Environmental controls on benthic foraminiferal and thecamoebian associations in a New Zealand tidal inlet

Census data on benthic foraminiferal and thecamoe-bian tests in 52 surface sediment samples from Pnrak-anui Inlet, Otago, New Zealand, are analyzed by cluster and correspondence analyses. Faunas are grouped into 10 sample associations with the following characterizing species: A) Trochamrnina inJlnta-at or above mean high water level in high salt meadow, salt marsh or grass; B) Jadamrnina mocrescensiTrochammina infita-at or above mean high-water level on the edge of high salt meadow; C) Trochamminita salsa-in sandy soil at around mean high-water spring, possibly inlinenced by fresh groundwater seepage; D) Pontigulasia compressal Trochamminita salsalDi&gia capreolata-at high tide level in the bed of the main freshwater stream flowing into the inlet; E) Haplophragmoides wilberh-in salt marsh and grass at mean high-water level on the edge of the inlet; F) Miliammimfusca-in Sarcocornia mnd-dy, low salt meadow and sandy mud flats between mid and high tide levels; G) Elphidium excavahrmdver a wide area of tidal sand flats in the upper and middle parts of the inlet; €I) Ammonia beccariilElphidium ex-cavatum-in three areas of tidal sand Aat in association with G, but with slightly lower salinity and nutrients; I) Elphidium excavahrmiHaynesina depressula-intertid-ally and subtidally around the inner end of the entrance channel in the vicinity of the flood tide sand delta, J) Zeafrorilns parri-intertidally and subtidally in the shal-low, current swept entrance to the inlet. These correlate closely with the 8 species associations produced by clus-ter analysis. Canonical Correspondence analysis indicates that the following factors in decreasing order of importance are most influential in determining the faunal distribution: tidal exposure, salinity, percentage of mud, proximity of the open sea, organic carbon, phosphate and intertidal vegetation type.