New Zealand's Invasive Mammal Hitlist

 Welcome back!

I hope you have all had an amazing week. As you may or may not be aware there is a cold snap sweeping across the Uk and parts of Europe if that is you make sure to keep warm! Let's start this weeks post. 

They are responsible for a whopping NZ$3.3 billion loss in productivity each year and listed as one of the biggest threats to marine and terrestrial biodiversity. They are the Invasive Species. In light of the economic and ecological destruction caused by these invaders, James Russell and New Zealand are taking a stand. Desperate times are calling for some desperate measures. They have called for a mass eradication of all invasive mammals by the year of 2050 to preserve endemic wildlife. Is this extreme? Or, is this necessary?  

2015, marked the year where tourism became one of the most profitable industries above agriculture for New Zealand. This island boasts the last surviving species of Tuataras an order of reptiles that thrived in the age of the dinosaurs (top left). Not a reptile person? How about catching a glimpse of four species of Amphibians that are so ancient they have changed very little in the past 70 million years: the Pepeketua (bottom left). For those birdwatchers, the Island is known as the ‘seabird capital’ and home to the Kiwi! Truly a nature lovers paradise.

Invasive species pose a significant risk to this island’s biodiversity thereby posing a threat to their economy. In 2005 the IUCN found that over half of animal extinctions were caused by the presence of invasive species. New Zealand has already lost three of its endemic frog species due to the introduction of rats.  New Zealand aims to avoid further extinction by ordering an island-wide cull of invasive mammals. Take a look at the three invasive species that have earned the top three spots on New Zealand’s Hitlist!

The fight arrives in your own backyard… literally:

This extreme Conservation project will not be easy to carry out, the first issue arising is the sheer scale of this project.  Eradication projects such as this are not unheard of and actually boast high success rates but these have been on islands with an area of 128 square kilometres, New Zealand has a total area of 268,000 square kilometres.   

In addition to this, New Zealand’s dynamic landscape includes cities, forests and farms. Such differences in landscapes offer a multitude of safe havens for the top three on the island’s Hitlist. For this project to be successful, traps would have to be placed in people’s  back yards, as such the people of New Zealand must be behind this project 100% as anything less could lead to areas becoming refuges for invasive mammals. Turns out, the public is fully supportive of this mass cull. With support from the public, conservation groups and the government it seems the end of the line is near for New Zealand's Invasive mammals. Bad time to be a possum in New Zealand... or a rat... or a stoat.

Alright, so they have the support of the masses but how is the killing part going to carried out? After all, they are upscaling. The answer to that question is… they are not quite sure, there are a few methods in the pipeline such as:

Poisons: Always a good option when it comes to pest control. A common one being 1080 (sodium fluoroacetate) for killing rats. Drawbacks for this particular poison is that it also kills the endemic Kea bird.

Traps: Another familiar pest control method. Goodnature manufactures a trap that crushes the skulls of rats and possums. Clean up is free as the carcases are usually eaten by local cats… eww.

Not techy sounding enough? Well, how about using drones fitted with biosensors that ‘locate’ hot spots of invasive mammal activity and then drops poisons on the area? Still not impressive enough, well perhaps the use of genetic biocontrols will do.

Genetic biocontrols also referred to as Gene Drives are a really nifty bit of science. Using CRISPR-Cas9 scientists can introduce deleterious traits that will lead to suppressing the population of the invasive species. According to Ethan Bier a geneticist, once introduced the 'harmful trait can go from 1% to 100% in the span of just 10 generations'. Common targets for this approach are genes related to survival and reproduction.

Combating Invasive Species in the Future:

Invasive Species have infiltrated many continents and this is facilitated by the increase in globalisation and environmental changes. Rapidly changing climates allow for species to succeed and become established in areas they would normally perish in.

Britain has been invaded by a variety of species whether they are introduced accidentally or deliberately (as a biological control for some other pest). BBC has shortlisted the UK’s most invasive animals featuring the Himalayan Balsam that costs the UK economy £150 million a year, the American Mink originally brought over for the fur trade has now been implicated in the dramatic declines of water voles. The list continues.

New Zealand’s public has rallied in support of preserving their island's wildlife, and even though they are somewhat resistant to genetic biocontrols they are more than willing to kill in the name of conservation. With British Invaders wreaking havoc on our economies and nature it begs the question: Are we willing to kill to save our wildlife?

That is all, for now, guys! Thanks so much for reading and have an awesome weekend. 

Science in the City

Brian Owens. The Big Cull. Nature. 451, 7636 (2017).
Regan Early, Bethany A. Bradley, Jeffrey S. Dukes, Joshua J. Lawler, Julian D. Olden, Dana M. Blumenthal, Patrick Gonzalez, Edwin D. Grosholz, Ines Ibañez, Luke P. Miller, Cascade J. B. Sorte & Andrew J. Tatem. Global Threats from invasive alien species in the 21st Century and national response capacities. Nature. 7 (2016).

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