The reason why the loss of biodiversity and the spike in viruses is and has been occurring for the last few decades is simply due to increased contact with wildlife in many areas around the world. With fewer habitats every year due to deforestation, means more wildlife will have to try and live in urban cities or become more prone to come into contact with human civilization since their homes were cut down.
In turn, That increases the chances of viral infections between plants, animals, and humans. Especially that a lot of the plants and animals that survive deforestation and loss of biodiversity are more likely to carry lots of pathogens and viruses with them that don’t affect them, and act as a transmission vector. Once these viruses are transferred to humans, they can have different and adverse effects on us.
In fact, the covid-19 pandemic can be and have been blamed on the wildlife trade center of China, since that’s where the first covid infections have appeared in early 2019. Due to increased contact with wildlife, livestock, and animals in general. More infections seem to be appearing worldwide, that includes Ebola, SARS, and the bird influenza. That spike has been seen in just the last few decades, which many ecologists warned us from in the late 20th century but no one listened.
Another reason (although not as related to biodiversity) as to why more viruses are prone to keep appearing in the 21st century is due to the melting ice caps. It is believed that there are ancient bacteria and viruses that are frozen in the arctic dating back to early Earth and they are now being exposed again to the world due to climate change and increasing temperatures.
References:
Tollefson, J. (2020, August 7). Why deforestation and extinctions make pandemics more likely. Nature News. Retrieved March 5, 2022, from https://www.nature.com/articles/d41586-020-02341-1
Applied Plant Ecology Winter 2020 