Wildfires are natural and even beneficial. We are not talking about huge forest fires ignited by some people who were not careful at a campsite. Natural bushfires occur because of lightning and they clear out old dry grass, making space for new plants. It fertilizes the soil and signals various seeds to start growing. However, scientists from the University of Tasmania have now noticed that nature takes longer to recover from bushfires because of climate change.
Scientists analysed how natural soil chemicals respond to raising temperatures. Researchers studied karrikins – one of the most important group of chemicals, which stimulate the germination of seeds after bushfires. Interestingly, scientists found that karrikins only perform their functions when conditions are good and seeds can establish. For example, scientists took a look at thale cress (Arabidopsis thaliana) and noticed that if temperatures are too high and seeds don’t get enough water, karrikins actually inhibit their germination. This is extremely worrying – it means that after bushfires black fields will take longer to become green than usual.
Probably the worst part is that tolerances are very low. Even a few degrees above the optimum germination temperatures will inhibit the seed growth. Obviously, because of climate change we are expecting more frequent periods of extreme heat. That is when bushfires occur, but if it is going to be too hot, seeds are not going to get established and may even die out. Scientists now want to see if this effect can be noticed more broadly between fire-following species. If so, Australia is in for a trouble – in the future some fields can simply take too long to recover and remain black for too long.
Landscape regeneration is a natural process, but now it will be compromised by the climate change. High temperatures after bushfires may result in poor germination and, therefore, poor biological diversity. Professor Steven Smith, one of the authors of the study, said: “These findings argue for further research to determine the impact of this response of seeds to karrikins in natural environments and to find ways to better manage regeneration after fires”.
But what can we do to mitigate these problems? For now scientists do not have any good suggestions. However, in the future humans may have to actively promote biodiversity introducing seeds or combatting wildfires. In either way, nature will suffer from poor landscape regeneration process.
Source: University of Tasmania