What Is Biodiversity?

Anyone with a functioning sense of biophilia is familiar with the concept of biodiversity. It is the very substance of conservation biology; you cannot discuss one without discussing the other. Attempting to do so would be a bit like a biography of Bruce Springsteen failing to mention New Jersey. Yes, we have all heard the word, but it is often helpful to ensure that we are defining our terms correctly. 

So, then, what does the word biodiversity actually mean?

Generally speaking, it seems that many people define biodiversity in a rather wiggly fashion, something along the lines of “a bunch of natural stuff interacting with other natural stuff.” That’s close, but the concept is a good deal more complex.

According to the book An Introduction to Conservation Biology, biodiversity is defined this way:

[Biodiversity is] the complete range of species and biological communities on earth, as well as the genetic variation within those species and all ecosystem processes.

Broken down a little further, there are three main subcategories the authors mark for consideration.

1. Species diversity: This includes every species on earth, from bacteria to blue whales, as well as plants and fungi. It is not, as is sometimes mistakenly assumed, concerned with only endangered species, although endangered species are precise indicators of failing biodiversity.

 

2. Genetic diversity: Here we are talking about the genetic variation within species, whether in the same population or in geographically separate populations.

 

3. Ecosystem diversity: The trickiest of the three to define, it includes every biological community in nature, as well as how each community associates with the chemical and physical elements that make up an individual ecosystem. This includes natural ecosystems as well as those that are managed by humans.

In order for life on this planet to survive all three of the above levels must be dynamically active. But today, we are witnessing dire threats to all three. We humans, it surely goes without saying, have a history of making incredibly bad decisions about how we interact with the ecosystems that surround us, and every bad decision we make negatively influences members of our particular ecosystem as well as those of other ecosystems.

Some ecosystems are in more urgent need of attention than are others. Conservation International, The Critical Ecosystem Partnership Fund, and World Wildlife Fund have designated these suffering ecosystems as “biodiversity hotspots.”

To qualify as a biodiversity hotspot an area must meet two firm criteria.

1.      An area must contain at least 1,500 species of vascular plants¹ found nowhere else on Earth. These are known as “endemic” species.

2.      The area must have lost 70% or more of its native vegetation.

Currently, there are 36 recognized biodiversity hotspots, including such areas as the Caribbean islands, the forests of Eastern Australia, the islands of Polynesia-Micronesia, and New Zealand in its entirety.

Taken together the 36 hotspots represent only 2.4% of the planet’s land surface, and yet they support well over half of the planet’s plant species, as endemics, and 42% of all bird, reptile, amphibian and mammal species, also as endemics. The loss of vegetation in some hotspots is fast approaching 95%, and if those plant species are gone, that means they are gone. Gone forever. And where plants go, so go mammals – even human mammals.

Putting it in human terms, the 36 hotspots are home to more than 2 billion people, many of whom count among the world’s poorest. They are people who depend on healthy ecosystems for their daily survival.

Hopefully this quick snapshot of the complex mosaic that is biodiversity has been helpful. The hotspots definitely need our attention, and soon, while we also keep our eyes peeled for trouble brewing within the global biome. Small perturbations can quickly cascade into systemwide collapse, which is what we are seeing all around us today.

Biodiversity means life.

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 Notes

¹ Vascular plants are a huge group that is comprised of pretty much every kind of plant that isn’t a moss or a liverwort.

Works Consulted

“Biodiversity Hotspots.” Conservation International. https://www.conservation.org/priorities/biodiversity-hotspots. Accessed 19 June 2021.

“Millennium Ecosystem Assessment.” Ecosystems and Human Well-being: A Framework for Assessment. 2003.

Primack, Richard B. & Anna A. Sher. An Introduction to Conservation Biology. Sinauer Associates, Inc., 2016.

“What is Biodiversity?” American Museum of Natural History, https://www.amnh.org/research/center-for-biodiversity-conservation/what-is-biodiversity. Accessed 21 July 2021.