Tr, T rochamminita salsa intertidal sandy mud banks at head of estuary, with lowest salinity; AM, Ammonia beccarii-Miliammina fusca - intertidal a nd shallow subtidal mud flats and channels, with near normal marine to slightly reduced salinity; A, Ammonia beccarii - intertidal and subti dal (to 8 m+ depth) muddy sand, with near normal marine to slightly re duced salinity. In the cluster analysis dendrogram of samples, the fir st-order division produces a three-way split of (1) near-normal marine salinity agglutinated associations (JE,Tn); (2) low-salinity, aggluti nated associations (M,H,Tr); and (3) near-normal marine salinity, calc areous associations (AM,A). The dominant foraminiferal species are gro uped by cluster analysis into five species associations; these correla te closely with the sample associations. There is an overall trend of increasing species diversity from brackish to saline and from intertid al to subtidal. This study supports earlier conclusions that salinity and tidal exposure are the two most influential factors in determining foraminiferal distribution patterns in sheltered tidal harbours and e stuaries. A common species in the near-normal salinity subtidal channe ls, Siphogenerina striata, may have been introduced into the harbour w ith foreign shipping.