Geoscientist discusses country’s mountains
Internationally renowned geoscientist Dave Craw will visit Wairarapa next week to explain a novel link between mountain building and genetics.
Over the past ten years Craw and his University of Otago colleagues have tackled the question of how New Zealand’s mountainous topography developed by integrating research in the very different fields of geology and molecular studies of freshwater fish.
The work is bringing new understanding of how landscape change—especially mountain building—influences genetics, evolution and biodiversity.
‘‘The mountainous New Zealand landscape spectacularly reflects the activity along the Pacific-Australian plate boundary,’’ Craw said.
‘‘As a geologist, all I have to go on is what I see today, because earlier versions of the topography have been eroded away.’’
He said some native freshwater fish carry in their DNA a biological memory of the topographic environments in which they evolved.
‘‘In particular, changes in river drainage patterns have isolated species and populations of the genus Galaxias that are limited to fresh water.
‘‘This allows us to use the genetic signature from fish in different catchments to unravel the history of landscape uplift and erosion. The result is increasing biological diversity and co-evolution of topography and fish.’’
This is nowhere better seen than in the South Island, where the Otago scientists use genetic variations in fish to document the nature and timing of river captures and mountain range growth, sometimes as far back as five million years.
‘‘We’re gaining new insights into how the New Zealand landmass has developed since it was submerged—or nearly submerged—in Oligocene time,’’ he said.
‘‘We could extend the same ‘biological memory’ approach to all native plants and animals whose distribution we know and for which we can find genetic data.’’
Craw’s talk, Tectonics and genetics in topographic evolution is the Geoscience Society of New Zealand’s Hochstetter Lecture for 2017. He will deliver it to a meeting of Science Wairarapa at 7.30 pm on September 13 at the Education Centre, 22 Dixon St. Masterton. A small door charge will apply.
Geoscientist Dave Craw, who will deliver a lecture on topography in Masterton.