Joy, M.K. & Death, R.G. (2004) Predictive modelling and spatial mapping of freshwater fish and decapod assemblages: an integrated GIS and neural network approach. Freshwater Biology, 49, 1036–1052.
We used stream fish and decapod spatial occurrence data extracted from the New Zealand Freshwater Fish Database combined with recent surveys and geospatial landuse data, geomorphologic, climatic, and spatial data in a geographical information system (GIS) to model fish occurrence in the Wellington Region, New Zealand. To predict the occurrence of each species at a site from a common set of predictor variables we used a multi- response, artificial neural network (ANN), to produce a single model to predict the entire fish and decapod assemblage in one procedure. The predictions from the ANN using this landscape scale data proved very accurate and four other evaluation metrics independent of species abundance or probability thresholds also confirmed the accuracy of the model. The geospatial data available for the entire regional river network were then used to create a habitat-suitability map for all 18 species over the regional river network using GIS. This prediction map has many potential uses including; monitoring and predicting temporal changes in fish communities caused by human activities and shifts in climate, identifying of areas in need of protection, biodiversity hotspots, and areas for the reintroduction of endangered or rare species.
02 March, 2005
Joy and Death (2004): Application of the Index of Biotic Integrity Methodology to New Zealand Freshwater Fish Communities.
Joy, M.K. & Death, R.G. (2004) Application of the Index of Biotic Integrity Methodology to New Zealand Freshwater Fish Communities. Environmental Management, 34, 415–428.
An index of biotic integrity (IBI) was developed for freshwater fish in New Zealand streams. Data on freshwater fish occurrence for 5007 sites over the entire country were obtained from the New Zealand freshwater fish database for the period 1980–2002. Corresponding environmental descriptors for the stream catchments above or at each of these sites were obtained from a number of databases using a geographic information system. Of the 12 original North American IBI metrics, only six were adapted and applied because of differences between the fish faunas of New Zealand and the United States of America. A number of evaluation methods showed all six metrics contributed to the overall IBI scores with high levels of consistency. The IBI assessment of sites sampled at different times showed high levels of temporal concordance. Overall, the results presented demonstrate the potential for New Zealand freshwater fish to be used to assess river condition at large spatial scales in New Zealand in the absence of specifically selected reference sites.
An index of biotic integrity (IBI) was developed for freshwater fish in New Zealand streams. Data on freshwater fish occurrence for 5007 sites over the entire country were obtained from the New Zealand freshwater fish database for the period 1980–2002. Corresponding environmental descriptors for the stream catchments above or at each of these sites were obtained from a number of databases using a geographic information system. Of the 12 original North American IBI metrics, only six were adapted and applied because of differences between the fish faunas of New Zealand and the United States of America. A number of evaluation methods showed all six metrics contributed to the overall IBI scores with high levels of consistency. The IBI assessment of sites sampled at different times showed high levels of temporal concordance. Overall, the results presented demonstrate the potential for New Zealand freshwater fish to be used to assess river condition at large spatial scales in New Zealand in the absence of specifically selected reference sites.
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