Science Centres: Aquatic Biodiversity and Biosecurity

Predicted distributions of shortfin eels Anguilla australis in rivers and streams around Maungatautari in the Waikato region.

If you want to know where to find a banded kōkopu, or the biodiversity value of your local stream, we can help. Principal Scientist John Leathwick has predicted the likelihood of capturing the 30 commonest native freshwater fish just about anywhere in New Zealand.

Dr Leathwick developed statistical models linking fish distributions with environmental characteristics of streams and rivers for each of the 30 species. These drew on two large datasets developed by NIWA: the New Zealand Freshwater Fish Database, and the New Zealand River Environment Classification Database.

The models predict the probability of capturing each species in 570 000 river and stream segments throughout New Zealand, based on their known association with particular environmental attributes at 13 000 sample sites. “In other words, they use real data to predict the occurrence of fish in streams and rivers where we have no data,” says DrLeathwick.

“Results from this work have uses in a range of biodiversity management issues,” he says, “such as assessing the biological values of particular river and stream segments, setting restoration targets, and identifying sites to search for rare species.” We’re currently using the predictions to identify river catchments with high biodiversity values forEnvironment Waikato.

This work was funded by New Zealand’s Foundation for Research, Science and Technology, and the Terrestrial andFreshwater Biodiversity Information System Programme administered by the Department of Conservation.

A copy of the report, which includes predicted distribution maps for each species, is available at www.niwascience.co.nz/services/free/nzffd