Chapter 22 - Inner shelf habitat surrounding the Kapiti Marine Reserve, New Zealand

Abstract

Identifying the geomorphology and biogenic habitats of an area are essential to understanding the processes influencing species’ distributions, ecological interactions, and managing the marine environment. We mapped the seafloor around Kapiti Marine Reserve, New Zealand, using a 30kHz multibeam echosounder, to produce highly detailed bathymetric and backscatter maps of the marine reserve and surrounding area. We used these data and morphometric derivatives to generate a 14-class Benthic Terrain Model (BTM). We combined the BTM with the backscatter facies to create 18 sampling zones; these were used to inform the spatial distribution of sampling for ground truthing and to define biogenic habitats. Ground truthing included 214 camera drops, 12 sled tows, and 46 dives. We present here the compilation of ground truthing and multibeam data to reveal the diversity of physical and biogenic habitats that comprise the submarine landscape surrounding Kapiti Island, which 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 macroinvertebrates and macroalgae. 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 and the biota it supports of the Kapiti Island region.