Monitoring Protocol for NZ Estuaries – Whangamata Harbour

Whangamata Harbour was chosen as one of the eight study estuaries to trial baseline assessment and monitoring of estuarine habitat. Estuarine vegetation and sediment types are mapped. Purpose: The primary aim of the study is to develop and undertake baseline monitoring of a suite of benthic characteristics as potential indicators of estuarine environmental health. The estuary monitoring protocol is simply a standard method or approach to assess the current state or condition of a particular estuary in order to establish a benchmark for comparison with subsequent surveys. A major advantage of using a standard approach is that it generates an integrated database that not only facilitates comparisons with successive monitoring surveys, but also allows interpretation with respect to other estuaries/regions.The EMP was intended to provide environmental resource managers with a set of tools to assess and monitor the status of estuaries in their region. To achieve this, the protocol was required to be scientifically defensible, cost-effective, practical/easy to use, and applicable to estuaries throughout New Zealand.

GIS layer of vegetation and sediment types in Whangamata Harbour. Study design and reasons for decisions for broad and fine-scale assessment of habitat is provided in Robertson et al. 2000.

Whangamata Harbour

Whangamata Harbour – E2764538 N6442493, NZMG, 1:20000, AREA

2000-2001

Broad-scale: Field surveys determining species composition and boundaries on aerial maps. The project contained three integral components: Frequency of collection: Suggested to be repeated every 5 years.

The categorisation of estuary condition seems to require personal judgement. Some vegetation such as seameadow species often do not show up on aerial maps and could potentially be left out - i.e. Macro communities sampled rather than 'key' communities.

report, maps Digital Format: MS Word, GIS (ArcView)

Contact Ministry for the Environment Sensitivity/Confidentiality: Contact Ministry for the Environment

Complete? Or to be resurveyed?

Simple, defensible and cost-effective strategies are required to assess and monitor estuary condition, and also predict the results of management actions. The first stage of this study aims to provide: A robust GIS based methodology for mapping the spatial distribution of estuary habitat and a series of habitat maps prepared by trialling the approach on 8 NZ estuaries. An initial categorization of estuary condition (e.g. pristine, slightly modified, modified, and highly modified) using the habitat map and existing, easily-obtainable, land use and estuary data. Testing this categorization on selected estuaries by measuring the spatial variation (within estuaries and between estuaries) and interrelationships of a suite of commonly measured benthic indicators in one typical soft sediment estuarine habitat. A defensible optimized sampling design and methodology for assessment and monitoring of the soft sediment benthic habitat. Evidence to support the use of particular indicators in appropriate circumstances. (Robertson et al. 2000) Additional comments: The grass recorded as Paspalum distichum is more likely to be the salt tolerant P. vaginatum (M.Graeme, pers com).