It’s hard not to be horror-stricken by the devastating Australian fire season of 2019-20. Over seven months, more than 17 million hectares of land were scorched by brutal fires, an area two-thirds the size of the UK. Some areas were hit harder than others, including Kangaroo Island in South Australia, where more than half the island was destroyed by fires. Nationwide, the fires killed 33 people and destroyed over 3,000 homes. The fires also had a catastrophic impact on Australian wildlife.
While it’s normal for Australia to have a fire season over summer, what isn’t ‘normal’ is the steady drop in rainfall and rising temperatures we have seen across mainland Australia in recent decades, which undoubtedly contributed to this truly destructive fire season.
In February, the Australian Government announced that 113 threatened animal species had at least 30% of their known distribution in the heart of fire-stricken regions. The government also reported that 29 out of 30 threatened plant species had more than 80% of their habitat lost and several species may have gone completely extinct.
How science can help
An important aspect of effective conservation is adaptability and being able to move with the times. Thankfully, conservation is enjoying another transformation – by joining forces with science. When we think of science, many people think back to their high school days in lab coats and goggles hovering over Bunsen burners.
Fortunately, science can be a lot more exciting and useful than our memories of biology class. Although field work is the most obvious go-to option for a lot of conservationists, there are some issues that can’t be solved in the field. This is when we must don the lab coat once again and explore more drastic options.
One of those options is assisted reproductive technologies (ARTs). The most common ARTs in our arsenal are sperm cryopreservation (keeping sperm at very low temperatures to preserve it without damage) and artificial insemination (AI), in which sperm is taken from the male and injected into the female. These techniques are often used very successfully together. ARTs have been used in some species for over 20 years and have been used successfully to enhance breeding efficiency, overcome fertility issues and limit inbreeding.
Although common, ARTs require an immense understanding of animal reproductive biology. Several institutes around Australia are working hard on improving our understanding of animal reproduction and, as a result, a new direction for conservation has emerged: the idea of a ‘frozen zoo’.
A frozen zoo stores cells from animal or plant species in liquid nitrogen at an incredible -196°C. The cells are still alive at this temperature, but are dormant. Once warmed back up, these cells can be used in breeding programs to produce healthy offspring.
Several frozen zoos exist in Australia including the Australian Frozen Zoo, the Taronga Cryodiversity Bank and the Australian Plantbank. ‘Cryoconservation’ is a rapidly growing field worldwide and ARTs have been successfully applied in conservation efforts for a variety of taxa including Magellanic Penguins, Southern White Rhinos, Yellow-spotted Monitors and, everybody’s favourite, koalas.
Koalas and ARTs
Considering that roughly a third of the koala population in New South Wales may have perished during this fire season, frozen zoos could be a powerful tool for the preservation of one of Australia’s most iconic animal species. Over the past 30 years, koala AI has become so successful that the birth rates are only slightly less than that of natural matings. In fact, in 2014, the Queensland State Government recognised its application in koala conservation and AI was incorporated into the species management policy – a big win for conservationists and scientists alike.
Unfortunately, koala sperm is quite tricky to freeze, which makes it very difficult to ship nationally or internationally for breeding. However, in late 2019, Dr Bridie Schultz of the University of Queensland showed that koala sperm may be chilled at 5°C for over 40 days. This discovery opened the door for a very ambitious, nationwide breeding effort with potentially profound implications for koala populations.
When animal populations become fragmented, as has happened with koalas in the most recent fire season, there is limited gene-flow between populations. This means there isn’t enough genetic diversity in the remaining populations and the animals become ‘less fit’ for survival. By having a reliable method for transporting koala sperm, we’re now able to manage koala genetics much more effectively. It’s now a matter of time, planning and, unfortunately, money.
Looking to the future
ARTs are by no means the only solution to the larger problem. However, frozen zoos provide us with a ‘Noah’s Ark’ of the world’s threatened species, and, combined with techniques like AI, can help manage declining or fragmented populations more effectively.
Together with field work and reintroduction programs, ARTs can reliably assist in a lot of conservation efforts, especially where traditional breeding efforts are failing.
There is a catch, though: it’s all well and good helping to breed more endangered animals, but if we reintroduce a species back into the same environment which led to their demise, is that effective conservation? Reducing the impact of climate change, although daunting, is a global effort and may be the only option to truly conserve the world’s flora and fauna. Having said that, if we lose the race against species extinction, we will be glad we invested in ARTs and frozen zoos while we still had time.