Intertidal habitat mapping for ecosystem goods and services: Waikato estuaries

Waikato Regional Council contracted the National Institute of Water and Atmospheric Research (NIWA), to develop rapid assessment techniques for mapping of intertidal habitats associated with the provision of ecosystem goods and services.

The 2013 report documents the application and adaptation of the habitat mapping methodology for thirteen estuaries and harbours within the Waikato region: Otahu River, Whangamata Harbour, Wharekawa Harbour, Purangi River, Whitianga Harbour, Whangapoua Harbour, Kennedy Bay, Waikawau Bay, Port Charles, Colville Bay, Coromandel Harbour, Te Kouma Harbour and Manaia Harbour. The 2014 report documents the evolution of the methodology and a proof of concept using Tairua estuary as a test case to build a habitat map. The goal is to generate precursor maps that will facilitate the mapping of ecosystem goods and services in the near future. There were 12 habitats defined by characteristics/dominance of the fauna: cockles, pipi, cockles and pipi, Wedge shell (Macomona), oysters, crustacean burrows, crabs and cockles, tubeworms and cockles, snails (Amphibola), ‘low density deposit feeders’ (our baseline/LD deposit feeding community composition), ‘mounds and pits’ (similarly dominated by deposit feeders but featuring a distinct surface topography) and ‘low fauna’ (where macrofauna were extremely sparse).

Numerous estuaries on the Coromandel Peninsula

2013-2014

Field based observations of intertidal areas in each of the 13 study locations were undertaken to rapidly identify habitat characteristics linked to the provisioning of ecosystem goods and services. As much of the intertidal area in each estuary that could feasibly be covered given spring low tides was covered. Handheld global positioning systems (GPS) were used to demark boundaries between habitats, and geo-referenced photographs were collected inside each habitat type. All data were processed and converted into GIS map layers. Sediment information from each study location was also detailed for each habitat polygon using five broad categories (mud, sand, shell-hash, sandy mud/muddy sand mixture, and gravel mixture). Sediments were classified based on visual observations, textural analysis and sinking depth underfoot. Sediment samples were collected from each estuary for quantitative verification at a later date. There were three habitats defined by the characteristics/dominance of the flora: seagrass, mangroves and pneumatophores (the aerial roots of mangroves).

Report available as .pdf from Waikato Regional Council (see link below)

Report is freely available.