Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search

 

Rats just kept on coming

Image available

Introduced rats have thrived since being introduced into New Zealand but a new study shows they not only spread rapidly through population growth, new arrivals kept jumping ship well into the 20th Century.

Using population genetics to trace the genealogical lineage of rats, a team of scientists at the University of Auckland has tracked the spread of the two commonest rat species across the entire country for the first time.

“Thanks to a huge sampling effort from community groups trapping all around New Zealand, we were able to sample over 500 rats to connect the dots for how rats invaded,” says Associate Professor of Statistics at the University of Auckland Rachel Fewster who runs the national rat trap monitoring software CatchIT.

The results showed widespread genetic diversity for the commonest rat species, R. rattus, or ship rat, suggesting at least four different invasions in both the North and South Island and on offshore islands like Great Barrier Island and Stewart Island. Each new invasion was trackable through new genes being introduced into the gene pool each time.

The study found the less common but still widespread R. norvegicus, or Norway rat, had more limited diversity within its gene pool, with two main invasions across New Zealand – one on the North Island and some offshore islands, and the other on the South Island, potentially with both English and Chinese origins.

“The genetics show how quickly rats would have overrun New Zealand when they arrived, and eaten their way through our bird and reptile populations,” says Associate Professor James Russell, who led the study.



“Using these results, today we can trace new arrivals of rats across New Zealand which will be critical if we are serious about reaching our goal of being predator-free by 2050.”

As both common rat species quickly established and rapidly spread by the 19th Century, they displaced R. exulans – kiore or Pacific rat – introduced by Polynesian settlers in the late 13th Century. Eventually the kiore rat became restricted to remote parts of both main islands and a few offshore islands.

The paper is published in Frontiers in Ecology and Evolution and is available open access for download at https://www.frontiersin.org/articles/10.3389/fevo.2019.00048/


ends

© Scoop Media

 
 
 
Business Headlines | Sci-Tech Headlines

 

Tax Bill Passes, Drops: “An End To Unnecessary Secondary Tax”

“The changes mean Inland Revenue will more closely monitor the tax paid by wage and salary earners through the year. If it appears the worker is being over taxed, Inland Revenue will suggest a more suitable PAYE tax code tailored to that worker.” More>>

ALSO:

Ethiopian Airline Crash: Boeing 737 Max Aircraft Operations Temporarily Suspended

New Zealand’s Civil Aviation Authority has suspended the operation of Boeing 737 MAX aircraft to or from New Zealand. Currently this affects only one operator, Fiji Airways. There are no other airlines that fly this aircraft type to New Zealand. More>>

ALSO:

Sorting Out DNA: Crime-Busting Software Wins Top Science Prize

Software developed in New Zealand that has contributed to identifying suspects in tens of thousands of criminal cases around the world has won the 2018 Prime Minister’s $500,000 Science Prize. More>>

ALSO:

In The High Court: IRD Wins Tax Avoidance Case

Inland Revenue has won a High Court case against Eric Watson’s Cullen Group over a nearly $52 million tax debt. More>>

ALSO:

Insurers Withdraw From Market: Plea For EQC Rethink

A consumer watchdog wants the government to rethink the Earthquake Commission (EQC) as more people are pushed out of getting property and contents insurance. More>>

ALSO:

Women's Day: New Zealand Rated Third Best In OECD For Working Women

New Zealand has been rated among the top countries in the world for working women. The Women in Work Index rated New Zealand third in the OECD and it was the only country outside Europe to make the top 10. More>>

ALSO: