Two Birds, One Stone

By Matthew Wood 15/04/2010


P1110243Each year the School of Biological Sciences and the School of Geography, Environment and Earth Sciences at Victoria University of Wellington join forces to take 2nd year science students to Lake Rotoiti in Nelson Lakes National Park. The Environmental Studies/Biology 222 paper combines the two complementary disciplines in a single field trip.

The course takes a holistic approach to explaining the environment of the area, exploring the intricate interconnections between geology, geomorphology, and the floral and faunal assemblages. At one moment students are shown the control of vegetation by geology — the alkaline soils derived from the ultramafic ophiolite rocks of the Red Hills provide sustenance for only a thin cover of the most undemanding scrub — the next, how forest cover (or the lack of it) can alter natural denudation rates by orders of magnitude. Fire ravaged the forest cover on the north face of Mt. Robert in the early 20th century, leading to ever-deepening scree-filled gullies and the reactivation of dormant colluvial fans.

The landscape of Lake Rotoiti has largely been hewn from the geological basement by glaciers, which have advanced periodically throughout the Quaternary. Today the ice is long gone, but its legacy is written in landforms; a moraine here, a truncated spur or two there. The barren mountain slopes left behind  by retreating ice at the end of the last glaciation have been transformed into stratified soils by untold generations of beech forest. Choruses of tui and bellbirds fill the canopy at lower elevation while weka and New Zealand robins forage for terrestrial invertebrates across the forest floor below.

The major assessment for the course requires the students to propose and execute a field study in the area using the scientific tools they have been equipped with earlier in the week: soil sampling and description, bird call, insect and tree species identification and landform sketching. The second week is coming to an end and the group projects are looking good! Hopefully students from each academic camp will go home appreciating that when it comes to understanding our natural environment, the perspectives of geologists and biologists are by no means mutually exclusive.

Photos (c) Matthew Wood 2010

Pano Rotoiti Crop