To help any species survive, it’s important that the population includes many individuals who are unrelated meaning there is a lot of genetic diversity. Genetic diversity plays a major role in a species adapting and evolving to survive environmental changes. If many individuals in a population are similar, they can all be affected by a threat in the same way and a large number of the population can be lost quickly. However, if many individuals have genetic differences, there is more chance that some will be resistant to a threat in some way and these might continue to breed resilient offspring.
By using established sperm collection and cryopreservation techniques to capture and store the genetics within these four frog breeding programs, this project aims to prevent loss of genetic diversity and perhaps even increase it via selective breeding to help save these species from extinction. Ultimately, the project will help to repopulate these four species in the wild to help them bounce back from the devastating 2019/20 bushfire season.
This biobanking project is already underway. Working with Taronga's awesome Herpetofauna division, reproductive biologists from Taronga Western Plains Zoo and the University of Wollongong spent time in the Taronga Institute labs testing different cryopreservation protocols with sperm from the endangered Booroolong frog (including adults that were rescued from bushfire-impacted regions of NSW last summer), and the critically endangered yellow-spotted bell frog.
Time is of the essence for this work as many males have not yet had the opportunity to reproduce naturally but are nearing the end of their natural lifespan. These 'founder' animals possess unique genes necessary for their species to adapt and survive in an ever-changing environment. By cryopreserving sperm, which can be stored for hundreds and even thousands of years, we can avoid the loss of this valuable genetic diversity, and in the long-term, positively impact the fitness of wild populations.
The work is ongoing but a sneak peak at some of the samples after thawing has shown some good looking swimmers! Excitingly, this is the first time that sperm from these species have been cryopreserved.
This work, with Taronga's partners at the University of Wollongong, University of Newcastle, Department of Planning, Industry and Environment and Zoos Victoria, is funded by a ZAA Wildlife Conservation Fund Grant as part of our Drought and Bushfire Wildlife Response.