Inky feet, rolling rocks and seedy lizards at Mt Grand

Alpine geckoes, grand seed dispersers? Image from Andreas Widenmann.

 In late autumn, our postgrads in ECOL 609 Nature Conservation went on field trip to Central Otago where they conducted several days of research on lizards. Wilhelm and Andreas (both Master of International Nature Conservation students) tell us what they did.

Wilhelm Osterman : Do alpine geckos play a role in protecting native plant species?

The diverse alpine flora of New Zealand contains almost one third of the native species. Berries in various colors and tastes are found almost everywhere as you walk along hiking tracks on the south island. Plants have evolved their tasty pulp through selection by the animals feeding on them as a food resource to provide a way for plants to spread their seeds.

Which animals feed on these berries in New Zealand? With few native birds and declining gecko populations, lack of dispersal ability might pose a serious threat and allow invasive plants to take over. On a field trip to Mt.Grand, close to lake Hawea in Central Otago, I investigated if the Takitimu gecko (Mokopirirakau cryptozoicus) is an important seed disperser for some of the fruit-bearing shrubs.

A takitimu gecko. Image from Wilhelm Osterman.

I searched 90 suitable stones for hidden geckos, of which 14 had geckos underneath. We recorded the distances to shrubs with berries to all the stones turned. The geckos of New Zealand are good seed dispersers for shrubs, but different species of geckos may have different food preferences. It makes sense, considering the wide diversity of berries.

In our study 75% of the geckos were found close to the porcupine shrubs (Melictus alpinus).  Porcupine shrubs were only found in 27% of our plots. That the Takitimu gecko prefers to live close to this shrub indicates that it is an important source of food. Many of the alpine geckos of New Zealand have hardly been studied and are poorly understood. While a lot of focus is being put to study invasive species, these geckos may play an important part in preserving New Zealand’s native flora.

Andreas Wiedenmann : Get your hands dirty, please! Studying geckos and skinks with tracking tunnels at Mt Grand station, Otago

“We leave traces of ourselves wherever we go, on whatever we touch.” This quote is attributed to American physician and poet Lewis Thomas. It was very much what I wished geckos and skinks would do when I spent three days at Mt. Grand station near Wanaka for the ECOL609 field course. I hoped that they would be willing to get their hands dirty to reach the sweet temptation that lay in a puddle of black ink.

Gecko tracks: footprints and tailprints. Image from Andreas Widenmann

Together with Lincoln University researcher Mike Bowie, I set up five transects of tracking tunnels in different habitats at Mt Grand station. A tracking tunnel is a plastic tunnel with a cardboard inside which is painted with ink. To attract lizards, a piece of peach is placed in the middle of the cardboard. Any animal that is attracted by the bait will then leave its footprints on the cardboard. The transects where placed on a rocky ridge, a scree slope, a mountainside dominated by the fearsome points of the Speargrass Aciphylla, kanuka shrubland and a heavily grazed paddock.

Mike Bowie contemplates a tracking tunnel. Image from Andreas Widenmann

After one day the tracking tunnels were collected again. The first four cards were disappointingly white. The fifth finally showed what I wanted: tiny black fingers and a black streak indicating the tail – a skink couldn’t resist the yellow, fruity delight. Twenty-two of fifty cards showed signs of a visitor.

Most of the tracks could be attributed to skinks, some to geckos and, on five occasions, to hedgehogs. The analysis of the data will now show if there are significant differences between the habitats. However, one thing is for certain: the skinks and geckos of Mt Grand have left their tracks in my memories. The sunny three days I spent in their company were one of the highlights of my semester at Lincoln University.


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