Geo­sci­en­tist dis­cusses coun­try’s moun­tains

Wairarapa News - - WHAT’S ON - JOHN RHODES

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.

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