In Australia between 2019 and 2020, huge tracts of forest and bushfires were destroyed, and these also affected habitats that normally do not need to fear fire. It follows from this that there is no protection for flora and fauna against such natural disasters.
These are temperate rainforests that extend from the eastern part of Gippsland in the state of Victoria to their areas south of Sydney. In general, these forests are moist enough to prevent large fires. However, the wildfires that broke out in the summer of 2019-2020 – a period also referred to as the Black Summer – destroyed 80,000 hectares of rainforest. the Phys.org New research cited estimates that more than 60 billion ground-level invertebrates, which play an important role in maintaining ecosystem balance, have also perished.
Although many are shocked by the sight of burning koalas and kangaroos, the destruction of the young is a silent tragedy.
The role of small creatures feeding on fallen leaves is multifaceted: on the one hand, they enrich the soil with nutrients, and on the other hand, they themselves provide a food source for mammals and birds in the Australian fauna. Most invertebrate species live in very small areas, so fires can cause a sharp decline in their numbers or even their extinction. However, since they are small and not “in sight”, we can easily underestimate their role in the ecosystem, and become aware of them only after an ecological disaster has occurred.
How do you know how many invertebrates have died?
In the warm and temperate rainforests, a variety of ancient life forms live in the humid Avars. Among them, you can find those that are clearly visible to the naked eye, such as ungulates, snails, millipedes, wasps, and beetles. Within these groups are countless species that are very small and therefore particularly dangerous from wildfires and other threats affecting their habitat.
To find out how many small creatures were lost there, a team of scientists collected 52 litter samples from both the fire-damaged temperate rainforest and the temperate rainforest in Australia one year after the fire. They then compared the results according to which areas were severely or moderately affected by wildfires, and which were avoided.
In the lab, a so-called Tullgren funnel was used to separate the scum from the animals that lived in it, and then the macroinvertebrates present were counted. Jumping forks and mites omitted because they are very common medium-sized invertebrates. According to the results
In intact rainforests, there are 2.5 million large invertebrates per hectare, while in areas severely affected by fire, there are only a quarter of that number.
If you look at all the forests affected by fires of varying intensity in southeastern Australia, that’s a small 60 billion deaths. However, only 1 percent of all wildfires have been associated with the rainforest, so the number of dead invertebrates could be close to 6 trillion. However, the truly astounding number emerges when we add in the number of jumping forks and mites, which make up nearly 95 percent of invertebrates:
So we can already talk about 120 trillion stillborn babies.
Why are these “invisible” beings so important?
Invertebrate species make up nearly 99 percent of the world’s animals and are the most abundant. It is currently estimated that 70 percent of invertebrate species in Australia alone are unknown to science. Many of them may be extinct before they are discovered.
Although we know very little about the ecology of individual species, we are generally aware that they perform critical functions for ecosystem functioning. The loss of this rich food source will slow the recovery of the populations of birds and mammals that eat it, such as ecosystem engineers like the stick-tailed and stick-tailed birds. These two species turn over the soil in large quantities when hunting these invertebrates.
It can also be difficult to plant trees to help regenerate forests: in the absence of many invertebrate species, plants grow with difficulty. Conservationists are trying to help with this by “transplanting” trees from healthy forests to those affected by the fire.
Small organisms living in the litter play a very important role in converting fallen leaves into usable nutrients for plants. Globally, these invertebrates convert 40 percent of garbage into soil-fertilizing organic matter. Without it, fallen leaves will accumulate, which will lead to more fires.
It follows from this that if we lose billions or trillions of invertebrates, the area affected by the disaster becomes more vulnerable to fires. Because of the more frequent fires, decomposition will be slower, so more dry debris will accumulate—that’s all the effect of not having the invertebrates previously destroyed by the fire.
Scientists also discovered that the truly destructive fires were those in which entire foliage was burned. Where half of the tree crowns remained intact, three to four times as many living organisms remained. And that’s good news, as invertebrate species seem to be fairly tolerant of fire, as long as at least some debris remains. So rescues must focus more on areas where the most foliage has died.
Frequent fires threaten rainforest species by encroaching on the surrounding eucalyptus trees. These are more resistant to fire, and since they drop a greater amount of leaves, they can start themselves.
One would think that the beetles could easily return if the rainforest regenerated. However, this does not always happen. Millipedes and wasps are present in great numbers in the avars, but they are unable to fly, and the scorched space between the two remaining patches of forest is an almost insurmountable obstacle for species accustomed to moist habitats.
What can we do?
A warming world will lead to more fires. In light of this, how can these indispensable invertebrates be protected? One way is to try to link their habitats where possible. The other is to revitalize disaster-stricken rainforests with debris from the untouched ones, thus helping to regenerate them.
Although it is possible to estimate the number of individuals killed by fire, we cannot know how many species died, as there are still many species unknown to science in these forests.
However, it is certain that we can no longer neglect the little things, because they are of vital importance to the functioning of ecosystems, and their absence is immediately felt.
