Why are some areas in the world more biodiverse than others?

You often hear that it is very important to preserve Earth’s biodiversity. However, it is not very uniform as it is. There are some serious hotspots, such as Daintree Rainforest in Australia and the Cloud Forests of Ecuador. But why do these extremely biodiverse islands form? Scientists from the University of York, Nelson Mandela University and the University of Cape Town think they found the answer.

Daintree Rainforest in Queensland, Australia, has thousands of different species of plants. Image credit: Robert Linsdell via Wikimedia (CC BY 2.0)

There are several serious biodiversity hotspots in the world. If you look at them closely, you will soon realize that all of them have something in common – they are all in tropical or at least positively hot regions. It is obvious that arctic regions where conditions are harsh biodiversity is unlikely. However, rainforests in particular are just thriving with life, even though they are not the only areas in the world with positively good conditions.

An international team of scientists focused on the Cape Floristic Region in South Africa, which is a non-tropical heartland of biodiversity. They mapped the distributions of nearly all of the region’s 9400 plant species and found that the reason why this place has such a biodiversity of life might be related to the climate. This new study showed that the climate in the are didn’t change much over the past 140,000 years. These findings allow looking to biodiversity a bit differently and also emphasize the risks of the ongoing climate change.

Previously it was assumed that  large amounts of energy flowing through an ecosystem make it biodiverse. Scientists can confirm this factor to be true, but also note that it plays only a minor role. It is environmental stability that happens to be more important for biodiversity, because unchanged conditions allowed the evolution to go ahead undisturbed. In other words, nature took its course without major shocks. And it is quite surprising that productivity, defined as a big flow of energy in an ecosystem, is simply not needed for a hugely biologically diverse area to form.

Dr Richard Cowling, senior author of the study, said: “Our study shows that the environmental stability of south-western South Africa, in conjunction with the region’s rugged topography, explains diversity gradients in the region. The same hypotheses can explain tropical diversity; there is no need to invoke productivity”.

More than anything this study shows that we need quick action against climate change. These hotspot of biodiversity were formed through thousands of years of relatively stable climate. This means that they are likely to be the most vulnerable to a sudden change. We have to find quick ways to protect them, because they will be the ones to die first.


Source: University of York

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