Why is biodiversity important? It is not quite as straightforward as we are being told.

Biodiversity provides a large number of goods and services that sustain our lives. Protecting biodiversity is in our self-interest. Biological resources are the pillars upon which we build civilizations. Nature’s products support such diverse industries as agriculture, cosmetics, pharmaceuticals, pulp and paper, horticulture, construction and waste treatment. […]” (Convention on Biological Diversity 2010)

Who considers this to be a conclusive statement? Well, I don’t. It is an example of the media’s simplified way of reporting on the importance of biodiversity that I suppose leaves most people uncertain about why exactly biodiversity is meaningful. Let me try and shed some light on the issue.

Nature, biodiversity, ecosystem services and biological resources are not the same thing, but often treated as such. It is quite obvious that certain ecosystem services such as the provisioning with biological resources (such as food, pharmaceuticals etc.) are essential to our lives. But why do ecosystems need to be diverse in terms of species and genes to provide their services?

This is not clear in the first place as biodiversity doesn’t necessarily enhance productivity: just consider industrialized agricultural and silvicultural production systems as opposed to natural systems. Furthermore, ecosystem services such as erosion control, oxygen production, water purification and the like depend on a system’s physical properties rather than its actual diversity (less diverse systems might get the job done as well).

So, what does biodiversity actually do?

  • It sustains ecosystem function

There is evidence of beneficial effects of biodiversity on ecosystem resilience—the capability of and ecosystem to respond to disturbances. However, uncertainty remains about how much biodiversity is needed to sustain ecosystem functions as they depend on functional groups rather than on individual species or genes (the diversity-stability debate).

  • It sustains evolutionary potential

You might call it resilience on a larger scale. It is the ability of ecosystems to adapt to a changing environment. The more diversity there is, the more likely there are varieties of genes and species able to cope with changing conditions, ensuring the ecosystem’s functionality and the provision of vital ecosystem services in the long run. Similarly, agriculture depends on a certain gene pool (including wild types) for purposive crossbreeding in view of changing environmental conditions.

The bottom line: Biodiversity sustains what ecosystems provide

Scientific evidence of correlations between diversity and ecosystem functions is not irrefutable (yet). BUT business as usual given the high human-induced pressure on biodiversity is risky. We are continually popping rivets on spaceship earth, only knowing about the importance of what we lose when it is lost. While natural resources grow again if depleted to some extent, a lost gene, species or ecosystem that has been evolving for millions of years will be lost forever.

As a precaution, we have to take care of what there is. Not only because it is, or may prove, useful. I think that ultimately, utilitarian arguments (including much of the ecosystem services concept) are not enough to justify why biodiversity conservation is important. They suggest that we can still pay later if we fail to act now. Rather than portraying the diversity of life as a mere resource to be exploited, we have to promote awareness of everyone’s responsibility to help preserve an asset that is precious beyond economical value.

Excursus: Is biodiversity all we need to care about in nature conservation?

  • Some habitats naturally contain relatively few species but are nonetheless endangered (such as for example certain peatlands, tundra and desert habitats). Focusing on “biodiversity hotspots” alone is therefore not sufficient.
  • Heavily modified habitats can potentially be more diverse than natural habitats as disturbances create niches for pioneer species and and/or exotic species (example: traditional cultural landscapes). In these cases, there is a trade-off between naturalness and biodiversity, so biodiversity may or may not be the principal conservation objective.
Field trip to a natural temperate grassland north of Canberra (22/02/2013) – a habitat under anthropogenic pressure.

Field trip to a natural temperate grassland north of Canberra (22/02/2013) – a habitat under anthropogenic pressure.

Constantin Harrer, exchange student from ETH Zürich, environmental sciences BSc

Further reading:


About Biodiversity Conservation Blog

I am an Associate Professor at The Australian National University and convene a (very awesome) course called Biodiversity Conservation. Myself and students in the course contribute to this blog.
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