Rat Chat by Judy Gilbert  
When rare or new species come to light

Environmental News Issue 28 Winter 2011

One of the great things about having a dedicated field team working in the bush throughout the year is that unusual plants or animal species get noticed. The six member field team working in the 620 hectare Windy Hill Rosalie Bay Catchment Trust Sanctuary are all armed with cameras so that interesting views, aspects of their work, and species can be recorded at the time they are seen. Plant or fungi species are often brought into the field base for identification. These practices have created an enormous record of what is present within the Sanctuary and the frequency with which things are recorded also provides us with an idea of how species recover and become more visible when rat numbers are reduced.

Having many pairs of eyes on the ground has been how we found out we had an invasive water weed. A sample of the unusual species, probably brought in by ducks, was sent off to Ewen Cameron at the Auckland Museum and identified as the invasive Ludwigia palustris. The offending plant was then sprayed with an especially sourced organic spray and then the site monitored for a number of years. It has not returned.

A visiting herpetologist found the velvet worm (peripatus) on a recent visit. (See back cover article and photo.) This spectacular looking worm (when photographed closely) is a sign that the environment is in a pristine condition since it would not be present otherwise. This little critter has been around for about 500 million years - anatomically it represents a sort of half way stage between worms and arthropods (insects and crustacea). Some of the earlier fossil versions which lived in the sea were very weird - so much so that one specimen was called Halluciongenia! Velvet worms are found under rotting logs and in similar damp environments in the forests of the fragments of Gondwana (Australia, S. America and NZ).

Sometimes it takes a while for specimens to be examined. Invertebrate monitoring carried out by Auckland Museum at Windy Hill in 2001 has at last revealed a new species of worm – Aporodrilus aotea sp. nov. – it was identified by Robert Blakemore working on samples in Japan!

A young bird enthusiast recently visiting the sanctuary, identified a pair of bellbirds with a juvenile bird and found a pair of fernbirds which had been seen only once before.

The Sanctuary has a comprehensive monitoring program which has been in place since 2000. The data collected on rat densities, birds, weta, lizards, invertebrates, seedlings, and freshwater stream species allows us to measure how well our pest management is going and how much difference it is making. Monitoring for lizards using a range of traps has identified the rare striped skink and the chevron skink.

A Duvaucels gecko was caught in a rat trap in early 2010 – while its demise was sad – the specimen proved (with this second sighting ever in 40 years), that this species was still present, albeit in tiny numbers.

Photo by Craig McKenzie

Fungal Foray

The Windy Hill Rosalie Bay Sanctuary field team and interested locals recently joined Dr Maj Padamsee on a three day ‘fungal foray’ to find out what fungi are present in the sanctuary. Maj, who is a scientist with Landcare Research, and the team found 94 different species of fungi to add to the 40 already known to Landcare. A further six species were found on the way into the hot springs. The most spectacular fungi were found in the leaf litter under kauri trees on Benthorn Farm

Often, it is the day to day encounters that really give you a sense of the abundance of species that was once present on Great Barrier – the baby Pacific Gecko that has been born in my letterbox, the masses of cave weta that enjoy the warmth of my generator shed, the flocks of kaka, tui, and kereru that are present in the view from my home makes the grind of keeping rats at very low levels worth the effort.