Has a new mass extinction of life on earth already started? After all, it has already happened five times! To answer the question we need to step back and recap some of the earth’s history as related to life.
The first traces of complex life appeared about 600 millions years ago. I think life is much older than that, but that was the first time that there were sufficient skeletons left that could be preserved as fossils. Life forms then exploded and the first mass extinction occurred about 450 million years ago, where more than 80% of species were wiped out. The most devastating extinction occurred about 250 million years ago when 95 % of life was wiped out. The most recent one was 65 millions years ago and was caused by the impact of a massive meteorite that landed in the sea near Mexico. That was also the end of the Dinosaurs. Over the last 65 million years, life adapted to the new environment and climate. (It must be kept in mind that an extinction event is not instantaneous and probably lasts a few hundred thousand years or even longer).
Has the next extinction already started? Everything around us looks so “normal”. I assure you it is not normal. According to the WWF report “Living Planet Report 2018”, 60% of life (not only plants) has gone extinct since 1970. The reason is that we have altered the composition of the atmosphere to such an extent that climate change is already taking place. Energy from the sun that was captured in the form of coal over millions of years are suddenly released back into the atmosphere in a hundred odd years. We are upsetting an ecology that developed over 65 million years in just a hundred years and then we think it is business as usual?
What exacerbates the situation is the uncontrolled spread of alien invasive plants. This point was forcefully emphasized in the Southern Cape with the extensive fires that is devastating to the area. There are two reasons. Natural vegetation needs to be burnt from time to time to avoid excess of biomass – that is part of their survival strategy. Fire is an essential part of that ecology, but, these fires are normally fairly cool and resprouting of burnt plants and seed germination follows soon afterwards. Unfortunately, this does not happen as often as it should and that resulted in an excess of biomass fueling the fires.
The dense stands of invasive plants led to extremely hot fires that killed off virtually all indigenous plants in close proximity and also destroyed the seed bank in the soil. These extremely hot fires also spewed ‘fireballs’ into the air, which can start new fires kilometers away, exacerbating difficulties with controlling these fires. Where the vegetation was close to original, long-term damage by fire was minimal.
One amazing action that took place during the recent events in the Southern Cape was the fact that Gift of the Givers saved more than 2 million bees from certain death. That is what I call a long-term vision, because if the bees go, so do we.
So what can we do? I am afraid not much with a long-term impact. One international action aimed at preserving some plants from extinction was the establishment of a seed bank (now known as the Millennium Seed Bank Project) where seeds are stored at very low temperatures. In June 2018, 39 100 species and 2,25 billion seeds were in storage in 189 countries. To put that in perspective – in South Africa (not SADC) alone we have ~ 23 000 plant species. There is still a long road ahead.
Locally we can create a habitat in our own environment (whether a garden, a park or an estate) that will support wildlife and biodiversity. In addition, we can really become more involved in the removal of unwanted alien species that smother our indigenous flora (just for the record – not all exotic species are invasive).
This will only happen if we completely revise our concept of a “garden”. Our concept still dates from Victorian times when weird and wonderful plants were collected worldwide for display, especially in Europe. The emphasis was on big, colourful flowers. Today that has turned into a multi-billion Dollar industry with scant attention to the role of ecology. We should move back to our roots in Africa where ecology should be the driving force. Plants should not exist in isolation – they should be the skeletons that support other forms of life.