Scientists are analysing the DNA of toads to establish if lockdown has allowed wildlife to travel further to mate.
Toads are susceptible to long-term effects from inbreeding when populations become isolated as they can often be hemmed in by roads. However, quieter roads during lockdown could mean safer, longer hops for frogs and toads introducing fresh blood to breeding ponds.
Now, scientists at NatureScot, the body responsible for Scotlandâs natural heritage, are to use DNA techniques to establish whether there has been an increase in genetic diversity among native amphibians.
The genetic testing can also help experts fill in the gaps of what was happening to wildlife in 2020. Restrictions on human activity meant less data was collected. But academics will be able to assess whether there were improvements in the genetic health of toad populations by taking swabs from their mouths or sampling the tail fins of tadpoles.
David OâBrien, NatureScotâs biodiversity evidence and reporting manager, said: âWhile we canât go back in time to see what happened last year, we will be able to get some idea from genetic data.
âWe suspect that some species have been able to move about more easily due to reduced road traffic. For example, toads suffer high mortality from vehicles, so roads act as barriers to movement and can lead to populations becoming isolated and inbred. Using genetic techniques, we will be able to see if animals were able to move between ponds. This increased movement may have long-term beneficial impacts on populations, particularly in urban areas.â
Inbreeding can cause birth defects, greater susceptibility to disease and behavioural abnormalities.
Frogs in urban areas have been found to be affected by inbreeding, though they are less prone to it than toads as they are happy to breed in any water they find. Toads return to the same breeding pond every spring when they migrate from the spot where they go to hibernate.
Male toads are more concerned with finding a mate than their destination pond, and their mating strategy involves hopping on the back of a female and accompanying her to her regular breeding site.
Experts say this can increase the genetic diversity within populations but many toads do not reach their chosen pond or lake as they often have to cross roads on the way and are run over. Roadkill is believed to be a significant factor in declining numbers of toads, as traffic has been shown to cause 30% drops in populations every 10 years. Scientists are hopeful that the lockdown during last yearâs breeding season in March and April will have meant more toads completed their journey and created a more diverse new generation.
Toads, frogs and newts will be DNA tested to assess the changes to their populations while human activity was curbed. A study carried out in Inverness has already shown that when frogs can travel freely using what is known as âgreen infrastructureâ rather than crossing roads, there is no evidence of inbreeding.
OâBrien added: âWe take DNA from amphibians using a little swab, which you put in their mouth. Obviously, you have to be very gentle.
âWeâve also taken DNA from the tail fins of tadpoles and from amphibian eggs, which means destroying the egg itself but given how few make it from egg to tadpole to adult frog [typically fewer than one in 1,000] this doesnât harm the population.â
Read more here:Â https://www.sundaypost.com/fp/amphibians-covid/
