Jamie Morton is the NZ Herald's science reporter.

Reconstructing 20,000 years of NZ history

Kea have had a long and colourful history in New Zealand's Southern Alps. Photo / File
Kea have had a long and colourful history in New Zealand's Southern Alps. Photo / File

Scientists will reconstruct more than 20,000 years of New Zealand's ecological history to better understand how our species will respond to climate change in the future.

A new $300,000 Marsden Fund study, led by Dr Nic Rawlence of Otago University, will draw on the latest DNA technology to create a new window into the country's recent geological past, revealing how bird and plant life adapted to massive shifts in climate.

Using a combination of well-preserved DNA from ancient species, carbon dating and isotope analysis, the study will particularly focus on what happened during and after the last "glacial maximum" in our history, around 21,000 years ago.

In this period, sprawling sheets of ice covered Northern Europe and large parts of North America and much of the planet was left cold, dry and inhospitable, with frequent storms and an atmosphere laden with dust.

Recent genetic studies have shown that, in frozen expanses of the Northern Hemisphere, large amounts of biodiversity was wiped out by the cold.

Yet, this impact wasn't seen everywhere.

Fresh data from mountain ranges in temperate regions, such as the Andes, Himalayas, Pyrenees and New Zealand's Southern Alps, actually indicates the opposite happened.

In fact, researchers now believe in some cases, glaciation can be a key force in structuring biodiversity along mountain chains by isolating populations, which in turn encourages new species to emerge.

"In temperate regions, what tends to happen is when there's glaciation in a place like the Southern Alps, rather than everything being eliminated from the entire region, you get these animal and plant refuges," Rawlence said.

The study will use fossil records of moa. Photo / File
The study will use fossil records of moa. Photo / File

In regions like northwest Nelson and Southland, species survived and evolved in pockets called "microrefugia".

"With this, we see all of this new diversity being created."

A recent study showed that, thanks to ice-age glaciers driving populations apart, there could be 11 distinct kiwi lineages.

Drawing on a database of genetic information, it examined kiwi across their geographic range and found a burst of diversity linked to repeated glaciations over the space of 800,000 years.

Read more: NZ project could transform bird conservation

Using DNA extracted from fossil bones, and organic material and pollen preserved in sediments, Rawlence and his team will investigate "real-time" changes in species' family history and geographic distribution.

The project will focus on iconic alpine bird species, including the moa, rock wren, and kea, as well as plant species like southern beech and rata in Southern Alps, following the last glacial period and through the holocene era, or the past 11,700 years of the planet's history.

Rock wren. Photo / File
Rock wren. Photo / File

Rawlence said New Zealand was fortunate to have an excellent fossil bone record, stretching back 60,000 years, along with another detailed geological record preserved in sediment and spanning back up to 150,000 years.

"This means we can directly track environmental change and evolution through time."
The study would be just as much about the future as it was about the past, because it would also reveal what happened during periods of warming.

"There's a famous phrase that the past is the key to the present and the future; to tell how species will respond to future climate change, we need to know how they responded in the past."

Why do inbred males fire blanks?

Another new DNA-based study will solve the mystery of why inbreeding in bird species leads to lower fertility and reduce health in offspring.

Otago University's Dr Helen Taylor will lead a world-first study on male inbreeding infertility in wild birds - something critical to national efforts to conserve cherished and threatened native species.

While infertility in birds has been studied before, only captive and laboratory populations of a single species were used.

In her study, Taylor will genetically assess blackbirds, South Island robins, dunnocks and hihi to pin-point general trends across and within species, including comparisons between the sperm of inbred versus outbred birds.

Her team will conduct computer-assisted sperm analysis and DNA fragmentation assessment to clarify the relationship between inbreeding and sperm quality, with an ultimate aim to reveal those genes that might be responsible for infertility in inbred males.

The research, supported by a new $300,000 Marsden Fund grant, seeks to boost efforts to manage threatened species and help improve captive breeding programmes, here and around the world.

- NZ Herald

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