Ants reflect ecosystem restoration

CDU PhD student Allyson Malpartida uses a genetic approach to monitor ants at former Northern Territory mine sites to assess ecosystem health.

New research underway at Charles Darwin University (CDU) aims to develop a genetics-based technique to monitor ants and termites as indicators of ecosystem rehabilitation after mining.

CDU PhD student Allyson Malpartida uses a method called metabarcoding of DNA samples by capturing the genetic signature of each species at former Northern Territory mining sites to analyze ecosystem health, a first in the territory. .

In her research entitled “Developing a new genomic approach to use terrestrial invertebrates as bio-indicators”, Ms. Malpartida plans to develop a genomic approach to using invertebrates such as ants as indicators of mine site restoration.

She compares ant and termite communities of disturbed ecosystems in recovery with relatively intact ecosystems to measure ecosystem health.

“Healthy terrestrial invertebrates are important for a healthy ecosystem. Invertebrates like ants are very sensitive to changes in the environment, so they are good indicators of ecosystem health,” said Ms. Malpartida.

“Previously, many researchers avoided invertebrate sampling because the large number of potential species requiring specialized taxonomic expertise makes identification daunting.”

“We are testing some recently developed genetic methods to see if we can make this process less daunting and therefore ensure that invertebrate sampling is used more often in ecosystem rehabilitation.”

In addition to using DNA from ant and termite samples, Malpartida will also attempt to identify these insects from environmental DNA, known as eDNA, a less invasive method.

“For eDNA, we get our DNA samples from places like soil, or even termite bait, which contains traces of DNA left behind by insects moving through or on these substrates,” said she declared.

Through field trips and sample collections at the Ranger uranium mine in Kakadu National Park, she hopes to help develop a method for long-term monitoring of the mine to be integrated at the national park.

It is also taking samples from the Nabarlek uranium mine, Pine Creek gold mine and Jabiluka mine in the Northern Territory to analyze the recovery of these rehabilitated ecosystems.

With the data collected, Malpartida hopes to develop a reliable and cost-effective technique to assess how well the ecosystem at mine sites has been restored.

“My goal is to develop a method for long-term monitoring of terrestrial invertebrate bioindicators and make it more available for different companies and organizations to use the technology to assess land restoration,” she said.

“DNA sequence data can be stored and reanalyzed years later. As more species are added to reference databases, the analysis can be rerun and more can be retrieved over time, which is great for regulatory monitoring.

“Signs of returning invertebrates mean that some larger animals have a food source and may also return to a disturbed site. We need the invertebrates back before everything else comes back to earth.

The project is overseen by Professors Alan Andersen and Sam Banks of the CDU’s Environment and Livelihoods Research Institute and is in partnership with the Commonwealth Government through the Department’s Responsible Science Branch of Agriculture, Water and the Environment.

This research project has begun sampling at the site of the former Nabarlek uranium mine in western Arnhem Land and involves ongoing collaboration with the traditional owners of this site.

Allyson Malpartida’s project also involves collaborations with CSIRO Land and Water and the Center for Mined Land Rehabilitation at the University of Queensland.


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