Linking Physical and Biogenic Habitats to Reveal Kapiti Island’s Submarine Landscape

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Entry for:
Image1466139974?1466139974  NZMSS Student Awards





1. Abstract

Kapiti Island is one of the country's iconic natural places encircled by one of New Zealand’s oldest marine reserves, which is classed as a “Coastal Gem”.  Surprisingly knowledge of the seafloor morphology around Kapiti Island dates from the 1990s and has a low level of detail. Identifying the geomorphology and biogenic habitats of an area are essential to understanding the patterns and processes influencing species’ distributions, ecological interactions and managing the marine environment.  Through a collaborative mapping initiative, NIWA mapped the seafloor using a Kongsberg EM2040 Multibeam Echosounder (MBES) to produce highly detailed maps of the reserve and surrounding area. Preliminary bathymetry data was visually analysed and segmented into 18 habitat types to target for validation of the multibeam and further define biogenic habitats.  Visual assessment included 214 camera drops, 12 sled tows, 46 dives to provide comprehensive ground-truthing. We present here the compilation of visual assessment and multi-beam data to reveal the diversity of physical and biogenic habitats that comprise the submarine landscape surrounding Kapiti Island. Habitat types include: soft sediments with associated infaunal communities, large areas of rock rubble and gravels with mobile invertebrates, extensive anemone and rhodolith beds, boulder fields with dense macroalgal stands, flat and complex rocky reefs encrusted with a diversity of invertebrates and algae. This multidisciplinary and scalar approach supports a greater ability to effectively manage the area and promote awareness of the richness, diversity and complexity of the seafloor of the Kapiti Island region and the biota it supports. 



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